EPA 815-Z-OO-ODi
Monday,

April 10, 2000
Part H



Environmental

Protection Agency

40 CFR Parts 141 and 142
National Primary Drinking Water
Regulations: Long Term 1 Enhanced
Surface Water Treatment and Filter
Backwash Rule; Proposed Rule

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 19046
Federal Register/Vol. 65, No.  69/Monday, April 10, 2000/Proposed Rules
 ENVIRONMENTAL PROTECTION
 AGENCY

 40 CFR Parts 141 and 142
 [WH-FRL-6570-5]
 RIN 2040-AD18

 National Primary Drinking Water
 Regulations: Long Term 1 Enhanced
 Surface Water Treatment and Filter
 Backwash Rule

 AGENCY: Environmental Protection
 Agency (EPA).
 ACTION: Proposed rule.

 SUMMARY: In this document, EPA is
 proposing the Long Term 1 Enhanced
 Surface Water Treatment and Filter
 Backwash Rule (LTlFBR). The purposes
 of the LTlFBR are to: Improve control
 of microbial pathogens in drinking
 water, including Cryptosporidium, for
 public water systems (PWSs) serving
 fewer than 10,000 people; prevent
 increases in microbial risk while PWSs
 serving fewer than 10,000 people
 control for disinfection byproducts, and;
 require certain PWSs to institute
 changes to the return of recycle flows
 within the treatment process to reduce
 the effects of recycle on compromising
 microbial control. Today's proposal
 addresses two statutory requirements of
 the 1996 Safe Drinking Water Act
 (SDWA) Amendments. First, it
 addresses the statutory requirement to
 establish a Long Term Final Enhanced
 Surface Water Treatment Rule
 (LTESWTR) for PWSs that serve under
 10,000 people. Second, it addresses the
 statutory requirement to promulgate a
 regulation which "governs" the recycle
 of filter backwash within the treatment
 process of public utilities.
  Today's proposed LTlFBR contains 5
 key provisions for surface water and
ground water under the direct influence
 of surface water (GWUDI) systems
 serving fewer than 10,000 people: A
treatment technique requiring a 2-log
 (99 percent) Cryptosporidium removal
requirement; strengthened combined
filter effluent turbidity performance
standards and new individual filter
turbidity provisions; disinfection
benchmark provisions to assure
continued microbial protection is
provided while facilities take the
necessary steps to comply with new
                    disinfection byproduct standards;
                    inclusion of Cryptqsporidium in the
                    definition of GWUDI and in the
                    watershed control requirements for
                    unfiltered public water systems; and
                    requirements for covers on new finished
                    water reservoirs,
                      Today's proposed LTlFBR contains
                    three key provisions for all conventional
                    and direct filtration systems which
                    recycle and use surface water or
                    GWUDI: A provision requiring recycle
                    flows to be introduced prior to the point
                    of primary coagulant addition; a
                    requirement for systems meeting criteria
                    to perform a one-time self assessment of
                    their recycle practice and consult with
                    their primacy agency to address and
                    correct high risk recycle operations; and
                    a requirement for direct filtration
                    systems to provide information to the
                    State on their current recycle practice.
                      The Agency believes implementing
                    the provisions contained in today's
                    proposal will improve public health
                    protection in two fundamental ways.
                    First, the provisions will reduce the
                    level of Cryptosporidium in filtered
                    finished drinking water supplies
                    through improvements in filtration and
                    recycle practice resulting in a reduced
                    likelihood of outbreaks of
                    cryptosporidiosis. Second, the filtration
                    provisions are expected to increase the
                    level of protection from exposure to
                    other pathogens (i.e. Giardia or other
                    waterborne bacterial or viral pathogens).
                    It is also important to note that while
                    today's proposed rule contains new
                    provisions which in some cases
                    strengthen or modify requirements of
                    the 1989 Surface Water Treatment Rule,
                    each public water system must continue
                    to comply with the current rules while
                    new microbial and disinfectants/
                    disinfection byproducts rules are being
                    developed. In conjunction with the
                    Maximum Contaminant Level Goal
                    (MCLG) established in the Interim
                    Enhanced Surface Water Treatment
                    Rule, the Agency developed a treatment
                    technique in lieu of a Maximum
                    Contaminant Level (MCL) for
                    Cryptosporidium because it is not
                    economically and technologically
                    feasible to accurately ascertain the level
                    of Cryptosporidium using current
                    analytical methods.
                    DATES: The Agency requests comments
                    on today's proposal. Comments must be
 received or post-marked by midnight
 June 9, 2000. Comments received after
 this date may not be considered in
 decision making on the proposed rule.
 ADDRESSES: Send written comments on
 today's proposed rule to the LTlFBR
 Comment Clerk: Water Docket MC 410,
 W-99-10, Environmental Protection
 Agency 401 M Street, S.W., Washington,
 DC 20460. Please submit an original and
 three copies of comments and
 enclosures (including references).
  Those who comment and want EPA to
 acknowledge receipt of their comments
 must enclose a self-addressed stamped
 envelope. No facsimiles (faxes) will be
 accepted. Comments may also be
 submitted electronically to ow-
 docket@epamail.epa.gov. For additional
 information on submitting electronic
 comments see Supplementary
 Information Section.
  Public comments on today's proposal,
 other major supporting documents, and
 a copy of the index to the public docket
 for this rulemaking are available for
 review at EPA's Office of Water Docket:
 401 M Street, SW., Rm. EB57,
 Washington, DC 20460 from 9:00 a.m. to
 4:00 p.m., Eastern Time, Monday
 through Friday, excluding legal
 holidays. For access to docket materials
 or to schedule an appointment please
 call (202) 260-3027.
 FOR FURTHER INFORMATION CONTACT:
 Technical inquiries on the rule should
 be directed to Jeffery Robichaud at 401
 M Street, SW., MC4607, Washington,
 DC 20460 or (202) 260-2568. For
 general information contact the Safe
 Drinking Water Hotline, Telephone
 (800) 426-4791. The Safe Drinking
 Water Hotline is open Monday through
 Friday, excluding federal holidays, from
 9:00 a.m. to 5:30 p.m. Eastern Time.
 SUPPLEMENTARY INFORMATION: Entities
 potentially regulated by the LTlFBR are
 public water systems (PWSs) that use
 surface water or ground water under the
 direct influence of surface water
 (GWUDI). The recycle control
provisions are applicable to all PWSs
using surface water or GWUDI,
regardless of the population served. All
 other provisions of the LTlFBR are only
applicable to PWSs serving under
 10,000 people. Regulated categories and
entities include:
Category
Industry 	
State, Local, Tribal or Fed-
eral Governments.
Examples of regulated entities

Public Water Systems that use surface water or ground water under the direct influence of surface water.

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                  Federal  Register/Vol. 65, No.  69/Monday, April  10,  2000/Proposed Rules
                                                                    19047
  This table is not intended to be
exhaustive, but rather provides a guide
for readers regarding entities likely to be
regulated by the LT1FBR. This table
lists the types of entities that EPA is
now aware could potentially be
regulated by this rule. Other types of
entities not listed in this table could
also be regulated. To determine whether
your facility is regulated by this action,
you should carefully examine the
definition of public water system in
§ 141.3 of the Code of Federal
Regulations and applicability criteria in
§§ 141.76 and 141.501 of today's
proposal. If you have questions
regarding the applicability of the
LTlFBR to a particular entity, consult
the person listed in the preceding
section entitled FOR  FURTHER
INFORMATION CONTACT.
Submitting Comments
  Send an original and three copies of
your comments and  enclosures
(including references) to W-99-10
Comment Clerk, Water Docket
(MC4101), USEPA, 401 M Street, SW.,
Washington, D.C. 20460. Comments
must be received or  post-marked by
midnight June 9, 2000. Note that the
Agency is not soliciting comment on,
nor will it respond to, comments on
previously published regulatory
language that is included in this
document to ease the reader's
understanding of the proposed
language.
  To ensure that EPA can read,
understand and therefore properly
respond to comments, the Agency
would prefer that commenters cite,
where possible, the paragraph(s) or
sections in the proposed rule or
supporting documents to which each
comment refers. Commenters should
use a separate paragraph for each issue
discussed.
Electronic Comments
  Comments may also be submitted
electronically to ow-
docket@epamail.epa.gov. Electronic
comments must be submitted as an
ASCII, WP5.1, WP6.1 or WPS file
avoiding the use of special characters
and form of encryption. Electronic
comments must be identified by the
docket number W-99-10. Comments
and data will also be accepted on disks
in WP 5.1, 6.1, 8 or ASCII file format.
Electronic comments on this document
may be filed online at many Federal
Depository Libraries.
  The record for this rulemaking has
been established under docket number
W-99-10, and includes supporting
documentation as well as printed, paper
versions of electronic comments. The
record is available for inspection from 9
a.m. to 4 p.m., Monday through Friday,
excluding legal holidays at the Water
Docket, EB 57, USEPA Headquarters,
401 M Street, SW., Washington, D.C. For
access to docket materials, please call
(202) 260-3027 to schedule an
appointment.

List of Abbreviations Used in This
Document
ASCE  American Society of Civil
    Engineers
ASDWA Association of State Drinking
    Water Administrators
ASTM  American Society for Testing
    Materials
AWWA  American Water Works
    Association
AWWARF   American Water Works
    Association Research Foundation
°C  Degrees Centigrade
CCP  Composite Correction Program
CDC  Centers for Disease Control
CFE  Combined Filter Effluent
CFR  Code of Federal Regulations
COI  Cost of Illness
CPE  Comprehensive Performance
    Evaluation
CT  The Residual Concentration of
    Disinfectant (mg/L) Multiplied by
    the Contact Time (in minutes)
CTA  Comprehensive Technical
    Assistance
CWSS  Community Water System
    Survey
DBFs  Disinfection Byproducts
DBPR Disinfectants/Disinfection
    Byproducts Rule
ESWTR  Enhanced Surface Water
    Treatment Rule
FACA  Federal Advisory Committee
    Act
GAG  Granular Activated Carbon
GAO Government Accounting Office
GWUDI  Ground Water Under the
    Direct Influence of Surface Water
HAAS  Haloacetic acids
    (Monochloroacetic, Dichloroacetic,
    Trichloroacetic, Monobromoacetic
    and Dibromoacetic Acids)
HPC  Heterotropic Plate Count
hrs  Hours
ICR  Information Collection Rule
IESWTR  Interim Enhanced Surface
    Water Treatment Rule
IFA  Immunofluorescence Assay
Log Inactivation  Logarithm of (N0/Nr)
Log  Logarithm (common, base 10)
LTESWTR  Long Term Enhanced
    Surface Water Treatment Rule
LTlFBR Long Term 1 Enhanced
    Surface Water Treatment and Filter
    Backwash Rule
MCL Maximum Contaminant Level
MCLG  Maximum Contaminant Level
    Goal
MGD  Million Gallons per Day
M-DBP   Microbial and Disinfectants/
    Disinfection Byproducts
MPA  Microscopic Particulate Analysis
NODA  Notice of Data Availability
NPDWR  National Primary Drinking
    Water Regulation
NT  The Concentration of Surviving
    Microorganisms at Time T
NTTAA  National Technology Transfer
    and Advancement Act
NTU  Nephelometric  Turbidity Unit
PE  Performance Evaluation
PWS  Public Water System
Reg. Neg.  Regulatory Negotiation
RIA Regulatory Impact Analysis
RFA  Regulatory Flexibility Act
RSD  Relative Standard Deviation
SAB  Science Advisory Board
SDWA  Safe Drinking Water Act
SWTR  Surface Water Treatment Rule
TC  Total Coliforms
TCR  Total Coliform Rule
TTHM  Total Trihalomethanes
TWG  Technical Work Group
TWS  Transient Non-Community Water
    System
UMRA  Unfunded Mandates Reform
    Act
URCIS  Unregulated Contaminant
    Information System
x log removal  Reduction to 1/10X of
    original concentration

Table of Contents
I. Introduction and Background
A. Statutory Requirements and Legal
    Authority
B. Existing Regulations and Stakeholder
    Involvement
  1. 1979 Total Trihalomethane Rule
  2. Total Coliform Rule
  3. Surface Water Treatment Rule
  4. Information Collection Rule
  5. Interim Enhanced Surface Water
    Treatment Rule
  6. Stage 1 Disinfectants and Disinfection
    Byproduct Rule
  7. Stakeholder Involvement
II. Public Health Risk
A. Introduction
B. Health Effects of Cryptosporidiosis and
    Sources and Transmission of
    Cryptosporidium
C. Waterborne Disease Outbreaks In the
    United States
D. Source Water Occurrence Studies
E. Filter Backwash and Other Process
    Streams: Occurrence and Impact Studies
F. Summary and Conclusions
III. Baseline Information-Systems Potentially
Affected By Today's Proposed Rule

IV. Discussion of Proposed LTlFBR
Requirements
A. Enhanced Filtration Requirements
  1. Two Log Cryptosporidium Removal
    Requirement
  a. Two Log Removal
  i. Overview and Purpose
  ii. Data
  iii. Proposed Requirements
  iv. Request for Comments
  2. Turbidity Requirements
  a. Combined Filter Effluent

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Federal Register/Vol. 65,  No.  69/Monday, April  10,  2000/Proposed  Rules
  i. Overview and Purpose
  ii. Data
  iii. Proposed Requirements
  iv. Request for Comments
  b. Individual Filter Turbidity
  i. Overview and Purpose
  ii. Data
  iii. Proposed Requirements
  iv. Request for Comments
B. Disinfection Benchmarking Requirements
  1. Applicability Monitoring
  a. Overview and Purpose
  b. Data
  c. Proposed Requirements
  d. Request for Comment
  2. Disinfection Profiling
  a. Overview and Purpose
  b. Data
  c. Proposed Requirements
  d. Request for Comments
  3. Disinfection Benchmarking
  a. Overview and Purpose
  b. Data
  c. Proposed Requirements
  d. Request for Comments
C. Additional Requirements
1. Inclusion of Cryptosporidium In Definition
    ofGWUDI
  a. Overview and Purpose
  b. Data
  c. Proposed Requirements
  d. Request for Comments
2. Inclusion of Cryptosporidium Watershed
    Requirements for Unfiltered Systems
  a. Overview and Purpose
  b. Data
  c. Proposed Requirements
  d. Request for Comments
3. Requirements for Covering New Reservoirs
  a. Overview and Purpose
  b. Data
  c. Proposed Requirements
  d. Request for Comments
  D. Recycle Provisions for Public Water
    Systems Employing Rapid Granular
    Filtration Using Surface Water and
    GWUDI as a Source
  1. Treatment Processes that Commonly
    Recycle and Recycle Flow Occurrence
    Data
  a. Treatment Processes that Commonly
    Recycle
  i. Conventional Treatment Plants
  ii. Direct Filtration Plants
  iii. Softening Plants
  iv. Contact Clarification Plants
  v. Package Plants
  vi. Summary of Recycle Disposal Options
  b. Recycle Flow Occurrence Data
  i. Untreated Spent Filter Backwash Water
  ii. Gravity Settled Spent Filter Backwash
    Water
  iii. Combined Gravity Thickener
    Supernatant
  iv. Gravity Thickener Supernatant from
    Sedimentation Solids
  v. Mechanical Dewatering Device Liquids
  2. National Recycle Practices
  a. Information Collection Rule
  i. Recycle Practice
  b. Recycle FAX  Survey
  i. Recycle practice
  ii. Options to recycle
  iii. Conclusions
  3. Recycle Provisions for PWSs Employing
    Rapid Granular Filtration Using Surface
                          Water or Ground Water Under the Direct
                          Influence of Surface Water Influence of
                          Surface Water ,
                        a. Return Select Recycle Streams Prior to
                          the Point of Primary Coagulant Addition
                        i. Overview and Purpose
                        ii. Data
                        iii. Proposed Requirements
                        iv. Request for Comments
                        b. Recycle Requirements for Systems
                          Practicing Direct Recycle and Meeting
                          Specific Criteria
                        i. Overview and Purpose
                        ii. Data
                        iii. Proposed Requirements
                        iv. Request for Comments
                        c. Requirements for Direct Filtration Plants
                          that Recycle Using Surface Water or
                          GWUDI
                        i. Overview and Purpose
                        ii. Data
                      iii.  Proposed Requirements
                      iv. Request for Comments
                      d. Request for Additional Comment
                      V. State Implementation and Compliance
                      Schedules
                      A. Special State Primacy Requirements
                      B. State Recordkeeping Requirements
                      C. State Reporting Requirements
                      D. Interim Primacy
                      E. Compliance Deadlines
                      VI.  Economic Analysis
                      A. Overview
                      B. Quantifiable and Non-Quantifiable Costs
                        1. Total Annual Costs
                        2. Annual Costs of Rule Provisions
                        3. Non Quantifiable Costs
                      C. Quantifiable and Non-Quantifiable Health
                          Benefits
                        1. Quantified Health Benefits
                        2. Non-Quantified Health and Non-Health
                          Related Benefits
                        a. Recycle Provisions
                        b. Issues Associated with Unquantified
                          Benefits
                      D. Incremental Costs  and Benefits
                      E. Impacts on Households
                      F. Benefits From the Reduction of Co-
                          Occurring Contaminants
                      G. Risk Increases From Other Contaminants
                      H. Other Factors: Uncertainty in Risk,
                          Benefits, and Cost Estimates
                      I. Benefit Cost Determination
                      J. Request for Comment
                      VII. Other Requirements
                      A. Regulatory Flexibility Act
                        1. Today's Proposed Rule
                        2. Use of Alternative Definition
                        3. Background and Analysis
                        a. Number of Small Entities Affected
                        b. Recordkeeping and Reporting
                        c. Interaction with Other Federal Rules
                        d. Significant Alternatives
                        i. Turbidity Provisions
                        ii. Disinfection Benchmarking
                          Applicability Monitoring Provisions
                        iii. Recycling Provisions
                        e. Other Comments
                      B. Paperwork Reduction Act
                      C. Unfunded Mandates Reform Act
                        1. Summary of UMRA requirements
                        2. Written Statement for Rules With
                          Federal Mandates of $100 Million or ,
                          More
   a. Authorizing Legislation
   b. Cost Benefit Analysis
   c. Estimates of Future Compliance Costs
    and Disproportionate Budgetary Effects
   d. Macro-economic Effects
   e. Summary of EPA's Consultation with
    State, Local, and Tribal Governments
    and Their Concerns
   f. Regulatory Alternatives Considered
   g. Selection of the Least Costly, Most-Cost
    Effective or Least Burdensome
    Alternative That Achieves the Objectives
    of the Rule
   3. Impacts on Small Governments
 D. National Technology Transfer and
    Advancement Act
 E. Executive Order 12866: Regulatory
    Planning and Review
 F. Executive Order 12898: Environmental
    Justice
 G. Executive Order 13045: Protection of
    Children from Environmental Health
    Risks and Safety Risks
 H. Consultations with the Science Advisory
    Board, National Drinking Water
    Advisory Council, and the Secretary of
    Health and Human Services
 I. Executive Order 13132: Executive Orders
    on Federalism
 J. Executive Order 13084: Consultation and
    Coordination With Indian Tribal
    Governments
 K. Likely Effect of Compliance with the
    LT1FBR on the Technical, Financial, and
    Managerial Capacity of Public Water
    Systems
 L. Plain Language
 VIII. Public Comment Procedures
 A. Deadlines for Comment
 B. Where to Send Comment
 C. Guidelines for Commenting
 IX. References

 I.  Introduction and Background

 A. Statutory Requirements and Legal
 Authority
   The Safe Drinking Water Act (SDWA
 or the Act), as amended in 1986,
 requires U.S. Environmental Protection
 Agency (EPA) to publish a maximum
 contaminant level  goal (MCLG) for each
 contaminant which, in the judgement of
 the EPA Administrator, "may have any
 adverse effect on the health of persons
 and which is known or anticipated to
 occur in public water systems' (Section
 1412(b)(3)(A)). MCLGs are to be set at a
 level  at which "no known or anticipated
 adverse effect on the health of persons
 occur and which allows an adequate
 margin of safety" (Section 1412(b)(4)).
   The Act was again amended in
 August 1996, resulting in the
renumbering and augmentation of
certain sections with additional
 statutory language. New sections were
 added establishing new drinking water
requirements. These modifications are
 outlined below.
  The Act requires EPA to publish a
National Primary Drinking Water
Regulation (NPDWR) that specifies

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                                                                   19049
either a maximum contaminant level
(MCL) or treatment technique (Sections
1401(1) and 1412(a)(3)) at the same time
it publishes an MCLG, which is a non-
enforceable health goal. EPA is
authorized to promulgate a NPDWR
"that requires the use of a treatment
technique in lieu of establishing an
MCL," if the Agency finds that "it is not
economically or technologically feasible
to ascertain the level of the
contaminant." EPA's general authority
to set MCLGs and NPDWRs applies to
contaminants that may "have an adverse
effect on the health of persons," that are
"known to occur or there is a substantial
likelihood that the contaminant will
occur in public water systems with a
frequency and  at levels of public health
concern," and  for which "in the sole
judgement of the Administrator,
regulation of such contaminant presents
a meaningful opportunity for health risk
reduction for persons served by public
water systems" (SDWA Section
  The 1996 amendments, also require
EPA, when proposing a NPDWR that
includes an MCL or treatment
technique, to publish and seek public
comment on an analysis of health risk
reduction and cost impacts. EPA is
required to take into consideration the
effects of contaminants upon sensitive
subpopulations (i.e., infants, children,
pregnant women, the elderly, and
individuals with a history of serious
illness), and other relevant factors
(Section 1412(b)(3)(Q).
  The amendments established a
number of regulatory deadlines,
including schedules for a Stage 1
Disinfection Byproduct Rule (DBPR), an
Interim Enhanced Surface Water
Treatment Rule (IESWTR), a Long Term
Final Enhanced Surface Water
Treatment Rule (LTESWTR), and a Stage
2 DBPR (Section 1412(b)(2)(Q). To
provide additional time for systems
serving fewer than 10,000 people to
comply with the IESWTR provisions
and also ensure these systems
implement Stage 1 DBPR and the
IESWTR provisions simultaneously, the
Agency split the IESWTR into two rules:
the IESWR and the LT1ESWTR. The Act
as amended  also requires EPA to
promulgate regulations to "govern" the
recycle of filter backwash within the
treatment process of public utilities
(Section 1412(b)(14)).
  Under 1412(b)(4)(E)(ii), EPA must
develop a Small System Technology List
for the LTlFBR. The filtration
technologies listed in the Small System
Compliance Technology List for the
Surface Water Treatment Rule and Total
Coliform Rule (EPA-815-R-98-001,
September 1998) are also the
technologies which would achieve
compliance with the provisions of the
LTlFBR. EPA will develop a separate
list for the LTlFBR as new technologies
become available.
  Although the Act permits small
system variances for compliance with a
requirement of a national primary
drinking water regulation which
specifies a maximum contaminant level
or treatment technique, Section
1415(e)(6)(B) of SDWA, excludes
variances for any national primary
drinking water regulation for a
microbial contaminant or an indicator
or treatment technique for a microbial
contaminant. LTlFBR requires
treatment techniques to control
Cryptosporidium (a microbial
contaminant), and as such systems
governed by the LTlFBR are ineligible
for variances.
  Finally,  as part of the 1996 SDWA
Amendments, recordkeeping
requirements were modified to apply to
every person who is subject to a
requirement of this title or who is a
grantee (Section 1445(a)(l)(A)). Such
persons are required to establish and
maintain such records, make such
reports, conduct such monitoring, and
provide such information as the
Administrator may reasonably require
by regulation.
B. Existing Regulations and Stakeholder
Involvement
1. 1979 Total Trihalomethane Rule
  In November 1979 (44 FR 68624)
(EPA, 1979) EPA set an interim MCL for
total trihalomethanes (TTHM—the sum
of chloroform, bromoform,
bromodichloromethane,
dibromochloromethane) of 0.10 mg/1 as
an annual average. Compliance is
defined on the basis of a running annual
average of quarterly averages for four
samples taken in the distribution
system. The value for each sample is the
sum of the measured concentrations of
chloroform, bromodichloromethane,
dibromochloromethane and bromoform.
  The interim TTHM standard applies
to community water systems using
surface water and/or ground water
serving at  least 10,000 people that add
a disinfectant to the drinking water
during any part of the treatment process.
At their discretion, States may extend
coverage to smaller PWSs; however,
most States have not exercised this
option. The Stage 1 DBPR (as discussed
later) contains updated TTHM
requirements.

2. Total Coliform Rule
   The Total Coliform Rule (TCR) (54 FR
27544, June 29, 1989) (EPA, 1989a)
applies to all public water systems. The
TCR sets compliance with the
Maximum Contaminant Level (MCL) for
total coliforms (TC) as follows. For
systems that collect 40 or more samples
per month, no more than 5 percent of
the samples may be TC-positive; for
those that collect fewer than 40 samples,
no more than one sample may be TC-
positive. If a system has a TC-positive
sample, it must test that sample for the
presence of fecal coliforms or E. coli.
The system must also collect a set of
repeat samples, and analyze for TC (and
fecal coliform or E. coli within 24 hours
of the first TC-positive sample).
  In addition, any fecal cohform-
positive repeat sample, B-co/j.-positive
repeat sample, or any total-coliform-
positive repeat sample following a fecal
coliform-positive or E-coli-positive
routine sample constitutes an acute
violation of the MCL for total coliforms.
If a system exceeds the MCL, it must
notify the public using mandatory
language developed by the EPA. The
required monitoring frequency for a
system depends on the number of
people served and ranges from 480
samples per month for the largest
systems to once annually for the
smallest systems. All systems must have
a written plan identifying where
samples are to be collected.
  The TCR also requires an on-site
inspection (referred to as a sanitary
survey) every 5 years for each system
that collects fewer than five  samples per
month. This requirement is extended to
every 10 years for non-community
systems using only protected and
disinfected ground water.

3. Surface Water Treatment Rule
  Under the Surface Water Treatment
Rule (SWTR)  (54 FR 27486, June 29,
1989) (EPA, 1989b), EPA set maximum
contaminant level goals of zero for
Giardia lamblia, viruses, and Legionella
and promulgated regulatory
requirements for all PWSs using surface
water sources or ground water sources
under the direct influence of surface
water. The SWTR includes treatment
technique requirements for filtered and
unfiltered systems that are intended to
protect against the adverse health effects
of exposure to Giardia lamblia, viruses,
and Legionella, as well as many other
pathogenic organisms. Briefly, those
requirements include (1) Requirements
for maintenance of a disinfectant
residual in the distribution system; (2)
removal and/or inactivation of 3 log
(99.9 percent) for Giardia and 4 log
(99.99 percent) for viruses; (3) combined
filter effluent turbidity performance
standard of 5  nephelometric turbidity
units (NTU) as a maximum and 0.5 NTU

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at the 95th percentile monthly, based on
4-hour monitoring for treatment plants
using conventional treatment or direct
filtration (with separate standards for
other filtration technologies); and (4)
watershed protection and other
requirements for unfiltered systems.
Systems seeking to avoid filtration were
required to meet avoidance criteria and
obtain avoidance determination by
December 30, 1991, otherwise filtration
must have been provided by June 29,
1993. For systems properly avoiding
filtration, later failures to meet
avoidance criteria triggered a
requirement that filtration be provided
within 18 months.

4. Information Collection Rule
  The Information Collection Rule
(ICR), which was promulgated on May
14, 1996 (61 FR 24354) (EPA, 1996)
applied to large public water systems
serving populations of 100,000 or more.
A more limited set of ICR requirements
pertain to ground water systems serving
between 50,000 and 100,000 people.
About 300 PWSs operating 500
treatment plants were involved with the
extensive ICR data collection. Under the
ICR, these PWSs monitored for water
quality factors affecting disinfection
byproduct (DBF) formation and DBFs
within the treatment plant and in the
distribution system on a monthly basis
for 18 months. In addition, PWSs were
required to provide treatment train
schematics, operating data and source
water occurrence data for bacteria,
viruses, and protozoa. Finally, a subset
of PWSs performed treatment studies,
using either granular activated carbon
(GAG) or membrane processes, to
evaluate DBF precursor removal and
control of DBFs. Monitoring for
treatment study applicability began in
September 1996. The remaining
occurrence monitoring began in July
1997 and concluded in December 1998.
  The purpose of the ICR was to collect
occurrence and treatment information to
help evaluate the need for possible
changes to the current microbial
requirements and existing microbial
treatment practices, and to help evaluate
the need for future regulation of
disinfectants and disinfection
byproducts (DBFs). The ICR will
provide EPA with additional
information on the national occurrence
in drinking water of (1) chemical
byproducts that form when disinfectants
used for microbial control react with
naturally occurring compounds already
present in source water; and (2) disease-
causing microorganisms, including
Cryptosporidium, Giardia, and viruses.
Analysis of ICR data is not expected to
be completed in the time frame
                     necessary for inclusion in the LTlFBR,
                     however if the data is available and has
                     been quality controlled and peer
                     reviewed during the necessary time
                     frame, EPA will consider the datat as it
                     refines its analysis for the final rule.
                       The ICR also required PWSs to
                     provide engineering data on how they
                     currently control for such contaminants.
                     The ICR monthly sampling data will
                     also provide information on the quality
                     of the recycle waters via monthly
                     monitoring (for 18 months) of pH,
                     alkalinity, turbidity, temperature,
                     calcium and total hardness, TOG, UV254,
                     bromide, ammonia, and disinfectant
                     residual (if disinfectant is used). This
                     data will provide some indication of the
                     treatability of the water, the extent to
                     which contaminant concentration
                     effects may occur, and the potential for
                     contribution to DBF formation.
                     However, sampling to determine the
                     occurrence of pathogens in recycle
                     waters was not performed.

                     5. Interim Enhanced Surface Water
                     Treatment Rule

                       Public water systems serving 10,000
                     or more people that use surface water or
                     ground water under the direct influence
                     of surface water (GWUDI) are required
                     to comply with the IESWTR (63 FR
                     69477, December 16, 1998) (EPA, 1998a)
                     by December of 2001. The purposes of
                     the IESWTR are to improve control of
                     microbial pathogens, specifically the
                     protozoan Cryptosporidium, and
                     address risk trade-offs between
                     pathogens and disinfection byproducts.
                     Key provisions established by the rule
                     include: a Maximum Contaminant Level
                     Goal (MCLG) of zero for
                     Cryptosporidium; 2-log (99 percent)
                     Cryptosporidium removal requirements
                     for systems that filter; strengthened
                     combined filter effluent turbidity
                     performance standards of 1.0 NTU as a
                     maximum and 0.3 NTU at the 95th
                     percentile monthly, based on 4-hour
                     monitoring for treatment plants using
                     conventional treatment or direct
                     filtration; requirements for individual
                     filter turbidity monitoring; disinfection
                     benchmark provisions to assess the level
                     of microbial protection provided as
                     facilities take the necessary steps to
                     comply with new disinfection
                     byproduct standards; inclusion of
                    .Cryptosporidium in the definition of
                     GWUDI and in the watershed control
                     requirements for unfiltered public water
                     systems; requirements for covers on new
                     finished water reservoirs; and sanitary
                     surveys for all surface water systems
                     regardless of size.
 6. Stage 1 Disinfectants and Disinfection
 Byproduct Rule
   The Stage 1 DBPR applies to all PWSs
 that are community water systems
 (CWSs) or nontransient noncommunity
 water systems (NTNCWs) that treat their
 water with a chemical disinfectant for
 either primary or residual treatment. In
 addition, certain requirements for
 chlorine dioxide apply to transient
 noncommunity water systems
 (TNCWSs).  The  Stage 1 DBPR (EPA,
 1998c)  was  published at the same time
 as the IESWTR (63 FR 69477, December
 16, 1998) (EPA,  1998a). Surface water
 and GWUDI systems serving at least
 10,000  persons are required to comply
 with the Stage 1 Disinfectants and
 Disinfection Byproducts Rule by
 December 2001. Ground water systems
 and surface water and GWUDI systems
 serving fewer than 10,000 must comply
 with the Stage 1 Disinfectants and
 Disinfection Byproducts Rule by
 December 2003.
   The Stage 1 DBPR finalizes maximum
 residual disinfectant level goals
 (MRDLGs) for chlorine, chloramines,
 and chlorine dioxide; MCLGs for four
 trihalomethanes (chloroform,
 bromodichloromethane,
 dibromochloromethane, and
 bromoform), two haloacetic acids
 (dichloroacetic acid and trichloroacetic
 acid), bromate, and chlorite; and
 NPDWRs for three disinfectants
 (chlorine, chloramines, and chlorine
 dioxide), two groups of organic
 disinfection byproducts TTHMs and
 HAAS and two inorganic disinfection
 byproducts, chlorite  and bromate. The
 NPDWRs consist of maximum residual
 disinfectant levels (MRDLs) or
 maximum contaminant levels (MCLs) or
 treatment techniques for these
 disinfectants and their byproducts. The
 NPDWRs also include monitoring,
 reporting, and public notification
 requirements for these compounds. The
 Stage 1 DBPR includes the best available
 technologies (BATs) upon which the
 MRDLs and MCLs are based. EPA
 believes the implementation of the Stage
 1 DBPR will reduce the levels of
 disinfectants and disinfection
 byproducts  in drinking water supplies.
 The Agency believes the rule will
 provide public health protection for an
 additional 20 million households that
 were not previously covered by drinking
 water rules for disinfection byproducts.
' 7. Stakeholder Involvement
  EPA conducted two stakeholder
 meetings to  solicit feedback and
 information from the regulated
 community and  other concerned
 stakeholders on issues relating to

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                  Federal Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed Rules
                                                                     19051
today's proposed rule. The first meeting
was held July 22 and 23,1998 in
Lakewood, Colorado. EPA presented
potential regulatory components for the
LTlFBR. Breakout sessions with
stakeholders were held to generate
feedback on the regulatory provisions
being considered and to solicit feedback
on next steps for rule development and
stakeholder involvement. Additionally,
information was presented summarizing
ongoing research and data gathering
activities regarding the recycle of filter
backwash. The presentations generated
useful discussion and provided
substantial feedback to EPA regarding
technical issues, stakeholder concerns,
and possible regulatory options (EPA
1999k), The second stakeholder meeting
was held in Dallas, Texas on March 3
and 4,1999. EPA presented new
analyses, summaries of current research,
and revised regulatory options and data
collected since the July stakeholder
meeting. Regional perspectives on
turbidity and disinfection benchmarking
components were also discussed with
presentations from EPA Region VI and
the Texas Natural Resources
Conservation Commission. Four break-
out sessions were extremely useful and
generated a wide range of information,
issues, and technical input from a
diverse group of stakeholders (EPA
1999J).
  The Agency utilized the feedback
received during these two stakeholder
meetings in developing today's
proposed rule. EPA also mailed a draft
version of the preamble for today's
proposed rule to the attendees of these
meetings. Several of the options which
are presented today represent
modifications suggested by
stakeholders.
II. Public Health Risk
  The purpose of this section, is to
discuss the health risk associated with
pathogens,  particularly
Cryptosporidium, in surface waters and
GVVUDI. More detailed information
about such pathogens and other
contaminants of concern may be found
in an EPA criteria document for Giardia
(EPA 1998d), three EPA criteria
documents for viruses (EPA, 1985;
1999a; 1999b), the Cryptosporidium and
Giardia Occurrence Assessment for the
Interim Enhanced Surface Water
Treatment Rule (EPA, 1998b) and the
LTlFBR Occurrence and Assessment.
Document (EPA 1999c). EPA requests
comment on today's proposed rule, the
information supporting the proposal,
and the potential impact of proposed
regulatory provisions on public health
risk.
A. Introduction

  In 1990, EPA's Science Advisory
Board (SAB), an independent panel of
experts established by Congress, cited
drinking water contamination as one of
the most important environmental risks
and indicated that disease-causing
microbial contaminants (i.e., bacteria,
protozoa and viruses) are probably the
greatest remaining health risk
management challenge for drinking
water suppliers (EPA/SAB, 1990).
Information on the number of
waterborne disease outbreaks from the
U.S. Centers for Disease Control and
Prevention (CDC) underscores this
concern. CDC indicates that, between
1980 and 1996, 401 waterborne disease
outbreaks were reported, with over
750,000 associated cases of disease.
During this period, a number of agents
were implicated as the cause, including
protozoa, viruses and bacteria.
  Waterborne disease caused by
Cryptosporidium is of particular
concern, as it is difficult to inactivate
Cryptosporidium oocysts with standard
disinfection practices (unlike pathogens
such as viruses and bacteria), and there
is currently no therapeutic treatment for
cryptosporidiosis (unlike giardiasis).
Because Cryptosporidium is not
generally inactivated in systems using
standard disinfection practices, the
control of Cryptosporidium is
dependent on physical removal
processes (e.g., filtration).
  The filter effluent turbidity limits
specified under the SWTR were created
to remove large parasite cysts such as
Giardia and did not specifically control
for smaller  Cryptosporidium oocysts. In
addition, filter backwash water
recycling practices such as adding
recycled water to the treatment train
after primary coagulant addition may
overwhelm the plant and harm efforts to
control Giardia lamblia,
Cryptosporidium, and emerging
pathogens. Despite filtration and
disinfection, Cryptosporidium oocysts
have been found in filtered drinking
water (LeChevallier, et al., 1991a; EPA,
1999c), and many of the individuals
affected by waterborne disease
outbreaks caused by Cryptosporidium
were served by filtered surface water
supplies (Solo-Gabriele and Neumeister,
1996). Surface water systems that filter
and disinfect may still be vulnerable to
Cryptosporidium, depending on the
source water quality and treatment
effectiveness. EPA believes that today's
proposal, however, will ensure that
drinking water treatment is operating
efficiently to control Cryptosporidium
(see Sections IV.A and IV.D) and other
microbiological contaminants of
concern (e.g., Giardia}.
  In order to assess the public health
risk associated with consumption of
surface water or GWUDI from PWSs,
EPA has evaluated information and
conducted analysis in four important
areas discussed in the following
paragraphs. These areas are: (l) The
health effects of cryptosporidiosis; (2)
cryptosporidiosis waterborne disease
outbreak data; (3) Cryptosporidium
occurrence data from raw surface water,
raw GWUDI, finished water, and recycle
stream studies; and (4) an assessment of
the current baseline surface water
treatment required by  existing
regulations.
B. Health Effects of Cryptosporidiosis
and Sources and Transmission of
Cryptosporidium
  Waterborne diseases are usually acute
(i.e., sudden onset and typically lasting
a short time in healthy people), and
most waterborne pathogens cause
gastrointestinal illness, with diarrhea,
abdominal discomfort, nausea,
vomiting, and/or other symptoms. Some
waterborne pathogens cause or are
associated with more serious disorders
such as hepatitis, gastric cancer, peptic
ulcers, myocarditis, swollen lymph
glands, meningitis, encephalitis, and
many other diseases. Cryptosporidiosis
is a protozoal infection that usually
causes 7-14 days  of diarrhea with
possibly a low-grade fever, nausea, and
abdominal cramps in healthy
individuals (Juranek, 1995). Unlike
giardiasis for which effective antibiotic
therapy is available, an antibiotic
treatment for cryptosporidiosis does not
exist (Framm and Soave, 1997).
  There are several species of
Cryptosporidium which have been
identified, including C. baileyi and C.
meleagridis (bird host); C. muris (mouse
host); C. nasorum (fish host), C. parvum
(mammalian host), and C. serpentis
(snake host). Cryptosporidium parvum
was first recognized as a human
pathogen in 1976 (Juranek, 1995).
Recently, both the human and cattle
types of C. parvum have been found in
healthy individuals, and these types, C.
felis, and a dog type have been found in
immunocompromised individuals
(Pieniazek et al., 1999). Transmission of
cryptosporidiosis often occurs through
the ingestion of infective
Cryptosporidium oocysts from feces-
contaminated food or water, but may
also result from direct or indirect
contact with infected persons or
mammals (Casemore, 1990; Cordell and
Addiss, 1994). Dupont, et. al., 1995,
found through a human feeding study
that a low dose of C. parvum is

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19052
Federal  Register/Vol. 65, No.  69/Monday, April  10,  2000/Proposed Rules
sufficient to cause infection in healthy
adults (Dupont et. al., 1995). Animal
agriculture as a nonpoint source of C.
parvum has been implicated as the
source of contamination for the 1993
outbreak in Milwaukee, Wisconsin, the
largest outbreak of waterborne disease
in the history of the United States
(Walker et al., 1998). Other sources of C.
parvum include discharges from
municipal wastewater treatment
facilities and  drainage from
slaughterhouses. In addition, rainfall
appears to increase the concentration of
Cryptosporidium in surface water,
documented in a study by Atherholt, et
al. (1998).
  There is evidence that an immune
response to Cryptosporidium exists, but
the degree and duration of this
immunity is not well characterized
(Payer and Ungar, 1986). Recent work
conducted by Chappell, et al. (1999)
indicates that individuals with evidence
of prior exposure to Cryptosporidium
parvum have  demonstrated immunity to
low doses of oocysts (approximately 500
oocysts). The  investigators found the 50
percent infectious dose for previously
exposed individuals (possessing a pre-
existing blood serum antibody) to be
1,880 oocysts compared to 132 oocysts
for individuals without prior exposure,
and individuals with prior exposure
who became infected shed fewer
oocysts. Because of this type of immune
response, symptomatic infection in
communities  exposed to chronic low
levels of oocysts will primarily be
observed in newcomers (e.g., visitors,   ,
young children) (Frost et al., 1997;
Okhuysen et al., 1998).
  Sensitive populations are more likely
to become infected and ill, and
gastrointestinal illness among this
population may be chronic. These
sensitive populations include children,
especially the yery young; the elderly;
pregnant women; and the
immunocompromised (Gerba et al.,
1996; Payer and Ungar, 1986; EPA
1998e). This sensitive segment
represents almost 20 percent of the
population in the U.S. (Gerba et al.,
                     1996). EPA is particularly concerned
                     about the exposure of severely
                     immunocompromised persons to
                     Cryptosporidium in drinking water,
                     because the severity and duration of
                     illness is often greater in
                     immunocompromised persons than in
                     healthy individuals, and it may be fatal
                     among this population. For instance, a
                     follow-up study of the 1993 Milwaukee,
                     Wisconsin, waterborne disease outbreak
                     reported that at least 50
                     CryptosporiA'um-associated deaths
                     occurred among the severely
                     immunocompromised (Hoxie et al.,
                     1997).
                       Cases of illness from
                     cryptosporidiosis were rarely reported
                     until 1982, when the disease became
                     prevalent due to the AIDS epidemic
                     (Current, 1983). As laboratory diagnostic
                     techniques improved during subsequent
                     years, outbreaks among
                     immunocompetent persons were
                     recognized as well. Over the last several
                     years there have been a number  of
                     documented waterborne
                     cryptosporidiosis outbreaks in the U.S.,
                     United Kingdom, Canada and other
                     countries (Rose, 1997, Craun et al.,
                     1998).

                     C. Waterborne Disease Outbreaks in the
                     United States

                       The occurrence of outbreaks of
                     waterborne gastrointestinal infections,
                     including cryptosporidiosis, may be
                     much greater than suggested by reported
                     surveillance data (Craun and Calderon
                     1996). The CDC-EPA, and the Council
                     of State and Territorial Epidemiologists
                     have maintained a collaborative
                     surveillance program for collection and
                     periodic reporting of data on waterborne
                     disease outbreaks since 1971. The CDC
                     database and biennial CDC-EPA
                     surveillance summaries include data
                     reported voluntarily by the States on the
                     incidence and prevalence of waterborne
                     illnesses. However, the following
                     information demonstrates why the
                     reported surveillance data may under-
                     report actual outbreaks.
  The U.S. National Research Council
strongly suggests that the number of
identified and reported outbreaks in the
CDC database (both for surface and
ground waters) represents a small
percentage of actual waterborne disease
outbreaks National Research Council,
1997; Bennett et al., 1987). In practice,
most waterborne outbreaks in
community water systems are not
recognized until a sizable proportion of
the population is ill (Perz et al.)
  Healthy adults with cryptosporidiosis
may not suffer severe symptoms from
the disease; therefore, infected
individuals may not seek medical
assistance, and their cases are
subsequently not reported. Even if
infected individuals consult a
physician, Cryptosporidium may not be
identified by routine diagnostic tests for
gastroenteritis and, therefore, tends to
be under-reported in the general
population (Juranek 1995). Such
obstacles to outbreak reporting indicate
that the incidence of disease and
outbreaks of cryptosporidiosis may be
much higher than officially reported by
the CDC.
  The CDC database is based upon
responses to a voluntary and
confidential survey that is completed by
State and local public health officials.
CDC defines a waterborne disease
outbreak as occurring when at least two
persons experience a similar illness
after ingesting water (Kramer et al.,
1996). Cryptosporidiosis water system
outbreak data from the CDC database
appear in Table II.l and Table II.2.
  Table II.l illustrates the reported
number of waterborne disease outbreaks
in U.S. community, noncommunity, and
individual drinking water systems
between 1971 and 1996. According to
the CDC-EPA database, a total of 652
outbreaks and 572,829 cases of illnesses
were reported between 1971 and 1996
(see Table II-l). The total number of
outbreaks reported includes outbreaks
resulting from protozoan contamination,
virus contamination, bacterial
contamination, chemical contamination,
and unknown factors.
  TABLE 11.1.—COMPARISON OF OUTBREAKS AND OUTBREAK-RELATED ILLNESSES FROM GROUND WATER AND SURFACE
                                       WATER FOR THE PERIOD 1971-19961
Water source
Ground
Surface
Other

Total out-
breaks 2
371 (57%)
223 (34%)
58 (9%)

Cases of2
illnesses
90 815
(16%).
471 375
(82%).
10639
(2%).
Outbreaks in
CWSs
113
148
30

Outbreaks in
NCWSs
258
43
19


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                  Federal Register/Vol. 65,  No. 69/Monday,  April 10, 2000/Proposed Rules
                                                                     19053
TABLE II. 1. — COMPARISON
OF OUTBREAKS AND OUTBREAK-RELATED ILLNESSES FROM GROUND WATER AND SURFACE
WATER FOR THE PERIOD 1971-1996 1 — Continued
Water source
All Systems3 	



Total out-
breaks2
652
(100%).
Cases of2
illnesses
572,829
(100%).
Outbreaks in
CWSs
291
Outbreaks in
NCWSs
320
  'Craun and Calderon, 1994, CDC, 1998.
  2 Includes outbreaks in CWSs + NCWSs + Private wells.
  Epidemiological investigations of
outbreaks in populations served by
filtered systems have shown that
treatment deficiencies have resulted in
the plants' failure to remove
contamination from the water.
Sometimes operational deficiencies
have been discovered only during post-
outbreak investigations. Rose (1997)
identified the following types of
environmental and operating conditions
commonly present in filtered surface
water systems at the time
cryptosporidiosis outbreaks have
occurred:
  • Improperly-installed, -operated,
-maintained, or -interpreted monitoring
  • Equipment (e.g., turbidimeters);
  • Inoperable flocculates, chemical
injectors, or filters;
  • Inadequate personnel response to
failures of primary monitoring
equipment;
  • Filter backwash recycle;
  • High concentrations of oocysts in
source water with no mitigative barrier;
  • Flushing of oocysts (by heavy rain
or snow melt) from land surfaces
upstream of the plant intakes; and
  • Altered or suboptimal filtration
during periods of high turbidity, with
turbidity spikes detected in finished
water.
  From 1984  to 1994, there have been
19 reported outbreaks of
cryptosporidiosis in the U.S. (Craun et
al., 1998). As mentioned previously, C.
parvum was not identified as a human
pathogen until 1976. Furthermore,
cryptosporidiosis outbreaks were not
reported in the U.S. prior to 1984. Ten
of these cryptosporidiosis outbreaks
have been documented in CWSs,
NCWSs, and a private water system
(Moore et al., 1993; Kramer et al., 1996;
Levy et al.,  1998; ; Craun et al., 1998).
The remaining nine outbreaks were
associated with recreational activities
(Craun et al., 1998). The
cryptosporidiosis outbreaks in U.S.
drinking water systems are presented in
Table II.2.
                  TABLE 11.2.—CRYPTOSPORIDIOSIS OUTBREAKS IN U.S. DRINKING WATER SYSTEMS
Year
1984 	
1987 	 , 	
1991
1992 	
1992 	
1993 	
1993 	
1993 . . .
1994 	
1994 	

Location and CWS,
NCWS, or private
Braun Station TX
CWS.
Carrollton, GA, CWS
Berks County PA
NCWS.
Medford (Jackson
County), OR. CWS.
Talent OR CWS . .
Milwaukee Wl, CWS
Yakima, WA private
Cook County MN
NCWS.
Clark County, NV,
CWS.
Walla Walla WA
CWS.
Cases of
illness
(estimated)
117(2000) 	
(13,000) 	
(551)
(3,000; combined
total for Jackson
County and Talent,
below).
see Medford OR ..
(403,000) 	
7 	
27
1 03; many confirmed
for
cryptosporidiosis
were HIV positive.
134 	

Source water
Well ... 	
River 	
Well
Spring/River 	
Spring/River . .
Lake 	
Well 	
Lake
River/Lake 	
Well

Treatment
Chlorination 	
Conventional filtra-
tion/chlorination; in-
adequate
backwashing of
some filters.
Chlorination
Chlorination/package
filtration plant.
Chlorination/package
filtration plant.
Conventional filtration
N/A 	
Filtered chlorinated .
Prechlorination, filtra-
tion and post-filtra-
tion Chlorination.
None reported 	

Suspected cause
Sewage-contami-
nated well.
Treatment defi-
ciencies.
Ground water under
the influence of
surface water.
Source not identified.
Treatment defi-
ciencies.
High source water
contamination and
treatment defi-
ciencies.
Ground water under
the influence of
surface water.
Possible sewage
backflow from toi-
let/septic tank.
Source not identified.
Sewage contamina-
tion.
  Craun, etal., 1998.

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19054
Federal Register/Vol.  65,  No. 69/Monday, April 10,  2000/Proposed Rules
  Six of the ten cryptosporidiosis
outbreaks reported in Table II.2
originated from surface water or
possibly GWUDI supplied by public
drinking water systems serving fewer
than 10,000 persons. The first outbreak
(117 known cases, 2,000 estimated cases
of illness), in Braun Station, Texas in
1984, was caused by sewage leaking into
a ground water well suspected to be
under the influence of surface water. A
second outbreak in Pennsylvania in
1991 (551 estimated cases of illness),
occurred at a well also under the
influence of surface water. The third
and fourth (multi-episodic)  outbreaks
took place in Jackson County, Oregon in
1992 (3,000 estimated cases of illness)
and were linked to treatment
deficiencies in the Talent, OR surface
water system. A fifth outbreak (27 cases
of illness) in Minnesota, in 1993,
occurred at a resort supplied by lake
water. Finally, a sixth outbreak (134
cases of illness) in Washington in 1994,
occurred due to sewage-contaminated
wells at a CWS.
  Three of the ten outbreaks (Carollton,
GA (1987); Talent, OR (1992);
Milwaukee, WI (1993)) were caused by
water supplied by water treatment
plants where the recycle of filter
backwash was implicated as a possible
cause of the outbreak. In total, the nine
outbreaks which have taken place in
PWSs have caused an estimated 419,939
cases of illness. These outbreaks
illustrate that when treatment in place
is not operating optimally or when
source water  is highly contaminated,
Cryptosporidium may enter the finished
drinking water and infect drinking
water consumers, ultimately resulting in
waterborne disease outbreaks.

D. Source Wafer Occurrence Studies
  Cryptosporidium is common in the
environment (Rose, 1988; LeChevallier
                     et al., 1991b). Runoff from unprotected
                     watersheds allows the transport of these
                     microorganisms from sources of oocysts
                     (e.g., untreated wastewater, agricultural
                     runoff) to water bodies used as intake
                     sites for drinking water treatment
                     plants. If treatment operates
                     inefficiently, oocysts may enter the
                     finished water at levels of public health
                     concern. A particular public health
                     challenge is that simply increasing
                     existing disinfection levels above those
                     most commonly practiced for standard
                     disinfectants (i.e., chlorine or
                     chloramines) in the U.S. today does not
                     appear to be an effective strategy for
                     controlling Cryptosporidium.
                       Cryptosporidium oocysts have been
                     detected in wastewater, pristine surface
                     water, surface water receiving
                     agricultural runoff or contaminated  by
                     sewage, ground water under the direct
                     influence of surface water (GWUDI),
                     water for recreational use, and drinking
                     water (Rose 1997, Soave 1995). Over 25
                     environmental surveys have reported
                     Cryptosporidium source water
                     occurrence data from surface water or
                     GWUDI (presented in Tables II.3 and
                     II.4), which typically involved the
                     collection of a few water samples from
                     a number of sampling locations having
                     different characteristics (e.g., polluted
                     vs. pristine; lakes or reservoirs vs.
                     rivers). Results are presented as oocysts
                     per 100 liters, unless otherwise marked.
                       Each of the studies cited in Tables II. 3
                     and II.4 presents  Cryptosporidium
                     source water occurrence information,
                     including (where possible): (1) The
                     number of samples collected; (2) the
                     number of samples positive; and (3)
                     both the means and ranges for the
                     concentrations of Cryptosporidium
                     detected (where available). However,
                     the immunofluorescence assay (IFA)
                     method and other Cryptosporidium
detection methods are inaccurate and
lack adequate precision. Current
methods do not indicate the species of
Cryptosporidium identified or whether
the oocysts detected are viable or
infectious (Frey et al., 1997). The
methods for detecting Cryptosporidium
were modeled from Giardia methods,
therefore recovery of Cryptosporidium is
deficient primarily because
Cryptosporidium oocysts are more
difficult to capture due to their size
(Cryptosporidium oocysts are 4—6|i6=Sm;
Giardia cysts are 8—12|i9Sm). In
addition, it is a challenge to recover
Cryptosporidium oocysts from the filters
when they are concentrated, due to the
adhesive character of the organisms.
Other potential limitations to the
protozoan detection methods include:
(1) Filters used to concentrate the water
samples are easily clogged by debris
from the water sample; (2) interference
occurs between debris or particulates
that fluoresce due to cross reactivity of
antibodies, which results in false
positive identifications; (3) it is difficult
to view the structure of oocysts on the
membrane filter or slide, resulting in
false negative determinations; and (4)
most methods  require an advanced level
of skill to be performed accurately.
  Despite these limitations, the
occurrence information generated from
these studies demonstrates that
Cryptosporidium occurs in source
waters. The source waters for which
EPA has compiled information include
rivers, reservoirs, lakes, streams, raw
water intakes,  springs, wells under the
influence of surface water and
infiltration galleries. The most
comprehensive study in scope and
national representation (LeChevallier
and Norton, 1995) will be described in
further detail following Tables II.3 and
II.4.
     TABLE 11.3.—SUMMARY OF SURFACE WATER SURVEY AND MONITORING DATA FOR CRYPTOSPORIDIUM OOCYSTS
Sample source
Rivers .
River
Reservoirs/rivers (polluted) 	
Reservoir (pristine) 	
Impacted river 	
Lake
Stream 	
Raw water
River (pristine)
River (polluted) 	
Lake/reservoir (pristine) 	
Lake/reservoir (polluted) 	
Number of
samples (n)
25
6
6
6
11
20
19
85
59
38
34
24
Samples
positive
for
Cryptosporidium
(percent)"
100
100
100
83
100
71
74
87
32
74
53
58
Range of oocyst
cone.
(oocysts/100L)
200-1 1 200
200-580 000
19-300 	
1-13
200-11 200b
0-2200
0-24 000
7-48 400
NR
<0 1_4400b
NR 	
<0.1-380» 	
Mean
(oocysts/100L)
2510
192000(a)
99(a) 	
2(a)
2 500(q)
58(q)
109(g)
270(g) detect-
able.
29(q)
66(q)
93(q)
103(q) 	
Reference
Ongerth and Stibbs 1 987
Madore et al 1987
Rose 1988.
Rose 1988
Rose et al 1 988ab
Rose et al 1988bb
Rose et al 1988bb
LeChevallier et al 1991c
Rose et al 1991
Rose et al 1 991
Rose et al 1991
Rose et al. 1991.

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                Federal Register/Vol.  65,  No. 69/Monday, April  10, 2000/Proposed  Rules
19055
  TABLE 11.3.—SUMMARY OF SURFACE WATER SURVEY AND MONITORING DATA FOR CRYPTOSPORIDIUM OOCYSTS—
                                                 Continued
Sample source
River (all samples) . 	

(subset of all).
of all).
eslcd area (subset of all).
tural activities (subset of all).




bkfily).
bldity).
Lakes

Finished water
River/take 	 	 	 	

River 1
River 2
Dairy farm stream 	
Reservoir Inlets


Source water . 	


River 1



Raw water intakes

Raw Water
DE River Winter
DE River, Spring 	

DE River. Fall 	
Number of
samples (n)
36
g
6
6
6
56
33
37
10
10
10
179
210
262
262
147
15
15
13
60
60
72
NR
20
21
24
22
24
NR
148
NR
100 plants
18
18
18
18
Samples
positive
for
Cryptosporidium
(percent)"
97
81
100
100
100
45
48
51
100
70
70
6
6
13
52
20
73
80
77
5
12
40
24
35
19
63
82
63
37_52d
25
NR
77
NR
NR
NR
NR
Range of oocyst
cone.
(oocysts/100L)
15-45 (pristine)
1000-6,350
(agricultural).
15-42
46-697
54-360
330-6 350
NR 	
NR 	
NR 	
82-7 190
42-510
77-870
0-2,240 	
0-2,000 	
0.29-57 	
6.5-6,510 	
30-980 	
0-2,230 	
0-1,470 	
0-1,110 	
0.7-24 	
1.2-107 	
20-280 	
1-5,390" 	
0-41,700 	
0-650 	
0-1,470 	
0-2,300 	
0-2 200 	
15-43 (maxi-
ma)'1.
0.04-18 	
40-400 	
0.5-117 	
NR 	
NR 	
NR 	
NR 	
Mean
(oocysts/100L)
20 (pristine)
1 ,830 (agricul-
tural).
24(q)
162(q) 	
107(q)
1 072(q) . .
NR 	
NR 	
NR 	
480 	
250 	
250 	
3.3 (median) 	
7 (median) 	
33 (detectable)
240 (detectable)
200 	
1 88 (a) all sam-
ples 43 (g)
detected.
147 (a) all sam-
ples 61 (g)
detected.
126 (a) all sam-
ples 55 (g)
detected.
1.9(g) 1.6 (me-
dian).
6.1 (g) 60 (me-
dian).
24(g) 	
740(a)=71(g)= ...
NR 	
NR 	
58(g) 	
42(g) 	
31(g) 	
0 8-1 4J
0.3 	 	
NR 	
3(g) 	
70 per 500L(g) ..
100 per500L(g)
30 per 500L(g) ..
20 per 500L(g) ..
Reference
Hansen and Ongerth 1991.
Hansen and Ongerth 1991.
Hansen and Ongerth 1991.
Hansen and Ongerth 1991.
Hansen and Ongerth 1991.
Consonery et al. 1 992.
Consonery et al. 1992.
Consonery et al. 1992.
LeChevallier and Norton 1 992.
LeChevallier and Norton 1 992.
LeChevallier and Norton 1992.
Archer et al. 1995.
Archer et al. 1995.
LeChevallier and Norton 1995.
LeChevallier and Norton 1995.
LeChevallier et al. 1995.
States etal. 1995.
States etal. 1995.
States et al. 1 995.
LeChevallier et al. 1997b.
LeChevallier et al. 1997b.
LeChevallier et al. 1997a.
Swertfeger et al. 1997.
Stewart etal. 1997.
Stewart etal. 1997.
States etal. 1997.
States etal. 1997.
States et al. 1997.
Okun et al. 1997.
Consonery et al. 1997.
Swiger et al. 1999.
McTigue, etal. 1998.
Atherholt, etal. 1998.
Atherholt, et al. 1998.
Atherholt, etal. 1998.
Atherholt, etal. 1998.
"Rounded to nearest percent.
>>As cited in Lisle and Rose 1995.
« Based on presumptive oocyst count
11 Combined monitoring results for multiple sites in large urban water supply.
«As cited in States et al. 1997.
(a) = arithmetic average.
(g) = geometric average.
NR = not reported, NA = not applicable.

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19056
Federal  Register/Vol. 65, No.  69/Monday, April  10,  2000/Proposed Rules
            TABLE H.4.—SUMMARY OF U.S. GWUDI MONITORING DATA FOR CRYPTOSPORIDIUM OOCYSTS
Sample source
Well

Vertical wells (subcategory of above
ground water sources).
Springs (subcategory of above
ground water sources).
Infiltration galleries (subcategory of
above ground water sources).
Horizontal wells (subcategory of
above ground water sources).
Ground water 	

Springs
Wells
Vertical well Lemont Well #4 (Center
Co., PA, Aug. 1992).
Number of
samples (n)
17 (6 wells) ..
199 sitesb
149 sitesb 	
35 sitesb
4 sitesb 	
11 sitesb 	
17 	
18 	
7 (4 springs)
5 sites
6

Samples posi-
tive for
Cryptosporidium
oocysts (per-
cent)
(1 sample) 	
11b
5b 	
20b
50b 	
45b 	
41.2 	
5.6 	
57b 	
100 	
667

Range of
positive val-
ues (oocysts/
100L)
.085L
0 002-0 45d
NR
NR
NR
NR
NR
.13
0.25-10
0.26-3
NR

Mean
(oocysts/
100L)"
NA
NR
NR
NR
NR
NR
NR
.13
4
0.9
NR

Reference
Archer et al. 1995.
Hancock et al. 1998i
Hancock et al. 1998.
Hancock et al. 1998.
Hancock et al. 1998.
Hancock et al. 1998.
Rosen et al., 1996.
Rose et al. 1991.
Rose et al. 1991.
SAIC, 1997C
Lee, 1993.

  a Geometric mean reported unless otherwise indicated.
  bData are presented as the percentage of positive sites.
  cData included are confirmed positive samples not reported in Hancock, 1998.
  NA = not applicable.
  NR = not reported.
  The LeChevallier and Norton (1995)
study collected the most samples and
repeat samples from the largest number
of surface water plants nationally.
LeChevallier and Norton conducted the
study to determine the level of
Cryptosporidium in surface water
supplies and plant effluent water. In
total, surface water sources for 72
treatment plants in 15 States and 2
Canadian provinces were sampled.
Sixty-seven surface water locations were
examined. The generated data set
covered a two-year monitoring period
(March, 1991 to January, 1993) which
was combined with a previous set of
data (October, 1988 to June, 1990)
collected from most of the same set of
systems to create a database containing
five samples (IFA) per site or more for
94 percent of the 67 systems sampled.
Cryptosporidium oocysts were detected
in 135 (51.5 percent) of the 262 raw
water samples collected between March
1991 and January 1993, while 87
percent of the 85 samples were positive
during the survey period from October,
1988 to June, 1990. The geometric mean
of detectable Cryptosporidium -was 240
oocysts/lOOL, with a range from 6.5 to
6510 oocysts/lOOL. When the 1991-
1993 results (n=262) were combined
with the previous results (n=85),
Cryptosporidium was detected in 60.2
percent of the samples. The authors
hypothesize the origin of the decrease  in
detections in the second round of
sampling to be most probably linked to
fluctuating or declining source water
concentrations of Cryptosporidium
                     oocysts from the first reporting period to
                     the second.
                      LeChevallier and Norton (1995) also
                     detected Cryptosporidium oocysts in 35
                     of 262 plant effluent samples (13.4
                     percent) analyzed between 1991 and
                     1993. When detected, the oocyst levels
                     averaged 3.3 oocysts/100 L (range = 0.29
                     to 57 oocysts/100 L). A summary of
                     occurrence data for all samples in
                     filtered effluents for the years 1988 to
                     1993 showed that 32 of the water
                     treatment plants (45 percent) were
                     consistently negative for
                     Cryptosporidium; 24 plants (34 percent)
                     were positive once; and 15 plants (21
                     percent) were positive for
                     Cryptosporidium two or more times
                     between 1988 to 1993. Forty-four of the
                     plants (62 percent) were positive for
                     Giardia, Cryptosporidium, or both at
                     one time or another (LeChevallier and
                     Norton 1995).
                      The oocyst recoveries and densities
                     reported by LeChevallier and Norton
                     (1995) are comparable to the results of
                     another survey of treated, untreated,
                     protected (pristine) and feces-
                     contaminated (polluted) water supplies
                     (Rose et al. 1991). Six of thirty-six
                     samples (17 percent) taken from potable
                     drinking water were positive for
                     Cryptosporidium, and concentrations in
                     these waters ranged from .5 to 1.7
                     oocysts/lOOL. In addition, a total of 188
                     surface water samples were analyzed
                     from rivers,  lakes, or springs in 17
                     States. The majority of surface water
                     samples were obtained from Arizona,
                     California, and Utah (126 samples in
all), with others from eastern States (28
samples), northwestern States (14
samples), southern States (13 samples),
midwestern States (6 samples), and
Hawaii (1 sample). Arithmetic average
oocyst concentrations ranged from less
than 1 to 4,400 oocysts/100 L,
depending on the type of water
analyzed. Cryptosporidium oocysts were
found in 55 percent of the surface water
samples at an average concentration of
43 oocysts/100 L.
  The LeChevallier and Norton (1995)
study collected the most  samples and
repeat samples from the most surface
water plants on a national level.
Therefore, the data from this study were
analyzed by EPA (EPA, 1998n) to
generate a distribution of source water
occurrence, presented  in Table II. 5.

TABLE 11.5.—BASELINE  EXPECTED NA-
  TIONAL        SOURCE      WATER
  CRYPTOSPORIDIUM  DISTRIBUTIONS
Percentile
25
50
75
90
95
Mean
Standard Deviation ....
Source
water
concentration
(oocysts/100L)
103
231
516
1064
1641
470
841
  Although limited by the small number
of samples per site (one to sixteen
samples; most sites were sampled five
times), the mean concentration at the 69

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                  Federal Register/Vol. 65, No.  69/Monday, April  10,  2000/Proposed Rules
                                                                    19057
sites from the eastern and central U.S.
seems to be represented by a lognormal
distribution.
  In addition to the source water data,
several studies have detected
Cryptosporidium oocysts in finished
water. The results of these studies have
been compiled in Table II.6.
         TABLE 11.6.—SUMMARY OF U.S. FINISHED WATER MONITORING DATA FOR CRYPTOSPORIDIUM OOCYSTS
Sample source
Filleted water ..... 	

Finished water 	
Finished water (clearwell)
Finished water (filter effluents)
Site 1 — Filter effluent
Site 2 — Filter effluent
Site 3 — Filter effluent
Finished water

Finished water 	
Finished water
Finished water 	
Number of
samples (n)
82
6
262
14
118
10
10
10
1 237
87
24
155
100
Samples posi-
tive for
Cryptosporidium
(percent)
27
33
13
14
26
70
10
10
7
10
"8
***13
2.5
15
Range of
oocyst cone.
(oocysts/
100L)
0.1^8 	
0 1-1 7
0.29-57 	
NR 	
NR
•\-4 	
0.5 	
2 	
NR 	
0-420
0-0.6 	
0.02-0.8 	
0.04-0.08 ....
Mean
i (oocysts/
100L)
i.5 	
02
33 (detect-
able).
NR 	
NR 	
NR 	
NA 	
NA 	
NR 	
NR 	
0.5 (g) 	
0.2 	
0.08 (g) 	
Reference
LeChevallier et al. 1991 a.
LeChevallier et al 1 992
LeChevallier and Norton 1995.
Consonery et al. 1992.
Consonery et al. 1992.
LeChevallier and Norton 1992.
LeChevallier and Norton 1 992.
LeChevallier and Norton 1992.
Rosen et al. 1996.
Stewart et al. 1997a.
States etal. 1997.
Consonery et al. 1997.
McTigue, etal. 1998.
  •Plants
  "Confirmed
  •"Presumed
  These studies show that despite some
treatment in place, Cryptosporidium
may still pass through the treatment
plant and into finished water.
  In general, oocysts are detected more
frequently and in higher concentrations
In rivers and streams than in lakes and
reservoirs (LeChevallier et al., 1991b;
Rose et al., 1988a,b). Madore et al.
(1987)  found high concentrations of
oocysts in a river affected by
agricultural runoff (5800 oocysts/L).
Such concentrations are especially
significant if the contaminant removal
process (e.g., sedimentation, filtration)
of the treatment plant is not operating
effectively. Oocysts may pass through to
the finished water, as LeChevallier and
Norton (1995) and several other
researchers also found, and infect
drinking water consumers.
E. Filter Backwash and Other Process
Streams: Occurrence and Impact
Studies
  Pathogenic microorganisms are
removed during the sedimentation and/
or filtration processes in a water
treatment plant. Recycle streams
generated during treatment, such as
spent filter backwash water,
sedimentation basin sludge, or thickener
supernatant are often returned to the
treatment train. These recycle streams,
therefore, may contain high
concentrations of pathogens, including
chlorine-resistant Cryptosporidium
oocysts. Recycle can degrade the
treatment process, especially when
entering the treatment train after the
rapid mix stage, by causing a chemical
imbalance, hydraulic surge and
potentially overwhelming the plant's
filtration capacity with a large
concentration of pathogens. High oocyst
concentrations found in recycle waters
can increase the risk of pathogens
passing through the treatment plant into
finished water.
  AWWA has compiled issue papers on
each of the following recycle  streams:
Spent filter backwash water,
sedimentation basin solids, combined
thickener supernatant, ion-exchange
regenerate, membrane concentrate,
lagoon decant, mechanical dewatering
device concentrate, monofill leachate,
sludge drying bed leachate, and small-
volume streams (e.g., floor, roof, lab
drains) (Environmental Engineering &
Technology, 1999). In addition, EPA
compiled existing occurrence data on
Cryptosporidium in recycle streams.
Through these efforts, Cryptosporidium
occurrence data has been found for
three types of recycle streams: Spent
filter backwash water, sedimentation
basin solids, and thickener supernatant.
  Nine studies have reported the
occurrence of Gryptosporidium for these
process streams. Each study's scope and
results are presented in Table II.7, and
brief narratives on each major study
follow the table. Note that the results of
the studies, if not presented in the
published report as oocysts/lOOL, have
been converted into oocysts/lOOL.
          TABLE 11.7.—CRYPTOSPORIDIUM OCCURRENCE IN FILTER BACKWASH AND OTHER RECYCLE STREAMS
Name/location of study
Drinking water treat-
ment facilities.
Number of
samples (n)
2 	

Type of sample
backflush waters from
rapid sand filters.
Cyst/oocyst concentration
sample 1: 26,000 oocysts/gal
(calc. as 686,900 oocysts/
100L).
sample 2: 92,000 oocysts/gal
(calc as 2,430,600 oocysts/
100L)
Number of
treatment
plants sampled
2 	

Reference
Rose etal. 1986.


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19058
Federal  Register/Vol. 65, No.  69/Monday, April 10, 2000/Proposed Rules
    TABLE 11.7.—CRYPTOSPORIDIUM OCCURRENCE IN FILTER BACKWASH AND OTHER RECYCLE STREAMS—Continued
Name/location of study
Thames, U.K., 	
Potable water supplies
in 17 States.
Name/location not re-
ported.
Bangor Water Treat-
ment Plant (PA).
Round 2: 1 (8-hour
composite).
Moshannon Valley
Water Treatment
Plant.
Plant "C" 	
Pittsburgh Drinking
Water Treatment
Plant.
"Plant Number 3"
"Plant C" (see Karanis
et al. 1996).
"Plant A" 	 	 ; 	

Number of
samples (n)
not reported .
not reported ....
not reported
Round 1: 1 (8-
hour com-
posite).
raw water
filter backwash
supernatant re-
cycle
Round 1' 1 (8-
hour com-
posite).
Round 2: 1 (8-
hour com-
posite).
1 1 samples
using contin-
uous flow
centrifuga-
tion;.
24 (two years
of monthly
samples).
riot reported
12
50
1

Type of sample
backwash water from
rapid sand filter.
filter backwash from
rapid sand filters (10
to 40 L sample vol.).
raw water
initial backwash water
raw water 	
filter backwash
supernatant recycle 6
oocysts/1 OOL.
140 oocysts/1 OOL
raw water
spent backwash 	
supernatant recycle 	
sludge 13 oocysts/
100L.
raw water
supernatant recycle 	
39 samples using car-
tridge filters.
filter backwash 	
raw water
spent backwash 	
raw water
backwash water from
rapid sand filters.
rapid sand filter (sam-
ple taken 10 min.
after start of
backwashing).
Cyst/oocyst concentration
Over 1 000 000 oocysts/1 OOL
in backwash water on 2/1 9/
89.
100,000 oocysts/1 OOL in su-
pernatant from settlement
tanks during the next few
days
217 oocysts/ 100 L (geometric
mean).
7 to 108 oocysts/1 OOL
detected at levels 57 to 61
times higher than in the raw
water.
902 oocysts/1 OOL

850 oocysts/1 OOL
16 613 oocysts/1 OOL

20 oocysts/1 OOL
backwash water from rapid
sand filters; samples col-
lected from sedimentation
basins during sedimentation
phase of backwash water at
depths of 1 , 2, 3, and 3.3 m.
328 oocysts/ 100 L (geometric
mean); (38 percent occur-
rence rate).
140 oocysts/1 OOL
avg 23 2 oocysts/1 OOL (max
109 oocysts/1 OOL) in 8 of 12
samples.
150 oocysts/1 OOL

Number of
treatment
plants sampled
1
not reported ....
not reported
141 oocysts/
100L 1

100L. 1
82 oocysts/
100L
420 oocysts/
100L. 1
flow: range 1
to 69
oocysts/1 00
L; 8 of 1 1
samples
positive.
non-detect-
13,158
oocysts/
100L. 1
100L.
avg 22 1
oocysts/1 OOL
(max. 257
oocysts/
1 0OL) in 41
of 50 sam-
ples

Reference
Colbourne 1989
Roseetal. 1991.
1991c.
Cornwell and Lee
1993

1993.
2 642 oocysts/1 OOL 1
Cornwell and Lee
1993.
1993.
0.8 to 252/1 OOL; 33
of 39 samples posi-
tive 1 Karanis et al.
1996.
States et al 1 997

1997.
1 Karanis et al 1 998



  The occurrence data available and
reported are primarily for raw and
recycle stream water. If filter backwash
enters the treatment train as a slug load
and disrupts the treatment process, it is
possible its effects would not be readily
seen in the finished water until several
minutes or hours after returning the
filter to service. In addition, the poor
recovery efficiencies of the IFA
Cryptosporidium detection method
                    complicate measurements in dilute
                    finished effluent waters.
                      As shown in Table II. 7, the
                    concentrations of oocysts in backwash
                    water and other recycle streams are
                    greater than the concentrations
                    generally found in raw water. For
                    example, four studies (Cornwell and
                    Lee, 1993; States et al., 1997; Rose et al.,
                    1986; and Colbourne, 1989] have
                    reported Cryptosporidium oocyst
                    concentrations in filter backwash water
exceeding 10,000 oocysts/lOOL. Such
concentrations illustrate that the
treatment plant has been removing
oocysts from the influent water during
the sedimentation and/or filtration
processes. As expected, the oocysts have
concentrated on the filters and/or in the
sedimentation basin sludge. Therefore,
the recycling of such process streams
(e.g., filter backwash, thickener
supernatant, sedimentation basin

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                  Federal  Register/Vol. 65, No. 69/Monday, April  10,  2000/Proposed Rules
                                                                    19059
sludge) re-introduces high
concentrations of oocysts to the
drinking water treatment train.
  Recycle can potentially return a
significant number of oocysts to the
treatment plant in a short amount of
time, particularly if the recycle is
returned to the treatment process
without prior treatment, equalization, or
some other type of hydraulic detention.
In addition, Di Giovanni, et al. (1999)
presented data indicating that viable
oocysts have been detected in filter
backwash samples using a cell culture/
polymerase chain reaction (PCR)
method. Cell culture is a test of the
viability/infectivity of the oocysts, while
PCR identified the cells infected by C.
parvum. Although recovery by IFA was
poor (6 to 8 percent for backwash
samples), 9 filter backwash recycle
samples were found to contain viable
and infectious oocysts, and the
infectious agent was determined to be
more than 98 percent similar in
structure to C. parvum. Should filter
backwash recycle disrupt normal
treatment operations or should
treatment not function efficiently due to
other deficiencies, high concentrations
of potentially viable, infectious oocysts
may pass through the plant into finished
drinking water. The recycle stream
occurrence studies presented in Table
U.7 are described in further detail in the
following sections.
Thames, U.K. Water Utilities Experience
with Cryptosporidium, Colbourne (1989)
   In response to a cryptosporidiosis
outbreak reported in February of 1989,
Thames Water undertook an
investigation of pathogen concentrations
within the Farmoor conventional
treatment plant's treatment train,
finished and raw \vaters. The
investigation occurred over a two month
period, from February to April 1989 and
included sampling of settled filter
backwash, the supernatant from spent
filter backwash, raw water, and water
sampled at the end of various Thames
distribution points.
   On February 19,1989 at the start of
the outbreak investigation, a
concentration of approximately
1,000,000 oocysts/lOOL was detected in
the filter backwash water. During the
first few days of the following
investigation, the supernatant of the
settled backwash water contained
approximately 100,000 oocysts/lOOL. At
the peak of the outbreak, thirty percent
of Thames' distribution system samples
were positive for oocysts, and ranged in
concentration from 0.2 to 7700 oocysts/
100L. Raw reservoir water contained
oocyst concentrations ranging from .2 to
1400 oocysts/lOOL. After washing the
filters twice in 24 hours, no oocysts
were found in the settled backwash
waters. Thames, U.K. Water Utilities
determined that a storm causing intense
precipitation and runoff resulted in
elevated levels of oocysts in the source
water which led to the high
concentrations of oocysts entering the
plant and subsequently deposited on the
filters and recycled as filter backwash.
Survey of Potable Water Supplies for
Cryptosporidium and Giardia, Rose, et
al., 1991
  In this survey, Rose, et al., collected
257 samples from 17 States from 1985
to 1988. The samples were collected on
cartridge filters and  analyzed using
variations of the IFA method. The
reported percent recovery for the
method was 29 to 58 percent. Filter
backwash samples were a subset of the
257,10 to 40 L samples were collected
from rapid sand filters.
  Rose, et al. reported the geometric
mean of the backwash samples at 217 -
Cryptosporidium oocysts/lOOL. This
was the highest reported average
Cryptosporidium concentration of any
of the water types tested, which
included polluted and pristine surface
and ground water sources, drinking
water sources in addition to filter
backwash recycle water.
Giardia and Cryptosporidium in Water
Supplies, LeChevallier, et al. (1991c)
  LeChevallier et al. conducted a study
to determine "whether compliance with
the SWTR would ensure control of
Giardia in potable water supplies." Raw
water and plant effluent samples were
collected from 66 surface water
treatment plants in 14 States and one
Canadian province,  although only
selected sites were tested for
Cryptosporidium oocysts in filter
backwash and settled backwash water.
  In the analysis of  pathogen
concentrations in the raw water and
filter backwash water of the water
treatment process, LeChevallier et al.
(1991c) found very high oocyst levels in
backwash water of utilities that had low
raw water parasite concentrations. The
pathogens were detected using a
combined IFA method that the authors
developed. Cryptosporidium levels in
the initial backwash water were 57 to 61
times higher than in the raw water
supplies. Raw water samples were
found to contain from 7 to 108 oocysts/
100L. LeChevallier et al. (1991c) also
noted that when Cryptosporidium were
detected in plant effluent samples (12 of
13 times), the organisms were also
observed in the backwash samples. The
study concluded that the consistency of
these results shows  that accumulation of
parasites in the treatment filters (and
subsequent release in the filter
backwash recycle water) could be
related to subsequent passage through
treatment barriers.

Recycle Stream Effects on Water
Treatment, Comwell and Lee (1993,
1994)

  The results described in Cornwell and
Lee's 1993 American Water Works
Association Research Foundation
Report and 1994 Journal of the
American Water Works Association
article on the Bangor and Moshannon
Valley, PA water treatment plants are
consistent with the results of States et
al. (1997). In total, Cornwell and Lee
investigated eight water treatment
plants, examining treatment efficiencies
including several recycle streams and
their impacts, and reporting a range of
pathogen and other water quality data.
All of the pathogen testing was
conducted using the EPA IFA method
refined by LeChevallier, et al. (1991c).
  Cornwell and Lee (1993) conducted
two rounds of sampling at both the
Bangor and Moshannon plants,
sampling the different recycle and
treatment streams as eight-hour
composites. They detected
Cryptosporidium concentrations of over
16,500 Cryptosporidium oocysts/lOOL,
in the backwash water at an adsorption
clarifier plant (Moshannon Valley) and
over 850 Cryptosporidium oocysts/lOOL
in backwash water from a direct
filtration plant (Bangor). The parasite
levels in the backwash samples were
significantly higher than concentrations
found in the raw source water, which
contained Cryptosporidium oocyst
concentrations of 13-20 oocysts/lOOL at
the Moshannon Valley plant and 6-140
oocysts/lOOL at the Bangor plant.
  In addition, Cornwell and Lee
determined oocyst concentrations for
two other recycle streams, combined  ,
thickener supernatant and
sedimentation basin solids. The
supernatant pathogen concentrations
were reported at 141 Cryptosporidium
oocysts/lOOL at the Bangor plant, and
levels were reported at 82 to 420
oocysts/lOOL for the Moshannon plant
in Rounds 1 and 2 of sampling,
respectively.  The sedimentation basin .
sludge was reported at 2,642         !
Cryptosporidium oocysts/lOOL in the
clarifier sludge from the Moshannon
Valley plant.

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Federal Register/Vol. 65, No. 69/Monday,  April 10, 2000/Proposed Rules
 Giardia and Cryptosporidium in
 Backwash Water from Rapid Sand
 Filters Used for Drinking Water, Karanis
 et al. (1996) and Distribution and
 Removal of Giardia and
 Cryptosporidium in Water Supplies in
 Germany Karanis, etal. (1998)

  Karanis et al. (1996 and 1998)
 conducted a four-year research study
 (samples collected from July, 1993-
 December, 1995) on the efficiency of
 Cryptosporidium removal by six
 different surface water treatment plants
 from Germany, all of which treat by
 conventional filtration. The method
 used was an IF A method dubbed the
 "EPA method", developed by
 Jakubowski and Ericksen, 1979.
  Karanis et al. (1996) detected
 Cryptosporidium in 82 percent of the
 samples of backwash water from  rapid
 sand filters of a water treatment plant
 ("Plant C") supplied by small rivers.
 Eight out of 12 raw water samples tested
 were positive for Cryptosporidium
 (range of 0.8 to 109 oocysts/lOOL).
 Backwash water samples collected by
 continuous flow centrifugation were
 positive for Cryptosporidium in 8 of 11
 samples (range of 1 to 69/100L). Of 39
 samples collected using cartridge filters,
 33 were positive for Cryptosporidium
 (range of 0.8 to 252/100L). The authors
 called attention to the high detection
 rate of Cryptosporidium in the
 backwash waters (82 percent) of Plant C
 and to the fact that the supernatant
 following sedimentation was not free
 from cysts and oocysts (Karanis et al.
 1996).
  In the 1998 publication, Karanis et al.
 compiled the data from the 1996  study
 with more backwash occurrence data
 collected from another treatment  plant
 ("Plant A"). The filter backwash of Plant
 A was sampled 10 minutes after the
 start of backwashing; and the backwash
 water was found to contain 150
 Cryptosporidium oocysts/lOOL.

 Protozoa in River Water: Sources,
 Occurrence, and Treatment, States, et
 al. (1997)

  Over a two year period (July, 1994-
 June, 1996), States et al. sampled
 monthly for Cryptosporidium in the
 raw, settled, filtered and filter backwash
 water at the Pittsburgh Drinking Water
 Treatment Plant, in order to gauge the
 efficiency of pathogen removal at the
 plant. States et al. identified several
 sources contributing oocysts to the
 influent water, including sewage  plant
 effluent, combined sewer overflows,
 dairy farm streams, and recycling of
backwash water. All pathogen sampling
was conducted with the IFA method.
                       Cryptosporidium occurred in the raw
                     Allegheny river water supplying the
                     plant with a geometric mean of 31
                     oocysts/lOOL in 63 percent of samples
                     collected, and ranged from non-detect to
                     2,333 oocysts/lOOL (see Table II.3 for
                     source water information). Of the filter
                     backwash samples, a geometric mean of
                     328 oocysts/lOOL was found at an
                     occurrence rate of 38 percent of
                     samples, with a range from non-detect
                     to 13,158 oocysts/lOOL. The fact that the
                     mean concentration of Cryptosporidium
                     oocysts in backwash water can be
                     substantially higher than the oocyst
                     concentration in untreated river water
                     suggests that recycling  untreated filter
                     backwash water can be a significant
                     source of this parasite to water within
                     the treatment process.

                     F. Summary and Conclusions
                       Cryptosporidiosis is a disease without
                     a therapeutic cure, and its causative
                     agent, Cryptosporidium, is resistant to
                     chlorine disinfection. Cryptosporidium
                     has been known to cause severe illness,
                     especially in immunocompromised
                     individuals, and can be fatal. Several
                     waterborne Cryptosporidiosis outbreaks
                     have been reported, and it is likely that
                     others have  occurred but have gone
                     unreported.  Cryptosporidium has been
                     detected in a wide range of source
                     waters,  documented in over 30 studies
                     from the literature, and it has been
                     found at levels of concern in filter
                     backwash water and other recycle
                     streams.
                      One of the key regulations EPA has
                     developed and implemented to counter
                     pathogens in drinking water is the
                     SWTR (54 FR 27486, June 19, 1989).
                     The SWTR requires that surface water
                     systems have sufficient treatment to
                     reduce the source water concentration
                     of Giardia and viruses by at least 99.9
                     percent (3 log) and 99.99 percent (4 log),
                     respectively. A shortcoming of the
                     SWTR, however, is that the rule does
                     not specifically control for
                     Cryptosporidium. The first report of a
                     recognized waterborne  outbreak caused
                     by Cryptosporidium was published
                     during the development of the SWTR
                     (D'Antonio et al. 1985).
                      In 1998, the Agency finalized the
                     IESWTR that enhances  the microbial
                     pathogen protection provided by the
                     SWTR for systems serving 10,000 or
                     more persons.  The IESWTR includes an
                     MCLG of zero for Cryptosporidium and
                    requires a minimum 2-log (99 percent)
                    removal of Cryptosporidium, linked to
                     enhanced combined filter effluent and
                     individual filter turbidity control
                    provisions.
                      Several provisions of today's
                    proposed rule, the LTlFBR, are
 designed to address the concerns
 covered by the IESWTR, improving
 control of Cryptosporidium and other
 microbial contaminants, for the portion
 of the public served by small PWSs (i.e.,
 serving less than 10,000 persons). The
 LTlFBR also addresses the concern that
 for all PWSs that practice recycling,
 Cryptosporidium (and other emerging
 pathogens resistant to standard
 disinfection practice) are reintroduced
 to the treatment process of PWSs by the
 recycle of spent filter backwash water,
 solids treatment residuals, and other
 process streams.
  Insufficient treatment practices have
 been cited as the cause of several
 reported waterborne disease outbreaks
 (Rose, 1997). Rose (1997) also found that
 a reduction in turbidity is indicative of
 a more efficient filtration process.
 Therefore, the turbidity and filter
 monitoring requirements of today's
 proposed LTlFBR will ensure that the
 removal process necessary to protect the
 public from Cryptosporidiosis is
 operating properly, and the recycle
 stream provisions will ensure that the
 treatment process is not disrupted or
 operating inefficiently. The LTlFBR
 requirements that address the potential
 for Cryptosporidium to enter the
 finished drinking water supply will be
 described in more  detail in the
 following sections.

 III. Baseline Information-Systems
 Potentially Affected By Today's
 Proposed Rule

  EPA utilized the 1997 state-verified
 version of the Safe Drinking Water
 Information System (SDWIS) to develop
 the total universe of systems which
 utilize surface water or groundwater
 under the direct influence  (GWUDI) as
 sources. This universe consists of
 11,593 systems serving fewer than
 10,000 persons, and 2,096 systems
 serving  10,000 or more persons. Given
 this initial baseline, the Agency
 developed estimates  of the number of
 systems which would be affected by
 components of today's proposed rule by
 utilizing three primary sources: Safe
 Drinking Water Information Systems;
 Community Water Supply  Survey; and
 Water: Stats. A brief overview of each  of
the data sources is  described in the
 following paragraphs.

 Safe Drinking Water Information System
 (SDWIS)

  SDWIS contains  information about
PWSs including violations of EPA's
regulations for safe drinking water.
Pertinent information in this database
includes system name and  ID,
population served, geographic location,

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                  Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
                                                                    19061

type of source water, and type of
treatment (if provided).
Community Water System Survey
(CWSS)
  EPA conducted the 1995 CWSS to
obtain data to support its development
and evaluation of drinking water
regulations. The survey consisted of a
stratified random sample of 3,700 water
systems nationwide (surface water and
groundwater). The survey asked 24
operational and 13 financial questions.
Waten/Stats (WaterStats)
  WaterStats is an in-depth database of
water utility information compiled by
the American Water Works Association.
The database consists of 898 utilities of
all sizes and provides a variety of data
including treatment information.
  Information regarding estimates of the
number of systems which may
potentially be affected by specific
components of today's proposed rule
can be found in the discussion of each
proposed rule component in Section IV.
IV. Discussion of Proposed LTlFBR
Requirements
A. Enhanced Filtration Requirements
  As discussed earlier in this preamble,
one of the key objectives of today's
proposed rule is ensuring that an
adequate level of public health
protection is maintained in order to
minimize the risk associated with
Cryptosporidium. While the current
SWTR provides protection from viruses
and Giardia, it does not specifically
address Cryptosporidium, which has
been linked to outbreaks resulting in
over 420,000 cases of gastrointestinal
illness in the 1990s (403,000 associated
with the Milwaukee outbreak). Because
of Cryptosporidium's resistance to
disinfection practices currently in place
at small systems throughout the        ,
country, die Agency believes enhanced
filtration requirements are necessary to
improve control of this microbial
pathogen.
  In the IESWTR, the Agency utilized
an approach consisting of three major
components to address Cryptosporidium
at plants serving populations of 10,000
or more. The first component required
systems to achieve a 2 log removal of
Cryptosporidium. The second          :
component consisted of strengthened
turbidity requirements for combined
filter effluent. The third component
required individual filter turbidity
monitoring.
  In today's proposed rule addressing
systems serving fewer than 10,000
persons, the Agency is utilizing the
same framework. Where appropriate,
EPA has evaluated additional options in
an effort to alleviate burden on small
systems while still maintaining a
comparable level of public health
protection.
  The following sections describe the
overview and purpose of each of the
rule components, relevant data utilized
during development, the requirements
of today's proposed rule (including
consideration of additional options
where appropriate), and a request for
comment regarding each component.

1. Two Log Cryptosporidium Removal
Requirement
a. Two Log Removal
i. Overview and Purpose
  The 1998 IESWTR (63 FR 69477,
December 16,1998) establishes an
MCLG of zero for Cryptosporidium in
order to adequately protect public
health. In conjunction with the MCLG,
the IESWTR also established a treatment
technique requiring 2 log
Cryptosporidium removal for all surface
water and GWUDI systems which filter  ,
and serve populations of 10,000 or more
people, because it was not economically
and technologically feasible to
accurately ascertain the level of
Cryptosporidium using current
analytical methods. The Agency
believes it is appropriate and necessary
to extend this treatment technique of 2
log Cryptosporidium removal
requirement to systems serving fewer
than 10,000 people.

ii. Data

  As detailed later in this section, EPA
believes that the data and principles
supporting requirements established for
systems serving populations of 10,000
or more are also applicable to systems
serving populations fewer than  10,000.
The following section provides
information and data regarding: (1) the
estimated number of small systems
subject to the proposed 2 log
Cryptosporidium removal requirement;
and (2) Cryptosporidium removal using
various filtration technologies.

Estimate of the Number of Systems
Subject to 2 log Cryptosporidium
Removal Requirement

  Using the baseline described in
Section III of today's proposed rule, the
Agency applied percentages of surface
water and GWUDI systems which filter
(taken from the 1995 CWSS) in order to
develop an estimate of the number of
systems which filter and serve fewer
than 10,000 persons. This resulted in an
estimated 9,133 surface water and
GWUDI systems that filter which may
be subject to the proposed removal
requirement. Table IV. 1 provides this
estimate broken down by system size
and type.
         TABLE IV.1 .—ESTIMATE OF SYSTEMS SUBJECT TO 2 LOG CRYPTOSPORIDIUM REMOVAL REQUIREMENT3
System type
Community 	 	 	 	 	 	 	 	
Non Community 	 	 	
NTNC 	 	 	
Total 	
Population served
<100
888
1099
214
2201
101-500
1453
374
204
2031
501-1K"
950
' 78
I 82
' 1110
1K-3.3K>>
2022
64
64
2150
3.3K-10Ki>
1591
35
17
1643
Total #Sys.
6903
16491
581
»9134b
  •Numbers may not add due to rounding
  bK = thousands                                                                                                  •

                          Cryptosporidium Removal Using Conventional and Direct Filtration

    During development of the LTlFBR, the Agency reviewed the results of several studies that demonstrated the ability
 of conventional and direct filtration systems to achieve 2 log removal of Cryptosporidium at well operated plants achieving
 low turbidity levels.  Table IV.2 provides key information  from these  studies. A brief description of each study follows
 the table.

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Federal Register/Vol. 65,  No. 69/Monday, April 10, 2000/Proposed  Rules
                        TABLE IV.2.—CONVENTIONAL AND DIRECT FILTRATION REMOVAL STUDIES
 Type of treatment
           Log removal
        Experimental design
                                                                                                  Researcher
Conventional
Direct filtration
Rapid Granular Fil-
  tration (alone).
 Cryptosporidium 4.2-5.2 .
 Giardia 4.1-5.1 	
 Cryptosporidium 1.9-4.0 .
 Giardia 2.2-3.9	
 Cryptosporidium 1.9-2.8 .
 Giardia 2.8-3.7	
 Cryptosporidium 2.3-2.5 .
 Giardia 2.2-2.8	
 Cryptosporidium 2-3 	
 Giardia and Crypto 1.5-2

 Cryptosporidium 4.1-5.2 .
 Cryptosporidum .2-1.7 .....
 Cryptosporidium 2.7-3.1
 Giardia 3.1-3.5	
 Cryptosporidium 2.7-5.9
 Giardia 3.4-5.0	
 Cryptosporidium 1.3-3.8
 Giardia 2.9-4.0	
 Cryptosporidium 2-3 	
 Cryptosporidium 2.3-4.9
                   Giardia 2.7-5.4
Pilot plants	
Pilot plants	
Pilot-scale plants 	
Pilot-scale plants 	
Full-scale plants 	
Full-scale plants 	
Full-scale plants 	
Full-scale plants 	
Pilot plants	
Full-scale plant (operation considered
  not optimized).
Pilot Plant (optimal treatment) 	
Pilot Plant (suboptimal treatment) 	
Pilot plants
Pilot plants
Pilot plants
Pilot plants
Pilot plants
Pilot plants
Pilot plants
Pilot plant .
Patania et al. 1995
Patania et al. 1995
Nieminski/Ongerth 1995
Nieminski/Ongerth 1995
Nieminski/Ongerth 1995
Nieminski/Ongerth 1995
LeChevallier and Norton 1992

LeChevallier and Norton 1992
Foundation for Water Research, Britain
  1994
Kelley etal. 1995
Dugan et al. 1999
Dugan et al. 1999
Ongerth/Pecaroro 1995
Ongerth/Pecaroro 1995
Patania et al. 1995
Patania ef al. 1995
Nieminski/Ongerth 1995
Nieminski/Ongerth 1995
West etal.  1994
Swertfeger et al., 1998
Patania, NancyL, etal. 1995

  This study consisted of four pilot
studies which evaluated treatment
variables for their impact on
Cryptosporidium and Giardia removal
efficiencies. Raw water turbidities in the
study ranged between 0.2 and 13 NTU.
When treatment conditions were
optimized for turbidity and particle
removal at four different sites,
Cryptosporidium removal ranged from
2.7 to 5.9 log and Giardia removal
ranged from 3.4 to 5.1 log during stable
filter operation. The median turbidity
removal was 1.4 log, whereas the
median particle removal was 2 log.
Median oocyst and cyst removal was 4.2
log. A filter effluent turbidity of 0.1
NTU or less resulted in the most
effective cyst removal, up to 1 log
greater than when filter effluent
turbidities were greater than 0.1 NTU
(within the 0.1 to 0.3 NTU range).
Cryptosporidium removal rates of less
than 2.0 log occurred  at the end of the
filtration cycle.                    '•

Nieminski, Eva C. and Ongerth, ferry E.
1995

  This 2-year study evaluated Giardia
and Cryptosporidium cyst removal
through direct and conventional
filtration.  The source  water of the full
scale plant had turbidities typically
between 2.5 and 11 NTU with a
maximum of 28 NTU. The source water
of the pilot plant typically had
turbidities of 4 NTU with a maximum
of 23 NTU. For the pilot plant achieving
filtered water turbidities between 0.1—
                      0.2 NTU, Cryptosporidium removals
                      averaged 3.0 log for conventional
                      treatment and 3.0 log for direct
                     .filtration, while the respective Giardia
                      removals averaged 3.4 log and 3.3 log.
                      For the full scale plant achieving similar
                      filtered water turbidities,
                      Cryptosporidium removal averaged 2.25
                      log for conventional treatment and 2.8
                      log for direct filtration, while the
                      respective Giardia removals averaged
                      3.3 log for conventional  treatment and
                      3.9 log for direct filtration. Differences
                      in performance between direct filtration
                      and conventional treatment by the full
                      scale plant were attributed to
                      differences in source water quality
                      during the filter runs.

                      Ongerth, ferry E. and Pecaroro, f.P. 1995
                       A 1 gallon per minute (gpm) pilot
                      scale water filtration plant was used to
                      measure removal efficiencies of
                      Cryptosporidium and Giardia using very
                      low turbidity source waters (0.35 to 0.58
                      NTU). With optimal coagulation, 3 log
                      removal for both pathogens were
                      obtained. In one test run, where
                      coagulation was intentionally sub-
                      optimal, the removals were only 1.5 log
                      for Cryptosporidium and 1.3 log  for
                      Giardia. This demonstrates the
                      importance of proper coagulation for
                      cyst removal even though the effluent
                      turbidity was less than 0.5 NTU.

                      LeChevallier, Mark W. and Norton,
                      William D. 1992
                       The purpose of this study was to
                      evaluate the relationships among
                      Giardia, Cryptosporidium, turbidity,
                            and particle counts in raw water and
                            filtered water effluent samples at three
                            different systems. Source water
                            turbidities ranged from less than 1 to
                            120 NTU. Removals of Giardia and
                            Cryptosporidium (2.2 to 2.8 log) were
                            slightly less than those reported by
                            other researchers, possibly because full
                            scale plants were studied under less
                            ideal conditions than the pilot plants.
                            The participating treatment plants
                            operated within varying stages of
                            treatment optimization. The median
                            removal achieved was 2.5 log for
                            Cryptosporidium and Giardia.

                            LeChevallier, Mark W.; Norton, William
                            D.; and Lee, Raymond G. 199lb
                              This study evaluated removal
                            efficiencies for Giardia and
                            Cryptosporidium in 66 surface water
                            treatment plants in 14 States and 1
                            Canadian province. Most of the utilities
                            achieved between 2 and 2.5 log
                            removals for both Giardia and
                            Cryptosporidium. When no oocysts
                            were detected in the finished water,
                            occurrence levels were assumed at the
                            detection limit for calculating removal
                            efficiencies.

                            Foundation for Water Research 1994
                              This study evaluated
                            Cryptosporidium removal efficiencies
                            for several treatment processes
                            (including conventional filtration) using
                            a pilot plant and bench-scale testing.
                            Raw water turbidity ranged from 1 to 30
                            NTU.  Cryptosporidium  oocyst removal
                            was between 2 and 3 log using
                            conventional filtration.  Investigators

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                  Federal Register/Vol.  65,  No. 69/Monday,  April 10, 2000/Proposed  Rules
                                                                     19063
concluded that any measure which
reduced filter effluent turbidity should
reduce risk from Cryptosporidium, and
also showed the importance of selecting
proper coagulants, dosages, and
treatment pH. In addition to turbidity,
increased color and dissolved metal ion
coagulant concentration in the effluent
are indicators of reduced efficiency of
coagulation/flocculation and possible
reduced oocysts removal efficiency.
Kelley, M.B. et al. 1995
  This study evaluated two U.S. Army
installation drinking water treatment
systems for the removal of Giardia and
Cryptosporidium. Protozoa removal was
between 1.5 and 2 log. The authors
speculated that this low
Cryptosporidium removal efficiency
occurred because the coagulation
process was not optimized, although the
finished water turbidity was less than
0.5 NTU.
West, Thomas; et al. 1994
  This study evaluated the removal
efficiency of Cryptosporidium through
direct filtration using anthracite mono-
media at filtration rates of 6 and 14
gpm/sq.ft. Raw water turbidity ranged
from 0.3 to 0.7 NTU. Removal
efficiencies for Cryptosporidium at both
filtration rates were 2 log during filter
ripening (despite turbidity exceeding
0.2 NTU), and 2 to 3 log for the stable
filter run. Log removal declined
significantly during particle
breakthrough. When effluent turbidity
was less than 0.1 NTU, removal
typically exceeded 2 log. Log removals
of Cryptosporidium generally exceeded
that for particle removal.
Swertfeger et al., 1998
  The Cincinnati Water Works
conducted a 13 month pilot study to
determine the optimum filtration media
and depth of the media to replace media
at its surface water treatment plant. The
study investigated cyst and oocyst
removal through filtration alone
(excluding chemical addition, mixing,
or sedimentation) and examined sand
media, dual media, and deep dual
media. Cyst and oocyst removal by each
of the media designs was > 2.5 log by ;
filtration alone.

Duganetal, 1999
  EPA conducted pilot scale
experiments to assess the ability of
conventional treatment to control
Cryptosporidium oocysts under steady
state conditions. The work was
performed with a pilot plant designed to
minimize flow rates and the number of
oocysts required for spiking. With
proper coagulation control, the
conventional treatment process
achieved at least 2 log removal of
Cryptosporidium. In all cases where 2
log removal was not achieved, the plant
also did not comply with the IESWTR
filter effluent turbidity requirements.
  All of the studies described above
indicate that rapid granular filtration,
when operated under appropriate
coagulation conditions and optimized to
achieve a filtered water turbidity level
of less than 0.3 NTU, should achieve at
least 2 log of Cryptosporidium removal.
Removal rates vary widely, up to almost
6 log, depending upon water matrix
conditions, filtered water turbidity
effluent levels, and where and when
removal efficiencies are measured
within the filtration cycle. The highest
log pathogen removal rates occurred in
those pilot plants and systems which
achieved very low finished water
turbidities (less than 0.1 NTU). Other
key points related to the studies
include:
  • As turbidity performance improves
for treatment of a particular water, there
tends to be greater removal of
Cryptosporidium.
  • Pilot plant study data in particular
indicate high likelihood of achieving at
least 2 log removal when plant
operation is optimized to achieve low
turbidity levels. Moreover, pilot studies
represented in Table IV.2.a tend to be,
for low-turbidity waters, which are
considered to be the most difficult to
treat regarding particulate removal and
associated protozoan removal.
  • Because high removal rates were
demonstrated in pilot studies using
lower-turbidity source waters, it is
likely that similar or higher removal
rates can be achieved for higher-
turbidity source waters.
  • Determining Cryptosporidium
removal in full-scale plants can be
difficult due to the fact that data
includes many non-detects in the
finished water. In these cases, finished
water concentration levels are assigned
at the detection limit and are likely to
result in over-estimation of oocysts in
the finished water. This tends to under-
estimate removal levels.
  • Another factor that contributes to
differences among the data is that some
of the full-scale plant data comes from
plants that are not optimized, but meet
existing SWTR requirements. In such
cases, oocyst removal may be less than
2 log. In those studies that indicate that
full-scale plants are achieving greater
than 2 log removal (LeChevallier studies
in particular), the following
characteristics pertain:
—Substantial numbers of filtered water
    measurements resulted in oocyst
    detections;
—Source water turbidity tended to be
    relatively high compared to some of
    the other studies; and
—A significant percentage of these
    systems were also achieving low
    filtered water turbidities,
    substantially less than 0.5 NTU.
  •Removal of Cryptosporidium can
vary significantly in the course of the
filtration cycle (i.e., at the start-up and
end of filter operations versus the stable
period of operation).

Cryptosporidium Removal Using Slow
Sand and Diatomaceous Earth Filtration

  During development of the IESWTR,
the Agency also evaluated several
studies which demonstrated that slow
sand and diatomaceous earth filtration
were capable of achieving at least 2 log
removal of Cryptosporidium. Table IV. 3
provides key information from these
studies. A brief description of each
study follows the table.
                 TABLE IV.3— SLOW SAND AND DIATOMACEOUS EARTH FILTRATION REMOVAL STUDIES
Type of treatment





Log removal


Giardia & Cryptosporidium > 3
Cryptosporidium 3 3—6 68

Experimental design
Pilot plant at 4 5 to 16 5°C
Full-scale plant 	 	 	
Pilot plant 	 	 	 	
Bench scale 	

Researcher
Shuler and Ghosh 1991.
imms et. al. 1995.
Shuler et. al. 1990.
Ongerth & Hutton, 1997.

Shuler and Ghosh 1991

  This pilot study was conducted to
evaluate the ability of slow sand filters
to remove Giardia, Cryptosporidium,
coliforms, and turbidity. The pilot study
was conducted at Pennsylvania State
University using a raw water source
with a turbidity ranging from 0.2-0.4
NTU. Influent concentration of

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19064
Federal Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed Rules
Cryptosporidium oocysts during the
pilot study ranged from 1,300 to 13,000
oocysts/gallon. Oocyst removal was
shown to be greater than 4 log.
Timms et al 1995
  This pilot study was conducted to
evaluate the efficiency of slow sand
filters at removing Cryptosporidium. A
pilot plant was constructed of 1.13 m2
in area and 0.5 m in depth with a
filtration rate of 0.3m/h. The filter was
run for 4—5 weeks before the experiment
to ensure proper operation.
Cryptosporidium oocysts were spiked to
a concentration of 4,000/L. Results of
the study indicated a 4.5 log removal of
Cryptosporidium oocysts.
Shuler et al 1990
  In this study, diatomaceous earth (DE)
filtration was evaluated for removal of
Giardia, Cryptosporidium, turbidity and
coliform bacteria. The study used a
O.lm2 pilot scale DE filter with three
grades of diatomaceous earth (A, B, and
C). The raw water turbidity varied
between 0.1 and 1 NTU. Filter runs
ranged from 2 days to 34 days. A greater
than 3 log removal of Cryptosporidium
was demonstrated in the 9 filter runs
which made up the study.
Ongerth and Hutton, 1997
  Bench scale studies were used to
define basic characteristics of DE
filtration as a function of DE grade and
filtration rate. Three grades of DE were
used in the tests. Cryptosporidium
removal was measured by applying river
water seeded with Cryptosporidium to
Walton test filters. Tests were run for
filtration rates of 1 and 2 gpm/sq ft.
                     Each run was replicated 3 times.
                     Approximately 6 logs reduction in the
                     concentration of Cryptosporidium
                     oocysts was expected under normal
                     operating conditions.

                     Cryptosporidium Removal Using
                     Alternative Filtration Technologies

                       EPA recognizes that systems serving
                     fewer than 10,000 individuals employ a
                     variety of filtration technologies other
                     than those previously discussed. EPA
                     collected information regarding several
                     other popular treatment techniques in
                     an effort to verify that these treatments
                     were also technically capable of
                     achieving a 2 log removal of
                     Cryptosporidium. A brief discussion of
                     these alternative technologies follows
                     along with studies demonstrating
                     effective Cryptosporidium removals.

                     Membrane Filtration

                       Membrane filtration (Reverse
                     Osmosis, Nanofiltration, Ultrafiltration,
                     and Microfiltration) relies upon pore
                     size in order to remove particles from
                     water. Membranes possess a pore size
                     smaller than that of a Cryptosporidium
                     oocyst, enabling them to achieve
                     effective log removals. The smaller the
                     pore size, the more effective the rate of
                     removal. Typical pore sizes for each of
                     the four types of membrane filtration are
                     shown below:
                       •  Microfiltration—1-0.1 microns
                     (am)
                       •  Ultrafiltration—0.1-.01 (urn)
                       •  Nanofiltration—.01-.001 (urn)
                       •  Reverse Osmosis—<.001 (urn)
Bag Filtration
  Bag filters are non-rigid, disposable,
fabric filters where water flows from
inside of the bag to the outside of the
bag. One or more filter bags are
contained within a pressure vessel
designed to facilitate rapid change of the
filter bags when the filtration capacity
has been used up. Bag filters do not
generally employ any chemical
coagulation. The pore sizes in the filter
bags designed for protozoa removal
generally are small enough to remove
protozoan cysts and oocysts but large
enough that bacteria, viruses and fine
colloidal clays would pass through. Bag
filter studies have shown a significant
range of results in the removal of
Cryptosporidium oocysts (0.33-3.2 log).
(Goodrich, 1995)

Cartridge Filtration
  Cartridge filtration also relies on
physical screening to remove particles
from water. Typical cartridge filters are
pressure filters with glass, fiber or
ceramic membranes, or strings wrapped
around a filter element housed in a  '
pressure vessel (USEPA, 1997a).
  The Agency evaluated several studies
which demonstrate the ability of various
alternative filtration technologies to
achieve 2 log removal of
Cryptosporidium (in several studies 2
log removal of 4-5 (um) microspheres
were used as a surrogate for
Cryptosporidium). These studies
demonstrate that 2 log removal was
consistently achievable in all but bag
filters. Table IV.4 provides key
information from these studies. A brief
description of each study follows:
                              TABLE IV.4.—ALTERNATIVE FILTRATION REMOVAL STUDIES
Type of treatment
Microfiltration 	





Ultrafiltration 	 '....






Reverse Osmosis ....
Hybrid Membrane ...
Bag Filtration 	
Cartridge filtration ....


Log removal
Cryptosporidium 4.2—4.9 log . .. .
Giardia 4.6—5.2 log 	
Cryptosporidium 6.0 — -7.0 log 	
Cryptosporidium 4.3 — 5.0 log 	
Cryptosporidium 7.0—7 7 log
Microspheres 3 57—3 71 log
Cryptosporidium 4.4 — 4.9 log 	
Giardia 4 7-5 2 log
Cryptosporidium 5.73—5.89 log 	
Giardia 5.75— 5.85 log 	
Cryptosporidium 7.1—7.4 log 	
Cryptosporidium 3.5 log 	
Microspheres 3—4 log
Cryptosporidium > 5 7 log
Giardia > 5.7 log.
Microspheres 4.18 log 	
Microspheres .33—3 2 log .
Microspheres 3.52-3.68 log 	
Particles (5—1 5 um) > 2 log

Experimental design
Bench Scale

Pilot Plant 	
Pilot Plant 	
Bench Scale
Full Scale
Bench Scale

Bench Scale 	

Bench Scale
pilot Plant

Pilot Scale
Bench Scale
Pilot Plant
Pilot Plant 	
Bench Scale

Researcher
Jacangelo et al 1997


Drozd & Schartzbrod 1 997
Hirata & Hashimoto 1998
Goodrich et al 1995 ' >
Jacangelo et al 1997 •

Collins ef al 1996

Hirata & Hashimoto 1998
Lykins et al 1 994 •

Adham et al 1998
Goodrich et al 1995
Goodrich et al 1995
Goodrich et al 1995
Land 1998


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                  Federal  Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
                                                                    19065
Jacangelo et al., 1997

  Bench scale and pilot plant tests were
conducted with microfiltration and
ultrafiltration filters (using six different
membranes) in order to evaluate
microorganism removal. Bench scale
studies were conducted under worst
case operating conditions (direct flow
filtration at the maximum recommended
transmembrane pressure using
deionized water slightly buffered at pH
7). Log removal ranged from 4.7 to 5.2
log removal. Pilot plant results ranged
from 6.0—7.0 log removal during worst-
case operating conditions (i.e., direct
filtration immediately after backwashing
at the maximum recommended
operating transmembrane pressure).

DrozdandSchartzbrod, 1997

  A pilot plant system was established
to evaluate the removal of
Cryptosporidium using crossflow
microfiltration (.2 um porosity). Results
demonstrated Cryptosporidium log
removals of 4.3  to greater than 5.5 with
a corresponding mean filtrate turbidity
of0.25NTU.
Collins et. al., 1996

  This study consisted of bench scale
testing of Cryptosporidium and Giardia
log removals using an ultrafiltration
system.  Log removal of Cryptosporidium
ranged from 5.73 to 5.89 log, while
removal of Giardia ranged from 5.75 to
5.85 log.
Hirata G-Hashimoto, 1998

  Pilot scale testing using
microfiltration (nominal pore size of .25
um) and ultrafiltration (nominal cut-off
molecular weight (MW) 13,000 daltons)
was conducted to determine
Cryptosporidium oocyst removal.
Results  conducted on the ultrafiltration
units ranged from 7.1 to 7.5 logs of
Cryptosporidium removal. Results of the
microfiltration studies yielded log
removals from 7.0 to 7.7 log.

Lykirts et al., [1994]

  An ultrafiltration system was
evaluated for the removal of
Cryptosporidium oocysts at the USEPA
Test and Evaluation Facility in
Cincinnati, Ohio. The filter run was just
over 48  hours. A 3.5 log removal of
Cryptosporidium oocysts was observed.
Additionally, twenty-four experiments
were performed using 4.5 um
polystyrene microspheres as  a surrogate
for Cryptosporidium because of a
similar particle  distribution. Log
removal of microspheres ranged from 3
to 4 log.
Adham et al., 1998
  This study was conducted to evaluate
monitoring methods for membrane
integrity. In addition to other activities,
microbial challenge tests were
conducted on reverse osmosis (RO)
membranes to both determine log
removals and evaluate system integrity.
Log removal of Cryptosporidium and '.
Giardia was >5.7 log in uncompromised
conditions, and > 4.5 log in
compromised conditions.

Goodrich et al., 1995
  This study was conducted to evaluate
removal efficiencies of three different
bag filtration systems. Average filter
pore size of the filters was 1 um while
surface area ranged from 35 to 47 sq ft.
Bags were operated at 25, 50 and 100
percent of their maximum flow rate
while spiked with 4.5 um polystyrene
microspheres (beads) as a surrogate for
Cryptosporidium. Bead removal ranged
from .33 to 3.2 log removal.

Goodrich et al 1995.
  This study evaluated a cartridge filter
with a 2 um rating and 200 square feet
of surface area for removal  efficiency of
Cryptosporidium sized particles. The
filter was challenge tested with 4.5 um
polystyrene microspheres as a surrogate
for Cryptosporidium. Flow was set at 25
gpm with 50 psi at the inlet. Results
from two runs under the same
conditions exhibited log removals of
3.52 and 3.68.

Land, 1998
  An alternative technology
demonstration test was conducted to
evaluate the ability of a cartridge filter
to achieve 2 log removal of particles in
the 5 to 15 um range. The cartridge
achieved at least 2 log removal of the 5
to 25 um particles 95 percent of the time
up to a 20 psi pressure differential. The
filter achieved at least 2 log removal of
5 to 15 um particles up to 30-psi
pressure differential.
  While the studies above note that
alternative filtration technologies have
demonstrated in the lab the capability to
achieve a 2 log removal of
Cryptosporidium, the Agency believes
that the proprietary nature  of these
technologies necessitates a more
rigorous technology-specific
determination be made. Given this
issue, the Agency believes that its
Environmental Technology Verification
(ETV) Program can be utilized to verify
the performance of innovative
technologies. Managed by EPA's Office
of Research and Development, ETV was
created to substantially accelerate the,
entrance of new environmental
technologies into the domestic and
international marketplace. ETV consists
of 12 pilot programs, one of which
focuses on drinking water. The program
contains a protocol for physical removal
of microbiological and particulate
contaminants, including test plans for
bag and cartridge filters and membrane
filters (NSF, 1999). These protocols can
be utilized to determine whether a
specific alternative technology can
effectively achieve a 2 log removal of
Cryptosporidium, and under what
parameters that technology must be
operated to ensure consistent levels of
removal. Additional information on the
ETV program can be found on the
Agency's website at http://
www.epa.gov/etv.

iii. Proposed Requirements
  Today's proposed rule establishes a
requirement for 2 log removal of
Cryptosporidium for surface water and
GWUDI systems serving fewer than
10,000 people that are required to filter
under the SWTR. Compliance with the
combined filter effluent turbidity
requirements, as described later, ensures
compliance with the 2 log removal
requirement. The requirement for a 2 log
removal of Cryptosporidium applies
between a point where the raw water is
not subject to recontamination by
surface water runoff and a point
downstream before or at the first      ;
customer.
iv. Request for Comments
  EPA requests comment on the 2 log
removal requirement as discussed. The
Agency is also soliciting public
comment and data on the ability of
alternative filtration technologies to
achieve 2 log Cryptosporidium removal.

2. Turbidity Requirements
a. Combined Filter Effluent
i. Overview and Purpose
  In order to address concern with
Cryptosporidium, EPA has analyzed log
removal performance by well operated
plants  (as described in the previous
section) as well as filter performance
among small systems to develop an
appropriate treatment technique
requirement that assures an increased
level of Cryptosporidium removal. In  ,
evaluating combined filter performance
requirements, EPA considered the
strengthened turbidity provisions
within the IESWTR and evaluated     ',
whether these were appropriate for
small systems as well.

ii. Data
  In an effort to evaluate combined filter
effluent (CFE) requirements, EPA
collected data in several areas to

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 19066
Federal Register/Vol.  65,  No. 69/Mpnday, April 10, 2000/Proposed Rules
 supplement existing data, and address
 situations unique to smaller systems.
 This data includes: .
 .  • An estimate of the number of ,
 systems subject to the proposed
 strengthened turbidity requirements;
   • Current turbidity levels at systems
 throughout the U.S. serving populations
 fewer than 10,000; \
   • The ability of package plants to
 meet strengthened turbidity standards;
 and
   • The correlation between meeting
 CFE requirements and achieving 2 log
 removal of Cryptosporidium.
 Estimate of the Number of Systems
 Subject to Strengthened CFE Turbidity
 Standards
   Using the estimate of 9,134 systems
 which filter and serve fewer than 10,000
 persons (as described in Section IV.A.I
i of today's proposal), the Agency used
 the information contained within 'the
 CWSS database to estimate the number
 of systems which utilized specific types
 of filtration. The data was segregated
 based on the type  of filtration utilized
 and the population size of the system.
 Percentages were derived for each of the
 following types of filtration:
   • Conventional and Direct Filtration;
   • Slow Sand Filtration;
   • Diatomaceous Earth Filtration; and
   • Alternative Filtration Technologies.
   The percentages were applied to the
 estimate discussed in Section IV.A.I of
 today's proposal for each of the
 respective population categories. Based
 on this .analysis, the Agency estimates
 5,896 conventional and direct filtration
 systems will be subject to the
 strengthened combined filter effluent
 turbidity standards. EPA estimates 1,756
 systems utilize slow sand or
 diatomaceous earth filtration, and must
 continue to meet turbidity standards set
 forth in the SWTR. The remaining 1,482
 systems are estimated to use alternative
 filtration technologies and will be
 required to meet turbidity standards as
                     set forth by the State upon analysis of
                     a 2 log Cryptosporidium demonstration
                     conducted by the system.
                     Current Turbidity Levels
                       EPA has developed a data 'set which
                     summarizes the historical turbidity
                     performance of various filtration plants
                     serving populations fewer than 10,000
                     (EPA, 1999d). The data set represents
                     those systems that were in compliance
                     with the turbidity requirements of the
                     SWTR during all months being
                     analyzed. The data set consists of 167
                     plants from 15 States. Table IV.5
                     provides information regarding the
                     number of plants from each State. The
                     data set includes plants representing
                     each of the five population groups
                     utilized in the CWSS (25-100,101-500,
                     501-1,000,1,001-3,300, and 3,301-
                     10,000). The Agency has also received
                     an additional data set from the State of
                     California (EPA, 2000). This data has
                     not been included'in the assessments
                     described below. The California data
                     demonstrates similar results to the
                     larger data set discussed below.

                      TABLE IV.5.—SUMMARY OF LT1FBR
                              TURBIDITY DATA SET
State
Alabama 	
California
Colorado 	
Illinois
Kansas

Minnesota 	
Montana .. . ....
North Carolina 	 , 	
Ohio
Pennsylvania 	
South Carolina 	
Texas
Washington 	 :..........
West Virginia

Total 	
Number of
Plants
1
1
16
13
20
6
3
2
16
4
27
16
, 23
17
2

167
  This data was evaluated to assess the
national impact of modifying existing
turbidity requirements. The current
performance of plants was assessed with
respect to the number of months'in
which selected 95th percentile and
maximum turbidity levels were met.
The data show that approximately 88
percent of systems are also Currently
meeting the new requirements of a
maximum turbidity limit of 1 NTU
(Figure IV.l). With respect to the 95th
percentile turbidity limit, roughly 46
percent of these systems are currently
meeting the new requirement of 0.3
NTU (Figure IV. 2) while approximately
70 percent meet this requirement 9
months out of the year. Estimates for
systems needing to make changes to
meet a turbidity performance limit of
0.3 NTU were based on the ability of
systems currently to meet a 0.2 NTU.
This assumption was intended to take
into account a utility's concern with
possible turbidity measurement error
and to reflect the expectation that a
number of utilities will attempt to
achieve finished water turbidity levels
below the  regulatory performance level
to assure compliance.
  As depicted in Figure IV.l and IV.2,
the tighter turbidity performance
standards for combined filter effluent in
today's proposed rule reflect the actual,
current performance many systems
already achieve nationally. Revising the
turbidity criteria effectively ensures that
these  systems continue to perform at
their current level while also improving
performance of a substantial number of
systems that currently meet existing
SWTR criteria, but operate at turbidity
levels higher than proposed in today's
rule.
BILLING CODE 6560-50-P
                       (EPA, 1999d)

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   Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19067
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                  Federal Register/Vol.  65,  No. 69/Monday, April  10, 2000/Proposed Rules
                                                                     19069
Package Plants
  During development of today's
proposed rule, some stakeholders
expressed concern regarding the ability
of "package plants" to meet the
proposed requirements. EPA evaluated
these systems by gathering data from
around the country. The information
affirms the Agency's belief that package
plants can and currently do meet the
turbidity limits in today's proposed
rule.
  Package plants combine the processes
of rapid mixing, flocculation,
sedimentation and filtration (rapid sand,
mixed or dual media filters) into a
single package system. Package
Filtration Plants are preconstructed,
skid mounted and transported virtually
assembled to the site. The use of tube
settlers, plate settlers, or adsorption
clarifiers in some Package Filtration
Plants results in a compact size and
more treatment capacity.
  Package Filtration Plants  are
appropriate for treating water of a fairly
consistent quality with low to moderate
turbidity. Effective treatment of source
waters containing high levels of or
extreme variability in turbidity levels
requires skilled operators and close
operational attention. High turbidity or
excessive color in the source water
could require chemical dosages above
the manufacturer's recommendations for
the particular plant. Excessive turbidity
levels may require presedimentation or
a larger capacity plant. Specific design
criteria of a typical package plant and
operating and maintenance
requirements can vary, but an example
schematic is depicted in Figure IV.3.

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 19070
Federal Register/Vol.  65, No.  69/Monday, April 10, 2000/Proposed Rules
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                  Federal Register/Vol. 65, No.  69/Monday, April 10, 2000/Proposed Rules
                                                                    19071
  The Agency believes that historic data
show that package plants have a
comparable ability to meet turbidity
requirements as conventional or direct
filtration systems.
  A 1987 report of pilot testing using a
trailer-mounted package plant system to
treat raw water from Clear Lake in
Lakeport, California demonstrates the
ability of such systems to achieve low
turbidity requirements. The raw water
contained moderate to high turbidity (18
to 103 NTU). Finished water turbidities
ranged from 0.07 to 0.11 NTU (EPA,
1987). Two previous studies (USEPA,
1980a,b and Cambell et al., 1995) also
illustrate the ability of package systems
throughout the country to meet historic
turbidity performance criteria. These
studies are described briefly:
Package Water Treatment Plant
Performance Evaluation (USEPA,
1980a,b)
  The Agency conducted a study of
package water treatment systems which
encompassed 36 plants in Kentucky,
West Virginia, and Tennessee. Results
from that study showed that the plants
could provide water that met the
existing turbidity limits established
under the National Interim Primary
Drinking Water Standards. Of the 31
plants at which turbidity measurements
were made, 23 (75 percent) were found
to be meeting existing standards. Of the
8 which did not meet requirements, one
did not use chemical coagulants, and 6
operated les's than four hours per day.
(USEPA, 1980a, b)
Package Plants for Small Systems: A
Field Study (Cambell et al, 1995)
  This 1992 project evaluated the
application of package plant technology
to small communities across the U.S.
The project team visited 48 facilities
across the U.S. Of the 29 surface water
and GWUDI systems, 21 (72 percent)
had grab turbidity samples less than 0;5
NTU, the 95 percent limit which
became effective in June of 1993.
Twelve systems (41 percent) had values
less than today's proposed 0.3 NTU 95
percent turbidity limit. (Cambell et al.,
1995) It should be noted that today's
rule requires compliance with turbidity
limits based on 4 hour measurments.
  The Agency recently evaluated Filter
Plant Performance Evaluations (FPPEs)
conducted by the State of Pennsylvania,
in an effort to quantify the comparative
abilities of package plants and
conventional filtration systems to meet
the required turbidity limits. The data
set consisted of 100 FPPEs conducted at
systems serving populations fewer than
10,000 (PADEP, 1999). Thirty-seven
FPPEs were conducted at traditional
conventional filtration systems while 37
were conducted at package plants or
"pre-engineered"  systems. The
remaining 26  systems utilized other
filtration technologies.
  The FPPEs provided a rating of either
acceptable or unacceptable as
determined by the evaluation team. This
rating was based on an assessment of
the capability of individual unit
processes to continuously provide an
effective barrier to the passage of
microorganisms. Specific performance
goals were utilized to evaluate the
performance of the system including the
consistent ability to produce a finished
water turbidity of less than 0.1 NTU,
which is lower than the combined filter
effluent turbidity requirement in today's
proposed rule. Seventy-three percent of
the traditional conventional filtration
systems were rated acceptable and 89
percent of the package plants were rated
acceptable.
  The Agency also evaluated historic
turbidity data graphs contained within
each FPPE to provide a comparison of
the ability of package plants and
conventional  systems to meet the 1 NTU
max and 0.3 NTU 95 percent
requirements that are contained in
today's proposed rule. Sixty-seven
percent of the conventional systems
would meet today's proposed
requirements while 74 percent of
package systems in the data set would
meet today's proposed requirements.
The Agency believes that, when viewed
alongside the aforementioned studies
(USEPA, 1980a,b and Cambell et al.,
1995), it is apparent that package
systems have the ability to achieve more
stringent turbidity limits.

Correlation Between CFE Requirements
and 2-log Cryptosporidium Removal

  Recent pilot scale experiments
performed by the Agency assessed the
ability of conventional treatment to
control Cryptosporidium under steady
state conditions. The work was
performed with a pilot plant that was
designed to minimize flow rates and as
a result the number of oocyst required
for continuous spiking. (Dugan et al.
1999)
  Viable oocysts were fed into the plant
influent at a concentration of 106/L for
36 to 60 hours. The removals of oocysts
and the surrogate parameters turbidity,
total particle counts and aerobic
endospores were measured through
sedimentation and filtration. There was
a positive correlation between the log
removals of oocysts and all surrogate
parameters through the coagulation and
settling process. With proper
coagulation control, the conventional
treatment process achieved the 2 log
total Cryptosporidium removal required
by the IESWTR. In all cases where 2 log
total removal was not achieved, the
plant also did not comply with the
lESWTR's CFE turbidity requirements.
Table IV.6 provides information on
Cryptosporidium removals from this
study.                             ;
                           TABLE IV.6.—LOG REMOVAL OF OOCYSTS (DUGAN ET AL. 1999)
Run
1 	
2 	
3 	 , 	
4
5 	
6 	 	 	
7 	
8 	 , 	
9 	
10 	 	 	
Log removal
crypto
4.5
5.2
1.6
1.7
4.1
5.1
0.2
0.5
5.1
4.8
Exceeds CFE
No.
No.
Yes, average CFE 2.1 NTU.
Yes, only 88% CFE under 0.3 NTU.
No.
No.
Yes, average CFE 0.5 NTU.
Yes, only 83% CFE under 0.3 NTU.
No.
No. :
requirements
*








i

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 19072
Federal  Register/Vol. 65, No. 69/Monday,  April 10, 2000/Proposed  Rules
 iii. Proposed Requirements
   Today's proposed rule establishes
 combined filter effluent turbidity
 requirements which apply to all surface
 water and GWUDI systems which filter
 and serve populations fewer than
 10,000. For conventional and direct
 filtration systems, the turbidity level of
 representative samples of a system's
 combined filter effluent water must be
 less than or equal to 0.3 NTU in at least
 95 percent of the measurements taken
 each month. The turbidity level of
 representative samples of a system's
 filtered water must not exceed 1 NTU at
 anytime.
   For membrane filtration,
 (microfiltration, ultrafiltration,
 nanofiltration, and reverse osmosis) the
 Agency is proposing to require that the
 turbidity level of representative samples
 of a system's combined filter effluent
 water must be less than or equal to 0.3
 NTU in at least 95 percent of the
 measurements taken each month. The
 turbidity level of representative samples
 of a system's filtered water must not
 exceed 1 NTU at any time. EPA
 included turbidity limits for membrane
 systems to allow such systems the
 ability to opt out of a possible costly
 demonstration of the ability to remove
 Cryptosporidium. The studies displayed
 previously in Table IV.4, demonstrate
 the ability of these technologies to
 achieve log-removals in excess of 2 log.
 In lieu of these turbidity limits, a public
 water,system which utilizes membrane
 filtration may demonstrate to the State
 for purposes of membrane approval
 (using pilot plant studies or other
 means) that membrane filtration in
 combination with disinfection treatment
 consistently achieves 3 log removal and/
 or inactivation of Giardia lamblia cysts,
 4 log removal and/or inactivation of
 viruses, and 2 log removal of
 Cryptosporidium oocysts. For each
 approval, the State will set turbidity
 performance requirements that the
 system must meet at least 95 percent of
 the time and that the system may not
 exceed at any time at a level that
 consistently achieves 3 log removal and/
 or inactivation of Giardia lamblia cysts,
 4 log removal and/or inactivation of
 viruses, and 2 log removal of
 Cryptosporidium oocysts.
  Systems utilizing slow sand or
 diatomaceous earth filtration must
 continue to meet the combined filter
effluent limits established for these
technologies under the SWTR (found in
 § 141.73 (b) and (c)). Namely, the
turbidity level of representative samples
of a system's filtered water must be less
than or equal to 1 NTU in at least 95
percent of the measurements taken each
                     month and the turbidity level of
                     representative samples of a system's
                     filtered water must at no time exceed 5
                     NTU.
                       For all other alternative filtration
                     technologies (those other than
                     conventional, direct, slow sand,
                     diatomaceous earth, or membrane),
                     public water systems must demonstrate
                     to the State for purposes of approval
                     (using pilot plant studies or other
                     means), that the alternative filtration
                     technology in combination with
                     disinfection treatment, consistently
                     achieves 3 log removal and/or
                     inactivation of Giardia lamblia cysts, 4
                     log removal and/or inactivation of
                     viruses, and 2 log removal of
                     Cryptosporidium oocysts. For each
                     approval, the State will set turbidity
                     performance requirements that the
                     system must meet at least 95 percent of
                     the time and that the system may not
                     exceed at any time at a level that
                     consistently achieves 3 log removal and/
                     or inactivation of Giardia lamblia cysts,
                     4 log removal and/or inactivation of
                     viruses, and 2 log removal of
                     Cryptosporidium oocysts.
                     iv. Request for Comments
                      EPA solicits comment on the proposal
                     to require systems to meet the proposed
                     combined filter effluent turbidity
                     requirements. Additionally, EPA solicits
                     comment on the following:
                      • The ability of package plants and/
                     or other unique conventional and/or
                     direct systems to meet the combined
                     filter effluent requirements;
                      • Microbial attachment to particulate
                    material or inert substances in water
                    systems may have the effect of
                    providing "shelter" to microbes by
                    reducing their exposure to disinfectants
                     (USEPA, 1999e). While inactivation of
                     Cryptosporidium is not a consideration
                    of this rule, should maximum  combined
                    filter effluent limits for slow sand and
                    diatomaceous earth filtration systems be
                    lowered to 1 or 2 NTU and/or 95th
                    percentile requirements lowered to 0.3
                    NTU to minimize the ability of turbidity
                    particles to "shelter" Cryptosporidium
                    oocysts?
                      • Systems which practice enhanced
                    coagulation may produce higher
                    turbidity effluent because of the process.
                    Should such systems be allowed to
                    apply to the State for alternative
                    exceedance levels similar to the
                    provisions contained in the rule for
                    systems which practice lime softening?
                      • Issues specific to small systems
                    regarding the proposed combined filter
                    effluent requirements;
                      • Establishment of turbidity limits for
                    alternative filtration technologies;
   • Allowance of a demonstration to
 establish site specific limits in lieu of
 generic turbidity limits, including
 components of such demonstration; and
   • The number of small membrane
 systems employed throughout the
 country.         *
   The Agency also requests comment on
 establishment of turbidity limits for
 membrane systems. While integrity of
 membranes provides the clearest
 understanding of the effectiveness of
 membranes, turbidity has been utilized
 as an indicator of performance (and
 corresponding Cryptosporidium log
 removal) for all filtration technologies.
 EPA solicits comment on modifying the
 requirements for membrane filters to
 meet integrity testing, as approved by
 the State and with a frequency approved
 by the State.
 b. Individual Filter Turbidity
 i. Overview and Purpose
   During development of the IESWTR,
 it was recognized that performance of
 individual filters within a plant were of
 paramount importance to producing
 low-turbidity water. Two important
 concepts regarding individual filters
 were discussed. First, it was recognized
 that poor performance (and potential
 pathogen breakthrough) of one filter
 could be masked by optimal
 performance in other filters, with no
 discernable rise in combined filter
 effluent turbidity. Second, it was noted
 that individual filters are susceptible to
 turbidity spikes (of short duration)
 which would not be captured by four-
 hour combined filter effluent
 measurements. To address the
 shortcomings associated with individual
 filters, EPA established individual filter
 monitoring requirements in the
 IESWTR. For the reasons discussed
 below, the Agency believes it
 appropriate and necessary to extend
 individual filter monitoring
 requirements to systems serving
 populations fewer than 10,000 in the
 LT1FBR.
 ii. Data
  EPA believes that the support and
 underlying principles regarding the
 IESWTR individual filter monitoring
 requirements are also applicable for the
 LTlFBR. The Agency has estimated that
 5,897 conventional and direct filtration
 systems will be subject to today's
 proposed individual filter turbidity
requirements. Information regarding this
 estimate is found  in Section IV.A.2.a of
today's proposal. The Agency has
analyzed information regarding
turbidity spikes and filter masking
which are presented next.

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                  Federal Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed Rules
                                                                     19073
Turbidity Spikes

  During a turbidity spike, significant
amounts of particulate matter (including
Cryptosporidium oocysts, if present)
may pass through the filter. Various
factors affect the duration and
amplitude of filter spikes, including
sudden changes to the flow rate through
the filter, treatment of the filter
backwash water, filter-to-waste
capability, and site-specific water
quality conditions. Recent experiments
have suggest that surging has a
significant effect on rapid sand filtration
performance (Glasgow and Wheatley,
1998). An example filter profile
depicting turbidity spikes is shown in
Figure IV.4.
BILLING CODE 6560-50-P

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19074
Federal Register/Vol.  65,  No, 69/Monday, April 10, 2000/Proposed Rules
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                  Federal Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed Rules
                                                                     19075
  Studies considered by both EPA and
the M-DBP Advisory Committee noted
that the greatest potential for a peak in
turbidity (and thus, pathogen
breakthrough) is near the beginning of
the filter run after filter backwash or
start up of operation (Amirtharajah,
1988; Bucklin, et al. 1988; Cleasby,
1990; and Hall and Croll, 1996). This
phenomenon is depicted in Figure IV.4.
Turbidity spikes also may occur for a
variety of other reasons. These include:
  • Outages or maintenance activities at
processes within the treatment train;
  • Coagulant feed pump or equipment
failure;
  • Filters being run at significantly
higher loading rates than approved;
  • Disruption in filter media;
  • Excessive or insufficient coagulant
dosage; and
  • Hydraulic surges due to pump
changes or other filters being brought
on/off-line.
  A recent study was completed which
evaluated particle removal by filtration
throughout the country. While the
emphasis of this study was particle
counting and removal, fifty-two of the
100 plants surveyed were also surveyed .
for turbidity with on-line turbidimeters. :
While all of the plants were able to meet
0.5 NTU 95 percent of the time, it was
noted that there was a significant
occurrence of spikes during the filter
runs. These were determined to be a
major source of raising the 95th
percentile value for most of the filter
runs. (McTigue et al. 1998)
BILLING CODE 6560-50-P

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19076
Federal Register/Vol.  65, No. 69/Monday, April 10, 2000/Proposed Rules
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      Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
                                                               19077
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Federal Register/Vol. 65, No. 69/Monday, April 10,  2000/Proposed Rules
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      Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
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Federal Register/Vol. 65, No.  69/Monday, April 10, 2000/Proposed Rules
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                Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
                                                                                       19081
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BILLING CODE B580-50-C

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19082
Federal Register/Vol. 65, No. 69/Monday,  April 10, 2000/Proposed Rules
Masking of Filter Performance

  Combined Filter Effluent monitoring
can mask poor performance of
individual filters which, may allow
passage of particulates (including
Cryptosporidium oocysts). One poorly
performing filter, can be effectively
                     "masked" by other well operated filters
                     because water from each of the filters is
                     combined before an effluent turbidity
                     measurement is taken. The following
                     example illustrates this phenomenon.
                       The fictitious City of "Smithville"
                     (depicted in Figure IV.6) operates a
                     conventional filtration plant with four
rapid granular niters as shown below.
Filter number 1 has significant problems
because the depth and placement of the
media are contributing to elevated
turbidities. Filters 2, 3, and 4 do not
have these problems and are operating
properly.
BILLING CODE 6560-50-P

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                 Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19083
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BILUNG CODE 6560-50-C

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19084
Federal Register/Vol.  65,  No. 69/Monday,  April 10, 2000/Proposed  Rules
  Turbidity measurements taken at the
clearwell indicate 0.3 NTU. Filter 4
produces water with a turbidity of 0.08
NTU, Filter 3 a turbidity of 0.2 NTU,
Filter 2 a'turbidity of 0.1 NTU, and
Filter 1 a turbidity of 0.9 NTU. Each
filter contributes an equal proportion of
water, but each is operating at different
turbidity levels which contributes to the
combined filter effluent of 0.32 NTU.
([0.08+0.2+0.1+0.91+4  = 0.32 NTU)
  As discussed previously in Section
IV.2.a, the Agency believes that a system
must meet 0.3 NTU 95 percent of the
time an appropriate treatment technique
requirement that assures an increased
level of Cryptosporidium removal.
While the fictitious system described
above would barely meet the required
CFE turbidity, it is entirely possible that
they would not be achieving an overall
2 log removal of Cryptosporidium with
one filter achieving considerably less
than 2-log removal. This issue
highlights the importance of
understanding the performance of
individual filters relative to overall
plant performance.

iii. Proposed Requirements

  Today's proposed rule establishes an
individual filter turbidity requirement
which applies to all surface water and
GWUDI systems using filtration and
which serve populations fewer than
10,000 and utilize direct or
conventional filtration. In developing
this requirement, the Agency evaluated
several alternatives (A, B and C) in an
attempt to reduce the burden faced by
small systems while still providing: (1)
A comparable level of public health
protection as that afforded to systems
serving 10,000 or more people and (2)
an early-warning tool systems can use to
detect and correct problems with filters.

Alternative A

  The first alternative considered by the
Agency was requiring direct and
conventional filtration systems serving
populations fewer than 10,000 to meet
the same requirements as established for
systems serving 10,000 or more people.
This alternative would require that all
conventional and direct filtration
systems must conduct continuous
monitoring of turbidity (one turbidity
measurement every 15 minutes) for each
individual filter. Systems must provide
an exceptions report to the State as part
of the existing combined filter effluent
reporting process for any of the
following circumstances:
  (1) Any individual filter with a
turbidity level greater than 1.0 NTU
based on two consecutive measurements
fifteen minutes apart;
                       (2) Any individual filter with a
                     turbidity greater than 0.5 NTU at the
                     end of the first four hours of filter
                     operation based on two consecutive
                     measurements fifteen minutes apart;
                       (3) Any individual filter with
                     turbidity levels greater than 1.0 NTU
                     based on two consecutive measurements
                     fifteen minutes apart at any time in each
                     of three consecutive months (the system
                     must, in addition to filing an exceptions
                     report, conduct a self-assessment of the
                     filter); and
                       (4) Any individual filter with
                     turbidity levels greater than 2.0 NTU
                     based on two consecutive measurements
                     fifteen minutes apart at any time in each
                     of two consecutive months (the system
                     must file an exceptions report and must
                     arrange for a comprehensive
                     performance evaluation (CPE) to be
                     conducted by the State or a third party
                     approved by the State).
                       Under the first two circumstances
                     identified, a system must produce a
                     filter profile if no obvious reason for the
                     abnormal filter performance can be
                     identified.

                     Alternative B
                       The second alternative considered by
                     the Agency represents a slight
                     modification from the individual filter
                     monitoring requirements of large
                     systems. The 0.5 NTU exceptions report
                     trigger would be omitted in an effort to
                     reduce the burden associated with daily
                     data evaluation. Additionally, the filter
                     profile requirement would be removed.
                     Requirement language was slightly
                     modified in an effort to simplify the
                     requirement for small system operators.
                     This alternative would still require that
                     all conventional and direct nitration
                     systems conduct continuous monitoring
                     (one turbidity measurement every 15
                     minutes) for each individual filter, but
                     includes the following three
                     requirements:
                       (1) A system must provide an
                     exceptions report to the State as part of
                     the existing combined effluent reporting
                     process if any individual filter turbidity
                     measurement exceeds 1.0 NTU (unless
                     the system can show that the next
                     reading is less than 1.0 NTU);
                       (2) If a system is required to submit
                     an exceptions report for the same filter
                     in three consecutive months, the system
                     must conduct a self-assessment of the
                     filter.
                       (3) If a system is required to submit
                     an exceptions report for the same filter
                     in two consecutive months which
                     contains an exceedance of 2.0 NTU by
                     the same filter, the system must arrange
                     for a CPE to be conducted by the State
                     or a third party approved by the State.
Alternative C
  The third alternative considered by
the Agency would include new triggers
for reporting and follow-up action in an
effort to reduce the daily burden
associated with data review. This
alternative would still require that all
conventional and direct filtration
systems must conduct continuous
monitoring (one turbidity measurement
every 15 minutes) for each individual
filter, but would include the following
three requirements:
  (1) A system must provide an
exceptions report to the State as part of
the existing combined effluent reporting
process if filter samples exceed 0.5 NTU
in at least 5 percent of the
measurements taken each month and/or
any individual filter measurement
exceeds 2.0 NTU (unless the system can
show that the following reading was  <
2.0 NTU).
  (2) If a system is required to submit
an exceptions report for the same filter
in three consecutive months the system
must conduct a self-assessment of the
filter.
  (3) If a system is required to submit
an exceptions report for the same filter
in two consecutive months which
contains an exceedance of 2.0 NTU by
the same filter, the system must arrange
for a CPE to be conducted by the State
or a third party approved by the State.
  For all three alternatives the
requirements regarding self assessments
and CPEs are the same. If a CPE is
required, the system must arrange for
the State or a third party approved by
the State to conduct the CPE no later
than 30 days following the exceedance.
The CPE must be completed and
submitted to the State no later than 90
days following the exceedance which
triggered the CPE. If a self-assessment is
required it must take place within 14
days of the exceedance and the system
must report to the State that the self-
assessment was conducted. The self
assessment must consist of at least the
following components:
  • assessment of filter performance;
  • development of a filter profile;
  • identification and prioritization of
factors limiting filter performance;
  • assessment of the applicability of
corrections; and
  • preparation of a filter self
assessment report.
  In considering each of the above
alternatives, the Agency attempted to
reduce the burden faced by small
systems. Each of the three alternatives
was judged to provide levels of public
health protection comparable to those in
the IESWTR for large systems.
Alternative A, because it contains the

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                  Federal Register/Vol.  65, No. 69/Monday, April 10, 2000/Proposed Rules
                                                                     19085
same requirements as EESWTR, was
expected to afford the same level of
public health protection. Alternative B,
(which removes the four-hour 0.5 MTU
trigger and the filter profile
requirement) was expected to afford
comparable health protection because
the core components which provide the
overwhelming majority of the public
health protection (monitoring
frequency, trigger which requires
follow-up action, and the follow-up
actions) are the same as the IESWTR.
Alternative C was expected to provide
comparable health protection because
follow-up action is the same as under
the IESWTR and a 0.5 NTU 95percent
percentile trigger was expected to
identify the same systems which the
triggers established under the IESWTR
would identify. All three were also
considered useful diagnostic tools for
small systems to evaluate the
performance of filters and correct
problems before follow-up action was
necessary. The first alternative was
viewed as significantly more
challenging to implement and
burdensome for smaller systems due to
the amount of required daily data
review. This evaluation was also echoed
by small entity representatives during
the Agency's SBREFA process as well as
stakeholders at each of the public
meetings held to discuss issues related
to today's proposed rule. While
Alternative C reduced burden associated
with daily data review, it would
institute a very different trigger for small
systems than established by the EESWTR
for large systems. This was viewed as
problematic by several stakeholders
who stressed the importance of
maintaining similar requirements in
order to limit transactional costs and
additional State burden. Therefore, the
Agency is proposing Alternative B as
described above, which allows operators
to expend less time to evaluate their
turbidity data. Alternative B maintains a
comparable level of public health
protection as those afforded large
systems, reduces much of the burden
associated with daily data collection
and review (removing the requirement
to conduct a filter profile allows systems
to review data once a week instead of
daily if they so choose), yet still serves
as a self-diagnostic tool for operators
and provides the mechanism for State
follow-up when significant performance
problems exist.
iv. Request for Comments
  The individual filter monitoring
provisions represent a challenging
opportunity to provide systems with a
useful tool for assessing filters and
correcting problems before State
intervention is necessary or combined
filter turbidity is affected and treatment
technique violations occur. The Agency
is actively seeking comment on this
provision. Because of the complexity of
this provision, specific requests for
comment have been broken down into
five distinct areas.

Comments on the Alternatives
  EPA requests comment on today's
proposed individual filter requirement
and each of the alternatives as well as
additional alternatives for this provision
such as establishing a different
frequency for individual filter
monitoring (e.g., 60 minute or 30 minute
increments). The Agency also seeks
comment or information on:
  • Tools and or guidance which would
be useful and necessary in order to
educate operators on how to comply
with individual filter provisions and
perform any necessary calculations;
  • Data correlating individual filter
performance relative to combined filter
effluent;
  • Contributing factors to turbidity
spikes associated with reduced filter
performance;
  • Practices which contribute to poor
individual filter performance and filter
spikes; and
  • Any additional concerns with
individual filter performance.

Modifications to the Alternatives
  The Agency also seeks comment on a
variety of proposed modifications to the
individual filter monitoring alternatives
discussed which could be incorporated
in order to better address the concerns
and realities of small surface water
systems. These modifications include:
  • Modification of the alternatives to
include a provision which would
require systems which do not staff the
plant during all hours of operation, to
utilize an alarm/phone system to alert
off-site operators of significantly
elevated turbidity levels  and poor
individual filter performance;
  • A modification to allow
conventional and direct filtration
systems with either 2—3 or less filters to
sample combined filter effluent      -.
continuously (every 15 minutes) in lieu
of monitoring individual filter turbidity.
This modification would reduce the
data collection/analysis burden for the
smallest systems while not
compromising the level of public health
protection;                        •:
  • A modification to lengthen the
period of time  (120 days or a period of
time established by the State but not to
exceed 120 days) for completion of the
CPE and/or a modification to lengthen
the requirement that a CPE must be
conducted no later than 60 or 90 days
following the exceedance; and
  • A modification to require systems
to notify the State within 24 hours of
triggering the CPE or IFA. This would
inform States sooner so they can begin
to work with systems to address
performance of filters and conduct CPEs
and IF As as necessary.

Establishment of Subcategories
  The Agency is also evaluating the
need to establish subcategories in the
final rule for individual filter
monitoring/reporting.  EPA is currently
considering these three categories:
  1. Systems serving populations of
3,300 or more persons;
  2. Systems with more than 2 filters,
but less than 3,300 persons; and
  3. Systems with 2 or fewer filters
serving populations fewer than 3,300
persons.                            ;
  Individual filter monitoring
requirements would also be based on
these subcategories. Systems serving
3,300 or greater would be required to
meet the same individual turbidity
requirements as the IESWTR
(Alternative A as described above).
Systems serving fewer than 3,300 but
using more than 2 filters would be
required to meet a modified version of
the IESWTR individual filter
requirements (Alternative B as
described above). Systems serving fewer
than 3,300 and using 2 or fewer filters
would continue to monitor and report
only combined filter effluent turbidity at
an increased frequency (once every 15
minutes, 30 minutes, or one hour).
  Input and or comment on cut-offs for
subcategories and how to apply
subcategories to Alternatives is
requested. The Agency would also like
to take comment on additional strategies
to tailor individual filter monitoring for
the smallest systems while continuing
to maintain an adequate level of public
health protection. Such possible
strategies include:
  • Since small systems are often
understaffed one approach would
require those systems utilizing only two
or fewer filters to utilize, maintain, and
continually operate an alarm/phone
system during all hours of operation,
which alert off-site operators of
significantly elevated turbidity levels
and poor individual filter performance
and/or automatically shuts the system
down if turbidity levels exceed a
specified performance level. This
modification would be in addition to
the proposed requirements.
  • Establishing a more general
modification which would require
systems which do not staff the plant
during all hours of operation to utilize

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Federal  Register/Vol. 65, No. 69/Monday,  April 10, 2000/Proposed  Rules
an alarm/phone system to alert off-site
operators of significantly elevated
turbidity levels and poor individual
filter performance, and/or to
automatically shut the system down if
turbidity levels exceed a specified
performance level.
  • If systems with 2 or fewer filters is
allowed to sample combined filter
effluent in lieu of individual filter
effluent with a frequency of a reading
every hour and combined filter effluent
turbidity exceeds 0.5 NTU, should the
system be required to take grab samples
of individual filter turbidity for all
filters every 15 minutes until the results
of those samples are lower than 0.5
NTU?
Reliability
  Maintaining reliable performance at
systems using filtration requires that the
filters be examined at intervals to
determine if problems are developing.
This can mean that a filter must go off-
line for replacement or upgrades of
media, underdrains, backwash lines etc.
In order to provide adequate public
health protection at small systems, the
lack of duplicate units can be a problem.
EPA is considering requiring any system
with only one filter to install an
additional filter. The schedule would be
set by the primacy agency, but the filter
would have to be installed no later than
6 years after promulgation. EPA is
requesting comment on this potential
requirement.
Data Gathering Recordkeeping and
Reporting
  The Agency is evaluating data
gathering/reporting requirements for
systems. A system collecting data at a
frequency of once every 15 minutes,
(and operating) 24 hours a day, would
record approximately 2800 data points
for each filter throughout the course of
the month. Although the smallest
systems in operation today routinely
operate on the average of 4 to 12 hours
a day (resulting in 480 to 1400 data
points per filter), these systems  do not
typically use sophisticated data
recording systems such as SCADAs. The
lack of modern equipment at small
systems may result in difficulty with
retrieving and analyzing data for
reporting purposes. While the Agency
intends to issue guidance targeted at
aiding these systems with the data
gathering requirements, EPA is also
seeking feedback on a modification to
the frequency of data gathering required
under each of the aforementioned
options. Specifically, the Agency would
like to request comment on modifying
the frequency for systems serving fewer
than 3,300 to continuous monitoring on
                     a 30 or 60 minute basis. EPA also
                     requests comment on the availability
                     and practicality of data systems that
                     would allow small systems, State
                     inspectors, and technical assistance
                     providers to use individual filter
                     turbidity data to improve performance,
                     perform filter analysis, conduct
                     individual filter self assessments, etc.
                     The Agency is interested in specific
                     practical combinations of data
                     recorders, charts, hand written
                     recordings from turbidimeters, that
                     would accomplish this.

                     Failure of Continuous Turbidity
                     Monitoring
                       Under today's proposed rule, the
                     Agency requires that if there is a failure
                     in the continuous turbidity monitoring
                     equipment, the system must conduct
                     grab sampling every four hours in lieu
                     of continuous monitoring until the
                     turbidimeter is back on-line. A system
                     has five working days to resume
                     continuous monitoring before a
                     violation is incurred. EPA would like to
                     solicit comment on modifying this
                     component to require systems to take
                     grab samples at an increased frequency,
                     specifically every 30 minutes, 1 hour, or
                     2 hours.

                     B. Disinfection Benchmarking
                     Requirements
                       Small systems will be required to
                     comply with the Stage 1 Disinfection
                     Byproduct Rule (Stage 1 DBPR) in the
                     first calendar quarter of 2004.  The Stage
                     1 DBPR set Maximum Contaminant
                     Levels (MCLs) for Total
                     Trihalomethanes (chloroform,
                     bromodichloromethane,
                     chlorodibromomethane, and
                     bromoform), and five Haloacetic Acids
                     (i.e., the sum of the concentrations of
                     mono-, di-, and trichloroacetic acids and
                     mono- and dibromoacetic acids.) The
                     LTlFBR follows the principles set forth
                     in earlier FACA negotiations,  i.e., that
                     existing microbial protection must not
                     be significantly reduced or undercut as
                     a result of systems taking the necessary
                     steps  to comply with the MCL's for
                     TTHM and HAAS set forth in Stage 1
                     DBPR. The disinfection benchmarking
                     requirements are designed to ensure that
                     risk from one contaminant is not
                     increased while risk from another
                     contaminant is decreased.
                       The Stage 1 DBPR was promulgated
                     because disinfectants such as chlorine
                     can react with natural organic and
                     inorganic matter in source water and
                     distribution systems to form
                     disinfection byproducts (DBFs). Results
                     from toxicology studies have shown
                     several DBFs (e.g.,
                     bromodichloromethane, bromoform,
chloroform, dichloroacetic acid, and
bromate) to potentially cause cancer in
laboratory animals. Other DBFs (e.g.,
certain haloacetic acids) have been
shown to cause adverse reproductive or
developmental effects in laboratory
animals. Concern about these health
effects may cause public water utilities
to consider altering their disinfection
practices to minimize health risks to
consumers.
  A fundamental principle, therefore, of
the 1992-1993 regulatory negotiation
reflected in the 1994 proposal for the
IESWTR was that new standards for
control of DBFs must not result in
significant increases in microbial risk.
This principle was also one of the
underlying premises of the 1997 M-DBP
Advisory Committee's deliberations,
i.e., that existing microbial protection
must not be significantly reduced or
undercut as a result of systems taking
the necessary steps to comply with the
MCL's for TTHM and HAAS set forth in
Stage 1 DBPR. The Advisory Committee
reached agreement on the use of
microbial profiling and benchmarking
as a process by which a PWS and the
State, working together, could assure
that there would be no significant
reduction in microbial protection as the
result of modifying disinfection
practices in order to comply with Stage
1 DBPR.
  The process established under the
IESWTR has three components: (1)
Applicability Monitoring; (2)
Disinfection Profiling; and (3)
Disinfection Benchmarking. These
components have the following three
goals respectively: (1) determine which
systems have annual average TTHM and
HAAS levels close enough to the MCL
(e.g., 80 percent of the MCL) that they
may need to consider altering their
disinfection practices to comply with
Stage 1 DBPR; (2) those systems that
have TTHM and HAA5 levels of at least
80 percent of the MCLs must develop a
baseline of current microbial
inactivation over the period of 1 year;
and (3) determine the benchmark, or the
month with the lowest average level of
microbial inactivation, which becomes
the critical period for that year.
   The aforementioned components were
applied to systems serving 10,000 or
more people in the IESWTR and were
carried out sequentially. In response to
concerns about early implementation
(any requirement which would require
action prior to 2 years after the
promulgation date of the rule), the
Agency is considering modifying the
IESWTR approach for small systems, as
described in the following section.
Additionally, the specific provisions
have been modified to take into account

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                   Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
                                                                     19087
 specific needs of small systems. EPA's
 goal in developing these requirements is
 to recognize the specific needs of small
 system and States, while providing
 small systems with a useful means of
 ensuring that existing microbial
 protection must not be significantly
 reduced or undercut as a result of
 systems taking the necessary steps to
 comply with the MCL's for TTHM and
 HAAS set forth in Stage 1 DBPR.
   The description of the disinfection
 benchmarking components of today's
 proposed rule will be broken into the
 three segments: (1) Applicability
 Monitoring; (2) Disinfection Profiling;
 and (3) Disinfection Benchmarking.
 Each section will provide an overview
 and purpose, data, a description of the
 proposed requirements, and request for
 comment.
 1. Applicability Monitoring
 a. Overview and Purpose
   The purpose of the TTHM and HAAS
 applicability monitoring is to serve as
 an indicator for systems that are likely
 to consider making changes to tiieir
 disinfection practices in order to
 comply with the Stage 1 DBPR. TTHM
 samples which equal or exceed 0.064
 mg/L and/or HAAS samples equal or
 exceed 0.048 mg/L (80 percent of their
 respective MCLs) represent DBF levels
 of concern. Systems with TTHM or
 HAAS levels exceeding 80 percent of
 the respective MCLs may consider
 changing their disinfection practice in
 order to comply with the Stage 1 DBPR.

 b. Data

   In 1987, EPA established monitoring
 requirements for 51 unregulated
 synthetic organic chemicals.
 Subsequently, an additional 113
 unregulated contaminants were added
 to the monitoring requirements.
 Information on TTHMs has become
 available from the first round of
 monitoring conducted by systems
 serving fewer than 10,000 people.
  Preliminary analysis of the data  from
 the Unregulated Contaminant
 Information System (URCIS, Data)
 suggest that roughly 12 percent of
 systems serving fewer than 10,000
 would exceed 64 |i/L or 80 percent of
 the MCL for TTHM (Table IV.7). This
 number is presented only as an
 indicator, as it represents samples  taken
 at the entrance to distribution systems.
 In general, TTHMs and HAASs tend to
 increase with time as water travels
 through the distribution system. The
 Stage 1 Disinfection Byproducts Rule •
 estimated 20 percent of systems serving
 fewer than 10,000 would exceed 80
 percent of the MCLs for either TTHMs
 or HAASs or both. EPA is working to
 improve the knowledge of TTHM and
 HAAS formation kinetics in the
 distribution systems for systems serving
 fewer than 10,000 people. EPA is
 currently developing a model to predict
 the formation of TTHM and HAAS in
 the distribution system based on
 operational measurements. This model
 is not yet available. In order to develop
 a better estimate of the percent of small
 systems that would be triggered into the
 profiling requirements (i.e., develop a
 profile of microbial inactivation over a
 period of 1 year) EPA is considering the
 following method:
   •  Use URCIS data to show how many
 systems serving 10,000 or more people
 have TTHM levels at or above 0.064 mg/
 L;
   •  Compare those values to the data
 received from the Information
 Collection Rule for TTHM average
 values taken at representative points in
 the distribution system;
   •  Determine the mathematical factor
 by which the two values differ; and
   •  Apply that factor to the URCIS data
 for systems serving fewer than 10,000
 people to estimate the percent of those
 systems that would have TTHM values ,
 at or above 0.064mg/L as an average of
 values taken at representative points in
 the distribution system.
                             TABLE IV.7.—TTHM LEVELS AT SMALL SURFACE SYSTEMS
                                  [Data from Unregulated Contaminant Database, 1987-921]
System size (population served)
<500 	
501-1,000 	
1,001-3.300 	
3,301-10,000 	

Total 	
Total num-
ber of sys-
tems
74
44
114
116

348
Number of
systems w/
ave. TTHM
> 64 ug/L
(80 % of
MCL)
n in0/*}
6 (136%)
12 (10 5%)
OC /O-l f!0/\

43 (12.4%)
!
Maximum
level of ave.
TTHM
(US/L) :
cc
999
179
97Q

279
  1ln Unregulated Contaminant Database (1987-1992), there are ten States (i.e., CA, DE, IN, MD, Ml, MO, NC, NY, PR, WV). However only
eight of them can be identified with the data of both population and TTHM for systems serving fewer than 10,000 people (See next page).
  The Agency requests comment on this
approach to estimating TTHM levels in
the distribution system based on TTHM
levels at the entry point to the
distribution system. The Agency also
requests comment on the relationship of
HAAS formation relative to TTHM
formation in the distribution system.
Specifically, is there data to support the
hypothesis that HAASs do not peak at
the same point in the distribution
system as TTHMs?
  The Agency also received two full
years of TTHM data for seventy-four
systems in the State of Missouri
(Missouri, 1998). This data consisted of
quarterly TTHM data, which was
converted into an annual average. The
data (presented in Table IV.8)
demonstrates a very different picture
than that displayed by the URCIS data
described above. In 1996, 88 percent of
the systems exceeded 64 ug/L, while in
1997, 85 percent exceeded 64 Ug/L.
Figure IV.7 graphically displays this
data set.

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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
               TABLE IV.8—TTHM LEVELS AT SMALL SURFACE SYSTEMS IN THE STATE OF MISSOURI
                                         [State of Missouri, 1996, 1997]
1
Year

1996 	
1997
All years 	


Total num-
ber of sys-
tems

74
75
149

Number of
systems w/
ave. TTHM
> 64 ug/L
(80 percent
of MCL)
65 (88%)
64 (85%)
129 (87%)


Maximum
Level of
Ave. TTHM
(ug/L)

276
251
276

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                      a
                     s
                                                                                         
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Federal  Register/Vol. 65, No.  69/Monday, April  10,  2000/Proposed Rules
shown in Table IV. 8 is similar to the
methodology required under the Stage 1
DBPR.
c. Proposed Requirements
  EPA considered four alternatives for
systems to use TTHM and HAAS data to
determine which systems whether they
would be required to develop a
disinfection profile. In today's proposed
rule, EPA is proposing Alternative 4.

Alternative 1
  The IESWTR required that systems
monitor for TTHMs at four points in the
distribution system each quarter. At
least one of those samples must be taken
at a point which represents the
maximum residence time of the water in
the system. The remaining three must be
taken at representative locations in the
distribution system, taking into account
number of persons  served, different
sources of water and different treatment
methods employed. The results of all
analyses per quarter are averaged and
reported to the State.
  EPA considered applying this
alternative to systems serving fewer
than 10,000 people and requested input
from small system operators and other
interested parties, including the public.
Based on the feedback EPA received,
two other alternatives were developed
for consideration (listed as Alternatives
2 and 3).

Alternative 2
  EPA considered requiring systems
serving fewer than  10,000 people to
monitor for TTHM  and HAAS at the
point of maximum  residence time
according to the following schedule:
  • No less than once per quarter per
treatment plant operated for systems
serving populations between 500 and
10,000 persons; and no less than once
per year per treatment plant during the
month of warmest water temperature for
systems serving populations less than
500. If systems wish to take additional
samples, however, they would be
permitted to do so.
  • Systems may consult with States
and elect not to perform TTHM and
HAAS monitoring and proceed directly
with the development of a disinfection
profile.
  This alternative provides an
applicability monitoring frequency
identical to the DBF monitoring
frequency under the Stage 1 DBPR that
systems will have to comply with in
2004. In addition, it allows systems the
flexibility to skip TTHM and HAAS
monitoring completely, pending State
approval, and begin profiling
immediately.
                    Alternative 3
                      EPA considered requiring all systems
                    serving fewer than 10,000 people to
                    monitor once per year per system during
                    the month of warmest water
                    temperature of 2002 and at the point of
                    maximum residence time.
                      During the SBREFA process and
                    during stakeholder meetings, EPA
                    received some positive comments
                    regarding Alternative 3 as the least
                    burdensome approach. Other
                    stakeholders, however, pointed out that
                    Alternative 3 does not allow systems to
                    measure seasonal variation as is done in
                    Alternative 2 for systems serving
                    populations between 500 and 10,000.
                    Several stakeholders agreed that despite
                    the costs,  the information obtained from
                    applicability monitoring will be useful.
                    EPA agrees that it is valuable to systems
                    to monitor and understand the seasonal
                    variation in TTHM and HAAS values,
                    however, EPA has determined that
                    requiring a" full year of monitoring may
                    place an excessive burden on both
                    States and systems. In order to complete
                    a full year of monitoring and another
                    full year of disinfection data gathering,
                    systems would have to start TTHM and
                    HAAS monitoring January of 2002.
                      Under SDWA, States have two years
                    to develop their own regulations as part
                    of their primacy requirements, EPA
                    recognized that requiring Applicability
                    Monitoring during this period would
                    pose a burden on States. In response to
                    these concerns, the Agency developed a
                    new alternative, described in the
                    following paragraph.
                    Alternative 4
                      Applicability Monitoring is optional
                    and not a requirement under today's
                    proposed  rule. If a system has TTHM
                    and HAAS data taken during the month
                    of warmest water temperature (from
                    1998-2002) and taken at the point of
                    maximum residence time, they may
                    submit this data to the State prior to
                    [DATE 2 YEARS AFTER PUBLICATION
                    OF FINAL RULE]. If the data shows
                    TTHM and HAAS levels less than 80
                    percent of the MCLs, the system does
                    not have to develop a disinfection
                    profile. If the data shows TTHM and
                    HAAS levels at or above 80 percent of
                    the MCLs, the system would be required
                    to develop a disinfection profile in 2003
                    as described later in section IV.B.2. If
                    the system does not have, or does not
                    gather TTHM and HAAS data during the
                    month of warmest water temperature
                    and at the point of maximum residence
                    tune in the distribution system as
                    described, then the system would
                    automatically be required to develop a
                    disinfection profile starting January 1  of
2003. This option still provides systems
with the necessary tools for assessing
potential changes to their disinfection
practice, (i.e. the generation of the
profile), while not forcing States to pass
their primacy regulations, contact all
small systems within their jurisdiction,
and set up TTHM and HAAS monitoring
all within the first year after
promulgation of this rule. Systems will
still be able to ensure public health
protection by having the disinfection
profile when monitoring under Stage 1
DBPR takes effect. It should be noted
that EPA estimates the cost for
applicability monitoring (as described
in Alternative 4) and disinfection
profiling (as described in Alternative 3
in Section IV.B.2.C of this preamble) are
roughly equivalent. EPA anticipates that
systems with known low levels of TOC
may opt to conduct the applicability
monitoring while the remaining systems
will develop a disinfection profile.
d. Request for Comment
  EPA requests comment on the
proposed requirement, other
alternatives listed, or other alternatives
that have not yet been raised for
consideration. The Agency also requests
comment on approaches for determining
the percent of systems that would be
affected by this requirement.
Specifically:
  • With respect to Alternative 4, the
Agency requests comment on
approaches for determining the percent
of systems that might demonstrate
TTHM and HAAS levels less than 80
percent of their respective MCLs and
would therefore not develop a
disinfection profile.
  • The Agency requests additional
information (similar to the State of
Missouri data discussed previously) on
the current levels of TTHM and HAASs
in the distribution systems of systems
serving fewer than 10,000 people.
  • The Agency requests comment on
developing a TTHM and HAAS
monitoring scheme during die winter
months as opposed to the current
monitoring scheme based on the highest
TTHM/HAA5 formation potential
during the month of warmest water
temperature. If a relationship can be
established, and shown to be consistent
through geographical variations, EPA
would consider modifying an
alternative so that applicability
monitoring would occur during the 1st
quarter of 2003.
  • The Agency requests comment on
modifying Alternative 3, to require
systems to begin monitor for TTHMs
and HAASs during the warmest water
temperature month of 2003. The results
of this monitoring would be used to

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                  Federal Register/Vol.  65,  No. 69/Monday, April 10, '2000/Proposed Rules
                                                                     19091
determine whether a system would need
to develop a disinfection profile during
2004. This option is closer in structure
and timing to the IESWTR and has been
included for comment. It should be
noted, however, that postponing the
disinfection profile until 2004 would
prevent systems from having
inactivation data prior to their
compliance date with  the Stage 1 DBPR,
possibly compromising simultaneous
compliance.
2. Disinfection Profiling
a. Overview and Purpose

  The disinfection profile is a graphical
representation showing how
disinfection varies at a given plant over
time. The profile gives the plant
operator an idea of how seasonal
changes in water quality and water
demand can have a direct effect on the
level of disinfection the plant is
achieving.
  The strategy of disinfection profiling
and benchmarking stemmed from data
provided to the EPA and M-DBP
Advisory Committee by PWSs and
reviewed by stakeholders. The microbial
inactivation data (expressed as logs of
Giardia lamblia inactivation) used by
the M—DBP Advisory Committee
demonstrated high variability.
Inactivation varied by several log on a
day-to-day basis at any particular
treatment plant and by as much as tens
of logs over a year due to changes in
water temperature, flow rate (and,
consequently, contact time), seasonal
changes in residual disinfectant, pH,
and disinfectant demand and,
consequently, disinfectant residual.
There were also differences between
years at individual plants. To address
these variations, M-DBP stakeholders
developed the procedure of profiling
inactivation levels at an individual
plant over a period of at least one year,
and then establishing a benchmark of
minimum inactivation as a way to
characterize disinfection practice. This,
approach makes it possible for a plant
that may need to change its disinfection
practice in order to meet DBP MCLs to :
determine the impact the change would
have on its current level of disinfection
or inactivation and, thereby, to assure
that there is no  significant increase in
microbial risk. In order to develop the
profile, a system must measure four
parameters (EPA is assuming most small
systems use chlorine as their         '•
disinfection agent, and these
requirements are based on this
assumption):
  (1) Disinfectant residual concentration
(C, in mg/L) before or at the first
customer and just prior to each
additional point of disinfectant
addition;
  (2) Contact time (T, in minutes)
during peak flow conditions;
  (3) Water temperature (°C); and
  (4) pH.
  Systems convert this operational data
to a number representing log
inactivation values for Giardia by using
tables provided by EPA. Systems graph
this information over time to develop a
profile of their microbial inactivation.
EPA will prepare guidance specifically
developed for small systems to assist in
the development of the disinfection
profile. Several spreadsheets and simple
programs are currently available to aid
in calculating microbial inactivation
and the Agency intends to make such
spreadsheets available in guidance.

b. Data

  Figure IV.8a depicts a hypothetical
disinfection profile showing seasonal
variation in microbial inactivation.
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19092
Federal Register/Vol. 65, No. 69/Monday, April 10,  2000/Proposed Rules
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                  Federal Register/Vol.  65, No. 69/Monday, April 10,  2000/Proposed Rules
                                                                     19093
c. Proposed Requirements
  EPA considered four alternatives for
requiring systems to develop the
disinfection profile.
Alternative 1
  The IESWTR requires systems serving
10,000 or more persons to measure the
four parameters described above and
develop a profile of microbial
inactivation on a daily basis. EPA
considered extending this requirement
to systems serving fewer than 10,000
persons and requested input from small
system operators and other interested
stakeholders including the public. EPA
received feedback that this requirement
would place too heavy of a burden on
the small system operator for at least
two reasons:
  • Small system operators are not
present at the plant every day; and
  • Small systems often have only one
operator at a plant who is responsible
for all aspects of maintenance,
monitoring and operation.
Alternative 2
  EPA also considered not requiring the
disinfection profile at all. After
consideration of the feedback of small
system operators and other interested
stakeholders, however, EPA believes
that there is a strong benefit in  the plant
operator knowing the level of microbial
inactivation, and that the principles
developed during the regulation
negotiation and Federal Advisory
Committee prior to promulgation of the
lESVVTR could be applied to small
systems for the purpose of public health
protection. Recognizing the potential
burdens the profiling procedures placed
on small systems, EPA considered two
additional alternatives.
Alternative 3
  EPA considered requiring all systems
serving fewer than 10,000 persons, to
develop a disinfection profile based on
weekly measurements for one year
during or prior to 2003. A system with
TTHM and HAAS levels less than 80
percent of the MCLs (ba.sed on either
required or optional monitoring as
described in section IV.B.l) would not
be required to conduct disinfection
profiling. EPA believes this alternative
would save the operator time (in
comparison to Alternative 1), and still
provide information on seasonal
variation over the period of one year.

Alternative 4
  Finally, EPA considered a monitoring
requirement only during a one month
critical monitoring period to be
determined by the State. In general,
colder temperatures reduce disinfection
efficiency. For systems in warmer       :
climates, or climates that do not change
very much during the course of the year,
the State would identify other critical
periods or conditions. This alternative
reduces the number of times the
operator has to calculate the microbial  ;
inactivation.
  EPA considered all of the above
alternatives, and in today's proposed
rule, EPA is proposing Alternative 3.
First, this  alternative does not require
systems to begin monitoring before
States have two years to develop their
regulations as part of primacy
requirements. Given early
implementation concerns, the timing of
this alternative appears to be the most
appropriate in balancing early
implementation issues with the need for
systems to prepare for implementation  ,
of the Stage 1 DBPR and ensuring
adequate and effective microbial
protection. Second, it allows systems
and States which have been proactive in
conducting applicability monitoring to
reduce costs for those systems which
can demonstrate low TTHM and HAAS
levels. Third, this alternative allows
systems and States the opportunity to
understand seasonal variability in
microbial  disinfection. Finally, this
alternative takes into account the
flexibility needed by the smallest
systems while maintaining comparable
levels of public health protection with
the larger systems.
Request for Comments
  EPA requests comment on this
proposed requirement as well as
Alternatives 1,2, and 4. The Agency also
requests comment on a possible
modification to Alternatives 1, 3 and 4.  '
Under this modification, systems
serving populations fewer than 500
would have the opportunity to apply to
the State to perform the weekly
inactivation calculation (although data
weekly data collection would still be
required). If the system decided to make
a change in disinfection practice, then
the State would assist the system with
the development of the disinfection
profile.
  The Agency also requests comment on
a modification to Alternative 3 which
would require systems to develop a
disinfection profile in 2004 only if
Applicability Monitoring conducted in
2003 indicated TTHM and HAAS levels
of 80 percent or greater of the MCL. This
modification would be coupled with the
applicability monitoring modification
discussed in the previous section.

3. Disinfection Benchmarking
a. Overview and Purpose

  The DBPR requires systems to meet
lower MCLs for a number of disinfection
byproducts. In order to meet these
requirements, many systems will
require changes to their current
disinfection practices. In order to ensure
that current microbial inactivation does
not fall below those levels required for
adequate Giardia and virus inactivation
as required by the SWTR, a disinfection
benchmark is necessary.  A disinfection
benchmark represents the lowest
average monthly Giardia inactivation
level achieved by a system. Using this
benchmark States and systems can begin
to understand die current inactivation
achieved at the system, and estimate
how changes to disinfection practices
will affect inactivation.

b. Data

  Based on the hypothetical
disinfection profile depicted in Figure
IV.8a, the benchmark, or critical period,
is the lowest level of inactivation
achieved by the system over the course
of the year. Figure IV.8b shows that this
benchmark (denoted by the dotted line)
takes place in December for the
hypothetical system.
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                                                                    19095
c. Proposed Requirements

  If a system that is required to produce
a disinfection profile decides to make a
significant change in disinfection
practice after the profile is developed, it
must consult with the State and receive
approval before implementing such a
change. Significant changes in
disinfection practice are defined as: (1)
moving the point of disinfection (other
than routine seasonal changes already
approved by the State); (2) changing the
type of disinfectant; (3) changing the
disinfection process; or (4) making other
modifications designated as significant
by the State. Supporting materials for
such consultation with the State must
include a description of the proposed
change, the disinfection profile
developed under today's proposed rule
for Giardia lamblia (and, if necessary,
viruses for systems using ozone or
chlorarnines), and an analysis of how
the proposed change might affect the
current level of Giardia inactivation.  In
addition, the State is required to review
disinfection profiles as part of its
periodic sanitary survey.
  A log inactivation benchmark is
calculated as follows:
  (I) Calculate the average log
inactivation for either each calendar
month, or critical monitoring period
(depending on final rule requirement for
the profiling provisions).
  (2) Determine the calendar month
with the  lowest average log inactivation;
or lowest inactivation level within the
critical monitoring period.
  (3) The lowest average month, or
lowest level during the critical
monitoring period becomes the critical
measurement for that year.
  (4) If acceptable data from multiple
years are available, the average of
critical periods for each year becomes
the benchmark.
  (5) If only one year of data is
available, the critical period (lowest
monthly average inactivation level) for
that year is the benchmark.
d. Request for Comments

  EPA has included a requirement that
State approval be obtained prior to
making a significant change to
disinfection practice. EPA requests
comment on whether the rule should
require State approval or whether only
state consultation is necessary.
  EPA also requests comment on
providing systems serving fewer than
500 the option to provide raw data to
the State, and allowing the State to
determine the benchmark.
C. Additional Requirements

1. Inclusion of Cryptosporidium in
definition of GWUDI
a. Overview and Purpose
  Groundwater sources are found to be
under the direct influence of surface
water (GWUDI) if they exhibit specific
traits. The SWTR defined ground waters
containing Giardia lamblia as  GWUDI.
One such trait is the presence  of
protozoa such as Giardia which migrate
from surface water to groundwater. The
IESWTR expanded the SWTR's
definition of GWUDI to include the
presence of Cryptosporidium.  The
Agency believes it appropriate and
necessary to extend this modification of
the definition of GWUDI to systems
serving fewer than 10,000 persons.

b. Data
  The Agency issued guidance on the
Microscopic Particulate Analysis (MPA)
in October 1892 as the Consensus
Method for Determining Groundwater
Under the Direct Influence of Surface  ;
Water Using Microscopic Particulate
Analysis (EPA,  1992). Additional
guidance for making GWUDI
determinations is also available       •;
(USEPA, 1994a,b).  Since 1990, States
have acquired substantial experience in
making GWUDI determinations and
have documented their approaches
(Massachusetts Department of
Environmental Protection, 1993;
Maryland, 1993; Sonoma County Water'
Agency, 1991). Guidance on existing
practices undertaken by States in
response to the SWTR may also be
found in the State Sanitary Survey     •
Resource Directory, jointly published in
December 1995 by EPA and the
Association of State Drinking Water
Administrators (EPA/ASDWA).
AWWARF has also published guidance
(Wilson et al., 1996).
  Most recently, Hancock et al. (1997)
used the MPA test to study the
occurrence of Giardia and
Cryptosporidium in the subsurface.
They found that, in a study of 383
ground water samples, the presence of
Giardia correlated with the presence of
Cryptosporidium. The presence of both
pathogens correlated with the amount of
sample examined, but not with the
month of sampling. There was a
correlation between source depth and
occurrence of Giardia but not
Cryptosporidium. The investigators also
found no correlation between  the .
distance of the ground water source
from adjacent surface water and the
occurrence of either Giardia or
Cryptosporidium. However, they did
find a correlation between distance from
a surface water source and generalized
MPA risk ratings of high (high
represents an MPA score of 20 or
greater), medium or low, but no
correlation was found with the specific
numerical values that are calculated by  ,
the MPA scoring system. An additional
two reports (SAIC 1997a and I997b)
provide data on wells with Giardia cyst  .
and Cryptosporidium oocyst recovery
and concurrent MPA analysis.

c. Proposed Requirements
  In today's proposed rule, EPA is
modifying the definition of GWUDI to
include Cryptosporidium for systems
serving fewer than 10,000 persons.
  Under the SWTR, States were
required to determine whether systems
using ground water were using ground
water under the direct influence of
surface water (GWUDI). State
determinations were required to be
completed by June 29,1994 for CWSs
and by June 29,1999 for NCWSs. EPA
does not believe that it is necessary to
make a new determination of GWUDI
for this rule based on the addition of
Cryptosporidium to the definition of
"ground water under the direct
influence of surface water". While a
new determination is not required,
States may elect to conduct a new
analysis based on such factors as a new
land use pattern (conversion to dairy
farming, addition of septic tanks).
  EPA does not believe that a new
determination is necessary because the
current screening methods appear to
adequately address the possibility of
Cryptosporidium in the ground water.

d. Request for Comments
  The Agency requests comment on the
proposal to modify the definition of
GWUDI to include Cryptosporidium for
systems serving fewer than 10,000
persons.
2. Inclusion of Cryptosporidium
Watershed Requirements for Unfiltered
Systems
a. Overview and Purpose
  Existing SWTR requirements for
unfiltered surface water and GWUDI
systems require these systems to
minimize the potential for source water
contamination by Giardia lamblia and
viruses. Because Cryptosporidium has
proven resistant to levels of disinfection
currently practiced at systems
throughout the country, the Agency felt
it imperative to include
Cryptosporidium in the watershed
control provisions wherever Giardia
lamblia is mentioned. The IESWTR
therefore, modified existing watershed
regulatory requirements for unfiltered
systems to include the control of

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Federal  Register/Vol.  65, No. 69/Monday,  April 10, 2000/Proposed Rules
 Cryptosporidium. The Agency believes
 it appropriate and necessary to extend
 this requirement to systems serving
 fewer than 10,000 persons.
   It should be noted that today's
 proposed requirements do not replace
 requirements established for unfiltered
 systems under the SWTR. Systems must
 continue to maintain compliance with
 the requirements of the SWTR for
 avoidance of filtration. If an unfiltered
 system fails any of the avoidance
 criteria, that system must install
 filtration within 18 months, regardless
 of future compliance with avoidance
 criteria.
   EPA anticipates that in the planned
 Long Term 2 Enhanced Surface Water
 Treatment rule, the Agency will
 reevaluate treatment requirements
 necessary to manage risks posed by
 Cryptosporidium and other microbial
 pathogens in both filtered and unfiltered
 surface water systems. In conducting
 this reevaluation, EPA will utilize the
 results of several large surveys,
 including the Information Collection
. Rule (ICR) and ICR Supplemental
 Surveys, to more fully characterize the
 occurrence of waterborne pathogens, as
 well as watershed and water quality
 parameters which might serve as
 indicators of pathogen risk level. The
 LT2ESWTR will also incorporate the
 results of ongoing research on removal
 and inactivation efficiencies of
 treatment processes, as well as studies
 of pathogen health effects and disease
 transmission. Promulgation of the
 LT2ESWTR is currently scheduled for
 May, 2002.

 b. Data
   Watershed control requirements were
 initially established in 1989 (54 FR
 27496, June 29, 1989) (EPA, 1989b), as
 one of a number of preconditions that a
 public water system using surface water
 must meet to avoid filtration. The SWTR
 specifies the conditions under which a
 system can avoid filtration' (40 CFR
 141.71). These conditions include good
 source water quality, as measured by
 concentrations of coliforms and
 turbidity; disinfection requirements;
 watershed control; periodic on-site
 inspections; the absence of waterborne
 disease outbreaks; and compliance with
 the Total Coliform Rule and the MCL for
 TTHMs. The watershed control program
 under the SWTR must include a
 characterization of the watershed
 hydrology characteristics, land
 ownership, and activities which may
 have an advers9 effect on source water
 quality, and must minimize the
 potential for source water
 contamination by Giardia lamblia and
 viruses.
                       The SWTR Guidance Manual (EPA,
                     1991a) identifies both natural and
                     human-caused sources of contamination
                     to be controlled. These sources include
                     wild animal populations, wastewater
                     treatment plants, grazing animals,
                     feedlots, and recreational activities. The
                     SWTR Guidance Manual recommends
                     that grazing and sewage discharges not
                     be permitted within the  watershed of
                     unfiltered systems, but indicates that
                     these activities may be permissible on a
                     case-by-case basis where there is a long
                     detention time and a high degree of
                     dilution between the point of activity
                     and the water intake. Although there are
                     no specific monitoring requirements in
                     the watershed protection program, the
                     non-filtering utility is required to
                     develop State-approved  techniques to
                     eliminate or minimize the impact of
                     identified point and non-point sources
                     of pathogenic  contamination. The
                     guidance already suggests identifying
                     sources of microbial contamination,
                     other than Giardia, transmitted by
                     animals, and points out  specifically that
                     Cryptosporidium may be present if there
                     is grazing in the  watershed.

                     c. Proposed Requirements
                       In today's proposed rule, EPA is
                     extending the  existing watershed
                     control regulatory requirements for
                     unfiltered systems serving fewer than
                     10,000 people to include the control of
                     Cryptosporidium. Cryptosporidium will
                     be included in the watershed control
                     provisions for these systems wherever
                     Giardia lamblia is mentioned.
                       Specifically, the public water system
                     must maintain a watershed control
                     program which minimizes the potential
                     for contamination by Giardia lamblia,
                     and Cryptosporidium oocysts and
                     viruses in the water. The State must
                     determine whether the watershed
                     control program  is adequate to meet this
                     goal. The adequacy of a program to limit
                     potential contamination by Giardia
                     lamblia cysts,  Cryptosporidium oocysts
                     and viruses must be based on: The
                     comprehensiveness of the watershed
                     review; the effectiveness of the system's
                     program to monitor and  control
                     detrimental activities occurring in the
                     watershed; and the extent to which the
                     water system has maximized land
                     ownership and/or controlled land use
                     within the watershed.
                       It should be noted that unfiltered
                     systems must continue to maintain
                     compliance with the requirements of the
                     SWTR for avoidance of filtration. If an
                     unfiltered system fails any of the
                     avoidance criteria, that system must
                     install filtration within 18 months,
                     regardless of future compliance with
                     avoidance criteria.
d. Request for Comments

  EPA requests comment on the
inclusion of these requirements for
unfiltered systems serving fewer than
10,000 people.

3. Requirements for Covering New
Reservoirs
a. Overview and Purpose

  Open finished water reservoirs,
holding tanks, and storage tanks are
utilized by public water systems
throughout the country. Because these
reservoirs are open to the environment
and outside influences, they can be
subject to the reintroduction of
contaminants which the treatment plant
was designed to remove. The IESWTR
contains a requirement that all newly
constructed finished water reservoirs,
holding tanks, and storage tanks be
covered. The Agency believes it
appropriate and necessary to extend this
requirement to systems serving fewer
than 10,000 people.

b. Data

  Existing EPA  guidelines recommend
that all finished water reservoirs and
storage tanks be covered (EPA, 1991b).
The American Water Works Association
(AWWA) also has issued a policy
statement strongly supporting the
covering of reservoirs that store potable
water (AWWA,  1993). In addition, a
survey of nine States was conducted in
the summer of 1996 (Montgomery
Watson, 1996). The States which were
surveyed included several in the West
(Oregon, Washington, California, Idaho,
Arizona, and Utah),  two States in the
East known to have water systems with
open reservoirs  (New York and New
Jersey), and one midwestern State
(Wisconsin). Seven of the nine States
which were surveyed require by direct
rule that all new finished water
reservoirs and tanks be covered.
  Under the IESWTR, systems serving
populations of 10,000 or greater were
prohibited from constructing uncovered
finished water reservoirs after February
16, 1999. The Agency developed an
Uncovered Finished Water Reservoirs
Guidance Manual (USEPA, 1999f)
which provides  a basic understanding of
the potential sources of external
contamination in uncovered finished
water reservoirs. It also provides
guidance to water treatment operators
for evaluating and maintaining water
quality in reservoirs. The document
discusses:
  • Existing regulations and policies
pertaining to uncovered reservoirs;
  • Development  of a reservoir
management plan;

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                                                                    19097
  • Potential sources of water quality
degradation and contamination;
  • Operation and maintenance of
reservoirs to maintain water quality; and
  • Mitigating potential water quality
degradation.
  As discussed in the 1997 IESWTR
NODA (EPA, 1997b), when a finished
water reservoir is open to the
atmosphere it may be subject to some of
the environmental factors that surface
water is subject to, depending upon site-
specific characteristics and the extent of
protection provided. Potential sources
of contamination to uncovered
reservoirs and tanks include airborne
chemicals, surface water runoff, animal
carcasses, animal or bird droppings and
growth of algae and other aquatic
organisms due to sunlight that results in
biomass (Bailey and Lippy, 1978). In
addition, uncovered reservoirs may be
subject to contamination by persons
tossing items into the reservoir or illegal
swimming (Pluntze 1974; Erb, 1989).
Increases in algal cells, heterotrophic
plate count (HPC) bacteria, turbidity,
color, particle counts, biomass and
decreases in chlorine residuals have
been reported (Pluntze, 1974, AWWA
Committee Report, 1983, Silverman et
al., 1983, LeChevallier et al. 1997a).
  Small mammals, birds, fish, and the
growth of algae may contribute to the
microbial degradation of an open
finished water reservoir (Graczyk et al.,
1996a; Geldreich, 1990; Payer and
Ungar, 1986;). In one study, sea gulls
contaminated a 10 million gallon
reservoir and increased bacteriological
growth, and in another study waterfowl
were found to elevate coliform levels in
small recreational lakes by twenty times
their normal levels (Morra, 1979). Algal
growth increases the biomass in the
reservoir, which reduces dissolved
oxygen and thereby increases the release
of iron, manganese, and nutrients from
the sediments. This, in turn, supports
more growth (Cooke and Carlson, 1989).
In addition, algae can cause drinking
water taste and odor problems as well
as impact water treatment processes. A
1997 study conducted by the City of
Seattle (Seattle Public Utilities, 1997)
evaluated nutrient loadings by three
groups of birds at Seattle's open
reservoirs. Table IV.9 indicated the
amount of soluble nutrient loadings
estimated over the course of the year. It
shows that bird feces may contribute
nutrient loadings that can enhance algal
growth in the reservoir.
              TABLE IV.9.—1997 NUTRIENT LOADINGS BY BIRD GROUPS IN SEATTLE'S OPEN RESERVOIRS
Resea-oir
Beacon Hill* 	
Bitter Lake 	 	
Green Lake 	 	 	
Lake Forest , 	
Lincoln 	 	 	 	 , 	
Maple Leaf 	 	 	
Myrtle 	
Volunteer 	
West Seattle 	
Geese
Nitr.
kg/yr
0.00
0.82
1.78
2.23
0.00
2.16
0.00
0.00
0.40
Phos.
kg/yr
0.00
0.24
0.52
0.65
0.00
0.63
0.00
0.00
0.12
Gulls
Nitr.
kg/yr
0.00
0.01
0.03
0.36
0.24
0.13
0.08
0.01
0.38
Phos.
kg/yr
0.00
0.00
o.o'i
0.11
0.07
0.04
0.02
0.00
0.11
Ducks
Nitr.
kg/yr
0.00
0.06
0.53
0.07
0.01
0.35
,0.01
0.01
0.02
Phos.
kg/yr
0.00
0.02
0.16
0.02
0.00
0.10
0.00
0.00
0.01
Overall
Total
kg/yr
0.00
1.15
3.04
3.43
0.31
3.42
0.12
0.03
1.03
Cone.
(mg/L)
0.00
14.09
16.05'
15.09
3.96
15.43'
4.35
0.42
4;
c. Proposed Requirements
  In today's proposed rule EPA is
requiring surface water and GWUDI
systems that serve fewer than 10,000
people to cover all new reservoirs,
holding tanks or other storage facilities
for finished water for which
construction begins 60 days after the
publication of the final rule in the
Federal Register. Today's proposed rule
does not apply these requirements to
existing uncovered finished water
reservoirs.
d. Request for Comments
  EPA solicits comments regarding the
requirement to require that all new
reservoirs, holding tanks and storage
facilities for finished water be covered.
D. Recycle Provisions for Public Water
Systems Employing Rapid Granular
Filtration Using Surface Water and
GWUDI as a Source
  Section 1412(b)(14)  of the 1996
SDWA Amendments requires EPA to
promulgate a regulation to govern the
recycle of filter backwash within the
treatment process of public water
systems. "The Agency is concerned that
the recycle of spent filter backwash and
other recycle streams may introduce
additional Cryptosporidium oocysts to '
the treatment process. Adding oocysts to
the treatment process may increase the
risk oocysts will occur in finished water
supplies and threaten public health. The
Agency is further concerned because
Cryptosporidium is not inactivated by
standard disinfection practice, an
important treatment barrier employed to
control microbial pathogens. Oocysts
returned to the plant by recycle flow   ,
therefore remain a threat to pass through
filters into the finished water.
  The Agency engaged in three primary
information gathering activities to
investigate the potential risk posed by
returning recycle flows that may contain
Cryptosporidium to the treatment
process. First, die Agency performed a
broad literature search to gather
research papers and information on the
occurrence of Cryptosporidium and
organic and inorganic materials in
recycle flows.  The literature search also
sought information regarding the
potential impact recycle may have on
plant treatment efficiency. Second, the
Agency worked with AWWA,
AWWSCo., and Cincinnati Water Works
to develop twelve issue papers on
commonly generated recycle flows
(Environmental Engineering and
Technology, Inc.,1999). These papers
are summarized in the next section.
Information from EPA's literature search
was incorporated into the issue papers.
Third, the Agency presented
preliminary data and potential
regulatory components to stakeholders,
and solicited feedback, at public
meetings in Denver, Colorado, and
Dallas, Texas. EPA also received
valuable input from representatives of
small water systems through the
SBREFA process.
  Through the above activities, the
Agency has identified four primary
concerns regarding the recycle of spent
filter backwash and  other recycle
streams within the treatment process of
PWSs. The first concern is that some
recycle flows contain Cryptosporidium
oocysts, frequently at higher
concentrations than plant source waters.
Recycling these flows may increase the
number of oocysts entering the plant
and the number of oocysts reaching the
filters. Loading more oocysts to the     :

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filters could increase finished water
oocyst concentrations. The second
concern regards the location in the
treatment process recycle flow is
returned. The return of recycle at the
point of primary coagulant addition or
downstream of it may disrupt treatment
chemistry by introducing residual
coagulant or other treatment chemicals
to the process stream and thereby lower
plant treatment efficiency. Also, recycle
flow returned to the clarification
process may not achieve sufficient
residence time  for oocysts in the recycle
flow to be removed, or it may create
hydraulic currents that lower the unit's
overall oocyst removal efficiency. The
third concern regards  direct filtration
plants. Direct filtration plants do not
employ clarification in their primary
treatment process to remove suspended
solids and oocysts; all oocyst removal is
achieved by the filters. If the recycle
flow is not treated before being returned
to the plant, all of the oocysts captured
by a filter during a filter run will be
returned to the  plant and again loaded
to the filters. This may lead to ever
increasing levels of oocysts being
applied to the filters and could increase
the concentration of oocysts in finished
water. Therefore, it is  important for
direct filtration plants to provide
adequate recycle flow treatment to
remove oocysts and protect the integrity
of the filters and finished water quality.
Finally, the fourth concern is that the
direct recycle of spent filter backwash
without first providing treatment,
equalization, or some form of hydraulic
detention for the recycle flow, may
cause plants to  exceed State-approved
operating capacity during recycle
events. This can cause clarification and
filter loading rates to be  exceeded,
which may lower overall oocyst removal
provided by the plant and increase
finished water oocyst concentrations.
  EPA has particular concerns regarding
the direct recycle of spent filter
backwash water as it is produced (i.e.,
recycle flow is not retained in an
equalization basin, treatment unit, or
oilier hydraulic detention unit prior to
reintroduction to the main treatment
process) for the following reasons:
  (1) Direct recycle may cause operating
rates for clarification and filtration to be
exceeded, which may  lower overall
Cryptosporidium removal;
  (2) Direct recycle may hydraulically
upset some plants, lowering overall
plant treatment performance, and;
  (3) Clarification and filtration
operating rates may be exceeded at
precisely the time recycle flow may be
returning large numbers of oocysts to
the treatment process.
                       The impact of direct recycle practice
                     to smaller plants with few filters is of
                     greatest concern because return of
                     recycle flow can double or triple plant
                     influent flow, which may hydraulically
                     overload the plant and reduce oocyst
                     removal.
                       Since standard disinfection practice
                     does not inactivate Cryptosporidium, its
                     control is entirely dependent on
                     physical removal processes. The Agency
                     is concerned that direct recycle may
                     cause some plants to exceed operating
                     capacity and thus lower their physical
                     removal capabilities. This can increase
                     the risk of oocysts entering the finished
                     water and lead to an increased risk to
                     public health.
                       The limited data (Cornwell and Lee,
                     1993) EPA has identified regarding
                     plants with existing equalization and/or
                     treatment indicates they may be at no
                     greater risk of hydraulic upset or
                     degradation of oocyst removal
                     performance than non-recycle plants.
                     Given current data limitations, it is
                     reasonable to assume the presence and
                     utilization of adequate recycle flow
                     equalization and/or treatment processes
                     will alleviate the potential for hydraulic
                     disruptions and the impairment of
                     treatment performance. Data suggesting
                     otherwise is currently unavailable.
                       The potential for recycle to return
                     significant numbers of oocysts to the
                     treatment train does provide a general
                     basis for concern regarding the impact
                     of recycle practice to finished water
                     quality. However, the Agency does  not
                     currently believe data warrants a
                     national regulation requiring all recycle
                     plants to provide recycle flow
                     equalization or treatment for the
                     following reasons:
                       (1) Data correlating oocyst occurrence
                     in recycle streams to increased oocyst
                     occurrence in finished water is
                     unavailable;
                       (2) Data regarding the response of full-
                     scale plants to recycle events is limited;
                       (3) Data is not available to determine
                     the level of recycle flow equalization or
                     treatment full-scale systems may need,
                     if any, to control the risk of oocysts
                     entering finished water, and;
                       (4) Whether and the extent to which
                     oocyst occurrence in source water
                     influences the necessary level of recycle
                     treatment and equalization is unknown.
                       The Agency believes requiring plants
                     that may be at greater risk due to
                     recycle, such as direct recycle plants
                     and direct filtration plants, to
                     characterize their recycle practice and
                     provide data to the State for its review
                     provides a cost effective opportunity to
                     increase public health protection and
                     supply a measure of safety to finished
                     drinking water supplies. EPA believes
 that today's proposal will address
 potentially higher risk recycle situations
 that may threaten the performance of
 some systems, and will do so by
 allowing State drinking water programs
 to consider site-specific treatment
 conditions and needs. The Agency
 believes these recycle provisions are
 needed to protect plant performance,
 the quality of finished water supplies,
 and to provide an additional measure of
 public health protection.

 1. Treatment Processes That Commonly
 Recycle and Recycle Flow Occurrence
 Data
 a. Treatment Processes That Commonly
 Recycle
   The purpose of this section is to
 provide general background on common
 treatment plant processes, fundamental
 plant operations, and the origin of plant
 recycle streams. Detailed information on
 the specific recycle flows these
 processes generate are presented after
 this background discussion. Four
 general types of water treatment
 processes, conventional filtration, direct
 filtration, softening, and contact
 clarification, are discussed. Although
 there are numerous variations of these
 four treatment processes, only the most
 basic configurations are discussed here.
 The operation of package plants and
 options to returning recycle to the
 treatment process are also summarized.

 i. Conventional Treatment Plants
  Conventional water filtration plants
 are defined by the use of four essential
 unit processes: Rapid mix, coagulation/
 flocculation, sedimentation, and
 filtration. Sedimentation employs
 gravity settling to remove floe and
 particles. Particles not removed by
 sedimentation may be removed by the
 filters. Periodically, accumulated solids
 must be removed from the
 sedimentation unit. These solids,
 termed "residuals," are currently
 disposed to sanitary sewer, treated with
 gravity thickening, or some other
 process prior to returning them to plant
 headworks or other locations in the
 treatment train. Clarification processes
 other than sedimentation may also be
 used, and they also produce process
 residuals.
  Clarification sludge may be processed
 on-site if the plant is equipped with
 solids treatment facilities.  Commonly
 employed treatment processes include
 thickeners, dewatering equipment (e.g.,
 plate and frame presses, belt filter
 presses, or centrifuges), and lagoons.
Each of these processes produces
residual water streams that are currently
returned to the treatment process at the

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                                                                     19099
headworks or other locations prior to
filtration. The volume of residuals
produced by clarification depends upon
the amount of solids present in the raw
water, the dose and type of coagulant
applied, and the concentration of solids
in the treated water stream.
  The one residual stream associated
with filtration, spent filter backwash
water, is produced during periodic
backwashing events performed to
remove accumulated solids from the
filter. Spent filter backwash is
frequently returned to the treatment
process at the head of the plant, other
locations prior to the filters, or disposed
of to sanitary sewer or surface water.
Some plants have the capability to send
the filtrate produced during the filter
ripening period to plant headworks, a
raw water reservoir, or to a sanitary
sewer or surface water rather than to the
clear well as finished water. This
practice, referred to as "filter-to-waste"
is used to prevent solids, which pass
through the filter more easily during the
ripening period, from entering the
finished water.
   Filter backwash operations can differ
significantly from plant to plant. The
main variables  are the time between
backwashes (length of filter run), the
rate of backwash flow, the duration of
the backwash cycle, and the
backwashing method. The time between
filter backwashes is generally a function
of either run time, headless, or solids
breakthrough. Both headloss and solids
breakthrough can be dependent upon
the quality of the sedimentation
effluent. Regardless of the variable
driving backwash frequency, the
interval between backwashes typically
vary from 24 to 72 hours. Recommended
backwash frequency is every 24-48
hours (ASCE/AWWA, 1998).
   There are a number of different
methods that can be used to backwash
a filter. These include: Upflow water
only, upflow water with surface wash,
and air/water backwash. Air/water
backwash systems typically use 30-50
percent less water than the other two
methods. The filter backwash flow rate
can vary, depending on media type,
water temperature, and backwash
method, but generally has a maximum
of 15-23 gpm/ftz (air/water backwash
may have a lower maximum rate of 6-
7 gpm/ft2). A number of different
backwash sequences are employed, but
a typical backwash consists of a low rate
wash (6-7 gpm/ft2 for several minutes),
followed by a high rate wash (15-23
gpm/ft2 for 5-15 minutes), which is
then followed by a final low rate wash
(6-7 gpm/ft2 for several additional
minutes). Some treatment plants only
use a high rate  wash for 15 to 30
minutes. Backwash rates are
significantly higher than filtration rates,
which vary from 1 to 8 gpm/ft2.
ii. Direct Filtration Plants
  The direct filtration process is similar
to conventional treatment, except the
clarification process is not present.
Direct filtration plants produce the same
filter residual as conventional filtration
plants, namely filter backwash, and may
also generate a filter-to-waste flow.
Direct filtration plants do not produce
clarification residuals because
clarification is not employed. Filter
backwash may be either recycled to the,
head of the plant or discharged to
surface waters or a sanitary sewer.
Although direct filtration plants
generally treat source waters that have •
low concentrations of suspended
material, the solids loading to the filters
may be higher than at conventional
plants because solids are not removed in
a clarification process prior to filtration.
If spent filter backwash is not treated to
remove solids prior to recycle, solids
loading onto the filters will continue to
increase over time, as an exit from the
treatment process is unavailable. Filter
run length may be shorter in some direct
filtration plants relative to conventional
plants because the solids loading to the
filters may be higher due to the lack of
a clarification process. The
concentration of solids in the source   ,
water is a key variable in filter run
length.
iii. Softening Plants
  Softening plants utilize the same basic
treatment processes as conventional
treatment plants. Softening plants
remove hardness (calcium and
magnesium ions) through precipitation,
followed by solids removal. Many
softening plants employ a two-stage
process, which consists of a rapid mix-
flocculation-sedimentation sequence, in
series, followed by filtration. Others use
a single stage process, resembling
conventional treatment plants.
Precipitation of the calcium and
magnesium ions is accomplished
through the addition of lime (calcium
hydroxide), with or without soda ash
(sodium carbonate), which reacts with
the calcium and magnesium ions in the
raw water to form calcium carbonate
and magnesium hydroxide. The
precipitation of the calcium carbonate
can be improved by recirculating some
of the calcium carbonate sludge into the
rapid mix unit because the additional
solids provide nucleation points for the
precipitation of calcium and
magnesium. Without this recirculation,
additional hydraulic detention time in;
the flocculation and sedimentation
basins may be required to prevent
excessive scale deposits in the plant
clearwell or in the distribution system.
  A softening plant generally has the
same residual streams as a conventional
plant: Filter backwash, sedimentation
solids, and thickener supernatant and
dewatering liquids. A filter-to-waste
flow may also be generated. These
residual streams are either disposed or
recycled within the plant. A portion of
the sedimentation basin solids are
commonly recycled as the
sedimentation basin solids contain
significant quantities of precipitated
calcium carbonate, recycle of these
solids reduces the required chemical
dose.  Solids are generally recycled into
the rapid mix chamber to maximize
their effectiveness.

iv. Contact Clarification Plants

  In the contact clarification process,
the flocculation and clarification (and
often  the rapid mix) processes are
combined in one unit, an upflow solids
contactor or contact clarifier. Contact
clarifiers are  employed in both softening
and non-softening processes. Raw water
flows into the contact clarifier at the top
of the central compartment, where
chemical addition and rapid mix occurs.
The water then flows underneath a skirt
and into the outer sedimentation zone
where solid separation occurs. A large
portion of previously settled solids from
the sedimentation zone is circulated to
the mixing zone to enhance
flocculation. The remainder of the
solids are disposed to prevent their
accumulation. Circulation and disposal
of accumulated solids allows clarifier
loading rates to be 10 to  20 times greater
than loading rates for conventional
sedimentation basins. Solids
recirculation rates are generally
different for softening and turbidity
removal applications, with rates of up to
12 times the raw water flow for
softening processes and  up to 8 times
the raw water flow for non-softening
processes (ASCE/AWWA, 1998).
Following clarification, treated water
from  the contactor is then filtered.
  The residual streams from contact
clarification plants are similar to those
for conventional filtration plants.  They
include filter backwash, clarification
solids, thickener supernatant, and
dewatering liquids. The key operational
consideration for these types of systems
is the maintenance of a high
concentration of solids within the skirt
to allow high loading rates while
maintaining adequate solids removal.
Solids recirculation (e.g., recycle)  helps
contact clarification processes maintain
the necessary solids concentration.

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Federal Register/Vol.  65, No. 69/Monday, April  10,  2000/Proposed Rules
 Softening plants may also generate filter
 to waste flow.

 v. Package Plants

  Package plants are typically used to
 produce between a few thousand to 1
 million gallons of water per day.
 Package plants can employ a
 conventional treatment train, as well as
 proprietary unit processes. Package
 plants typically include the same
 processes found in large plants,
 including coagulation, flocculation,
 clarification and filtration. The potential
 recycle streams are also comparable.
 The recycle of filter backwash may
 occur, however, the typical package
 plant may not be designed to convey
 process streams back into the plant as
 recycle.

 vi. Summary of Recycle Disposal
 Options

  Two recycle disposal options
 available to some plants are direct
 discharge to sanitary sewers or
 discharge to surface waters. Discharge of
 recycle waters to the municipal sewer
 system may occur when the treatment
 plant and Publicly Owned Treatment
 Works (POTW) are under the same
 authority or when the plant has access
 to a sanitary sewer and a POTW agrees
 to accept its discharge.
  There may be a fee associated with
 discharge to a sanitary sewer system,
 and the total fee may vary with the
 volume of backwash effluent discharged
 as well as the amount of solids in the
 effluent (Cornwell and Lee, 1994). In
 addition to the fee requirement,
 discharging into the sewer system may
 require the plant to equalize the effluent
 prior to discharging to the POTW. The
 equalization process requires holding
 the effluent in tanks and gradually
 releasing it into the sanitary sewer
 system. The fee associated with sanitary
 sewer discharge may influence whether
 a plant recycles to the treatment process
 or discharges to a sanitary sewer.
  Another option to recycle within the
 treatment process is the direct discharge
 of recycle flow to surface waters, such
 as creeks, streams, rivers, and reservoirs.
 Direct discharge is a relatively common
 method of disposal for water treatment
 plant flows. A National Pollutant
 Discharge Elimination System (NPDES)
 permit requires that certain water
 quality conditions be met prior to the
 discharge of effluent into surface waters.
 Treatment of the effluent prior to
 discharge may be required. The cost of
 effluent treatment may influence
whether plants recycle within the
treatment process or discharge to
 surface water.
                     b. Recycle Flow Occurrence Data
                       EPA has not regulated recycle flows
                     in previous rulemakings. The 1996
                     SDWA Amendments have lead the
                     Agency to perform an examination of
                     recycle flow occurrence data for the first
                     time. EPA discovered through its
                     literature search and its work with
                     AWWA, AWWSCo., and Cincinnati
                     Water Works to develop the issue
                     papers, that the amount of recycle
                     stream occurrence data available is very
                     limited, particularly for
                     Cryptosporidium, the primary focus of
                     this regulation. This may be because
                     Cryptosporidium was identified as a
                     contaminant of concern relatively
                     recently and because currently available
                     oocyst detection methods have
                     limitations.
                       Twelve issue papers were developed
                     to compile information on several
                     commonly produced recycle streams.
                     Each individual paper summarizes how
                     the recycle stream is generated, the
                     typical volume generated, characterizes
                     the occurrence of various recycle stream
                     constituents to the extent data allows,
                     (i.e., occurrence of Cryptosporidium and
                     inorganic and organic material), and
                     briefly discusses potential impacts of
                     recycling the stream. The discussion of
                     potential impacts is usually brief, due to
                     overall data limitations and particularly
                     due to a lack of data on
                     Cryptosporidium occurrence. The 12
                     recycle streams examined include:
                       •  untreated spent filter backwash
                     water
                       •  gravity settled spent filter backwash
                     water
                       •  combined gravity thickener
                     supernatant (spent filter backwash and
                     clarification process solids)
                       •  gravity thickener supernatant from
                     sedimentation basin solids
                      •  mechanical dewatering device
                     concentrate
                      •  untreated basin solids
                      •  lagoon decant
                      •  sludge drying bed leachate
                      •  monofill leachate membrane
                     concentrate
                      •  ion exchange regenerate
                      •  minor streams
                      A total of 112 references were used to
                     complete the issue papers, and
                     AWWSCo. and Cincinnati Water Works
                     performed sampling of non-microbial
                     recycle stream constituents to
                     supplement occurrence information.
                      Cryptosporidium occurrence data was
                     only identified for five recycle streams,
                     namely: untreated spent filter backwash
                     water, gravity settled spent filter
                     backwash water, untreated
                     sedimentation basin solids, combined
                     thickener supernatant, and sludge
 drying bed leachate. Oocysts may occur
 in the other recycle streams as well, but
 published occurrence data was not
 identified. The issue papers and
 supporting literature indicate data does
 not exist to correlate oocyst occurrence
 in recycle streams to the occurrence of
 oocysts in finished water. However, the
 issue papers did identify data showing
 that oocysts occur in recycle streams,
 often at concentrations higher than that
 of the source water.
  Cryptosporidium is not the only
 constituent of recycle waters. Other
 common constituents are manganese,
 iron, aluminum, disinfection
 byproducts, organic carbon, Giardia
 lamblia and particles. EPA does not
 currently have data to indicate these
 constituents occur in recycle streams at
 levels which threaten treatment plant
 performance, finished water quality, or
 public health. Additionally, current
 regulations may largely control any
 minor risk these constituents may
 present. For example, organic matter in
 recycle flow may form disinfection
 byproducts in the presence of oxidants.
 The Stage 1 DBPR, which requires
 monitoring for disinfection byproducts,
 will identify systems experiencing
 disinfection byproduct occurrence
 above or near applicable MCLs through
 distribution system monitoring.
 Additionally, Secondary Maximum
 Contaminant Levels (SMCLs) have been
 promulgated to control occurrence of
 aluminum, iron, and manganese at
 levels of .05-.2 mg/1, .3 mg/1, and .05
 mg/1, respectively. Particle levels are
 controlled by effluent turbidity
 standards and Giardia lamblia is
 controlled through a combination of
 disinfection and filtration requirements.
 EPA believes existing regulations
 control these recycle stream
 constituents. Therefore, their control is
 not a primary goal of today's proposal.
 Additionally, detailed discussion of
 these constituents is not provided in the
 below summary of the issue papers
 because: (1) control of Cryptosporidium
 is the focus of the recycle provisions,
 and; (2) concentrations of inorganic and
 organic materials  reported in lie issue
 papers are for recycle streams, not
 finished water occurrence. The recycle
 stream concentrations will be
 significantly diluted by mixing with
 source water.
  The occurrence of recycle flow
 constituents other than
 Cryptosporidium is not discussed in
 today's preamble for the above reasons.
 The following discussion of recycle
 stream occurrence data covers only
 untreated  spent filter backwash water,
gravity settled spent filter backwash
 water, combined gravity thickener

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                  Federal Register/Vol.  65,  No. 69/Monday,  April 10, 2000/Proposed  Rules
                                                                     19101
supernatant (a combination of spent
filter backwash and clarification process
solids), gravity thickener supernatant
from clarification process solids, and
mechanical dewatering device liquids.
These five recycle streams are discussed
in detail because they are most likely to
present a threat to treatment plant
performance or finished water quality
when recycled. For example, treated
and untreated spent filter backwash
water and thickener supernatant are the
only two recycle streams of sufficient
volume to cause plants to exceed their
operating capacity during recycle
events. The five recycle streams
discussed below are also most likely to
contain Cryptosporidium.
  Copies of all the issue papers are
available for public review in the Office
of Water docket for this rulemaking.
Portions of the following recycle stream
descriptions use excerpts from the issue
papers.
/. Untreated Spent Filter Backwash
Water
  Water treatment plants that employ
rapid granular filtration (e.g.,
conventional, softening, direct filtration,
contact clarification) generate spent
filter backwash water. The backwash
water is generated when water is forced
through the filter, counter-current to the
flow direction during treatment
operations, to dislodge  and remove
accumulated  particles and pathogens
residing in the filter media. Backwash
rates are typically five to eight times the
process rate, and are used to clean the
filter at the end of a filter run, which is
generally 24 to 72 hours in length.
Backwash operations usually last from
10 to 25 minutes. The flow rate and
duration of backwashing are the primary
factors that determine the volume of
backwash water produced. Once the
backwashing process is complete, the
backwash water and entrained solids are
either  disposed of to a sanitary sewer,
discharged to a surface water, or
returned to the treatment process. Plants
currently return spent filter backwash to
the treatment process at a variety of
locations, usually between plant
headworks and clarification. Data
regarding common recycle return
locations is discussed in the next
section of this preamble.
  Spent filter backwash can be returned
to the treatment process directly as it is
produced, be detained  in an
equalization basin, or passed through a
treatment process, such as clarification,
prior to being returned to the plant. On
a daily basis, spent filter backwash can
range from 2  to 10 percent of plant
production. Spent filter backwash is
usually produced on an intermittent
basis, but large plants with numerous
filters may produce it continuously. At
small and mid-size plants, large volume,
short duration flows of spent filter
backwash are usually produced. This
may cause some plants, particularly
smaller plants that recycle directly
without flow equalization or treatment,
to exceed their operating capacity or to
experience hydraulic disruptions, both
of which may negatively impact
treatment efficiency and oocyst removal.
  The concentrations of            :
Cryptosporidium reported in the
untreated spent filter backwash issue
paper ranges from non-detect to a
concentration of 18,421 oocysts per 100
L. This range is not amenable to formal
statistical analysis, but rather provides a
summary of minimum and maximum
oocyst concentrations reported in
available literature. Although a few
studies report isolated data points of
  freater than 10,000 oocysts/lOOL for
  Iter backwash water (Rose et al., 1989;
Cornwell and Lee, 1993; Colbourne,
1989), occurrence studies that collected
the largest number of samples reported
mean filter backwash oocyst occurrence
concentrations of a few hundred oocysts
per 100L (States et al., 1997; Karanis et
al., 1996). The high concentration of
oocysts found in some spent filter
backwash samples is cause for concern,
because oocysts are not inactivated by
standard disinfection practice. They
remain a threat to pass through the plant
into the finished water if they are
returned to the treatment process.
However, current oocyst detection
methods do not allow the occurrence of
oocysts in spent filter backwash water to
be correlated to finished water oocyst
concentrations for a range of plant
types, source water qualities, and
recycle practices. Today's proposal does
not require the installation of recycle
equalization or treatment for spent filter
backwash water on a national basis due
to these data limitations.
  The Agency is concerned that certain
recycle practices, such as returning
spent filter backwash to locations other
than prior to the point of primary
coagulant addition, or hydraulically
overloading the plant with recycle flow
so it exceeds its State approved
operating capacity, may present risk to
finished water quality and public    :
health. Exceeding plant operating
capacity during recycle events may
cause greater risk to finished water
quality, because plant performance is
potentially being lowered at precisely
the time oocysts are returned to the  ;
plant in the recycle flow. To address
this concern, today's proposal requires
that certain  direct recycle plants that
recycle spent filter backwash water and/
or thickener supernatant to perform a
self assessment of their recycle practice
and report the results to the State. The
self assessment requirements are
discussed in detail later in this
preamble.
ii. Gravity Settled Spent Filter Backwash
Water
  Gravity settled spent filter backwash
water is generated by the same filter
backwash process and is produced in
the same volume as untreated spent
filter backwash water. The difference
between the two streams is that the
former is treated by gravity settling prior
to its return to the primary treatment
process. Sedimentation treatment is
usually accomplished by retaining the
spent filter backwash water in a
treatment unit for a period of time to
allow suspended solids (including
oocysts) to  settle to the bottom of the
basin. Polymer may be used to improve
process efficiency. The water that leaves
the basin is gravity settled spent filter
backwash water. Removing solids from
the spent filter backwash causes only a
minor reduction in volume as the solids
content of the untreated  stream is low,
usually below 1 percent.
  Providing gravity settling for spent
filter backwash is advantageous for two
reasons. First, the sedimentation process
detains the spent filter backwash in
treatment basins for a period of hours,
which lowers the possibility a large
recycle volume will be returned to the
plant in a short amount of time and
cause the plant operating capacity to be
exceeded. Second, treating the spent
filter backwash flow can remove
Cryptosporidium oocysts from the flow,
which will reduce the number of
oocysts returned to the plant.
  Limited data show that sedimentation
can effectively remove oocysts.
Cornwell and Lee (1993) conducted
limited sampling of spent filter
backwash water at two plants prior to
and after sedimentation treatment. The
first facility-practiced direct filtration
and was sampled twice.  The
Cryptosporidium concentrations into
and out of the sedimentation basin
treating spent filter backwash were 900/
100L and 140/100L, respectively, for the
first sampling and 850/100L in the
influent and 750/100L in the effluent for
the second sampling. At the second
plant a sludge settling pond received
both sedimentation basin sludge and
spent filter backwash, and the spent
filter backwash oocyst concentration
was 16,500/lOOL, and the treated
recycle water concentration was 420/
100L. In a study by Karanis (1996),
Cryptosporidium was regularly detected
in settled backwash waters. Of the 50

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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
samples collected, 82 percent tested
positive for Cryptosporidium. The mean
value for Cryptosporidium was 22
oocysts/lOOL.
  Sedimentation treatment can remove
oocysts from spent filter backwash, but
data indicate oocysts remain in gravity
settled spent filter backwash water even
after treatment. The Agency believes
that sedimentation treatment for spent
filter backwash waters is capable of
removing oocysts and improving the
quality of the water prior to recycle.
However, given current data limitations,
the Agency does not believe it is
possible to specify, in a national
regulation, the conditions (e.g., source
water oocyst concentrations, primary
treatment train performance,
concentration of oocysts in spent filter
backwash, ability of sedimentation to
remove oocysts under a range of
conditions) under which sedimentation
treatment of spent filter backwash water
may be appropriate. This decision is
best made by State programs to allow
consideration of site-specific conditions
and treatment needs.

Hi.  Combined Gravity Thickener
Supernatant
  Combined gravity thickener
supernatant is derived from the
treatment of filter backwash water and
sedimentation basin solids in gravity
thickener units. These two flows may
not reside in the thickener at the same
time or in equal volumes, depending on
plaint operations. The volume of
thickener supernatant generated at a
water treatment plant is a function of
the type of flows it treats,- the solids
content of the influent stream, and the
method of thickener operation.
Regardless of whether a continuous or a
batch process is used, a number of
factors, including residuals production
(a function of plant production, raw
water suspended solids, and coagulant
dose), volume of spent filter backwash
water produced, and the level of
treatment provided to thickener influent
streams, directly affect the quantity of
thickener supernatant produced.
  The flow entering the thickener is
primarily spent filter backwash water.
Sedimentation basin solids is the
second largest flow. Flow from
dewatering devices, which is generated
by the dewatering of residuals, may
comprise a minor volume entering the
thickener. Combined thickeners will
have an influent that may be eighty-
percent spent filter backwash or more
by volume. About eighty-percent of the
solids entering the thickener will be
from the sedimentation basin sludge, as
spent filter backwash water has a
comparatively low solids concentration.
                       A recent FAX survey (AWWA, 1998)
                     identified more than 300 water
                     treatment plants in the United States
                     with production capacities ranging from
                     less than 2 mgd to greater than 50 mgd
                     that recycle spent filter backwash water.
                     Many of the survey respondents
                     indicated that they recycle more than
                     just spent filter backwash water. Based
                     on the survey and published literature,
                     thickener supernatant is probably the
                     second largest and second most
                     frequently recycled stream at water
                     treatment facilities after spent  filter
                     backwash.
                       Data summarized in the issue paper
                     showed that thickener supernatant
                     quality varies widely, due in large part
                     because the type and quality of recycle
                     streams entering thickeners varies over
                     time and from plant to plant. The
                     turbidity, total suspended solids, and
                     particle counts of thickener effluent are
                     directly impacted by the quality of
                     water loaded onto the thickener,
                     thickener design, and thickener
                     operation (e.g., residence time, use of
                     polymer).
                       Data on the occurrence of
                     Cryptosporidium was limited to two
                     samples, with oocyst occurrence ranging
                     from 82 to 420 oocysts per 100 L. Data
                     is too limited, and practice varies too
                     widely, to draw conclusions on the
                     impact recycle of this flow may have on
                     plant performance. However, given that
                     the contents of the thickener have been
                     treated and the amount of flow
                     produced by gravity thickeners is
                     relatively modest, it may be feasible to
                     recycle the flow in a manner that
                     minimizes adverse impact.
                     Additionally, treatment plant personnel
                     have a vested interest in optimizing
                     thickener operation to minimize sludge
                     dewatering and handling costs;
                     optimization of thickener operation is
                     likely to assist oocyst removal.
                     However, additional data is needed to
                     characterize the occurrence of
                     Cryptosporidium and the potential
                     impact recycle of combined thickener
                     supernatant may have on finished water
                     quality.

                     iv. Gravity Thickener Supernatant from
                     Sedimentation Solids
                       Gravity settled sedimentation basin
                     solids are sedimentation basin solids
                     that have undergone settling to allow
                     solid sludge components to settle to the
                     bottom of a gravity thickener. The
                     supernatant from the thickener is a
                     potential recycle flow. The tank bottom
                     is sloped to enhance solids thickening
                     and collection and removal of settled
                     solids is accomplished with a bottom
                     scraper mechanism. If the supernatant  is
                     recycled, it can be returned to the plant
continuously or intermittently,
depending on whether the thickener is
operated in batch mode. Thickeners
may receive and treat both spent filter
backwash water and sedimentation
basin solids. For purposes of this
discussion, and the data presented in
the issue paper, the gravity thickener is
only receiving sedimentation basin
solids.
  The volume of treated sedimentation
basin solids supernatant generated is
dependent on the amount of sludge
produced in the sedimentation basin,
the solids content of the sludge, and
method of thickener operation. Sludge
production is a function of plant
production, raw water suspended
solids, coagulant type, and coagulant
dose. The quantity of sedimentation
basin sludge supernatant is
approximately 75 to 90 percent of the
original volume of sedimentation basin
sludge produced.
  There is a very limited amount of data
on the quality of thickener supernatant
produced by gravity settling of only
sedimentation basin solids (i.e., spent
filter backwash and other flows are not
added to the thickener), and no data was
identified regarding the concentration of
Cryptosporidium that occur in the
supernatant. As is the case with
combined gravity thickener supernatant,
it is difficult to determine what impact,
if any, the return of the supernatant may
have on plant operations and finished
water quality due to limited data.
Additional data is necessary to
determine the concentration of oocysts
in this recycle stream, and to
characterize the impact its recycle may
have to plant performance.
v. Mechanical Dewatering Device
Liquids
  Water treatment plant residuals
(usually thickened sludge) are usually
dewatered prior to disposal to remove
water and reduce volume. Two common
mechanical dewatering devices used to
separate solids from water are the belt
filter press, which compresses the
residuals between two continuous
porous belts stretched over a series of
rollers, and the centrifuge, which
applies a strong centrifugal force to
separate solids from water. The plate
and frame press is another dewatering
device that contains a series of filter
plates, supported and contained in a
structured frame, which separate sludge
solids from water using a positive
pressure differential as the driving force.
Water removed from the solids with a
belt filter press is called filtrate, from a
filter press it is called pressate, and the
water separated from the residuals  with
a centrifuge is referred to as centrate.

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                                                                     19103
These streams will be collectively
referred to as "dewatering liquid" for
the following discussion.
  The volume of dewatering liquid
produced depends primarily on the
volume and solids content of the
thickened residuals fed to the
mechanical dewatering device. Plants
that produce small sludge volumes, and
hence a low volume of thickener
residuals, will process fewer residuals
in the mechanical dewatering device
and hence produce a smaller volume of
dewatering liquid than a plant
producing a large volume of solids, all
else being equal. Since residuals are
often thickened (typically to about 2 •<,
percent solids) prior to dewatering, the
volume of the dewatering device feed
stream is significantly lower than the
volume of sedimentation basin residuals
generated. If the sedimentation basin
sludge flow is assumed to be 0.6 percent
of plant production, then dewatering
device flow may be approximately 0.1 to
0.2 percent of plant flow. Generally
these streams are mixed in with other
recycle streams prior to being returned
to the plant. Mechanical dewatering
devices may be operated intermittently,
after a suitable volume of residuals have
been produced for dewatering. The
production of dewatering liquid and its
recycle may not be a continuous
process.
  Data on the constituents in
dewatering liquid were found in three
references, one on belt filter press
liquids, one on plate and frame pressate,
and one on centrifuge centrate. Data on
the occurrence of Cryptosporidium was
not identified. Given the small,
intermittent flow produced by
mechanical dewatering devices, recycle
flows from them are unlikely to cause
plants to exceed operating capacity.
However, it is possible that dewatering
device liquid contains Cryptosporidium
because it derived from solids likely to
hold a large numbers of oocysts.
Additional data is necessary to
determine the concentration of oocysts
in this recycle stream, and to
characterize any impact its recycle may
have to plant performance.

2. National Recycle Practices
a. Information Collection Rule

  Public water systems affected by the
ICR were required to report whether
recycle is practiced and sample
washwater (i.e., recycle flow) between
the washwater treatment plant (if one
existed) and the point at which recycle
is added to the process train. Sampling
of plant recycle flow was required prior
to blending with the process train.
Monthly samples were required for pH,
alkalinity, turbidity, temperature,
calcium and total hardness, TOG, UV254,
bromide, ammonia, and disinfectant
residual if disinfectant was used.
Systems were also required to measure
recycle flow at the time of sampling, the
twenty four hour average flow prior to
sampling, and report whether treatment
of the recycle was provided and, if so,
the type of treatment. Reportable
treatment types were plain
sedimentation, coagulation and
sedimentation, filtration, disinfection,
or a description of an alternative
treatment type. Plants were also
required to submit a plant schematic to
identify sampling locations. EPA used
the sampling schematics and other
reported information to compile a
database of national recycle, practice.

i. Recycle Practice

  The Agency developed a database
from the ICR sampling schematics and
other reported information.  Table IV.10
summarizes the plants in the database.
Of the 502 plants in the database at the
time the analysis was performed, 362
used rapid granular filtration.

TABLE IV. 10.—RECYCLE PRACTICE AT
             ICR PLANTS
Plant classification
All ICR plants
Filtration plants a 	
Filtration plants recycling b
Filtration plants treating recycle 	
Recycle plants serving 5100,000 	
Recycle plants serving <1 00,000 	
Num-
ber
502
362
226
148
168
58
  "Defined as conventional,  lime softening,
other softening, and direct filtration plants.
  b Plants report  existence  of a  recycle
stream, not its origin.

  These plants are classified as
conventional, lime softening, other
softening, and direct filtration. The
remaining 140 plants in the database do
not employ rapid granular filtration
capability and generally provide
disinfection for ground water. Of the
362 filtration plants in the database, 226
(62.4 percent) reported recycling to the
treatment process. Seventy-four percent
of the plants that recycle serve
populations greater than 100,000 and 26
percent serve populations below
100,000. Figure IV.9 shows the
distribution of plants by treatment type
and Figure IV. 10 shows the distribution
of plants by population served. Table
IV. 11 shows that 88  percent of ICR
recycle plants use surface water. An
additional one percent use GWUDI and
another one percent use a combination
of ground water and surface water.
Therefore, 90 percent of ICR recycle
plants use a source water that could
contain Cryptosporidium,
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19104
Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
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19106
Federal  Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed Rules
                           TABLE iv.11.—SOURCE WATER USE BY ICR RECYCLE PLANTS
Source water type




Ground water only 	
Number of
plants
226
199
3
2
22
Percent of
recycle
plants
100
88
1
1
10
  Table IV. 12 shows that 65 percent of
ICR recycle plants report providing
treatment for the recycle flow. The
percentage of plants providing treatment
is the same for the subsets of plants
                     serving greater than and less than
                     100,000 people. Sedimentation is the
                     most widely reported treatment method,
                     as 77 percent of plants providing
                     treatment employ it. The database does
not provide information on the solids
removal efficiency of the sedimentation
units. All direct filtration plants
practicing recycle reported providing
treatment for the recycle flow.
                              TABLE IV. 12.—TREATMENT OF RECYCLE AT ICR PLANTS 1
ICR recycling plants





Other treatment 	
Number of
plants
226
147
114
14
14
5
Percentage of
recycle plants
100
65
77
10
10
3
  1 Disinfection not counted as treatment because it does not inactivate Cryptosporidium.
  Table IV.13 indicates that 75 percent
of ICR recycle plants return recycle
prior to rapid mix. Fifteen percent
return it prior to sedimentation, and ten
percent of plants return it prior to
filtration. These percentages hold for the
                     subsets of plants serving greater than
                     and less than 100,000 people. The data
                     indicate that introducing recycle prior
                     to rapid mix may be a common practice.
                     EPA believes that introducing recycle
                     flow prior to the point of primary

                     TABLE  IV.13.—RECYCLE RETURN POINT
coagulant addition, is the best recycle
return location because it limits the
possibility residual treatment chemicals
in the recycle flow will disrupt
treatment chemistry.
Point of recycle return



Prior to filtration 	
Number of
plants
1224
169
34
21
percent of
plants
100
75
15
10
  1 Recycle return point could not be determined for two plants.
  The data provides the following
conclusions regarding the recycle
practice of ICR plants: (1) The recycle of
spent filter backwash and other process
streams is a common practice; (2) the
great majority of recycle plants in the
database use filtration and surface water
sources; (3)  a majority of plants in the
database that recycle provide treatment
for recycle flow, and; (4) a large majority
of plants in the database that recycle
(approximately 3 out of 4) recycle prior
to the point of primary coagulant
addition.
                     b. Recycle FAX Survey
                       The AWWA sent a FAX survey
                     (AWWA, 1998) to its membership in
                     June 1998 to gather information on
                     recycle practices. Plants were not
                     targeted based on source water type, the
                     type of treatment process employed, or
                     any other factor. The survey was sent to
                     the broad membership to increase the
                     number of responses. Responses
                     indicating a plant recycled spent filter
                     backwash or other flows were compiled
                     to create a database. The resulting
                     database included  335 plants. The
                     database does not contain information
                     from respondents who reported recycle
was not practiced. Data from some of
the FAX survey respondents also
.populates the ICR database. Plants in
the database are well distributed
geographically and represent a broad
range of plant sizes as measured by
capacity. Figure IV. 11 shows plant
distribution by capacity and Figure
IV. 12 by geographic location. The
following discussion of FAX survey data
is divided into two sections. The first
discusses national recycle practice and
the second discusses options for recycle
disposal in lieu of returning recycle to
the treatment process.
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      Federal Register/Vol. 65,  No. 69/Monday, April 10, 2000/Proposed Rules
                                                                                      19107
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19108
Federal Register/Vol.  65, No. 69/Monday, April 10, 2000/Proposed Rules
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                  Federal Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed  Rules
                                                                    19109
i. Recycle practice

  Data summarized in Table IV. 14 show
that 78 percent of plants in the database
rely on a surface water as their source.
The percentage of plants using source
water influenced by a surface water
(which may contain Cryptosporidium)
could be higher because the data do not
report whether wells were pure ground
water or GWUDI.

 TABLE  IV.14.—SOURCE WATER USED
       BY FAX SURVEY PLANTS
Source water type
Surface Water 	
River 	 	 	
Reservoir 	
Lake 	
Other 	
Well i 	
Percent
of plants
78
27
28
16
7
22
  1 Wells sources not defined as either ground
water or ground water under the direct influ-
ence of surface water.

  Table FV.15 shows that a wide variety
of treatment process types are included
in the data, with conventional filtration
(rapid mix, coagulation, sedimentation,
filtration) representing over half of the
plants submitting data. Upflow
clarification is the second most common
treatment process reported. Ten percent
of plants in the database use direct
filtration. Only four percent of plants do
not use rapid granular filtration.
TABLE IV.15.—TREATMENT TRAINS OF
        FAX SURVEY PLANTS
Treatment process type
Rapid mix, coagulation, filtration ....
Upflow clarifier 	
Softening
Direct filtration 	
Other 	
Percent
of
plants 1
51
21
14
10
4
  196 percent of plant in the database provide
filtration.
  Table IV. 16 indicates that a vast
majority of plants recycle prior to the
point of primary coagulant addition.
Only six percent of plants returned
recycle in the sedimentation basin or
just prior to filtration.

   TABLE IV.16.—RECYCLE RETURN
    POINT OF FAX SURVEY PLANTS
Return point
Prior to point of primary coagulant
addition 	
Pre-sedimentation (e.g., rapid mix)
Sedimentation basin 	
Before filtration

Percent
of plants
83
11
, 4
2

  Table IV.17 shows that the majority of
plants in the database provide some
type of treatment for the recycle flow
prior to its reintroduction to the
treatment process. Approximately 70
percent of plants reported providing
treatment, with sedimentation being
employed by over half of these plants.
Equalization, defined as a treatment
technology by the survey, is practiced
by 20 percent of plants in the database.
Fourteen percent of plants reported
using both sedimentation and
equalization.

 TABLE IV.17.—RECYCLE TREATMENT
       AT FAX SURVEY PLANTS
Treatment type
No treatment 	
Treatment
Sedimentation
Equalization 	
Sedimentation and equalization 	
Lagoon
Others 	
Percent
of plants
30
70
54
20
14
5
- 7
  Table IV.18 summarizes recycle
treatment practice and frequency of
direct recycle based on population
served. The table illustrates that, for
plants supplying data, treatment of
recycle with sedimentation is provided
more frequently as plant service
population deceases. Plants serving
populations of less than 10,000 recycle
directly (27.5 percent) less frequently
than plants serving populations greater
than 100,000 (50 percent). The data
indicate that a majority of small plants
in the database may have installed
equalization or sedimentation treatment
to protect treatment process integrity
from recycle induced hydraulic
disruption. All direct filtration plants in
the FAX survey provide recycle
treatment or equalization.
                         TABLE IV.18.—RECYCLE PRACTICE BASED ON POPULATION SERVED 1

<10,000 	
10000-50000 	
50,000-100000 	
100.000 	
#Plants
43
79
35
65
Equalization
9% (n=4)
10% (n=8)
17% (n=6)
35% m=23)
Sedimentation
67% (n=29)
57% (n=45)
54% (n=19)
23% (n=15)
•
Direct recycle
23% (n=10)
33% (n=26)
29% (n=10)
42% (n=27)
                                                                                  Recycle practice
  1 Based on 222 surface water plants suppling all necessary data to make determination.
  FAX survey data support the
following conclusions regarding the
recycle practice of plants supplying
data: (1) The recycle of spent filter
backwash and other process streams is
a common practice; (2) the majority of
recycle plants use surface water as their
source and are thereby at risk from
Cryptosporidium; (3) a large majority of
plants providing data recycle prior to
the point of primary coagulant addition,
and; (4) a majority of plants supplying
data provide treatment for recycle
waters prior to reintroducing them to
the treatment plant. The FAX survey.
provides an informative snapshot of
national recycle practices due to the
number of recycle plants it includes, the
geographic distribution of respondents,
and the good representation of plants
serving populations of less than 10,000
people.

ii. Options to recycle.

  The FAX survey asked whether
feasible alternatives to recycle are
available (i.e., NPDES surface water
discharge permit, pretreatment  permit
for discharge to POTW) and the
importance of recycle to optimizing
treatment performance and meeting
production requirements. Responses to
these questions is summarized in Table
IV.19.
  Table IV.19 shows that approximately
20 percent of respondents could not
obtain either an NPDES surface water
discharge permit or a pretreatment
permit for discharge to a POTW.
Approximately 90 percent of
respondents stated that recycle flow is
not important to meet typical demand.

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19110
Federal  Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed Rules
Twenty-four percent of all respondents
stated that returning recycle to the
treatment process is important for
                     respondents may have considered not
                     changing current plant operation (e.g.,
                     not changing current recycle practice)
practice is important for the plant to
produce the highest quality finished
water.
optimal operation. "Optimal operation"   an aspect of optimal treatment, rather
was not defined by the survey and
                     than addressing whether recycle
                    TABLE IV. 19.—OPTIONS TO RECYCLE AS REPORTED BY FAX SURVEY PLANTS'"
Question
Able to obtain NPDES surface discharge permit*? 	

Can obtain either an NPDES or a POTW discharge permit'? 	
Is recycle important to meet peak demand*? 	 * 	
Is recycle important to meet typical demand1? 	
Is recycle important to optimal operation*? (All plants in survey) 	


Percent
Yes
41%
(n=131)
43%
(n=137)
60%
(n=192)
14%
(n=44)
9%
(n=28)
24%
(n=75)
13%
(n=3)
Percent
No
37%
(n=120)
42%
(n=136)
19.5%
(n=63)
80%
(n=257)
85%
(n=272)
70%
(n=225)
83%
(n=19)
Percent
Unknown
22%
(n=70)
15%
(n=48)
20.5%
(n=66)
6%
(n=20)
6%
(n=21)
6%
(n=21)
4%
(n=1)
  1 Number of plants varies from question to question due to different response rates.
  2 Optimal operation not defined by survey. May include overall plant operation rather than importance of recycle to producing highest possible
quality finished water.
iii. Conclusions
  The ICR and FAX survey data are
complimentary, as the ICR data supplies
a wealth of data regarding recycle
practices at large capacity plants, while
the FAX Survey provides data on
recycle practices over a range of plant
capacities. Taken together, the two data
sets provide a good picture of current
recycle practice. The data indicate that
recycle is a common practice for plants
sampled. Approximately half of the
respondents providing data return
recycle flow to the treatment process
and 70 percent provide some type of
recycle treatment. Sedimentation and
equalization are the two most
commonly employed treatment
technologies for plants supplying data.
Approximately 80 percent of plants
sampled return recycle prior to the
point of primary coagulant addition.
Examining the recycle practices of
plants in the ICR and FAX survey data
show that small plants (f.e., fewer than
10,000 people served) are more than
twice as likely as  large plants (i.e.,
greater than 100,000 people served) to
provide sedimentation for recycle
treatment (58 versus 26 percent).
  The FAX survey responses show that
approximately half of plants providing
data have an option to recycle return,
whether it be an NPDES surface water
discharge permit or discharge to a
POTW. Eighty-five percent of
respondents stated that recycle flow is
not important to meet peak demand.
Less than a quarter of respondents have
monitored pathogen concentrations in
                     backwash water and fewer than half
                     have any monitoring data to
                     characterize the quality of the backwash
                     water.

                     3. Recycle Provisions for PWSs
                     Employing Rapid Granular Filtration
                     Using Surface Water or Ground Water
                     Under the Direct Influence of Surface
                     Water
                     a. Return Select Recycle Streams Prior
                     to the Point of Primary Coagulant
                     Addition
                     i. Overview and Purpose
                       Today's proposal requires that
                     systems employing rapid granular
                     filtration and using surface water or
                     GWUDI as a source return filter
                     backwash, thickener supernatant, and
                     liquids from dewatering processes to the
                     primary treatment process prior to the
                     point of primary coagulant addition.
                     The goal of this provision is to protect
                     the integrity of chemical treatment and
                     ensure these recycle streams are passed
                     through as many physical removal
                     processes as possible to provide
                     maximum opportunity for removal of
                     Cryptosporidium oocysts from the
                     recycle flow. Since Cryptosporidium is
                     resistant to standard disinfection
                     practice, it is important that chemical
                     treatment be optimized to protect
                     treatment plant efficiency and that all
                     available physical removal processes be
                     employed to remove it.
                       Today's proposal requires these flows
                     be returned prior to the point of primary
                     coagulant addition because these
                     streams are either of sufficient volume
to cause hydraulic disruption within the
treatment process when recycled and/or
are likely to contain Cryptosporidium
oocysts. Minor recycle streams, such as
lab sample lines, pump packing water,
and infrequent process overflows are
not likely to threaten plants' hydraulic
stability or contain appreciable numbers
of oocysts.
  Treatment plant types that need to
return recycle to a location other .than
prior to the point of primary coagulant
addition to maintain optimal treatment
performance (optimal performance as
indicated by finished water or intra-
plant turbidity levels), plants that are
designed to employ recycle flow as an
intrinsic component of their operations,
plants with very low influent turbidity
levels that may need alternative recycle
locations to obtain satisfactory
suspended solids removal, or other
types of plants constrained by unique
treatment considerations, may apply to
the State to recycle at an alternative
location under today's proposal. Once
approved by the State, plants may
recycle to the specified location.

ii. Data
  Data from the ICR and FAX Survey
indicate that 75 and 78 percent of
plants, respectively, return recycle prior
to the point of primary coagulant
addition. The "point of primary
coagulant addition" was defined in both
analyses as the return of recycle prior to
the rapid mix unit. The FAX Survey
data indicate that 77 percent of plants
serving under 10,000 people recycle
prior to the point of primary coagulant

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                   Federal Register/Vol. 65, No. 69/Monday,  April 10, 2000/Proposed Rules
                                                                      19111
addition. It also showed that 78 percent
percent of all plants in the database
return recycle there, which suggests that
plants serving smaller populations may
return recycle prior to the point of
primary coagulant addition as
frequently as plants serving larger
populations. Other common recycle
return locations are the rapid mix unit,
between rapid mix and clarification, or
into the clarification unit itself.
  The Agency does not believe filter
backwash, thickeners supernatant, or
liquids from dewatering processes
should be recycled at the point of
primary coagulant addition or after it for
three reasons:
  (l)  Addition of these recycle streams,
which can contain residual coagulant
and other treatment chemicals, after the
location of primary coagulant addition,
may render the chemical dose applied
less effective, potentially harming the
efficiency of subsequent treatment
processes;
  (2)  Introduction  of recycle into the
flocculation unit or clarification unit
may create hydraulic currents that
exacerbate or create short circuiting,
and;
  (3)  Recycle introduced into the
clarification process may not experience
sufficient residence time for adequate
solids removal to occur.
  The Agency is concerned that plants
may not adjust chemical dosage during
recycle events to account for:  (1) The
presence of a potentially significant
amount of residual treatment chemical
in recycle flow and changes in recycle
flow quality, and; (2) potentially large
fluctuations in plant influent flow
during recycle events. EPA is concerned
that changes in influent water quality
and flow are not monitored on an
instantaneous basis during recycle
events. Since the chemistry of the
recycle flow and source water may
differ significantly, it is important
plants mix source and recycle water to
establish a uniform chemistry prior to
applying treatment chemical so the dose
is appropriate for the mixture.
Additionally, wide fluctuation in plant
influent flow during recycle events may
cause chemical over-or under-dosing,
which can lower overall oocyst removal
efficiency. In an article concerning
optimization of filtration performance,
Lytle  and Fox (1996) state, "The
capability to instantaneously monitor
treatment processes and rapidly and
effectively respond to raw and filter
effluent quality changes are important
factors in consistently producing low
turbidity water." Logdson (1987) further
states, "For a plant to be operated
properly, the total flow rate has to be
known on an instantaneous basis or by
volumetric measurement." EPA believes
it is important plants diligently monitor
the appropriateness of chemical dosing
at all times, but particularly during
recycle events, and strive for real-time
chemical dose and influent flow
management to optimize plant oocyst
removal.
  Pilot-scale research conducted by
Patania et al. (1995) to examine the
optimization of filtration found that
chemical pretreatment was the most
important variable determining oocyst
removal by filtration. Edzwald and
Kelley (1998) performed pilot-scale
work to determine the ability of
sedimentation, DAF, and filtration to
remove Cryptosporidium and found that
coagulation is critical to effective
Cryptosporidium control by clarification
and filtration. Bellamy et al. (1993)
stated that the most important factor in
plant performance is the use of optimal
chemical dosages. Coagulation was
recognized as the single most important
step in the process of water clarification
by Conley (1965). Ten pilot scale runs
performed by Dugan et al.  (1999)
showed that coagulation has a large
influence on the log removal of
Cryptosporidium achieved by
sedimentation. The importance of
proper coagulation to filter performance
was noted by Robeck et al. (1964) in
pilot and full-scale work that showed
proper coagulation is more important to
the production of safe water than the
filtration rate used. Results of direct
filtration pilot studies, summarized by
Trussell et al. (1980), showed that
"effective coagulant is absolutely
necessary if good effluent qualities are
to be consistently produced."
  Given the critical role proper
chemical dosing plays in maintaining
effective  clarification and filtration
processes, the Agency believes it is
prudent and necessary to minimize the
possibility recycle of spent filter
backwash, thickener supernatant, and
dewatering liquids will render chemical
dosages applied  during recycle events
inaccurate, due to the presence of
residual chemical or variations in
influent flow, by requiring they be
returned  prior to the point of primary^
coagulant addition.
  Finally, a fundamental tenet of water
treatment is multiple treatment barriers
should be provided to prevent microbial
pathogens from entering finished water.
To achieve this, conventional plants
rely on coagulation, flocculation,
clarification, and filtration as preventive
microbial barriers. The Agency believes
it is important that recycle waters be
passed through each of these treatment
processes to maximize the  probability
disinfection resistant oocysts will be
removed in the plant and not enter the
finished water supply.

iii. Proposed Requirements
  Today's proposal requires that rapid
granular filtration plants using surface
water or GWUDI as a source return filter
backwash, thickener supernatant, and
liquids from dewatering processes prior
to the point of primary coagulant
addition. Plants that require an
alternative recycle return location to  .
maintain optimal finished water quality
(as indicated by finished water or intra-
plant turbidity levels), plants that are
designed to employ recycle flow as an
intrinsic component of the treatment
process, or plants with unique treatment
requirements or processes may apply to
the State to return recycle flows to an
alternative location. Plants may utilize
this alternative location once granted by
the State. EPA will develop detailed
guidance and make it  available to States
and PWSs.
  Softening systems may recycle
process solids, but not spent filter
backwash, thickener supernatant, or
liquids from dewatering processes, at
the point of lime addition immediately
preceding the softening process to
improve treatment efficiency. Literature
establishes that return of process solids
to point of lime addition decreases
production of nuclei, increases the rate
of crystallization, and increases crystal
size, all of which enhance settling and
process integrity (Randtke, 1999;
Snoeyink and Jenkins, 1980). Contact
clarification systems may recycle
process solids, but not spent filter
backwash, thickener supernatant, or
liquids from dewatering processes,
directly into the contactor to improve
treatment efficiency.
iv. Request for Comments
  EPA requests comment on the
proposed requirements. The Agency
also requests comment on the following
aspects of this provision:
  (1) What regulatory  options are
available to ensure direct recycle plants
practice real-time chemical dose and
influent flow management? Should
flow-paced coagulant feed be required at
direct recycle plants to minimize
potential harmful impacts of recycle?
What regulatory requirements may be
applicable to ensure the integrity of the
coagulation process?
  (2) What treatment processes or
treatment configurations may need an
alternative recycle location to maintain
optimal treatment?
  (3) What alternative recycle locations
are appropriate for such treatment
configurations and what location may
be inappropriate?

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Federal Register/Vol.  65, No.  69/Monday, April 10, 2000/Proposed Rules
  (4) Are there other reasons, beyond
maintaining optimal treatment
efficiency, to justify granting alternate
recycle locations to plants? What are
they?
  (5) What criteria, operating practices,
or other parameters should be evaluated
to determine whether an alternative
recycle return location should be
granted?
  (6) Does recycling at the point of
primary coagulant addition, instead of
prior to it, provide assurance that an
appropriate dose of treatment chemicals
will be consistently applied during
recycle events? Is it necessary to mix the
recycle and raw water prior to chemical
addition to ensure a consistent water
chemistry for chemical dosing?
  (7) Are there circumstances where it
would be appropriate to allow systems
to recycle at the point of primary
coagulant addition?

b. Recycle Requirements for Systems
Practicing Direct Recycle and Meeting
Specific Criteria
i. Overview and Purpose
  Today's proposal requires that self
assessments be performed at
conventional filtration plants meeting
all of the following criteria and the
results of the self assessment reported to
the State. The criteria are:
  (1) Use of surface water or GWUDI as
a source;
  (2) Employ of 20 or fewer filters to
meet production requirements  during
the highest production month in the 12
month period prior to LTlFBR's
compliance date, and;
  (3) Recycle spent filter backwash or
thickener supernatant directly to the
treatment process (i.e., recycle  flow is
returned within the treatment process of
a PWS without first passing the recycle
flow through a treatment process
designed to remove solids, a raw water
storage reservoir, or some other
structure with a volume equal to or
greater than the volume of spent filter
                     backwash water produced by one filter
                     backwash event.)
                       The goal of the self assessment is to
                     identify those direct recycle plants that
                     exceed their State approved operating
                     capacity, on an instantaneous basis,
                     during recycle events. Plants are
                     required to submit a monitoring plan to
                     the State prior to conducting the month
                     long self assessment monitoring. Results
                     of self assessment monitoring must be
                     reported to the State. The State is
                     required to determine, by reviewing the
                     self assessment, whether the plant's
                     current recycle practice should be
                     modified to protect plant performance
                     and provide an additional measure of
                     public health protection. The State is
                     required to report its determination for
                     each plant performing a self assessment
                     to EPA and briefly summarize the
                     reason(s) supporting  each
                     determination.
                       EPA selected the three
                     aforementioned criteria to identify
                     plants required to perform a self
                     assessment for the following reasons.
                     First, surface or GWUDI source waters
                     may contain Cryptosporidium. Second,
                     the hydraulic impact of recycle to plants
                     typically employing more than 20 filters
                     to meet production requirements should
                     be dampened because plant influent
                     flow is of significantly greater
                     magnitude than the flow produced by a
                     backwash event. Third, plants that
                     practice direct recycle of filter backwash
                     and/or thickener supernatant may
                     exceed their operating capacity during
                     recycle events due to the large volume
                     of these streams.
                     ii. Data
                       Plants that recycle  filter backwash
                     and thickener supernatant, directly,
                     without recycle flow equalization or
                     treatment, may exceed their operating
                     capacity during recycle events. Table
                     IV.20 illustrates the magnitude by
                     which direct recycle plants may exceed
                     their operating capacity during recycle
                     events. For purposes  of the table,
operating capacity is assumed to be
either plant design flow or average flow
(see example below). The values in the
table are conservative, as they are likely
to over predict the factor by which
direct recycle plants will exceed
operating capacity during recycle
events. This conservatism is due to the
assumed filter backwash rate of 15 gpm/
ft2 and the assumed backwash duration
of 15 minutes, the minimum backwash
rate and duration recommended by the
Great Lakes-Upper Mississippi River
Board of State and Provincial Public
Health and Environmental Managers
(1997). Design and average flow values
assumed for plant operating capacity
were developed from equations
presented in EPA's baseline handbook
(1999g). For purposes of this example,
plant design and average flow are
assumed to equal State approved
operating capacity to illustrate the
potential for plants to exceed operating
capacity during recycle events. Relevant
equations and example calculations  are
shown below.
Example
  (1) Design to average ratios:
design flow < .25 mgd; ratio design flow :
   average flow = 3.2:1
design flow > .25 mgd to 1 mgd; ratio design
   flow : average flow = 2.8:1
design flow > 1 mgd to 10 mgd; ration design
   flow : average flow = 2.4:1
design flow > 10 mgd; ratio design flow :
   average flow = 2.0:1
  (2) Maximum filter size: 700 sq./ft2 (EPA,
1998a)
  (3) Backwash volume calculation:
Filter area (ft2) x 15 gpm/ft2 x 15 minutes =
   volume of one backwash
  (4) Design and average capacity exceedence
factors:
(Backwash flow -t- design (or average) flow)
-s- design flow = exceedence factor
  (5) Percent Influent that is recycle:
Backwash flow •*• (Backwash flow + design
(or average flow)) = percent of influent that
is backwash
  (6) Design flow = State approved operating
flow
                                     TABLE IV.20.—IMPACT OF DIRECT RECYCLE
Design
flow
(MGD)
.033
.669
2.02
8.8
14.5
42.44
56.23
Number of
filters
2
4
6
8
10
18
24
Area of
one filter
(sq. ft)
5
50
100
320
425
700
700
Volume of
one back-
wash
(gallons)
1,125
11,250
22,500
72,000
95,625
157,500
157,500
Backwash
return flow
(15 minute
return;
gpm)
75
750
1,500
4,800
6,375
10,500
10,500
Design
flow
(gpm)
23
465
1,403
6,111
10,069
29,472
39,048
Average
flow
(gpm)
7
166
584
2,546
5,135
14,736
19,524
Factor de-
sign flow
is exceed-
ed by dur-
ing recycle
(at design
flow)
4.3
2.6
2.1
1.8
1.6
1.4
1.3
Percent in-
fluent that
is recycle
(at design
flow)
(percent)
77
62
52
44
39
26
21
Factor de-
sign flow
is exceed-
ed by dur-
ing recycle
(at aver-
age flow)
3.6
2.0
1.5
1.2
1.1
.86
.77
Percent in-
fluent that
is recycle
(at aver-
age flow)
(percent)
91
82
72
65
55
42
35

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                                                                     19113
  The purpose of Table IV. 20 is to
illustrate the impact direct recycle can
have on plant hydraulic loading and the
factor by which plant operating capacity
can be exceeded during recycle events.
As shown in Table IV.20, a plant with
two filters would process influent at
over three times its operating capacity
during a recycle event. Even if the plant
reduced or eliminated its raw water
influent flow for the duration of the
event, the remaining filter would be
subject to a loading rate that exceeds its
operating capacity, which could harm
finished water quality.
  The amount of sedimentation basin or
clarification process storage available
during recycle events will have an
impact on the hydraulic loading to the
filters and the performance of the
sedimentation or clarification process.
The actual increase to filter loading
rates may be less than predicted in
Table IV.20 due to site-specific
conditions. However, the potential for
direct recycle plants to exceed operating
capacity is cause for concern because
oocyst removal can be compromised.
The Agency believes 20 filters is an
appropriate number for specifying
which plants are required to perform a
self assessment due to the results in
Table IV.20 and the above
considerations.
  The importance of maintaining proper
plant hydraulics has been
acknowledged, notably by Logdson
(1987) who wrote, "Both the quantity
and quality of filtered water can be
affected by plant hydraulics. Maximum
hydraulic capacity is an obvious
limitation. The adverse influences of
rate of flow and flow patterns on water
quality may not be so obvious, but they
can be important." Fulton (1987)
recognized that short circuiting can
diminish the performance of settling
basins, cause overloading of filters, and
increase breakthrough of turbidity.
Other publications (Cleasby, 1990)
recognize that settled water quality
deteriorates when the surface loading
rate of sedimentation basins is
increased. Direct recycle practice can
give rise to short circuiting, cause plant
operating capacity to be exceeded, and
increase surface loading rates, all of
which can be detrimental to
Cryptosporidium removal.
  Direct recycle practice can abruptly
increase filter loading rates, which has
been shown to lower filter performance.
Cleasby etal. (1963) performed
experimental runs with three pilot plant
filters by increasing the filtration rate
ten, twenty-five, and fifty-percent over
various time periods and monitoring the
passage of a target material during the
rate increase. Conclusions drawn from
the experiments were:
  (l) Disturbance in filtration rate can
cause filters to pass previously
deposited material and the amount of
material passed is dependent on the
magnitude of the  rate disturbance;
  (2) More rapid disturbances cause
more material to be flushed through the
filter;
  (3) The amount of material flushed
through the filter  is independent, or
very nearly independent of
disturbance's duration, and;
  (4) The amount of material flushed
through the filter  following a
disturbance is dependent on the type of
material being filtered.
  Pilot scale work was recently
performed by Glasgow and Wheatley
(1998) to investigate whether surges
affect filtrate quality. Effluent turbidity
and headloss within the filter media
were monitored for two pilot filter
columns that were surged at different
magnitudes. The results were compared
to control runs through the same pilot
columns to determine the effect of the
surge. Results indicated that surging
may significantly affect full scale filter
performance. Additional work is needed
to confirm these results.
  Recent pilot scale work by McTigue et
al. (1998) examined the impact of
doubling the filter loading
instantaneously and gradually (over an
80 minute period) on pilot filters that
had been in operation for a period of
time or were "dirty." The experiments
showed that Cryptosporidium removal
achieved by the filters was lowered by
changes in filtration rate regardless of
whether loading rate was increased
instantaneously or gradually. In the
experiment, filter loading rates of 2
gpm/ft2 and 4 gpm/ft2 were doubled in
six  separate test runs to determine
whether oocysts removal was affected.
Results  showed that log removal of
oocysts  was reduced by approximately
1.5  to 2.0 logs for  when filter loading
rates of  2 gpm/ft2  and 4 gpm/ft2 were
either instantaneously and gradually
doubled. The report states, "These data
clearly demonstrate that any change in
filter loading rate  on a filter that is dirty
presents a risk for breakthrough of
Giardia  and Cryptosporidium to the
finished water, should these organisms
be present in the filter." Effluent
turbidity values remained low during
increases in filter  loading rates but
particle count concentrations
immediately increased with increases in
loading  rate. This may indicate that
turbidity is not a good indicator of
oocyst passage by dirty filters during
filtration rate increases.
  Results of three other pilot runs from
the study showed that log removal of
oocysts did not change when the
influent oocyst concentration varied and
all other treatment conditions were held
constant. A four log removal of oocysts
was obtained for all three runs despite
influent oocyst concentrations of 4.610/
L, 688/L, and 26/L. The report states,
"This finding indicates that the risk for
passage of large numbers of cysts to the
finished water is greater when a water
treatment plant receives a highly
concentrated slug of cysts at its intake."
The Agency believes this is an
interesting conclusion, even though it is
based on a limited number of pilot runs.
If further pilot and full-scale work
verifies this finding, it indicates that log
removal of oocysts does not increase as
more oocysts are loaded to plant.
Recycle of flows containing oocysts
would therefore increase the number of
oocysts present in finished water,
relative to the number of oocysts that
would occur were recycle not practiced,
because plant treatment efficiency
would not increase to remove the
additional oocysts returned by recycle.
  In summary, the Agency is concerned
that direct recycle of spent filter
backwash, thickener supernatant,  and
liquids from dewatering process may
increase the risk of oocyst occurrence in
finished water for the following reasons:
  (1) Sampling has established that
oocysts occur in finished water supplies
(see Table II.6 of this preamble);
  (2) Data show that oocysts occur in
recycle streams;
  (3) Literature indicates that
hydraulically overloading the
sedimentation process, as may happen
during direct recycle events, can harm
sedimentation performance;
  (4) Literature indicates increasing or
abruptly changing filtration rates can
lead to more material passing through
filters, and;
  (5) Recent pilot scale work by
McTigue et al. (1998) and Glasgow and
Wheatley (1998) indicates that filter
performance can be harmed by surges
and changes to filtration rate.
  The Agency encourages the States to
closely examine recycle self assessments
performed by direct recycle plants to
determine whether direct recycle poses
an unacceptable risk to finished water
quality and public health and needs to
be modified due to the considerations
cited above.
  Finally, EPA realizes that State
programs may use different
methodologies to set plant operating
capacity. States may also apply safety
factors of different magnitudes when
determining operating capacity. The
Agency does not believe it is

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 appropriate to erode any safety factor or
 margin of safety States provide when
 setting operating capacity. Safety factors
 are provided for a reason: to provide a
 margin of safety to public health
 protection efforts. The integrity and
 magnitude of a safety factor should be
 maintained, as it is in and of itself
 integral to adequate public health
 protection. The fact a safety factor is
 applied when plant operating capacity
 is set is not a justification, a priori, for
 allowing plants to operate above said
 operating capacity during recycle
 events.
   EPA also acknowledges that States
 may use different methodologies to set
 plant operating capacity. The Agency is
 confident that the State programs, its
 partners in public health protection, set
 plant capacity to provide necessary
 level of public health protection. The
 fact that some State programs may set
 plant operating capacities with different
 methodologies likely reflects
 geographical conditions and public
 expectations unique  to certain States
 and sections of the country. EPA
 believes methodologies employed by the
 States results in establishment of
 operating capacities necessary to protect
 public health, meet regulatory
 requirements, and satisfy unique
 treatment needs and  considerations
 where they exist.
 iii. Proposed Requirements
   Self assessments must be performed at
 plants meeting all of the following
 criteria and the results of the self
 assessment reported to the State:
   (1) Use surface water or GWUDI as a
 source and employ conventional rapid
 granular filtration treatment;
   (2) Employ of 20 or fewer filters to
 meet production requirements  during
 the highest production month in the 12
 month period prior to LTlFBR's
 compliance date, and;
   (3 j Recycle spent filter backwash or
 thickener supernatant directly to the
 treatment process [i.e., recycle  flow is
 returned within the treatment process of
 a PWS without first passing the recycle
 flow through a treatment process
 designed to remove solids, a raw water
 storage reservoir, or some other
 structure with a volume equal to or
 greater than the volume of spent filter
backwash water produced by one filter
backwash event).
  Systems are required to develop and
 submit a recycle self assessment
 monitoring plan to the State no later
than three months after the rule's
compliance date for each plant the
requirements are applicable to. At a
minimum, the monitoring plan must
identify the month during which
                     monitoring will be conducted, contain a
                     schematic identifying the location of
                     raw and recycle flow monitoring
                     devices, describe the type of flow
                     monitoring devices to be used, and
                     describe how data from the raw and
                     recycle flow monitoring devices will be
                     simultaneously retrieved and recorded.
                       The self assessment of recycle
                     practices shall consist of the following
                     five steps:
                       (1) From historical records, identify
                     the month in the calendar year
                     preceding LTlFBR's effective date with
                     the highest water production.
                       (2} Perform the monitoring described
                     below in the twelve month period
                     following submission of the monitoring
                     plan to the State.
                       (3) For each day of the month
                     identified in (1), separately monitor
                     source water influent flow and recycle
                     flow before their confluence during one
                     filter backwash recycle event per day,  at
                     three minute intervals during the
                     duration of the event. Monitoring  must
                     be performed between 7:00 a.m. and
                     8:00 p.m. Systems that do not have a
                     filter backwash recycle event every day
                     between 7:00 am and 8:00 p.m. must
                     monitor one filter backwash recycle
                     event per day, any three days of the
                     •week, for each week during the month
                     of monitoring, between 7:00 a.m. and
                     8:00 p.m. Record the time filter
                     backwash was initiated, the influent and
                     recycle flow at three minute intervals
                     during the duration of the event, and the'
                     time the filter backwash recycle event
                     ended. Record the number of filters in
                     use when the filter backwash recycle
                     event is monitored.
                       (4) Calculate the arithmetic average of
                     all influent and recycle flow values
                     taken at three minute intervals in (3).
                     Sum the arithmetic average calculated
                     for raw water influent and recycle flows.
                     Record this value and the date the
                     monitoring was performed. This value is
                     referred to as event flow.
                       (5) After monitoring is complete,
                     order the event flow values in
                     increasing order, from lowest to highest,
                     and identify the monitoring events in
                     which plant operating capacity is
                     exceeded.
                       Systems are required to submit a self
                     assessment report to the State within
                     one month of completing the self
                     assessment monitoring. At a minimum,
                     the report must provide the following
                     information:
                       (1) All source and recycle flow
                     measurements taken and the dates they
                     were taken. For all events monitored,
                     report the times the filter backwash
                     recycle event was initiated, the flow
                     measurements taken at three minute
                     intervals, and the time the filter
 backwash recycle event ended. Report
 the number of filters in use when the
 backwash recycle event is monitored.
   (2) All data and calculations
 performed to determine whether the
 plant exceeded its operating capacity.
 Report the number of event flows that
 exceed State approved operating
 capacity.
   (3) A plant schematic showing the
 origin of all recycle flows, the hydraulic
 conveyance used to transport them, and
 their final destination in the plant.
   (4) A list of all the recycle flows and
 the frequency at which they are
 returned to the plant.
   (5) Average and maximum backwash
 flow through the filters and the average
 and maximum duration of backwash
 events in minutes, for each monitoring
 event, and;
   (6) Typical filter run length, number
 of filters typically employed, and a
 written summary of how filter run
 length is determined (preset run time,
 headloss, turbidity level).
   EPA is proposing that the State review
 all self assessments  submitted by PWSs
 and report to the Agency the below
 information as it applies to individual
 plants:
   (1) A finding that modifications to
 recycle practice are necessary, followed
 by a brief description of the required
 change and a summary of the reason(s)
 the change is required, or;
   (2) A finding that changes to recycle
 practice are not necessary and a brief
 description of the reason(s) this
 determination was made.
   The Agency also considered requiring
 all recycle plants without existing
 recycle flow equalization or treatment to
 install recycle flow equalization. As
 summarized in Table IV.21, several
 recommendations for recycle
 equalization and treatment have been
 provided. However, these
 recommendations are based on
 theoretical calculations and/or  limited
 pilot-scale data that has not been
 verified by full-scale plant performance
 data. The Agency currently believes
 insufficient data is available to
 determine whether recycle flow
equalization is necessary to protect
 finished water quality, and, if it is, the
level of equalization required to provide
protection to finished water supplies for
 a wide variety of source water qualities,
treatment process types, and levels of
treatment effectiveness. The Agency
does not believe it is appropriate at this
time to propose a national recycle flow
equalization requirement for the
following reasons:
  (l) Data on the occurrence of oocysts
in recycle  streams, and  their impact to

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                                                                     19115
finished water quality upon recycle, is
very limited;
  (2) Data that establishes the
magnitude of hydraulic disruption
caused by direct recycle events for a
variety of plant types, designs, and
operational practices has not been
identified; without this data, it is not
possible to quantify how much
treatment efficiency is reduced by the
hydraulic disruption and the number of
oocysts in the recycle flow that will
enter the finished water due to the
disruption. Without this information, it
is not possible to specify the level of
equalization necessary to control
hydraulic disruption for a variety of
plant configurations and operational
practices with any degree of certainty
and cost effectiveness, and;
  (3) A uniform, national equalization
standard may not be appropriate
because it would not allow
consideration of site-specific factors
such as plant treatment efficiency,
loading capacity of clarification and
filtration units, source water quality,
and other site-specific factors that
influence the level of equalization a
plant may need to control recycle event
induced hydraulic disruption.
  EPA believes some plants can realize
substantial benefit by installing recycle
flow equalization and will review data
to determine the need for an
equalization requirement when it
becomes available. The Agency requests
that commenters submit the following
pilot or full-scale data to assist its effort
to conduct a thorough analysis of
equalization based upon the best
available science:
  (1) Data on the magnitude of
hydraulic disruption caused by recycle
events and its affect on finished water
turbidity and particle count levels;
  (2) Data that correlate hydraulic
disruption to increased oocyst
concentration in finished water, and;
  (3) Any other data commenters
believe that may be appropriate to
analyze the need for equalization, and;
  (4) Whether the regulation should
require States to specify  modifications
to recycle practice, for all plants that
exceed operating capacity during
monitoring, to ensure said plants'
remain below their State approved
operating capacity during recycle
events.
                             TABLE IV.21—RECOMMENDED EQUALIZATION PERCENTAGES
Source of recommendation •
Recommended Standards for Water Works Great Lakes Upper Mississippi
River Board of State and Provincial Public Health and Environmental Man-
agers. 1997. Albany: Health Education Services.
for Water Research Limited, United Kingdom (1994).
Recycle Stream Effects on Water Treatment. Comwell, D., and R. Lee. 1993.
Denver. AWWARF.
Equalization
Percentage
10% 	
10% 	
Use equalized,
continuous recy-
cle.
Is recycle treatment recommended?
No.
Yes. Turbidity less than 5.0 NTU or re-
sidual of 10mg/L suspended solids in
treated recycle flow.
Use proper waste stream treatment
prior to recycle.
  «See the reference list at the end of the preamble for complete citations.
  Finally, the Agency considered
requiring conventional filtration plants
that recycle within the treatment
process to provide sedimentation or
more advanced recycle treatment and
concluded a national treatment
requirement is inappropriate at this time
due data deficiencies. The Agency
believes the following data is necessary
to determine whether recycle flow
treatment is necessary to protect public
health and the requisite level of
treatment:
  (1)  Significant amounts of additional
data on the occurrence of oocysts for a
complete range of recycle streams
generated by a wide variety of source
water qualities, treatment plant types,
plant operational and recycle practices,
and plant treatment efficiencies;
  (2)  Data that correlates recycle stream
oocyst occurrence to finished water
occurrence;
  (3)  Additional data on the ability of
full-scale sedimentation basins to
remove oocysts during normal operation
and during recycle events. The Agency
has identified only three full-scale
studies, States eta/. (1995), Baudin and
Lame (1998), and Kelly et al (1995),
that allow quantification of oocyst
removal by sedimentation basins. Pilot
scale work, such as Edzwald and Kelley
(1998) and Dugan et al. (1999) is also
available, but the number of studies is
not extensive. The removal achieved by
sedimentation and other clarification
processes is critical for determining the
number of oocysts loaded to the filters,
the likely concentration of oocysts in
various recycle streams, and the impact
recycle may have on intra-plant oocyst
concentrations. Good oocyst removal in
the clarification process will remove a
large percentage of oocysts  from recycle
and source water flows before they
reach the filters. The amount of removal
provided by primary clarification
therefore has a large influence on the
level of recycle flow treatment that may
be needed to mitigate risk to finished
water quality. Given that data on oocyst
removal  by sedimentation and other
clarification processes is very limited,
the Agency does not believe it is
possible to assess the need  for recycle
treatment and specify a minimum
treatment level that is meaningful for a
wide variety of plant types  and recycle
practices;
  (4) Data regarding the ability of DAF
and other clarification processes to
remove oocysts from recycle flow is
very limited. This data is important,
because the Agency anticipates plants
may respond to any recycle treatment
requirement by using DAF to treat
recycle flow because of the advantages
it provides relative to sedimentation.
However, EPA has only identified four
studies, Hall et al. (1995), Plummer et
al. (1995), Edzwald and Kelley (1998),
and Alvarez et al. (1999), that
determined the ability of DAF to remove
oocysts from source water.. One study,
by Gmbb et al. (1997), addresses the
ability of DAF to treat filter backwash
waters has been identified, but sampling
for oocyst removal was not performed,
although turbidity and color removal
were monitored and good results
obtained. Additional data is needed to
characterize the ability of DAF to
remove oocysts from recycle flow before
it can be used to meet any recycle
treatment requirement;
  (5) Full-scale data on the ability of
sedimentation and other clarification
processes to remove oocysts from
recycle streams before they are returned
to the plant is very limited. EPA has
identified two studies, one by Cornwell
and Lee  (1993) and a study by Karanis
et al. (1998) that provide data regarding

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Federal Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed Rules
 sedimentation's ability to remove
 oocysts from recycle flows. Additional
 information is needed to establish lower
 and upper bounds on the oocyst
 removal sedimentation can achieve;
 without this data, it is difficult to
 specify a feasible level of oocyst
 removal in a recycle flow treatment
 requirement;
   [6) Microfiltration and ultrafiltration
 membranes appear to be very reliable at
 removing Cryptosporidium from source
 waters Qacangelo et al.,  1995). However,
 the Agency has identified limited data
 regarding the ability of membranes to
 effectively treat recycle flow, and
 treatment of backwash with membranes
 may not be appropriate at all locations
 (Thompson et al., 1995) due to
 incompatibility between membrane
 filter material and residual treatment
 chemical(s) in the backwash water.
 Additional information regarding the
 ability of microfiltration and
 ultrafiltration membranes to treat
 recycle flow is necessary to
 comprehensively evaluate their
 applicability, and;
   (7) EPA is not aware of a surrogate,
 including turbidity, particle counts, or
 any other common and easy to measure
 parameter, that can serve as an indicator
 of the log removal of Cryptosporidium
 recycle flow treatment units achieve.
 The Agency does not believe it is
 economically or technically feasible to
 directly monitor oocyst removal by
 treatment units. Without an accurate,
 easy to measure surrogate for
 Cryptosporidium removal, the Agency
 does not believe it is possible to
 ascertain the level of treatment recycle
 flow treatment units achieve during
 routine operations.
  Given the above limiting factors, the
 Agency does not believe it is prudent to
 establish a national recycle flow
 treatment requirement until additional
 data becomes available. EPA requests
 the following data be submitte'd:
  (1) Data regarding intra-plant and
 recycle stream occurrence of oocysts;
  (2) Information on the ability of
 individual treatment units of the
 primary treatment train to remove
 oocysts during normal, hydraulically
 challenged, and suboptimal chemical
 dose operations;
  (3) Data on the ability  of
 sedimentation and other clarification
 processes to remove oocysts from a wide
range of recycle streams;
  (4) Data on the compatibility of
 specific ultrafiltration and
microfiltration membrane materials
with residual chemicals that occur in
recycle streams and data regarding the
performance of these membrane
materials at full and pilot scale, and;
                       (5) Information on potential
                     surrogates that can be easily measured
                     and can accurately establish the log
                     removal of oocysts removed by recycle
                     flow treatment processes.

                     iv. Request for Comments
                       EPA requests comment on the
                     proposed requirements. The Agency
                     also requests comment on the following:
                       (1) What other parameters could be
                     monitored or what otiier overall
                     monitoring schemes could be employed
                     to assess whether a plant is exceeding
                     its operating capacity?
                       (2) What data should the plant report
                     to the State as part of its self assessment,
                     beyond the monitoring data and other
                     information listed above?
                       (3) Is monitoring during the highest
                     flow month appropriate? Is monitoring
                     during additional months necessary? Is
                     daily monitoring necessary or would
                     less frequent monitoring during the
                     month be sufficient?
                       (4) Should systems be required to
                     monitor and report turbidity
                     measurements from a representative
                     filter taken immediately preceding and
                     after recycle events monitored during
                     the self assessment to help characterize
                     the impact of recycle on plant
                     performance?
                       (5) Is limiting the self assessment to
                     plants with 20 or less filters
                     appropriate? Should the number of
                     filters be less or greater than 20? What
                     is the appropriate number of filters?
                      (6) Should systems be required to
                     monitor sedimentation overflow rates or
                     clarification loading rates while the
                     recycle flow monitoring is performed?
                      (7) EPA requests comment on criteria
                     that may identify recycle plants that
                     could receive substantial benefit from
                     implementing recycle equalization or
                     treatment as a standard practice.
                      (8) What type and amount of data is
                     required to determine whether recycle
                     flow equalization would provide a
                     benefit to  finished water quality? What
                     methodology could be used to
                     determine an appropriate recycle flow
                     equalization percentage, and how
                     relevant are turbidity and particle
                     counts, at various locations in a plant,
                     to assessing an appropriate equalization
                     percentage for a single plant or a plant
                     type?

                     d. Requirements for Direct Filtration
                     Plants that Recycle Using Surface  Water
                     or GWUDI

                     i. Overview and Purpose
                      Today's proposal requires direct
                     filtration plants that recycle to report to
                    the State whether flow equalization or
                    treatment is provided for recycle flow
 prior to its return to the treatment
 process. The purpose of today's
 proposed requirement is to assess
 whether the existing recycle practice of
 direct filtration plants addresses
 potential risks. The Agency believes that
 direct filtration plants need to remove
 oocysts from recycle flow prior to
 reintroducing it to the treatment
 process.

 ii. Data

  Twenty-three direct filtration plants
 that used surface water responded to the
 FAX Survey (AWWA, 1998). In the FAX
 survey, plants could report whether
 they provide recycle flow equalization,
 sedimentation, or some  other type of
 treatment. Of the respondents, 21
 reported providing treatment for the
 recycle flow and two plants reported
 providing only equalization. In the ICR
 database, there were 23  direct filtration
 plants and fourteen of them recycled to
 the treatment process. All fourteen
 plants provide recycle treatment. It is
 not possible to determine the level of
 oocyst removal FAX survey and ICR
 plants achieve with available data.
  The treatment train of a direct
 filtration plant does not have a
 clarification process to remove
 Cryptosporidium before they reach the
 filters; all oocyst removal is achieved by
 the filters. If recycle flow treatment is
 not provided, all of the oocysts captured
 in the filters will be returned to the
 treatment process in the recycle flow.
 Because a primary clarification process
 is not present to remove recycled
 oocysts, they are caught in a closed
 "loop" from which the only exit  is
 passage through the filters into the
 distribution system. The Agency
 believes direct filtration plants should
 provide solids removal treatment for
 recycle flows to limit the number of
 oocysts returned to the treatment plant.

 iii. Proposed Requirements

  EPA is proposing that  PWSs using
 direct filtration that recycle to the
 treatment process and utilize surface
 water or GWUDI as a source report data
 to the State that describes their current
 recycle practice. Plants should report
 the following information to the State:
  (l) Whether recycle flow treatment or
 equalization is in place;
  (2) The type of treatment provided for
the recycle flow;
  (3) If equalization, sedimentation, or
 some type of clarification process is
used, the following information should
be provided: a) physical  dimensions of
the unit (length, width, (or
circumference) depth,) sufficient  to
allow calculation of volume and the

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                                                                     19117
type, typical dose, and frequency with
which treatment chemicals are used;
  (4) The minimum and maximum
hydraulic loading the treatment unit
experiences, and;
  (5) Maximum backwash rate,
duration, typical filter run length, and
the number of filters at the plant.
  The State should use the above
information to determine which plants
need to modify recycle practice to
provide additional public health
protection. States are required to report
to EPA whether they required
individual direct filtration plants to
modify recycle practice and provide a
brief explanation of the reason(s) for the
decision.
  The Agency also considered requiring
that all direct filtration plants provide a
specific level of treatment for the
recycle flow. However, data necessary to
determine the appropriate level of
treatment is unavailable. Specifically,
the following data is needed:
  (1) Data on the on the occurrence of
oocysts in. the spent filter backwash of
direct filtration plants. Direct filtration
plants generally use higher quality
source water than conventional plants
(AWWA, 1990) and it would be
inaccurate to use spent filter backwash
occurrence data from conventional
plants to assess the level of treatment
direct recycle plants may need;
  (2) Data regarding the ability of
sedimentation and other clarification
processes to remove oocysts from
recycle flows is needed to determine
what may be a feasible level of
treatment. This data need was treated to
a detailed discussion in the previous
section of the preamble;
  (3)  An easy to measure and accurate
surrogate for oocyst removal is currently
unavailable; without such a surrogate, it
is not feasible to monitor the
performance of recycle treatment units,
and;
  (4) Data on the applicability of
microfiltration and ultrafiltration for
treating spent filter backwash produced
by direct filtration plants. This data
need was discussed in detail in the
previous section.
  Given the lack of  oocyst occurrence
data for direct filtration recycle streams,
and limited knowledge of the level of
treatment clarification processes can
achieve, the Agency does not currently
believe it is possible to identify a
treatment standard for direct filtration
plants.
iv. Request for Comments
  EPA requests comment on the
proposed requirements. The Agency
also requests comment on the following:
  (1) Whether direct filtration plants
should be required to provide treatment
for recycle flows;
  (2) The level of treatment direct
filtration plants should achieve;
  (3) Data that establishes turbidity,
particle counting, or some other
surrogate as an appropriate indicator of
oocyst removal achieved by recycle
treatment units, and;
  (4) Data on the ability of clarification
processes to remove oocysts and criteria
that can be  used to determine the
applicability of specific membrane
materials for treatment of spent filter
backwash produced by direct filtration
plants.

d. Request for Additional Comment    .
  EPA requests comment on  the
following:
  (1) Should the recycle of untreated
clarification sludges be allowed to
continue, or should the Agency ban this
practice? What affect would a ban have
on the operation of specific plant types,
such as softening plants?
  (2) Is it appropriate to apply
regulatory requirements to the
combined recycle flow rather than
stipulating  requirements for individual
recycle flows? Which flows should be
regulated individually and why?

V. State Implementation and
Compliance Schedules ,
  This section describes the regulations
and other procedures and policies States
have to adopt, or have in place, to
implement today's proposed rule. States
must continue to meet all other
conditions  of primacy in 40 CFR part
142.
  Section 1413  of the SDWA establishes
requirements that a State or eligible
Indian tribe must meet to maintain
primary enforcement responsibility
(primacy) for its public water systems.
These include: (1) Adopting drinking
water regulations that are no less
stringent than Federal NPDWRs in effect
under sections 1412(a) and 1412(b) of
the Act, (2) adopting and implementing
adequate procedures for enforcement,
(3) keeping records and making reports
available on activities that EPA requires
by regulation, (4) issuing variances and
exemptions (if allowed by the State)
under conditions no less stringent than
allowed by sections 1415 and 1416, and
(5) adopting and being capable of
implementing an adequate plan for the
provision of safe drinking water under
emergency situations.
  40 CFR part 142 sets out the specific
program implementation requirements
for States to obtain primacy for the
public water  supply supervision
program, as authorized under section
1413 of the Act. In addition to adopting
the basic primacy requirements, States
may be required to adopt special
primacy provisions pertaining to a
specific regulation. These regulation-
specific provisions may be necessary
where implementation of the NPDWR
involves activities beyond those in the
generic rule. States are required by 40
CFR 142.12 to include these regulation-
specific provisions in an application for
approval of their program revisions.
These State primacy requirements apply
to today's proposed rule, along with the
special primacy requirements discussed
below.
  To implement today's proposed rule,
States are required to adopt revisions to
§ 141.2—definitions; § 141.32—public
notification; § 141.70—general
requirements; § 141.73—filtration;
§ 141.76—recycle; § 141.153—content of
the reports; § 141.170—general
requirements; § 142.14—records kept by
States; § 142.16—special primacy
requirements; and a new subpart T,
consisting of § 141.500 to § 141.571.

A. Special State Primacy Requirements

  In addition to adopting drinking water
regulations at least as stringent as the
Federal regulations listed above, EPA
requires that States adopt certain
additional provisions related to this
regulation to have their program
revision application approved by EPA.
This information advises the regulated
community of State requirements and
helps EPA in its oversight of State
programs. States which require without
exception subpart H systems (all public
water systems using a surface water
source or a ground water source under
the direct influence of surface water) to
provide filtration, need not demonstrate
that the State program has provisions
that apply to systems which do not
provide filtration treatment. However,
such States must provide the text of the
State statutes or regulations which
specifies that public water systems
using a source water must provide
filtration.
  EPA is currently developing, with
stakeholders input, several guidance
documents to aid the States and water
systems in implementing today's
proposed rule. This includes guidance
for the following topics: Disinfection
benchmarking and profiling, Turbidity,
and Filter Backwash and Recycling.
EPA will also work with States to
develop a State implementation
guidance manual.
  To ensure that the State program
includes all the elements necessary for
a complete enforcement program, the
State's application must include the

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 following in order to obtain EPA's
 approval for implementing this rule:
   fl) Adoption of the promulgated
 LT1FBR.
   (2) Description of the procedures the
 State will use to determine the adequacy
 of changes in disinfection process by
 systems required to profile and
 benchmark under § 142.16(h)(2)(ii) and
 how the State will consult with PWSs
 to approve modifications to disinfection
 practice.
   (3) Description of existing or adoption
 of appropriate rules or other authority.
 under § 142.16(h)(l) to require systems
 to participate in a Comprehensive
 Technical Assistance (CTA) activity,
 and the performance improvement
 phase of the Composite Correction
 Program (CCP).
   (4) Description of how the State will
 approve a method to calculate the logs
 of inactivation for viruses for a system
 that uses either chloramines or ozone
 for primary disinfection.
   (5) For filtration technologies other
 than conventional filtration treatment,
 direct filtration, slow sand filtration or
 diatomaceous earth filtration, a
 description of how the State will
 determine under § 142.16(h)(2)(iii), that
 a public water system may use a
 filtration technology if the PWS
 demonstrates to the State, using pilot
 plant studies or other means, that the
 alternative filtration technology, in
 combination with the disinfection
 treatment that meets the requirements of
 Subpart T of this title, consistently
 achieves 99.9 percent removal and/or
 inactivation of Giardia lamblia cysts and
 99.99 percent removal and/or
 inactivation of viruses, and 99 percent
 removal of Cryptosporidium oocysts;
 and a description of how, for the system
 that makes this demonstration, the State
 will set turbidity performance
 requirements that the system must meet
 95 percent of the time and that the
 system may not exceed at any time a
 level that consistently achieves 99.9
 percent removal and/or inactivation of
 Giardia lamblia cysts, 99.99 percent
 removal and/or inactivation of viruses,
 and 99 percent removal of
 Cryptosporidium oocysts.
  (6) Description of the criteria the State
 will use under § 142.16(b)(2)(vi) to
 determine whether public water systems
 completing self assessments under
 § 141.76 (c) are required to modify
recycle practice and the criteria that will
be used to specify modifications to
recycle practice.
  (7) Description of the criteria the State
will use under § 142.16(b)(2)(vii) to
determine whether direct filtration
systems reporting data under § 141.76
(d) are required to change recycle
                     practice and the criteria that will be
                     used to specify changes to recycle
                     practice.
                       (8) The application must describe the
                     criteria the State will use under
                     § 142.16(bH2Hviii) to determine whether
                     public water systems applying for a
                     waiver to return recycle to a location
                     other than prior to the point of primary
                     coagulant addition, will be granted the
                     waiver for an alternative recycle
                     location.

                     B. State Recordkeeping Requirements
                      Today's rule includes changes to the
                     existing record-keeping provisions to
                     implement the requirements in today's
                     proposed rule. States must maintain
                     records of the following: (1) Turbidity
                     measurements must be kept for not less
                     than one year;
                      (2) disinfectant residual
                     measurements and other parameters
                     necessary to document disinfection
                     effectiveness must be kept for not less
                     than one year; (3) decisions made on a
                     system-by-system basis and  case-by-case
                     basis under provisions of part 141,
                     subpart H or subpart P or subpart T; (4]
                     records of systems consulting with the
                     State concerning a modification of
                     disinfection practice (including the
                     status of the consultation);
                      (5) records  of decisions that a system
                     using alternative filtration technologies
                     can consistently achieve a 99 percent
                     removal of Cryptosporidium oocysts as
                     well as the required levels of removal
                     and/or inactivation of Giardia and
                     viruses for systems using alternative
                     filtration technologies, including State-
                     set enforceable turbidity limits for each
                     system. A copy of the decision must be
                     kept until the decision is reversed or
                     revised and the State must provide a
                     copy of the decision to the system, and;
                     (6) records of systems required to do
                     filter self-assessments, CPE or CCP.
                     These decision records must be kept for
                     40 years (as currently required by
                     § 142.14 for other State decision
                    records) or until a subsequent
                     determination is made, whichever is
                    shorter.

                     C. State Reporting Requirements
                      Currently States must report to EPA
                    information under 40 CFR 142.15
                    regarding violations, variances and
                    exemptions, enforcement actions and
                    general operations of State public water
                    supply programs. Today's proposal
                    requires States to report a list of direct
                    recycle plants performing self
                    assessments, whether the State required
                    these systems to modify recycle
                    practice, and the reason(s)modifications
                    were or were not required and a list of
                    direct filtration plants performing self
 assessments, whether the State required
 these systems to modify recycle
 practice, and the reason(s) modifications
 were or were not required

 D. Interim Primacy
   On April 28, 1998, EPA amended its
 State primacy regulations at 40 CFR
 142.12 (63 FR 23362) (EPA 1998i) to
 incorporate the new process identified
 in the 1996 SDWA amendments for
 granting primary enforcement authority
 to States while their applications to
 modify their primacy programs are
 under review. The new process grants
 interim primary enforcement authority
 for a new or revised regulation during
 the period in which EPA is making a
 determination with regard to primacy
 for that new or revised regulation. This
 interim enforcement authority begins on
 the date of the primacy application
 submission or the effective date of the
 new or revised State regulation,
 whichever is later, and ends when EPA
 makes a proposed determination.
 However, this interim primacy authority
 is only available to a State that has
 primacy for every existing national
 primary drinking water regulation in
 effect when the new regulation is
 promulgated.
   As a result, States that have primacy
 for every existing NPDWR already in
 effect may obtain interim primacy for
 this rule, beginning on the date that the
 State submits  its final application for
 primacy for this rule to EPA, or the
 effective date  of its revised regulations,
 whichever is later. Interim primacy  is
 available for the following rules:
   •  Stage 1 Disinfectants and
 Disinfection Byproducts Rule
 (December 16, 1998)(EPA,1998c)
   • Interim Enhanced Surface Water
 Treatment Rule (EPA,1998a)
   • Consumer Confidence Report Rule
 (EPA, 1998f)
   • Variances and Exemptions Rule
 (EPA, 1998g)
   • Drinking Water Contaminant
 Candidate List (EPA, 1998h)
  • Revisions to State Primacy
 Requirements  (EPA,1998i)
  • Public Notification Rule (EPA,
 1999i)
  In addition,  a State which wishes to
 obtain interim primacy for future
 NPDWRs must obtain primacy for this
 rule. After the effective date of the final
 rule, any State that does not have
 primacy for this rule cannot obtain
 interim primacy for future rules.

E.  Compliance Deadlines
  Section 1412(b)(10) of SDWA
provides that drinking water rules
become effective 36 months after
promulgation unless the Administrator

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                                                                     19119
determines that an earlier time is
practicable. The Administrator may also
extend the effective date by an
additional 24 months if capital
improvements are necessary. The
Agency believes the three year effective
date is appropriate for all of the
provisions in today's notice except for
those provisions that address the return
of recycle flows. The Agency believes
providing a five year compliance period
for systems making modifications to
recycle practice is appropriate and
warranted under 1412(b)(10). To
effectively modify recycle practice,
capital improvements, such as installing
additional equipment and/or
constructing new facilities, will likely
be required. Specific examples of
potential capital improvements are
installing new piping and pumps to
convey recycle flow prior to the point of
primary coagulant addition and
constructing equalization basins or
recycle flow treatment facilities. A
limited number of systems may be able
to make operational modifications, per
the State's determination, that will
effectively address potential risks.
However, the Agency believes the great
majority of systems required to either
relocate their recycle return location or
modify recycle practice as directed by
the State will need to perform capital
improvements. The capital
improvement process is lengthy;
systems will need  to engage in
preliminary planning activities, consult
with State and local officials, develop
engineering and construction designs,
obtain financing, and construct the
facilities. The Agency believes the
widespread need that systems making
modifications to recycle practice will
have for capital improvements warrants
the additional 24 months for
compliance purposes. The Agency
solicits comment on the appropriateness
of providing an additional two years  for
compliance with the recycle provisions.
EPA seeks comment on extending the
compliance deadline an extra two years
because systems are expected to make
capital improvements to address recycle
practice.  EPA also seeks comment on a
similar two year extension to comply
with the turbidity provisions of today's
proposed rule.
II. Economic Analysis
   This section summarizes the Health
Risk Reduction and Cost Analysis in
 support of the Long Term 1 Enhanced
 Surface Water Treatment and Filter
 Backwash Rule (LT1FBR) as required by
 Section 1412(b)(3}(C) of the 1996
Amendments to the SDWA. In addition,
under Executive Order 12866,
Regulatory Planning and Review, EPA
must estimate the costs and benefits of
LTlFBR in a Regulatory Impact
Analysis (RIA) and submit the analysis
to the Office of Management and Budget
(OMB) in conjunction with publication
of the proposed rule. EPA has prepared
an RIA to comply with the requirements
of this Order and the SDWA Health Risk
Reduction and Cost Analysis (EPA,
1999h). The RIA has been published on
the Agency's web site, and can be found
at http://www.epa.gov/safewater. The
RIA can also be found in the docket for
this rulemaking.
  The goal of the following section is to
provide an analysis of the costs,
benefits, and other impacts of the
proposed rule to support future
decisions regarding the development of
the LTlFBR.

A. Overview

  The analysis for this rule examines
the costs and benefits for five rule
provisions: filter effluent turbidity,
applicability monitoring, disinfection
benchmark profiling, uncovered finish
water reservoirs, and recycle. Several
options were considered for each
provision. Costs were estimated for
three individual turbidity options, three
profiling options, and three
applicability monitoring options. In
addition, costs were estimated for four
different recycle options. All four
recycle options require spent filter
backwash, thickener supernatant, and
liquids from dewatering be returned to
the treatment process prior to the point
of primary coagulant addition. The
extent of modifications to recycle
practice varies among the rule options.
  The value of health benefits from the
turbidity provision was estimated for
the preferred option. The benefits from
the other rule provisions are described
qualitatively. Several non-health
benefits from this rule were also
considered by EPA but were not
monetized. The non-health benefits of
this rule include: avoided outbreak
response costs and possibly reduced
uncertainty and averting behavior costs.
By adding the non-monetized benefits
with those that are monetized, the
overall benefits of these rule options
increase beyond the dollar values
reported.
   Additional analysis was conducted by
EPA to look at the incremental impacts
 of the various rule options, impacts on
households, benefits from reductions in
 co-occurring contaminants, and possible
 increases in risk from other
 contaminants. Finally, the Agency
 evaluated the uncertainty regarding the
 risk, benefits, and cost estimates.
B. Quantifiable and Non-Quantifiable
Costs
  In estimating the costs of each rule
option, die Agency considered impacts
on public water systems and on States
(including territories and EPA
implementation in non-primacy States).
The LTlFBR will result in increased
costs to public water systems for
improved turbidity treatment,
applicability monitoring, disinfection
benchmarking, covering new finished
water reservoirs and modification to
recycle practice. States will also face
implementation costs. Most of the
provisions of this rule, except the
recycle provision, apply to systems
using surface water or ground water
under the direct influence of surface
water that serve less than 10,000 people.
The recycle provisions, however, apply
to all surface water systems that recycle
filter backwash, thickener supernatant,'
or liquids from dewatering.

1. Total Annual Costs
  EPA estimates that the annualized
cost of the preferred alternatives for the
proposed rule will be $97.5 million.
This estimate includes capital costs for
treatment changes and start-up labor
costs for monitoring and reporting
activities that have been annualized
assuming a 7% discount rate and a 20-
year amortization period. Other cost
estimates reported in this section also
use these same amortization
assumptions. The estimated cost of the
preferred alternatives also includes
annual operating and maintenance costs
for treatment changes and annual labor
for turbidity monitoring activities.
  The turbidity provisions (including
treatment changes, monitoring,  and
exceptions reporting) account for 70%
($68.6million annually) of total costs
and the recycling provisions (i.e.,
recycle to headworks, self assessment,
and direct filtration) account for 25%
($24.5 million annually) of total costs.
Utility expenditures for all provisions
equal almost 93% ($90.2 million
annually) of total costs; State
expenditures make up the other 7%
 ($6.7 million annually).
  To reduce the potential cost to small
systems, EPA developed and evaluated
the cost implications of several
regulatory alternatives for four of the
proposed LTlFBR provisions:
 individual filter turbidity monitoring,
 applicability monitoring, disinfection
benchmark profiling, and recycle. Many
 of these alternatives reduce the labor
burden on small systems relative to
 what it would be if the proposed rule
 used the same requirements as IESWTR.
 The total national costs previously

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 discussed only included the costs of the
 preferred alternatives. The following
 section will describe the cost estimates
 for each provision and discuss the cost
 of other alternatives that were
 considered.

 2. Annual Costs of Rule  Provisions
   The national estimate of annual utility
 costs for the proposed turbidity
 provisions is based on estimates of
 system-level costs for the various
 provisions of the rule and estimates of
 the number of systems expected to incur
 each type of cost.  The following
 paragraphs describe the  cost estimates
 for each of the rule provisions.

 Turbidity Provision Costs
   The turbidity provisions are estimated
 to cost $69.0 million annually. This cost
 is associated with three primary
 activities that result from this provision:
 treatment changes, monitoring, and
 exceptions reporting.
   The treatment costs associated with
 meeting the revised turbidity standard
 of 0.3 NTU or less are the main costs
 associated with the turbidity provision.
 EPA estimates  that 2,406 systems will
 modify their turbidity treatment in
 response to this rule. These costs are
 estimated to be $52.2 million annually.
 O&M expenditures account for 59%  of
 annual costs and the remain 41%
 percent is annualized capital costs.
   In addition to the turbidity treatment
 costs, turbidity monitoring costs apply
 to all small surface water or GWUDI
 systems using conventional or direct
 filtration methods. There are  an
 estimated 5,896 systems  that  fall under
 this criteria. EPA estimated the costs to
 utilities for three turbidity monitoring
 alternatives. Alternative B, the preferred
 alternative, excludes the  exceptions
 report for an individual filter exceeding
 0.5 NTU in two consecutive
 measurements, enabling  systems to shift
 from daily to weekly analysis and
 review of the monitoring data. The
 annualized individual filter turbidity
 cost to public water systems for this
 preferred option is approximately $10.1
 million. In contrast, under the IESWTR
 monitoring requirements of Alternative
 A, small systems would expend $63.3
 million annually for turbidity
 monitoring. Alternative C, which only
 requires monthly analysis is estimated
 to cost $5.6 million annually. The total
 state turbidity start-up and monitoring
 annual costs are $4.98 million annually
 and is assumed to be the  same for all of
the three alternatives.
  In addition to the turbidity  treatment
and monitoring costs,  individual filter
turbidity exceptions are estimated to
cost utilities $120 thousand annually for
                     the preferred option. State costs will be
                     approximately $1.17 million. This cost
                     includes the annual exception reports
                     and annual individual filter self.
                     assessment costs. Costs are slightly
                     higher for the other two alternative
                     individual filter turbidity monitoring
                     options because they result in increased
                     number of exception reports.

                     Disinfection Benchmarking Costs
                       Disinfection benchmarking involves
                     three components: profiling,
                     applicability monitoring, and
                     benchmarking. Four options were
                     costed for applicability monitoring.
                     Alternative 3, which uses the critical
                     monitoring period, is estimated to cost
                     less than $0.4 million annually.  This is
                     substantially lower than the $6.0
                     million estimated for Alternative 1,
                     which has the same requirements as
                     IESWTR. Alternative 2 requires
                     sampling once per quarter for 4 quarters
                     for systems serving 501-10,000,  but
                     allows systems under 500 to sample
                     once during the critical monitoring
                     period. This option has an annualized
                     cost of $1.1 million. The preferred
                     option, Alternative 4, makes it optional
                     to sample during the critical monitoring
                     period and is estimated to cost $0.04
                     million annualized.
                      Three options were considered for
                     disinfection profiling and
                     benchmarking. They differed in the
                     frequency and duration of data
                     collection. The preferred alternative,
                     Alternative 2, requires weekly
                     monitoring for one year and is estimated
                     to have an annualized cost of $0.8
                     million. In comparison, Alternative 1
                     which requires daily data collection for
                     one year, has an annualized cost of
                     approximately $1.3 million. The final
                     option, Alternative 3, requires daily
                     monitoring for 1 month and has an
                     estimated annualized cost of $0.5
                     million.
                      State disinfection benchmarking
                     annualized costs are estimated to be
                     $0.4 million. This estimate includes
                     start-up, compliance tracking/
                    recordkeeping, and benchmark related
                    costs.

                    Covered Finished Water Reservoir
                    Provision Costs
                      The proposed LT1FBR requires that
                    new systems cover all finished water
                    reservoirs, holding tanks, or other
                    storage facilities  for finished water.
                    Historical construction rates suggest that
                    new reservoirs over the next 20 years
                    will roughly equal to five percent of the
                    existing number  of systems. Assuming
                    then that 580 new uncovered finished
                    water reservoirs would be built in the
                    next 20 years, total annual costs,
 including annualized capital costs and
 one year of O&M costs are expected to
 be $2.6 million for this provision using
 a 7% discount rate. This estimate is
 calculated from a projected construction
 rate of new reservoirs and unit cost
 assumptions for covering new finished
 water reservoirs.

 Recycle Provision Cost
   EPA considered four different
 regulatory options for recycle. Each  of
 the four options requires spent filter
 backwash, thickener supernatant, and
 liquids from dewatering be returned
 prior to the point of primary coagulant
 addition. Alternative 1, is estimated to
 result in an annualized cost of $16.7
 million. Of the total costs of this
 alternative, State start-up and review
 costs  for this alternative are only $20 to
 $30 thousand annually.
   Alternative 2, the preferred option,
 further requires that conventional rapid
 granular filtration plants using surface
 water or GWUDI perform a self
 assessment if they recycle spent filter
 backwash and thickener supernatant,
 employ 20 or less filters, and practice
 direct recycle (treatment for the recycle
 flow or equalization in a basin that has
 a volume equal to the volume of spent
 filter backwash produced by a single
 filter backwash event is not provided).
 The results of the self assessment are
 reported to the State, and it specifies
 whether modifications to recycle
 practice are necessary. PWSs are
 required to implement the modification
 specified by the State. Under
 Alternative 2, direct filtration plants are
 required to submit data to the State on
 current recycle practice, and the State
 specifies whether changes to recycle
 practice are required. The total
 annualized cost of Alternative 2 is $17.4
 to $24.5 million. $0.4 to $5.9 million of
 the total annualized cost is for the direct
 recycle component, $0.1 to $1.7 million
 is for the direct filtration component,
 and the remaining cost is for the
 requirement to return recycle prior to
 the point of primary coagulant addition.
 Of the total costs of this alternative,
 State start-up, review, and self
 assessment costs for  this alternative is
 only $115 thousand annually.
  Alternative 3 contain the same
 requirements for direct filtration plants
 and also requires the three recycle flows
 mentioned above be returned prior to
 the point of primary  coagulant addition.
 Direct recycle plants are required to
 install equalization basins with a
 volume equal to or greater than the
 volume produced by two filter
backwash events. The annualized cost
 of Alternative 3 is $55.0 to $56.7
million. Of this range, $38.1 million of

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                                                                    19121
the annualized cost is directly
associated with requiring direct recycle
plants to install equalization, and $0.1
to SI.7 million is associated with the
direct filtration component. State start-
up and self assessment costs for this
alternative is $95 thousand annually.
  Alternative 4 requires the three
recycle flows mentioned above be
returned prior to the point of primary
coagulant addition and also requires
that all systems that recycle
(conventional and direct systems) install
sedimentation basins for recycle flow
treatment. Systems may also install
recycle flow treatment technologies that
provide treatment capability equivalent
or superior to sedimentation. For cost
estimation purposes, sedimentation
basins with tube settlers and polymer
addition where used. The Agency
approximated the annualized costs of
this option to be $151.8 million. The
sedimentation basin treatment
requirement for conventional and direct
filtration plants is 88% ($133.3 million)
of the total annualized cost of
Alternative 4. State start-up and self
assessment costs for this alternative is
$100 thousand annually.
3. Non-Quantifiable Costs
  Although EPA has estimated the cost
of all the rule's components on drinking
water systems and States, there are some
costs that the Agency did not quantify.
These non-quantifiable costs result from
uncertainties surrounding rule
assumptions and from modeling
assumptions. For example, EPA did not
estimate a cost for systems to acquire
land if they needed to build a treatment
facility or significantly expand their
current facility. This was not costed
because many systems will be able to
construct new treatment facilities on
land already owned by the utility. In
addition, if the cost of land was
prohibitive, a system may choose
another lower cost alternative such as
connecting to another source. A cost for
systems choosing this alternative is
unquantified in our analysis.
 C. Quantifiable and Non-Quantifiable
Health Benefits
   The primary benefits of today's
proposed rule come from reductions in
the risks of microbial illness from
 drinking water. In particular, LTlFBR
 focuses on reducing the risk associated
 with disinfection resistant pathogens,
 such as Cryptosporidium. Exposure to
 other pathogenic protozoa, such as
 Giardia, or other waterborne bacteria,
 viral pathogens, and other emerging
pathogens are likely to be reduced by
the provisions of this rule as well but
are not quantified. In addition, LTlFBR
produces nonquantifiable benefits
associated with the risk reductions that
result from the recycle provision,
uncovered reservoirs provision,
including Cryptosporidium in GWUDI
definition, and including
Cryptosporidium in watershed
requirements for unfiltered systems.

1. Quantified Health Benefits
a. Turbidity Provisions
   The quantification of benefits from
this rule is focused solely on reductions
in the risk of cryptosporidiosis.
Cryptosporidiosis is an infection caused
by Cryptosporidium which is an acute,
self-limiting illness lasting 7 to 14 days
with symptoms that include diarrhea,
abdominal cramping, nausea, vomiting
and fever (Juranek, 1995). The cost of
illness avoided of cryptosporidiosis is
estimated to have a mean of $2,016
(Harrington et al., 1985; USEPA 1999h)
   The benefits of the turbidity
provisions of LTlFBR come from
improvements in filtration performance
at water systems. The benefits analysis
attempts to take into account some of
the uncertainties in the analysis by
estimating benefits under two different
current treatment and three improved
removal assumptions. The benefits
analysis also used Monte Carlo
simulations to derive a distribution of
estimates, rather than a single point
estimate.
   The benefits analysis focused on
estimating changes in incidence of
cryptosporidiosis that would result from
the rule. The analysis included
estimating the baseline (pre-LTlFBR)
level of exposure from Cryptosporidium
in drinking water, reductions in such
exposure resulting from treatment
changes to comply with the LTlFBR,
and resultant reductions of risk.
   Baseline levels of Cryptosporidium in
finished water were estimated by
assuming national source water
occurrence distribution (based on data
by LeChevallier and Norton, 1995) and
a national distribution of
Cryptosporidium removal  by treatment.
   In the LTlFBR RIA, the  following two
assumptions were made regarding the
current Cryptosporidium oocyst
performance to estimate finished water
Cryptosporidium concentrations. First,
based on treatment removal efficiency
data presented in the 1997 IEWSTR,
EPA  assumed a national distribution of
physical removal efficiencies with a
mean of 2.0 logs and a standard
deviation oft 0.63 logs. Because the
finished water concentrations of oocysts
represent the baseline against which
improved removal from the LTlFBR is
compared, variations in the log removal
assumption could have considerable
impact on the risk assessment. Second,
to evaluate the impact of the removal
assumptions on the baseline and
resulting improvements, an alternative
mean log removal/inactivation
assumption of 2.5 logs and a standard
deviation of ± 0.63 logs was also used
to calculate finished water
concentrations of Cryptosporidium.
  For each of the two baseline
assumptions, EPA assumed that a
certain number of plants would show
low, mid or high improved removal,
depending upon factors such as water
matrix conditions, filtered water
turbidity effluent levels, and coagulant
treatment conditions. As a result, the
RIA considers six scenarios that
encompass the range of endemic health
damages avoided based on the rule.
  The finished water Cryptosporidium
distributions that would result from
additional log removal with the
turbidity provisions, were derived
assuming that additional log removal
was dependent on current removal, i.e.,
that sites currently operating at the
highest filtered water turbidity levels
would show the largest improvements
or high improved removal assumption
(e.g., plants now failing to meet a 0.4
NTU limit would show greater removal
improvements than plants now meeting
a 0.3 NTU limit).
  Table VI. 1 indicates estimated annual
benefits associated with implementing
the LTlFBR. The benefits analysis
quantitatively examines endemic health
damages avoided based on the LTlFBR
for each of the six scenarios mentioned
above. For each of these scenarios, EPA
calculated the mean of the distribution
of the number of illnesses avoided. The
10th and 90th percentiles imply that
there is a 10 percent chance that the
estimated value could be as low as the
10th percentile and there is a 10 percent
chance that the estimated value could
be as high as the 90th percentile. EPA's
Office of Water has evaluated drinking
water consumption data from USDA's
1994-1996 Continuing Survey of Food
Intakes by Individuals (CSFII) Study.
EPA's analysis  of the CSFII Study
resulted in a daily water ingestion
lognormally distributed with a mean of
1.2 liters per person (EPA, 2000a). The
risk and benefit analysis contained
within the RIA reflects this distribution.

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Federal Register/Vol.  65, No. 69/Monday, April 10, 2000/Proposed Rules
           TABLE VI.1.—NUMBER AND VALUE OF ILLNESSES AVOIDED ANNUALLY FROM TURBIDITY PROVISIONS
                                                [Dollar amounts in billions]
Improved Log-Removal Assumption
Illnesses Avoided with Low Improved Cryptosporidium Removal Assumption:
Mean 	
10th Percentile 	
90th Percentile 	
COI Avoided with Low Improved Cryptosporidium Removal Assumption:
Mean 	
10th Percentile 	
90th Percentile 	
Illnesses Avoided with Mid Improved Cryptosporidium Removal Assumption:
Mean 	
10th Percentile 	
90th Percentile 	
COI Avoided with Mid Improved Cryptosporidium Removal Assumption:
Mean 	
10th Percentile 	
90th Percentile 	
Illnesses Avoided with High Improved Cryptosporidium Removal Assumption:
Mean 	
10th Percentile 	
90th Percentile 	
COI Avoided with High Improved Cryptosporidium Removal Assumption:
Mean 	
10th Percentile 	
90th Percentile 	
Daily Drinking Water Ingestion
and Baseline Cryptosporidium
Log-Removal Assumptions
(Mean = 1 .2 Liters per person)
2.0 log
62,800.0
0.0
152,000.0
$150.3
$0.0
$288.2
77,500.0
0.0
184,000.0
$185.3
$0.0
$350.9
83,600.0
0.0
196,000.0
$199.5
$0.0
$376.7
2.5 log
22,800.0
0.0
43,900.0
$53.9
$0.0
$81.4
27,900.0
.00
52,900.0
$66.2
$0.0
$98.8
30,000.0
0.0
56,500.0
$71.1
$0.0
$105.8
  "All values presented are in January 1999 dollars.
  According to the RIA performed for
the LTlFBR published today, the rule is
estimated to reduce the mean annual
number of illnesses caused by
Cryptosporidium in water systems with
improved filtration performance by
22,800 to 83,600 cases depending upon
which of the six baseline and improved
Cryptosporidium removal assumptions
was used, and assuming the 1.2 liter
drinking water consumption
distribution. Based on these values, the
mean estimated annual benefits of
reducing the illnesses ranges from $54
million to $200 million per year. The
RIA also indicated that the rule could
result in a mean reduction of 3 to 10
fatalities each year, depending upon the
varied baseline and improved removal
assumptions. Using a mean value of
$5.7 million per statistical life saved,
reducing these fatalities could produce
benefits in the range of $16.0 million to
$60 million.
  Combining the value of illnesses and
mortalities avoided, the total benefits
range from $70 million to $260 million
assuming a 1.2 liter drinking water
consumption distribution.
b. Sensitivity Analysis for Recycle
Provisions
  Available literature research
demonstrates that increased hydraulic
                    loading or disruptive hydraulic
                    currents, such as may be experienced
                    when plants exceed State-approved
                    operating capacity or when recycle is
                    returned directly into the sedimentation
                    basin, can disrupt filter (Cleasby, 1963;
                    Glasgow and Wheatley, 1998; McTigue
                    et al, 1998) and sedimentation (Fulton,
                    1987; Logsdon, 1987; Cleasby, 1990)
                    performance. However, the literature
                    does not quantify the extent to which
                    performance can be lowered and, more
                    specifically, does not quantify the log
                    reduction in Cryptosporidium removal
                    that may be experienced during direct
                    recycle events.
                      In the absence of quantified log
                    reduction data, the Agency performed a
                    sensitivity analysis to estimate a range
                    of potential benefit provided by the
                    recycle provisions. The analysis
                    assumes a baseline Cryptosporidium log
                    removal value of 2.0. The analysis
                    estimates the effect of recycle by
                    reducing the average baseline  log
                    removal by a range of values (reduction
                    ranged from 0.05 to 0.50 log) to account
                    for the reduction in removal
                    performance plants may experience if
                    they exceed State-approved operating
                    capacity or return recycle to the
                    sedimentation basin. The installation of
                    equalization to eliminate exceedence of
 State-approved operating capacity or
 moving the recycle return location from
 the sedimentation basin to prior to the
 point of primary coagulant addition will
 result in the health benefit. The benefit
 estimate is conservative, because it does
 not account for the fact that recycle
 returns additional oocysts to the plant.
  Benefits are estimated by assuming
 that the installation of equalization or
 moving the recycle return point prior to
 the point of primary coagulant addition
 will return the plant to the baseline
 Cryptosporidium removal of 2.0 log. The
 difference between the number of
 illnesses that result from the baseline
 situation and the reduced performance
 is used to  calculate the monetary
benefit. The benefit is compared to the
cost of returning recycle prior to the
point of primary coagulant additional
and the cost of installing equalization
for two service populations. Service
populations of 1,900 persons, which
represents a plant serving fewer than
10,000 people, and a service population
of 25,108,  which represents a plant
serving greater than  10,000 people, are
used. Results are summarized in Tables
IV.2 and IV.3 below.

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                                                                     19123
                             TABLE IV.2.—BENEFIT FOR SERVICE POPULATION OF 1,900
Log removal reduction
0 05 	
0.50 	 	
Benefit" for
population of
1,900
$1,400
30,700
Costa of moving
recycle return
$5,200
5,200
Cost" of install-
ing equalization
$25,200
25,290
  "Cost and benefit are annualized with a 7% capital cost over 20 years.

                         TABLE IV.3.—BENEFIT RANGE FOR SERVICE POPULATION OF 25,108
Log removal reduction
0 05 	
0.50 	
] Benefit" for
population of
25,108
$18,700
405,800
Cost" of moving
recycle return
$18,700
18,700
Cost" of install-
ing rqualization
i
$57,200
57,200
  »Cost and benefit are annualized with a 7% capital cost over 20 years.
  Although literature research does not
quantify the log reduction caused by
specific recycle practices, the results of
the sensitivity analysis show that the
benefit a plant serving 25,108 people
would realize by improving its baseline
performance to 2.0 logs would range
from $18,700 to $405,800. $27,256
Benefits would range from $1,400 to
$30,700 for a plant serving 1,900. This
benefit range supports the Agency's
determination that unqualified benefits
will justify costs. The determination is
discussed in the Benefit Cost
Determination section.
2. Non-Quantified Health and Non-
Health Related Benefits
a. Recycle Provisions
  The benefits associated with the filter
backwash provision are unquantified
because of data limitations. Specifically,
there is a lack of treatment performance
data to accurately model the oocysts
removal achieved by individual full-
scale treatment processes and the
impact recycle may have on treatment
unit performance and finished water
quality. Additional data on the ability of
unit processes (sedimentation, DAF,
contact clarification, filtration) to
remove oocysts from source and recycle
flows, the extent to which recycle may
generate hydraulic surge within plants
and lower the performance of individual
treatment processes, data on the
potential for recycle to threaten the
integrity of chemical treatment, and
additional information on the
occurrence of oocysts in recycle streams
are all needed before an impact model
can be calibrated and used as a
predictive tool.
  However, available  data demonstrate
that oocysts occur in recycle streams,
often at concentrations higher than
found in source water, and returning
recycle streams to the plant will
increase intra-plant oocyst
concentrations. Data also shows that
oocysts frequently occur in the finished
water of treatment plants that are not
operating under stressed conditions.
Engineering literature also shows that
proper coagulation and the maintenance
of balanced hydraulic conditions within
the plant [i.e., not exceeding State
approved sedimentation/clarification
and filtration operating rates) are
important to protect the integrity of the
entire treatment process. Some recycle
practices, such as direct recycle, can
potentially upset coagulation and the
proper hydraulic operation of
sedimentation/clarification and
filtration processes. The benefits  of the
recycle provisions are derived from
protecting the coagulation process and
the hydraulic performance of
sedimentation/clarification and
filtration processes. Today's recycle
provisions reduce the risk posed  by
recycle and provided additional public
health protection in the following ways:
  (1) Returning spent filter backwash,
thickener supernatant, and liquids from
dewatering into, or downstream of, the
point of primary coagulant addition may
disrupt treatment chemistry by
introducing residual coagulant or other
treatment chemicals to  the process
stream. The wide variation in plant
influent flow can also result in chemical
over-or under-dosing if chemical dosage
is not adjusted to account for flow
variation. Returning the above  flows
prior to the point of primary coagulant
addition will help  protect tie integrity
of coagulation and protect the
performance of downstream unit
processes, such as  clarification and
filtration, that require proper
coagulation be conducted to maintain
proper performance. This will  provide
an additional measure of public health
protection.
  (2) The direct recycle of spent filter
backwash without first providing
treatment, equalization, or some form of
hydraulic detention for the flow, may
cause plants to exceed State-approved
operating capacity during recycle
events. This may lead to lower overall
oocyst removal performance due to the
hydraulic overload unit processes (i.e.,
clarification and filtration) experience
and increase finished water oocyst
concentrations. The self assessment
provision in today's rule will help the
States identify direct recycle systems
that may experience this problem so
modifications to recycle practice can be
made to protect public health.
  (3) Direct filtration plants do not
employ a sedimentation basin in their
primary treatment process to remove
solids and oocysts; all oocyst removal is
achieved by the filters. If treatment for
the recycle flow is not provided prior to
its return to the plant, all of the oocysts
captured by a filter during a filter run
will be returned to the plant and again
loaded to the filters. This may lead to
ever increasing levels of oocysts being
applied to the filters and could increase
the concentration of oocysts in finished
water. Today's provision for direct
recycle systems will help States identify
those systems that are not obtaining
sufficient oocyst removal from the
recycle flow. Public health protection
will be increased when systems
implement modifications to recycle
practice specified by the State.
  The goal of the recycle provisions is
to reduce the potential for oocysts
getting into the finished water and
causing cases of cryptosporidiosis.
Other disinfection resistant pathogens
may also be removed more efficiently
due to implementation of these
provisions.

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 b. Issues Associated With Unquantified
 Benefits
   The monetized benefits from filter
 performance improvements are likely
 not to fully capture all the benefits of
 the turbidity provisions. EPA monetized
 the benefits from reductions in
 cryptosporidiosis by using  cost-of-
 illness (COI) estimates. This may
 underestimate the actual benefits of
 these reductions because COI estimates
 do not include pain and suffering. In
 general, the COI approach is considered
 a lower bound estimate of willingne'ss-
 to-pay (WTP) to avoid illnesses. EPA
 requests comment on the use of an
 appropriate WTP study to calculate the
 benefits of this rule.
   Several non-health benefits from this
 rule were also considered by EPA but
 were not monetized. The non-health
 benefits of this rule include avoided
 outbreak response costs and possibly
 reduced uncertainty and averting
 behavior costs. By adding the non-
 monetized benefits with those that are
 monetized, the overall benefits of this
 rule would increase beyond the dollar
 values reported.

 D. Incremental Costs and Benefits
  EPA evaluated the incremental or
 marginal costs of today's proposed
 turbidity option by analyzing various
 turbidity limits, 0.3 NTU, 0.2 NTU, and
 0.1 NTU. For each turbidity limit, EPA
 developed assumptions about which
 process changes systems might
 implement to meet the turbidity level
 and how many systems would adopt
 each change. The comparison of total
 compliance cost estimates show that
 costs are expected to increase
 significantly across turbidity limits. The
 total cost of a 0.1 NTU limit, $404.6
 million, is almost eight times higher
 than the cost of the 0.3 NTU limit,
 which is $52.2 million. Similarly, the
 total cost of the 0.2 NTU limit, $134.1
 million, is more than twice  as great as
 the 0.3 NTU cost.
  Analytical limitations in the
 estimation of the benefits of LTlFBR
 prevent the Agency from quantitatively
 describing the incremental benefits of
 alternatives. The Agency requests
 comment on how to analyze and the
 appropriateness of analyzing
 incremental benefits and costs for
 treatment techniques that address
 microbial contaminants.

 E. Impacts on Households
  The cost impact of LTlFBR at the
 household level was also assessed.
 Household costs are a way to represent
 water system treatment costs as costs to
the system's customers. As expected,
                     costs per household increase as system
                     size decreases. Costs to households are
                     higher for households served by smaller
                     systems than larger systems for two
                     reasons. First, smaller systems serve far
                     fewer households than larger systems,
                     and consequently, each household must
                     bear a greater percentage share of capital
                     and O&M costs. Second, filter backwash
                     recycling may pose a greater risk
                     because the flow of water from filter
                     backwash recycling is a larger portion of
                     the total water flow in smaller systems.
                     This greater risk potential in small
                     systems makes it more likely that some
                     form of recycle treatment might be
                     needed.
                      The average (mean) annual cost for
                     the turbidity, benchmarking, and
                     covered finished water provision per
                     household is $8.66. For almost 86
                     percent of the 6.6 million households
                     affected by these provisions, the per-
                     household costs are $10 per year or less,
                     and costs of $120 per year (i.e., $10 per
                     month) or less for approximately 99
                     percent of the households. Costs
                     exceeding $500 per household occur
                     only for the smallest size category, and
                     the number of affected households
                     represent about 34  of the smallest
                     systems. The highest per-household cost
                     estimate is $2,177.  This extreme
                     estimate, however, is an artifact of the
                     way the system cost distribution was
                    generated. It is unlikely that any small
                     system will incur annual costs of this
                    magnitude because less costly options
                    are available.
                      The average household cost for the
                    recycle provisions is $1.80 per year for
                    households that are served by systems
                    that recycle. The cost per household is
                    less than $10 per year for almost 99%
                    of 12.9 million households potentially
                    affected by the proposed rule. The  cost
                    per household exceeds $120 per year for
                    less than 1800 households and it
                    exceeds $500 per year for approximately
                    100 households. The maximum cost of
                    $1,238 per year would only be incurred
                    if a direct filtration system that serves
                    less than 100 customers installed a
                    sedimentation basin for backwash
                    treatment.
                      There are approximately 1.5 million
                    households served by small drinking
                    water systems that may be affected by
                    the recycling provisions in addition to
                    the turbidity, benchmarking, and
                    covered finished water provisions.  The
                    expected aggregate annual cost to these
                    households can be approximated by the
                    sum of the expected cost for each
                    distribution, which is $10.45 per year.
                      The assumptions and structure of this
                    analysis tend to overestimate the highest
                    costs. To face the highest household
                    costs, a system would have to
 implement all, or almost all, of the
 treatment activities. These systems,
 however, might seek less costly
 alternatives, such as connecting into a
 larger regional water system.

 F. Benefits From the Reduction of Co-
 Occurring Contaminants
   If a system chooses to install
 treatment, it may choose a technology
 that would also address other drinking
 water contaminants. For example, some
 membrane technologies installed to
 remove bacteria or viruses can reduce or
 eliminate many other drinking water
 contaminants including arsenic.
   The technologies used to reduce
 individual filter turbidities have the
 potential to reduce concentrations of
 other pollutants as well. Reduction in
 turbidity that result from today's
 proposed rule are aimed at reducing
 Cryptosporidium by physical removal. It
 is reasonable to assume that similar
 microbial contaminants will also be
 reduced as a result of improvements in
 turbidity removal. Health risks from
 Giardia lamblia and emerging
 disinfection resistant pathogens, such as
 microsporidia, Toxoplasma, and
 Cyclospora, are also likely to be reduced
 as a result of improvements in turbidity
 removal and recycle practices.  The
 frequency and extent that LTlFBR
 would reduce risk from other
 contaminants has not been
 quantitatively evaluated because of the
 Agency's lack of data on the removal
 efficiencies of various technologies for
 emerging pathogens and the lack of co-
 occurrence data for microbial pathogens
 and other contaminants from drink
 water systems.

 G. Risk Increases From Other
 Contaminants
  It is unlikely that LTlFBR will result
 in any increased risk from other
 contaminants. Improvements in plant
 turbidity performance will not result in
 any increases in risk. In addition, the
 benchmarking and profiling provisions
 were  designed to minimize the potential
 reductions in microbial disinfection in
 order to lower disinfection byproduct
 levels to comply with the Stage 1
 Disinfection Byproducts Rule.
 Furthermore, the filter backwash
 provision does not potentially increase
 the risk from other contaminants.

 H. Other Factors: Uncertainty in Risk,
 Benefits, and Cost Estimates
  There is uncertainty in the baseline
 number of systems, the risk calculation,
 and the cost estimates. Many of these
uncertainties are discussed in more
 detail in previous sections of today's
proposal.

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                  Federal Register/Vol. 65, No. 69/Monday,  April 10, 2000/Proposed Rules
                                                                    19125
  First, the baseline number of systems
is uncertain because of data limitation
problems in SDWIS. For example, some
systems use both ground and surface
water but because of other regulatory
requirements are labeled in SDWIS as
surface water. Therefore, EPA does not
have a reliable estimate of how many of
these mixed systems exist. The SDWIS
data on non-community water systems
does not have a consistent reporting
convention for population served. Some
states may report the population served
over the course of a year, while others
may report the population served on an
average day. Also, SDWIS does not
require states to provide information on
current filtration practices and, in some
cases, it may overestimate the daily
population served. For example, a park
may report the population served yearly
instead of daily. EPA is looking at new
approaches to address these issues and
both are discussed below in request for
comment.
  Second, there are several important
sources of uncertainty that enter the
benefits assessment. They include the
following:
  • Occurrence of Cryptosporidium
oocysts in source waters
  • Baseline occurrence of
Cryptosporidium oocysts in finished
waters
  • Reduction of Cryptosporidium
oocysts due to improved treatment,
including filtration and disinfection
  • Viability of Cryptosporidium
oocysts after treatment
  • Inactivity of Cryptosporidium
  • Incidence of infections (including
impact of under reporting)
  • Characterization of the risk
Willingness-to-pay to reduce risk and
avoid costs.
  • The baseline water system
treatment efficiency for the removal of
Cryptosporidium is uncertain. Turbidity
measurements have been used as a
means of estimating removal treatment
efficiency (i.e. log removal). In addition
to the baseline treatment efficiency
estimates, improvements in treatment
efficiency for Cryptosporidium removal
that result from this rule are uncertain.
  The benefit  analysis incorporates all
of the uncertainties associated with the
benefits assessment in either the Monte
Carlo simulations or the assumption of
two baselines—2.0 log removal and 2.5
log removal. The results in table VI. 1
show that benefits are more sensitive to
the baseline log removal assumptions
than the range of low to high improved
removal assumptions. Third, some costs
of today's proposed rule are uncertain
because ofthe diverse nature of the
modifications that may be made to
address turbidity limits. Cost analysis
uncertainties are primarily caused by
assumptions made about how many
systems will be affected by various
provisions and how they will likely
respond. Capital and O&M expenditures
account for a majority of total costs. EPA
derived these costs for a "model"
system in each size category using
engineering models, best professional
judgement, and existing cost and
technology documents. Costs for
systems affected by the proposed rule
could be higher or lower, which would
affect total costs. Also, the filter
backwash provision's flexibility for
States to assess plants' need to modify
recycle practices leads to some
uncertainty in the estimates of how
many plants will have to potentially
install some form of recycle equalization
or treatment. These uncertainties could
either under or overestimate the costs of
the rule.
I. Benefit Cost Determination
  The Agency has determined that the
benefits ofthe LT1FBR justify the costs.
EPA made this determination for both
the LTl and the FBR portions of the rule
separately as described below.
  The Agency has determined that the
benefits of the LTl provisions justify
their costs on a quantitative basis. The
LTl provisions include enhanced
filtration, disinfection benchmarking  ,
and other non-recycle related
provisions. The quantified benefits of
$70 million to $259.4 million annually
exceed the costs of $73 million at the
seven percent cost of capital over a
substantial portion of the range of
benefits. In addition, the non-quantified
benefits include avoided outbreak
response costs and possibly reduced
uncertainty and averting behavior costs.
   The Agency has determined that the
benefits of the recycle provisions (FBR)
justify their cost on a qualitative basis,
The recycle provisions will reduce the
potential for certain recycle practices to
lower or upset treatment plant
performance during recycle events; the
provisions will therefore help prevent
Cryptosporidium oocysts from entering
finished drinking water supplies and
will increase public health protection.
   The Agency strongly believes that
returning Cryptosporidium to the
treatment process in recycle flows, if
performed improperly, can create
additional public health risk. The
Agency holds this belief for three
reasons. First, returning recycle flow
directly to the plant, without
equalization or treatment, can cause
large variations in the influent flow
magnitude and influent water quality. If
chemical dosing is not adjusted to
reflect this, less than optimal chemical
dosing can occur, which may lower the
performance of sedimentation and
filtration. Returning recycle flows prior
to the point of primary coagulant
addition will help diminish the risk of
less than optimal chemical dosing and
diminished sedimentation and filtration
performance. Second, exceeding State-
approved operating capacity, which is
likely to occur if recycle equalization or
treatment is not in place, can
hydraulically overload plants and
diminish the ability of individual unit
processes to remove Cryptosporidium.
Exceeding approved operating capacity
violates fundamental engineering
principles and water treatment
objectives. States set limits on plant
operating capacity and loading rates for
individual unit processes to ensure
treatment plants and individual
treatment processes are operated to    :
within their capabilities so that
necessary levels  of public health
protection are provided. Third,
returning recycle flows directly into
flocculation or sedimentation basins,
which can generate disruptive hydraulic
currents, may lower the performance of
these units and increase the risk of
Cryptosporidium in finished water
supplies.
  The recycle provisions in today's
proposal are designed to address those
recycle practices that are inconsistent
with fundamental engineering and
water treatment principles. The
objective of the provisions is to
eliminate practices that are counter to
common sense, sound engineering
judgement, and that create additional
and preventable risk to public health.
EPA believes the public health
protection benefit provided by the
recycle provisions justifies their cost
because they are based upon sound
engineering principles and are designed
to eliminate recycle practices that are
very likely to create additional public
health risk.
/. Request for Comment
  Pursuant to Section 3142(b)(3)(C), the
Agency requests comment on all aspects
of the rule's economic impact analysis.
Specifically, EPA seeks input into the
following two issues.

NTNC and TNC Flow Estimates
  As part of the  total cost estimates for
LTlFBR, EPA estimated the cost ofthe
rule on NTNC and TNC water systems
by using flow models. However, these ,
flow models were developed to estimate
flows only for CWS and they may not
accurately represent the much smaller
flows generally found in NTNC and
TNC systems. The effect ofthe
overestimate in flow would be to inflate

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 the cost of the rule for these systems.
 The Agency requests comment on an
 alternative flow analysis for NTNC and
 TNG water systems described below.
   Instead of using the population served
 to determine the average flow for use in
 the rule's cost calculations, this
 alternative approach would re-
 categorize NTNC and TNG water
 systems based on service type (e.g.,
 restaurants or parks). Service type
 would be obtained from SDWIS data.
 However, service type data is not always
 available because it is a voluntary
 SDWIS data field. Where unavailable,
 the service type would be assigned
 based on statistical analysis. Estimates
 of service type design flows would be
 obtained from engineering design
 manuals and best professional
 judgement if no design manual
 specifications exist.
   In addition, each service type category
 would also have corresponding rates for
 average population served and average
 water consumption. These would be
 used to determine contaminant
 exposure which is used in the benefit
 determination. For example, schools
 and churches would be two separate
 service type categories. They each
 would have their own corresponding
 average design flow, average population
 served (rather than the population as
 reported in SDWIS), and average water
 consumption rates. These elements
 could be used to estimate a rule's
 benefits and costs for the average church
 and the average school.

 Mixed Systems
  Current regulations require that all
 systems that use any amount of surface
 water as.a source be categorized as
 surface water systems. This
 classification applies even if the
 majority of water in a system is from a
 ground water source. Therefore, SDWIS
 does not provide the Agency with
 information to identify how many
 mixed systems exist. This information
 would help the Agency to better
 understand regulatory impacts.
  EPA is investigating ways to identify
 how many mixed systems exist and how
 many mix their ground and surface
 water sources at the same entry point or
 at separate entry points within the same
 distribution systems. For example, a
 system may have several plants/entry
 points that feed the same distribution
system. One of these entry points may
mix and treat surface water with ground
water prior to its entry into the
 distribution system. Another entry point
might use ground water exclusively for
its source while a different entry point
would exclusively use surface water.
However, all three entry points would
                     supply the same system classified in
                     SDWIS as surface water.
                      One method EPA could use to address
                     this issue would be to analyze CWSS
                     data then extrapolate this information to
                     SDWIS to obtain a national estimate of
                     mixed systems. CWSS data, from
                     approximately 1,900 systems, details
                     sources of supply at the level of the
                     entry point to the distribution system
                     and further subdivides flow by source
                     type. The Agency is considering this
                     national estimate of mixed systems to
                     regroup surface water systems for
                     certain impact analyses when
                     regulations only impact one type of
                     source. For example, surface water
                     systems that get more than fifty percent
                     of their flow from ground water would
                     be counted as a ground water system in
                     the regulatory impact analysis for this
                     rule. The Agency requests comment on
                     this methodology and its applicability
                     for use in regulatory impact analysis.

                     VII. Other Requirements

                    A. Regulatory Flexibility Act  (RFA), as
                     amended by the Small Business
                    Regulatory Enforcement Fairness Act of
                     1996 (SBREFA), 5 USC 601 et seq.

                     1. Background
                      The RFA, generally requires an
                    agency to prepare a regulatory flexibility
                    analysis of any rule subject to notice
                    and comment rulemaking requirements
                    under the Administrative Procedure Act
                    or any other statute unless the agency
                    certifies that the rule will not have a
                    significant economic impact on a
                    substantial number of small entities.
                    Small entities include small businesses,
                    small organizations, and small
                    governmental jurisdictions.

                    2. Use of Alternative Definition
                      The RFA provides default definitions
                    for each type of small entity. It also
                    authorizes an agency to use alternative
                    definitions for each category of small
                    entity, "which are appropriate to the
                    activities of the agency" after proposing
                    the alternative definition(s) in the
                    Federal Register and taking comment. 5
                    U.S.C. sees. 601(3)-(5). In addition to
                    the above, to establish an alternative
                    small business definition,  agencies must
                    consult with SBA's Chief Counsel for
                    Advocacy.
                     EPA is proposing the LTlFBR which
                    contains provisions which apply to
                    small PWSs serving fewer than 10,000
                    persons. This is the cut-off level
                    specified by Congress in the 1996
                    Amendments to the Safe Drinking Water
                    Act for small system flexibility
                    provisions. Because this definition  does
                    not correspond to the definitions of
                    "small" for small businesses,
 governments, and non-profit
 organizations, EPA requested comment
 on an alternative definition of "small
 entity" in the preamble to the proposed
 Consumer Confidence Report (CCR)
 regulation (63 FR 7620, February 13,
 1998). Comments showed that
 stakeholders support the proposed
 alternative definition. EPA also
 consulted with the SBA Office of
 Advocacy on the definition as it relates
 to small business analysis. In the
 preamble to the final CCR regulation (63
 FR 4511, August 19,1998). EPA stated
 its intent to establish this alternative
 definition for regulatory flexibility
 assessments under the RFA for all
 drinking water regulations and has thus
 used it in this proposed rulemaking.
   In accordance with Section 603 of the
 RFA, EPA prepared an initial regulatory
 flexibility analysis (IRFA) that examines
 the impact of the proposed rule on small
 entities along with regulatory
 alternatives that could reduce that
 impact. The IRFA is available for review
 in the docket and is summarized below.

 3. Initial Regulatory Flexibility Analysis
   As part of the 1996 amendments to
 the Safe Drinking Water Act  (SDWA),
 Congress required the U.S.
 Environmental Protection Agency (EPA)
 to develop a Long Term Stage 1
 Enhanced Surface Water Treatment Rule
 (LT1ESWTR) under Section
 1412(b)(2)(C) which focuses on surface
 water drinking water systems that serve
 fewer than 10,000 persons. Congress
 also required EPA to develop a      J
 companion Filter Backwash Recycle
 Rule (FBRR) under Section 1412(b)(14)
 which will require that all surface water
 public water systems, regardless of size,
 meet new requirements governing the
 recycle of filter backwash within the
 drinking water treatment process. The
 goal of both the LTlESWTR and the
 related FBRR is to provide additional
 protection from disease-causing
 microbial pathogens for community and
 non-community public water systems
 (PWSs) utilizing surface water.
  For purposes of assessing the impacts
 of today's rule on small entities, small
 entity is defined by systems serving
 fewer than 10,000 people. The small
 entities directly regulated by  this
 proposed rule are surface water and
 systems using ground water under the
 direct influence of surface water
 (GWUDI), using filtration and serving
 fewer than 10,000 people. We have
 determined that the final rule would
result in approximately 2,400 systems
 needing capital improvement to meet
the turbidity requirements,
 approximately 3,360 systems would
need to significantly change their

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disinfection practices, and
approximately 790 systems would need
to make capital improvements to change
the location of return of their filter
backwash recycle stream. A discussion
of the impacts on small entities is
described in more detail in chapters six
and seven of the Regulatory Impact
Analysis of the LT1FBR (EPA, 1999).
  The following recordkeeping and
reporting burdens were projected in the
IRFA:
Turbidity Monitoring and Reporting
Costs
  Utility monitoring activities at the
plant level include data collection, data
review, data reporting and monthly
reporting to the State. The labor burden
hours for data collection and review
were calculated under the assumption
that  plants are using on-line monitoring,
in the form of a SCADA or other
automated data collection system. The
data collection process requires that a
plant engineer gather and organize
turbidimeter readings from the SCADA
output and enter them into either a
spreadsheet or a log once per 8-hour
shift (three times per day).
  After data retrieval, the turbidity data
from each turbidimeter will be reviewed
by a plant engineer once per 8-hour shift
(three times per day) to ensure that the
filters are functioning properly and are
not displaying erratic or exceptional
patterns. A monthly summary data
report would be prepared. This task
involves the review of daily
spreadsheets and the compilation of a
summary report. It is assumed to take
one  employee 8 hours per month to
prepare. Recordkeeping  is expected to
take 5 hours per month.  Recordkeeping
entails organizing daily monitoring
spreadsheets and monthly summary
reports.
   Plant-level data will also be reviewed
monthly at the system level to ensure
that each plant in a system is in
compliance with the rule. A system-
level manager or technical worker will
review the daily monitoring
spreadsheets and monthly summary
reports that are generated at the plant
level. This task is estimated to take
about 4 hours per month. Once the
plant-level data have been reviewed, the
system manager or technical worker will
also compile a monthly system
summary report. These reports are
estimated to take 4 hours each month to
prepare.
Disinfection Benchmarking Monitoring
and Reporting Costs
   It is assumed that all Subpart H
systems currently collect the daily
inactivation data required to generate a
disinfection profile, in either an
electronic or paper format, and therefore
would not incur additional data
collection expenses due to microbial
profiling. Costs per plant are divided
into costs per plant using paper data,
costs per plant using mainframe data
and costs per plant using PC data. Plants
with paper  data were assumed to
represent half of the number of plants
needing benchmarking, while plants
with mainframe and plants with PC data
each represent a quarter.
Filter Backwash Monitoring and
Reporting Costs
  The proposed requirements are as
follows: All subpart H systems,
regardless of size, that use conventional
rapid  granular filtration, and that return
spent filter  backwash, thickener
supernatant, or liquids from dewatering
process to submit a schematic diagram
to the State showing their intended
changes to  move the return location
above the point of primary coagulant
addition.
  All subpart H systems, regardless of
size, that use conventional rapid
granular filtration and employ 20 or
fewer filters during the highest
production month and that use direct
recycling, to perform a self assessment
of their recycle practice and report the
results to the State.
  All subpart H systems, regardless of
system size that use direct filtration
must submit a report of their recycling
practices to the State. The State would
then determine whether changes in
recycling practices were warranted.
  EPA believes that the skill level
required for compliance with all of the
above recordkeeping, reporting and
other compliance activities  are similar
or equivalent to the skill level required
to pass the  first level of operator
certification required by most States.

Relevant Federal Rules
  EPA has  issued a Stage 1
Disinfectants/Disinfection Byproducts
Rule (DBPR) along with an Interim
Enhanced Surface Water Treatment Rule
(IESWTR) in December 1998, as
required by the Safe Drinking Water Act
Amendments of 1996. EPA proposed
these rules in July 1994. The Stage 1
DBPR includes a THM MCL of 0.080
mg/L (reduced from the existing THM
MCL of 0.10 mg/L established in 1979)
and an MCL of 0.060 mg/L for five
haloacetic  acids  (another group of
chlorination) as well as MCLs for
chlorite (1.0 mg/L) and bromate (0.010
mg/L) byproducts. The Stage 1 DBPR
also finalized MRDLs for chlorine (4
mg/L as C12), chloramine (4 mg/L as C12)
and chlorine dioxide (0.8 mg/L as CICh).
  In addition, the Stage 1 DBPR
includes requirements for enhanced
coagulation to reduce the concentration
of TOG in the water and thereby reduce
DBF formation potential. The IESWTR
was proposed to improve control of
microbial pathogens and to control
potential risk trade-offs related to the
need to meet lower DBF levels under
the Stage 1 DBPR.
  None of these regulations duplicate,
overlap or conflict with this proposed
rule.
Significant Alternatives
  As a result of consultations during the
SBREFA process, and public meetings
held subsequently, EPA has developed
several alternative options to those
presented in the IRFA, and has selected
preferred alternatives for each of the
turbidity, disinfection benchmarking
and filter backwash recycle provisions.
These alternatives were developed
based on feedback from small system
operators and trade associations and are
designed to protect public health, while
minimizing the burden to small
systems. In summary, the proposed
turbidity requirements are structured to
require recordkeeping once a week as
opposed to daily which was written in
the IRFA; the proposed disinfection
profile requirements are structured to be
taken once per week, as opposed to
daily which was written in the IRFA;
and the filter backwash requirements
have been scaled back significantly from
those included in the IRFA, i.e. a ban on
recycle is no longer being considered,
nor are several treatment techniques
now being considered that were in the
IRFA prior to discussions with
stakeholders. The provisions being
proposed are: systems that recycle will
be required to return recycle flows prior
to the rapid mix unit; direct recycle
systems will need to perform a self
assessment to determine whether
capacity is exceeded during recycle
events, and States will determine
whether recycle practices need to be
changed based on the self-assessment;
and direct filtration systems will need to
report their recycle practices to the
State, which will determine whether
changes to recycle practices are
required,

4. Small Entity Outreach and Small
Business Advocacy Review Panel
  As required by section 609(b) of the
RFA, as amended by SBREFA, EPA also
conducted outreach to small entities
and convened a Small Business
Advocacy Review Panel to obtain advice
and recommendations of representatives
of the small entities that potentially
would be subject to the rule's

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requirements. The SBAR Panel
produced two final reports; one for the
LT1 provisions and the other for the
filter backwash provisions. Although
the LTl and filter backwash provisions
have since been combined into the same
rule, the projected economic impact of
the provisions have not significantly
changed, and the relevance of SERs'
comments has not been affected.
  The Agency invited 24 SERs to
participate in the SBREFA process, and
16 agreed to participate. The SERs were
provided with background information
on the Safe Drinking Water Act and the
LT1FBR in preparation for a
teleconference on April 28,1998. This
information package included data on
options as well as preliminary unit costs
for treatment enhancements under
consideration. Eight SERs provided
comments on these materials.
  On August 25,1998, EPA's Small
Business Advocacy Chair person
convened the Panel under section
609(b) of the Regulatory Flexibility Act
as amended by the Small Business
Regulatory Enforcement Fairness Act
(SBREFA). In addition to its
chairperson, the Panel consisted of the
Director of the Standards and Risk
Management Division of the Office of
Ground Water and Drinking Water
within EPA's Office of Water, the
Administrator of the Office of
Information and Regulatory Affairs
within the Office of Management and
Budget, and the Chief Counsel for
Advocacy of the Small Business
Administration. The SBAR Panels
reports, Final Report of the SBREFA
Small Business Advocacy Review Panel
on EPA's Planned Proposed Rule: Long
Term 1 Enhanced  Surface Water
Treatment (EPA, 1998k) and the Final
Report of the SBREFA Small Business
Advocacy Review Panel on EPA's
Planned Proposed Rule: Filter Backwash
Recycling (EPA, 19981), contain the
SERs comments on the components of
the LT1FBR.
  The SERs were provided with
additional information on potential
costs related to LTlFBR regulatory
options  during teleconferences on
September 22 and 25,1998. Nine SERs
provided additional comments during
the September 22 teleconference, four
SERs provided additional comments
during the September 25 teleconference,
and three SERs provided written
comment on these materials.
  In general, the SERs that were
consulted on the LTlFBR were
concerned about the impact of the
proposed rule on small water systems
(because of their small staff and limited
budgets), small systems' ability to
acquire the technical and financial
                    capability to implement requirements,
                    and maintaining flexibility to tailor
                    requirements to the needs and
                    limitations of small systems. Consistent
                    with the RFA/SBREFA requirements,
                    the Panel evaluated the assembled
                    materials and small-entity comments on
                    issues related to the elements of the
                    IRFA. The background information
                    provided to the SBAR Panel and the
                    SERs are available for review in the
                    water docket. A copy of the Panel report
                    is also included in the docket for this
                    proposed rule.  The Panel's
                    recommendations to address the SERs
                    concerns are described next.

                    a. Number of Small Entities Affected
                      When the IRFA was prepared, EPA
                    initially estimated that there were 5,165
                    small public water systems that use
                    surface water or GWUDI. A more
                    detailed discussion of the impact of the
                    proposed rule and the number of
                    entities  affected is found in Section VI.
                    None of the commenters  questioned the
                    information provided by  EPA on the
                    number and types of small entities
                    which may be impacted by the LTlFBR.
                    This information is based upon the
                    national Safe Drinking Water
                    Information System (SDWIS) database,
                    which contains data on all public •water
                    systems in the country. The Panel
                    believed this was a reasonable data
                    source to characterize the number and
                    types of systems impacted by the
                    proposed rule.
                    b. Recordkeeping and Reporting
                      The Panel noted that some small
                    systems are operated by a sole, part time
                    operator with many duties beyond
                    operating and maintaining the drinking
                    •water treatment system and that several
                    components of the proposed rule may
                    require significant additional operator
                    time to implement. These included
                    disinfection profiling, individual filter
                    monitoring, and ensuring that short-
                    term turbidity spikes are corrected
                    quickly.
                      One SER stated that assumptions can
                    be made that small systems will have to
                    add an additional person to comply
                    with the monitoring and recordkeeping
                    portions of the rule. Another SER
                    commented that the most viable and
                    economical option would be to use
                    circuit riders (a trained operator who
                    travels between plants) to fill staffing
                    needs, but the LTlFBR would increase
                    the amount of time that a circuit rider
                    would be required to spend at each
                    plant. An additional option
                    recommended by several  SERs to reduce
                    monitoring burden and cost was to
                    allow the use of one on-line
                    turbidimeter to measure several filters.
This would entail less frequent
monitoring of each filter but might still
be adequate to ensure that individual
filter performance is maintained.
  The proposed LTlFBR takes into
consideration the recordkeeping and
reporting concerns identified by the
Panel and the SERs. For example,
initially the Agency considered
requiring systems to develop a profile of
individual filter performance. Based on
concerns from the SERs this
requirement was eliminated. In
addition, the Agency initially
considered requiring  operators to record
pH, temperature, residual chlorine and
peak hourly flow every day. This
requirement has been scaled back to
once per week to meet difficulties faced
by small system operators. Finally, in
today's proposed rule the Agency is
requesting comment on a modification
to allow one on-line turbidimeter
instead  of several to be used at the
smallest size  systems (systems serving
fewer than 100 people).

c. Interaction With Other Federal Rules
  The Panel noted that the LTlFBR and
Stage 1 DBF rules will affect small
systems virtually simultaneously and
that the Agency should analyze the net
impact of these rules  and consider
regulatory options that would minimize
the impact on small systems.
  One SER commented that any added
responsibility or workload due to
regulations will have  to be absorbed by
him and his staff. He  noted that many
systems, including his own, are losing
staff through attrition and are unable to
hire replacements. The SER stated that
he hoped the Panel was aware of the
volume  of rules and regulations to
which small systems are currently
subject.  As an example, the SER stated
that he had spent a week's time
collecting samples for the mandated
tests of the Lead and Copper rule. He
noted that the sampling had delayed
important maintenance to his system by
over a month.
  The Agency considered these
comments when developing the
requirements  of today's proposed rule,
and developed the alternatives with the
realization that small  systems will be
required to implement several rules in
a short time frame. In today's proposed
rule, the preferred options attempt to
minimize the impact on small systems
by reducing the amount of monitoring
and the amount of operator's time
necessary to collect and analyze data.
For example, under the IESWTR, large
systems  are required to monitor
disinfection byproducts for 1 year to
determine whether or not they must
develop  a disinfection profile (based on

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                                                                    19129
daily measurements of operating
conditions). In response to SERs
concerns, the Agency is proposing to
eliminate the requirement for
disinfection byproduct monitoring all
together. Under the proposed
requirements, all systems would
develop a disinfection profile based on
weekly measurements of operating
parameters for 1 year. Overall, this will
save small system operators both time
and money. The proposed rule also
requests comment on several additional
strategies for reducing impacts.
d. Significant Alternatives
  During the SBAR panel several
alternatives were discussed with the
Panel and SERs. These alternatives and
the Panel's recommendations are
discussed next.
5. Turbidity Provisions
  During the SBAR Panel, the Agency
presented the IESWTR turbidity
provisions as appropriate components
for the LT1FBR. The Panel noted that
one SER commented that it was a  fair
assumption that turbidity up to 1 NTU
maximum and 0.3 NTU in 95% of all
monthly samples is a good indicator of
two log removal of Cryptosporidium,
but stressed the need to allow operators
adequate time  to respond to
exceedances in automated systems.
They were referring to the fact the small
system operators are often away from
the plant performing other duties, and
cannot respond immediately if the
turbidity levels exceed a predetermined
level. The Panel recommended that EPA
consider this limitation when
developing reporting and recordkeeping
requirements.
  The Panel also noted that another SER
agreed that lowered turbidity level is a
good indicator of overall plant •
performance but thought the 0.3 NTU
limit for the 95th percentile reading was
too low in light of studies which appear
to show variability and inaccuracies in
low level turbidity measurements. This
SER referenced specific data suggesting
that current equipment used to measure
turbidity levels below the 0.3 NTU may
nonetheless give readings above 0.3
which would put the system out of
compliance. EPA has evaluated this
issue in the context  of the 1997 IESWTR
FACA negotiations and believes that
readings below the 0.3 NTU are reliable.
Moreover, EPA notes that the SERs'
concern was based on raw performance
evaluation  data that had not been fully
analyzed.
  Finally, the Panel recognized that
several SERs supported individual filter
monitoring, provided there was
flexibility for short duration turbidity
spikes. Other SERs, however, noted that
the assumption that individual filter
monitoring was necessary was
unreasonable. The Panel recommended
that EPA consider the likelihood and
significance of short duration spikes
(i.e., during the first 15-30 minutes of
filter operation) when evaluating the
frequency of individual filter
monitoring and reporting requirements
and the number and types of
exceedances that will trigger
requirements for Comprehensive
Performance Evaluations (CPEs). The
Panel also noted the concern expressed
by several SERs that individual filter
monitoring may not be practical or
feasible in all situations.
  The Agency has structured today's
proposed rule with an emphasis on
providing flexibility for small systems.
The individual filter provisions have
been tailored to be easier to understand
and implement and require less data
analysis. For example, the operator can
look at monitoring data once per week
under this rule, as opposed to having to
review turbidity data every day as the
larger systems are required to do. The
proposed rule also requests comment on
several modifications to provide
additional flexibility to small systems.

ii. Disinfection Benchmarking:
Applicability Monitoring Provisions
  None of the SERs commented
specifically on the applicability
monitoring provisions which are
designed to identify systems tiiat may
consider cutting back on their
disinfection doses in order to avoid
problems with disinfection byproducts
formation. The Panel noted, however,
that burden on small systems might be
reduced if alternative applicability
monitoring provisions were adopted. In
consideration of the Panel's suggestions,
the Agency first considered  limiting the
applicability monitoring, and has now
eliminated this requirement from the
proposal. It is optional, however, for
systems who believe their disinfection
byproduct levels are below 80% of the
MCL—as required under the Stage 1
DBPR.
  The Panel noted SER comments that
monitoring and computing Giardia
lamblia inactivation on a daily basis for
a year would place a heavy burden on
operators that may only staff the plant
for a few hours per day. The Panel
therefore recommended that EPA
consider alternative profiling strategies
which ensure adequate public health
protection, but will minimize
monitoring and recordkeeping
requirements for small system operators.
  The Agency considered several
alternatives to the profile development
strategies, and decided to propose that
systems perform the necessary
monitoring and record the results once
per week, instead of every day as the
larger systems are required to do. This
will significantly reduce burden and
costs for small systems.

iii. Recycling Provisions
  During the SBAR Panel, the Agency
proposed several alternatives for
consideration in the LT1FBR including
a ban on recycle, a requirement to return
recycle flow to the head of the plant,
recycle flow equalization, and recycle
flow treatment. The Panel noted the
concern of the SERs regarding a ban on
the recycle of filter backwash water.
These concerns included the expense of
filter backwash disposal and the
economic and operational concerns of
western and southwestern drinking
water systems which depend on
recycled flow to maintain adequate
supply. The Panel strongly
recommended that EPA explore
alternatives to an outright ban on the
recycle of filter backwash and other
recycle flows.
  The Panel noted that SERs supported
a requirement that all recycled water be
reintroduced at the head of the plant.
This was considered an element of
sound engineering practice. The Panel
recommended that EPA consider
including such a requirement in the
proposed rule, and investigate whether
there are small systems for which such
a requirement would present a
significant financial and operational
burden.
  The Panel noted that SERs agreed
with the appropriateness of flow
equalization for filter backwash. The
Panel supported the concept of flow
equalization as a means to minimize
hydraulic surges that may be caused by
recycle and the reintroduction of a large
number of Cryptosporidium oocysts or
other pathogenic contaminants to the
plant in a brief period of time. The
Panel noted that there are various ways
of achieving flow equalization and
suggested that specific requirements
remain flexible.
  The Panel noted the concerns of SERs
regarding installation of treatment,
solely for the purpose of treating filter
backwash water and/or recycle streams
may be costly and potentially
prohibitive for small systems. The
Agency addressed this concern by
allowing the States to determine
whether recycle flow equalization or
treatment is necessary based on the
results of the self assessment prepared
by the S3fstem rather than requiring
universal flow equalization or
treatment. This will allow site-specific

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factors to be considered and help
minimize cost and burden.

e. Other Comments
  The Panel also noted the concern of
several SERs that flexibility be provided
in the compliance schedule of the rule.
SERs noted the technical and financial
limitations that some small systems will
have to address, the significant learning
curve for operators with limited
experience, and the need to continue
providing uninterrupted service  as
reasons why additional compliance time
may be needed for small systems. The
panel encouraged EPA to keep these
limitations in mind in developing the
proposed rule and provide as much
compliance flexibility to small systems
as is allowable under the SDWA. We
invite comments on all aspects of the
proposal and its impacts on small
entities.
  The Agency structured the timing of
the LT1ESWTR provisions specifically
to follow the promulgation of the
IESWTR. Since the IESWTR served as a
template for the establishment of the
LTlESWTR provisions, the Agency
decided that small systems would have
an advantage by giving them an
opportunity to see what was in the rule,
and how it was implemented by  larger
systems.
  Under SDWA, systems have 3  years to
comply with the requirements of the
final rule. If capital improvements are
necessary for a particular PWS, a State
may allow the system up to an
additional 2 years to comply with the
regulation. The Agency is developing
guidance manuals to assist the
compliance efforts of small entities.
B. Paperwork Reduction Act
  The information collection
requirements in this proposed rule have
been submitted for approval to the
Office of Management and Budget
(OMB) under the Paperwork Reduction
Act, 44 U.S.C. 3501 et seq. An
Information Collection Request (ICR)
document has been prepared by EPA
(ICR No. 1928.01) and a copy may be
obtained from Sandy Farmer by mail at
OP  Regulatory Information Division;
U.S. Environmental Protection Agency
(2137); 401 M St., S.W.; Washington,  DC
20460, by email at
farmer.sandy@epamail.epa.gov, or by
calling (202) 260-2740. A copy may also
be downloaded off the Internet at http:/
lwww.epa.gov/icr. For technical
information about the collection  contact
Jini Mohanty by calling (202) 260-6415.
  The information collected as a result
of this rule will allow the States and
EPA to determine appropriate
requirements for specific systems, in
                     some cases, arid to evaluate compliance
                     with the rule. For the first three years
                     after the effective date (six years after
                     promulgation) of the LT1FBR, the major
                     information requirements are (1)
                     monitor filter performance and submit
                     any exceedances of turbidity
                     requirements (/.e. exceptions reports) to
                     the State; (2) develop a 1 month recycle
                     monitoring plan and submit both plan
                     and results to the State; (3) submit flow
                     monitoring plan and results to the State;
                     and (4) report data on current recycle
                     treatment (self assessment) to the State.
                     The information collection requirements
                     in Part 141,  for systems, and Part 142,
                     for States are mandatory.  The
                     information collected is not
                     confidential.
                      Burden means the total time, effort, or
                     financial resources expended by persons
                     to generate,  maintain, retain, or disclose
                     or provide information to or for a
                     Federal Agency. This includes the time
                     needed to review instructions; develop,
                     acquire, install, and utilize technology
                     and systems for the purposes of
                     collecting, validating, and verifying
                     information, processing and
                     maintaining information, and disclosing
                     and providing information; adjust the
                     existing ways to comply with any
                     previously applicable instructions and
                     requirements; train personnel to be able
                     to respond to a collection of
                     information; search data sources;
                     complete and review the collection of
                     information; and transmit or otherwise
                     disclose the information.
                      The preliminary estimate of aggregate
                     annual average burden hours for
                     LTlFBR is 311,486. Annual average
                     aggregate cost estimate is  $10,826,919
                     for labor, $2,713,815 for capital, and
                     $1,898,595 for operation and
                     maintenance including lab costs which
                     is a purchase of service. The burden
                     hours per response is 18.9. The
                     frequency of response (average
                     responses per respondent) is 2.7
                     annually. The estimated number of
                     likely respondents is 6,019 (the product
                     of burden hours per response,
                     frequency, and respondents does not
                     total the annual average burden hours
                     due  to rounding). Most of the regulatory
                     provisions discussed in this notice
                     entail new reporting and recordkeeping
                     requirements for States, Tribes, and
                     members of the regulated public.  An
                     Agency may not conduct  or sponsor,
                     and  a person is not required to respond
                     to a  collection of information unless it
                     displays a currently valid OMB control
                     number. The OMB control numbers for
                     EPA's regulations are listed in 40 CFR
                     Part 9 and 48 CFR Chapter 15.
                      Comments are requested on the
                     Agency's need for this information, the
accuracy of the provided burden
estimates, and any suggested methods
for minimizing respondent burden,
including through the use of automated
collection techniques. Send comments
on the ICR to the Director, OP
Regulatory Information Division; U.S.
Environmental Protection Agency
(2137); 401 M St., S.W.; Washington, DC
20460; and to the Office of Information
and Regulatory Affairs, Office of
Management and Budget, 725 17th St.,
N.W., Washington, DC 20503, marked
"Attention: Desk Officer for EPA."
Include the ICR number in any
correspondence. Since OMB is required
to make a decision concerning the ICR
between 30 and 60 days after April 10,
2000, a comment to OMB is best assured
of having its full effect if OMB receives
it by May 10, 2000. The final rule will
respond to any OMB or public
comments on the information collection
requirements contained in this proposal.

C. Unfunded Mandates Reform Act

1. Summary of UMRA requirements
  Title II of the Unfunded Mandates
Reform Act of  1995 (UMRA), Public
Law 104-4, establishes requirements for
Federal agencies to assess the effects  of
their regulatory actions on State, local,
and tribal governments and the private
sector. Under UMRA section 202, EPA
generally must prepare a written
statement, including a cost-benefit
analysis, for proposed and final rules
with "Federal mandates" that may
result in expenditures by State, local,
and tribal governments, in the aggregate,
or to the private sector, of $100 million
or more in any one year. Before
promulgating an EPA rule, for which a
written statement is needed, section 205
of the UMRA generally requires EPA  to
identify and consider a reasonable
number of regulatory alternatives and
adopt the least costly, most cost-
effective or least burdensome alternative
that achieves the objectives of the rule.
The provisions of section 205 do not
apply when they are inconsistent with
applicable law. Moreover, section 205
allows EPA to adopt an alternative other
than the least costly, most cost effective
or least burdensome alternative if the
Administrator publishes with the final
rule an explanation why that alternative
was not adopted.
  Before EPA establishes any regulatory
requirements that may significantly or
uniquely affect small governments,
including tribal governments, it must
have developed, under section 203 of
the UMRA, a small government agency
plan. The plan must provide for
notification to potentially affected small
governments, enabling officials of

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affected small governments to have
meaningful and timely input in the
development of EPA regulatory
proposals with significant Federal
intergovernmental mandates and
informing, educating, and advising
small governments on compliance with
the regulatory requirements.
2. Written Statement for Rules With
Federal Mandates of $100 Million or
More
  EPA has determined that this rule
does not contain a Federal mandate that
may result in expenditures of $100
million or more for the State, local and
Tribal governments, in the aggregate, or
the private sector in any one year. Thus
today's rule is not subject to the
requirements of sections 202 and 205 of
the UMRA. Nevertheless, since the
estimate of annual impact is close to
SlOO million under certain assumptions
EPA has prepared a written statement,
which is summarized below, even
though one is not required. A more
detailed description of this analysis is
presented in EPA's Regulatory Impact
Analysis of the LTlFBR (EPA, 1999h)
which is available for public review in
the Office of Water docket under docket
number W-99-10. The document is
available for inspection from 9 a.m. to
4 p.m., Monday through Friday,
excluding legal holidays. The docket is
located in room EB 57, USEPA
Headquarters, 401 M St. SW,
Washington, D.C. 20460. For access to
docket materials, please call  (202) 260-
3027 to schedule an appointment.
a. Authorizing Legislation
  Today's rule is proposed pursuant to
Section 1412 (b)(2)(C) and 1412(b)(14) of
the SDWA. Section 1412 (b)(2)(C)
directs EPA to establish a series of
regulations including an interim and
final enhanced surface water treatment
rule. Section 1412(b)(14) directs EPA to
promulgate a regulation to govern the
recycling of filter backwash water. EPA
intends to finalize the LTlFBR in the
year 2000 to allow systems to consider
the dual impact of this rule and the
Stage 1 DBF rule on their capital
investment decisions.
b. Cost Benefit Analysis
  Section VI of this preamble discusses
the cost and benefits associated with the
LTlFBR. Also, the EPA's Regulatory
Impact Analysis of the LTlFBR (EPA,
1999h) contains a detailed cost benefit
analysis. Today's proposal is expected
to have a total annualized cost of
approximately $ 97.5 million using a 7
percent discount rate. At a 3 percent
discount rate the annualized costs drop
to $87.6 million. The national cost
 estimate includes cost for all of the
 rule's major provisions including
 turbidity monitoring, disinfection
 benchmarking monitoring, disinfection
 profiling, covered finished storage, and
 recycling. The majority of the costs for
 this rule will be incurred by the public
 sector. A more detailed discussion of
 these costs is located in Section VI of
 this preamble.
   In addition, the regulatory impact
 analysis includes both monetized
 benefits and descriptions of
 unquantified benefits for improvements
 to public health and safety the rule will
 achieve. Because of scientific
 uncertainty regarding LTlFBR's
 exposure and risk assessment, the
 Agency has used Monte Carlo methods
 and sensitivity analysis to assess the
 quantified benefits of today's rule. The
 monetary analysis was based upon
 quantification of the number of
 cryptosporidiosis illnesses avoided due
 to improved particulate removal that
 results from the turbidity provisions.
 The Agency was not able to monetize
 the benefits from the other rule
 provisions such as disinfection
 benchmarking and covered finished
 storage. The monetized annual benefits
 of today's rule range from $70.1 million
 to $259.4 million depending on the
^baseline and removal assumptions.
 Better management of recycle streams
 required by the proposal also result in
 nonquantifiable health risk reductions
 from disinfection resistant pathogens.
 The rule may also decrease illness
 caused by Giardia and other emerging
 disinfection resistant pathogens, further
 increasing the benefits.
   Several non-health benefits from this
 rule were also identified by EPA but
 were not monetized. The non-health
 benefits of this rule include outbreak
 response costs avoided, and possibly
 reduced uncertainty and averting
 behavior costs. By adding the non-
 monetized benefits with those that are
 monetized,  the overall benefits of this
 rule increase beyond the dollar values
 reported.
   Various Federal programs exist to
 provide financial assistance to State,
 local, and Tribal governments in
 complying with this rule. The Federal
 government provides funding to States
 that have primary enforcement
 responsibility for their drinking water
 programs through the Public Water
 Systems Supervision Grants program.
 Additional funding is available from
 other programs administered either by
 EPA, or other Federal Agencies. These
 include EPA's Drinking Water State
 Revolving Fund (DWSRF), U.S.
 Department of Agriculture's Rural
 Utilities' Loan and Grant Program, and
Housing and Urban Development's
Community Development Block Grant
Program.
  For example, SDWA authorizes the
Administrator of the EPA to award
capitalization grants to States, which in
turn can provide low cost loans and
other types of assistance to eligible
public water systems. The DWSRF helps
public water systems finance the cost of
infrastructure necessary to achieve or
maintain compliance with SDWA
requirements. Each State has
considerable flexibility to design its
program and to direct funding toward
the most pressing compliance and
public health protection needs. States
may also, on a matching basis, use up
to ten percent of their DWSRF
allotments each fiscal year to run the
State drinking water program.
  Furthermore, a State can use the
financial resources of the DWSRF to
assist small systems. In fact, a minimum
of 15% of a State's DWSRF grant must  ,
be used to provide infrastructure loans
to small systems. Two percent of the
State's grant may be used to provide
technical assistance to small systems.
For small systems that are   .
disadvantaged, up to 30% of a State's
DWSRF may be used for increased loan
subsidies. Under the DWSRF, Tribes   ;
have a separate set-aside which they can
use. In addition to the DWSRF, money
is available from the Department of
Agriculture's Rural Utility Service
(RUS) and Housing and Urban
Development's Community Block Grant
(CDBG) program. RUS provided-loans,
guaranteed loans, and grants to improve,
repair, or construct water supply and
distribution systems in rural areas and
towns up to 10,000 people. In fiscal year
1997, the RUS had over $1.3 billion in
available funds. Also, three sources of
funding exist under the CDBG program
to finance building and improvements ,
of public faculties such as water
systems. The three sources of funding
include: (1) Direct grants to
communities with populations over
200,000; (2) direct grants to States,
which they in turn award to smaller
communities, rural areas, and colonias
in Arizona, California, New Mexico, and
Texas; and (3) direct grants to US.
Territories and Trusts. The CDBG
budget for fiscal year 1997 totaled over
$4 billion dollars.
c. Estimates of Future Compliance Costs;
and Disproportionate Budgetary Effects
  To meet the UMRA requirement in
section 202, EPA analyzed future
compliance costs and possible
disproportionate budgetary effects. The
Agency believes that the cost estimates,
indicated previously and discussed in

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more detail in Section VI of this
preamble, accurately characterize future
compliance costs.
  In analyzing the disproportionate
impacts, EPA considered four measures:
  (l) The impacts of small versus large
systems and the impacts within the five
small system size categories;
  (2) The costs to public versus private
water systems;
  (3) The costs to households, and;
  (4) The distribution of costs across
States.
  First, small systems will experience a
greater impact than large systems under
LT1FBR because large systems are
subject only to the recycle provisions.
The Interim Enhanced Surface Water
Treatment Rule (IESWTR) promulgated
turbidity, benchmarking, and covered
finished storage provisions for large
systems in December, 1998. However,
small systems have realized cost savings
over time due to their exclusion from
the IESWTR. Also, some provisions in
the LT1FBR have been modified so they
would not be as burdensome for small
systems. Further information on these
changes can be found in section
VII.A.3.of this proposal.
  The second measure of impact is the
relative total cost to privately owned
water systems compared to the incurred
by publicly owned water systems. A
majority of the systems are publicly
owned (60 percent of the total]. As a
result, publicly owned systems will
incur a larger share of the total costs of
the rule.
  The third measure, household costs,
is described in further detail in VLB of
this preamble. The fourth measure,
distribution of costs across States, is
described in greater detail in the RIA for
today's proposed rule (EPA, 1999h).
There is nothing to suggest that costs to
individual systems would vary
significantly from State to State, but as
expected, the States with the greatest
number of systems experience the
greatest costs.
d. Macro-Economic Effects
  As required under UMRA Section
202, EPA is required to estimate the
potential macro-economic effects of the
regulation. These types of effects
include those on productivity, economic
growth, full employment, creation of
productive jobs, and international
competitiveness.  Macro-economic
effects tend to be measurable in
nationwide econometric models only if
the economic impact of the regulation
reaches 0.25 percent to 0.5 percent of
Gross Domestic Product (GDP). In 1998,
real GDP was $7,552 billion. This
proposal would have to cost at least $18
billion to have a measurable effect. A
                     regulation of less cost is unlikely to
                     have any measurable effect unless it is
                     highly focused on a particular
                     geographic region or economic sector.
                     The macro-economic effects on the
                     national economy from LTlFBR should
                     not have a measurable effect because the
                     total annual cost of the preferred option
                     is approximately $ 97.5 million per year
                     (at a seven percent discount rate). The
                     costs are not expected to be highly
                     focused on a particular geographic
                     region or sector.
                     e. Summary of EPA's Consultation with
                     State, Local, and Tribal Governments
                     and Their Concerns
                       Consistent with the intergovernmental
                     consultation provisions of section 204 of
                     UMRA EPA has already initiated
                     consultation with the governmental
                     entities affected by this rule.
                       EPA began outreach efforts to develop
                     the LTlFBR in the summer of 1998.
                     Two public stakeholder meetings,
                     which were announced in the Federal
                     Register, were held on July 22-23, 1998,
                     in Lakewood, Colorado, and on March
                     3-4,1999, in Dallas, Texas. In addition
                     to these meetings, EPA has held several
                     formal and informal meetings with
                     stakeholders including the Association
                     of State Drinking Water Administrators.
                     A summary of each meeting and
                     attendees is available in the public
                     docket for this rule. EPA also convened
                     a Small Business Advocacy Review
                     (SBAR) Panel in accordance with the
                     Regulatory Flexibility Act (RFA), as
                     amended by the Small Business
                     Regulatory Enforcement Fairness Act
                     (SBREFA) to address small entity
                     concerns including those of small local
                     governments. The SBAR Panel allows
                     small regulated entities to provide input
                     to EPA early in the regulatory
                     development process.  In early June,
                     1999, EPA mailed an informal draft of
                     the LTlFBR preamble to the
                     approximately 100 stakeholders who
                     attended one of the public stakeholder
                     meetings. Members of trade associations
                     and the SBREFA Panel also received the
                     draft preamble. EPA received valuable
                     comments and stakeholder input from
                     15 State representatives, trade
                     associations, environmental interest
                     groups, and individual stakeholders.
                     The majority of concerns dealt with
                     reducing burden on small systems and
                     maintaining flexibility. After receipt of
                     comments, EPA  made every effort to
                     make modifications to address these
                     concerns.
                       To inform and involve Tribal
                     governments in the rulemaking process,
                     EPA presented the LTlFBR at three
                     venues: the 16th Annual Consumer
                     Conference of the National Indian
Health Board, the annual conference of
the National Tribal Environmental
Council, and the OGWDW/Inter Tribal
Council of Arizona, Inc. tribal
consultation meeting. Over 900
attendees representing tribes from
across the country attended the National
Indian Health Board's Consumer
Conference and over 100 tribes were
represented at the annual conference of
the National Tribal Environmental
Council. At both conferences, an
OGWDW representative conducted two
workshops on EPA's drinking water
program and upcoming regulations,
including the LTlFBR.
  At the OGWDW/Inter Tribal Council
of Arizona meeting, representatives
from 15 tribes participated. The
presentation materials and meeting
summary were sent to over 500 tribes
and tribal organizations. Additionally,
EPA contacted each of our 12 Native
American Drinking Water State
Revolving Fund Advisors to invite
them, and representatives of their
organizations to the stakeholder
meetings described previously. A list of
tribal representatives contacted can be
found in the docket for this rule.
  The primary concern expressed by
State, local and Tribal governments is
the difficulty the smallest systems will
encounter in adequately staffing
drinking water treatment facilities to
perform the monitoring and reporting
associated with the new requirements.
Today's proposal attempts  to minimize
the monitoring and reporting burden to
the greatest extent feasible  and still
accomplish the rule's objective of
protecting public health. The Agency
believes the monitoring and reporting
requirements are necessary to ensure
consumers served by small systems
receive the same level of public health
protection as consumers served by large
systems.  Summaries of the  meetings
have been included in the public docket
for this rulemaking.

f. Regulatory Alternatives Considered

  As required under Section 205 of the
UMRA, EPA considered several
regulatory alternatives for individual
filter monitoring and disinfection
benchmarking, as well as several
alternative strategies for addressing
recycle practices. A detailed discussion
of these alternatives can be found in
Section IV and also in the RIA for
today's proposed rule (EPA, 1999h).
Today's proposal also seeks comment
on several regulatory alternatives that
EPA will consider for the final rule.

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g. Selection of the Least Costly, Most-
Cost Effective or Least Burdensome
Alternative That Achieves the
Objectives of the Rule
  As discussed previously, EPA has
considered and requested comment on
various regulatory options that would
reduce Cryptosporidium occurrence in
the finished water of surface water
systems. The Agency believes that the
preferred option for turbidity
performance, disinfection
benchmarking, and recycle management
are the most cost effective combination
of options to achieve the rule's
objective; the reduction of illness and
death from Cryptosporidium occurrence
in the finished water of PWSs using
surface water. The Agency will carefully
review comments on the proposal and
assess suggested changes to the
requirements.
3. Impacts on Small Governments
  In developing this proposal, EPA
consulted with small governments to
address impacts of regulatory
requirements in the rule that might
significantly or uniquely affect small
governments. As discussed previously, a
variety of stakeholders, including small
governments, were provided the
opportunity for timely and meaningful
participation in the regulatory
development process through the
SBREFA panel, public stakeholder and
Tribal meetings. EPA used these
processes to notify potentially affected
small governments of regulatory
requirements being considered and
provided officials of affected small
governments with an opportunity to
have meaningful and timely input to the
regulatory development process.
  In addition, EPA will educate, inform,
and advise small systems, including
those run by small governments, about
LTlFBR requirements. One of the most
important components of this outreach
effort will be the Small Entity
Compliance Guide, required by the
Small Business Regulatory Enforcement
Fairness Act of 1996. This plain-English
guide will explain what actions a  small
entity must take to comply with the
rule. Also, the Agency is developing fact
sheets that concisely describe various
aspects and requirements of the LTlFBR
and detailed guidance manuals to assist
the compliance effort of PWSs and small
government entities.
D. National Technology Transfer and
Advancement Act
  Section 12(d) of the National
Technology Transfer and Advancement
Act of 1995 (NTAA), Public Law No.
104-113, section 12(d) (15 U.S.C.  272
note), directs EPA to use voluntary
consensus standards in its regulatory
activities unless to do so would be
inconsistent with applicable law or
otherwise impractical. Voluntary
consensus standards are technical
standards (e.g., materials specifications,
test methods, sampling procedures,
business practices) that are developed or
adopted by voluntary consensus
standards bodies. The NTAA directs
EPA to provide Congress, through the
Office of Management and Budget,
explanations when the Agency decides
not to use available and applicable
voluntary consensus standards.
  Today's rule requires the use of
previously approved technical
standards for the measurement of
turbidity. In previous rulemakings, EPA
approved three methods for measuring
turbidity in drinking water. These can
be found in 40 CFR,  Part 141.74 (a).
Turbidity is a method-defined
parameter and therefore modifications
to any of the three approved methods
requires prior EPA approval. One of the
approved methods was published by the
Standard Methods Committee of
American Public Health Association,
the American Water Works Association,
and the Water Environment Federation,
the latter being a voluntary consensus
standard body. That method, Method
2130B (APHA, 1995), is published in
Standard Methods for the Examination
of Water and Wastewater (19th ed.).
Standard Methods is a widely used
reference which has been peer-reviewed
by the scientific community. In addition
to this voluntary consensus standard,
EPA approved two additional methods
for the measurement of turbidity. One is
the Great Lakes Instrument Method 2,
which can be used as an alternate test
procedure for the measurement of
turbidity (Great Lakes Instruments,
1992). Second, the Agency approved
revised EPA Method 180.1 for turbidity
measurement in August 1993 in
Methods for the Determination of
Inorganic Substances in Environmental
Samples (EPA-600/R-93-100) (EPA,
1993).
  In 1994, EPA reviewed and rejected
an additional technical standard, a
voluntary consensus standard, for the
measurement of turbidity, die ISO 7027
standard, an analytical method which
measures turbidity at a higher
wavelength than the approved test
measurement standards. ISO 7027
measures turbidity using either 90°
scattered or transmitted light depending
on the turbidity concentration
evaluated. Although instruments
conforming to ISO 7027 specifications
are similar to the GLI instrument, only
the GLI instrument uses pulsed,
multiple detectors to simultaneously
read both 90° scattered and transmitted
light. EPA has no data upon which to
evaluate whether the separate 90°
scattered or transmitted light
measurement evaluations, according to
the ISO 7027 method, would produce
results that are equivalent to results
produced using GLI Method 2, Standard
Method 2130B (APHA, 1995), or EPA
Method 180.1 (EPA, 1993).
  Today's proposed rule also requires
continuous individual filter monitoring
for turbidity and requires PWSs to
calibrate the individual turbidimeter
according to the turbidimeter
manufacturer's instructions. These
calibration instructions may constitute
technical standards as that term is
defined in the NTTAA. EPA has  looked
for voluntary consensus standards with
regard to calibration of turbidimeters.
The American Society for Testing and
Materials (ASTM) is developing such
voluntary consensus standards,
however, there do not appear to be any
voluntary consensus standards available
at this time. EPA welcomes comments
on this aspect of the proposed
rulemaking and, specifically invites the
public to identify potentially applicable
voluntary consensus standards and to
explain why such standards should be
used in this regulation.
  EPA plans to implement in the future
a performance-based measurement
system (PBMS) that would allow the
option of using either performance
criteria or reference methods in its
drinking water regulatory programs. The
Agency is currently determining the
specific steps necessary to implement
PBMS in its programs and preparing an
implementation plan. Final decisions
have not yet been made concerning the
implementation of PBMS in water
programs. However, EPA is currently
evaluating what relevant performance
characteristics should be specified for
monitoring methods used in the water
programs under a PBMS approach to
ensure adequate data quality. EPA
would then specify performance
requirements in its regulations to ensure
that any method used for determination
of a regulated analyte is at least
equivalent to the performance achieved
by other currently approved methods.
  Once EPA has made its final
determinations regarding
implementation of PBMS in programs
under the Safe Drinking Water Act, EPA
would incorporate specific provisions of
PBMS into its regulations, which may
include specification of the performance
characteristics for measurement of
regulated contaminants in the drinking
water program regulations.

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E. Executive Order 12866: Regulatory
Planning and Review
  Under Executive Order 12866, (58 FR
51735 (October 4, 1993) the Agency
must determine whether the regulatory
action is "significant" and therefore
subject to OMB review and the
requirements of the Executive Order.
The Order defines "significant
regulatory action" as one that is likely
to result in a rule that  may:
  1. Have an annual effect on the
economy of $100 million or more or
adversely affect in a material way the
economy, a sector of the economy,
productivity, competition, jobs, the
environment, public health or safety, or
State, local, tribal governments or
communities;
  2. Create a serious inconsistency or
otherwise interfere with an action taken
or planned by another agency;
  3. Materially  alter the budgetary
impact of entitlement, grants, user fees,
or loan programs or the rights and
obligations of recipients thereof, or;
  4. Raise novel legal  or policy issues
arising out  of legal mandates, the
President's priorities,  or the principles
set forth in the Executive Order.
  Pursuant to the terms of Executive
Order 12866, it has been determined
that this rule is  a "significant regulatory
action." As such, this  action was
submitted to OMB for  review. Changes
made in response to OMB suggestions or
recommendations will be documented
in the public record.

F. Executive Order 12898:
Environmental Justice
  Executive Order 12898 establishes a
Federal policy for incorporating
environmental justice  into Federal
agency missions by directing agencies to
identify and address disproportionately
high and adverse human health or
environmental effects  of its programs,
policies, and activities on minority and
low-income populations. The Agency
has considered  environmental justice
related issues concerning the potential
impacts of this action  and consulted
with minority and low-income
stakeholders.
  This preamble has discussed many
times how the IESWTR served as a
template for the development of the
LTlFBR. As such, the  Agency also built
on the efforts conducted during the
lESWTRs development to comply with
E.O. 12898. On  March 12,1998, the
Agency held a stakeholder meeting to
address various components of pending
drinking water regulations and how
they may impact sensitive sub-
populations, minority  populations, and
low-income populations. Topics
                     discussed included treatment
                     techniques, costs and benefits, data
                     quality, health effects, and the
                     regulatory process. Participants
                     included national, State, tribal,
                     municipal, and individual stakeholders.
                     EPA conducted the meetings by video
                     conference call between eleven cities.
                     This meeting was a continuation of
                     stakeholder meetings that started in
                     1995 to obtain input on the Agency's
                     Drinking Water Programs. The major
                     objectives for the March 12,1998
                     meeting were:
                       (1) Solicit ideas from stakeholders on
                     known issues concerning current
                     drinking water regulatory efforts;
                       (2) Identify key issues of concern to
                     stakeholders, and;
                       (3) Receive suggestions from
                     stakeholders concerning ways to
                     increase representation of communities
                     in OGWDW regulatory efforts.
                       In addition, EPA developed a plain-
                     English guide specifically for this
                     meeting to assist stakeholders in
                     understanding the multiple and
                     sometimes complex issues surrounding
                     drinking water regulation.
                       The LTlFBR applies to community
                     water systems, non-transient non-
                     community water systems, and transient
                     non-community water systems that use
                     surface water or ground water under the
                     direct influence (GWUDI) as their
                     source water for PWSs serving less than
                     10,000 people. The recycle provisions
                     apply to all conventional and direct
                     surface water or GWUDI systems
                     regardless of size.
                       EPA believes this rule will provide
                     equal health protection for all minority
                     and low-income populations served by
                     systems regulated under this rule from
                     exposure to microbial contamination.
                     These requirements will also be
                     consistent with the protection already
                     afforded to people being served by
                     systems with larger population bases.

                     G. Executive Order 13045Protection of
                     Children from Environmental Health
                     Risks and Safety Risks
                       Executive Order 13045: "Protection of
                     Children from  Environmental Health
                     Risks and Safety Risks" (62 FR 19885,
                     April 23,1997) applies to any rule that:
                     1) is determined to be economically
                     significant as defined under E.O. 12866,
                     and; 2)  concerns an environmental
                     health or safety risk that EPA has reason
                     to believe may have a disproportionate
                     effect on children. If the regulatory
                     action meets both criteria, the Agency
                     must evaluate the environmental health
                     or safety effects of the planned rule on
                     children and explain why the planned
                     regulation is preferable to other
                     potentially effective and reasonably
feasible alternatives considered by the
Agency.
  While this proposed rule is not
subject to the Executive Order because
it is not economically significant as
defined by E.O. 12866, we nonetheless
have reason to believe that the
environmental health or safety risk
addressed by this action may have a
disproportionate effect on children.
Accordingly, EPA evaluated available
data on the health effect of
Cryptosporidium  on children. The
results of this evaluation are contained
in Section II.B of this preamble and in
the LTlFBR RIA (EPA, 1999h). A copy
of the RIA and supporting documents is
available for public review in the Office
of Water docket at 401 M St. SW,
Washington, D.C.
  The risk of illness and death due to
cryptosporidiosis depends on several
factors, including the  age, nutrition,
exposure, and the immune status of the
individual. Information on mortality
from diarrhea shows the greatest risk of
mortality occurring among the  very
young and elderly (Gerba et al., 1996).
Specifically, young children are a
vulnerable population subject to
infectious diarrhea caused by
Cryptosporidium  (CDC 1994).
Cryptosporidiosis is prevalent
worldwide, and its occurrence  is higher
in children than in adults (Payer and
Ungar, 1986).
  Cryptosporidiosis appears to be more
prevalent in populations that may not
have established immunity against the
disease and may be in greater contact
with environmentally contaminated
surfaces, such as infants (DuPont, et al.,
1995). Once a child is infected  it may
spread the disease to other children or
family members. Evidence of such
secondary transmission of
cryptosporidiosis from children to
household and other close contacts has
been found in many outbreak
investigations (Casemore, 1990; Cordell
et al., 1997; Frost  et al., 1997). Chapell
et al., 1999, found that prior exposure to
Cryptosporidium through the ingestion
of a low oocyst dose provides protection
from infection and illness. However, it
is not known whether this immunity is
life-long or temporary. Data also
indicate that either mothers confer short
term immunity to their children or that
babies have reduced exposure to
Cryptosporidium, resulting in a
decreased incidence of infection during
the first year of life. For example, in a
survey of over 30,000  stool sample
analyses from different UK patients, the
1—5 year age group suffered a much
higher infection rate than individuals
less than one year of age. For children
under one year of age, those older than

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six months of age showed a higher rate
of infection than individuals aged fewer
than six months (Casemore, 1990).
  EPA has not been able to quantify the
differential health effects for children as
a result of Cryptosporidium-
contamSnated drinking water. However,
the result of the LTlFBR will be a
reduction in the risk of illness for the
entire population, including children.
Furthermore, the available anecdotal
evidence indicates that children may be
more vulnerable to cryptosporidiosis
than the rest of the population. The
LTlFBR would, therefore, result in
greater risk reduction for children than
for trie general population.
  The public is invited to submit or
identify peer-reviewed studies and data,
of which EPA may not be aware, that
assessed results of early life exposure to
Cryptosporidium.
H. Consultations ivith  the Science
Advisory Board, National Drinking
Water Advisory Council, and the
Secretary of Health and Human Services
  In accordance with section 1412 (d)
and (e) of the SDWA, the Agency will
consult with the National Drinking
Water Advisory Council (NDWAC) and
the Secretary of Health and Human
Services and request comment from the
Science Advisory Board on the
proposed LTlFBR.
/, Executive Order 13132: Executive
Orders on Federalism
  Executive Order 13132, entitled
"Federalism" (64 FR 43255, August 10,
1999), requires EPA to develop an
accountable process to ensure
"meaningful and timely input by State
and local officials in the development of
regulatory policies that have federalism
implications." "Policies that have
federalism  implications" is defined in
the Executive Order to include
regulations that have "substantial direct
effects on the States, on the relationship
between the national government and
the States, or on the distribution of
power and responsibilities among the
various levels of government."
   Under section 6 of Executive Order
13132, EPA may not issue a regulation
that has federalism implications, that
imposes substantial direct compliance
costs, and that is not required by statute,
unless the Federal government provides
the funds necessary to pay the direct
compliance costs incurred by State and
local governments, or  EPA consults with
State and local officials early in the
process of developing the proposed
regulation. EPA also may not issue a
regulation that has federalism
implications and that preempts State
law, unless the Agency consults with
State and local officials early in the
process of developing the proposed
regulation.
  If EPA complies by consulting,
Executive Order 13132 requires EPA to
provide to the Office of Management
and Budget (OMB),, in a separately
identified section of the preamble to the
final rule, a federalism summary impact
statement (FSIS). The FSIS must include
a description of the extent of EPA's
prior consultation with State and local
officials, a summary of the nature of
their concerns and the agency's position
supporting the need to issue the
regulation, and a statement of the extent
to which the concerns of State and local
officials have been met. Also, when EPA
transmits a draft final rule with
federalism implications to OMB for
review pursuant to Executive Order
12866, EPA must include a certification
from the agency's Federalism Official
stating that EPA has met the
requirements of Executive Order 13132
in a meaningful and timely manner.
  EPA has concluded that this proposed
rule may have federalism implications
since it may impose substantial direct
compliance costs on local governments,
and the Federal government will not
provide the funds necessary to pay
those cost. Accordingly, EPA provides
the following FSIS as required by
section 6(b) of Executive Order 13132.
  As discussed further in section
VT[.C.2.e, EPA met with a variety of
State and local representatives, who
provided meaningful and timely input
in the development of the proposed
rule. Summaries of the meetings have
been included in the public record for
this proposed rulemaking. EPA
consulted extensively with State, local,
and tribal governments. For example,
two public stakeholder meetings were
held on July 22-23, 1998, in Lakewood,
Colorado, and on March 3-4, 1999, in
Dallas, Texas. Several key issues were
raised by stakeholders regarding the LT1
provisions, many of which were related
to reducing burden and maintaining
flexibility. The Office of Water was able
to significantly reduce burden and
increase flexibility by tailoring
requirements to reduce monitoring,
reporting, and recordkeeping
requirements faced by small systems.
These modifications and others aided in
lowering the cost of the LTlFBR by $87
million (from $184.5 million to $97.5
million). It should be noted that this
rule is important because it will reduce
the level of Cryptosporidium in filtered
finished drinking water supplies
through improvements in filtration and
recycle practices resulting in a reduced
likelihood of outbreaks of
cryptosporidiosis. The rule is also
expected to increase the level of      :
protection from exposure to other
pathogens (i.e., Giardia and other
waterborne bacterial or viral pathogens).
Because consultation on this proposed
rule occurred before the November 2,
1999 effective date of Executive Order
13132, EPA will initiate discussions
with State and local elected officials
regarding the implications of this rule
during the public comment period.

/. Executive Order 13084: Consultation
and Coordination With Indian Tribal
Governments
  Under Executive Order 13084, EPA
may not issue a regulation that is not
required by statute, that significantly or
uniquely affects the communities of
Indian tribal governments, and that
imposes substantial direct compliance
costs on those communities, unless the
Federal government provides the funds
necessary to pay the direct compliance
costs incurred by the tribal governments
or EPA consults with those
governments. If EPA complies by
consulting, Executive Order 13084
requires EPA to provide to the Office of
Management and Budget,  in a separately
identified section of the preamble to the
rule, a description of the extent of EPA's
prior consultation with representatives
of affected tribal governments, a
summary of the nature of their concerns,
and a statement supporting the need to
issue the regulation. In addition,
Executive Order 13084 requires EPA to
develop an effective process permitting
elected officials and other
representatives of Indian tribal
governments "to provide meaningful
and timely input in the development of
regulatory policies on matters that
significantly or uniquely affect their
communities."
  EPA has concluded that this rule may
significantly or unique affect the
communities of Indian tribal
governments. It may also impose
substantial direct compliance costs on
such communities. The Federal
government will not provide the funds
necessary to pay all the direct costs
incurred by the Tribal governments in
complying with the rule. In developing
this rule, EPA consulted with
representatives of Tribal governments .
pursuant to UMRA and Executive Order
13084. EPA held extensive meetings
that provided Indian Tribal
governments the opportunity for
meaningful and timely input in the
development of the proposed rule.
Summaries of the meetings have been
included in the public docket for this
rulemaking. EPA's consultation, the
nature of the government's concerns,
and the position supporting the need for

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this rule are discussed in Section
VII.C.2.6, which addresses compliance
with UMRA.

K. Likely Effect of Compliance with the
LTlFBR on the Technical, Financial,
and Managerial Capacity of Public
Water Systems
  Section 1420(d)(3) of the SDWA as
amended requires that, in promulgating
a NPDWR, the Administrator shall
include an analysis of the likely effect
of compliance with the regulation on
the technical, financial, and managerial
capacity of public water systems. This
analysis can be found in the LTlFBR
RIA (EPA, 1999h).
  Overall water system capacity is
defined in EPA guidance (EPA, 1998J) as
the ability to plan for, achieve, and
maintain compliance with applicable
drinking water standards. Capacity has
three components: technical,
managerial, and financial.
  Technical capacity is the physical and
operational ability of a water system to
meet SDWA requirements. Technical
capacity refers to the physical
infrastructure of the water system,
including the adequacy of source water
and the adequacy of treatment, storage,
and distribution infrastructure. It also
refers to the ability of system personnel
to adequately operate and maintain the
system and to otherwise  implement
requisite technical knowledge. A water
system's technical capacity can be
determined by examining key issues
and questions, including:
  • Source water adequacy. Does the
system have a reliable source of
drinking water? Is the source of
generally good quality and adequately
protected?
  • Infrastructure adequacy. Can the
system provide water that meets SDWA
standards? What is the condition of its
infrastructure, including well(s) or
source water intakes, treatment, storage,
and distribution? What is the
infrastructure's life expectancy? Does
the system have a capital improvement
plan?
  • Technical knowledge and
implementation. Is the system's operator
certified? Does the operator have
sufficient technical knowledge of
applicable standards? Can the operator
effectively implement this technical
knowledge? Does the operator
understand the system's technical and
operational characteristics? Does the
system have an effective  operation and
maintenance program?
  Managerial capacity is the ability of a
water system to conduct its affairs to
achieve and maintain compliance with
SDWA requirements. Managerial
capacity refers to the system's;
                     institutional and administrative
                     capabilities. Managerial capacity can be
                     assessed through key issues and
                     questions, including:
                       •  Ownership accountability. Are the
                     system owner(s) clearly identified? Can
                     they be held accountable for the system?
                       •  Staffing and organization. Are the
                     system operator(s) and manager(s)
                     clearly identified? Is the system
                     properly organized and staffed? Do
                     personnel understand the management
                     aspects of regulatory requirements and
                     system operations? Do they have
                     adequate expertise to manage water
                     system operations? Do personnel have
                     the necessary licenses and
                     certifications?
                       •  Effective external linkages. Does the
                     system interact well with customers,
                     regulators, and other entities? Is the
                     system aware of available external
                     resources, such as  technical and
                     financial assistance?
                       Financial capacity is a water system's
                     ability to acquire and manage sufficient
                     financial resources to allow the system
                     to achieve and maintain compliance
                     with SDWA requirements. Financial
                     capacity can be assessed through key
                     issues and questions, including:
                       •  Revenue sufficiency. Do revenues
                     cover costs? Are water rates and charges
                     adequate to  cover the cost of water?
                       •  Credit worthiness. Is the system
                     financially healthy? Does it have access
                     to capital through public or private
                     sources?
                       •  Fiscal management and controls.
                     Are adequate books and records
                     maintained? Are appropriate budgeting,
                     accounting,  and financial planning
                     methods used? Does the system manage
                     its revenues effectively?
                       Systems not making significant
                     modifications to the treatment process
                     to meet LTlFBR requirements are not
                     expected to  require significantly
                     increased technical, financial, or
                     managerial capacity.

                     L. Plain Language
                       Executive Order 12866 and the
                     President's memorandum of June 1,
                     1998, require each agency to write its
                     rules in plain language. We invite your
                     comments on how to make this
                     proposed rule easier to understand. For
                     example: Have we  organized the
                     material to suit your needs? Are the
                     requirements in the rule clearly stated?
                     Does the rule contain technical language
                     or jargon that is not clear? Would a
                     different format (grouping and order of
                     sections, use of headings, paragraphing)
                     make the rule easier to understand?
                     Would shorter sections make the final
                     rule easier to understand? Could we
                     improve clarity by adding tables, lists,
or diagrams? What else could we do to
make the rule easier to understand?

VIII. Public Comment Procedures
  EPA invites you to provide your
views on this proposal, approaches we
have not considered, the potential
impacts of the various options
(including possible unintended
consequences), and any data or
information that you would like the
Agency to consider. Many of the
sections within today's proposed rule
contain "Request for Comment"
portions which the Agency is also
interested in receiving comment on.

A. Deadlines for Comment
  Send your comments on or before
June 9, 2000. Comments received after
this date may not be considered in
decision making on the proposed rule.
Again, comments must be received or
post-marked by midnight June 9, 2000.
B. Where To Send Comment
  Send an original and 3 copies of your
comments and enclosures (including
references) to W-99-10 Comment Clerk,
Water Docket (MC4101), USEPA, 401 M,
Washington, D.C. 20460. Comments
may also be submitted electronically to
ow-docket@epamail.epa.gov. Electronic
comments must be submitted as an
ASCII, WP5.1, WP6.1 or WPS file
avoiding the use of special characters
and form of encryption. Electronic
comments must be identified by the
docket number W-99-10. Comments
and data will also be accepted on disks
in WP 5.1, 6.1, 8 or ASCII file format.
Electronic comments on this notice may
be filed online at many Federal
Depository Libraries. Those who
comment and want EPA to acknowledge
receipt of their comments must enclose
a self-addressed stamped envelope. No
facsimiles (faxes) will be accepted.
Comments may also be submitted
electronically to ow-
docket@epamail.epa.gov.

C. Guidelines for Commenting
  To ensure that EPA can read,
understand and therefore  properly
respond to comments, the Agency
would prefer that commenters cite,
where possible, the paragraph(s) or
sections in the notice or supporting
documents to which each comment
refers. Commenters should use  a
separate paragraph for each issue
discussed. Note that the Agency is not
soliciting comment on, nor will it
respond to, comments on previously
published regulatory language that is
included in this notice to ease the
reader's understanding of proposed
language. You may find the following

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                                                                           19137
suggestions helpful for preparing your
comments:
  1. Explain your views as clearly as
possible.
  2. Describe any assumptions that you
used.
  3. Provide solid technical information
and/or data to support your views.
  4. If you estimate potential burden or
costs, explain how you arrived at the
estimate.
  5. Indicate what you support, as well
as what you disagree with.
  6. Provide specific examples to
illustrate your concerns.
  7. Make sure to submit your
comments by the deadline in this
proposed rule.
  8. At the beginning of your comments
(e.g., as part of the "Subject" heading),
be sure to properly identify the
document you are commenting on. You
can do this by providing the docket
control number assigned to the
proposed rule, along with the name,
date, and Federal Register citation.

IX. References
Adhara, S., Gagliado, P.,  Smith, D., Ross, D.,
    Gramith, K., and Trussell, R. 1998.
    Monitoring of Reverse Osmosis for Virus
    Rejection, Proceedings Water Quality
    and Technology Conference. 9pp.
Alvarez, M., Bellamy, B., Rose, J., Gibson, C.,
    and Mitskevich, G. 1999.
    Ciyptosporidium Removal Using a
    Pulsating Blanket Clariiier, Microsand
    Balloted Clarifier, and Dissolved Air
    Floatation in Treatment of a Highly
    Colored Florida Surface Water: A Pilot
    Study. Proceedings Water Quality and
    Technology Conference, 7pp.
American Society of Civil Engineers (ASCE)
    and American Water Works Association
     (AWWA). 1998. Chapter 8, High-Rate
    Granular Media Filtration Water
    Treatment Plant Design. McGraw Hill,
    New York, 23pp.
American Water Works Association
    Committee Report. 1983. Deterioration of
    water quality in large distribution
    reservoirs (open reservoirs). AWWA
     Committee on  Control of Water Quality
     in Transmission and Distribution
     Systems. J. AWWA. June 1983, 313-318.
American Water Works Association. 1991.
     Guidance Manual for Compliance With
     the Filtration and Disinfection
     Requirements for Public Water Systems
     Using Surface Water Sources. AWWA.
     Denver, 73pp.
American Water Works Association. 1998.
     Spent Filter Backwash Water Survey.
Amirtharajah, A. 1988. Some theoretical and
     conceptual views of filtration. J. AWWA.
     (80:12: 36-46)
APHA. 1995.19th Edition of Standard
     Methods for the Examination of Water
    and Wastewater, 1995. American Public
     Health Association.  1015 15th Street
     NW, Washington DC 20005. (Includes
     method 2130A, B).
Archer, J., Ball, J., Standridge, J., Greb, S.,
    Rasmussen, P., Masterson, J., and
    Boushon, L. 1995. Cryptosporidium spp.
    oocysts and Giardia spp. cyst
    occurrence, concentrations, and
    distribution in Wisconsin waters.
    Wisconsin Department of Natural
    Resources (PUBL-WR420-95:August),
    96pp.
Atherholt, T., LeChevallier, M., Norton, W.,
    and Rosen, J. 1998. Effect of rainfall on
    Giardia and crypto. J.AWWA (90:9:66-
    80).
Bailey, S., and Lippy, E. 1978. Should all
    finished water reservoirs be covered.
    Public Works. April 1978, 66-70.
Baudin, I., and Lame, J. 1998. Assessment
    and Optimization of Clarification Process
    for Cryptosporidium Removal.
    Proceedings of AWWA Water Quality
    and Technology Conference, Spp.
Bellamy, W., Cleasby, J., Logsdon, G., and
    Allen, M. 1993. Assessing Treatment
    Plant Performance. J. AWWA (85:12:34-
    38).
Bennett, J., Holmberg, S., Rogers, M., and
    Solomon, S. 1987. Infectious and
    parasitic diseases. Am. J. Prev. Med.
    3:102-114. In: R.W. Amler and H.B. Dull
    (Eds.), closing the gap: the burden  of
    unnecessary illness. Oxford University
    Press (112-114).
Bucklin, K., Amirtharajah, A., and Cranston,
    K. 1988. The characteristics of initial
    effluent quality and its implications for
    the filter-to-waste procedure. AWWARF.
    Denver, 158pp.
Campbell, S., Lykins, B., Goodrich,  J., Post,
    D., and Lay, T. 1995. "Package Plants for
    Small Systems: A Field Study," J.
    AWWA. (82:11:39-47).
Casemore, D. 1990. Epidemiological aspects
    of human cryptosporidiosis. Epidemiol.
    Infect. (104:1-28).
CDC 1998. CDC Morbidity and Mortality
    Weekly Report. Surveillance for
    Waterborne-Disease Outbreaks—United
    States, 1995-1996. December 11, 1998.
    Vol: 47. No. SS-5. US Department of
    Health and Human Services. CDC,
    Atlanta, GA.
CDC 1994. Addressing Emerging Infectious
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                       Pennsylvania Department of Environmental
                           Protection. 1999. Results of Filter Plant
                           Performance Evaluation Programs
                           conducted at Surface Water Systems
                           serving Fewer than 10,000 persons.
                       Patania, N., Jacangelo, J., Cummings, L.,
                           Wilczak, A., Riley, K., and Oppenheimer,
                           J. 1995. Optimization of Filtration for
                           Cyst Removal. AWWARF. Denver,
                           180pp.
                       Perz, J., Ennever, F., and Le  Blancq, S. 1998.
                           "Cryptosporidium in tap water;
                           Comparison of predicted risks with
                           observed levels  of disease." Amer. J.
                           Epidem. (147:289-301).
                       Petersen, C. 1992. Cryptosporidiosis in
                           patients infected with the human
                           immunodeficiency virus. Clin. Infect.
                           Dis. (15:903-909).
                       Pieniazek, N., Bornag-Uinaes, F., Slemenda,
                           S., daSilva, A., Moura, I., Arrowood, M.,
                           Ditrich, O. and Addiss,  D. New
                           Cryptosporidium Genotypes in HIV-
                           Infected Persons. 1999.  Emerging
                           Infectious Diseases. May—June 5:3: 444—
                           449.
                       Plummer, J., Edzwald, J., and Kelley, M.
                           1995. Removing Cryptosporidium by
                           dissolved-air floatation. J. AWWA
                           (87:9:85-95).
                       Pluntze, J. 1974. Health aspects of uncovered
                           reservoirs. Journal AWWA. August 1974,
                           pgs 432-437.
                       Randtke, S. 1999. Letter to Sarah Clark, City
                           of Austin Water and Wastewater Utility,
                           dated June 28,1999. Provided as
                           informal comment to EPA by AWWA.
                       Robeck, G., Dostal, K., and Woodward, R.
                           1964. Studies of Modification in Water
                           Filtration. J. AWWA (56:2:198-213).
                       Rose, J., Cifrino, A., Madore, M., Gerba, C.,
                           Sterling, C., and Arrowood, M. 1986.
                           Detection of Cryptosporidium from
                           Wastewater and Freshwater
                           Environments. Wat. Sci. Tec. (18:10:233-
                           239).
                       Rose, J. 1988. Occurrence and significance of
                           Cryptosporidium in water. J. AWWA
                           (80:2:53-58).
                       Rose, J., Darbin, H., and Gerba, C. 1988a.
                           Correlations of the protozoa
                           Cryptosporidium and Giardia with water
                           quality variables in a watershed. Proc.
                           Int. Conf. Water Wastewater Microbial.
                           Newport Beach, CA.
                       Rose, J., Kayed, D., Madore,  M., Gerba, C.,
                           Arrowood, M., and Sterling, C. 1988b.
                           Methods for the recovery of Giardia and
                           Cryptosporidium from environmental
                           waters and their comparative occurrence.
                           In: P.Wallis and B. Hammond, eds.
                           Advances in Giardia Research. Calgary,
                           Canada: University of Calgary Press.
                       Rose, J., Gerba, C., and Jakubowski, W. 1991.
                           Survey of potable water supplies for
                           Cryptosporidium and Giardia. Environ.
                           Sci. and Technol. (25:8:1393-1400).
                       Rose, J. 1997. Environmental ecology of
                           Cryptosporidium and public health
                           implications. Annual Rev. Public Health
                           (18:135-161).
                       Rosen, J., LeChevallier, M., and Roberson, A.
                           1996. Development and Analysis of a
                           National Protozoa Database, 15pp.
                       SAIC. 1997a. Microscopic Particulate
                           Analysis (MPA)  Correlations with
    Giardia and Cryptosporidium
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    SAIC, McLean, VA (September 4, 1997).
Schuler, P., and Gosh, M. 1991. Slow Sand
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                                                                      19141
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List of Subjects

40 CFR Part 141

   Environmental protection, Chemicals,
Indians-lands, Intergovernmental
relations, Radiation protection,
Reporting and recordkeeping
requirements, Water supply.

40 CFR Part 142

   Environmental protection,
Administrative practice and procedure,
Chemicals, Indians-lands, Radiation
protection, Reporting and recordkeeping
requirements, Water supply.
  Dated: March 27, 2000.
Carol M. Browner,
Administrator.
   For the reasons set forth in the
preamble, title 40 chapter I of the Code
of Federal Regulations is proposed to be
amended as follows:
PART 141—NATIONAL PRIMARY
DRINKING WATER REGULATIONS

  3. The authority citation for part 141
continues to read as follows:
  Authority: 42 U.S.C. 300f, 300g-l, 300g-2,
300g-3, 300g-4, 300g-5, 300g-6, 300J-4,
300J-9, and 300J-11.

  4. Section 141.2 is amended by
revising the definition of "Ground water
under the direct influence of surface
water" and "Disinfection profile" and
adding the following definitions in
alphabetical order to read as follows:

§141.2  Definitions.
*****
  Direct recycle is the return of recycle
flow within the treatment process of a
public water system without first
passing the recycle flow through a
treatment process designed to remove
solids, a raw water storage reservoir, or
some other structure with a volume
equal to or greater than the volume of
spent filter backwash water produced by
one filter backwash event.
*****
  Disinfection profile is a summary of
Giardia lamblia inactivation through the
treatment plant, from the point of
disinfectant application to the first
customer. The procedure for developing
a disinfection profile is contained in
§ 141.172 (Disinfection profiling and
benchmarking) in subpart P and
§§ 141.530-141.536 (Disinfection  ,
profile) in subpart T of this part.
*****
  Equalization is the detention of
recycle flow in a structure with a
volume equal to or greater than the
volume of spent filter backwash
produced by one filter backwash event.
*****
  Ground water under the direct
influence of surface water (GWUDI)
means any water beneath the surface of
the ground with significant occurrence
of insects or other macroorganisms,
algae, or large-diameter pathogens such
as Giardia lamblia or Cryptosporidium,
or significant and relatively rapid shifts
in water characteristics such as
turbidity, temperature, conductivity, or
pH which closely correlate to
climatological or surface water
conditions. Direct influence must be
determined for individual sources in
accordance with criteria established by
the State. The State determination of
direct influence may be based on site-
specific measurements of water quality
and/or documentation of well
construction characteristics and geology
with field evaluation.
  Membrane Filtration means any
filtration process using tubular or spiral
wound elements that exhibits the ability
to mechanically separate water from
other ions and solids by creating a
pressure differential and flow across a
membrane with an absolute pore size <1
  Operating capacity is the maximum
finished water production rate approved
by the State drinking water program.
*****
  Recycle is the return of any water,
solid, or semisolid generated by plant
treatment processes, operational
processes, maintenance processes, and
residuals treatment processes into a
PWS's primary treatment processes.
*****
  5. Section 141.32 is amended by
revising paragraph (e)(10) to read as
follows:

§ 141.32  Public notification.
*****
  (e)* *  *
  (10) Microbiological contaminants (for
use when there is a violation of the
treatment technique requirements for
filtration and disinfection in subpart H,
subpart P, or subpart T of this part). The
United States Environmental Protection
Agency (EPA) sets drinking water
standards and has determined that the
presence of microbiological
contaminants are a health concern at  '
certain levels of exposure. If water is
inadequately treated, microbiological
contaminants in that water may cause
disease. Disease symptoms may include
diarrhea, cramps, nausea, and possibly
jaundice,  and any associated headaches
and fatigue. These symptoms, however,
are not just associated with disease-
causing organisms in drinking water,
but also may be caused by a number of
factors other than your drinking water.
EPA has set enforceable requirements
for treating drinking water to reduce the
risk of these adverse health effects.
Treatment such as filtering and
disinfecting the water removes or     ;
destroys microbiological contaminants.
Drinking water which is treated to meet
EPA requirements is associated with
little to none of this risk and should be
considered safe.
*****
  6. Section 141.70 is amended by
revising paragraph (b)(2) and adding
paragraph (e) to read as follows:

§141.70  General requirements.
*****
  (b)* *  *
  (2) It meets the filtration requirements
in § 141.73, the disinfection

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19142
Federal Register/Vol. 65, No,  69/Monday, April  10,  2000/Proposed Rules
requirements in § 141.72(b) and the
recycle requirements in § 141.76.
*****
  (e) Additional requirements for
systems serving fewer than 10,000
people. In addition to complying with
requirements in this subpart, systems
serving fewer than 10,000 people must
also comply with the requirements in
subpart T of this part.
  7. Section 141.73 is amended by
adding paragraph (a)(4) and revising
paragraph (d) to read as follows:

§141.73   Filtration.
*****
  (a)* * *
  (4) Beginning [DATE 36 MONTHS
AFTER DATE OF PUBLICATION OF
FINAL RULE IN THE FEDERAL
REGISTER], systems serving fewer than
10,000 people must meet the turbidity
                    requirements in §§ 141.550 through
                    141.553.
                    *****
                      (d) Other filtration technologies. A
                    public water system may use a filtration
                    technology not listed in paragraphs (a)
                    through (c) of this section if it
                    demonstrates to the State, using pilot
                    plant studies or other means, that the
                    alternative filtration technology, in
                    combination with disinfection treatment
                    that meets the requirements of
                    § 141.72(b), consistently achieves 99.9
                    percent removal and/or inactivation of
                    Giardia lamblia cysts and 99.99 percent
                    removal and/or inactivation of viruses.
                    For a system that makes this
                    demonstration, the requirements of
                    paragraph (b) of this section apply.
                    Beginning December 17, 2001, systems
                    serving at least 10,000 people must meet
                    the requirements for other filtration
technologies in paragraph (b) of this
section. Beginning [DATE 36 MONTHS
AFTER DATE OF PUBLICATION OF
FINAL RULE IN THE FEDERAL
REGISTER], systems serving fewer than
10,000 people must meet the
requirements for treatment technologies
in §§ 141.550 throughl41.553.
  8. Subpart H is amended by adding a
new § 141.76 to subpart H to read as
follows:

§ 141.76  Recycle Provisions.
  (a) Public water systems employing
conventional filtration or direct
filtration that use surface water or
ground water under the direct influence
of surface water and recycle within the
treatment process must meet all
applicable requirements  of this section.
Requirements are  summarized in the
following table.
                                  RECYCLE PROVISIONS FOR SUBPART H SYSTEMS
If you are a ...
(1) subpart H public water system employing conventional or direct filtration re-
turning spent filter backwash, thickener supernatant, or liquids from dewatering
processes concurrent with or downstream of the point of primary coagulant ad-
dition.
(2) Plant that is part of a subpart H public water system, employ conventional fil-
tration treatment, practice direct recycle, employ 20 or fewer filters to meet pro-
duction requirements during the highest production month in the 12 month pe-
riod [date 60 months after publication of final rule], and recycle spent filter
backwash or thickener supernatant to the treatment process.
(3) subpart H public water system practicing direct filtration and recycling to the
treatment process.
You are
required to meet the requirements in ...
§141.76(b).
§141.76(c).
§141.76(d).
  (b) Recycle return location. All
subpart H systems employing
conventional filtration or direct
filtration and returning spent filter
backwash, thickener supernatant, or
liquids from dewatering processes at or
after the point of primary coagulant
addition must return these recycle flows
prior to the point of primary coagulant
addition by [DATE 60 MONTHS AFTER
DATE OF PUBLICATION OF FINAL
RULE IN THE FEDERAL REGISTER].
The system must apply to the State for
approval of the change in recycle
location before the system implements
it.
  (1) All subpart H systems employing
conventional filtration or direct
filtration, returning spent filter
backwash, thickener supernatant, or
liquids from dewatering processes at or
after the point of primary coagulant
addition must submit a plant schematic
to the State by [DATE 42 MONTHS
AFTER DATE OF PUBLICATION OF
FINAL RULE IN THE FEDERAL
REGISTER] showing the current recycle
return location(s) for the recycle
stream(s) and the new return location
                    that will be used to establish
                    compliance. The system must keep the
                    plant schematic on file for review
                    during sanitary surveys.
                      (2)  Softening systems may recycle
                    process solids at the point of lime
                    addition preceding the softening process
                    to improve treatment efficiency. Process
                    solids may not be returned prior to the
                    point of lime addition. Softening
                    systems shall not return spent filter
                    backwash, thickener supernatant, or
                    liquids  from dewatering processes to a
                    location other than prior to the point of
                    primary coagulant addition unless an
                    alternate location is granted by the
                    State.
                      (3)  Contact clarification systems may
                    recycle  process solids directly into the
                    contactor. Contact clarification systems
                    shall not return spent filter backwash,
                    thickener  supernatant, or liquids from
                    dewatering processes to  a location other
                    than prior to the point of primary
                    coagulant addition unless an alternate
                    location is granted by the State.
                      (4)  Systems may apply to the State to
                    return spent filter backwash, thickener
                    supernatant, or liquids from dewatering
processes to an alternate location other
than prior to the point of primary
coagulant addition.
  (c) Plants that are part of subpart H
public water systems that employ
conventional rapid granular filtration,
practice direct recycle, employ 20 or
fewer filters to meet production
requirements during the highest
production month in the 12  month
period prior to [DATE 60 MONTHS
AFTER PUBLICATION OF FINAL RULE
IN THE Federal Register], and recycle
spent filter backwash or thickener
supernatant to the primary treatment
process shall complete a recycle self
assessment, as stipulated in
paragraphs(c)(l) and (c)(2) by [Date 51
Months After Date of Publication of  '
Final Rule in the Federal Register].
Systems required to perform the self
assessment shall:
  (1) Submit a recycle self assessment
monitoring plan to the State no later
than [Date 39 Months After Date of
Publication of Final Rule in  the Federal
Register]. At a  minimum, the
monitoring plan must identify the
highest water production month during

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                  Federal Register/Vol.  65,  No. 69/Monday,  April 10,  2000/Proposed Rules
                                                                   19143
which monitoring will be conducted,
contain a schematic identifying the
location of raw and recycle flow
monitoring devices, describe the type of
flow monitoring devices to be used,
identify the system's State approved
operating capacity, and describe how
data from the raw and recycle flow
monitoring devices will be
simultaneously retrieved and recorded.
  (2) Implement the following recycle
self assessment monitoring and analysis
steps:
  p) Steps for Implementation of
Recycle Self Assessment:
  (A)  Identify the highest water
production month during the 12 month
period preceding [Date 36 Months After
Date of Publication of Final Rule in the
Federal Register].
  (B) Perform the monitoring described
in paragraph (c)(2)(i)(C) of this section
during the 12 month period after
submission of the monitoring plan to
the State. The twelve month period
must begin no later than [Date 39
Months After Date of Publication of
Final  Rule in the Federal Register].
  (C) For each day of the month
identified in paragraph (c)(2)(i)(A) of
this section, separately monitor source
water influent flow and recycle flow
before their confluence during one filter
backwash recycle event per day, at three
minute intervals during the duration of
the event. Monitoring must be
performed between 7:00 a.m. and 8:00
p.m. Systems that do not have a filter
backwash recycle event every day
between 7:00 am and 8:00 p.m. must
monitor one filter backwash recycle
event per day, any three days of the
week, for each week during the month
of monitoring, between 7:00 a.m. and
8:00 p.m. Record the time filter
backwash was initiated, the influent and
recycle flow at three minute intervals
during the duration of the event, and the
time the filter backwash recycle event
ended. Record the number of filters in
use when the filter backwash recycle
event is monitored.
  (D)  Calculate the arithmetic average of
all influent and recycle flow values
taken at three minute intervals in
paragraph (c)(2)(i)(c) of this section.
Sum the arithmetic average calculated
for raw water influent and recycle flows.
Record this value and the date the
monitoring was performed. This value is
referred to as event flow.
  (E) After the month of monitoring is
complete, order the event flows in a list
of increasing order, from lowest to
highest. Highlight the event flows that
exceed State approved operating
capacity and then sum the number of
event flows highlighted.
  (ii)  [Reserved]
  (3) Subpart H systems performing
recycle self assessments are required to
report the results of the self assessment
and supporting documentation to the
State within one month of completing
raw water influent and recycle flow
monitoring. The report must be
submitted no later than [DATE 52
MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER]. If the State
determines the self assessment is
incomplete or inaccurate, it may require
the system to correct deficiencies or
perform an additional self assessment.
At a minimum, the report must contain
the following information:
  (i) Minimum Information Included in
Recycle Assessment Report to State:
  (A) All source and recycle flow
measurements taken and the dates they
were taken. For all events monitored,
report the times the filter backwash
recycle event was initiated, the flow
measurements taken at three minute
intervals, and the time the filter
backwash recycle event ended. Report
the number of filters in use when the
backwash recycle event is monitored,
  (B) All data used and calculations
performed to determine whether the
system exceeded operating capacity
during monitored recycle events and the
number of event flow values that
exceeded State approved operating
capacity.
  (C) A plant schematic showing the
origin of all recycle flows, the hydraulic
conveyance used to transport them, and
their final destination in the plant.
  (D) A list of all the recycle tlows and
the frequency at which they are
returned to the plant's primary
treatment process.
  (E) Average and maximum backwash
flow rate through the filters and the
average and maximum duration of the
filter backwash process, in minutes.
  (F) Typical filter run length and a
written summary of how filter run
length is determined (preset run time,
headloss, turbidity breakthrough, etc.).
  (ii) [Reserved]
  (4) All subpart H systems performing
self assessments are required to modify
their recycle practice in accordance
with the State determination by [DATE
60 MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER] and keep a
copy of the self assessment report
submitted to die State on file for review
during sanitary surveys.
  (d) Subpart H public water systems
practicing direct filtration and recycling
to the primary treatment process are
required to submit data to the State on
their current recycle treatment no later
than [DATE 42 MONTHS AFTER DATE
OF PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER.]
  (l) Direct filtration systems
submitting data to the State shall report
the following information, at a
minimum:
  (i) Data Submitted to States by Direct
Filtration Systems:
  (A) A plant schematic showing the
origin of all recycle flows, the hydraulic
conveyance used to transport them, and
their final destination in the plant.
  (B) The number of filters used at the
plant to meet average daily production
requirements and average and
maximum backwash flow rate through
the filter and the average and maximum
duration of the filter backwash process,
in minutes.
  (C) Whether recycle flow treatment or
equalization is in place.
  (D) The type of treatment provided for
the recycle flow.
  (E) For recycle equalization and
treatment units: data on the physical
dimensions of the unit (length, width
(or circumference), depth,) sufficient to
allow calculation of volume; typical and
maximum hydraulic loading rate; type
of treatment chemicals used and average
dose and frequency of use, and
frequency at which solids are removed
from the unit, if applicable.
  (ii) [Reserved]
  (2) All direct filtration systems
submitting data to the State are required
to modify their recycle practice in
accordance with the State determination
no later than [DATE 60 MONTHS
AFTER DATE OF PUBLICATION OF
FINAL RULE IN THE FEDERAL
REGISTER] and keep a copy of the
report submitted to the State on file for
review during sanitary surveys.
  9. Section 141.153 is amended by
revising the first sentence of paragraph
(d)(4)(v)(C) to read as follows:

§141.153  Content of the reports.
*****
  (d)* * *
  (4) * * *
  (V)* * *
  (C) When it is reported pursuant to
§ 141.73 or § 141.173 or § 141.551: the
highest single measurement and the
lowest monthly percentage of samples
meeting the turbidity limits specified in
§ 141.73 or § 141.173, or § 141.551 for
the filtration technology being used.
  10. The heading to Subpart P is
revised as follows:

Subpart P—Enhanced Filtration and
Disinfection-Systems Serving 10,000
or More People

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Federal Register/Vol. 65,  No. 69/Monday, April 10, 2000/Proposed Rules
  11. Section 141.170 is amended by
adding paragraph (d) to read as follows:

§141.170  General requirements.
*****

  (d) Subpart H systems that did not
conduct applicability monitoring under
§ 141.172 because they served fewer
than 10,000 persons when such
monitoring was required but serve more
than 10,000 persons prior to [DATE 36
MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER] must
comply with §§ 141.170, 141.171,
141.173, 141.174, and 141.175. TJiese
systems must also consult with the State
to establish a disinfection benchmark. A
system that decides to make a
significant change to its disinfection
practice, as described in
§ 141.172(c)(lHi) through (iv) must
consult with, the State prior to making
such change.
*****

  12. Part 141 is amended by adding a
new subpart T  to read as follows:

Subpart T—Enhanced Filtration and
Disinfection—Systems Serving Fewer
than 10,000 People

Sec.
General Requirements
141.500 General requirements.
141.501 Who is subject to the requirements
    of subpart T?
141.502 When must my system comply
    with these requirements?
141.503 What does subpart T require?,
Finished Water Reservoirs
141.510 Is my system subject to the new
    finished water reservoir requirements?
141.511 What is required of new finished
    water reservoirs?
Additional Watershed Control Requirements
141.520 Is my system subject to the updated
    watershed control requirements?
141.521 What updated watershed control'
    requirements must my system comply
    with?
141.522 How does the State determine
    whether my  system's watershed control
    requirements are adequate?
Disinfection Profile
141.530 Who must develop a Disinfection
    Profile and what is a Disinfection
    Profile?
141.531 How does my system demonstrate
    TTHM and HAAS levels below 0.064
   mg/1 and 0.048 mg/1 respectively?
141.532 How does my system develop a
    Disinfection Profile and when must it
   begin?
141.533 What measurements must my
    system collect to calculate a Disinfection
   Profile?
141.534 How does my system use these
   measurements to calculate an
   inactivation ratio?
                      141.535  How does my system develop a
                         Disinfection Profile if we use
                         chloramines, ozone, or chlorine dioxide
                         for primary disinfection?
                      141.536  If my system has developed an
                         inactivation ratio; what must we do
                         now?
                      Disinfection Benchmark
                      141.540  Who has to develop a Disinfection
                         Benchmark?
                      141.541  What are significant changes to
                         disinfection practice?
                      141.542  How is the Disinfection Benchmark
                         calculated?
                      141.543  What if my system uses
                         chloramines or ozone for primary
                         disinfection?
                      141.544 ' What must my system do if
                         considering a significant change to
                         disinfection practices?
                      Combined Filter Effluent Requirements
                      141.550  Is my system required to meet
                         subpart T combined filter effluent
                         turbidity limits?
                      141.551  What strengthened combined filter
                         effluent turbidity limits must my system
                         meet?
                      141.552  If my system consists of
                         "alternative filtration" and is required to
                         conduct a demonstration, what is
                         required of my system and how does the
                         State establish my turbidity limits?
                      141.553  If my system practices lime
                         softening, is there any special provision
                         regarding my combined filter effluent?
                      Individual Filter Turbidity Requirements
                      141.560  Is my system subject to individual
                         filter turbidity requirements?
                      141.561  What happens if my turbidity
                         monitoring equipment fails?
                      141.562  What follow-up action is my
                         system required to take based on
                         turbidity monitoring of individual
                         filters?
                      141.563 My system practices lime
                         softening. Is  there any special provision
                         regarding my individual filter turbidity
                         monitoring?
                      Reporting and Recordkeeping Requirements
                      142.570 What does subpart T require that
                         my system report to the State?
                      142.571 What records does subpart T
                         require my system to keep?

                      Subpart T—Enhanced Filtration and
                      Disinfection—Systems Serving Fewer Than
                      10,000 People

                      General Requirements

                      § 141.500  General requirements.
                       The requirements of subpart T
                      constitute national primary drinking
                     water regulations. These  regulations
                      establish requirements for filtration and
                      disinfection that are in addition to
                      criteria under which filtration and
                      disinfection are required under subpart
                     H of this part. The regulations in this
                      subpart establish or extend treatment
                     technique requirements in lieu of
                     maximum contaminant levels fpr the
                     following contaminants:  Giardia
 lamblia, viruses, heterotrophic plate
 count bacteria, Legionella,
 Cryptosporidium and turbidity. The
 treatment technique requirements
 consist of installing and properly
 operating water treatment processes
 which reliably achieve:
   (a) At least 99 percent (2 log) removal
 of Cryptosporidium between a point
 where the raw water is not subject to
 recontamination by surface water runoff
 and a point downstream before or at the
 first customer for filtered  systems, or
 Cryptosporidium control under the
 watershed control plan for unfiltered
 systems.
   (b) Compliance with the profiling and
 benchmark requirements  in §§ 141.530
 through 141.544.

 §141.501  Who is subject to the
 requirements of subpart T?
   You are subject to these requirements
 if your system:
   (a) Is a public water system;
   (b) Uses surface water or GWUDI as a
 source; and
   (c) Serves fewer than 10,000 persons
 annually.

 §141.502  When must my system comply
 with these requirements?
   You must comply with  these
 requirements beginning [DATE 36
 MONTHS AFTER DATE OF
 PUBLICATION OF FINAL RULE IN
 THE FEDERAL REGISTER] except
 where otherwise noted.

 § 141.503  What does subpart T require?
   There are six requirements of this
 subpart which your system may need to
 comply with. These requirements are
 discussed in detail later in this subpart.
 They are:
   (a) Any finished water reservoir for
 which construction begins on or after
 [DATE 60 DAYS AFTER DATE OF
 PUBLICATION OF FINAL RULE IN
 THE FEDERAL REGISTER] must be
 covered;
   (b) Unfiltered systems must comply
 with updated watershed control
 requirements;
   (c) All systems subject to the
 requirements of this subpart must
 develop a disinfection profile;
   (d) All systems subject to the
 requirements of this subpart that are
 considering a significant change to their
 disinfection practice must develop a
 disinfection benchmark and receive
 State approval before changing their
 disinfection practice;
   (e) Filtered systems must comply with
 specific combined filter effluent
turbidity limits and monitoring and
reporting requirements; and
   (f) Filtered systems using
conventional or direct filtration must

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                  Federal Register/Vol.  65,  No. 69/Monday, April 10, 2000/Proposed  Rules
                                                                     19145
comply with individual filter turbidity
limits and monitoring and reporting
requirements.
Finished Water Reservoirs

§ 141.510  Is my system subject to the new
finished water reservoir requirements?
  All subpart H systems which serve
populations fewer than 10,000 are
subject to this requirement.
§141.511  What is required for new
finished water reservoirs?
  If your system initiates construction
of a finished water reservoir after [DATE
60 DAYS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER the reservoir
must be covered. Finished water
reservoirs constructed prior to [DATE 60
DAYS AFTER DATE OF PUBLICATION
OF FINAL RULE IN THE FEDERAL
REGISTER are not subject to this
requirement,
Additional Watershed Control
Requirements
§ 141.520  Is my system subject to the
updated watershed control requirements?
  If you are a subpart H system serving
fewer than 10,000 persons which does
not provide filtration, you must
continue to comply with all of the
watershed control requirements in
§ 141.71, as well as the additional
watershed control requirements in
§141.521.
§ 141.521  What additional watershed
control requirements must my system
comply with?
  Your system must also maintain the
existing watershed control program to
minimize the potential for
contamination by Cryptosporidium
oocysts in the source water. Your
system's watershed control program
must, for Cryptosporidium:
  (a) Identify watershed characteristics
and activities which may have an
adverse effect on source water quality;
and
  (b) Monitor the occurrence of
activities which may have an adverse
effect on source water quality.
§ 141.522  How does the State determine
whether my system's watershed control
requirements are adequate?
  During an onsite inspection
conducted under the provisions of
§ 141.71 [b)(3), the State must determine
whether your watershed control
program is adequate to limit potential
contamination by Cryptosporidium
oocysts. The adequacy of the program
must be based on the
comprehensiveness of the watershed
review; the effectiveness of your
program to monitor and control
detrimental activities occurring in the
watershed; and the extent to which your
system has maximized land ownership
and/or controlled land use within the
watershed.
Disinfection Profile

§ 141.530   Who must develop a
Disinfection Profile and what is a
Disinfection Profile?
  All subpart H community and non-
transient non-community water systems
which serve fewer than 10,000 persons
must develop a disinfection profile. A
disinfection profile is a graphical
representation of your system's level of
Giardia lamblia or virus inactivation
measured during the course of a year.
Your system must develop a
disinfection profile unless you can
demonstrate to the State that your
TTHM and HAAS levels are less than
0.064 mg/1 and 0.048 mg/1 respectively,
prior to January 7, 2003.

§ 141.531   How does my system
demonstrate TTHM and HAAS levels below
0.064 mg/l and 0.048 mg/l respectively?
  In order to demonstrate that your
TTHM and HAAS levels are below 0.064
mg/L and  0.048 mg/L, respectively your
system must have collected one TTHM
and one HAAS sample taken between
1998-2002. Samples must have been
collected during the month with the
warmest water temperature, at the point
of maximum residence time in your
distribution system which indicate
TTHM levels below 0.064 mg/l and
HAAS levels below 0.048 mg/L. By
January 7, 2003, you must submit a copy
of the results to the State along with a
letter indicating your intention to forgo
development of a disinfection profile
because of the results of the sampling.
This letter, along with a copy of your
TTHM and HAAS sample lab results
must be kept on file for review by the
State during a sanitary survey. If the
data you have collected is either equal
to or exceeds either 0.064 mg/l for
TTHM and/or 0.048 mg/l for HAASs,
you must develop a disinfection profile.

§ 141.532 How does my system develop a
Disinfection Profile and when must it
begin?
  A disinfection profile consists of three
steps:
  (a) First, your system must collect
measurements for several treatment
parameters from the plant as discussed
in § 141.533. Your system must begin
this monitoring no later than January 7,
2003.
  (b) Second, your system must use
these measurements to calculate
inactivation ratios as discussed in
§§ 141.534 and 141.535; and
  (c) Third, your system must use these
inactivation ratios to develop a
disinfection profile as discussed in
§141.536.

§ 141.533 What measurements must my
system collect to calculate a Disinfection
Profile?
  Your system must monitor the
parameters necessary to determine the
total inactivation ratio using analytical
methods in § 141.74 (a), once per  week
on the same calendar day each week as
follows:
  (a) The temperature of the disinfected
water must be measured at each residual
disinfectant concentration sampling
point during peak hourly flow;
  (b) If the system uses chlorine, the pH
of the disinfected water must be
measured at each chlorine residual
disinfectant concentration sampling
point during peak hourly flow;
  (c) The disinfectant contact time(s)
("T") must be determined during  peak
hourly flow; and
  (d) The residual disinfectant
concentration(s) ("C") of the water
before or at the first customer and prior
to each additional point of disinfection
must be measured during peak hourly
flow.

§ 141.534 How does my system use these
measurements to calculate an inactivation
ratio?
  Calculate the total inactivation ratio
as follows, and multiply the value by
3.0 to determine log inactivation of
Giardia lamblia:
                       If a system...
                                    The system must determine...
(a) Uses only one point of disinfectant application
                   (1) One inactivation ratio (CTcalc/CT99.9) before or at the first customer
                     during peak hourly flow, or

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Federal Register/Vol. 65,  No. 69/Monday, April 10, 2000/Proposed Rules
                         If a system...
                                                                              The system must determine...
 (b) Uses more than one point of disinfectant application before the first
   customer.
                                          (2) Successive CTcalc/CT99.9 values, representing sequential inactiva-
                                           tion ratios, between the point of disinfectant application and a point
                                           before or at the first customer during peak hourly flow. Under this al-
                                           ternative, the system must calculate the total inactivation ratio by de-
                                           termining (CTcaIc/CT99.9) for each sequence and then  adding the
                                           (CTcalc/CT99.9) values together to determine (Z (CTcalc/CT99.9)). You
                                           may use a spreadsheet that calculates CT and/or contains the nec-
                                           essary inactivation tables.
                                          (1) The CTcalc/CT99.9 value  of each disinfection segment immediately
                                           prior to the next point of disinfectant application, or for the final seg-
                                           ment, before or at  the first customer, during peak hourly flow using
                                           the procedure described in the above paragraph.
 § 141.535  How does my system develop a
 Disinfection Profile if we use chloramines,
 ozone, or chlorine dioxide for primary
 disinfection?
   If your system uses either
 chloramines, ozone or chlorine dioxide
 for primary disinfection, you must also
 calculate the logs of inactivation for
 viruses. You must develop an additional
 disinfection profile for viruses using a
 method approved by the State.

 § 141.536  If my system has developed an
 inactivation ratio, what must we do now?
   Each inactivation ratio serves as a
 data point in your disinfection profile.
 Your system will have obtained 52
 measurements (one for every week of
 the year). This will allow your system
 and the State the opportunity to
 evaluate how microbial inactivation
 varied over the course of the year by
 looking at all 52 measurements (your
 Disinfection Profile). Your system must
 retain the Disinfection Profile data in
 graphic form, as a spreadsheet, or in
 some other format acceptable to the
 State for review as part of sanitary
 surveys conducted by the State. Your
 system will need to use this data to
 calculate a benchmark if considering
 changes to disinfection practices.

 Disinfection Benchmark

 § 141.540  Who has to develop a
 Disinfection Benchmark?
  If you are a subpart H system required
 to develop a disinfection profile under
 §§ 141.530 through 141.536, your
 system must develop a Disinfection
 Benchmark if you decide to make a
 significant change to disinfection
practice. State approval must be
 obtained before you can implement a
significant disinfection practice change.

§ 141.541 What are significant changes to
disinfection practice?
  Significant changes to disinfection
practice are:
  (a) Changes to the point of
disinfection;
                       (b) Changes to the disinfectant(s) used
                     in the treatment plant;
                       (c) Changes to the disinfection
                     process; or
                       (d) Any other modification identified
                     by the State.

                     § 141.542  How is the Disinfection
                     Benchmark Calculated?
                       If your system is making a significant
                     change to its disinfection practice, it
                     must calculate a disinfection benchmark
                     using the following procedure:
                       (a) To calculate a disinfection
                     benchmark a system must perform the
                     following steps:
                       Step 1: Using the data your system
                     collected to develop the Disinfection
                     Profile,  determine the average Giardia
                     lamblia inactivation for each calender
                     month by dividing the sum of all
                     Giardia lamblia inactivations for that
                     month by the number of values
                     calculated for that month.
                       Step 2: Determine the lowest monthly
                     average  value out of the twelve values.
                     This value becomes the disinfection
                     benchmark.
                       (b) [Reserved]

                     § 141.543 What if my system uses
                     chloramines or ozone for primary
                     disinfection?
                       If your system uses chloramines,
                     ozone or chlorinated dioxide for
                     primary disinfection your system must
                     calculate the disinfection benchmark
                     from the data your system collected for
                     viruses to develop the disinfection
                     profile in addition to the Giardia
                     lamblia  disinfection benchmark
                     calculated under § 141.542. The
                     disinfection benchmark must be
                     calculated as described in §141.542.

                     § 141.544 What must my system do if
                     considering a significant change  to
                     disinfection practices?
                       If your system is considering a
                     significant change to the disinfection
                     practice, it must complete a disinfection
                     benchmark(s) as described in §§ 141.542
                     and 141.543 and provide the
 benchmark(s) to your State. Your system
 may only make a significant disinfection
 practice change after receiving State
 approval. The following information
 must be submitted to the State as part
 of their review and approval process:
   (a) A description of the proposed
 change;
   (b) The disinfection profile for Giardia
 lamblia (and, if necessary, viruses) and
 disinfection benchmark;
   (c) An analysis of how the proposed
 change will affect the current levels of
 disinfection; and
   (d) Additional information requested
 by the State.

 Combined Filter Effluent Requirements

 § 141.550  Is my system required to meet
 subpart T combined filter effluent turbidity
 limits?
   All subpart H systems •which serve
 populations fewer than 10,000, and are
 required to filter, must meet combined
 filter effluent requirements. Unless your
 system consists of slow sand or
 diatomaceous earth filtration, you are
 required to meet the combined filter
 effluent turbidity limits in § 141.551. If
 your system uses slow sand or
 diatomaceous earth filtration you must
 continue to meet the combined filter
 effluent turbidity limits in § 141.73.

 § 141.551  What strengthened combined
 filter effluent turbidity limits must my
 system meet?
  Your system must meet two
 strengthened combined filter effluent
 turbidity limits.
  (a) The first combined filter effluent
 turbidity limit is a "95th percentile"
 turbidity limit which your system must
 meet in at least 95 percent of the
 turbidity measurements taken each
 month.  Measurements must continue to
be taken as described in § 141.74(a) and
 (c). The following table describes the
required limits for specific filtration
technologies.

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                                                                       19147
                 If your system consists of ...
                                                                        Your 95th percentile turbidity value is ...
(1) Conventional filtration or direct filtration
(2) Membrane filtration  	
(3) All other "alternative" filtration
                    0.3 NTU.
                    0.3 NTU or a value determined by the State (not to exceed  1 NTU)
                      based on a demonstration conducted by the system as described in
                      §141.552.
                    A value determined by the State (not to exceed 1 NTU) based on the
                      demonstration described in § 141.552.
  (b) The second combined filter
effluent turbidity limit is a "maximum"
turbidity limit which your system may
at no time exceed during the month.
Measurements must continue to be
taken as described in § 141.74(a) and (c).
                                        The following table describes the
                                        required limits for specific filtration
                                        technologies.
If your system consists of ...


(3) AH other "alternative" filtration 	

Your maximum turbidity value is ...
1 NTU.
1 NTU or a value determined by the State (not to exceed 5 NTU)
based on a demonstration conducted by the system as described in
§141.552.
A value determined by the State (not to exceed 5 NTU) based on the
demonstration as described in §141.552.
§141.552  If my system consists of
"alternative filtration" and is required to
conduct a demonstration, What is required
of my system and how does the State
establish my turbidity limits?
  (a) If your system is required to
conduct a demonstration (see tables in
§ 141,551), your system must
demonstrate to the State, using pilot
plant studies or other means, that your
system's filtration, in combination with
disinfection treatment, consistently
achieves:
  (1) 99.9 percent removal and/or
inactivation of Giardia lamblia cysts;
  (2) 99.99 percent removal and/or
inactivation of viruses; and
  (3) 99 percent removal of
Qyptosporidium oocysts.
  (b) If the State approves your
demonstration, it will set turbidity
performance requirements that your
system must meet:
  (1) At least 95 percent of the time (not
to exceed 1 NTU);  and
  (2) That your system must not exceed
at any time (not to exceed 5 NTU).
§ 141.553  If my system practices lime
softening, is there any special provision
regarding my combined filter effluent?

  If your system practices lime
softening, you may acidify
representative combined filter effluent
turbidity samples prior to analysis using
a protocol approved by the State.

Individual Filter Turbidity
Requirements

§ 141.560  Is my system subject to
individual filter turbidity requirements?
  If your system is a subpart H system
serving fewer than 10,000 people and
utilizing conventional filtration or direct
filtration, you must conduct continuous
monitoring of turbidity for each
individual filter at your system. The
following requirements apply to
individual filter turbidity monitoring:
  (a) Monitoring must be conducted
using an approved method in
§141.74(a);
                                          (b) Calibration of turbidimeters must
                                        be conducted using procedures
                                        specified by the manufacturer;
                                          (c) Results of individual filter
                                        turbidity monitoring must be recorded
                                        every 15 minutes;
                                          (d) Monthly reporting must be
                                        completed according § 141.570; and
                                          (e) Records must be maintained
                                        according to § 141.571.

                                        § 141 .!>61  What happens if my system's
                                        turbidity monitoring equipment fails?
                                          If there is a failure in the continuous
                                        turbidity monitoring equipment, the
                                        system must conduct grab sampling
                                        every four hours in lieu of continuous
                                        monitoring until the turbidimeter is
                                        back on-line. A system has five working
                                        days to resume continuous monitoring
                                        before a violation is incurred.

                                        § 141.562  What follow-up action is my
                                        system required to take based on turbidity
                                        monitoring of individual filters?
                                          Follow-up action is required
                                        according to the following tables:
If the turbidity of an individual filter exceeds...
(a) If the turbidity of an individual filter exceeds 1 .0 NTU (in two con-
secutive recordings).
The system must...
Submit an exceptions report to the State by the 10th of the month
which includes the filter nurnber(s), corresponding date(s), and the
turbidity value(s) which exceeded 1 .0 NTU.

If an exceptions report is submitted for the same filter...
The system must...
 (b) If an exceptions report is submitted for the same filter three months
   in a row.
                     Conduct a self-assessment of the filter within 14 days of the exceed-
                      ance and report that the self assessment was conducted by the 10th
                      of the following month. The self assessment must consist of at least
                      the following components: Assessment of filter performance; devel-
                      opment of a filter profile; identification and prioritization of factors lim-
                      iting filter performance; assessment of the applicability of corrections;
                      and preparation of a filter self-assessment report.

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Federal Register/Vol.  65, No.  69/Monday, April 10, 2000/Proposed  Rules

If an
exceptions
report
is submitted
for the same
filter...
The
system
must...
(c) If an exceptions report is submitted for the same filter two months in
  a row and both months  contain exceedances of 2.0 NTU (in 2 con-
  secutive recordings).
                                          (1) Arrange to have a comprehensive performance evaluation (CPE)
                                            conducted  by the State or a third party approved by the State no
                                            later than 30 days following the exceedance and have the evaluation
                                            completed and submitted to the State no later than 90 days following
                                            the exceedance, Unless—
                                          (2) A CPE has been completed by the State or a third party approved
                                            by the State within the 12 prior months or the system and State are
                                            jointly participating in an ongoing Comprehensive Technical Assist-
                                            ance (CTA) project at the system.
§ 141.563  My system practices lime
softening. Is there any special provision
regarding my individual filter turbidity
monitoring?

  If your system utilizes lime softening,
you may apply to the State for
alternative turbidity exceedance levels
for the levels specified in the table in
§ 141.562. You must be able to
demonstrate to the State that higher
                      turbidity levels in individual filters are
                      due to lime carryover only, and not due
                      to degraded filter performance.

                      Reporting and Recordkeeping
                      Requirements

                      § 141.570  What does subpart T require that
                      my system report to the State?
                       This subpart T requires your system
                      to report several items to the State. The
following table describes the items
which must be reported and the
frequency of reporting. Your system is
required to report the information
described below, if it is subject to the
specific requirement shown in the first
column.
Corresponding requirement
(a) Combined Filter Effluent Re-
quirements.


(b) Individual Filter Turbidity Re-
quirements.






(c) Disinfection Profiling 	

(d) Disinfection Benchmarking 	

Description of information to report
(1)The total number of filtered water turbidity measurements taken
during the month.
(2) The number and percentage of filtered water turbidity measure-
ments taken during the month which are greater than your sys-
tem's required 95th percentile limit.
(3) The date and value of any turbidity measurements taken during
the month which exceed the maximum turbidity value for your fil-
tration system.
(1) That your system conducted individual filter turbidity monitoring
during the month.
(2) The filter number(s), corresponding date(s), and the turbidity
value(s) which exceeded 1 .0 NTU during the month..
(3) That a self assessment was conducted within 14 days of the date
it was triggered.
(4) That a CPE is required and the date that it was triggered 	

(5) Copy of completed CPE report 	

(1) Results of applicability monitoring which show TTHM levels
<0.064 mg/l and HAAS levels <0.048 mg/l. (Only if your system
wishes to forgo profiling) or that your system has begun disinfec-
tion profiling.

tern's disinfection profile for Giardia lamblia (and, if necessary, vi-
ruses) and disinfection benchmark, and an analysis of how the
proposed change will affect the current levels of disinfection.
Frequency
By the 10th of the following
month.
By the 10th of the following
month.
(i) Within 24 hours of exceedance
and
(ii) By the 10th of the following
month.
By the 10th of the following
month.
By the 10th of the following month
only if —
(ii) 2 consecutive values exceeded
1.0 NTU.
(i) By the 10th of the following
month (or 14 days after the self
assessment was triggered only
if the self assessment was trig-
gered during the last four days
of the month) only if —
(ii) A self-assessment is required.
(i) By the 10th of the following
month only if —
(ii) A CPE is required.
Within 90 days after the CPE was
triggered.


. ' .
ering a significant change to its
disinfection practice.

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                                                                    19149
§141.571  What records does subpart T
require my system to keep?
  Your system must keep several types
of records based on the requirements of
the necessary records, the length of time  subject to the specific requirement
these records must be kept, and for
which requirement the records pertain.
Your system is required to maintain
subpart T. The following table describes   records described in this table, if it is
shown in the first column. For example,
if your system uses slow sand filtration,
you would not be required to keep
individual filter turbidity records:
Corresponding requirement

qulrements.
(b) Disinfection Profiling 	
(c) Disinfection Benchmarking 	
(d) Covered Reservoirs 	 	

Description of necessary records
Results of individual filter monitoring 	 	 	

Results of Profile (including raw data and analysis) 	
Benchmark (including raw data and analysis) 	
Date of construction for all uncovered finished water reservoirs uti-
lized by your system.
Duration of time records must be
kept
At least 3 years.

Indefinitely.
Indefinitely.
Indefinitely.

PART 142—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
IMPLEMENTATION
  13. The authority citation for Part 142
continues to read as follows:
  Authority: 42 U.S.C. 300f, 300g-l, 300g-2,
300g-3, 300g~4, 300g-5, 300g-6, 300J-4,
300J-9, and 300J-11.
  14. Section 142.14 is amended by
revising paragraphs (a)(3), (a)(4)(i),
(a)(4)(ii) introductory text, and (a}(7) to
read as follows:
§ 142.14  Records kept by States.
  fa)* *  *
  (3) Records of turbidity measurements
must be kept for not less than one year.
The information retained must be set
forth in a form which makes possible
comparison with the limits specified in
§§141.71,141.73,141.173 and 141.175,
141.550-141.553 and 141.560-141.563
of this chapter. Until June 29,1993, for
any public water system which is
providing filtration treatment and until
December 30,1991, for any public water
system not providing filtration
treatment and not required by the State
to provide filtration treatment, records
kept must be set forth in a form which
makes possible comparison with the
limits contained in § 141.13  of this
chapter.
 *****
   (4)(i) Records of disinfectant residual
measurements and other parameters
necessary to document disinfection
effectiveness in accordance with
 §§ 141.72 and 141.74 of this chapter and
 the reporting requirements of §§ 141.75,
 141.175, and 141.570, of this chapter
 must be kept for not less than one year.
   (ii) Records of decisions made on a
 system-by-system and case-by-case basis
 under provisions of part 141, subpart H,
 subpart P, or subpart T of this chapter,
 must be made in writing and kept at the
 State.
  (7) Any decisions made pursuant to
the provisions of part 141, subpart P or
subpart T of this chapter.
  (i) Records of systems consulting with
the State concerning a modification to
disinfection practice under
§§141.172(c), 141.170(d), and 141.544
of this chapter, including the status of
the consultation or approval.
  (ii) Records of decisions that a system
using alternative filtration technologies,
as allowed under §§ 141.173(b) and
§ 141.552 of this chapter, can
consistently achieve a 99.9 percent
removal and/or inactivation of Giardia
lamblia cysts, 99.99 percent removal
and/or inactivation of viruses, and 99
percent removal of Cryptosporidium
oocysts. The decisions must include
State-set enforceable turbidity limits for
each system. A copy of the decision
must be kept until the decision is
reversed or revised. The State must
provide a copy of the decision to the
system.
  (iii) Records of systems required to do
filter self-assessment, CPE, or CCP
under the requirements of § 141.175 and
§ 141.562 of this chapter.
*****
   15. Section 142.15 is amended by
adding paragraphs (c)(6) and (c)(7) and
MM.

§ 142.15  Reports by States.
 *****
   (c)* * *
   (6) Recycle return location. A list of
all systems moving the recycle return
location prior to the point of primary
coagulant addition. The list must also
contain all the systems the State granted
 alternate recycle locations, describe the
 alternative recycle return location, and
briefly discuss the reason(s) the
 alternate recycle location was granted
 and is due [DATE 60 MONTHS AFTER
 DATE OF PUBLICATION OF FINAL
 RULE IN THE FEDERAL REGISTER].
  (7) Self assessment determination. A
list of all systems performing self
assessments must be reported to EPA.
The list must state whether individual
plants exceeded State approved
operating capacity during self
assessment monitoring and whether the
State required modification to recycle
practice. A brief description of the
modification to recycle practice
required at each plant must be provided.
If a plant exceeded State approved
operating capacity, and the State did not
require modification of recycle practice,
the State must provide a brief
explanation for this decision. Self
assessment results must be reported no
later than [DATE 54 MONTHS AFTER
DATE OF PUBLICATION OF FINAL
RULE IN THE FEDERAL REGISTER].
  (8) Direct filtration determination. A
list of all direct filtration systems
recycling within the treatment process
must be submitted to EPA. The list must
state which systems were required to
modify recycle practice and briefly
describe the modification and the
reason it was required. It must also
identify systems not required to modify
recycle practice and provide a brief
description of the reason modification
to recycle practice was not required.
The list must be submitted no later than
[DATE 54 MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER].
*****
   16. Section 142.16 is amended by
adding paragraph (b)(2)(v), (b)(2)(vi),
and (b)(2Kvii) and (i) to read as follows:

§ 142.1(5 Special primacy requirements.
 *****
   (b)* * *
   (2)* * *
   (v) The application must describe the
 criteria the State will use to determine
 alternate recycle locations for public
water systems applying to return spent
 filter backwash, thickener supernatant,

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Federal Register/Vol.  65,  No. 69/Monday, April  10,  2000/Proposed Rules
or liquids from dewatering to an
alternate location other than prior to the
point of primary coagulant addition.
  (vi) The application must describe the
criteria the State will use to determine
whether public water systems
completing self assessments are
required to modify recycle practice and
the criteria that will be used to specify
modifications to recycle practice.
  (vii) The application must describe
the criteria the State will use to
determine whether direct filtration
systems are required to change recycle
practice and the criteria that will be
used to specify changes to recycle
practice.
*****
  (i) Requirements for States to adopt
40 CFR part 141, subpart T Enhanced
Filtration and Disinfection. In addition
to the general primacy requirements
enumerated elsewhere in this part,
including the requirement that State
provisions are no less stringent than the
federal requirements, an application for
approval of a State program revision
that adopts 40 CFR part 141, subpart T
Enhanced Filtration and Disinfection,
must contain the information specified
in this paragraph;
  (1) Enforceable requirements. States
must have rules or other authority to
require systems to participate in a
Comprehensive Technical Assistance
                     (CTA) activity, the performance
                     improvement phase of the Composite
                     Correction Program (CCP). The State
                     shall determine whether a CTA must be
                     conducted based on results of a CPE
                     which indicate the potential for
                     improved performance, and a finding by
                     the State that the system is able to
                     receive and implement technical
                     assistance provided through the CTA. A
                     CPE is a thorough review and analysis
                     of a system's performance-based
                     capabilities and associated
                     administrative, operation and
                     maintenance practices. It is conducted
                     to identify factors that may be adversely
                     impacting a plant's capability to achieve
                     compliance. During the CTA phase, the
                     system must identify and systematically
                     address factors limiting performance.
                     The CTA is a combination of utilizing
                     CPE results as a basis for follow-up,
                     implementing-process control priority-
                     setting techniques and maintaining
                     long-term involvement to systematically
                     train staff and administrators.
                       (2) State practices or procedures, (i)
                     Section 141.536 of this chapter—How
                     the State will approve a method to
                     calculate the logs of inactivation for
                     viruses for a system that uses either
                     chloramines or ozone for primary
                     disinfection.
                       (ii) Section 141.544 of this chapter—
                     How the State will approve
                     modifications to disinfection practice.
  (iii) Section 141.552 of this chapter—
For filtration technologies other than
conventional filtration treatment, direct
filtration, slow sand nitration,
diatomaceous earth filtration, or
membrane filtration, how the State will
determine that a public water system
may use a filtration technology if the
PWS demonstrates to the State, using
pilot plant studies or other means, that
the alternative filtration technology (or
membrane filtration), in combination
with disinfection treatment that meets
the requirements of § 141.72(b) of this
chapter, consistently achieves 99.9
percent removal and/or inactivation of
Giardia lamblia cysts and 99.99 percent
removal and/or inactivation of viruses,
and 99 percent removal of
Cryptosporidium oocysts. For a system
that makes this demonstration, how the
State will set turbidity performance
requirements that the system must meet
95 percent of the time and that the   .
system may not exceed at any time at a
level that consistently achieves 99.9
percent removal and/or inactivation of
Giardia lamblia cysts, 99.99 percent
removal and/or inactivation of viruses,
and 99 percent removal of
Cryptosporidium oocysts.
[FR Doc. 00-8155 Filed 4-7-00; 8:45 am]
BILLING CODE 6560-50-P

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