59486 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 141 and 142

[WH–FRL–5915–4]

National Primary Drinking Water

Regulations: Interim Enhanced Surface

Water Treatment Rule Notice of Data

Availability

AGENCY: U.S. Environmental Protection

Agency (USEPA).

ACTION: Notice of Data Availability;

request for comments; reopening of

comment period.

SUMMARY: USEPA proposed in 1994 to

amend the Surface Water Treatment

Rule to provide additional protection

against disease-causing organisms

(pathogens) in drinking water (59 FR

38832: July 29, 1994). This Notice of

Data Availability summarizes the 1994

proposal; describes new data and

information that the Agency has

obtained and analyses that have been

developed since the proposal; provides

information concerning

recommendations of the MicrobialDisinfectants/Disinfection Byproducts

(M-DBP) Advisory Committee (chartered

in February 1997 under the Federal

Advisory Committee Act) on key issues

related to the proposal; and requests

comment on these recommendations as

well as on other regulatory implications

that flow from the new data and

information. USEPA solicits comment

on all aspects of this Notice and the

supporting record. The Agency also

solicits additional data and information

that may be relevant to the issues

discussed in the Notice. USEPA is

particularly interested in public

comment on the Committee’s

recommendations and whether the

Agency should reflect these

recommendations in the final rule. In

addition, USEPA is hereby providing

notice that the Agency is re-opening the

comment period for the 1994 proposal

for 90 days beginning on the date of

publication of today’s Notice in the

Federal Register. USEPA also requests

that any information, data or views

submitted to the Agency since the close

of the comment period on the 1994

proposal that members of the public

would like the Agency to consider as

part of the final rule development

process be resubmitted during this

current 90-day comment period unless

already in the underlying record in the

Docket for this Notice.

The Interim Enhanced Surface Water

Treatment Rule (IESWTR) would apply

to surface water systems serving 10,000

or more people. USEPA intends to

promulgate the final rule in November

1998 as required by the 1996

Amendments to the Safe Drinking Water

Act. The Agency plans subsequently to

address surface water systems serving

fewer than 10,000 people as part of a

‘‘long-term’’ Enhanced Surface Water

Treatment Rule which may also include

additional refinements for larger

systems.

Key issues related to the IESWTR that

are addressed in this Notice include the

establishment of a Maximum

Contaminant Level Goal for

Cryptosporidium; removal of

Cryptosporidium by filtration; revised

turbidity provisions; disinfection

benchmark provisions to assure

continued levels of microbial protection

while facilities take the necessary steps

to comply with new disinfection

byproduct standards; sanitary surveys;

inclusion of Cryptosporidium in the

definition of ground water under the

direct influence of surface water; and

inclusion of Cryptosporidium in the

watershed control requirements for

unfiltered public water systems. Other

issues that are discussed include

inactivation of Cryptosporidium, viruses

and Giardia lamblia; uncovered finished

water reservoirs; cross connection

control; and recycling of filter backwash

water and filter-to-waste.

Today’s Federal Register also

contains a related Notice of Data

Availability for the Stage 1

Disinfectants/Disinfection Byproducts

Rule (DBPR). USEPA proposed this rule

at the same time as the IESWTR and

plans to promulgate it along with the

IESWTR in November 1998.

DATES: Comments should be postmarked

or delivered by hand on or before

February 3, 1998. Comments must be

received or post-marked by midnight

February 3, 1998.

ADDRESSES: Send written comments to

IESWTR NODA Docket Clerk, Water

Docket (MC-4101); U.S. Environmental

Protection Agency; 401 M Street, SW;

Washington, DC 20460. Please submit

an original and three copies of your

comments and enclosures (including

references). If you wish to hand-deliver

your comments, please call the Docket

between 9:00 a.m. and 4 p.m., Monday

through Friday, excluding legal

holidays, to obtain the room number for

the Docket. Comments may be

submitted electronically to owdocket@epamail.epa.gov.

FOR FURTHER INFORMATION, CONTACT: The

Safe Drinking Water Hotline, Telephone

(800) 426–4791. The Safe Drinking

Water Hotline is open Monday through

Friday, excluding Federal holidays,

from 9:00 am to 5:30 pm Eastern Time.

For technical inquiries, contact

Elizabeth Corr or Paul S. Berger,

Ph.D.(Microbiology), Office of Ground

Water and Drinking Water (MC 4607),

U.S. Environmental Protection Agency,

401 M Street SW, Washington DC

20460; telephone (202) 260–8907 (Corr)

or (202) 260–3039 (Berger).

Regional Contacts

Region I. Kevin Reilly, Water Supply

Section, JFK Federal Bldg., Room 203,

Boston, MA 02203, (617) 565–3616

II. Michael Lowy, Water Supply Section,

290 Broadway, 24th Floor, New York,

NY 10007–1866, (212) 637–3830

III. Jason Gambatese, Drinking Water

Section (3WM41), 841 Chestnut

Building, Philadelphia, PA 19107,

(215) 566–5759

IV. David Parker, Water Supply Section,

345 Courtland Street, Atlanta, GA

30365, (404)562–9460

V. Kimberly Harris (micro), Miguel Del

Toral (DBP), Water Supply Section, 77

W. Jackson Blvd., Chicago, IL 60604,

(312) 886–4239 (Harris), (312) 886–

5253 (Del Toral)

VI. Blake L. Atkins, Team Leader, Water

Supply Section, 1445 Ross Avenue,

Dallas, TX 75202, (214) 665–2297

VII. Stan Calow, State Programs Section,

726 Minnesota Ave., Kansas City, KS

66101, (913) 551–7410

VIII. Bob Clement, Public Water Supply

Section (8WM-DW), 999 18th Street,

Suite 500, Denver, CO 80202–2466,

(303) 312–6653

IX. Bruce Macler, Water Supply Section,

75 Hawthorne Street, San Francisco,

CA 94105, (415) 744–1884

X. Wendy Marshall, Drinking Water

Unit, 1200 Sixth Avenue (OW–136),

Seattle, WA 98101, (206) 553–1890.

SUPPLEMENTARY INFORMATION:

Regulated entities. Entities potentially

regulated by the IESWTR are public

water systems that use surface water

and serve at least 10,000 people.

Regulated categories and entities

include:

Category Examples of regulated entities

Public Water System ................................................................ PWSs that use surface water and serve at least 10,000 people.

State Governments ................................................................... State government offices that regulate drinking water.
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59487

This table is not intended to be

exhaustive, but rather provides a guide

for readers regarding entities likely to be

regulated by the IESWTR. This table

lists the types of entities that USEPA is

now aware could potentially be

regulated by the rule. Other types of

entities not listed in this table could

also be regulated. To determine whether

your facility may be regulated by this

action, you should carefully examine

the applicability criteria outlined under

Alternatives A and B in § 141.70 of the

proposed rule (59 FR 38832, July 29,

1994).

If you have questions regarding the

applicability of the IESWTR to a

particular entity, contact one of the

persons listed in the preceding FOR

FURTHER INFORMATION CONTACT section.

Additional Information for

Commenters. The Agency requests that

commenters follow the following

format: type or print comments in ink,

and cite, where possible, the

paragraph(s) in this Notice to which

each comment refers. Commenters

should use a separate paragraph for each

method or issue discussed. Electronic

comments must be submitted as a

WP5.1 or WP6.1 file or as an ASCII file

avoiding the use of special characters

and any form of name or title of the

Federal Register. Comments and data

will also be accepted on disks in

WordPerfect in 5.1 or WP6.1 or ASCII

file format. Electronic comments on this

Notice may be filed online at many

Federal Depository Libraries.

Commenters who want EPA to

acknowledge receipt of their comments

should include a self-addressed,

stamped envelope. No facsimiles (faxes)

will be accepted.

Availability of Record. The record for

this Notice, which includes supporting

documentation as well as printed, paper

versions of electronic comments, is

available for inspection from 9 to 4 p.m.,

Monday through Friday, excluding legal

holidays at the Water Docket, U.S. EPA

Headquarters, 401 M. St., S.W.

Washington, D.C. 20460. For access to

docket materials, please call 202/260–

3027 to schedule an appointment and

obtain the room number.

Copyright Permission. Supporting

documentation reprinted in this

document from copyrighted material

may be reproduced or republished

without restriction in accordance with 1

CFR 2.6.

List of Abbreviations Used in This

Document

ASCE—American Society of Civil

Engineers

ASTM—American Society for Testing

Materials

AWWA—American Water Works

Association

C—the residual concentration of

disinfectant, mg/L

CDC—Centers for Disease Control

CFE—Combined Filter Effluent

CFR—Code of Federal Regulations

CPE—Comprehensive Performance

Evaluation

CT—the residual concentration of

disinfectant multiplied by the contact

time

DOC—dissolved organic carbon

ESWTR—Enhanced Surface Water

Treatment Rule

FACA—Federal Advisory Committee

Act

gpm/sf—gallons per minute per square

foot

HAA5—Haloacetic acids

(monochloroacetic, dichloroacetic,

trichloroacetic, monobromoacetic,

and dibromoacetic acids)

HAV—hepatitis A virus

hrs—hours

ICR—Information Collection Rule

IESWTR—Interim Enhanced Surface

Water Treatment Rule

IFA—Individual Filter Assessment

IFE—Individual Filter Effluent

ISO—International Standards

Organization

k—the pseudo first-order reaction rate

constant

L—liter

Log Inactivation—logarithm of (No/NT)

Log—logarithm (common, base 10)

LTESWTR—Long Term Enhanced

Surface Water Treatment Rule

MCL—Maximum Contaminant Level

MCLG—Maximum Contaminant Level

Goal

M-DBP—Microbial and Disinfectants/

Disinfection Byproducts

mg/L—milligram per liter

mg-min/L—milligram minutes per liter

MMWR—Morbidity and Mortality

Weekly Report

mW-s/cm2—milliwatt seconds per

square centimeter

No—the initial viable concentration of

microorganisms

NPDWR—National Primary Drinking

Water Regulation

NT—the concentration of surviving

microorganisms at time T

NTU—nephelometric turbidity unit

°C—degrees centigrade

PE—Performance Evaluation

pH—negative logarithm of the effective

hydrogen-ion concentration

PV1—poliovirus 1

PV3—poliovirus 3

PWS—Public Water System

RSD—Relative Standard Deviation

SAB—Science Advisory Board

SDWA—Safe Drinking Water Act

T—the contact time, second or minute

TOC—total organic carbon

TTHM—Total Trihalomethanes

TWG—Technical Work Group

UV—ultraviolet

x—log removal Reduction by 1/10**x

Table of Contents

I. Introduction and Background

A. Existing regulations

1. Surface Water Treatment Rule

2. Total Trihalomethane MCL

3. Total Coliform Rule

4. Information Collection Rule

B. Public health concerns to be addressed

C. Statutory provisions

1. SDWA and 1986 provisions

2. Changes to initial provisions and new

mandates

D. Regulatory negotiation process

E. Information Collection Rule

F. Formation of 1997 Federal Advisory

Committee

G. Overview of 1994 proposed IESWTR

1. Summary of major elements

2. Alternative treatment requirements

3. Possible supplemental treatment

requirements

a. uncovered finished water reservoirs

b. cross connection control program

c. State notification of high turbidity levels

4. Other related issues

II. New Information and Key Issues To Be

Addressed

A. MCLG for Cryptosporidium

1. Summary of 1994 proposal and public

comments

2. New data and perspectives

3. Advisory Committee recommendations

and related issues

B. Removal of Cryptosporidium by filtration

1. Summary of 1994 proposal and public

comments

2. New data and perspectives

a. rapid granular filtration

b. other filtration technologies

c. multiple barrier approach

3. Advisory Committee recommendations

and related issues

C. Turbidity control

1. Summary of 1994 proposal as it relates

to turbidity issues and public comments

2. New data and perspectives

a. 95th percentile and maximum turbidity

levels of composite filtered water

b. individual filter performance

c. turbidity measurement

3. Advisory Committee recommendations

and related issues

D. Disinfection benchmark for Stage I DBP

MCLs

1. Applicability

2. Developing the profile and benchmark

3. State review

4. Guidance

5. Request for public comment

E. Definition of ground water under direct

influence of surface water (GWUDI)—

inclusion of Cryptosporidium in the

definition

1. Summary of 1994 proposal and public

comments

2. Overview of existing guidance

3. Summary of new data and perspectives
59488 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

4. Request for public comment

F. Inclusion of Cryptosporidium in watershed

control requirements

1. Summary of 1994 proposal and public

comments

2. Overview of existing guidance

3. Summary of new data and perspectives

G. Sanitary survey requirements

1. Summary of 1994 proposal

2. Overview of existing regulations and

guidance

3. New developments

4. Advisory Committee recommendations

and related issues

H. Covered finished water reservoirs

1. Summary of 1994 proposal and public

comments

2. Overview of existing information

3. Request for public comment

I. Cross connection control program

1. Summary of 1994 proposal and public

comments

2. Overview of existing information

3. Request for public comment

J. Recycling filter backwash water and

filtering to waste

1. Filter backwash recycle configuration

2. State drinking water regulations

3. Literature overview of standards of

practice

4. Filter-to-waste

5. Request for public comment

K. Certification criteria for water plant

operators

L. Regulatory compliance schedule and other

compliance-related issues

1. Regulatory compliance schedule

2. Compliance violations and State

primacy obligations

3. Compliance with current regulations

M. Disinfection studies

1. New Giardia inactivation studies at high

pH levels

2. Effectiveness of different disinfectants

on Cryptosporidium

3. New virus inactivation studies

III. Economic Analysis of M-DBP Advisory

Committee Recommendations

A. Overview of RIA for proposed rule

B. What’s changed since proposed rule

C. Summary of cost analysis

1. Total national costs

2. Household costs

D. Cost of turbidity performance criteria &

associated monitoring

1. System level impact analysis

2. National impact analysis

a. decision tree

b. utility costs

c. State costs

E. Disinfection benchmark

1. Decision tree

2. Utility costs

3. State costs

F. Sanitary surveys

G. Summary of benefits analysis

IV. National Technology Transfer and

Advancement Act

I. Introduction and Background

A. Existing Regulations

1. Surface Water Treatment Rule

Under the Surface Water Treatment

Rule (SWTR)(54 FR 27486, June 29,

1989), USEPA set maximum

contaminant level goals of zero for

Giardia lamblia, viruses, and Legionella;

and promulgated national primary

drinking water regulations for all public

water systems (PWSs) using surface

water sources or ground water sources

under the direct influence of surface

water. The SWTR includes treatment

technique requirements for filtered and

unfiltered systems that are intended to

protect against the adverse health effects

of exposure to Giardia lamblia, viruses,

and Legionella, as well as many other

pathogenic organisms. Briefly, those

requirements include (1) removal or

inactivation of 3 logs (99.9%) for

Giardia and 4 logs (99.99%) for viruses;

(2) combined filter effluent performance

of 5 NTU as a maximum and 0.5 NTU

at 95th percentile monthly, based on 4-

hour monitoring for treatment plants

using conventional treatment or direct

filtration (with separate standards for

other filtration technologies); and (3)

watershed protection and other

requirements for unfiltered systems.

2. Total Trihalomethane MCL

USEPA set an interim Maximum

Contaminant Level (MCL) for total

trihalomethanes (TTHM) of 0.10 mg/l as

an annual average in November 1979

(44 FR 68624). This standard was based

on the need to balance the requirement

for continued disinfection of water to

reduce exposure to pathogenic

microorganisms while simultaneously

lowering exposure to disinfection

byproducts which might be

carcinogenic to humans.

The interim TTHM standard only

applies to any PWSs (surface water and/

or ground water) serving at least 10,000

people that add a disinfectant to the

drinking water during any part of the

treatment process. At their discretion,

States may extend coverage to smaller

PWSs. However, most States have not

exercised this option. About 80 percent

of the PWSs, serving populations of less

than 10,000, are served by ground water

that is generally low in THM precursor

content (USEPA, 1979) and which

would be expected to have low TTHM

levels even if they disinfect.

3. Total Coliform Rule

The Total Coliform Rule (54 FR

27544; June 29, 1989), revised in June

1989 and effective on December 31,

1990 applies to all public water systems

(USEPA, 1989b). This regulation sets

compliance with the Maximum

Contaminant Level (MCL) for total

coliforms as follows. For systems that

collect 40 or more samples per month,

no more than 5.0% of the samples may

be total coliform-positive; for those that

collect fewer than 40 samples, only one

sample may be total coliform-positive. If

a system exceeds the MCL for a month,

it must notify the public using

mandatory language developed by the

USEPA. The required monitoring

frequency for a system ranges from 480

samples per month for the largest

systems to once annually for certain of

the smallest systems. All systems must

have a written plan identifying where

samples are to be collected. In addition,

systems are required to conduct repeat

sampling after a positive sample.

The Total Coliform Rule also requires

each system that collects fewer than five

samples per month to have the system

inspected every 5 years (10 years for

certain types of systems using only

protected and disinfected ground

water.) This on-site inspection (referred

to as a sanitary survey) must be

performed by the State or by an agent

approved by the State.

4. Information Collection Rule

The Information Collection Rule (ICR)

is a monitoring and data reporting rule

that was promulgated on May 14, 1996

(61 FR 24354) (USEPA, 1996b). The

purpose of the ICR is to collect

occurrence and treatment information to

evaluate the need for possible changes

to the current Surface Water Treatment

Rule and existing microbial treatment

practices and to evaluate the need for

future regulation for disinfectants and

DBPs. The ICR will provide USEPA

with additional information on the

national occurrence in drinking water of

(1) chemical byproducts that form when

disinfectants used for microbial control

react with compounds already present

in source water and (2) disease-causing

microorganisms, including

Cryptosporidium, Giardia, and viruses.

The ICR will also collect engineering

data on how PWSs currently control

such contaminants. This information is

being collected because the regulatory

negotiation on disinfectants and DBPs

concluded that additional information

was needed to assess the potential

health problem created by the presence

of DBPs and pathogens in drinking

water and to assess the extent and

severity of risk in order to make sound

regulatory and public health decisions.

The ICR will also provide information to

support regulatory impact analyses for

various regulatory options, and to help

develop monitoring strategies for cost

effectively implementing regulations.

B. Public Health Concerns To Be

Addressed

In 1990, USEPA’s Science Advisory

Board (SAB), an independent panel of

experts established by Congress, cited
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59489

drinking water contamination as one of

the most important environmental risks

and indicated that disease-causing

microbial contaminants (i.e., bacteria,

protozoa and viruses) are probably the

greatest remaining health risk

management challenge for drinking

water suppliers (USEPA/SAB 1990).

This view was prompted by the SAB’s

concern about the number of waterborne

disease outbreaks in the U.S. Between

1980 and 1994, 379 waterborne disease

outbreaks were reported, with over

500,000 cases of disease. During this

period, a number of agents were

implicated as the cause, including

protozoa, viruses and bacteria, as well

as several chemicals. Most of the cases

(but not outbreaks) were associated with

surface water, and specifically with a

single outbreak of cryptosporidiosis in

Milwaukee (over 400,000 cases) (Craun,

Pers. Comm. 1997a).

The number of waterborne disease

outbreaks and cases is, however,

probably much greater than that

recorded because the vast majority of

waterborne disease is probably not

reported. Few States have an active

outbreak surveillance program and

disease outbreaks are often not

recognized in a community or, if

recognized, are not traced to the

drinking water source. This situation is

complicated by the fact that the vast

majority of people experiencing

gastrointestinal illness (predominantly

diarrhea) do not seek medical attention.

For those who do, physicians generally

cannot attribute gastrointestinal illness

to any specific origin such as a drinking

water source. An unknown but probably

significant portion of waterborne

disease is endemic, i.e., not associated

with an outbreak, and thus is even more

difficult to recognize.

One of the key regulations USEPA has

developed and implemented to counter

pathogens in drinking water is the

SWTR. Among its provisions, the rule

requires that a public water system have

sufficient treatment to reduce the source

water concentration of Giardia and

viruses by at least 99.9% (3 logs) and

99.99% (4 logs), respectively.

The goal of the SWTR is to reduce risk

to less than one infection per year per

10,000 people (10-4). However, one of

the SWTR’s shortcomings is that the

source waters of some systems have

high pathogen concentrations that,

when reduced by the levels required

under the rule, still may not meet a

common health goal (e.g., 10-4).

Another shortcoming of the SWTR is

that the rule does not specifically

control for the protozoan

Cryptosporidium. The first report of a

recognized outbreak caused by

Cryptosporidium was published during

the development of the SWTR

(D’Antonio et al., 1985). Other outbreaks

caused by this pathogen have since been

reported both in the United States and

other countries (Smith et al.,1988; Hayes

et al., 1989; Levine and Craun, 1990;

Moore et al., 1993; Craun, 1993). A

particular public health challenge is that

simply increasing existing disinfection

levels above those most commonly

practiced in the United States today

does not appear to be an effective

strategy for controlling

Cryptosporidium.

In addition to these issues, there is

another potentially counter-balancing

public health concern. The disinfectants

used to control microbial pathogens

may produce toxic or carcinogenic

disinfection byproducts (DBPs) when

they react with organic chemicals in the

source water. Thus, an important

question facing water supply

professionals is how to minimize the

risk from both microbial pathogens and

DBPs simultaneously.

At the time the SWTR was

promulgated, USEPA had limited data

concerning Giardia and

Cryptosporidium occurrence in source

waters and treatment efficiencies. The 3-

log removal/inactivation of Giardia

lamblia and 4-log removal/inactivation

of enteric viruses required by the SWTR

were developed to provide protection

from most pathogens in source waters.

However, additional data has become

available since promulgation of the

SWTR concerning source water

occurrence and treatment efficiencies

for Giardia, as well as for

Cryptosporidium (LeChevallier et al.

1991 a,b). A major concern is that if

systems currently provide four or more

logs of removal/inactivation for Giardia,

such systems might reduce existing

levels of disinfection to more easily

meet new DBP regulations, and thus

only marginally meet the three-log

removal/inactivation requirement for

Giardia lamblia specified in the current

SWTR. Depending upon source water

Giardia concentrations, such treatment

changes could lead to significant

increases in microbial risk (Regli et al.,

1993; Grubbs et al., 1992; USEPA,

1994b).

C. Statutory Provisions

1. SDWA and 1986 Provisions

The Safe Drinking Water Act (SDWA

or the Act), as amended in 1986,

requires USEPA to publish a ‘‘maximum

contaminant level goal’’ (MCLG) for

each contaminant which, in the

judgement of the USEPA Administrator,

‘‘may have any adverse effect on the

health of persons and which are known

or anticipated to occur in public water

systems’’ (Section 1412(b)(3)(A)).

MCLGs are to be set at a level at which

‘‘no known or anticipated adverse effect

on the health of persons occur and

which allows an adequate margin of

safety’’ (Section 1412(b)(4)).

The Act also requires that at the same

time USEPA publishes an MCLG, which

is a non-enforceable health goal, it also

must publish a National Primary

Drinking Water Regulation (NPDWR)

that specifies either a maximum

contaminant level (MCL) or treatment

technique (Sections 1401(1) and

1412(a)(3)). USEPA is authorized to

promulgate a NPDWR ‘‘that requires the

use of a treatment technique in lieu of

establishing a MCL,’’ if the Agency finds

that ‘‘it is not economically or

technologically feasible to ascertain the

level of the contaminant’’.

Section 1414 (c) of the Act requires

each owner or operator of a public water

system to give notice to the persons

served by the system of any failure to

comply with an MCL or treatment

technique requirement of, or testing

procedure prescribed by, a NPDWR and

any failure to perform monitoring

required by section 1445 of the Act.

Section 1412(b)(7)(C) of the SDWA

requires the USEPA Administrator to

publish a NPDWR ‘‘specifying criteria

under which filtration (including

coagulation and sedimentation, as

appropriate) is required as a treatment

technique for public water systems

supplied by surface water sources’’. In

establishing these criteria, USEPA is

required to consider ‘‘the quality of

source waters, protection afforded by

watershed management, treatment

practices (such as disinfection and

length of water storage) and other

factors relevant to protection of health’’.

This section of the Act also requires

USEPA to promulgate a NPDWR

requiring disinfection as a treatment

technique for all public water systems

and a rule specifying criteria by which

variances to this requirement may be

granted.

2. Changes to Initial Provisions and New

Mandates

In 1996, Congress reauthorized the

Safe Drinking Water Act. Several of the

1986 provisions discussed above were

renumbered and augmented with

additional language, while other

sections mandate new drinking water

requirements. These modifications, as

well as new provisions, are detailed

below.

As part of the 1996 amendments to

the Safe Drinking Water Act (the

Amendments), USEPA’s general
59490 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

authority to set a MCLG and NPDWR

was modified to apply to contaminants

that may ‘‘have an adverse effect on the

health of persons’’, that are ‘‘known to

occur or there is a substantial likelihood

that the contaminant will occur in

public water systems with a frequency

and at levels of public health concern’’,

and for which ‘‘in the sole judgement of

the Administrator, regulation of such

contaminant presents a meaningful

opportunity for health risk reduction for

persons served by public water systems’

(1986 SDWA Section 1412 (b)(3)(A)

stricken and amended with

1412(b)(1)(A)).

The Amendments also require that

USEPA, when proposing a NPDWR that

includes an MCL or treatment

technique, publish and seek public

comment on health risk reduction and

cost analyses. The Amendments also

require USEPA to take into

consideration the effects of

contaminants upon sensitive

subpopulations (i.e. infants, children,

pregnant women, the elderly, and

individuals with a history of serious

illness), and other relevant factors.

(Section 1412 (b)(3)(C)).

The 1996 Amendments also newly

require USEPA to promulgate an Interim

Enhanced SWTR and a Stage I

Disinfectants and Disinfection

Byproducts Rule by November 1998. In

addition, the 1996 Amendments require

USEPA to promulgate a Final Enhanced

SWTR and a Stage 2 Disinfection

Byproducts Rule by November 2000 and

May 2002, respectively (Section

1412(b)(2)(C)).

Under the Amendments of 1996,

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)(1)(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 . . .’’.

D. Regulatory Negotiation Process

In 1992 USEPA initiated a negotiated

rulemaking to develop a disinfectants/

disinfection byproducts rule. The

negotiators included representatives of

State and local health and regulatory

agencies, public water systems, elected

officials, consumer groups and

environmental groups. The Committee

met from November 1992 through June

1993.

Early in the process, the negotiators

agreed that large amounts of information

necessary to understand how to

optimize the use of disinfectants to

concurrently minimize microbial and

DBP risk on a plant-specific basis were

unavailable. Nevertheless, the

Committee agreed that USEPA propose

a disinfectants/disinfection byproducts

rule to extend coverage to all

community and nontransient

noncommunity water systems that use

disinfectants. This rule proposed to

reduce the current TTHM MCL, regulate

additional disinfection byproducts, set

limits for the use of disinfectants, and

reduce the level of organic compounds

in the source water that may react with

disinfectants to form byproducts.

One of the major goals addressed by

the Committee was to develop an

approach that would reduce the level of

exposure from disinfectants and DBPs

without undermining the control of

microbial pathogens. The intention was

to ensure that drinking water is

microbiologically safe at the limits set

for disinfectants and DBPs and that

these chemicals do not pose an

unacceptable risk at these limits.

Following months of intensive

discussions and technical analysis, the

Committee recommended the

development of three sets of rules: a

two-staged Disinfectants/Disinfection

Byproduct Rule (proposal: 59 FR 38668,

July 29, 1994) (USEPA, 1994a), an

‘‘interim’’ ESWTR (proposal: 59 FR

38832, July 29, 1994) (USEPA, 1994b),

and an Information Collection rule

(proposal: 59 FR 6332, February 10,

1994) (USEPA, 1994c). The IESWTR

would only apply to systems serving

10,000 people or more. The Committee

agreed that a ‘‘long-term’’ ESWTR

(LTESWTR) would be needed for

systems serving fewer than 10,000

people when the results of more

research and water quality monitoring

became available. The LTESWTR could

also include additional refinements for

larger systems.

The approach in developing these

proposals considered the constraints of

simultaneously treating water to control

for both microbial contaminants and

DBPs. As part of this effort, the

Negotiating Committee concluded that

the SWTR may need to be revised to

address health risk from high densities

of pathogens in poorer quality source

waters and from the protozoan,

Cryptosporidium. The Committee also

agreed that the schedules for IESWTR

and LTESWTR should be ‘‘linked’’ to

the schedule for the Stage 1 DBP Rule

to assure simultaneous compliance and

a balanced risk-risk based

implementation. The Committee agreed

that additional information on health

risk, occurrence, treatment technologies,

and analytical methods needed to be

developed in order to better understand

the risk-risk tradeoff, and how to

accomplish an overall reduction in risk.

Finally the Negotiating Committee

agreed that to develop a reasonable set

of rules and to understand more fully

the limitations of the current SWTR,

additional field data were critical. Thus,

a key component of the regulation

negotiation agreement was the

promulgation of the Information

Collection Rule (ICR) noted above and

described in more detail below.

E. Information Collection Rule

As stated above, the ICR established

monitoring and data reporting

requirements for large public water

systems serving populations over

100,000. About 350 PWSs operating 500

treatment plants are involved in the data

collection effort. Under the ICR, these

PWSs monitor their source water for

bacteria, viruses, and protozoa (surface

water sources only); water quality

factors affecting DBP formation; and

DBPs within the treatment plant and in

the distribution system. In addition,

PWSs must provide operating data and

a description of their treatment plan

design. Finally, a subset of PWSs

perform treatment studies, using either

granular activated carbon or membrane

processes, to evaluate DBP precursor

removal. Monitoring for treatment study

applicability began in September 1996.

The remaining occurrence monitoring

began in July 1997.

The initial intent of the ICR was to

collect monitoring data and other

information for use in developing the

Stage 2 DBPR and IESWTR and to

estimate national costs for various

treatment options. However, because of

delays in promulgating the ICR and

technical difficulties associated with

laboratory approval and review of

facility sampling plans, most ICR

monitoring did not begin until July 1,

1997. As a result of this delay and the

new Stage 1 DBPR and IESWTR

deadlines specified in the 1996 SDWA

amendments, ICR data will not be

available for analysis in connection with

these rules. In place of the ICR data, the

Agency has worked with stakeholders to

identify additional data developed since

1994 that can be used in components of

these rules. USEPA intends to continue

to work with stakeholders in analyzing

and using the comprehensive ICR data

and research for developing subsequent

revisions to the SWTR and the Stage 2

DBP Rule.

F. Formation of 1997 Federal Advisory

Committee

In May 1996, the Agency initiated a

series of public informational meetings

to exchange information on issues
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59491

related to microbial and disinfectants/

disinfection byproducts regulations. To

help meet the deadlines for the IESWTR

and Stage 1 DBPR established by

Congress in the 1996 SDWA

Amendments and to maximize

stakeholder participation, the Agency

established the Microbial and

Disinfectants/Disinfection Byproducts

(M-DBP) Advisory Committee under the

Federal Advisory Committee Act

(FACA) on February 12, 1997, to collect,

share, and analyze new information and

data, as well as to build consensus on

the regulatory implications of this new

information. The Committee consists of

17 members representing USEPA, State

and local public health and regulatory

agencies, local elected officials, drinking

water suppliers, chemical and

equipment manufacturers, and public

interest groups.

The Committee met five times, in

March through July 1997, to discuss

issues related to the IESWTR and Stage

1 DBPR. Technical support for these

discussions was provided by a

Technical Work Group (TWG)

established by the Committee at its first

meeting in March 1997. The

Committee’s activities resulted in the

collection, development, evaluation,

and presentation of substantial new data

and information related to key elements

of both proposed rules. The Committee

reached agreement on the following

major issues discussed in this Notice

and the Notice for the Stage 1 DBPR

published elsewhere in today’s Federal

Register: (1) MCLs for TTHMs, HAA5

and bromate; (2) requirements for

enhanced coagulation and enhanced

softening (as part of DBP control); (3)

microbial benchmarking/profiling to

provide a methodology and process by

which a PWS and the State, working

together, assure that there will be no

significant reduction in microbial

protection as the result of modifying

disinfection practices in order to meet

MCLs for TTHM and HAA5; (4)

disinfection credit; (5) turbidity; (6)

Cryptosporidium MCLG; (7) removal of

Cryptosporidium; (8) role of

Cryptosporidium inactivation as part of

a multiple barrier concept and (9)

sanitary surveys. The Committee’s

recommendations to USEPA on these

issues were set forth in an Agreement In

Principle document dated July 15, 1997.

This document is included with this

notice as Appendix 1.

G. Overview of IESWTR 1994 Proposal

1. Summary of Major Elements

As part of the IESWTR July 29, 1994,

Federal Register notice (59 FR 38832),

USEPA proposed to revise the SWTR to

provide additional protection against

pathogens in drinking water. USEPA

proposed to set the MCLG for

Cryptosporidium at zero based on

animal studies and human

epidemiology studies of waterborne

outbreaks of cryptosporidiosis. The

proposal also focused on treatment

requirements for the waterborne

pathogens Giardia lamblia,

Cryptosporidium, Legionella and

viruses that would apply to all public

water systems that use surface water or

ground water under the influence of

surface water and serve 10,000 people

or more. Major features of the proposal

included a stricter watershed control

requirement for systems using surface

water that wish to avoid filtration; a

change in the definition of ground water

under the influence of surface water to

include the presence of

Cryptosporidium; a periodic sanitary

survey requirement for all systems using

surface water or ground water under the

influence of surface water; and several

alternative requirements, described

below, for augmenting treatment control

of Giardia lamblia, Cryptosporidium,

and viruses. USEPA also requested

comment on several supplemental

provisions and on other related issues,

described below.

2. Alternative Treatment Requirements

USEPA proposed five treatment

alternatives for controlling Giardia

lamblia, Cryptosporidium, and viruses.

Each alternative included several

options. Alternative A addressed

enhanced treatment for Giardia lamblia

only. Alternatives B and C addressed

treatment for Cryptosporidium only.

Alternative D addressed enhanced

treatment for viruses only. Alternative E

would maintain existing levels of

treatment for Giardia lamblia and

viruses.

a. Alternative A. Enhanced treatment

for Giardia lamblia. The SWTR

currently requires a 99.9 percent (3-log)

removal/inactivation of Giardia lamblia

for all surface waters, regardless of

Giardia lamblia cyst concentrations in

the source water. Under Alternative A,

the minimum level of treatment a

system would be required to provide

(e.g., 3, 4, 5 or 6 log removal/

inactivation) would depend on the

Giardia lamblia density in the source

water as determined by monitoring over

some specified interval of time. The

level of prescribed treatment for a

particular system would correspond to

providing water below an annual risk

level for Giardia lamblia infections (e.g.

10¥4).

b. Alternative B. Specific Treatment

for Cryptosporidium. USEPA also

proposed a treatment technique for

Cryptosporidium similar to the proposal

for Giardia under Alternative A, such

that the required level of

Cryptosporidium treatment for any

particular system would depend on the

density of Cryptosporidium in the

source water.

c. Alternative C. 99% (2-log) removal

of Cryptosporidium. Under this

alternative, USEPA would require

systems to achieve at least a 99% (2-log)

removal of Cryptosporidium by

filtration (with pretreatment). The 2-log

level was based on the premise that a 3-

log level (as currently required for

Giardia removal/inactivation) is not

economically or technologically

possible, since data suggests that

Cryptosporidium is consistently more

resistant to disinfection than is Giardia.

USEPA indicated that it would continue

to assess new field and laboratory data

to control Cryptosporidium by physical

removal and disinfection for

consideration in subsequent microbial

regulations.

d. Alternative D. Specific disinfection

treatment for viruses. The SWTR

required systems to achieve a four-log

removal/inactivation of viruses. This is

to be achieved through a combination of

filtration and disinfection or, for

systems not required to filter their

source waters, by disinfection alone.

However, this level of treatment may

not be adequate to achieve a particular

health risk (e.g., 10¥4 infections/yr/

person) for viruses. Viruses are of

particular concern, given that one or

several virus particles may be infectious

(Regli et al.,1991) and that several

enteric viruses are associated with

relatively high mortality rates (Bennett

et al., 1987). Failure or impairment of

filtration performance could allow

substantial pathogen contamination of

drinking water, particularly if the

disinfection barrier following filtration

is minimal.

Alternative D would require that

systems provide sufficient disinfection

such that disinfection alone would

achieve at least a 0.5-log inactivation of

Giardia lamblia or, alternatively, a 4-log

inactivation of viruses. This proposed

approach would be independent of the

level of physical removal or the source

water density of viruses. If the filtration

process was able to remove three logs of

Giardia lamblia, a system would still

have to provide at least an additional

0.5-log inactivation of Giardia lamblia

or 4-log inactivation of viruses by

disinfection.

e. Alternative E. No change to existing

SWTR treatment requirements for

Giardia lamblia and viruses. Alternative

E maintains existing SWTR levels of
59492 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

treatment for Giardia lamblia and

viruses. USEPA could regulate

Cryptosporidium directly (e.g.,

Alternative C above) or make a finding

that existing SWTR filtration and

disinfection requirements are adequate

to control this organism.

3. Possible Supplemental Treatment

Requirements

USEPA also requested comment on

three supplemental requirements

regarding uncovered finished water

reservoirs, cross connection control and

State notification of turbidity levels.

a. Uncovered Finished Water

Reservoirs. As part of the 1994 proposal,

USEPA requested comment on possible

supplemental requirements for

uncovered finished water reservoirs.

The Agency noted that USEPA

guidelines recommend that all finished

water reservoirs be covered (USEPA,

1991a) and that the American Water

Works Association (AWWA) also has

issued a policy statement that strongly

supports the covering of such reservoirs

(AWWA, 1993).

b. Cross Connection Control Program.

USEPA requested comment on whether

to require States or public water systems

to have cross connection control

programs. Plumbing cross-connections

are actual or potential connections

between a potable and non-potable

water supply (USEPA, 1989a).

According to Craun (1991), 24% of the

waterborne disease outbreaks that

occurred during 1981–1990 were caused

by water contamination in the

distribution system, primarily as the

result of cross-connections and main

repairs.

c. State Notification of High Turbidity

Levels. USEPA also requested comment

on whether to require systems to notify

the State as soon as possible for

persistent turbidity levels above the

performance standards or for any other

situation that is not now a violation of

the turbidity standards. Under the

SWTR, any time the turbidity of a

treatment plant’s combined filter

effluent exceeds 5 NTU the system must

notify the State as soon as possible, but

no later than the end of the next

business day. In addition, the system

must notify the public as soon as

possible, but in no case later than 14

days after the violation.

USEPA indicated in the proposal that

it was considering broadening the

requirement for State notification. The

Agency suggested it might, for example,

require systems to notify the State as

soon as possible if at any point during

the month it becomes apparent that a

system will violate the monthly 95th

percentile turbidity performance

standard specified in the SWTR, rather

than wait to the end of the month.

USEPA outlined a number of public

health reasons for requiring swift State

notification for persistent turbidity

levels. Pathogens may accompany the

turbidity particles that exit the filters,

especially with poor quality source

waters. High turbidity levels in the

filtered water, even for a limited time,

may represent a significant risk to the

public. USEPA’s proposed approach

was intended to allow States to respond

in controlling a potentially serious

problem more quickly.

4. Other related issues. The Agency

also requested comments on other

issues related to possible IESWTR

options. A number of these are listed

below.

(a) To what extent should the ESWTR

address the issue of recycling filter

backwash, given its potential for

increasing the densities of Giardia

lamblia and Cryptosporidium on the

filter?

(b) Should the ESWTR define

minimum certification criteria for

surface water treatment plant operators?

Currently the SWTR (40 CFR 141.70)

requires such systems to be operated by

‘‘qualified personnel who meet the

requirements specified by the State.’’

(c) What criteria, if any, should the

ESWTR include to ensure that systems

optimize treatment plant performance?

(d) Should turbidity performance

criteria be modified? Should criteria

pertain to individual filters?

(e) Should the rule include a

performance standard for particle

removal?

(f) Should the rule include a

requirement for an early warning for

high turbidity?

(g) Under what conditions could

systems be allowed different log

removal credits than is currently

recommended in the SWTR Guidance

Manual?

(h) How should USEPA decide, in

developing a Notice of Data Availability,

what treatment approach(es) is most

suitable for additional public comment?

II. New Information and Key Issues to

be Addressed

A. MCLG for Cryptosporidium

1. Summary of 1994 Proposal and

Public Comments

The July 29, 1994, Federal Register

notice proposed to set the MCLG for

Cryptosporidium at zero. The purpose

of the MCLG is to protect public health.

The reasons for this determination were

based upon animal studies and human

epidemiology studies of waterborne

outbreaks of cryptosporidiosis.

Most commenters supported an

MCLG of zero for Cryptosporidium.

Those who provided reasons stated that

(1) a single cell could infect, and data

do not support a threshold dose below

which an outbreak or disease will not

occur, (2) the organism is present in

water and has caused major waterborne

disease outbreaks, and (3) it is

consistent with the goals set under the

SWTR and Total Coliform Rule.

Commenters who opposed the proposed

MCLG stated that USEPA needed more

health risk and organism/disease

transmission data and better analytical

methods before setting an MCLG and

regulating Cryptosporidium.

2. New data and Perspectives

Since publication of the proposed

rule, results of a human feeding study

have become available. Dupont et al.

(1995) fed 29 healthy volunteers single

doses ranging from 30 to 1 million C.

parvum oocysts obtained from a calf. Of

the 16 volunteers who received 300 or

more oocysts, 88% became infected. Of

the five volunteers who received the

lowest dose (30 oocysts), one became

infected. The median infective dose was

132 oocysts. According to a

mathematical model based upon the

Dupont et al. data, 0.5% of a population

exposed to an average dose of one

oocyst, would be expected to become

infected. (Haas et al., 1996).

An important concern is that certain

populations are at greater risk of

waterborne disease infection than

others. These vulnerable populations

include the immunocompromised;

children, especially the very young; the

elderly; and pregnant women (Gerba et

al. 1996; Fayer and Ungar 1986). The

most significant segment within these

vulnerable populations with regard to

cryptosporidiosis is people who are

immunocompromised. In patients with

severely weakened immune systems,

(e.g cancer, AIDS patients),

cryptosporidiosis can be serious, longlasting and sometimes fatal. There is

concern about cryptosporidiosis in

immunocompromised individuals

because currently there is no cure for

the disease.

C. parvum is the only

Cryptosporidium species known for

certain to infect humans. One

controversial report (the only one of its

kind) found evidence that C. baileyi,

which infects birds, was present in the

stools and other autopsied organs of an

immunodeficient patient (Ditrich et al.,

1991). There was no indication that

Cryptosporidium had been responsible

in this instance for any adverse health

effects. C. parvum also infects many

other mammals. While C. parvum is a
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59493

well-documented human pathogen,

strain variation may occur and one

strain may cause infection and/or

disease at a higher or lower

concentration than other strains. USEPA

is currently funding research

[Cryptosporidium virulence study using

different strains, Herbert Dupont] to

examine this issue.

There is some question about the

taxonomy (i.e., classification) of species

within the genus Cryptosporidium. Up

until 1980, classification was based on

the assumption that a particular species

only infected one type of animal. This

assumption appears to be incorrect;

hence other appropriate taxonomy

schemes have been suggested.

An important issue not directly

related to the MCLG involves the

measurement of C. parvum in water.

With current technology, it is often very

difficult to distinguish between viable

and non-viable oocysts. When

Cryptosporidium is identified it is often

not clear whether it is C. parvum or

another species. Several

Cryptosporidium species look similar to

C. parvum and react to ‘‘specific’’ C.

parvum stains in a like manner (crossreactions). In addition, it can be difficult

to distinguish Cryptosporidium from

alga and invertebrate eggs (Clancy et al.

1994)

3. Advisory Committee

Recommendations and Related Issues

The M-DBP Federal Advisory

Committee supported the proposed

establishment of a Cryptosporidium

MCLG at zero. However, a key issue

identified by the Committee and public

commenters is whether the MCLG

should be set at the genus level (i.e.,

Cryptosporidium), as proposed, or at the

more specific species level (i.e., C.

parvum). Setting the MCLG at the genus

level would automatically include any

Cryptosporidium species other than C.

parvum that is later found to be

pathogenic to humans. In contrast,

setting an MCLG at the species level

would indicate that only C. parvum

infects humans, and would also be

consistent with the approach taken

under the SWTR for Giardia where the

MCLG is set at the species level (i.e., G.

lamblia). USEPA has not decided which

approach is most appropriate and seeks

public comment on this issue.

As indicated above, USEPA’s intent in

establishing this MCLG at zero is to

protect public health. The Agency

believes there is adequate research data

to support this determination. However,

as noted above, the Agency recognizes

that there is scientific uncertainty on the

issue of Cryptosporidium taxonomy and

on the question of cross reactions

between species. USEPA expects further

clarification on this issue as research

continues, Cryptosporidium analytical

methods improve, and more is learned

about the circumstances under which

cross-reactivity between species occurs.

The Agency also wishes to emphasize

that the scope or specificity of the

MCLG may be modified in the future to

reflect new research and additional

information about particular species

that represent a significant risk to

human health.

As part of this notice, USEPA requests

comment on whether to establish a

Cryptosporidium MCLG at the genus

level as proposed or at the species level

(i.e., Cryptosporidium vs.

Cryptosporidium parvum). USEPA also

requests copies of any additional

research, data or other information

related to this issue.

B. Removal of Cryptosporidium by

Filtration

1. Summary of 1994 Proposal and

Public Comments Received

One of USEPA’s proposed treatment

Alternatives (Alternative C) would

require filtered systems to achieve at

least a 2 log removal of Cryptosporidium

oocysts. USEPA recognized that the

proposed removal level was based on

limited data and therefore solicited

comment on whether other minimum

removal levels might be appropriate.

Most commenters addressing the

issue of treatment alternatives

supported Alternative C. Some

commenters opposed any treatment

requirement greater than a 2 log removal

due to a lack of better understanding of

dose-response, effectiveness of

treatment, and analyses to justify the

higher treatment costs involved.

Other commenters referred to specific

studies (Nieminski 1995; Patania et al.,

1995) that provided additional

information on Cryptosporidium

removal. One commenter cited a study

(Parker and Smith, 1993), where oocyst

damage was observed after agitation

with sand. This study postulated that

oocysts may be damaged as they pass

through the filtration media. This

commenter also pointed to the lack of

data on cyst removal by full-scale plants

and recommended that additional

research be conducted. Some

commenters recognized the need to

regulate Cryptosporidium, but opposed

having the level of treatment based

upon source water pathogen density

(alternative B). One commenter

indicated that further implementation

and evaluation of the adequacy of the

SWTR needs to occur before modifying

it.

2. New Data and Perspectives

a. Rapid Granular Filtration. Table 1

summarizes research pertinent to

Cryptosporidium and Giardia lamblia

removal efficiencies by rapid granular

filtration. Brief descriptions of these

studies and a summary of key points

follow.

TABLE 1.—CRYPTOSPORIDIUM AND GIARDIA LAMBLIA REMOVAL EFFICIENCIES BY RAPID GRANULAR FILTRATION

Type of treatment plant Log removal Experimental design Researcher

Conventional filtration plants .............. Crypt 2.7–5.9 ..................................... Pilot Plants ......................................... Patania et al. 95.

Do ................................................ Giardia 3.4–5.8 .................................. ......do ................................................. Do.

Do ................................................ Crypt 2.3–3.0 ..................................... Pilot scale plant ................................. Nieminski/Ongerth 95.

Do ................................................ Giardia 3.3–3.4 .................................. +full scale plant with seeded cysts/

oocysts.

Do.

Do ................................................ Crypt 2.7–3.1 ..................................... Pilot Plants ......................................... Ongerth/Pecaroro 95.

Do ................................................ Giardia 3.1–3.5 .................................. ......do ................................................. Do.

Do ................................................ Crypt 2–2.5 ........................................ Full scale plants ................................. LeChevallier et al. 91b.

Do ................................................ Giardia 2–2.5 ..................................... Full scale plants ................................. LeChevallier et al. 91b.

Do ................................................ Crypt 2.3–2.5 ..................................... Full scale plants ................................. LeChevallier/Norton 92.

Do ................................................ Giardia 2.2–2.8 .................................. ......do ................................................. Do.

Do ................................................ Crypt 2–3 ........................................... Pilot scale plant ................................. Foundation for Water.

Research 94.

Do ................................................ Giardia and ........................................ Full scale plant ................................... Kelley et al. 95.

DoCrypt 1.5–2 ............................. operation considered ot optimized).

Direct filtration plants .......................... Crypt 1.5–4.0 ..................................... Pilot Plants ......................................... Patania et al. 1995.

Do ................................................ Giardia 1.5–4.8 .................................. ......do ................................................. Do.
59494 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

TABLE 1.—CRYPTOSPORIDIUM AND GIARDIA LAMBLIA REMOVAL EFFICIENCIES BY RAPID GRANULAR FILTRATION—

Continued

Type of treatment plant Log removal Experimental design Researcher

Do ................................................ Crypt 2.8–3.0 ..................................... ......do ................................................. Nieminski/Ongerth 95.

Do ................................................ Giardia 3.3–3.9 .................................. ......do ................................................. Do.

Do ................................................ Crypt 2–3 ........................................... ......do ................................................. West et al. 1994.

Patania, Nancy L; et al. 1995

Raw water turbidities were between

0.2 and 13. When treatment conditions

were optimized for turbidity and

particle removal at four different sites,

Cryptosporidium removal ranged from

2.7 to 5.9 log and 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, by up to l log

greater than when filter effluent

turbidities were greater than 0.1 NTU

(within the 0.1 to 0.3 NTU range) (see

Figures 1 and 2 below).

Cryptosporidium removal rates of less

than 2.0 log (indicated in Figures 1 and

2) occurred at the end of the filtration

cycle.

Blackened data points in these figures

represent data in which oocysts were

not detected in the filtered water. The

log removal values shown would be

greater than indicated had the influent

oocyst concentration been sufficiently

high to show oocyst detection in the

filtered water. The researchers also

noted that removal of Cryptosporidium

was 0.4 to 0.9 log lower during filter

ripening than during stable filter

operation; Giardia removal was

generally 0.4 to 0.5 log lower during

ripening. Cryptosporidium removal was

1.4 to 1.8 log higher for conventional

treatment (including sedimentation) as

compared to direct filtration. Similarly,

Giardia removal was 0.2 to 1.8 log

higher. Figures 1 and 2 below show the

log removal rates discussed above.

BILLING CODE 6560–50–P
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59495
59496 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

BILLING CODE 6560–50–C

Nieminski, Eva C. and Ongerth, Jerry E.

1995

This study evaluated performance in

a pilot plant and in a full scale plant

(not in operation during the time of the

study) and considered two treatment

modes: direct filtration and

conventional treatment. The source

water of the full scale plant had

turbidities typically between 2.5 and 11

NTU with a peak level of 28 NTU. The

source water of the pilot plant typically

had turbidities of 4 NTU with a

maximum of 23 NTU. For the pilot

plant, achieving filtered water

turbidities between 0.1–0.2 NTU,

Cryptosporidium removals averaged 3.0

log for conventional treatment and 3.0

log for direct filtration, while the

respective Giardia removals averaged

3.4 log and 3.3 log. For the full scale

plant, achieving similar filtered water

turbidities, 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 different

source water quality during the filter

runs.

Ongerth, Jerry E. and Pecoraro, J.P. 1995

This project used very low turbidity

source waters (0.35 to 0.58 NTU). With

optimal coagulation, 3 log removal for

both cysts were obtained. In one test

run, where coagulation was

intentionally suboptimal, the removals

were only 1.5 log for Cryptosporidium

and 1.3 log for Giardia. This

emphasized the importance of proper

coagulation for cyst removal even

though the effluent turbidity was less

than 0.5 NTU.

LeChevallier, Mark W. and Norton,

William D. 1992

Source water turbidities ranged from

less than 1 to 120 NTU. Removals of

Giardia and Cryptosporidium (2.2–2.8

log) were slightly less than those

reported by other researchers, possibly

because full scale plants were studied,

under less ideal conditions than the

pilot plants. The participating treatment

plants were in varying stages of

treatment optimization. Removal

achieved a median of 2.5 log for

Cryptosporidium and Giardia.

LeChevallier, Mark W.; Norton, William

D.; and Lee, Raymond G. 1991b

This study evaluated removal

efficiencies for Giardia and

Cryptosporidium in 66 surface water

treatment plants in 14 States and 1

Canadian province. Most of the utilities

achieved between 2 and 2.5 log

removals for both Giardia and

Cryptosporidium. When no cysts were

detected on the finished water below

detection protozoan levels were set at

the detection limit for calculating

removal efficiencies.

Foundation for Water Research 1994

Raw water turbidity ranged from 1 to

30 NTU. Cryptosporidium oocyst

removal was between 2 and 3 log.

Investigators concluded that any

measure which reduced filter effluent
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59497

turbidity should reduce risk from

Cryptosporidium. The importance in

selecting coagulants, dosages, and pH

should not be overlooked. Apart from

turbidity, indicators of possible reduced

efficiency for oocyst removal would be

increased color and dissolved metal ion

coagulant concentration in the effluent,

for these are indications of reduced

efficiency of coagulation/ flocculation.

Kelley, M.B. et al. 1995

Protozoa removal was between 1.5

and 2 log. The authors speculated that

this low Cryptosporidium removal

occurred because the coagulation

process was not optimized, though the

finished water turbidity was less than

0.5 NTU. Also, when cysts were not

detected in the finished water below

detection values were assumed as

filtered water concentration levels.

West, Thomas; et al. 1994

Pilot scale direct filtration was used

with anthracite mono-media at filtration

rates of 6 and 14 gpm/sq ft. Raw water

turbidity was 0.3 to 0.7 NTU. Removal

efficiencies for Cryptosporidium at both

filtration rates were 2 log during filter

ripening (despite turbidity exceeding

0.2 NTU), and 2 to 3 log for the stable

filter run, declining significantly during

particle breakthrough. When effluent

turbidity was less than 0.1 NTU,

removal typically exceeded 2 log. Log

removal of Cryptosporidium generally

exceeded that for particle removal.

Summary of Studies

The studies described above indicate

that rapid granular filtration, when

operated under appropriate coagulation

conditions and optimized to achieve a

filtered water turbidity level of less than

0.3 NTU, should achieve at least 2 log

of Cryptosporidium removal. Removal

rates vary widely, up to almost 6 log,

depending upon water matrix

conditions, filtered water turbidity

effluent levels, and where and when

removal efficiencies are measured

within the filtration cycle. The highest

log pathogen removal rates occurred in

those pilot plants and systems which

achieved very low finished water

turbidities (less than 0.1 NTU).

Members of the M–DBP Advisory

Committee discussed that tighter

turbidity performance criteria would

increase the likelihood of systems

achieving higher oocyst removal rates.

As a general principle, members of the

M–DBP Advisory Committee indicated

that if a utility were required to achieve

less than 0.3 NTU 95% of the time, it

would target substantially lower

turbidity levels in order to have

confidence that it will not exceed the

0.3 level. This principle was also

recognized by the M–DBP Advisory

Committee’s Technical Work Group and

served as a technical basis for much of

the Committee’s discussion of turbidity

(i.e., that if the performance standard is

0.3 NTU systems would target achieving

less than 0.2 NTU 95 percent of the

time).

The Patania and Nieminski/Ongerth

studies as they relate to finished water

turbidity levels and log removal are

particularly relevant to this point. These

particular studies involve finished water

turbidity at low levels in the same range

as the finished water target identified by

the Committee. The associated removal

of Cryptosporidium at these turbidity

levels was reliably in the range of 2 log

or greater.

Other key points discussed during the

Advisory Committee’s deliberations

related to the studies include:

• As turbidity performance improves

for treatment of a particular water, there

tends to be greater removal of

Cryptosporidium.

• Pilot plant study data in particular

indicate high likelihood of achieving at

least 2 log removal when plant

operation is optimized to achieve low

turbidity levels. Moreover, pilot studies

represented in the table tend to be for

low-turbidity waters, which are

considered to be the most difficult to

treat regarding particulate removal and

associated protozoan removal. Since

high removal rates have been

demonstrated in pilot studies using

lower-turbidity source waters, it is

likely that similar or higher removal

rates would be achieved for higherturbidity source waters.

• The evaluation of Cryptosporidium

removal in full-scale plants can be

difficult in that this data includes many

non-detects in the finished water. In

these cases, values assigned at the

detection limit will likely result in overestimation of oocysts in the finished

water. This in turn means that removal

levels will tend to be under-estimated.

• Another factor that contributes to

differences among the data is that some

of the full-scale plant data comes from

plants that are not optimized, but that

still meet existing SWTR requirements.

In such cases, oocyst removal may be

less than 2 log. In those studies that

indicate that full-scale plants are

achieving greater than 2 log removal

(LeChevallier studies in particular), 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;

—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, which is the

predominant period).

b. Other Filtration Technologies.

Other filtration technologies include

slow sand and diatomaceous earth

filtration. ‘‘Technologies and Costs for

the Treatment of Microbial

Contaminants in Potable Water

Supplies, October 1988’’ by USEPA

(1988) listed research studies indicating

that a well designed and operated plant

using these technologies is capable of 3-

to 4-log removal of Giardia and viruses.

Recent findings appear in Table 2

below.

TABLE 2.—CRYPTOSPORIDIUM AND GIARDIA LAMBLIA REMOVAL EFFICIENCIES

Type of treatment plant Log removal Experimental design Researcher

Slow Sand .......................................... Giardia >3 .......................................... Pilot plant at 4.5 to ............................ Schuller and Ghosh, 91.

Crypt >3 ............................................. 16.5 degrees C. .................................

Crypt 4.5 ............................................ Full scale plant ................................... Timms et al., 1995

Diatomaceous Earth ........................... Giardia >3 .......................................... Pilot plant, addition of ........................ Schuler and Ghosh, 90.

Crypt >3 ............................................. coagulant increased.

....................................................... removal beyond.

....................................................... values shown.
59498 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

c. Multiple Barrier Approach.

The M–DBP Advisory Committee

engaged in extensive discussion

regarding the adequacy of relying solely

on physical removal to control

Cryptosporidium in drinking water

supplies and on the need for

inactivation. There was a substantial

absence of technical consensus on how

to or whether it is currently possible to

adequately measure Cryptosporidium

inactivation efficiencies for various

disinfection technologies. This issue

emerged as a significant impediment to

addressing inactivation in the IESWTR.

As part of the original 1994 proposal,

USEPA included control strategies that

would entail the development of a map

of inactivation efficiencies for

Cryptosporidium. As discussed later in

Section M. of this Notice, adequate

information to develop such a map is

not available at this time. The Advisory

Committee discussion recognized,

however, that inactivation requirements

may be appropriate and necessary under

future regulatory scenarios and that

physical removal by filtration may not

be sufficient under all circumstances or

for all source waters.

As part of the development process

for the long term ESWTR, the Advisory

Committee recommended that USEPA

request comment on a risk-based

proposal for Cryptosporidium

embodying the multiple barrier

approach (e.g., source water protection,

physical removal, inactivation, etc.),

including, where risks suggest

appropriate, inactivation requirements.

In establishing the LTESWTR, the

Committee recommended that the

following issues be evaluated:

—Data and research needs and

limitations (e.g., occurrence,

treatment, viability, active disease

surveillance, etc.);

—Technology and methods capabilities

and limitations;

—Removal and inactivation

effectiveness;

—Risk tradeoffs including risks of

significant shifts in disinfection

practices;

—Cost considerations consistent with

the SDWA;

—Reliability and redundancy of

systems; and

—Consistency with the requirements of

the Act.

3. Advisory Committee

Recommendations and Related Issues

USEPA reiterates its request for

comment on the following

recommendations of the M–DBP

Advisory Committee.

All surface water systems that serve more

than 10,000 people and are required to filter

must achieve at least a 2-log removal of

Cryptosporidium. Systems which use rapid

granular filtration (direct filtration or

conventional filtration treatment-as currently

defined in the SWTR), and meet the turbidity

requirements described in section II.C. are

assumed to achieve at least a 2-log removal

of Cryptosporidium. Systems which use slow

sand filtration and diatomaceous earth

filtration and meet existing turbidity

performance requirements under the SWTR

(less than 1 NTU for the 95th percentile or

alternative criteria as approved by the State)

are assumed to achieve at least 2-logs

removal of Cryptosporidium.

Systems may demonstrate that they

achieve higher levels of physical removal.

C. Turbidity Control

1. Summary of 1994 Proposal as it

Relates to Turbidity Issues and Public

Comments

Finished water turbidity levels are

currently regulated by USEPA under the

SWTR as a treatment technique to

ensure removal of Giardia and viruses.

The SWTR requires systems to monitor

the turbidity of the combined filter

effluent every four hours at each

treatment plant. Systems using direct

filtration or conventional treatment

must achieve a combined filter effluent

turbidity level of no more than 0.5 NTU

in 95% of the measurements in each

month and never exceed 5 NTU. Failure

of individual filters may allow

pathogens to enter the distribution

system. However, the SWTR does not

presently require systems to monitor the

effluent of individual filters.

As a treatment technique, turbidity is

an indicator of filtration performance.

Treatment plants are, as noted above,

required to meet certain turbidity levels

to meet the removal requirements for

Giardia. Although turbidity is not a

direct indicator of health risk, a very

low turbidity level of the treated water

is in general a good indicator of effective

Cryptosporidium and Giardia oocyst

and cyst removal by rapid granular

filtration. USEPA continues to believe

that turbidity is the most readily

measurable parameter to indicate

filtration treatment effectiveness.

A primary focus of the 1994 proposal

was the establishment of treatment

requirements that would address public

health risks from high densities of

pathogens in poor quality source waters

and from the waterborne pathogen

Cryptosporidium. As discussed earlier

in this Notice, waterborne pathogens

have caused significant disease

outbreaks in the United States.

Approaches outlined in the 1994

proposal included treatment

requirements based on site-specific

concentrations of pathogens in source

water and a proposed 2-log removal

requirement for Cryptosporidium by

filtration.

USEPA also specifically requested

comment on what criteria, if any,

should be included to ensure that

systems optimize treatment plant

performance and on whether any of the

existing turbidity performance criteria

should be modified (e.g., should

systems be required to base compliance

with the turbidity standards on

individual filter effluent monitoring in

lieu of or in addition to monitoring the

confluence of all filters; and should any

performance standard value be

changed). In addition, the Agency

requested comment in the 1994

proposal on possible supplemental

requirements for State notification of

persistent high turbidity levels (e.g.,

broadening the requirements for State

notification of turbidity exceedances).

Some comments suggested and

supported a revised approach to the

IESWTR that would focus on optimizing

existing water treatment processes to

provide insurance against microbial

disease outbreak in the absence of

source water occurrence data. Another

comment suggested that current levels

of treatment, including filtration, have a

sufficient degree of effectiveness in

preventing transmission of

Cryptosporidium in drinking water.

One commenter suggested that

turbidity performance standards should

not be modified until the SWTR has

been further implemented. One

commenter suggested that decreases in

turbidity standards or monitoring after

each filter should be voluntary unless

scientific data demonstrate otherwise.

Another commenter suggested that

individual filters can be evaluated

during sanitary surveys. Several

commenters supported tighter turbidity

standards and monitoring of individual

filters. Suggested turbidity performance

levels included 0.1 or less, or 0.2 NTU

as revised standards. Several

commenters supported monitoring of

individual filters, with one suggesting

backwashing of filters when turbidity

levels increase.

2. New Data and Perspectives

As presented in detail below, the MDBP Advisory Committee’s

recommendations to the Agency

included tighter turbidity performance

criteria and individual filter monitoring

requirements as part of the IESWTR.

These revised performance criteria,

along with the individual filter

monitoring requirements, would better

enable systems to demonstrate that they

meet a 2 log removal requirement for

Cryptosporidium. Because

Cryptosporidium is exceptionally
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59499

resistant to inactivation using chlorine,

physical removal by filtration is

extremely important in controlling this

organism. Data presented in the

previous section of this Notice support

modifications to the existing turbidity

requirements under the SWTR to enable

systems to demonstrate that they meet

the proposed 2 log requirement.

The revised turbidity performance

criteria would also contribute to another

of the IESWTR’s key objectives, which

is to establish a microbial backstop to

prevent significant increases in

microbial risk when systems implement

new disinfection byproduct standards

under the Stage 1 DBPR. As indicated

by data presented below, tighter

turbidity performance criteria would

reflect actual current performance for a

substantial percentage of systems

nationally. Revising the turbidity

criteria would effectively ensure that

these systems continue to perform at

these levels (in addition to resulting in

improved performance by systems that

currently meet the existing criteria but

that operate at levels higher than those

suggested in the Advisory Committee’s

recommendations). The other major

component of a microbial backstop

would be provisions for disinfection

profiling and benchmarking, which are

discussed in Section D. of this Notice.

The revisions to the turbidity

provisions (including the individual

filter provisions) recommended by the

Committee would also contribute to the

microbial backstop objective in direct

relationship to the treatment process

itself. The reliability of the disinfection

barrier as a means for preventing

waterborne disease should increase

substantially as a result of these tighter

turbidity provisions because:

—There would be fewer and shorter

periods of elevated turbidity during

which the disinfection barrier could

be compromised; and

—The removal of particulate matter

achieved by the filtration process will

both be higher on average and more

consistent throughout the treatment

cycle, thus putting less burden on the

disinfection barrier.

a. 95th Percentile and Maximum

Turbidity Levels of Composite Filtered

Water.

Three data sets, summarizing the

historical turbidity performance of

various filtration plants, were evaluated

to assess the national impact of

modifying existing turbidity

requirements. This included turbidity

information from the American Water

Works Service Company (AWWSC,

1997), a multi-State data set (which was

analyzed in two sets) (SAIC, 1997), and

information from plants participating in

the Partnership for Safe Water program

(Bissonette, 1997). Only turbidity data

from plants serving populations greater

than 10,000 persons were used. The

analyses also included only plants that

met the current 95th percentile turbidity

standard, 0.5 NTU, and the current

maximum turbidity standard, 5 NTU, in

all months. Each of the data sets was

analyzed to assess the current

performance of plants with respect to

the number of months in which selected

95th percentile and maximum turbidity

levels were exceeded.

The AWWSC is a privately-held

company that owns and operates for

profit about 70 water treatment facilities

located across the country. For this

analysis, the AWWSC data set

(AWWSC, 1997) included one year’s

data for 45 plants in 10 States. The

States, with number of plants in each

state listed in parentheses, are as

follows: California (1), Connecticut (3),

Iowa (2), Indiana (6), Maryland (1),

Missouri (2), Pennsylvania (24),

Tennessee (1), Virginia (2), and West

Virginia (3). USEPA analyzed the

composite filtered effluent turbidity

data obtained from the AWWSC plants

measured every 4-hours.

The analyses examined two variations

of turbidity data obtained from the

multi-State data set (SAIC, 1997). The

multi-State data set included 86 plants

in 11 states. The States, with number of

plants in each state listed in

parentheses, are as follows: California

(10), Georgia (5), Kansas (9), New Jersey

(5), Ohio (12), Oregon (10), Rhode Island

(6), Texas (9), Wisconsin (8), West

Virginia (6), Wyoming (6). The State

data was analyzed as two data sets,

denoted as State 1 and State 2. The State

1 data set included only plant

information with measurements every 4

hours, comprising slightly more than

half of the State data (47 plants in CA

(10), OR (10), TX (9), WI (6), WY (6),

WV (6)). The State 2 data set was

comprised of both the State 1 data and

other data including plant information

consisting of daily maximum turbidity

values only, altogether 86 plants.

The State 1 data set was expected to

provide a more accurate picture of

typical plant performance among the

plants in the entire State data set

because there were more data points per

plant. However, the State 2 data set

increased regional coverage by

incorporating data from five additional

States (GA, KS, NJ, OH, RI) to reflect

additional geographic variation that may

not have been captured in the State 1

data set.

In order to determine how many of

the systems met lower 95th percentile

turbidity levels based on turbidity

measurements every four hours, the data

from those States in which systems only

report maximum daily values had to be

statistically adjusted. The adjustment is

necessary to take into account the

difference in the number of reported

measurements in a month that can

exceed a particular level (e.g., 0.3 NTU)

without exceeding the monthly 95th

percentile for that level. (Systems that

report measurements every four hours

can have up to 9 of 180 measurements

(5%) that exceed the level in a month;

however, there is no way to directly

calculate an equivalent value for

systems that only report daily maximum

values without making some

adjustment.) No adjustment was

necessary for assessing monthly

maximum turbidity levels.

The State 2 analyses adjusted the

monthly 95th percentile turbidity levels

for plants with only daily maximum

data. This was done because the 95th

percentile based on 31 daily turbidity

maximums a month will overestimate

the 95th percentile based on 186 daily

measures (or measurements every 4

hours). To assess the magnitude of the

bias, the State 1 data were used to

examine the relationship between the

95th percentile of the daily maximums

and the 95th percentile of the daily

measurements.

The State 2 monthly 95th percentile

analyses were obtained by dividing the

estimated monthly 95th percentiles of

those systems reporting only daily

maximums by a factor of 1.2 to account

for bias. This factor was derived as

follows. The daily maximum was

determined for each day in the State 1

data set and a monthly 95th percentile

(of the 30 or 31 daily maximums) was

determined, i.e., the second largest daily

maximum. The corresponding monthly

95th percentile based on the daily data

was also determined. The ratio of these

two values was then calculated and

summarized across months. The median

ratio across all months was 1.2, with 90

percent of the ratios ranging between 1.0

and 1.9. The analysis used to derive the

adjustment factor examined only plants

that reported six values per day.

The remaining data set included in

the turbidity analysis was of plants

participating in the Partnership for Safe

Water. The Partnership for Safe Water is

a joint venture of several organizations,

including the American Water Works

Association, the Association of State

Drinking Water Administrators, the

Association of Metropolitan Water

Agencies, the National Association of

Water Companies, the American Water

Works Association Research Foundation

and USEPA. These organizations
59500 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

entered into a voluntary ‘‘partnership’’

with the nation’s drinking water

filtration plants treating surface water to

tighten treatment practices and

operational controls to reduce the risk

from Cryptosporidium and other

waterborne pathogens. The Partnership

approach, described in the ‘‘Partnership

for Safe Water Voluntary Water

Treatment Plant Performance

Improvement Program Self-Assessment

Procedures’’ (USEPA et al. 1995), is

based on USEPA’s Composite

Correction Program (CCP). The CCP is a

voluntary program which is described

in detail in the handbook Optimizing

Water Treatment Plant Performance

Using the Composite Correction

Program—USEPA/625/6–91/027. The

Partnership for Safe Water utility

membership consists of 199 utilities

representing almost 280 water treatment

plants. These plants serve

approximately 80 million persons. The

Partnership consists of four phases with

each phase providing tools and

methodologies to assist utilities in

progressing toward a higher quality

finished water. The following data

summarizes turbidity performance

based on 4-hour measurements reported

by the Partnership utilities for 12

months overlapping 1995 and 1996. The

data represents a composite of

Partnership utilities that have

completed varying phases of

Partnership activities, ranging from

having just joined to having progressed

well into the self-assessment phase

(phase 3). All data were derived from

the 1997 Partnership for Safe Water

Annual report (Bissonette, 1997).

The results of the analyses of all of the

data sets are shown in Tables 3 and 4.

Tables 3 and 4 indicate the extent to

which plants, as currently operated, are

meeting different turbidity levels.

Conversely the data indicate the portion

of utilities which might need to alter

existing practice in order to meet lower

turbidity limits, if such limits were

required through regulation.

Table 3 is organized to reflect the

extent to which utilities are currently

meeting monthly 95th percentile

turbidity limits, assuming that

compliance with such limits is

determined as currently done under the

existing monthly 95th percentile

standard of < 0.5 NTU. For example,

Table 3 indicates that 19.1 percent

(based on the Partnership data set) and

34.9 percent (based on the State 2 data

set) exceed a monthly 95th percentile

turbidity limit of 0.3 NTU at least one

month during the year for which data

were collected. Table 3 also indicates

the extent to which utilities meet a

particular limit for multiple months of

the year (i.e., for at least 3 months and

for at least 6 months). The frequency in

months by which utilities exceed a

particular monthly turbidity limit could

influence the extent of treatment that

might be needed to achieve compliance

through out the year.

The Technical Work Group (TWG)

which provided technical advice to the

Advisory Committee made the following

recommendations for estimating

national compliance forecasts.

(1) The State 2 data set could be used

as a reference point for estimating

potential compliance burdens for

systems serving less than 100,000

people. The Partnership data could be

used as a reference point for estimating

potential compliance burdens for

systems serving greater than 500,000

people. For systems serving between

100,000 and 500,000 people, the average

of the percentages of systems not

meeting a particular limit reflected by

the Partnership and State 2 data could

be used for estimating compliance

burdens.

(2) Estimates for systems needing to

make changes to meet a turbidity

performance limit of < 0.3 NTU should

be based on the ability of systems

currently being able to meet a 0.2 NTU

as reflected in Table 3. This assumption

would also take into account a utility’s

concern with possible turbidity

measurement error.

For example, for systems serving less

than 100,000 people, the TWG assumed

that 51.7 percent of the systems could

be expected to make treatment changes

to consistently comply with a monthly

95th percentile limit of 0.3 NTU.

Similarly, for systems serving over

500,000 people, the TWG assumed that

41.7 percent could be expected to make

treatment changes to comply with a 0.3

NTU regulatory limit.

Table 4 is organized to reflect the

extent to which utilities meet different

monthly maximum turbidity limits (i.e.,

all measurements taken during the

month must be below the indicated

limit). For example, Table 4 indicates

that 6 percent of the plants (based on

State 2 Partnership data) are currently

exceeding a monthly maximum limit of

1.0. The data in Table 4 were considered

for evaluating possible national impacts

of lowering the current maximum limit

of 5 NTU to some lower value.

Regarding maximum turbidity levels,

the Advisory Committee also discussed

filtered water turbidity levels with

respect to the cryptosporidiosis

outbreak in Milwaukee in 1993. Some

members indicated concern that filtered

water turbidities associated with the

outbreak apparently were significantly

lower than the current maximum

turbidity level of 5 NTU. Indications are

that the turbidity levels were at about 2

NTU (MacKenzie et al., 1994; Fox and

Lytle., 1996).

TABLE 3.—NUMBER AND PERCENT OF PLANTS THAT EXCEEDED MONTHLY 95TH PERCENTILE TURBIDITY LIMITS IN AT

LEAST N MONTHS OUT OF 12

Turbidity limit Data source

At least 1 month At least 3 months At least 6 months

Num Pct Num Pct Num Pct

0.1 ........................................... State 1 ................................................. 34 72.3 28 59.6 24 51.1

State 2 69 ........................................................ 80.2 59 68.6 51 59.3

AWWSC 33 ........................................................ 73.3 24 53.3 15 33.3

Partnership 177 ...................................................... 75.3 136 57.9 100 42.6

0.2 ........................................... State 1 ................................................. 17 36.2 9 19.1 2 4.3

State 2 44 ........................................................ 51.2 29 33.7 15 17.4

AWWSC 12 ........................................................ 26.7 7 15.6 2 4.4

Partnership 98 ........................................................ 41.7 51 21.7 27 11.5

0.3 ........................................... State 1 ................................................. 10 21.3 3 6.4 0 0.0

State 2 30 ........................................................ 34.9 11 12.8 3 3.5

AWWSC 6 .......................................................... 13.3 1 2.4 0 0.0

Partnership 45 ........................................................ 19.1 17 7.2 7 3.0

0.4 ........................................... State 1 ................................................. 3 6.4 0 0.0 0 0.0

State 2 9 .......................................................... 10.5 1 1.2 0 0.0

AWWSC 3 .......................................................... 6.7 0 0.0 0 0.0
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59501

TABLE 3.—NUMBER AND PERCENT OF PLANTS THAT EXCEEDED MONTHLY 95TH PERCENTILE TURBIDITY LIMITS IN AT

LEAST N MONTHS OUT OF 12—Continued

Turbidity limit Data source

At least 1 month At least 3 months At least 6 months

Num Pct Num Pct Num Pct

Partnership 22 ........................................................ 9.4 5 2.1 3 1.3

Population served ≥10,000. State 1 (4-hour daily data from 47 plants): 10 CA, 10 OR, 9 TX, 6 WI, 6 WV, 6 WY. State 2 (86 plants including

State 1 data and daily maximums * from additional plants) : 10 CA, 5 GA, 9 KS, 5 NJ, 12 OH, 10 OR, 6 RI, 9 TX, 8 WI, 6 WV, 6 WY. AWWSC:

45 plants: 1 CA, 3 CT, 2 IA, 6 IN, 1 MD, 2 MO, 24 PA, 1 TN, 2 VA, 3 WV. Partnership for Safe Water 235 plants. *For plants with only daily

maximums, the monthly 95th percentile was estimated as the 95th percentile of the daily maximums divided by 1.2. The adjustment was done to

account for the potential bias of taking the 95th percentile of daily maximums, and was based on the relationship observed in the State 1 data

between the 95th percentile of the daily maximums and the 95th percentile of the 4-hour data.

TABLE 4.—NUMBER AND PERCENT OF PLANTS THAT EXCEEDED MONTHLY MAXIMUM TURBIDITY LIMITS IN AT LEAST N

MONTHS OUT OF 12

Maximum turbidity limit Data source

At least 1 month At least 3 months At least 6 months

Num Pct Num Pct Num Pct

0.3 ........................................... State 1 ................................................. 36 76.6 15 31.9 6 12.8

State 2 69 ........................................................ 80.2 36 41.9 15 7.4

AWWSC 24 ........................................................ 53.3 10 22.2 4 8.9

Partnership 129 ...................................................... 54.9 72 30.6 37 15.7

0.5 ........................................... State 1 ................................................. 18 38.3 3 6.4 1 2.1

State 2 35 ........................................................ 40.7 7 8.1 1 1.2

AWWSC 12 ........................................................ 26.7 3 6.7 0 0.0

Partnership 65 ........................................................ 27.7 20 8.5 5 2.1

1.0 ........................................... State 1 ................................................. 1 2.1 0 0.0 0 0.0

State 2 6 .......................................................... 7.0 0 0.0 0 0.0

AWWSC 4 .......................................................... 8.9 0 0.0 0 0.0

Partnership 16 ........................................................ 6.8 4 1.7 2 0.9

2.0 ........................................... State 1 ................................................. 1 2.1 0 0.0 0 0.0

State 2 2 .......................................................... 2.3 0 0.0 0 0.0

AWWSC 0 .......................................................... 0.0 0 0.0 0 0.0

Partnership 7 .......................................................... 3.0 2 0.9 1 0.4

b. Individual Filter Performance.

During a turbidity spike, significant

amounts of particulate matter (including

oocysts, if present) may pass through

the filter. Figure 3 presents the turbidity

levels over time of a typical filter. The

greatest potential for a peak (and thus,

pathogen break-through) is near the

beginning of the filter run after filtered

backwash or start up of operation

(Amirtharajah 1988; Bucklin et al. 1988;

Cleasby 1990; and Hall and Croll 1996).

Various factors effect the duration and

amplitude of filter spikes, including

sudden changes to the flow rate through

the filter, treatment of the filter

backwash water, filter to waste

capability, and site-specific water

quality conditions. The M–DBP

Advisory Committee also discussed the

need to control turbidity spikes in order

to limit the number of oocysts passing

through the filter.

BILLING CODE 6560–50–P
59502 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

BILLING CODE 6560–50–C

c. Turbidity Measurement.

Turbidity is a measure of light scatter

that is affected by the size distribution

and shape of suspended particles in the

water. Four methods are commonly

used to measure turbidity and all are

approved for use under the SWTR. They

include the Nephelometric Method

listed in 2130B of the Standard Methods

for the Examination of Water and

Wastewater, Standard Test Method for

Turbidity of Water ASTM (1990)

D1889–94, the Nephelometric Method

in 180.1 of USEPA–600/R–93–100 and

the Great Lakes Instruments Method 2

(see section 141.74(a)(1)).

Turbidimeters which measure

turbidity commonly consist of the

following components: (1) a light source

and lenses and other optical devices to

project the light beam at the sample

container and to direct the scattered

light to the detector; (2) a transparent

cell that contains the water to be

measured; (3) light traps within the

sample chamber that minimize the

amount of stray light that reaches the

detector; and (4) a meter that indicates

the intensity of the light reaching the

detector. While turbidity measurement

has long been recognized as a means for

evaluating treatment performance for

removal of particulate matter (which

include microorganisms), issues remain

pertinent to the accuracy and precision

of the measurement (Hart et al. 1992;

Sethi et al. 1997).

Large tolerances in instrument design

criteria, intended to promote

competition among instrument

manufacturers, have lead to

turbidimeters with significantly

different design features being available

on the market. Turbidimeters with

different designs (but within the design

specifications of Standard Methods),

calibrated according to manufacturer’s

recommendations, have been shown to

provide different turbidity readings for

a given suspension (Hart et al. 1992).

The significance of this phenomenon as

it might pertain to the same water with

changing turbidities over time or

different waters in the U.S. is not

known. Therefore, narrowing

instrument design criteria could reduce

variation of turbidity measurement but

the best direction that such change

should take is not yet apparent.

Calibration procedures also affect

turbidity measurements. Calibration

typically involves placing a quantity of

a standard suspension in the

turbidimeter and then adjusting the

response so that the meter gives a

reading equal to the turbidity value

assigned to the standard. Instruments

that are calibrated with currently

approved different standard

suspensions can yield different turbidity

measurements on the same water (Hart

et al. 1992). The significance of this

phenomenon as it might pertain to the

same water with changing turbidities

over time or different waters in the U.S.

is also not known. While narrowing

specifications for current calibration

procedures could reduce variation of

turbidity measurements, the best

direction that such change should take

is not yet apparent.

Other factors that may affect turbidity

measurement include procedures used

to prepare and wipe the sample cell and

use of sample degassing procedures.

The extent to which all of the above

factors, collectively, affect turbidity

measurement is not known. However,

past performance evaluation (PE)

studies conducted by USEPA provide

some indication of accuracy and

precision of turbidity measurements

among different laboratories for a

common synthetically prepared water.

In PE studies, PE samples with known

turbidity levels are sent to participating

laboratories (who are not informed of

the turbidity level). Laboratories

participating in these studies used

turbidimeters from various

manufacturers and conducted their

analysis in accordance with calibration

and analytical procedures they are

familiar with. Thus, the variability of

the results reflect differences resulting

from using different turbidimeter

models and methods and the effects of

different laboratory procedures. Table 5

summarizes results from PE studies

conducted at turbidity levels close to

the SWTR turbidity performance limit

of 0.5 NTU. The Relative Standard

Deviation (RSD) is the Standard

Deviation divided by the mean. It

appears that the RSD at turbidity levels

considered in these PE studies are

slightly below 20%. (A RSD of 20%

implies that 95% of one-time turbidity

measurements made by different

laboratories would fall within 40% of

the mean. The RSD for an individual

laboratory, making numerous

measurements on a given sample water

would be expected to be significantly

less than that achieved among different

laboratories (using a variety of

turbidimeters as indicated in Table 5).
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59503

TABLE 5.—USEPA PERFORMANCE EVALUATION RESULTS OF TURBIDITY MEASUREMENTS (USEPA 1997d)

[Turbidity readings are expressed in NTU, and Relative Standard Deviation in %]

Study No. True Turb. No. of

samples Mean RelativeS D

34 USEPA/State ............................................................................................................. .720 54 .752 16.0

34 All Lab ....................................................................................................................... .720 1503 .744 15.8

23 USEPA/State ............................................................................................................. .650 24 .659 10.1

25 USEPA/State ............................................................................................................. .600 28 .585 13.8

25 All Lab ....................................................................................................................... .600 708 .597 16.0

25 USEPA/State ............................................................................................................. .450 29 .463 20.5

25 All Lab ....................................................................................................................... .450 707 .481 19.5

22 USEPA/State ............................................................................................................. .350 52 .406 16.1

No data is yet available on

measurement performance from PE

studies at levels less than 0.3 NTU. A

major concern expressed by participants

among the Advisory Committee is the

ability to reliably measure low turbidity

levels. The TWG assumed that if

systems operated to achieve a turbidity

limit of less than 0.2 NTU 95 percent of

the time, this would provide an

adequate margin of safety from

variability in treatment performance and

turbidity measurement error, to

consistently meet a turbidity limit of 0.3

NTU.

USEPA intends to conduct two PE

studies with true turbidities ranging

from 0.1 to 0.3 NTU. One study is

planned to begin no later than the end

of January 1998 and the other study

within 6 months thereafter. These new

studies will provide an indication of

accuracy and precision of turbidity

measurements at lower levels than

previously examined. Measurements by

on-line turbidimeters will also be

evaluated.

On-line monitoring issues: For

expedience, on-line turbidimeters are

often calibrated against a bench

instrument that has been accurately

calibrated by comparing the turbidity

level in a water sample. However, at

regular intervals they need to be taken

off line and calibrated, as for bench

instruments, by pouring the prepared

standard suspension into the chamber of

the instrument. On-line instruments

must be inspected regularly to remove

air bubbles and accumulated debris.

Fluctuations in continuous

measurements do not necessarily signify

a decrease in water treatment

performance. Fluctuations in

continuous measurements should be

investigated since they may be due to

air bubbles, debris or a temporary

disturbance due to a change in the flow

rate of sample water flow through the

turbidimeter. To address the

contingency of such phenomenon, the

Advisory Committee recommended,

based on advice from the Technical

Work Group, that turbidity spikes

should be defined on the basis of at least

2 consecutive measurements taken over

some interval of time (e.g., 15 minutes).

There is no standard design

specification for on-line turbidimeters

regarding chamber size and

recommended flow rate. Thus, turbidity

spikes of the treated water will be

reflected with a delay of a few seconds

to a few minutes, depending on

chamber volume and flow rate of the

turbidimeter. A turbidity peak measured

by a turbidimeter with a large chamber

volume and small flow rate will result

in slightly reduced peak.

3. Advisory Committee

Recommendations and Related Issues

USEPA reiterates its request for

comment on the following

recommendations of the M–DBP

Advisory Committee.

1. Turbidity Performance Requirements.

For all surface water systems that use

conventional treatment or direct filtration,

serve more than 10,000 people, and are

required to filter: (a) the turbidity level of a

system’s combined filtered water at each

plant must be less than or equal to 0.3 NTU

in at least 95 percent of the measurements

taken each month and, (b) the turbidity level

of a system’s combined filtered water at each

plant must at no time exceed 1 NTU. For

both the maximum and the 95th percentile

requirements, compliance shall be

determined based on measurements of the

combined filter effluent at four-hour

intervals.

2. Individual Filter Requirements. All

surface water systems that use rapid granular

filtration, serve more than 10,000 people, and

are required to filter shall conduct

continuous monitoring of turbidity for each

individual filter and shall provide an

exceptions report to the State on a monthly

basis. Exceptions reporting shall include the

following: (1) any individual filter with a

turbidity level greater than 1.0 NTU based on

2 consecutive measurements fifteen minutes

apart; and (2) any individual filter with a

turbidity level greater than 0.5 NTU at the

end of the first 4 hours of filter operation

based on 2 consecutive measurements fifteen

minutes apart. A filter profile will be

produced if no obvious reason for the

abnormal filter performance can be

identified.

If an individual filter has turbidity levels

greater than 1.0 NTU based on 2 consecutive

measurements fifteen minutes apart at any

time in each of 3 consecutive months, the

system shall conduct a self-assessment of the

filter utilizing as guidance relevant portions

of guidance issued by the Environmental

Protection Agency for Comprehensive

Performance Evaluation (CPE). If an

individual filter has turbidity levels greater

than 2.0 NTU based on 2 consecutive

measurements fifteen minutes apart at any

time in each of two consecutive months, the

system will arrange for the conduct of a CPE

by the State or a third party approved by the

State.

3. State Authority: States must have rules

or other authority to require systems to

conduct a Composite Correction Program

(CCP) and to assure that systems implement

any follow-up recommendations that result

as part of the CCP.

In reference to the above

recommendations, EPA also requests

comment on what would or would not

constitute an obvious reason for

abnormal filter performance. The

Agency also requests comment on how

much time a system should have to

conduct a self-assessment of the filter

and how much time a system should

have to arrange for the conduct of a CPE

under circumstances such as described

in the recommendations.

USEPA also requests comment on

whether there are particular filters

currently in operation in the United

States for which specific guidance may

be needed with regard to individual

filter monitoring. For example, some

members of the M-DBP Advisory

Committee suggested that special

guidance be developed for unique

filtration devices made by Infilco

Degremeont (previously made by

Aldridge). These devices consist of

multi-celled filters with a traveling

bridge-automated back washing unit

that are not conducive to individual cell

monitoring.

USEPA also requests comment

regarding existing SWTR provisions for

lime softening plants that have very low
59504 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

turbidity in source waters. The existing

SWTR allows States to set numerically

higher standards up to 1 NTU in 95

percent of samples taken per month for

conventional treatment and direct

filtration plants if the State determines

that on-site studies demonstrate at least

99.9 percent overall removal and/or

inactivation of Giardia cysts. (54 FR

27503). In the SWTR (54 FR 27486), the

Agency notes that actual demonstrations

‘‘(e.g. with pilot plant study results)’’ are

not required for the State to determine

when minimum performance

requirements at the higher turbidity

level might be appropriate for a

particular system. The SWTR states:

Instead, the State’s determination may be

based upon an analysis of existing design and

operating conditions (e.g. adequacy of

treatment prior to filtration, percent turbidity

removal across the entire treatment train,

stringency of disinfection) and/or

performance relative to certain water quality

characteristics (e.g. microbiological analysis

of the filtered water, particle size counts in

water before and after filtration). The State

may wish to consider such factors as source

water quality and system size in determining

the extent of analysis necessary. (54 FR

27503).

Committee members raised situations

where filtration plants have been

designed for specific source water

quality characteristics such as high

alkalinity and extremely low turbidity

water (e.g. 0.1 to 0.5 NTU). In systems

with such source waters, turbidity levels

from the filters may actually be higher

than in the source waters due to

reactions from chemicals added mainly

for purposes other than source water

particle removal. Lime softening plants

operating under certain conditions,

depending upon process configuration

and raw water characteristics or when

flocculation conditions change, may

periodically experience a carry over of

extremely fine calcium carbonate or

magnesium hydroxide particles. These

fine particles may pass through filters

thereby resulting in artificially elevated

effluent turbidity levels. If turbidity

performance criteria are tightened under

the IESWTR some plants may have

difficulty meeting these criteria but still

achieve substantial removal of Giardia

lamblia, Cryptosporidium parvum, and

viruses. As reflected in the 1989 SWTR,

USEPA believes that in cases where

lime softening is practiced and source

water turbidity levels are low,

provisions for alternative treatment

performance criteria (i.e., in lieu of

turbidity) may be appropriate.

As in the present SWTR, USEPA

believes that demonstrations of

equivalent protection need not be based

on actual demonstrations (e.g. pilot

plant study results). Instead the State’s

determination can be based on the

factors cited at 54 FR 27503 as quoted

above. Other factors related to source

water microbial quality (e.g. pristine

source water, source water protection

programs, microbial monitoring results,

bank filtration) may be appropriate for

such determinations.

USEPA requests comment on the

appropriateness of continuing existing

provisions that provide States the

flexibility of approving higher turbidity

levels up to 1 NTU in 95 percent of

samples per month and up to 2 NTU

maximum turbidity for such plants, and

additionally seeks comments on:

• What types of plants might fall in this

category (e.g. softening plants designed for

color and hardness removal with very low

turbidity source waters);

• What demonstrations of equivalent

protection from Giardia lamblia,

Cryptosporidium parvum, and viruses are

appropriate (e.g. microbiological analysis of

the filtered water, monitoring results for

protozoans, watershed control, wellhead

protection programs);

• What additional or alternative

requirements States might place on such

systems to insure the objective of equivalent

protection from Giardia lamblia,

Cryptosporidium parvum, and viruses (e.g.

regular monitoring for protozoans in source

and or filtered water, or for other water

quality parameters, watershed control, well

head protection programs);

• Allowing systems to acidify turbidity

samples when calcium carbonate carry-over

exists to obtain true turbidity readings; and

• The appropriateness of including source

water microbial quality measurements or

surrogates as part of a State determination of

equivalent protection when considering

whether to authorize higher operating

turbidity levels.

D. Disinfection Benchmark for Stage 1

DBP MCLS

A fundamental principle of the 1992–

93 regulatory negotiation which was

reflected in the 1994 proposal for the

IESWTR was that new standards for

control of byproducts must not result in

significant increases in microbial risk.

This principle was also one of the

underlying premises of the M-DBP

Advisory Committee’s deliberations,

i.e., that existing microbial protection

must not be significantly reduced or

undercut as a result of systems taking

the necessary steps to comply with the

Stage 1 DBPR. The Advisory

Committee’s recommendations to meet

this key objective are discussed in this

section.

The approach outlined below

represents the recommendation of the

Advisory Committee to develop a

mechanism that is designed to assure

that pathogen control is maintained

while the Stage 1 DBPR provisions are

implemented. Briefly, the disinfection

benchmark addresses the three issues of

who must gather the necessary

information to evaluate current

practices, how the benchmark operates,

and finally, how the system and the

State work together to assure that

microbial control is maintained.

Based on data provided by systems

and reviewed by the TWG, the baseline

of microbial inactivation (expressed as

logs of Giardia lamblia inactivation)

demonstrated high variability.

Inactivation varied by several logs on a

day-to-day basis at any particular

treatment plant and by as much as tens

of logs over a year due to changes in

water temperature, flow rate (and

consequently contact time), seasonal

changes in residual disinfectant, pH,

and disinfectant demand (and

consequently disinfectant residual).

There were also differences between

years at individual plants.

To address these variations, the TWG

developed an approach for a system to

use to characterize disinfection practice;

the procedure is called profiling. In

essence, this approach allows a plant to

chart or plot its daily levels of Giardia

inactivation on a graph which, when

viewed on a seasonal or annual basis,

represents a ‘‘profile’’ of the plant’s

inactivation performance. The system

can use the profile to develop a baseline

or benchmark of inactivation against

which to measure possible changes in

disinfection practice. This approach

makes it possible for a plant that may

need to change practice to meet DBP

MCLs to assure no significant increase

in microbial risk. It provides the

necessary tool to allow plants to project

or measure the possible impacts of

potential changes in disinfection. Only

certain systems would be required to

develop a profile and keep it on file for

State review during sanitary surveys,

and only a subset of those required to

develop a profile would be required to

submit it to the State as part of a

package submitted when the system is

making significant changes to its

disinfection practice.

USEPA reiterates its request for

comment on the following

recommendations of the M-DBP

Advisory Committee that address the

three questions outlined above: (1) who

should develop a profile, (2) how a

profile is actually generated, and (3)

how the profile will be used.

1. Applicability

Systems would be required to prepare

a disinfection profile, if at least one of

the following criteria are met:
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59505

(1) TTHM levels are at least 80% of the

MCL (0.064 mg/l) as an annual average for

the most recent 12 month compliance period

for which compliance data are available prior

to November 1998 (or some other period

designated by the State). Monitoring would

be in accordance with current TTHM

requirements.

(2) Haloacetic acid (HAA5) levels are at

least 80% of the MCL (0.048 mg/l) as an

annual average for the most recent 12 month

period for which data are available (or some

other period designated by the State). In

connection with HAA5 monitoring, the

following provisions apply:

(a) Systems that have collected HAA5 data

under the ICR must use those data to

determine the HAA5 level, unless the State

determines that there is a more representative

annual data set.

(b) If the system does not have four

quarters of HAA5 data by the end of 90 days

following the IESWTR promulgation date, the

PWS must conduct HAA5 monitoring for

four quarters. This monitoring must comply

with the monitoring requirements included

in the DBP Stage 1 rule.

(The Advisory Committee

recommended a value of 80% of the

MCL because available data indicated

that DBP levels varied from year to year

due to many factors (e.g., changes in

source water quality, changes in water

demand). The Committee believed that

targeting a level 20% below the MCL

would include most systems that would

be expected to make changes to comply

with the TTHM and HAA5 MCLs on a

continuing basis. Also, USEPA

previously considered this target level at

the recommendation of the 1992 reg-neg

committee, to evaluate DBP Stage 1

compliance forecasts and costs, based

upon the judgement that most facilities

will take additional steps to ensure

continuing MCL compliance if they are

at or above these levels.)

2. Developing the Profile and

Benchmark

As outlined above, profiling is the

characterization of a system’s

disinfection practice over a period of

time. The system can create the profile

by conducting new daily monitoring or

by using ‘‘grandfathered’’ data (as

explained below). A disinfection profile

consists of a compilation of daily

Giardia lamblia log inactivations (or

virus inactivations under conditions to

be specified in the final rule), computed

over the period of a year, based on daily

measurements of operational data

(disinfectant residual concentration(s),

contact time(s), temperature(s), and

where necessary, pH(s)).

Grandfathered data are those

operational data that a system

previously collected at a treatment plant

during the course of normal operation.

These data may or may not have been

used previously for compliance

determinations with the SWTR. Those

systems that have all necessary data to

determine profiles, using operational

data collected prior to promulgation of

the IESWTR, would be able to use up to

three years of operational data in

developing profiles. Grandfathered

operational data should be substantially

equivalent to operational data that

would be collected under this rule.

Those systems that do not have three

years of operational data to develop

profiles would have to conduct

monitoring to develop the profile for

one year beginning no later than 15

months after IESWTR promulgation. If

the PWS has existing operational data to

develop profiles, it would have to use

those data to develop profiles for the

years prior to the IESWTR

promulgation.

In order to develop the profile, a

system would have to:

—Measure disinfectant residual

concentration (C, in mg/l) prior to

entrance into distribution system and

just prior to each additional point of

disinfectant addition, whether with

the same or a different disinfectant.

—Determine contact time (T, in

minutes) during peak flow conditions.

T can be based on either a tracer study

or assumptions based on contactor

geometry and baffling. However,

systems would have to use the same

method for both grandfathered data

and new data.

—Measure water temperature (°C).

—Measure pH (for chlorine only).

The system would then have to

convert operational data to log

inactivation values for Giardia (and

viruses when chloramines or ozone

used as primary disinfectant).

—Determine CTactual for each

disinfection segment.

—Determine CT99.9 (i.e., 3-logs

inactivation) from tables in the

SWTR/IESWTR using temperature

(and pH for chlorine) for each

disinfection segment. [NOTE: USEPA

may redesign the tables so that no

conversion is necessary (i.e., the

tables will reflect a CT90 (1-log)

value.]

—For each segment, log inactivation =

(CTact/CT99.9) × 3.0.

A log inactivation benchmark would

then be calculated as follows:

1. Calculate the average log

inactivation for each calendar month.

2. Determine the calendar month with

the lowest average log inactivation.

3. The lowest average month becomes

the critical period for that year.

4. If 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 for that year is the

benchmark.

3. State Review

The State would review disinfection

profiles as part of its periodic sanitary

survey. If a system that is required to

develop a disinfection profile

subsequently decides to make a

significant change in disinfection

practice, it would have to consult with

the State before implementing such a

change. Significant changes would be

defined as: (1) moving the point of

disinfection, (2) changing the type of

disinfectant, (3) changing the

disinfection process, or (4) making any

other change designated as significant

by the State. Supporting materials for

such consultation would have to

include a description of the proposed

change, the disinfection profile, and an

analysis of how the proposed change

will affect the current disinfection

benchmark.

4. Guidance

USEPA, in consultation with

interested stakeholders, will develop

guidance for States and systems on how

to develop and evaluate disinfection

profiles, how to identify and evaluate

significant changes in disinfection

practices, and guidance on moving the

point of disinfection from before the

point of coagulant addition to after the

point of coagulant addition. USEPA will

also develop guidance for systems that

would be required to develop a profile

based on virus inactivation instead of

Giardia lamblia inactivation. Guidance

will be available when the IESWTR is

promulgated.

5. Request for Public Comment

USEPA requests comment on all

aspects of the recommendation outlined

above and any alternative suggestions

that stakeholders or other interested

parties may have. Commenters may

want to focus particular attention on the

following issues:

—Applicability requirements,

—Characterization of disinfection

practices and components (e.g.,

monitoring, analysis),

—Use of TTHM and HAA5 data from

the same time period instead of

TTHM data from one year and HAA5

data from another,

—Definition of significant changes to

disinfection practice,

—Different approaches to evaluating

possible changes in disinfection

practice against a disinfection profile,

and

—Whether the use of grandfathered

data, if available, should be
59506 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

mandatory for profiling and

benchmarking.

E. Definition of Ground Water Under the

Direct Influence of Surface Water

(GWUDI)—Inclusion of

Cryptosporidium in the Definition

1. Summary of 1994 Proposal and

Public Comments

The July 29, 1994, Federal Register

notice proposed to amend the SWTR by

including Cryptosporidium in the

definition of a GWUDI system. Under

the rule, a system using ground water

considered vulnerable to

Cryptosporidium contamination would

be subject to the provisions of the

SWTR. USEPA proposed that this

determination be made by the State for

individual sources using Stateestablished criteria.

The 1994 proposed IESWTR also

requested comment on revisions to

USEPA’s guidance on this issue.

Cryptosporidium oocysts are smaller

than Giardia cysts and may have

substantially different hydrodynamic

behavior in ground water due to their

smaller size and perhaps also due to a

difference in charge distribution on the

outer surface of the oocyst. USEPA

guidance for the determination of

GWUDI suggests methods that may be

insensitive to this differing

hydrodynamic behavior in ground

water.

Almost all commenters agreed that

Cryptosporidium should be added to the

definition. Only one commenter clearly

opposed the addition without caveat,

maintaining that problems with the

analytical methods for the recovery and

enumeration of viable organisms and

uncertainties associated with risk

assessment should preclude its

addition. One commenter contended

that Cryptosporidium should be

included only if USEPA addresses the

amount of natural disinfection at each

site and defines treatment effectiveness,

especially coagulant use, for GWUDI

systems. One commenter believed that

the definition of Cryptosporidium

should be made at the species level, e.g.

Cryptosporidium parvum, because other

species were not pathogenic to humans.

One commenter was concerned about

the Microscopic Particulate Analysis

(MPA), one of the methods that USEPA

identifies in guidance as being suitable

for making GWUDI determinations. As

part of this method, a microscopic

examination is made of the ground

water to determine whether insect parts,

plant debris, rotifers, nematodes,

Giardia lamblia, and other material

associated with the surface or near

surface environment are present. The

commenter claimed that the MPA has

analytical method problems similar to

those associated with the recovery of

cysts and oocysts from environmental

samples and suggested that the method

should undergo additional testing with

positive and negative controls and with

performance evaluation samples.

2. Overview of Existing Guidance

USEPA issued guidance on the MPA

in October 1992 as the Consensus

Method for Determining Groundwater

Under the Direct Influence of Surface

Water Using Microscopic Particulate

Analysis. Additional guidance for

making GWUDI determinations is also

available (USEPA, 1994e,f). Since 1990,

States have acquired substantial

experience in making GWUDI

determinations and have documented

their approaches (Massachusetts

Department of Environmental

Protection, 1993; Maryland, 1993;

Sonoma County Water Agency, 1991).

Guidance on existing practices

undertaken by States in response to the

SWTR may also be found in the State

Sanitary Survey Resource Directory,

jointly published in December 1995 by

USEPA and the Association of State

Drinking Water Administrators.

AWWARF has also published guidance

(Wilson et al., 1996).

3. Summary of New Data and

Perspectives

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.

USEPA is interested in an expanded

discussion of MPA performance. The

work cited here is preliminary

information and represents the only

data provided to USEPA so far. USEPA

is considering several analytical

activities to address possible changes in

the GWUDI determination guidance.

These changes are as follows:

• Change the MPA methodology to

include a score for Cryptosporidium

oocysts in the risk rating method.

• Conduct additional comparison of

MPA scores with cyst and oocyst

recovery to evaluate the performance of

MPA as an indicator method (e.g.,

Schulmeyer, 1995).

• Conduct additional MPA

performance evaluation testing (with

both positive and negative controls).

• Compare MPA scores and cyst/

oocyst recovery in horizontal collector

wells and vertical wells to determine if

additional guidance for horizontal

collector wells is needed.

4. Request for Public Comment

USEPA is continuing to consider

inclusion of Cryptosporidium in the

definition of GWUDI. USEPA requests

further comment on this issue as well as

on issues outlined above pertaining to

guidance for GWUDI determinations.

F. Inclusion of Cryptosporidium in

Watershed Control Requirements

1. Summary of 1994 Proposal and

Public Comments

USEPA proposed to extend the

existing watershed control requirements

for unfiltered systems to include the

control of Cryptosporidium. This would

be analogous to and build upon the

existing requirements for Giardia

lamblia and viruses; Cryptosporidium

would be included in the watershed

control provisions wherever Giardia

lamblia is mentioned. USEPA also

proposed requiring a State, as a

condition of primacy, to describe how it

would judge the adequacy of watershed

control programs for Cryptosporidium

as well as Giardia lamblia and viruses

in the source water.

Several commenters to the proposed

rule specifically supported inclusion of

Cryptosporidium in watershed control.

Others supported watershed control

programs in general without specifically

articulating an opinion on

Cryptosporidium. One commenter

specifically opposed the inclusion of

Cryptosporidium in watershed control

program, maintaining that other avenues

of watershed control could be promoted

without including this organism in the

control plan. Another commenter

opposed including Cryptosporidium

because environmental sources of

Giardia and Cryptosporidium were not

sufficiently understood. This

commenter also opposed the

requirement to include Cryptosporidium
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59507

in State watershed control program

protocols as a condition of primacy.

Other comments included: (1)

Systems need to be informed of the

nature of upstream pathogen sources

and changes in upstream water quality

in a timely manner, (2) watershed

characteristics should not be the sole

basis for determining water treatment

strategies, (3) upstream sewage

discharges should be prohibited and

cattle farming and feedlots prohibited or

substantially limited in a watershed,

and (4) watershed control programs

should be scientifically based,

educational, and voluntary. One

commenter contended that the burden

of contamination on the watershed

should not fall to the drinking water

systems, and that better coordination on

regulations is needed between the

USEPA’s drinking water and wastewater

programs.

2. Overview of Existing Guidance

The SWTR specifies the conditions

under which a system can avoid

filtration (40 CFR 141.71). These

conditions include good source water

quality, as measured by concentrations

of coliforms and turbidity, disinfection

requirements; watershed control;

periodic on-site inspections; the absence

of waterborne disease outbreaks; and

compliance with the Total Coliform

Rule and the MCL for TTHMs.

The watershed control program under

the SWTR must minimize the potential

for source water contamination by

Giardia lamblia and viruses. This

program must include a characterization

of the watershed hydrology

characteristics, land ownership and

activities which may have an adverse

effect on source water quality. The

SWTR Guidance Manual (USEPA,

1991a) identifies both natural and

human-caused sources of contamination

to be controlled. These sources include

wild animal populations, wastewater

treatment plants, grazing animals,

feedlots, and recreational activities. The

Guidance Manual recommends that

grazing and sewage discharges not be

permitted 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.

3. Summary of New Data and

Perspectives

Since proposal of the IESWTR in July

1994, several new outbreaks of

waterborne cryptosporidiosis have

occurred in the United States. A recent

summary of these outbreaks (SoloGabriele and Neumeister, 1996)

identified raw sewage, surface runoff

from livestock grazing areas, septic tank

effluent, cattle wastes, treated

wastewater, and backflow of

contaminated water in the distribution

system as the suspected sources of

Cryptosporidium contamination of the

water supplies in these outbreaks. Cattle

grazing, feedstocks and in particular,

calves and other young livestock, appear

to be of greater concern for

Cryptosporidium contamination than for

Giardia. Some outbreaks of

cryptosporidiosis have been related to

upsets in the treatment process of

filtered water systems or have occurred

on occasions when spikes in turbidity

have occurred in those systems.

However, little information is available

for unfiltered water systems as to

whether spikes in raw water turbidity

increase the likelihood that elevated

levels of Cryptosporidium are present in

the source water. Because

Cryptosporidium cannot easily be

controlled with conventional

disinfection practices, there is particular

concern about the presence of this

organism in the source waters of

systems that do not filter.

Data from the ICR may be useful in

providing information on the relative

Giardia and Cryptosporidium levels in

the raw water sources of unfiltered and

filtered water systems. In one

comprehensive study on Giardia and

Cryptosporidium densities in ambient

water and drinking water, investigators

(LeChevallier and Norton, 1995) found

Cryptosporidium oocyst levels in

ambient water ranging from 0.065/L to

65.1/L, with a geometric mean of 2.4

oocysts/L. In drinking water, the level of

Cryptosporidium oocysts ranged from

0.29–57 oocysts/100L, with a mean of

3.3 oocysts/100L.

The Seattle Water Department

summarized the Giardia and

Cryptosporidium monitoring results

from several unfiltered water systems

(Montgomery Watson, 1995). The

central tendency of this data is about 1

oocyst/100L. Thus, depending upon

what removal efficiencies are achieved

by filtration for Cryptosporidium (for

example, 2 logs), it appears that

unfiltered water systems that comply

with the source water requirements of

the SWTR may have a risk of

cryptosporidiosis equivalent to that of a

water system with a well-operated filter

plant using a water source of average

quality.

Although there are no specific

monitoring requirements in the

watershed protection program, the nonfiltering utility is required to develop

state-approved techniques to eliminate

or minimize the impact of identified

point and non-point sources of

pathogenic contamination. USEPA is

considering adding specific monitoring

requirements to the IESWTR for the

unfiltered supplies serving 10,000 or

more people to ensure the continued

effectiveness of the watershed control

program. The monitoring would be

similar to the requirements under the

ICR for Giardia and Cryptosporidium

although the sampling frequency may be

modified. As with the ICR, a USEPAapproved method and laboratory for

Giardia and Cryptosporidium analyses

would be required.

At a minimum, such a monitoring

program might require some level of

routine sampling (e.g., on a weekly,

biweekly or monthly basis). The

program may also include ‘‘event’’

sampling. An ‘‘event’’ would constitute

an occasion when the raw water

turbidity and/or fecal/total coliform

concentration exceeded a specific value

or possibly exceeded a site-specific 90th

percentile value. At least one sample

during an event might be required in

addition to routine sampling. Results of

all protozoa and related analyses would

be made available to the State at a

minimum as part of the annual on-site

inspection required under the SWTR for

non-filtering supplies.

USEPA is continuing to consider

extending the existing watershed

control requirements for unfiltered

systems to include the control of

Cryptosporidium. USEPA requests

further comment on this issue. The

Agency also requests comment on issues

pertaining to monitoring for unfiltered

systems serving 10,000 or more people,

including comment on the following

approaches:

Routine Source Water Giardia and

Cryptosporidium Monitoring:

Option 1. Weekly Giardia and

Cryptosporidium Monitoring

Option 2. Bi-Weekly Giardia and

Cryptosporidium Monitoring

Option 3. Monthly Giardia and

Cryptosporidium Monitoring

The Agency also requests comments on

whether the frequency of monitoring

should depend on system size, e.g.,

should requirements differ for systems

serving between 10–100,000 people

versus those serving more than 100,000

people.

‘‘Event’’ Source Water Giardia and

Cryptosporidium Monitoring:

Option 1. No event sampling required.

Option 2. Collect sample(s) for

Giardia and Cryptosporidium when

source water turbidity exceeds 1.0 NTU

or some alternative value such as a site-
59508 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

specific 90th percentile which might be

lower than 1.0 NTU.

Option 3. Collect sample(s) for

Giardia and Cryptosporidium when

source water fecal coliform

concentration exceeds 20 per 100 mL or

total coliform level exceeds 100 per 100

mL, depending on which class of

coliforms is used under the individual

systems filtration avoidance agreement.

Alternatively, the trigger could be some

other coliform or fecal coliform value.

Option 4. Individual utility develops

turbidity frequency distribution (e.g.,

based on previous 1 to 3 years of daily

historical data) and collects sample(s)

for Giardia and Cryptosporidium when

turbidity exceeds 90th percentile level.

Option 5. Some combination of

Options 2, 3, or 4.

The Agency also requests comment on

whether any of the above options

should depend on system size.

G. Sanitary Survey Requirements

1. Summary of 1994 Proposal and

Public Comments

The July 29, 1994, Federal Register

proposed to amend the SWTR to require

periodic sanitary surveys for all public

water systems that use surface water, or

ground water under the direct influence

of surface water, regardless of whether

they filter or not. States would be

required to review the results of each

sanitary survey to determine whether

the existing monitoring and treatment

practices for that system are adequate,

and if not, what corrective measures are

needed to provide adequate drinking

water quality.

The July 1994 notice proposed that

only the State or an agent approved by

the State would be able to conduct the

required sanitary survey, except in the

unusual case where a State has not yet

implemented this requirement, i.e., the

State had neither performed the

required sanitary survey nor generated a

list of approved agents. The proposal

suggested that under exceptional

circumstances the sanitary survey could

be conducted by the public water

system with a report submitted to the

State within 90 days. USEPA also

requested comment on whether sanitary

surveys should be required every three

or every five years.

Most commenters on this issue voiced

support for requiring a periodic sanitary

survey for all systems. One commenter

suggested that USEPA develop sanitary

survey guidance for administration by

the States, while another commenter

suggested that sanitary surveys by the

private sector be certified by States or

national associations using USEPAdefined criteria. Commenters

recommended that surveys be

conducted either by the State or a

private independent party/contractor.

One respondent contended that sanitary

surveys, as presently conducted, were

insufficient to assess operational

effectiveness in surface water systems.

With regard to sanitary survey

frequency, commenters were nearly

evenly divided between every three

years and every five years. Some

commenters argued that the frequency

should depend on: (1) whether a

system’s control is effective or marginal,

(2) system size (less frequent for small

systems), (3) source water quality, (4)

whether the State believes a system’s

water quality is likely to change over

time, (5) results of the previous survey,

and (6) population density on the

watershed. One commenter suggested

an annual sanitary survey.

Regarding criteria for sanitary survey

inspectors, some commenters suggested

that the State should decide what

requirements to use. Others suggested

some combination of education and

working experience related to water

plant operations, including (1)

professional engineering certificate and

water plant operator license for at least

five years, (2) knowledge of surface

water contaminants, source and fate of

contaminants, and both removal

capabilities of existing treatment

technologies and ability to evaluate

their performance, (3) a BS degree

(preferably MS degree) in sanitary or

environmental engineering with two

years experience in evaluating water

treatment plants and valid plant

operator’s license, (4) five years

experience in water system operation,

evaluation, and/or design, and a BS in

engineering or environmental science,

(5) a BS degree in science or engineering

and five years experience in the

drinking water field.

2. Overview of Existing Regulations and

Guidance

Sanitary surveys have historically

been conducted by state drinking water

programs as a preventive tool to identify

water system deficiencies that could

pose a threat to public health. The first

regulatory requirement for systems to

have a periodic on-site sanitary survey

appeared in the final TCR (54 FR

27544–27568). This rule requires all

systems that collect less than 5 total

coliform samples each month to

undergo such surveys. These sanitary

surveys must be conducted by the State

or an agent approved by the State.

Community water systems were to have

had the first sanitary survey conducted

by June 29, 1994, and every five years

thereafter while non-community water

systems are to have the first sanitary

survey conducted by June 29, 1999, and

every five years thereafter unless the

system is served by a protected and

disinfected ground water supply, in

which case, a survey must be conducted

every 10 years.

The SWTR did not specifically

require water systems to undergo a

sanitary survey. Instead, it required that

unfiltered water systems, as one

criterion to remain unfiltered, have an

annual on-site inspection to assess the

system’s watershed control program and

disinfection treatment process. The onsite survey must be conducted by the

State or a party approved by the state.

This on-site survey is not a substitute

for a more comprehensive sanitary

survey, but the information can be used

to supplement a full sanitary survey.

USEPA’s SWTR Guidance Manual

(USEPA, 1991a), Appendix K, suggests

that, in addition to the annual on-site

inspection, a sanitary survey be

conducted every three to five years by

both filtered and unfiltered systems.

This time period is suggested ‘‘since the

time and effort needed to conduct the

comprehensive survey makes it

impractical for it to be conducted

annually.’’

3. New Developments

Since the publication of the proposed

ESWTR in 1994, USEPA and the States

(through the Association of State

Drinking Water Authorities) have issued

a joint guidance on sanitary surveys

entitled USEPA/State Joint Guidance on

Sanitary Surveys (1995). The Guidance

outlines the following elements as

integral components of a comprehensive

sanitary survey:

• Source

—Protection

—Physical Components and

Condition

• Treatment

• Distribution System

• Finished Water Storage

• Pumps/Pump Facilities and Controls

• Monitoring/Reporting/Data

Verification

• Water System Management/

Operations

• Operator Compliance with State

Requirements

The guidance also addresses the

qualifications for sanitary survey

inspectors, the development of

assessment criteria, documentation,

follow-up after the survey, tracking and

enforcement.

USEPA is aware that a number of

States have independently developed

their own sanitary survey criteria. For

instance, the American Water Works

Association California-Nevada Section,
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Source Water Quality Committee in

conjunction with the California

Department of Health Services, Division

of Drinking Water and Environmental

Management (DHS) have published a

document entitled Watershed Sanitary

Survey Guidance Manual (AWWA

California -Nevada Section 1993) to

assist domestic water suppliers in

defining the scope of their watershed

sanitary surveys and to provide

information on the methods and sources

of information for conducting sanitary

surveys.

4. Advisory Committee

Recommendations and Related Issues

USEPA reiterates its request for

comment on the following

recommendations of the M–DBP

Advisory Committee.

A sanitary survey would be defined as an

onsite review of the water source (identifying

sources of contamination using results of

source water assessments where available),

facilities, equipment, operation,

maintenance, and monitoring compliance of

a system to evaluate the adequacy of the

system, its sources and operations and the

distribution of safe drinking water. Included

in this definition is the concept that

components of a sanitary survey may be

completed as part of a staged or phased State

review process within the established

frequency interval set forth below. Finally,

for a sanitary survey to fall within this

definition, it must address each of the eight

elements in the December 1995 USEPA/State

Guidance on Sanitary Surveys.

In terms of frequency, this approach would

provide that sanitary surveys must be

conducted for all surface water systems

(including ground water under the influence)

no less frequently than every three years for

community systems and no less frequently

than every five years for noncommunity

systems. Any sanitary survey conducted after

December 1995, that addresses the eight

sanitary survey components of the 1995 EPA/

State guidance, may be counted or

‘‘grandfathered’’ for purposes of completing

the round of surveys. This approach would

also provide that for community systems

determined by the State to have outstanding

performance based on prior sanitary surveys,

successive sanitary surveys may be

conducted no less than every five years.

Finally, under this approach, as part of

follow-up activity for sanitary surveys,

systems must respond to deficiencies

outlined in the State’s sanitary survey report

within 45 days, indicating how and on what

schedule the system will address significant

deficiencies noted in the survey. In addition,

States must have the appropriate rules or

other authority to assure that facilities take

the steps necessary to address significant

deficiencies identified in the survey report

that are within the control of the PWS and

its governing body.

USEPA also requests comment on

whether systems should be required to

respond in writing to a State’s sanitary

survey report discussed in the

paragraph above. USEPA also requests

comment on (1) what would constitute

‘‘outstanding performance’’ for purposes

of allowing sanitary surveys for a

community water system to be

conducted every five years and (2) how

to define ‘‘significant deficiencies.’’

H. Covered Finished Water Reservoirs

1. Summary of the 1994 Proposal and

Public Comments Received

The July 29, 1994, Federal Register

indicated that USEPA was considering

whether to issue regulations requiring

systems to cover finished water

reservoirs and storage tanks, and

requested public comment. The

rationale for this position was given in

the proposed rule.

Most commenters supported either

federal or State requirements. Some

commenters suggested that regulations

apply only to new reservoirs. Some

commenters opposed any requirement,

citing high cost, the notion that ‘‘one

size does not fit all’’, and aesthetic

benefits of an open reservoir.

Some commenters suggested elements

for such regulations or guidance,

including (1) applying the same criteria

to finished water reservoirs as exists for

unfiltered surface water systems, (2)

using engineering measures to minimize

contamination, (3) disinfecting the

effluent to maintain residual in

distribution system, (4) monitoring

reservoirs routinely for water quality

indicators, (5) covering all storage tanks,

(6) fencing reservoirs with signs

warning against swimming, trespassing,

and tampering, and (7) adding notices in

the annual water quality report that the

reservoir is not in compliance with

current waterworks standards. A few

commenters suggested a number of

other elements.

2. Overview of Existing Information

Possible Health Concerns: When a

finished water reservoir is open to the

atmosphere it may be subject to some of

the environmental factors that surface

water is subject to, depending upon sitespecific characteristics and the extent of

protection provided. It may be subject to

contamination by persons tossing items

into the reservoir or illegal swimming

(Pluntze 1974; Erb, 1989).

Microscopic and other organisms may

proliferate in open finished water

reservoirs. Increases in algal cells,

heterotrophic plate count (HPC)

bacteria, turbidity, color, particle

counts, biomass and decreases in

chlorine residuals have been reported

(Pluntze, 1974, AWWA Committee

Report, 1983, 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.,

1996; Geldreich, 1990; Fayer and Ungar,

1986; Current, 1986). Mammals, birds

and fish and their carcasses seed the

water and the sediment with total and

fecal coliforms, E. coli and pathogens. In

one study, sea gulls contaminated a 10

million gallon reservoir and increased

bacteriological growth and in another

study waterfowl were found to elevate

coliform levels in small recreational

lakes by twenty times their normal

levels (Morra, 1979). Seagulls are a

source of numerous coliforms and can

also be a source for several human

pathogens, (Geldreich and Shaw, 1993).

Algal growth increases the biomass in

the reservoir, which reduces dissolved

oxygen and thereby increases the release

of iron, manganese, and nutrients from

the sediments. This, in turn, supports

more growth (Cooke and Carlson, 1989).

Plants, macrophytes and organic debris

will add to the biomass and nutrient

supply.

State Regulations: In order to assess

regulatory requirements at the State

level, it is necessary to contact

individual drinking water programs and

collect and evaluate specific regulatory

language obtained from those programs.

A survey of nine States was conducted

in the summer of 1996 (Montgomery

Watson, 1996). The States which were

surveyed included several in the West

(Oregon, Washington, California, Idaho,

Arizona, and Utah), two States in the

East known to have water systems with

open reservoirs (New York and New

Jersey), and one midwestern state

(Wisconsin). Seven of the nine States

which were surveyed require by direct

rule that all new finished water

reservoirs and tanks be covered.

Survey of Ten Utilities: There is no

comprehensive information available on

the number or size of open finished

water reservoirs in water systems

around the country; however, there is

one recent survey of ten utilities which

either have open finished water

reservoirs or which had them in the past

and covered or replaced them (E&S

Environmental Chemistry, 1997). The

existing open reservoirs which were

operated by these systems varied greatly

in size, from 5.5 million gallons (MG) to

900 MG. The systems with open

finished reservoirs also had closed

reservoirs within their service area, but

for some of the systems the open

reservoirs represent the largest

component of total storage volume in

the systems.
59510 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

Most of the reservoirs in the systems

in this survey were excavated and lined,

but several of the larger ones were

formed by dams or natural lakes that

had been converted to water supply use.

Many of these reservoirs have irregular

geometry and configurations which

make covering very difficult or

impossible. Others are so large that

covering them would be impractical.

For some of these reservoirs, it is

impractical to find locations for

replacement with the proper hydraulic

characteristics and size. To partially

solve this problem in some cases,

systems have chosen to leave large

existing open reservoirs off-line, except

for emergency supply purposes.

None of the systems had

comprehensive evidence about the

effect of open reservoirs on water

quality. These water systems had

instituted a number of measures at open

reservoirs to control potential sources of

contamination; these measures included

fencing setbacks, security cameras, onsite surveillance, rechlorination, wire

canopies to control bird activity, and

other measures.

3. Request for Public Comment

USEPA is considering as part of the

IESWTR a requirement that systems

cover all new reservoirs, holding tanks

or other storage facilities for finished

water for which construction begins

after the effective date of the rule. The

Agency intends to further consider this

issue, including whether there should

be a requirement that all finished water

reservoirs, holding tanks and other

storage facilities be covered, as part of

the development of the Long-Term

ESWTR. The Agency requests further

comment on this issue and whether

provisions should be established to

require all new reservoirs, holding

tanks, or other storage facilities to be

covered.

I. Cross Connection Control Program

1. Summary of 1994 Proposal and

Public Comments

The July 29, 1994, Federal Register

requested public comment on whether

the Agency should require States and/or

systems to have a cross-connection

control program. In addition, the

Agency solicited comment on a number

of associated issues, including (1) what

specific criteria, if any, should be

included in such a requirement, (2) how

often such a program should be

evaluated, (3) whether USEPA should

limit any requirement to only those

connections identified as a cross

connection by the public water system

or the State, and (4) conditions under

which a waiver from this requirement

would be appropriate. The Agency also

requested commenters to identify other

regulatory measures USEPA should

consider to prevent contamination of

drinking water in the distribution

system (e.g., minimum pressure

requirements in the distribution

system).

Most commenters supported either a

federal or State cross connection control

program. Various commenters

recommended that such a program

include a backflow prevention program

with approved backflow preventer lists,

categorization of all service connections

with respect to potential risk of

backflow, requirement for periodic

testing and maintenance of backflow

prevention devices, periodic review of

program by State, establishment of an

annual backflow device testing program,

establishment of a backflow device

inspector certification program,

enforcement authority, and other

suggestions. Commenters also

recommended national disinfection

procedures for repair of water lines and

for placing new lines into service, a

provision for at least one person trained

in cross-connection control to carry out

the program, and other suggestions.

Commenters opposed to a cross

connection control program indicated

that (1) a federally-mandated program

would be impractical, burdensome, and

would fail, (2) a State program would be

more appropriate than an USEPAmandated program, (3) most States

already have a comprehensive program,

thus negating need for federal

regulations, (4) USEPA should publish

general guidelines only, and (5) there

should be a separate regulation because

a cross connection control program

would affect both surface water and

ground water.

2. Overview of Existing Information

Historically, a significant portion of

waterborne disease outbreaks reported

by CDC are caused by distribution

system deficiencies. Distribution system

deficiencies are defined in CDC’s

publication Morbidity and Mortality

Weekly Report as cross connections,

contamination of water mains during

construction or repair, and

contamination of a storage facility.

Between 1971–1994, approximately 53

waterborne disease outbreaks were

associated with cross connections or

backsiphonage. Fifty-six outbreaks were

associated with other distribution

system deficiencies (Craun, Pers. Comm.

1997b). Some outbreaks have resulted

from water main breaks or repairs.

There is no centralized repository

where backflow incidents are reported

or recorded. The vast majority of

backflow incidents are probably not

reported. Specific backflow incidents

are described in detail in USEPA’s

Cross-Connection Control Manual

(USEPA, 1989a).

Where cross connections exist, some

protection is still afforded to the

distribution system by the maintenance

of a positive water pressure in the

system. Adequate maintenance of

pressure provides a net movement of

water out through breaks in the

distribution pipes and prevents

contaminated water outside of the pipes

from entering the drinking water

supply. The loss of pressure in the

distribution system, less than 20 psi,

can cause a net movement of water from

outside the pipe to the inside, possibly

allowing the introduction of fecal

contamination into the system. This

problem is of special concern where

wastewater piping is laid in the same

street as the water pipes, creating a

potential threat to public health

whenever there is low or no pressure.

Many States have cross connection

control programs. A Florida Department

of Environmental Protection survey

evaluated cross-connection control

regulations in the 50 states (Florida DEP

1996). The survey results showed that

29 of the 40 states that responded to the

survey request have programs. The rigor

of the programs and the extent to which

they are enforced was not addressed by

the survey. An USEPA report suggests

that the responsibility for

administration and enforcement of the

State programs is generally at the local

level (USEPA, 1995a).

3. Request for Public Comment

USEPA does not plan to address cross

connection control in the IESWTR. As

noted above, many States currently have

programs, although the extent to which

these vary is unclear. The Agency does

plan to consider cross connection

control issues during the development

of the Long-Term ESWTR, in the context

of a broad range of issues related to

distribution systems. USEPA continues

to request comments or additional

information related to cross connection

control or other distribution system

issues.

J. Recycling Filter Backwash Water and

Filtering to Waste

The July 29, 1994, notice requested

comment on the extent to which the

ESWTR should address the issue of

recycling filter backwash water, given

its potential for increasing the densities

of Giardia and Cryptosporidium on the

filters. The 1996 Amendments to the

SDWA require USEPA to promulgate a
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59511

regulation for filter backwash recycling

not later than August 2000, (SDWA

1412(b)(14)).

Most commenters who addressed this

issue contended that backwash water

should not be recycled or that, if it is

recycled, it should be treated first. One

commenter suggested that this decision

should be based on the pathogen

density in the backwash water. Another

commenter suggested that the rule

should include criteria for assessing the

extent of backwash recycling,

depending on raw water quality, size of

filters, and water volume. Another

commenter maintained that this issue

should be left to the State and system.

One commenter suggested that the

impacts of recycling needed additional

research and that any rule addressing

this issue needed to incorporate the

results of the latest research.

1. Filter Backwash Recycle

Configurations

Treatment plants can be configured

into several general categories but the

variation within each category is

significant.

One aspect of this treatment variation

is how recycling of waste streams from

plant processes are handled. Figure 4

shows a general schematic of a

conventional treatment plant and how

recycle streams may be developed and

treated. Note that backwash water

treatment is carried out in a miniature

coagulation-flocculation-sedimentation

treatment facility. Some utilities are

considering microfiltration to replace

these unit processes.

BILLING CODE 6560–50–P
59512 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

BILLING CODE 6560–50–C
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59513

Figure 5 shows an alternate view for

some water treatment facilities that do

not practice treatment of their recycled

waste streams. There is an almost

infinite variety between these two

examples. In addition, waste streams

can be recycled to many different points

in the treatment train. The most

common recycle points are at the plant

influent or rapid mix. However, there

are several known examples of recycle

streams being introduced into the

treatment process as late as the filter

influent.

BILLING CODE 6560–50–P

BILLING CODE 6560–50–C

Figure 6 shows a typical plot of

turbidity over time from a filter from

reintroduction into service after

backwash to breakthrough of turbidity at

the end of the filter run. Some plants

have installed filter-to-waste facilities

which allow the discharge of the first

minutes of a filter’s operation after

backwashing usually into the backwash

reclamation system. In California, the

State drinking water regulations define

filter-to-waste as: ‘ ‘‘Filter-to-waste’’

means a provision in a filtration process

to allow the first filtered water, after

backwashing a filter, to be wasted or

reclaimed.’ (McGuire, 1994)

BILLING CODE 6560–50–P
59514 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

BILLING CODE 6560–50–C

Figure 7 shows a general schematic of

a filter-to-waste operation. After the

backwash process is complete and the

filter influent water is allowed to enter

the filter, Valve A is operated so that all

of the filter effluent water is sent to

waste. After a specified period of time

or when it is determined that the

ripening spike is largely over, Valve A

is operated so that the filtered water

becomes part of the product water of the

treatment plant.

BILLING CODE 6560–50–P
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59515

BILLING CODE 6560–50–C

2. State Drinking Water Regulations

California has specific regulations that

deal with backwash recycle and filterto-waste. Treatment of backwash recycle

flows is covered in the design of

treatment facilities section. For new

construction, utilities are required to

install solids removal treatment for

recycled filter backwash water. Also,

treated backwash water must be

returned to the ‘‘headworks’’ (i.e., the

plant influent) of the treatment plant.

Solids removal treatment unit processes

are not specified in the regulation, but

new construction must be approved by

the California Department of Health

Services (California Health and Safety

Code, Sections 646658 & 64660).

To minimize the filter ripening spike,

the California Department of Health

specifies operational requirements such

that filtration rates are increased

gradually when filters are placed back

into service following backwashing or

any other interruption in the operation

of the filter. When any individual filter

is placed back into service following

backwashing or other interruption

event, the filtered water turbidity from

that filter cannot exceed any of the

following criteria:

• 2.0 NTU.

• 1.0 NTU in at least 90 percent of the

interruption events during any

consecutive 12-month period.

• 0.5 NTU after the filter has been in

operation for 4 hours.

For new construction, utilities are

required to provide filter-to-waste or

add additional coagulant chemicals to

backwash water.

3. Literature Overview of Standard of

Practice

a. Treatment Reference Texts. The

joint ASCE/AWWA (1990) water

treatment plant design book includes

one section on page 182 dealing with

washwater disposal and recovery. The

section lists several possibilities

including recycling without treatment,

equalization and treatment, and lagoons

to provide for both equalization and

sedimentation. On page 188, the

backwash recycle facility at the Duluth,

Minnesota plant is described. Chemical

addition, flocculation and clarification

comprise the backwash treatment

system.

The fourth edition of Water Quality

and Treatment contains one section on

pages 988–989 dealing with filter

backwash residuals. The section notes

that recovery of ‘‘dirty’’ backwash water

is becoming increasingly common and

that the volume of backwash water is

typically one to five percent of total

plant production. Flow equalization is

listed as the most common approach to

dealing with recycling of backwash

water. The section states that ‘‘For

conventional plants, solid separation

before return is not common, and some

holding tanks are mixed to keep solids

in suspension.’’ Direct filtration plants

are noted for needing solids separation
59516 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

treatment of backwash water, because

there is no sedimentation facility in a

direct filtration plant. Concerns are

expressed in the section about

increasing the concentrations of Giardia

cysts in the plant influent with the

recycle of untreated backwash water.

A handbook of practice was published

in 1987 dealing with water treatment

plant waste management. Backwash

water was described as a major waste

stream on page 5 and flow equalization

was listed as an important requirement.

The handbook gives specific examples

of the size of backwash basins needed

based on the number of filters

backwashed and the backwash

frequency. The example discusses

tankage volumes that would allow a

maximum 10 percent recycle rate of the

backwash water to the plant influent.

Neither clarification nor polymer

addition were mentioned in this early

reference (Cornwell et al., 1987).

b. ICR Treatment Plants. Of the 523

treatment plants subject to the ICR, 282

use conventional treatment. Of the

conventional treatment plants, 146 (or

52%) practice recycling of their

backwash water. Additionally, 15 direct

filtration plants and 3 in-line filter

plants recycle their backwash water.

These data show that a large fraction of

the surface water treatment plants

recycle their backwash water.

The ICR will provide the first detailed

data on the number of treatment plants

that treat their recycled backwash water

and the technologies they use and some

limited data on backwash water quality.

Until the initial sampling plan data is

available for analysis sometime in early

1998, the only information available on

the ICR utilities is from their Initial

Sampling Schematics and that will only

show the addition of a treatment

chemical. The Initial Sampling

Schematics do not indicate if

coagulation, flocculation or

sedimentation is used for washwater

recycle treatment.

An inspection of those schematics

revealed the following information on

treatment of recycled backwash water. A

total of 164 schematics for plants using

conventional treatment, direct filtration

or in-line filtration were examined.

Only 12 of the plants indicated that they

provided any chemical treatment.

Addition of a polymer was practiced at

5 plants. Chlorination as the only

treatment of the recycled washwater

was found at 2 plants. A total of 5 plants

provided both chlorination and polymer

treatment of the backwash water.

c. Cornwell and Lee 1993 Report.

Another source of information on waste

stream quality and the impact of

recycling of these streams on treated

water quality is found in an American

Water Works Association Research

Foundation (AWWARF) 1993 report

authored by Cornwell and Lee. They

studied the quality characteristics of

waste streams from 24 treatment plants

and investigated the treatment

characteristics in some detail at 8

plants.

Among the contaminants analyzed

were Giardia and Cryptosporidium. The

study found that filter backwash water

could have very high cyst/oocyst

concentrations and chemical loads.

However, the researchers found no

finished water quality problems as a

result of recycling.

The study found that backwash water

sedimentation was effective in reducing

particle and pathogen concentrations in

the used filter backwash water.

However, very low overflow rates (less

than 0.05 gpm/sf) of the sedimentation

basin were required to achieve the

solids removal unless a polymer was

used. Using an anionic polymer

increased the particle removals and

allowed sedimentation overflow rates of

0.2 to 0.3 gpm/sf. The last two sentences

of the Executive Summary of the report

provide insight into the overall findings.

‘‘The use of equalized, continuous recycle,

proper waste stream treatment prior to

recycle, and characterization of waste stream

quality through proper monitoring should be

used in conjunction with recycle operations.

If these recommendations are used, recycle

can be an appropriate part of water treatment

operations (Cornwell and Lee, 1993).’’

In a paper which summarized the

report findings, the authors stated a

general rule that the recycle streams

should be flow equalized and blended

in to the plant flow over the entire 24

hour plant operating cycle. The rule of

thumb that the amount of recycle

should be less than 10 percent of the

plant flow may not be sufficient, and a

lower percentage of recycle may have to

be practiced depending on the quality of

the recycled water (Cornwell and Lee,

1994).

d. Other Studies. In 1996, AWWA

conducted a survey of treatment plants

to determine the extent of backwash

water recycling and the treatment

provided to that water (McGuire, 1997).

A total of 400 plants from utilities

serving more than 100,000 people were

contacted. About 40 percent of those

plants responded. Of those responding,

about 60 percent of the plants recycled

their filter backwash water. The other 40

percent appeared to discharge the

backwash water to a surface water

supply or to a sanitary sewer. Of the

plants that recycled their backwash

water, 27 percent responded that they

treated the recycle water. The important

point to note from this limited survey is

that recycle of backwash water appears

to be a common practice among water

treatment plants.

4. Filter-to-Waste

One possible concern is the discharge

of large number of particles from filters

that are put back into service after

backwashing. Work done on Giardia

removal by filtration at Fort Collins,

Colorado, indicated that a filter-to-waste

period was not necessary to produce

low Giardia filter effluent levels as long

as proper chemical preconditioning of

the filter was practiced (Gertig et al.

1988). Logsdon et al. studied

sedimentation and several different

filter media from removing Giardia cysts

at McKeesport, Pennsylvania. Giardia

cyst concentrations were found to be

higher at the beginning of the filter run,

indicating that filter-to-waste may be

needed to reduce the levels of Giardia

in the finished water (Logsdon et al,

1985).

One study (Amirtharajah, 1988)

indicated that more than 90% of the

particles that pass through a filter do so

during the initial stages of filtration.

Another study (Logsdon et al., 1981)

found that initial cyst concentrations in

the effluent, after backwash, were from

10 to 25 times higher than those in the

stabilized filter run, even though the

difference in turbidity was less than 0.1

NTU. One British study (Hall and Croll

1996) found that in one test filter run,

calculation of the total number of

particles released during the whole run

showed that up to 30% of the particles

were released during the first hour of

filter ripening. The turbidity during this

peak was 0.4 NTU. Gradual start of the

filter after backwashing reduced the

peak particle count in the effluent.

Effectiveness of practicing filter-towaste in reducing the passing of oocysts

depends on the duration of the ripening

period. For example, a 15 minute filterto-waste period will not be very

effective for a ripening period of 2

hours. Mid and end-of-run turbidity

spikes can also pass large number of

particles (including pathogen oocysts)

into the effluent. However, these latter

spikes can be controlled by avoidance of

flow changes and by timely

backwashing the filter.

5. Request for Public Comment

USEPA does not plan to include

separate provisions for recycling of filter

backwash water and filter-to-waste

issues in the IESWTR. The Agency

anticipates that some systems will

address these issues as part of their

efforts to comply with revised turbidity

performance standards of 0.3 NTU for
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59517

the 95th percentile of monthly

measurements and a maximum turbidity

level of 1 NTU. As previously discussed

in this Notice, USEPA is required under

the 1996 Amendments to the SDWA to

issue a regulation to address filter

backwash recycling by August 2000.

USEPA plans to develop these

regulations in conjunction with the

development of the Long-Term ESWTR.

USEPA continues to request comments

or additional information related to

recycling of filter backwash water or

filter-to-waste issues.

K. Certification Criteria for Water Plant

Operators

The July 29, 1994, notice requested

comment on whether the ESWTR

should define minimum certification

criteria for surface water treatment plant

operators. Currently, the SWTR (141.70)

requires such systems to be operated by

‘‘qualified personnel who meet the

requirements specified by the State.’’

The 1996 Amendments to the SDWA

require USEPA to undertake several

actions with regard to operator

certification, including the publication

of guidelines specifying minimum

standards.

Of the few commenters who

addressed this issue most asserted that

minimum certification criteria for water

operators should be left to the States.

One commenter contended that certified

operator(s) should be on site at all times

and that a non-certified operator should

never be in charge. Another respondent

noted that rewording § 141.70 to read

‘‘personnel who are certified by the

State, or can obtain certification within

one year of date of employment’’ will

adequately define certification criteria.

Consistent with the 1996 SDWA

amendments, USEPA appointed an

Operator Certification Working Group of

the National Drinking Water Advisory

Council (NDWAC) to form a partnership

with States, water systems and the

public to develop information on

recommended operator certification

requirements. USEPA will publish

guidelines specifying minimum

standards for certification (and

recertification) of operators of

community and nontransient

noncommunity public water systems.

USEPA is developing the draft

guidelines based on recommendations

from the NDWAC. The draft guidelines,

when available, will be published in the

Federal Register for public review and

comment. Members of the public who

are interested in further information

regarding this effort may contact

Richard Naylor of USEPA’s Office of

Ground Water and Drinking Water at

202–260–5135 or at e-mail address:

naylor.richard@epamail.epa.gov.

L. Regulatory Compliance Schedule and

Other Compliance-Related Issues

A. Regulatory Compliance Schedule

Background

During the 1992 Disinfectants/

Disinfection Byproducts Regulatory

Negotiation (reg-neg) that resulted in the

1994 proposed Stage 1 DBPR and

proposed IESWTR, there was extensive

discussion of the compliance schedule

and applicability to different groups of

systems and coordination of timing with

other regulations.

In addition to the Stage 1 DBPR, the

Negotiating Committee agreed that EPA

would (a) propose an interim ESWTR

which would apply to surface water

systems serving 10,000 or more people,

and (b) at a later date, propose a longterm ESWTR applying primarily to

small systems under 10,000. Both of

these microbial rules would be

proposed and promulgated so as to be

in effect at the same time that systems

of the respective size categories would

be required to comply with new

regulations for disinfectants and DBPs.

Finally, although the GWDR was not

specifically addressed during the regneg, EPA anticipated that it would be

promulgated at about the same time as

the IESWTR and Stage 1 DBPR.

EPA proposed a staggered compliance

schedule, based on the reg-neg results.

The Negotiating Committee and EPA

believed that such a process was needed

for the rules to be properly implemented

by both States and PWSs. Also, EPA

proposed a staggered schedule to

achieve the greatest risk reduction by

providing that larger water systems were

to come into compliance earlier than

small systems (to cover more people

earlier), and surface water systems were

to come into compliance earlier than

ground water systems (since the

potential risks of both pathogens and

DBPs were considered generally higher

for surface water systems). Large and

medium size surface water PWSs

(serving at least 10,000 people)

constitute less than 25% of community

water systems using surface water and

less than 3% of the total number of

community water systems, but serve

90% of the population using surface

water and over 60% of the population

using water from community water

systems. These large PWSs are also

those with experience in simultaneous

control of DBPs and microbial

contaminants. EPA proposed that these

systems be required to comply with the

Stage 1 DBPR and IESWTR 18 months

after promulgation of the rules and that

States would be required to adopt the

rules no later than 18 months after

promulgation. These 18 month periods

were prescribed in the 1986 SDWA

Amendments.

Surface water PWSs serving fewer

than 10,000 people were to comply with

the Stage 1 DBPR requirements 42

months after promulgation, to allow

such systems to simultaneously come

into compliance with the LTESWTR.

This compliance date reflected a

schedule that called for the LTESWTR

to be promulgated 24 months after the

IESWTR was promulgated and for PWSs

then to have 18 months to come into

compliance. Such a simultaneous

compliance schedule was intended to

provide the necessary protection from

any downside microbial risk that might

otherwise result when systems of this

size attempted to achieve compliance

with the Stage 1 DBPR.

Ground water PWSs serving at least

10,000 people would also be required to

achieve compliance with the Stage 1

DBPR 42 months after promulgation. A

number of these systems, due to

recently installing or upgrading to meet

the GWDR (which EPA planned to

promulgate at about the same time as

the Stage 1 DBPR), were expected to

need some period of monitoring for

DBPs in order to adjust their treatment

processes to also meet the Stage 1 DBPR

standards.

1996 Safe Drinking Water Act

Amendments

The SDWA 1996 Amendments

affirmed several key principles

underlying the M–DBP compliance

strategy developed by EPA and

stakeholders as part of the 1992

Regulatory Negotiation process. First,

under Section 1412(b)(5)(A), Congress

recognized the critical importance of

addressing risk/risk tradeoffs in

establishing drinking water standards

and gave EPA the authority to take such

risks into consideration in setting MCL

or treatment technique requirements.

Second, Congress explicitly adopted the

staggered M–DBP regulatory

development schedule developed by the

Negotiating Committee. Section

1412(b)(2)(C) requires that the standard

setting intervals laid out in EPA’s

proposed ICR rule be maintained even

if promulgation of one of the M–DBP

rules was delayed. As noted above, this

staggered regulatory schedule was

specifically designed as a tool to

minimize risk/risk tradeoff. A central

component of this approach was the

concept of ‘‘simultaneous compliance’’

which provides that a PWS must

comply with new microbial and DBP

requirements at the same time to assure
59518 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

that in meeting a set of new

requirements in one area, a facility does

not inadvertently increase the risk (i.e.,

the risk ‘‘tradeoff’’) in the other area.

The SDWA 1996 Amendments also

changed two statutory provisions that

elements of the 1992 Negotiated

Rulemaking Agreement were based

upon. As outlined above, the 1994 Stage

1 DBPR and ICR proposals provided that

18 months after promulgation large

PWSs would comply with the rules and

States would adopt and implement the

new requirements. Section 1412(b)(10)

of the SDWA as amended now provides

that drinking water rules shall become

effective 36 months after promulgation

(unless the Administrator determines

that an earlier time is practicable or that

additional time for capital

improvements is necessary—up to two

years). In addition, Section 1413(a)(1)

now provides that States have 24

instead of the previous 18 months to

adopt new drinking water standards that

have been promulgated by EPA.

Discussion

In light of the 1996 SDWA

amendments, developing a compliance

deadline strategy that encompasses both

the Stage 1 DBPR and IESWTR, as well

the related LTESWTR and Stage 2

DBPR, is a complex challenge. On the

one hand, such a strategy needs to

reflect new statutory provisions. On the

other, it needs to continue to embody

key reg-neg principles reflected in both

the 1994 ICR and Stage 1 DBPR

proposals; principles that both

Congressional intent and the structure

of the new Amendments, themselves,

indicate must be maintained.

An example of the complexity that

must be addressed is the relationship

between the principles of risk/risk

tradeoff, simultaneous compliance, and

the staggered regulatory schedule

adopted by Congress. Under the 1996

SDWA amendments, the staggered

regulatory deadlines under Section

1412(b)(2)(C) call for the IESWTR and

Stage 1 DBPR to be promulgated in

November 1998 and the LTESWTR in

November of 2000. However, a

complicating factor reflected in the

Negotiated Rulemaking Agreement of

1992 and contained in the 1994 ICR,

IESWTR, and Stage 1 DBPR proposals,

is that Stage 1 applies to all PWSs,

while IESWTR applies only to PWSs

over 10,000, and the LTESWTR covers

remaining surface water systems under

10,000.

One approach might be to simply

provide that each M–DBP rule becomes

effective 3 years after promulgation in

accordance with the new SDWA

provisions. For surface water systems

over 10,000, each plant would be

required to comply with related

microbial and DBP requirements at the

same time thereby minimizing potential

risk/risk tradeoffs. For surface water

systems under 10,000, however, this

approach would result in a very large

number of smaller plants complying

with DBP requirements two years before

related LTESWTR microbial provisions

became effective, thereby creating an

unbalanced risk tradeoff situation that

the Negotiating Committee, EPA, and

Congress each sought to avoid.

As this example suggests, given the

staggered regulatory development

schedule developed by stakeholders in

the reg-neg process and adopted by

Congress, there is a difficult

inconsistency between the principle of

avoiding risk tradeoffs, simultaneous

compliance, and simply requiring all

facilities to comply with applicable

M–DBP rules three years after their

respective promulgation. The challenge,

then, is to give the greatest possible

meaning to each of the new SDWA

provisions while adhering to the

fundamental principles also endorsed

by Congress of addressing risk-risk

tradeoffs and assuring simultaneous

compliance.

A further question that must be

factored into this complex matrix is how

to address the relationship between

promulgation of a particular rule, its

effective date, and its adoption by a

primacy State responsible for

implementing the Safe Drinking Water

Act. Under the 1994 IESWTR and Stage

1 DBPR proposals, the rule’s 18 month

effective date was the same as the 18

month date by which a State was

required to adopt it. This approach

reflected the 18 month SDWA deadlines

applicable during reg-neg negotiations

and at the time of proposal.

The difficulty with requiring PWS

compliance and State implementation

by the same date is that States may not

have enough lead time to adopt rules,

train their own staff, and develop

policies to implement and enforce new

rules by the deadline for PWS

compliance. In situations where the new

rules are complex and compliance

requires state review and ongoing

interaction with PWSs, successful

implementation can be very difficult,

particularly for States with many small

systems that have smaller staffs and

fewer resources to anticipate the

requirements of final rules. As noted

above, Congress addressed this issue by

extending the time for States to put their

own rules in place from 18 months to

two years after federal promulgation

and, then, by generally providing for a

one year interval before PWSs must

comply (three years after promulgation).

As a result, the 18 month interval

contemplated by the 1994 proposals is

no longer applicable, and the approach

of setting the same date for PWS

compliance and State rule

implementation is no longer consistent

with the phased approach laid out in

the new SDWA amendments.

A final set of issues that must be

addressed in connection with the Stage

1 DBPR proposal are compliance

deadlines for ground water systems that

currently disinfect. Reflecting the

Negotiated Rulemaking Agreement, the

1994 proposal provided that ground

water systems serving at least 10,000

that disinfect must comply three and

one half years (42 months) after Stage 1

DBPR promulgation. Small ground

water systems serving fewer than 10,000

that disinfect would be required to come

into compliance five years (60 months)

after Stage 1 DBPR promulgation. Again,

the challenge here is to reconcile new

statutory compliance provisions with

the principles of simultaneous

compliance, avoiding risk/risk tradeoffs,

and deference to Congress’ clear intent

to preserve the ‘‘delicate balance that

was struck by the parties in structuring

the negotiated rulemaking agreement’’.

(Joint Explanatory Statement of the

Committee on Conference on S.1316,

p2). An additional factor that must be

considered in this context is that

Congress affirmed the need for

microbial ground water regulations but

also clearly contemplated that such

standards might not be promulgated

until issuance of Stage 2 DBPR (no later

than May, 2002).

Alternative Approaches

In light of the 1996 SDWA

amendments and their conflicting

implications for different elements of

the compliance strategy agreed to by the

Negotiating Committee and set forth in

the 1994 IESWTR and Stage 1 DBPR

proposals, EPA is today requesting

comment on four alternative compliance

approaches. The Agency also requests

comment on any other compliance

approaches or modifications to these

options that commenters believe may be

appropriate.
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59519

OPTION 1.—IMPLEMENT 1994 PROPOSAL SCHEDULE

Rule

(promulgation)

Surface water PWS Ground water PWS

≥10k <10k ≥10k <10k

DBP 1 (11/98) ................................................................................................................... 5/00 5/02 5/02 11/03

IESWTR (11/98) ............................................................................................................... 5/00 NA NA NA

LTESWTR (11/00) ............................................................................................................ 1 5/02 5/02 NA NA

GWDR (11/00) .................................................................................................................. NA NA (2) (2)

1 (If required).

2 Not addressed.

Option 1 (schedule as proposed in

1994) simply continues the compliance

strategy laid out in the 1994 Stage 1

DBPR and IESWTR proposals. This

would provide that medium and large

surface water PWSs (those serving at

least 10,000 people) comply with the

final Stage 1 DBPR and IESWTR within

18 months after promulgation, and that

surface water systems serving fewer

than 10,000 comply within 42 months

of Stage 1 DBPR promulgation. This

option also would provide that ground

water systems serving at least 10,000

and that disinfect comply within 42

months, while ground water systems

serving fewer than 10,000 comply

within 60 months.

This approach was agreed to by EPA

and other stakeholder members of the

1992 Negotiating Committee. However,

it has been at least in part superseded

by both the general 36 month PWS

compliance period and the 24 month

State adoption and implementation

period provided under the 1996 SDWA

amendments. If the proposed 1994

compliance schedule were to be

retained, EPA would need to make a

determination that the statutory

compliance provision of 36 months was

not necessary for large and medium

surface systems because compliance

within 18 months is ‘‘practicable’’. To

maintain simultaneous compliance, the

Agency would also have to make the

same practicability determination for

small surface water systems in

complying with the LTESWTR and for

ground water systems serving at least

10,000 in complying with the GWDR. In

addition, the Agency would need to

justify 42 months for small surface

water systems and 60 months for small

ground water systems with disinfection

by making a national determination that

the additional time was required due to

the need for capital improvements at

each of these small systems. EPA also

would need to articulate a rationale for

why States should not be provided the

statutorily specified 24 months to

implement new complex regulatory

provisions before PWSs are required to

comply. Finally, to implement this

approach, the Agency would be

required to modify the timing associated

with the microbial backstop provision

agreed to on July 15, 1997 by the M–

DBP Advisory Committee (since a 18

month schedule would not allow time

after promulgation for medium surface

water systems (10,000–99,999) to collect

HAA data prior to having to determine

whether disinfection benchmarking is

necessary).

EPA requests comment on the issues

outlined above in connection with this

option. In particular, the Agency

requests comment and information to

support a finding that compliance by

specified systems in 18 months is

practicable for some rules, and that

extensions to 42 or 60 months for other

systems are required to allow for capital

improvements.

OPTION 2.—ADD 18 MONTHS TO 1994 PROPOSAL SCHEDULE

Rule

(promulgation)

Surface water PWS Ground water PWS

≥10k <10k ≥10k <10k

DBP 1 (11/98) ................................................................................................................... 11/01 11/03 11/03 5/05

IESWTR (11/98) ............................................................................................................... 11/01 NA NA NA

LTESWTR (11/00) ............................................................................................................ 1 11/03 11/03 NA NA

GWDR (11/00) .................................................................................................................. NA NA (2) (2)

1 (If required).

2 Not addressed.

Option 2 (each date in proposed 1994

compliance strategy extended by 18

months) reflects the fact that the 1996

SDWA amendments generally extended

the previous statutory deadlines by 18

months (to three years) and established

an overall compliance period not to

extend beyond 5 years. This second

approach would result in simultaneous

compliance for surface water systems.

Large surface water systems (those

serving at least 10,000) would have

three years to comply in accordance

with the baseline 3 year compliance

period established under Section

1412(b)(10) of the 1996 Amendments.

Small surface water systems (under

10,000) would be required to comply

with Stage 1 D/DBPR requirements

within five years and applicable

LTESWTR requirements within three

years. Since the LTESWTR will be

promulgated two years after Stage 1

DBPR (in accordance with the new

SDWA M–DBP regulatory deadlines

discussed above), the net result of this

approach is that small surface water

systems would be required to comply

with both Stage 1 DBPR and IESWTR

requirements by the same end date of

November 2003, thus assuring

simultaneous compliance. This meets

the objective of both the reg-neg process

and Congress to address risk-risk

tradeoffs in implementing new M–DBP

requirements.

USEPA believes that providing a five

year compliance period for small

surface water systems under the Stage 1

DBPR is appropriate and warranted

under section 1412(b)(10), which

expressly allows five years where

necessary for capital improvements. Of

necessity, capital improvements require
59520 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

preliminary planning and evaluation.

Such planning requires, perhaps most

importantly, identification of final

compliance objectives. This then is

followed by an evaluation of

compliance alternatives, site

assessments, consultation with

appropriate state and local authorities,

development of final engineering and

construction designs, financing, and

scheduling. In the case of the staggered

M–DBP regulatory schedule established

as part of the 1996 SDWA amendments,

LTESWTR microbial requirements for

small systems are required to be

promulgated two years after the

establishment of Stage 1 DBPR

requirements. Under these

circumstances, small systems will not

even know what their final combined

M–DBP compliance obligations are until

Federal Register publication of the final

LTESWTR. As a result, an additional

two year period reflecting the two year

Stage 1 DBPR/LTESWTR regulatory

development interval established by

Congress is required to allow for

preliminary planning and evaluation

which is an inherent component of any

capital improvement process. EPA

believes this approach is consistent with

both the objective of assuring

simultaneous compliance and not

exceeding the overall statutory

compliance period of five years. This

same logic would also apply to ground

water systems serving at least 10,000,

since such systems would need the final

GWDR to determine and implement a

compliance strategy.

With regard to extended compliance

schedules, EPA notes that the economic

analysis developed as part of the M–

DBP Advisory Committee indicates that

there will be capital costs associated

with implementation of both the

IESWTR as well as the Stage I DBP

rules. As outlined above, the 1996

SDWA amendments provide that a two

year extension may be provided by EPA

at the national level or by States on a

case-by-case basis if either EPA or a

State determines that additional time is

necessary for capital improvements.

EPA does not believe there is data

presently in the record for either of

these rulemakings to support a national

determination by the Agency that a twoyear extension is justified. EPA requests

comment on this issue and, if a

commenter believes such an extension

is warranted, requests that the

comments provide data to support such

a position.

Adding 18 months to the 1994

proposed compliance strategy would

result in 78 month (six and a half year)

compliance period for small ground

water systems. This is beyond the

overall five year compliance period

established by Congress under Section

1412(b)(10). EPA is not aware of a

rationale to support this result that is

consistent with both the objectives of

the reg-neg process and the new SDWA

amendments; however, the Agency

requests comment on this issue. As

discussed below, EPA believes there is

a reasonable compliance strategy for

addressing ground water systems that

reflects the requirements of the SDWA

amendments as well as the intent of the

reg-neg process.

OPTION 3.—REQUIRE COMPLIANCE WITH ALL RULES WITHIN THREE YEARS OF PROMULGATION

Rule

(promulgation)

Surface water PWS Ground water PWS

≥10k <10k ≥10k <10k

DBP 1 (11/98) ................................................................................................................... 11/01 11/01 11/01 11/01

IESWTR (11/98) ............................................................................................................... 11/01 NA NA NA

LTESWTR (11/00) ............................................................................................................ 1 11/03 11/03 NA NA

GWDR (11/00) .................................................................................................................. NA NA 11/03 11/03

1 (If required).

Under this approach, all systems

would be required to comply with Stage

1 DBPR, IESWTR, and LTESWTR within

three years of final promulgation. This

approach reflects the baseline three year

compliance period included as part of

the new SDWA compliance provisions.

Unlike option 2 outlined above which

simply adds an 18 month extension to

the 1994 proposed compliance

approach, this option is not tied to the

1994 proposal. Rather it applies the new

baseline three year compliance period to

the staggered M–DBP regulatory

development schedule which was also

established as part of the 1996 SDWA

amendments.

This approach would result in

simultaneous compliance for large

surface water systems. However, it

would eliminate the possibility of

simultaneous compliance for small

surface water systems and all ground

water systems. Contrary to reg-neg

objectives and Congressional intent, it

would create an incentive for risk/risk

tradeoffs on the part of small surface

water systems who would be required to

take steps to comply with Stage 1 DBPR

provisions two years before coming into

compliance with the LTESWTR, and for

all ground water systems who would be

required to take steps to comply with

Stage 1 DBPR provisions two years

before coming into compliance with the

GWDR.

OPTION 4.—MERGE SDWA PROVISIONS WITH NEGOTIATED RULEMAKING OBJECTIVES

Rule

(promulgation)

Surface water PWS Ground water PWS

≥10k <10k ≥10k <10k

DBP 1 (11/98) ................................................................................................................... 11/01 11/03 11/03 11/03

IESWTR (11/98) ............................................................................................................... 11/01 NA NA NA

LTESWTR (11/00) ............................................................................................................ 1 11/03 11/03 NA NA

GWDR (11/00) .................................................................................................................. NA NA 11/03 11/03

1 (If required).

This option combines the principle of

simultaneous compliance with the

revised compliance provisions reflected

in the 1996 SDWA amendments. Large

surface water systems would be

required to comply with Stage 1 DBPR
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59521

and IESWTR within 3 years of

promulgation, thus assuring

simultaneous compliance and

consistency with the baseline statutory

compliance period of 3 years. Small

surface water systems under 10,000

would comply with the provisions of

the Stage 1 DBPR at the same time they

are required to come into compliance

with the analogous microbial provisions

of the LTESWTR. This would result in

small surface water systems

simultaneously complying with both the

LTESWTR and Stage 1 DBPR

requirements. Under this approach,

small systems would comply with

LTESWTR requirements three years

after promulgation and Stage 1 DBPR

requirements five years after

promulgation. For the reasons

articulated under option two above,

EPA believes providing a five year

compliance period under Stage 1 DBPR

is appropriate and necessary to provide

for capital improvements.

For ground water systems, the 1994

proposed Stage 1 DBPR compliance

schedules provided for only one half of

the risk-risk tradeoff balance. They did

not include a companion rule

development and compliance schedules

for the analogous microbial provisions

of a Ground Water Disinfection Rule.

The 1996 SDWA amendments provide

an outside date for promulgation of

ground water microbial requirements of

‘‘no later than’’ May 2002, but leave to

EPA the decision of whether an earlier

promulgation is more appropriate. In

light of the reg-neg emphasis and

Congressional affirmation of the

principal of simultaneous compliance to

assure no risk-risk tradeoffs, EPA has

developed a ground water disinfection

rule promulgation schedule that will

result in a final GWDR by November

2000, the same date as the

Congressional deadline for the

LTESWTR. Ground water systems

would be required to comply with the

GWDR by November 2003, three years

after promulgation, and to assure

simultaneous compliance with DBP

provisions, such systems would be

required to comply with Stage 1 DBPR

requirements by the same date. Again,

for the reasons outlined under option 2,

USEPA believes a five year compliance

period for ground water systems is

necessary and appropriate.

Option 4 assures that ground water

systems will be required to comply with

Stage 1 DBPR provisions at the same

time that they comply with the

microbial provisions of the Ground

Water Disinfection Rule (GWDR).

Successful implementation of this

option requires that EPA develop and

promulgate the GWDR by November

2000 as indicated above. The Agency

recognizes that this is an ambitious

schedule, but believes it is necessary to

meet the twin objectives of

simultaneous implementation and

consistency with the new statutory

compliance provisions of the 1996

SDWA. In evaluating this option, the

Agency also considered the possibility

of meeting these twin objectives in a

somewhat different fashion by delaying

final promulgation of the Stage I DBP

rule as it applies ground water systems

until the promulgation of the GWDR.

This alternative possibility would

assure simultaneous compliance and

also provide a ‘‘safety net’’ in the event

that the GWDR November 2000

promulgation schedule is delayed. EPA

is concerned, however, that this

approach may not meet or be consistent

with new SDWA requirements which

provide that the Stage I DBPR be

promulgated by November 1998. The

Agency requests comment on this issue.

Recommendation

EPA has evaluated each of the

considerations identified in Options 1

through 4. On balance, the Agency

believes that Option 4 is the preferred

option. The primary reasons are (1) to

allow States at least two years to adopt

and implement M–DBP rules consistent

with new two year time frame provided

for under the 1996 SDWA amendments,

(2) to match the compliance schedules

for the LTESWTR and Stage 1 DBPR for

small (<10,000 served) surface water

systems to allow time for capital

improvements and addressing risk-risk

tradeoff issues, and (3) to assure that all

ground water systems simultaneously

comply with newly applicable microbial

and Stage 1 DBPR requirements on the

same compliance schedule provided for

small surface water systems.

Request for Comments

EPA requests comment on both the

compliance schedule options discussed

above and on any other variations or

combinations of these options. EPA also

requests comment on its preferred

option 4 and on the underlying rationale

for allowing a five year compliance

schedule for ground water and small

surface water systems under the Stage 1

DBPR.

B. Compliance Violations and State

Primacy Obligations

A public water system that fails to

comply with any applicable

requirement of the SDWA (as defined in

1414 (I)) is subject to an enforcement

action and a requirement for public

notice under the provisions of section

1414. Applicable requirements include,

but are not limited to, MCLs, treatment

techniques, monitoring and reporting.

These regulatory requirements are set

out in 40 CFR l41.

The SDWA also requires States that

would have primary enforcement

responsibility for the drinking water

regulations (‘‘primacy’’) to adopt

regulations that are no less stringent

than those promulgated by EPA. States

must also adopt and implement

adequate procedures for the

enforcement of such regulations, and

keep records and make reports with

respect to these activities in accordance

with EPA regulations. 5 U.S.C. 1413.

EPA may promulgate regulations that

require States to submit reports on how

they intend to comply with certain

requirements (e.g., how the State plans

to schedule and conduct sanitary

surveys required by the IESWTR), how

the State plans to make certain

decisions or approve PWS-planned

actions (e.g., approve significant

changes in disinfection under the

IESWTR or approve Step 2 DBP

precursor removals under the enhanced

coagulation requirements of the Stage I

DBPR), and how the State will enforce

its authorities (e.g., correct deficiencies

identified by the State during a sanitary

survey within a specified time). The

primacy regulations are set out in 40

CFR 142.

EPA drafted requirements for both the

PWSs (part 141) and the primacy States

(part 142) in the proposed rules. EPA is

requesting comments on whether there

are elements of the Advisory

Committee’s recommendations in this

Notice that should be treated as

applicable requirements for the PWS

and included in part l41 as enforceable

requirements. Similarly, EPA requests

comments on whether there are

elements of the Advisory Committee’s

recommendations in this Notice that

should be treated as requirements for

States and included in part 142 as

primacy requirements.

C. Compliance With Current Regulations

EPA reaffirms its commitment to the

current Safe Drinking Water Act

regulations, including those related to

microbial pathogen control and

disinfection. Each public water system

must continue to comply with the

current rules while new microbial and

disinfectants/disinfection byproducts

rules are being developed.

M. Disinfection Studies

1. New Giardia Inactivation Studies at

High pH Levels

The Surface Water Treatment Rule

(SWTR) requires plants treating surface
59522 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

water to meet minimum inactivation/

removal requirements for Giardia cysts

and viruses. Under the SWTR, the

concept of CT values (disinfectant

residual concentration (C ) multiplied

by contact time (T)) is used for

estimating inactivation efficiency of

disinfection practices in plants. As a

supplement to the rule, USEPA

published a guidance manual document

entitled ‘‘Guidance Manual for

Compliance with the Filtration and

Disinfection Requirements for Public

Water Systems Using Surface Water

Sources’’ (USEPA 1991a) [SWTR

Guidance Manual]. In this manual, CT

tables (Log inactivation versus CT

values under different environmental

conditions) are provided to utilities as a

guidance in carrying out the

disinfection requirements.

The SWTR Guidance Manual did not

include CT values at pH values above 9

due to the limited research results

available at the time of rule

promulgation. pH values above 9 mainly

exist in plants with lime softening

processes. An approach for extending

the existing CT tables in the SWTR

Guidance Manual to the upper pH

boundary (pH 11.5) that may occur in

some plants is presented below. With

this approach, the latest available data

reported by Logsdon et al. (1994) was

used as a basis for CT values at high pH

values by applying a linear regression to

Logsdon’s experimental results in

laboratory water and a safety factor to

cover the variability in natural water.

Analysis of Logsdon’s Data: Logsdon

et al. (1994) performed Giardia

inactivation experiments with free

chlorine in both laboratory and natural

waters at 5°C and at pH values of 9.5,

10.5, and 11.5. The analysis of MW-s’s

data is performed with the following

assumptions:

1. Since the experimental data of MWs et al. for CT values vs. log inactivation

are relatively scattered, a sophisticated

model will not improve the result of

simulation. Rather, a linear regression

was used to fit these data points, by

assuming the dilution coefficient n=1 in

the conventional Watson’s Law (firstorder kinetics).

2. Data points for inactivation greater

than 3-logs in the Logsdon et al. report

are not included in the linear regression

because of their uncertainty.

3. Data points for natural water have

a greater variability than those for

laboratory water. Also, CT tables in the

SWTR Guidance Manual were

developed solely based on tests using

laboratory water. To ensure consistency,

therefore, data points for natural water

from the Logsdon et al. study were not

used. However, a safety factor was

applied to the CT values estimated from

laboratory data to reflect the variability

of inactivation results in natural water.

4. To be consistent, the safety factor

of CT values at pH > 9 is assumed to be

the same as that for the existing CT

values in the SWTR Guidance Manual at

pH ≤ 9. To appropriately quantify a

safety factor being applied to obtain

those existing CT values in the SWTR

Guidance Manual, the previous data

base for pH ≤ 9 was reevaluated and

interpreted in the same manner as that

for pH > 9 (using a linear regression and

a safety factor). Subsequently, the safety

factor was set at a value such that, if

multiplied by the CT values estimated

by a linear regression, the resultant CT

values would match the existing CT

values in the SWTR Guidance Manual.

5. For determination of a safety factor,

data from the following studies were

considered: Jarroll et al. (1981), Rice et

al. (1982), Hibler et al. (1987), and

Rubin et al. (1989) [Those data were

used as a basis for developing the

existing CT values in the SWTR

Guidance Manual.]. Only the data from

Jarroll et al. (1981) were used in the

linear regression because the protocols

or conditions in other studies are not

comparable to those used in the study

by Logsdon et al. (1994), as noted below:

(1) The study by Hibler et al. (1987) was

based on animal infectivity tests. Excystation

was used in the study by Logsdon et al.

(1994).

(2) The study by Rubin et al. (1989) was

conducted only at 15°C while the study by

Logsdon et al. (1994) was performed at 5°C.

(3) No data for control excystation was

shown in the study by Rice et al. (1982) and

therefore this data was not used in the

regression analysis.

The data from Jarroll et al. (1981) for

chlorine concentrations of 4 and 8 mg/

L were not used in the regression

analysis because the chlorine residual in

the study by Logsdon et al. (1994) was

no higher than 2.1 mg/L.

The Results of Data Analysis: The

data from Jarroll et al. (1981) pertaining

to log inactivation versus CT values are

plotted in Figures 8—10 for pH values

of 6, 7, and 8, respectively. Because

Jarroll et al. found that essentially no

inactivation at pH values of 6–8 was

observed in control samples in which

no disinfectant was added within 60

minutes (i.e., CT = 0, log inactivation =

0), the intercept of the linear regression

line was zero.

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BILLING CODE 6560–50–C

The regression results with the values

of the Watson coefficient k are shown in

each figure. Based on these results, CT

values for a designated log inactivation

at the three different pH values are

estimated and shown in Table 6. By

trials, it is found that if a safety factor

of 1.5 is applied to those estimated CT

values, the resulting CT values

approximate the values in the SWTR

Guidance Manual for chlorine

concentration ≤ 2 mg/L: at pH 6, the

safety-factored CT values are slightly

higher than those in the SWTR

Guidance Manual; at pH 7, the safetyfactored CT values are about in the

middle of the range of CT values in the

SWTR Guidance Manual; at pH 8, the

safety-factored CT values are in the low

range of CT values in the SWTR

Guidance Manual. Therefore, a safety

factor of 1.5 appears appropriate for the

development of CT tables at higher pHs.

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The Logsdon data for Giardia

inactivation with chlorine are shown in

Figures 11–13 for pH values of 9.5, 10.5,

and 11.5, respectively. Since Logsdon et

al. (1994) also observed that little or no

inactivation was caused by a high pH

itself (i.e., non-disinfected lime softened

water) in at least 6 hours, the intercept

of the linear regression line should be

zero. Based on the determinant k values

indicated in each Figure, CT values

required for inactivation in the range of

0.5–3 log at pH values of 9.5–11.5 and

temperature of 5°C are estimated and

tabulated in Table 7. To evaluate the

adequacy of the safety factor value (1.5),

the line of log inactivation versus the

safety-factored CT values is also shown

in each of Figures 11–13. It can be seen

from Figures 11 and 12 that most data

points for natural water are above the

safety-factored line, and few points are

near the line, indicating the safety factor

of 1.5 is appropriate for the

establishment of CT tables for pH > 9.

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TABLE 7.—ESTIMATED CT VALUES

FOR pH=9.5–11.5 AT C ≤ 2 mg/L

AND AT 5°C—BASED ON THE

LOGSDON’S STUDY FOR LABORATORY WATER

pH Log inactivation

Estimated

CT mgmin/L

Estimated

CT × 1.5

S.F.

pH=9.5 ... 0.5 21 32

1 42 63

1.5 62 93

2 83 124

2.5 104 156

3 125 188

pH=10.5 0.5 70 105

1 141 212

1.5 211 316

2 282 423

TABLE 7.—ESTIMATED CT VALUES

FOR pH=9.5–11.5 AT C ≤ 2 mg/L

AND AT 5°C—BASED ON THE

LOGSDON’S STUDY FOR LABORATORY WATER—Continued

pH Log inactivation

Estimated

CT mgmin/L

Estimated

CT × 1.5

S.F.

2.5 352 528

3 422 633

pH=11.5 0.5 128 192

1 256 384

1.5 385 578

2 513 770

2.5 641 962

3 769 1154

By comparing the data in Table 6 and

10, it is seen that estimated CT values

at pH 9.5 are consistently lower than

those at pH 8 in the SWTR Guidance

Manual. To maintain the consistency of

an increasing trend of CT values with an

increasing pH and be conservative for

compliance purposes, the mathematical

model described in the SWTR Guidance

Manual (equation 15 in Appendix F) by

Clark and Regli (1993) is used to extend

the existing CT tables in the SWTR

Guidance Manual to pH=9.5, e.g.,

CT=60 mg/L for 0.5 log inactivation

with 1 mg/L of chlorine at 5°C. As

proposed in the SWTR Guidance

Manual, the equation can be directly

applied to estimate CT values for 0.5

and 5°C, and a twofold decrease in CT

values for every 10°C increase in

temperature can be assumed when it is

higher than 5°C. Consequently, the CT
59530 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

values for Giardia inactivation with free

chlorine at pH 9.5 are computed and

shown in Table 8.

The same temperature correction

factor above is used to estimate CT

values for pH values of 10.5 and 11.5 at

temperature from 5 to 25°C, and 1.5 of

temperature factor is applied to convert

CT values at 5°C to those at 0.5°C.

Subsequently, the safety-factored CT

values for Giardia inactivation with free

chlorine were estimated and

summarized in Tables 11 and 13 for pH

values of 10.5 and 11.5, respectively. It

should be mentioned that although the

level of chlorine residual (the C value)

may affect CT values shown in Tables

12 and 13, it is recommended that those

values are only applicable to a C value

up to 3 mg/L, at least until more

research data become available.

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BILLING CODE 6560–50–C

In summary, the CT table for Giardia

inactivation with free chlorine at pH 9.5

was developed by using the same

approach in the SWTR Guidance

Manual for the existing CT tables at

lower pH values. For the development

of CT tables at pH values of 10.5 and

11.5, the data reported by Logsdon et al.

(1994) was used with a linear regression

multiplied by a safety factor of 1.5. The

new CT values are shown in Tables 11,

12, and 13 for pH values of 9.5, 10.5,

and 11.5, respectively. USEPA solicits

comment on the approach taken and

whether the CT values shown in Tables

11, 12 and 13 are appropriate for

revising existing guidance for estimating

inactivation efficiencies for chlorine at

pHs above 9. USEPA also solicits

comment on other approaches for

developing criteria by which systems

could estimate inactivation efficiencies

at pHs above 9.

2. Effectiveness of Different

Disinfectants on Cryptosporidium

When the ESWTR was proposed in

1994, USEPA recognized that chlorine

disinfectants were relatively ineffective

in inactivating Cryptosporidium, but

was not certain if alternative

disinfectants might be more effective

than chlorine. No public comment

addressed this issue directly. Studies

since the proposal have confirmed the

ineffectiveness of chlorine species, such

as free chlorine and monochloramine,

for the practical inactivation of

Cryptosporidium. However, new data

suggest that sequential disinfection with

free chlorine followed by

monochloramine can achieve a greater

degree of Cryptosporidium inactivation

than by chlorine alone. Moreover, ozone

and chlorine dioxide have been found to

be much more effective than chlorine.

Sequential disinfection such as ozone or

chlorine dioxide followed by one of the

chlorine species appears more powerful

than either disinfectant alone in

inactivating Cryptosporidium. The

following data detail the inactivation of

Cryptosporidium by individual

disinfectants, as well as by sequential

disinfectants.

The purpose of presenting this data in

this section is to provide the public

opportunity to comment on whether

there is (a) sufficient information

available for generating CT tables to

estimate log inactivation of

Cryptosporidium, comparable to what

was done for Giardia under the SWTR,

and (b) sufficient data to conclude that

chlorination, at levels commonly

practiced by utilities, is virtually

ineffective for inactivating

Cryptosporidium. Both of these issues

relate to USEPA’s rationale for using

Giardia as the key target organism for

defining the disinfection benchmark

(see Section D).

Table 11a summarizes the data on

disinfection of Cryptosporidium with
59534 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

chlorine species and ultraviolet

radiation (UV). The results from studies

with free chlorine indicate that some

inactivation of C. parvum could be

achieved at relatively high doses of

chlorine (i.e., >1,000 mg/L of chlorine

bleach and 80 mg/L of free chlorine)

(Korich et al., 1990a; Ransome et al.,

1993) and a high CT value (7,200 mgmin/L) (Korich et al., 1990a; Lykins et

al., 1992). However, this common water

disinfectant has been conclusively

shown to be ineffective for inactivation

of C. parvum oocysts at practical plant

doses (<6 mg Cl2/L) or CT values

(Korich et al., 1990a; Ransome et al.,

1993; Finch et al., 1997). The same is

essentially true for monochloramine

(Lykins et al., 1992; Finch et al., 1997)

and the oxidant of permanganate (Finch

et al., 1997). Therefore, it is unlikely

that significant inactivation of

Cryptosporidium will occur in water

treatment plants with the single

addition of these disinfectants at

currently used levels.

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As indicated in Table 11a, the

literature data on Cryptosporidium

inactivation with UV appear

controversial because of different

experimental protocols used by different

investigators. Finch et al. (1997) found

that UV was ineffective in inactivating

C. parvum suspended in a batch reactor.

However, significant inactivation was

observed when the oocysts were

captured in 2cm filters and exposed to

a preset UV irradiation dose (Campbell

et al., 1995; Clancy et al., 1997). More

data are needed to evaluate the practical

application of UV for inactivation of

Cryptosporidium oocysts. Also, of

interest are possible synergistic effects

with UV application followed by

residual disinfectants.

Table 11b summarizes the findings of

inactivation of Cryptosporidium with

ozone. The data obtained from benchscale tests with oxidant-demand-free

laboratory water indicate that for CT

values between 1.2–23.0 mg-min/L, the

range of inactivation was 0.5 to 5 log at

temperatures of 5 to 25 °C and at pH

values of 7 to 8 (Peeters et al., 1989;

Korich et al., 1990a,b; Parker et al.,

1993; Ransome et al., 1993; Finch et al.,

1994 & 1997). The variability

demonstrated in these results is

influenced by the differences in test

procedures used by different

researchers, i.e., the different measures

of Cryptosporidium inactivation

(infectivity, excystation, etc.) and the

different methods of CT calculations

(initial ozone dose, average ozone

concentration, and ozone residual).

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Therefore, caution should be used

when comparing the results from one

study to another. For instance, a CT

value of 10 mg-min/L for 0.5-log

inactivation was obtained from the

study conducted by Parker et al. (1993),

who used vital dyes to evaluate the

viability of Cryptosporidium. This result

is incomparable to the data shown in

Table 11b. Subsequently, Korich et al.

(1993) found that vital stains are of

questionable value for determining

oocyst viability.

In another example, in a series of

experiments at pH 7 and at temperatures

of 5–22 °C, Finch et al. (1997) found a

45–92% reduction in ozone

concentration at initial residuals of 0.6–

2.2 mg/L and contact times of 5–15

minutes. Parker et al. (1993) reported

that the Cryptosporidium inactivation

level was greater when the ozone

concentration was maintained at a

constant level (i.e., through a batch

mode reactor), compared to when the

same initial ozone dose was allowed to

decay during the same contact time.

Both Finch et al. (1994) and Parker et al.

(1993) found that an increase in

temperature caused a higher

inactivation at the same ozone residual

and the same contact time. It appears

that an increase of 15 °C decreases by

half the CT values needed for a 2-log

inactivation.

Owens et al. (1994) observed that C.

muris is slightly more resistant to ozone

than C. parvum, and proposed that C.

muris be used as a surrogate model for

C. parvum. However, the data that

support this hypothesis are very limited.

Two pilot-scale studies with natural

waters have been performed (Danial et

al., 1993; Miltner et al., 1997). The CT

values of ozone required to achieve 2-

and 3-logs inactivation of

Cryptosporidium were 6.0 mg-min/L

(pH 8, 24 °C) (Miltner et al., 1997) and

10–15 mg-min/L (pH 7, 15 °C) (Danial

et al., 1993). It appears that higher CT

values are required in natural water for

inactivation of Cryptosporidium than in

laboratory water; this may be attributed

to the existing oxidant demands in

natural water or other factors. Danial et

al. (1993) indicated that the ozone

residual for a given dose rapidly

decomposed as the pH was increased

from 7 to 9 during lime addition. This

finding implies that if ozonation is

practiced in lime-softening water plants,

it will be necessary to adjust the pH

downstream.

When inactivation of

Cryptosporidium oocysts is compared

with that of Giardia cysts with similar

test protocols, C. parvum is

approximately 10 times more resistant

to ozone than G. lamblia in laboratory

water (Finch et al., 1994) and G. muris

in natural water (Owens et al., 1994;

Miltner et al., 1997). These findings

imply that the use of ozone cannot be

expected to significantly inactivate

Cryptosporidium at the concentration

and contact times employed in

inactivating Giardia in water treatment

practices.

Table 11c summarizes the findings of

Cryptosporidium inactivation with

chlorine dioxide. For CT values between

23–213 mg-min/L, the range of

inactivation is 0.5–3.2 log or higher at

temperatures of 10–25 °C and at pH

values of 7–8 in laboratory water

(Peeters et al., 1989; Korich et al., 1990b;

Ransome et al., 1993; Finch et al., 1995

& 1997). Similar to ozone, chlorine

dioxide is also unstable in the water. In

0.05 M phosphate buffer water at pH 8

and 22 °C, Finch et al. (1997) found that

a 49–99% reduction in chlorine dioxide

concentrations occurs after 15–120

minutes at initial residuals of 0.36–3.3

mg/L. LeChevallier et al. (1997b)

recently performed a pilot-scale study in

a natural water by evaluating viability of

oocysts with both an in-vitro

excystation assay and a tissue culture

infectivity. While the difference in

results with the two methods was not

shown, the study reported that a CT

value of 40 mg-min/L results in 1-log

inactivation of oocysts at pH 8.0 and

20°C, and a 0.5-log inactivation at pH

6.0. The study also revealed that a

temperature reduction from 20 to 10 °C

decreases the effectiveness of chlorine

dioxide by 40%.

The existing data show chlorine

dioxide as an effective disinfectant for

Cryptosporidium inactivation. However,

CT values required for Cryptosporidium

inactivation appear much higher than

those for same log inactivation of

Giardia under comparable water

conditions (Lisle and Rose, 1995). Since

the 1994 D/DBP proposed rule has set

the maximum contaminant levels for

chlorine dioxide and chlorite (byproduct of chlorine dioxide), at 0.8

mg/L and 1 mg/L, respectively, the use

of chlorine dioxide may be limited for

the inactivation of Cryptosporidium.

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Table 12 summarizes the results from

Finch et al. (1997). Finch et al. found

that sequential disinfection of C.

parvum oocysts by different

disinfectants is more effective than that

indicated by the effectiveness of each

disinfectant from independent studies,

i.e., the effect is synergistic. According

to their current report, greater than 2.9-

log inactivation of oocysts can be

achieved when C. parvum is exposed to

0.75 mg/L initial ozone residual for 3.7

minutes and then 2.0 mg/L free chlorine

residual for 265 minutes (pH 6). Based

on the additive effects of ozone and free

chlorine alone under similar conditions,

a 2.0-logs inactivation is expected.

Similarly, the inactivation by

monochloramine following ozonation is

increased by 1.5 log-units when

compared with either ozone or

monochloramine alone.

Additional 1.2-log inactivation due to

the synergism of chlorine dioxide and

free chlorine has also been obtained at

pH 8. Furthermore, sequential exposure

of C. parvum oocysts to free chlorine

followed by a monochloramine (pH 8.0)

reduces infectivity by 0.6 log. Since the

expected inactivation by either chlorine

species at pH 8 is virtually zero, there

is a synergism between free chlorine

and monochloramine. It should be

noted that combinations of chlorine

species with other disinfectants may

stimulate the formation of chlorate

(Siddiqui et al., 1996) or other toxic

disinfectant byproducts. Also, the

synergistic effect with sequential

disinfectants has only been observed in

bench-scale studies in a single

laboratory. Nevertheless, such findings

suggest new strategies for the effective

inactivation of Cryptosporidium. For a

practical application, further

investigations are being conducted at a

wider range of water quality conditions

(pH, temperature, and disinfectant

demand) (USEPA, 1995b).

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Analytical Method—Four analytical

methods are currently being used to

evaluate inactivation of

Cryptosporidium oocysts: in vitro

excystation, vital dyes (DAPI/PI

staining), animal infectivity, and tissue

culture infectivity. It has been shown

that excystation and DAPI/PI staining

consistently underestimate inactivation

when compared with animal infectivity,

which is more expensive (Finch et al.,

1994; Black et al., 1996). The use of

different animal models also leads to

inconsistent results for Cryptosporidium

infectivity. Although the tissue culture

technique may provide a convenient,

low-cost alternative to animal

infectivity, only limited data exist with

this method (LeChevallier et al., 1997b).

Cryptosporidium Inactivation Map—

In conjunction with development of the

long-term ESWTR, USEPA is developing

a graph of CT values versus log

inactivation under various water quality

conditions. The Agency is also

exploring other means that utilities can

use to estimate Cryptosporidium

inactivation with different single or

sequential disinfectants. Additional

data, especially under natural water/

field conditions, is necessary to develop

this graph. Finch et al. (1994) attempted

to establish CT tables for

Cryptosporidium inactivation with

ozone by analyzing numerous sets of

experimental data by using both the

Chick-Watson model and the Hom

model. It was found that the

inactivation kinetics of C. parvum by

ozone deviated from the simple firstorder Chick-Watson model and was

better described by a nonlinear Hom

model. A further analysis, however,

hasn’t been performed on a broader data

basis to evaluate such a finding.

Moreover, a much better understanding

of Cryptosporidium inactivation with

sequential disinfectants is needed.

3. New Virus Inactivation Studies

One of the treatment options that

USEPA proposed as part of the ESWTR

was to include a 4-logs minimal

inactivation requirement for viruses, in

addition to any physical removal of

viruses that might be achieved. USEPA

intends to consider this option when

additional data become available.

However, significant data are available

regarding disinfection conditions

necessary to achieve different

inactivation levels of viruses. The

availability of such data is discussed

below.

USEPA’s guidance manual to the

SWTR (USEPA, 1991a), assumes that CT

values for chlorine necessary to achieve

a 0.5-log inactivation of Giardia cysts

will result in greater than a 4-log

inactivation of viruses. This assumption

is based on the comparison between the

effects of free chlorine on Giardia

lamblia and hepatitis A virus (HAV). In

the proposed ESWTR, USEPA noted

that some viruses are more resistant to

chlorine than is HAV, and the use of

disinfectants other than free chlorine to

achieve 0.5-log inactivation of Giardia

may not yield a 4-log inactivation of

viruses. Achieving adequate

inactivation of viruses may be of greater

concern when disinfectants other than

chlorine (e.g., chlorine dioxide and

ozone) are used to inactivate

Cryptosporidium oocysts.

CT tables in the SWTR for estimating

viral inactivation efficiency with

chlorine dioxide and ozone were based

on laboratory studies using HAV and

poliovirus 1, respectively. Very few

studies have since been conducted to

investigate viral inactivation with

chlorine dioxide. Huang et al. (1997)

evaluated the disinfection effects of

chlorine dioxide on six viruses,

including poliovirus type 1,

coxsackievirus type B3, echovirus 11,

adenovirus type 7, herpes simplex virus

1, and mumps virus. All viruses were

completely inactivated at CT=90 mgmin/L (3 mg/L of initial dose and 30

minutes of contact time) at pH values of

3, 5, and 7, but not 9. Complete

inactivation of all six viruses was also

found at CT=30 mg-min/L (1 mg/L of

initial dose and 30 minutes of contact

time) at pH 7.0. At 7.0 mg/L of initial

dose, greater than 10 minutes of contact

time were required for complete

inactivation at the same pH.

More studies have been performed to

evaluate viral inactivation efficiencies

by ozone than by chlorine dioxide. The

results from these studies are

summarized in Table 13.

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In general, the tested viruses,

including HAV, MS2 coliphage,

poliovirus 1 (PV1), poliovirus 3 (PV3),

and T2 phage, are relatively sensitive to

ozone, and more than 4-logs

inactivation of these viruses can be

achieved with less than 2 mg/L of ozone

and 5 minutes of contact time in a wide

range of pH values and temperatures

(Herbold et al., 1989; Kaneko, 1989;

Vaughn et al., 1990; Finch et al., 1992;

Hall and Sobsey, 1993; Miltner et al.,

1997). Finch et al. (1992) reported that

MS2 coliphage was extremely sensitive

to ozone in both laboratory water and

natural water, and that complete viral

inactivation could occur during the

process of satisfying ozone demand in

natural water. In paired experiments,

they also found that there was

significantly less inactivation of PV3

than MS2 coliphage under the same

ozonation conditions. In contrast, Hall

and Sobsey (1993) demonstrated that

MS2 coliphage was at least as resistant

to ozone as HAV in a pH range of 6–10,

suggesting that MS2 coliphage might be

a good model for predicting HAV

inactivation by ozone. In a continuousflow system with a constant flow of

ozone and viral suspensions, Herbold et

al. (1993) found that HAV required

approximately three times the ozone

that PV1 required for the same

inactivation. In a similar system,

Botzenhart et al. (1993) showed that

MS2 coliphage was more resistant to

ozone than PhiX 174 coliphage.

Some researchers have pointed out

that viral disinfection with ozone is

difficult to evaluate, not only due to the

relatively short inactivation times, but

also because the concentration of ozone

significantly decreases during the

contact time. Finch et al. (1992) found

ozone dose and the interaction between

ozone dose and dissolved organic

carbon (DOC) were the most important

factors affecting ozone inactivation of

MS2 coliphage in surface waters.

Inactivation of MS2 coliphage was

significantly reduced when the natural

DOC in the water increased during

spring runoff, presumably because the

ozone concentration was rapidly

depleted by the DOC. This effect,

however, was not observed when an

ozone residual of 0.1 mg/L at the end of

30 seconds was detected, resulting in

greater than 4-logs inactivation of MS2

coliphage under all water quality

conditions.

Finch et al. (1992) found that the

effects of temperature and turbidity on

inactivation rates were

indistinguishable from experimental

error. This contrasts with other studies

that reported that viral inactivation with

ozone was more efficient at lower

temperatures (Botzenhart et al., 1993;

Herbold et al., 1993), and the presence

of kaolin particles at 1 mg/L or higher

resulted in a greater level of ozone

residual required for the same level of

viral inactivation (Kaneko, 1989).

Vaughn et al. (1990) observed that the

pH-related effects on ozonation of

viruses was not significant in a pH range

of 6–8. Kaneko (1989) reported that the

presence of ammonium decreased the

ozone concentration and thus decreased

the inactivation efficiency of ozone.

Kaneko (1989) also revealed that

ozonation of viruses could be divided

into three phases: an initial large

reduction of viruses; a subsequent

logarithmic reduction of viruses; and

finally, a slow reduction in response to

decreasing ozone concentrations. Thus,

it is not surprising that the viral

inactivation rate beginning 5 minutes

after adding the disinfectant was greater

with chlorine than with ozone, even

though the inactivation rates within 5

minutes of the addition of ozone were

10 to 1,000 higher than the initial rates

of inactivation with chlorine (Kaneko

and Igarashi, 1983; Kaneko, 1989).

Finch et al. (1992) have concluded

that, when comparing the ozone

inactivation data for MS2 coliphage,

PV3, and Giardia muris, the conditions

for inactivating G. muris cysts are the

most rigorous and it is likely that enteric

viruses will be inactivated by greater

than 4 logs when Giardia is inactivated

by 3 logs. Such a comparison is also

needed for chlorine dioxide. Although

the tested enteric viruses appear to be

more susceptible to ozone than Giardia,

no data are yet available on the

effectiveness of ozone in inactivating

Norwalk virus and other pathogenic

human viruses, especially when they

are clumped and adsorbed to organic

matter as they usually are in natural

water. The varying results on viral

inactivation with ozone suggest that

ozone inactivation studies need to

measure and report ozone

concentrations over time.

III. Economic Analysis of the M–DBP

Advisory Committee Recommendations

A. Overview of RIA for Proposed Rule

The Regulatory Impact Analysis (RIA)

for the proposed IESWTR (59 FR 38832,

July 29, 1994), estimated national

capital and annualized costs (amortized

capital and annual operating costs) for

surface water systems serving at least

10,000 people at $3.6 billion and $391

million respectively. These costs were

based on the assumption that systems

would also be required to provide

enough treatment to achieve less than a

10¥4 risk level from giardiasis while

meeting the Stage 1 DBPR. In estimating

these costs, it was assumed that

additional Giardia reduction beyond the

requirements of the SWTR to achieve

the 10¥4 risk level would be achieved

solely by using chlorine as the

disinfectant and providing additional

contact time by increasing the

disinfectant contact basin size.

The Regulatory Impact Analysis for

the Interim Enhanced Surface Water

Treatment Rule (USEPA, 1994d)

predicted that ESWTR compliance

would result in no more than a few

hundred infections caused by

waterborne Giardia per year per 100

million people. This is hundreds of

thousands of cases fewer than predicted

in the absence of an ESWTR. USEPA

estimated that the benefit per Giardia

infection avoided would be $3000 per

case. Using this estimate, the 400,000 to

500,000 Giardia infections per year that

could be avoided would have an

economic value of $1.2 to $1.5 billion

per year. This suggests that the benefit

nationwide of avoiding Giardia

infections is as much as three or four

times greater than the estimated $391

million national annual cost of

providing additional contact time.

Table 14 shows this $391 million

estimated cost as described in the

proposal (using 1992 $s and a discount

rate of 10 percent). The table also

converts this cost to 1997$s (with a 10

percent discount rate) to provide for

comparison with costs based on

provisions included in this notice.

For a more detailed discussion of the

cost and benefit analysis of the 1994

proposal refer to The Regulatory Impact

Analysis for the Interim Enhanced

Surface Water Treatment Rule (USEPA,

1994d).

B. What’s Changed Since the Proposed

Rule

The cost estimates in the proposed

rule reflect cost estimates for one of

several regulatory alternatives included

in the proposal. At the time of proposal

USEPA assumed that additional data

would be collected under the ICR to

more accurately estimate costs and

benefits of the Giardia based rule option

as well as alternative regulatory options.

National source water occurrence data

for Giardia and Cryptosporidium are

being collected as part of the ICR to help

this effort. Due to the delays discussed

earlier in this Notice and the new

expedited rule deadlines, ICR data will

not be available for the IESWTR impact

analysis. From February 1997, however,

the Agency has worked with

stakeholders to identify additional data

available since 1994 to be used in

developing components of the
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expedited rules. USEPA established the

Microbial and Disinfectants/

Disinfection Byproducts Advisory

Committee to collect, share and analyze

new information and data, as well as to

build consensus on the regulatory

implications of this new information.

The Committee met five times from

March to July, 1997 to discuss issues

related to the IESWTR and Stage I D/

DBPR.

USEPA has also evaluated comments

received on the proposal in its

consideration of elements to be

included in a regulatory option

independent of ICR source water

occurrence data. These comments

suggested (1) sufficient degrees of

effectiveness of current treatment,

including filtration, in preventing

waterborne transmission of

Cryptosporidium and (2) a revised

approach focussing on optimizing

treatment processes. In response to

these comments, new information

received and the Advisory Committee’s

recommendations, USEPA has

developed the Economic Analysis

described in summary below. Details of

the analysis used to derive the costs and

benefits described below are available in

the draft document Economic Analysis

of M/DBP Advisory Committee

Recommendations for the Interim

Enhanced Surface Water Treatment Rule

(USEPA, 1997a). The economic analyses

are based on the Committee’s

recommendations to USEPA on issues

including turbidity control, removal of

Cryptosporidium, disinfection

benchmarking and sanitary surveys.

C. Summary of Cost Analysis

1. Total National Costs

USEPA is considering several

approaches, based on the

recommendations of the Advisory

Committee. The two most substantial

approaches, from the perspective of

costs and benefits, govern turbidity

performance and turbidity monitoring.

The Microbial and Disinfectants/

Disinfection Byproducts Committee

made a number of recommendations

that are indicated in this Notice for

comment, including new turbidity

provisions with associated monitoring

requirements, disinfection

benchmarking practices to help ensure

there are no significant increases in

microbial risk while systems comply

with the Stage 1 DBPR and a sanitary

survey provision of relatively minimal

costs. USEPA estimates that the national

capital and annualized costs (amortized

capital and annual operating costs) of

these provisions (based on a 10 percent

interest rate) would be $730 million and

$312 million, respectively [Table 14]

(USEPA, 1997a). These figures include

costs associated with improved

treatment, turbidity monitoring, a

disinfection benchmark and sanitary

surveys. This represents a reduction of

over $3.4 billion (in 1997 $s) from the

capital costs estimated for the proposed

rule. This is accounted for primarily by

the recommendations for changes in the

level of disinfection required and

restoration of disinfection credit prior to

precursor removal. This would result in

fewer systems needing to install

additional disinfectant contact basins,

relative to the costs in the 1994

proposal.

A discount rate of 10 percent was

used to calculate the unit costs for the

national cost model. This discount rate

provides both a link to the 1994

IESWTR cost analyses and is a

reasonable estimation of the cost to

utilities to finance capital purchases

assumed to be necessary due to the

proposal.

In order to demonstrate the sensitivity

of the national cost model to different

discount rates, the national costs at 10

percent are compared to national costs

calculated using a 7% discount rate.

This rate represents the standard social

discount rate preferred by the Office of

Management and Budget for benefit-cost

analyses of government programs and

regulations. Tables of unit cost estimates

at the 7 percent rate are included in the

appendix to the draft Economic

Analysis and displayed for comparative

purposes (USEPA, 1997a). Costs

presented in the Economic Analysis are

expressed in June 1997 constant dollars.

The water flow rates that were used

in calculating the costs of the 1994

proposal (in 1992 $s and 1997 $s) were

also used in calculating the national

costs of the recommended provisions

discussed in this Notice. Additional

analyses gauged the sensitivity of the

cost model to a different input value for

maximum flow rates for the largest

system category (systems serving >1

million people). With this adjusted flow

rate (using a 10 percent discount rate)

total annualized national costs would be

$314 million, compared to $312 million

based on flow rates used in the 1994

proposal.

USEPA requests comment on how the

new data have been used and any

additional data that would improve the

assessment of costs and benefits.

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2. Household Costs

Household costs are a way to

represent water system treatment costs

as a costs to the system customer. Figure

14 displays results of the household cost

analyses for a 0.3 NTU, 1 maximum CFE

NTU turbidity treatment approach

discussed in this Notice. As can be seen

from the graph, a small percentage of

the systems might, using this

methodology, incur a maximum cost per

household of approximately $110 per

year. The highest household costs are

incurred in households served by small

systems that need to implement all of

the activities to comply.

It must be borne in mind that the

upper bound of the graph displays an

extrapolated curve, and does not

represent actual data points. The

assumptions and structure of this

analysis, in describing the curve, tend to

overestimate the highest costs. To find

itself on the upper bound of the curve,

a system would have to implement all,

or almost all, of the treatment activities.

These systems, conversely, might seek

less costly alternatives, such as

connecting into a larger regional water

system. In the judgment of the Advisory

Committee’s Technical Work Group,

this extreme situation and the resulting

high values may occur only for a small

number of households.

Based on this analysis, over 97

percent of the households are estimated

to incur annual costs of less than $20

per household per year and over 50

percent are estimated to incur costs of

less than $2 per household per year.

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D. Cost of Turbidity Performance

Criteria and Associated Monitoring

1. System Level Impact Analysis

The TWG developed a list of

treatment activities that systems would

be expected to employ in order to

implement Advisory Committee

recommendations. These activities were

grouped into 10 categories based on

general process descriptions as follows;

chemical addition, coagulant

improvements, rapid mixing,

flocculation improvements, settling

improvements, filtration improvements,

hydraulic improvements, administration

culture improvements, laboratory

modifications and process control

testing modifications. Descriptions of

how systems were expected to evaluate

these activities are described in the draft

document Technologies and Costs for

the Interim Enhanced Surface Water

Treatment Rule (USEPA, 1997b).

2. National Impact Analyses

a. Decision Tree. The decision tree is

a table of treatment activities that taken

either singly or in combination will help

utilities evaluate what is potentially

involved in meeting the turbidity limits

recommended by the Advisory

Committee, i.e., the requirement that

utilities serving more than 10,000

people be required to achieve a 95

percentile turbidity limit of 0.3 NTU

and at no time exceed a turbidity value

of 1 NTU (Appendix A, USEPA, 1997a).

Percentages in a decision tree represent

the projected percentage of public water

systems using that activity to meet the

turbidity limits recommended by the

Advisory Committee. These percentages

were factors in the national cost model
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and generally represent the percentage

of systems needing to modify treatment

to meet the limits.

Further description of the compliance

decision tree and methodology are

included in the draft Economic Analysis

of M/DBP Advisory Committee

Recommendations for the Interim

Enhanced Surface Water Treatment Rule

(Economic Analysis) (USEPA, 1997a).

b. Utility Costs. Turbidity Treatment.

The number of systems, the associated

total capital costs, and the associated

total annualized costs were estimated

for seven system size categories. Total

annual costs were calculated for each

possible treatment activity and for each

system size category. Unit costs were

converted to annualized cost totals (in

thousands of dollars) using the

methodology described in the draft

Economic Analysis.

As indicated in Table 14, the estimate

of national annualized turbidity

treatment costs are $203 million based

on the Advisory Committee’s

recommended 0.3 NTU 95th percentile

CFE standard while meeting a 1 NTU

maximum combined filter effluent level

(calculated with a 10% interest rate in

1997$s).

Turbidity Monitoring. A generalized

turbidity monitoring model was

developed to provide a framework for

estimating costs associated with

individual filter monitoring. The model

assumes turbidimeters for each filter

and an on-line Supervisory Control And

Data Acquisition (SCADA) system.

Filter readings would be taken at least

once every 15 minutes and tabulated.

The model assumes that once each work

shift (8 hours) the turbidity data would

be converted to a reviewable form, and

would then be reviewed by a system

manager. In cases where the monitoring

recorded exceedances as described

below, a report would be made to the

State and, if warranted, an individual

filter review or system assessment might

occur. Annual utility monitoring costs

are estimated at $96 million as shown

in Table 14 above.

Under the approach recommended by

the Advisory Committee, exception

reporting to the State is warranted if:

—An individual filter has a turbidity

level greater than 1.0 NTU for 2

consecutive measurements 15

minutes apart.

—An individual filter has a turbidity

level greater than 0.5 NTU at the end

of the first 4 hours of filter operation

for 2 consecutive measurements 15

minutes apart.

—If a plant reports exceedances of 1.0

NTU at one filter for 3 consecutive

months, an individual filter

assessment (IFA) is required to be

performed by the utility.

—If a plant records exceedances of 2.0

NTU at one filter in 2 consecutive

months, a comprehensive

performance evaluation (CPE) is

required and must be performed by a

third party.

c. State Costs. Annual Review Costs.

Under the recommended provisions, it

would be the State’s responsibility to

review system data to ensure that all

systems in the State are in compliance

with the provisions. State activities

include compliance tracking, review of

Statewide utility data, record keeping,

and compliance determinations. Annual

State costs for review (nationwide) are

estimated to be $5.3 million (USEPA,

1997a).

Implementation and Start-Up Costs

Related to Turbidity Monitoring. Onetime State implementation activities

include the adoption of the rule and

State regulation development. As shown

in Table 14, the rule would collectively

cost States a total of $407,000 to

implement turbidity monitoring

provisions.

Exception Costs (Exception Reports,

IFAs and CPEs). Under the approach

recommended by the Advisory

Committee, a monthly exception report

would be filed by each utility at which

a plant exceeds individual filter effluent

(IFE) turbidities of either 1.0 NTU for 2

consecutive measurements 15 minutes

apart, or 0.5 NTU at the end of the first

4 hours of a filter run.

In addition to the monthly exception

report of individual filter effluent

exceedances, additional steps are

triggered when exceedances persist. If

an individual filter has turbidity levels

greater than 1.0 NTU based on 2

consecutive measurements fifteen

minutes apart at any time in each of 3

consecutive months, the system

conducts a self assessment of the filter

utilizing as guidance relevant portions

of guidance issued by the

Environmental Protection Agency for

Comprehensive Performance Evaluation

(CPE). If an individual filter has

turbidity levels greater than 2.0 NTU

based on 2 consecutive measurements

fifteen minutes apart at any time in each

of two consecutive months, the system

will arrange for the conduct of a CPE by

the State or a third party approved by

the State.

The following assumptions were

made by the Technical Working Group

of the Advisory Committee regarding

the percentage of systems per year that

would trigger an interaction with the

State based on the recommended

provisions.

—10 percent of systems per year are

assumed to file monthly reports to the

State based on individual filter

effluent provisions

—2 percent of systems per year are

assumed to trigger Individual Filter

Assessment (IFA) provisions

—1 percent of systems per year are

assumed to trigger Comprehensive

Performance Evaluation (CPE)

provisions.

Based on these assumptions,

approximately 28 IFAs and 14 CPEs will

be conducted each year at an estimated

cost of $5,000 and $25,000 each,

respectively. States are expected,

therefore, to incur annual costs

(nationally) of $64,000 to review the

exception reports, $138,000 and

$345,300 in annual costs for IFAs and

CPEs, respectively. The combined total

annual State cost for these items is

$572,000 (Table 14, above).

E. Disinfection Benchmark

1. Decision Tree

The Advisory Committee

recommended that a utility prepare a

disinfection profile if they:

—measure TTHM levels of at least 80

percent of the MCL (0.064 mg/l) as an

annual average for the most recent 12-

month period for which compliance

data are available.

—measure HAA% level of at least 80

percent of the MCL (0.048 mg/l) as an

annual average for the most recent 12-

month compliance period for which

compliance data are available.

HAA and TTHM figures from the

1996 Water Industry Data Base (WIDB)

were used to estimate the percentage of

systems that would be required to

prepare a disinfection profile.

2. Utility Costs

Utility costs associated with profiling

were divided into four activity areas;

cost per system, cost per plant using

paper data (i.e., for those plants that

currently use paper to document their

plant profile data), cost per plant using

mainframe data, and cost per plant

using PC data. Plants with paper data

were assumed to represent half of the

number of plants needing profiling,

while plants with mainframe data and

plants with PC data each represent 25

percent of all plants. The TWG assumed

that all plants currently collect this data

in either an electronic or paper format,

and, therefore, would not incur

additional data collection expenses due

to microbial profiling. Data reporting

costs per plant that are associated with

microbial profiling include; data entry

and spreadsheet development, data

manipulation and analysis, and data
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59549

review. Costs per system include those

to; read and understand the rule,

mobilization and planning, generation

of reports to State and for in-house

review, and meet and review profile

with the State. The national costs

associated with microbial profiling for

utilities was estimated at $2.7 million

[Table 14].

3. State Costs

States will review profiles as part of

its sanitary survey process. Utilities

required to develop a disinfection

profile that subsequently decide to make

a significant change in disinfection

practice must consult with the state

prior to making such a change. Table 14

details the total national State costs of

profiling (one-time) at $3.1 million.

F. Sanitary Surveys

States are expected to conduct

sanitary surveys on a rotating basis, in

general no less frequently than once

every 3 years for community water

systems (CWSs) and no less frequently

than every 5 years for noncommunity

water systems (NCWSs). For this

analysis, 80 percent of Systems are

assumed to have already conducted a

sanitary survey. The remaining 20

percent of systems are considered to

require new surveys in order to comply

with the requirements in the IESWTR.

The total national cost estimate for

sanitary surveys, as shown in Table 14,

is estimated at $6.7 million.

G. Summary of Benefits Analysis

The economic benefits of the

provisions recommended by the

Advisory Committee derive from the

increased level of protection to public

health. The primary goal of these

provisions is to improve public health

by increasing the level of protection

from exposure to Cryptosporidium and

other pathogens in drinking water

supplies through improvements in

filtration at water systems. In this case,

benefits will accrue due to the

decreased likelihood of endemic

incidences of cryptosporidiosis,

giardiasis and other waterborne disease,

and the avoidance of resulting health

costs. In addition to reducing the

endemic disease, the provisions are

expected to reduce the likelihood of the

occurrence of Cryptosporidium

outbreaks and their associated economic

costs, by providing a larger margin of

safety against such outbreaks for some

systems.

The benefits analysis quantitatively

examines health damages avoided based

on the provisions recommended by the

Advisory Committee. The assessment

also discusses, but does not quantify,

other economic benefits that may result

from the provisions, including reduced

risk of outbreaks, avoided costs of

averting behavior such as boiling water.

The assessment of net benefits is

always somewhat problematic due to

the relative ease of quantifying

compliance treatment costs versus the

difficulty of assigning monetary values

to the avoidance of health damages and

other benefits arising from a regulation.

The challenge of assessing net benefits

for the recommended provisions is

compounded by the fact that there are

large areas of scientific uncertainty

regarding the exposure to and the risk

assessment for Cryptosporidium. Areas

where important sources of uncertainty

enter the benefits assessment include

the following.

• Occurrence of Cryptosporidium

oocysts in source waters.

• Occurrence of Cryptosporidium

oocysts in finished waters.

• Reduction of Cryptosporidium

oocysts due to treatment, including

filtration and disinfection.

• Viability of Cryptosporidium

oocysts after treatment.

• Infectivity of Cryptosporidium.

• Incidence of infections and

associated symptomatic response

(including impact of under reporting).

• Characterization of the risk.

• Willingness to pay to reduce risk

and avoid costs.

The cumulative impact of these

uncertainties on the outcome of the

exposure and risk assessment is

impossible to measure. The benefit

analysis attempts to take into account

some of these uncertainties by

estimating benefits under two different

current treatment assumptions and three

improved removal assumptions. The

benefit analysis also used Monte Carlo

simulations to derive a distribution of

estimates, rather than a single point

estimate.

The following two assumptions were

made about the performance of current

treatment in removing or inactivating

oocysts to estimate finished water

Cryptosporidium concentrations. The

standard assumption is that current

treatment results in a mean physical

removal and inactivation of oocysts of

2.5 logs and a standard deviation ±0.63

logs). Because the finished water

concentrations of oocysts represent the

baseline against which improved

removal from the recommended

provisions is compared, variations in

the log removal assumption could have

considerable impact on the risk

assessment. To evaluate the impact of

the removal assumptions on the

baseline and resulting improvements, an

alternative mean log removal/

inactivation assumption of 3.0 logs (and

a standard deviation ±0.63 logs) was

also used to calculate finished water

concentrations of Cryptosporidium.

USEPA made three assumptions about

the improved log removal of oocysts

that would result from the turbidity

provisions recommended by the

Advisory Committee. These were based

on studies of treatment removal

efficiencies discussed earlier in this

Notice (Table 1: Cryptosporidium and

Giardia lamblia removal efficiencies by

rapid granular filtration). A range of 2–

6 logs removal of Cryptosporidium

oocysts were observed in these studies.

USEPA assumed that a certain number

of plants would show low, mid or high

improved removal, depending upon

factors such as water matrix conditions,

filtered water turbidity effluent levels,

and coagulant treatment conditions.

The finished water Cryptosporidium

distributions that would result from

additional log removal with the

turbidity provisions were derived

assuming that additional log removal

was dependent on current removal, as

described above, i.e., that sites currently

achieving the highest filtered water

turbidity performance levels would

show the largest improvements or high

improved removal assumption (e.g.,

plants now failing to meet a 0.4 NTU

limit would show greater removal

improvements than plants now meeting

a 0.3 NTU limit). Table 15 contains the

assumptions used to generate the new

treatment distribution.

TABLE 15.—IMPROVED REMOVAL ASSUMPTIONS

Additional log removal with committee recommendations

Low Mid High

Plants now meeting 0.2 NTU limit ....................................................................................................... None None None

Plants operating between 0.2–0.3 NTU ............................................................................................... 0.15 0.25 0.3

Plants now meeting 0.4 NTU limit ....................................................................................................... 0.35 0.5 0.6
59550 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

TABLE 15.—IMPROVED REMOVAL ASSUMPTIONS—Continued

Additional log removal with committee recommendations

Low Mid High

Plants now failing to meet 0.4 NTU limit ............................................................................................. 0.5 0.75 0.9

The TWG working group assumed

that for plants to achieve a 0.3 NTU 95th

percentile standard they would operate

their plants to achieve a 0.2 NTU limit.

Therefore, systems meeting a 95th

percentile limit of 0.2 NTU were

assumed to make no further treatment

changes to meet a 0.3 NTU standard,

and therefore show no incremental

increase in log removal.

Given the uncertainties described

above, assumptions were made in

developing the risk characterization. In

summary, USEPA assumed:

—an exponential dose/response

function for estimating infection rates

(Haas et al., 1996)

—2 liters per person daily water

consumption with a log normal

distribution (Haas and Rose, 1995)

—a national surface water distribution

of oocysts based on Monte Carlo

analysis of data collected by

LeChevallier and Norton (USEPA,

1996a)

—A uniform distribution of percentage

of oocysts that would be infectious

with a mean value of 10 percent

—An estimated 0.39 mean ratio

(triangular distribution) of people that

are infected to people that become ill

(Haas, et al., 1996).

—The cost of an avoided case of

cryptosporidiosis was estimated to be

approximately $1800 per case. This

was extrapolated from the estimate of

$3,000 for giardiasis used in the RIA

for the proposal, and based on the

relatively shorter average length of

illness.

Risk characterization uses these

assumptions to calculate the number of

illnesses avoided in Table 16. Using this

number of illnesses avoided, the cost of

illnesses avoided is calculated under

each current log treatment assumption

(i.e., 2.5 and 3.0 logs) for each of the

improved removal assumptions. Table

16 summarizes the mean expected value

of potential benefits expected to accrue

to the recommended provisions under

the six different scenarios, as well as the

range.

BILLING CODE 6560–50–P
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59551

BILLING CODE 6560–50–C
59552 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

IV. National Technology Transfer and

Advancement Act

Under section 12(d) of the National

Technology Transfer and Advancement

Act (‘‘NTTAA’’), the Agency is required

to use voluntary consensus standards in

its regulatory activities unless to do so

would be inconsistent with applicable

law or otherwise impractical. Voluntary

consensus standards are technical

standards (e.g., materials specifications,

test methods, sampling procedures,

business practices, etc.) that are

developed or adopted by voluntary

consensus standards bodies. Where

available and potentially applicable

voluntary consensus standards are not

used by EPA, the Act requires the

Agency to provide Congress, through

the Office of Management and Budget,

an explanation of the reasons for not

using such standards.

The Agency does not believe that this

Notice addresses any technical

standards subject to the NTTAA. A

commenter who disagrees with this

conclusion should indicate how the

Notice is subject to the Act and identify

any potentially applicable voluntary

consensus standards.

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26, 1997.

86. Miltner RJ, EW Rice, JH Owens, FW

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87. Montgomery Watson (1995). Enhanced

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89. Moore AC, BL Herwaldt, GF Craun, RL

Calderon, AK Highsmith, and DD

Juranek (1993). Surveillance for

waterborne disease outbreaks—United

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90. Morra JJ (1979). A Review of Water

Quality Problems Caused by Various

Open Distribution Storage Reservoirs.

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91. Nieminski EC (1995). Effectiveness of

Direct Filtration and Conventional

Treatment in Removal of

Cryptosporidium and Giardia.

Proceedings AWWA Annual Conf., June

1995.

92. Nieminski EC and JE Ongerth (1995).

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by Conventional Treatment and Direct

Filtration. Jour. AWWA (Sept 1995),

87(9):96–106.

93. Ongerth JE and JP Pecoraro (1995).

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Multimedia Filters. Jour. AWWA (Dec

1995), 87(12): 83–89.

94. Owens JH, RJ Miltner, FW Schaefer III,

and EW Rice (1994). Pilot-scale ozone

inactivation of Cryptosporidium. Jour.

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95. Parker JF and HV Smith (1993).

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96. Parker JFW, GF Greaves, and HV Smith

(1993). The effects of ozone on the

viability of Cryptosporidium parvum

oocysts and a comparison of

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97. Patania NL, JG Jacangelo, L Cummings, A

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99. Pluntze JC (1974). Health aspects of

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100. Ransome ME, TN Whitmore, and EG

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89.

101. Regli S, JB Rose, CN Haas, and CP Gerba

(1991). Modeling the risk from Giardia

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102. Regli S, BA Macler, JE Cromwell, X

Zhang, AB Gelderoos, WD Grubbs, and F

Letkiewicz (1993). Framework for

decision making: EPA perspective. In:

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International Life Sciences Institute

Press, Washington, DC.

103. Rice E, J Hoff, and F Schaefer (1982).

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104. Rubin AJ, DP Evers, CM Eyman, and EL

Jarroll (1989). Inactivation of gerbilcultured Giardia lamblia cysts by free

chlorine. Applied and Environmental

Microbiology, 55(10): 2592–2594.

105. SAIC (1997). State 1 and State 2

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to the Technical Work Group. Science

Applications International Corporation

(SAIC), 1997.

106. Schuler PF and MM Ghosh (1990).

Diatomaceous earth filtration of cysts

and other particulates using chemical

additives. Journal AWWA (Dec 1990),

82(12):67–75.

107. Schuler PF and MM Ghosh (1991). Slow

Sand Filtration of Cysts and Other

Particulates. AWWA Annual Conference

Proceedings, June 1991, pp 235–252.

108. Schulmeyer PM (1995). Effect of the

Cedar River on the Quality of

Groundwater supply for Cedar Rapids,

Iowa. US Geological Survey. Water—

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109. Sethi V, P Patnaik, P Biswas, RM Clark,

and EW Rice (1997). Evaluation of

Optical Detection Methods for

Waterborne Suspensions. Journal

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110. Siddiqui MS (1996). Chlorine-ozone

interactions: Formation of chlorate.

Water Research, 30(9): 2160–2170.

111. Silverman GS, LA Nagy, and BH Olson

(1983). Variations in particulate matter,

algae, and bacteria in an uncovered,

finished-drinking-water reservoir.

Journal AWWA (Apr 1983), 75(4):191–

195.

112. Smith HV, RWA Girdwood, WJ

Patterson, et al. (1988). Waterborne

outbreak of cryptosporidiosis. Lancet 2:

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113. Solo-Gabriele H and S Neumeister

(1996). U.S. Outbreaks of

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1996), 88: 76–86.

114. Sonoma County Water Agency (1991)

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(unpublished report) and Letter from

Bruce H. Burton, P.E., District Engineer,

Santa Rosa District Office to Robert F.

Beach, General Manager Sonoma County

Water Agency.

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of Water and Wastewater (1992). Method

2130B.

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(Oct 1988).

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27544, June 29, 1989.

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1990).

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compliance with the filtration and

disinfection requirements for public

water systems using surface water

sources. Environmental Protection

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Treatment Plant Performance Using the

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625/6–91/027.

124. USEPA (1992). Consensus Method for

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127. USEPA (1994b). National Primary

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Surface Water Treatment Requirements;

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1994.

128. USEPA (1994c). Monitoring

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129. USEPA (1994d). The Regulatory Impact

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Ground Water and Drinking Water, May

1994.

130. USEPA (1994e). Training on GWUDI

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Water, USEPA. Washington DC (April

1994).

131. USEPA (1994f). January 10, 1994 letter

from Jim Elder, Director, Office of

Ground Water and Drinking Water to

John H. Sullivan, Deputy Executive

Director, AWWA.

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Microbial Pathogens and Disinfection

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Water, EPA.

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Statistical Performance of a Method for

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Source Waters,’’ (June 26, 1996), 58

pages. Appendix to the report, about 50

pages.

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Advisory Committee. Office of Ground

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1997.

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to Stig Regli dated March 21, 1997.

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Administrators (ASDWA), and National

Association of Water Companies

(NAWC) (1995). Partnership for Safe

Water Voluntary Water Treatment Plant

Performance Improvement Program SelfAssessment Procedures. October, 1995.

141. USEPA/State Joint Guidance on Sanitary

Surveys. December 1995.

142. Vaughn JM, YS Chein, JF Novotny, and

D Strout (1990). Effects of Ozone

Treatment on the Infectivity of Hepatitis

A Virus. 1990. Canadian Journal of

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143. West T, P Daniel, P Meyerhofer, A

DeGraca, S Leonard, and C Gerba (1994).

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through High-Rate Filtration.

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1994, pp 493–504.

144. Wilson MP, WD Gollnitz, SN Boutros,

and WT Boria. (1996) Determining

Groundwater Under the Direct Influence

of Surface Water. AW WA Research

Foundation, Denver CO.

Dated: October 22, 1997.

Robert Perciasepe,

Assistant Administrator.

Appendix A—U.S. Environmental Protection

Agency, Microbial/Disinfection by-Products

(M/DBP), Federal Advisory Committee

Agreement in Principle

1.0 Introduction

Pursuant to requirements under the Safe

Drinking Water Act (SDWA), the

Environmental Protection Agency (EPA) is

developing interrelated regulations to control

microbial pathogens and disinfectants/

disinfection byproducts (D/DBPs) in drinking

water. These rules are collectively known as

the microbial/disinfection byproducts (M/

DBP) rules.

The regulations are intended to address

complex risk trade-offs between the two

different types of contaminants. In keeping

with the agreement reached during the 1992–

93 negotiated rulemaking on these matters,

EPA issued a Notice of Proposed Rulemaking

for Disinfection By-Products Stage I on July

29, 1994. EPA also issued a Notice of

Proposed Rulemaking for an Interim

Enhanced Surface Water Treatment Rule

(IESWTR) on July 29, 1994. Finally, in May

1996, EPA promulgated a final Information

Collection Rule (ICR), to obtain data on

source water quality, byproduct formation

and drinking water treatment plant design

and operations.

As part of recent amendments to the

SDWA, Congress has established deadlines

for all the M/DBP rules, beginning with a

November 1998 deadline for promulgation of

both the IESWTR and the Stage I D/DBP

Rule. To meet this new deadline, EPA

initiated an expedited schedule for

development of these two rules. Building on

the 1994 proposals, EPA intends to issue a

Notice of Data Availability (NODA) in

November 1997 for public comment. EPA

also decided to establish a committee under

the Federal Advisory Committee Act (FACA)

for development of the rules.

The M/DBP Advisory Committee is made

up of organizational members (parties)

named by EPA (see Attachment A). The

immediate task of the Committee has been to

discuss, evaluate and provide advice on data,

analysis and approaches to be included in

the NODA to be published in November

1997. This Committee met four times from

March through June 1997, with the initial

objective to reach consensus, where possible,

on the elements to be contained in the D/DBP

Stage I and IESWTR NODA. Where

consensus was not reached, the Committee

sought to develop options and/or to clarify

key issues and areas of agreement and

disagreement. This document is the

Committee’s statement on the points of

agreement reached.

2.0 Agreement in Principle

The Microbial and Disinfection ByProducts Federal Advisory Committee

considered the technical and policy issues

involved in developing a DBP Stage I rule

and an IESWTR under the Safe Drinking

Water Act and recommends that the

Environmental Protection Agency base the

applicable sections of its anticipated M/DBP

Notice of Data Availability (NODA) on the

elements of agreement described below.

This agreement in principle represents the

consensus of the parties on the best

conceptual principles that the Committee

was able to generate within the allocated

time and resources available.

The USEPA, a party to the negotiations,

agrees that:

1. The person signing this agreement is

authorized to commit this party to its terms.

2. EPA agrees to hold a meeting in July

1997 following circulation of a second draft

of the NODA to obtain comments from the

parties and the public on the extent to which

the applicable sections of the draft NODA are

consistent with the agreements below.

3. Each party and individual signatory that

submits comments on the NODA agrees to

support those components of the NODA that

reflect the agreements set forth below. Each

party and individual signatory reserves the

right to comment, as individuals or on behalf

of the organization he or she represents, on

any other aspect of the Notice of Data

Availability.

4. EPA will consider all relevant comments

submitted concerning the Notice(s) of

Proposed Rulemaking and in response to

such comments will make such

modifications in the proposed rule(s) and

preamble(s) as EPA determines are

appropriate when issuing a final rule.

5. Recognizing that under the

Appointments Clause of the Constitution

governmental authority may be exercised

only by officers of the United States and

recognizing that it is EPA’s responsibility to

issue final rules, EPA intends to issue final

rules that are based on the provisions of the

Safe Drinking Water Act, pertinent facts, and

comments received from the public.

6. Each party agrees not to take any action

to inhibit the adoption of final rule(s) to the

extent it and corresponding preamble(s) have

the same substance and effect as the elements

of this agreement in principle.
59556 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules

2.1 MCLs

MCLs should remain at the levels

proposed: 0.080 mg/l for TTHMs, 0.060 mg/

l for HAA5, and 0.010 mg/l for bromate.

2.2 Enhanced Coagulation

The proposed enhanced coagulation

provisions should be revised as follows:

a. The top row of the TOC removal table

(3x3 matrix) should be modified for systems

that practice enhanced coagulation by

lowering the TOC removal percentages by

5% across the top row, while leaving the

other rows the same.

b. SUVA (specific UV absorbance) should

be used for determining whether systems

would be required to use enhanced

coagulation. The use of a raw water SUVA <

2.0 liter/mg-m as a criterion for not requiring

a system to practice enhanced coagulation

should be added to those proposed in

§ 141.135(a)(1)(i)–(iv).

c. For a system required to practice

enhanced coagulation or enhanced softening,

the use of a finished water SUVA < 2.0 liter/

mg-m should be added as a Step 2 procedure.

Such a criterion would be in addition to the

proposed Step 2 procedure, not in lieu of it.

d. The proposed TOC removals for

softening systems should be modified by

lowering the value for TOC removal in the

matrix at alkalinity >120 mg/l and TOC

between 2–4 mg/l by 5% (which would make

it equal to the value for non-softening

systems) and leaving the remaining values as

proposed.

e. If a system is required to practice

enhanced softening, lime softening plants

would not be required to perform lime soda

softening or to lower alkalinity below 40–60

mg/l as part of any Step 2 procedure.

f. There is no need to separately address

softening systems in the 3x3 matrix or the

Step 1 regulatory language, which was

identical to enhanced coagulation regulatory

language in the proposed D/DBPR. The

revised matrix should appear as follows:

Alkalinity (mg/l)

TOC (mg/

l) ......... 0¥< 60 60¥<

120

≥ 120

2–4 ........ 35 25 15

4–8 ........ 45 35 25

>8 .......... 50 40 30

2.3 Microbial Benchmarking/Profiling

A microbial benchmark to provide a

methodology and process by which a PWS

and the State, working together, assure that

there will be no significant reduction in

microbial protection as the result of

modifying disinfection practices in order to

meet MCLs for TTHM and HAA5 should be

established as follows:

A. Applicability. The following PWSs to

which the IESWTR applies must prepare a

disinfection profile:

(1) PWSs with measured TTHM levels of

at least 80% of the MCL (0.064 mg/l) as an

annual average for the most recent 12 month

compliance period for which compliance

data are available prior to November 1998 (or

some other period designated by the State),

(2) PWSs with measured HAA5 levels of at

least 80% of the MCL (0.048 mg/l) as an

annual average for the most recent 12 month

period for which data are available (or some

other period designated by the State)—In

connection with HAA5 monitoring, the

following provisions apply:

(a) PWSs that have collected HAA5 data

under the Information Collection Rule must

use those data to determine the HAA5 level,

unless the State determines that there is a

more representative annual data set.

(b) For those PWSs that do not have four

quarters of HAA5 data 90 days following the

IESWTR promulgation date, HAA5

monitoring must be conducted for four

quarters.

B. Disinfection profile. A disinfection

profile consists of a compilation of daily

Giardia lamblia log inactivations (or virus

inactivations under conditions to be

specified), computed over the period of a

year, based on daily measurements of

operational data (disinfectant residual

concentration(s), contact time(s),

temperature(s), and where necessary, pH(s)).

The PWS will then determine the lowest

average month (critical period) for each 12

month period and average critical periods to

create a ‘‘benchmark’’ reflecting the lower

bound of a PWS’s current disinfection

practice. Those PWSs that have all necessary

data to determine profiles, using operational

data collected prior to promulgation of the

IESWTR, may use up to three years of

operational data in developing those profiles.

Those PWSs that do not have three years of

operational data to develop profiles must

conduct the necessary monitoring to develop

the profile for one year beginning no later

than 15 months after promulgation, and use

up to two years of existing operational data

to develop profiles.

C. State review. The State will review

disinfection profiles as part of its sanitary

survey. Those PWSs required to develop a

disinfection profile that subsequently decide

to make a significant change in disinfection

practice (i.e., move point of disinfection,

change the type of disinfectant, change the

disinfection process, or any other change

designated as significant by the State) must

consult with the State prior to implementing

such a change. Supporting materials for such

consultation must include a description of

the proposed change, the disinfection profile,

and an analysis of how the proposed change

will affect the current disinfection.

D. Guidance. EPA, in consultation with

interested stakeholders, will develop detailed

guidance for States and PWSs on how to

develop and evaluate disinfection profiles,

identify and evaluate significant changes in

disinfection practices, and guidance on

moving the point of disinfection from prior

to the point of coagulant addition to after the

point of coagulant addition.

2.4 Disinfection Credit

Consistent with the existing provisions of

the 1989 Surface Water Treatment Rule,

credit for compliance with applicable

disinfection requirements should continue to

be allowed for disinfection applied at any

point prior to the first customer.

EPA will develop guidance on the use and

costs of oxidants that control water quality

problems (e.g., zebra mussels, Asiatic clams,

iron, manganese, algae) and whose use will

reduce or eliminate the formation of DBPs of

public health concern.

2.5 Turbidity

Turbidity Performance Requirements. For

all surface water systems that use

conventional treatment or direct filtration,

serve more than 10,000 people, and are

required to filter: (a) the turbidity level of a

system’s combined filtered water at each

plant must be less than or equal to 0.3 NTU

in at least 95 percent of the measurements

taken each month and, (b) the turbidity level

of a system’s combined filtered water at each

plant must at no time exceed 1 NTU. For

both the maximum and the 95th percentile

requirements. compliance shall be

determined based on measurements of the

combined filter effluent at four-hour

intervals.

Individual Filter Requirements. All surface

water systems that use rapid granular

filtration, serve more than 10,000 people, and

are required to filter shall conduct

continuous monitoring of turbidity for each

individual filter and shall provide an

exceptions report to the State on a monthly

basis. Exceptions reporting shall include the

following: (1) any individual filter with a

turbidity level greater than 1.0 NTU based on

2 consecutive measurements fifteen minutes

apart; and (2) any individual filter with a

turbidity level greater than 0.5 NTU at the

end of the first 4 hours of filter operation

based on 2 consecutive measurements fifteen

minutes apart. A filter profile will be

produced if no obvious reason for the

abnormal filter performance can be

identified.

If an individual filter has turbidity levels

greater than 1.0 NTU based on 2 consecutive

measurements fifteen minutes apart at any

time in each of 3 consecutive months, the

system shall conduct a self-assessment of the

filter utilizing as guidance relevant portions

of guidance issued by the Environmental

Protection Agency for Comprehensive

Performance Evaluation (CPE). If an

individual filter has turbidity levels greater

than 2.0 NTU based on 2 consecutive

measurements fifteen minutes apart at any

time in each of two consecutive months, the

system will arrange for the conduct of a CPE

by the State or a third party approved by the

State.

State Authority. States must have rules or

other authority to require systems to conduct

a Composite Correction Program (CCP) and to

assure that systems implement any follow-up

recommendations that result as part of the

CCP.

2.6 Cryptosporidium MCLG

EPA should establish an MCLG to protect

public health. The Agency should describe

existing and ongoing research and areas of

scientific uncertainty on the question of

which species of Cryptosporidium represents

a concern for public health (e.g. parvum,

muris, serpententious) and request further

comment on whether to establish an MCLG

on the genus or species level.

In the event the Agency establishes an

MCLG on the genus level, EPA should make

clear that the objective of this MCLG is to

protect public health and explain the nature

of scientific uncertainty on the issue of
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59557

taxonomy and cross reactivity between

strains. The Agency should indicate that the

scope of MCLG may change as scientific data

on specific strains of particular concern to

human health become available.

2.7 Removal of Cryptosporidium

All surface water systems that serve more

than l 0,000 people and are required to filter

must achieve at least a 2 log removal of

Cryptosporidium. Systems which use rapid

granular filtration (direct filtration or

conventional filtration treatment—as

currently defined in the SWTR), and meet the

turbidity requirements described in Section

2.5 are assumed to achieve at least a 2 log

removal of Cryptosporidium. Systems which

use slow sand filtration and diatomaceous

earth filtration and meet existing turbidity

performance requirements (less than 1 NTU

for the 95th percentile or alternative criteria

as approved by the State) are assumed to

achieve at least a 2 log removal of

Cryptosporidium.

Systems may demonstrate that they

achieve higher levels of physical removal.

2.8 Multiple Barrier Concept

EPA should issue a risk-based proposal of

the Final Enhanced Surface Water Treatment

Rule for Cryptosporidium embodying the

multiple barrier approach (e.g. source water

protection, physical removal, inactivation,

etc.), including, where risks suggest

appropriate, inactivation requirements. In

establishing the Final Enhanced Surface

Water Treatment Rule, the following issues

will be evaluated:

• Data and research needs and limitations

(e.g. occurrence, treatment, viability, active

disease surveillance, etc.);

• Technology and methods capabilities

and limitations;

• Removal and inactivation effectiveness;

• Risk tradeoffs including risks of

significant shifts in disinfection practices;

• Cost considerations consistent with the

SDWA;

• Reliability and redundancy of systems;

• Consistency with the requirements of the

Act.

2.9 Sanitary Surveys

Sanitary surveys operate as an important

preventive tool to identify water system

deficiencies that could pose a risk to public

health. EPA and ASDWA have issued a joint

guidance dated 12/21/95 on the key

components of an effective sanitary survey.

The following provisions concerning sanitary

surveys should be included.

I. Definition

(A) A sanitary survey is an onsite review

of the water source (identifying sources of

contamination using results of source water

assessments where available), facilities,

equipment, operation, maintenance, and

monitoring compliance of a public water

system to evaluate the adequacy of the

system, its sources and operations and the

distribution of safe drinking water.

(B) Components of a sanitary survey may

be completed as part of a staged or phased

state review process within the established

frequency interval set forth below.

(C) A sanitary survey must address each of

the eight elements outlined in the December

1995 EPA/STATE Guidance on Sanitary

Surveys.

II. Frequency

(A) Conduct sanitary surveys for all surface

water systems (including groundwater under

the influence) no less frequently than every

three years for community systems except as

provided below and no less frequently than

every five years for noncommunity systems.

—May ‘‘grandfather’’sanitary surveys

conducted after December 1995, if

they address the eight sanitary survey

components outlined above.

(B) For community systems determined by

the State to have outstanding performance

based on prior sanitary surveys, successive

sanitary surveys may be conducted no less

than every five years.

III. Follow Up

(A) Systems must respond to deficiencies

outlined in a sanitary survey report within at

least 45 days, indicating how and on what

schedule the system will address significant

deficiencies noted in the survey.

(B) States must have the appropriate rules

or other authority to assure that facilities take

the steps necessary to address significant

deficiencies identified in the survey report

that are within the control of the PWS and

its governing body.

Agreed to by:

lllllllllllllllllllll

Name, Organization

lllllllllllllllllllll

Date

Signed By:

Peter L. Cook, National Association of Water

Companies

Michael A. Dimitriou, International Ozone

Association

Cynthia C. Dougherty, US Environmental

Protection Agency

Mary J.R. Gilchrist, American Public Health

Association

Jeffrey K. Griffiths, National Association of

People with AIDS

Barker Hamill, Association of State Drinking

Water Administrators

Robert H. Harris, Environmental Defense

Fund

Edward G. Means III, American Water Works

Association

Rosemary Menard, Large Unfiltered Systems

Erik D. Olson, Natural Resources Defense

Council

Brian L. Ramaley, Association of

Metropolitan Water Agencies

Charles R. Reading Jr., Water and Wastewater

Equipment Manufacturers Association

Suzanne Rude, National Association of

Regulatory Utility Commissioners

Ralph Runge, Chlorine Chemistry Council

Coretta Simmons, National Association of

State Utility Consumer Advocates

Bruce Tobey, National League of Cities

Chris J. Wiant, National Association of City

and County Health Officials; National

Environmental Health Association

[FR Doc. 97–28747 Filed 10–31–97; 8:45 am]

BILLING CODE 6560–50–P