Document ID: EPA-HQ-OW-2002-0039-0042
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2003-07-09T04:00Z

LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
1
1.0
Introduction
In
establishing
drinking
water
regulations
for
microbial
and
disinfection
byproduct
(
MDBP
control,
the
U.
S.
Environmental
Protection
Agency
(
EPA)
is
promoting
a
multi­
barrier
approach
for
treating
drinking
water.
A
multi­
barrier
treatment
process
provides
a
number
of
protective
"
layers"
against
contamination
by
using
more
than
one
method
of
prevention
and
treatment
to
remove
or
inactivate
microorganisms
and
minimize
disinfection
byproducts
(
DBPs).
To
that
end,
EPA
is
publishing
this
guidance
to
help
public
water
systems
(
PWSs)
choose
appropriate
combinations
of
treatment
processes
for
compliance
with
the
Long
Term
2
Enhanced
Surface
Water
Treatment
Rule
(
LT2ESWTR).

The
LT2ESWTR
focuses
on
improved
control
of
microbial
contamination,
specifically
the
protozoan
parasite
Cryptosporidium.
Differing
from
previous
drinking
water
regulations,
the
LT2ESWTR
requirements
for
each
system
are
based
on
the
PWS's
vulnerability
to
contamination,
as
measured
by
the
occurrence
of
Cryptosporidium
in
the
source
water.
This
"
Microbial
Framework"
strategy
stems
from
a
recognition
that
only
some
systems
may
need
to
provide
additional
protection
against
Cryptosporidium
and
that
such
decisions
should
be
made
on
a
system­
specific
basis.

With
this
approach,
systems
initially
conduct
source
water
monitoring
to
determine
average
Cryptosporidium
concentrations
(
small
filtered
systems
first
monitor
for
E.
coli
to
determine
if
Cryptosporidium
monitoring
is
required).
Based
on
their
monitoring
results,
systems
are
classified
into
different
categories
(
or
bins).
The
bins
indicate
the
additional
Cryptosporidium
treatment
requirements,
if
any,
that
must
be
met
to
comply
with
the
rule.
Systems
required
to
provide
additional
treatment
will
choose
from
a
"
toolbox"
of
options
consisting
of
treatment
technologies,
process
optimization
techniques,
and
management
techniques
to
meet
the
requirements.
Thus,
this
approach
requires
enhanced
Cryptosporidium
treatment
for
systems
with
higher
vulnerability
to
Cryptosporidium
contamination
and
provides
several
options
for
those
systems
to
achieve
compliance.
These
options
are
described
in
this
manual.

1.1
Objectives
The
primary
objectives
of
this
manual
are
to
provide
guidance
to
public
water
systems
for
selecting
appropriate
toolbox
options
and
achieving
compliance
for
each
option.
To
accomplish
these
objectives,
this
manual
will
describe
each
toolbox
option
in
terms
of
achieving
Cryptosporidium
treatment
credit(
s)
and
discuss
design
and
operational
issues
systems
should
consider
for
each
option.

1.2
Organization
This
manual
consists
of
fifteen
chapters
and
appendices:
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
2
Chapter
1
Introduction
­
The
remainder
of
this
chapter
summarizes
the
LT2ESWTR,
presents
the
bin
classifications
for
conventional
treatment
plants,
direct
filtration
plants,
and
plants
with
other
treatment
technologies
(
i.
e.,
softening,
slow
sand
filtration,
and
diatomaceous
earth
filtration),
and
defines
those
processes
in
the
context
of
the
LT2ESWTR.

Chapters
2
­
14
Toolbox
Options
­
These
chapters
describe
each
toolbox
option
and
how
systems
can
implement
these
options
to
achieve
the
associated
Cryptosporidium
treatment
credit.
Where
applicable,
basic
design
criteria
are
recommended
to
achieve
a
given
log
removal.
Each
chapter
contains
its
own
list
of
references.

Appendix
A
Site
Specific
Determination
of
Contact
Time
for
Chlorine
Dioxide
and
Ozone
­
describes
the
different
elements
of
a
site
specific
study
to
generate
a
set
of
chlorine
dioxide
or
ozone
CT
values
for
that
site
and
discusses
some
of
the
issues
involved
in
the
statistical
analysis
of
the
results.

Appendix
B
Ozone
CT
Methods
­
describes
the
Segmented
Flow
Analysis
and
Extended­
CSTR
methods
to
calculate
the
CT
inactivation
credits
with
ozone.

Appendix
C
Measuring
Ozone
Residual
­
discusses
ozone
residual
sample
collection,
measurement,
and
online
ozone
residual
analyzer
calibration.

Appendix
D
Derivation
of
SFA
and
Extended
CSTR
Equations
­
provides
derivations
for
the
Segmented
Flow
Analysis
equation
and
the
equation
used
to
calculate
k*.

Appendix
E
Watershed
Control
Best
Management
Practices
(
BMPs)
­
provides
a
list
of
programmatic
resources
and
guidance
available
to
assist
systems
in
building
partnerships
and
implementing
watershed
protection
activities.

1.3
Existing
Regulations
and
Treatment
Requirements
The
following
sections
describe
the
predecessors
to
the
LT2ESWTR,
along
with
the
Stage
1
Disinfectants
and
Disinfection
Byproducts
Rule
(
DBPR),
which
was
promulgated
to
reduce
the
formation
of
DBPs
in
the
plant
and
distribution
system.
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
3
1.3.1
Surface
Water
Treatment
Rule
Under
the
1989
Surface
Water
Treatment
Rule
(
SWTR)
(
54
FR
27486),
EPA
established
treatment
requirements
for
all
PWSs
using
surface
water
or
ground
water
under
the
direct
influence
of
surface
water
(
GWUDI)
as
a
source.
The
requirements
are
intended
to
protect
against
the
adverse
health
effects
associated
with
Giardia
lamblia,
viruses,
and
Legionella
and
include
the
following:

Maintenance
of
a
disinfectant
residual
in
water
entering
and
within
the
distribution
system.

Removal/
inactivation
of
at
least
99.9
percent
(
3
log)
of
Giardia
and
99.99
percent
(
4
log)
of
viruses.

Filtration,
unless
systems
meet
specified
avoidance
criteria.

For
filtered
systems,
a
turbidity
limit
for
the
combined
filter
effluent
of
5
nephelometric
turbidity
units
(
NTUs)
at
any
time
and
a
limit
of
0.5
NTU
in
95
percent
of
measurements
each
month
for
treatment
plants
using
conventional
treatment
or
direct
filtration
(
with
separate
standards
for
other
filtration
technologies).
These
requirements
were
superseded
by
the
1998
IESWTR
and
the
2002
LT1ESWTR.

Watershed
control
programs
and
water
quality
requirements
for
unfiltered
systems.

1.3.2
Interim
Enhanced
Surface
Water
Treatment
Rule
The
Interim
Enhanced
Surface
Water
Treatment
Rule
(
IESWTR)
(
63
FR
69478)
applies
to
PWSs
serving
at
least
10,000
people
and
using
surface
water
or
GWUDI
as
a
source.
These
systems
were
to
comply
with
the
IESWTR
by
January
2002.
The
requirements
and
guidelines
include:

Removal
of
99
percent
(
2
log)
of
Cryptosporidium
for
systems
that
provide
filtration

For
treatment
plants
using
conventional
treatment
or
direct
filtration,
a
turbidity
performance
standard
for
the
combined
effluent
of
filters
of
1
NTU
as
a
maximum
and
0.3
NTU
as
a
maximum
in
95
percent
of
monthly
measurements,
based
on
4­
hour
monitoring
(
these
limits
supersede
the
SWTR
turbidity
limits)

Continuous
monitoring
of
individual
filter
effluent
turbidity
in
conventional
and
direct
filtration
plants
and
recording
of
turbidity
readings
every
15
minutes
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
4

A
disinfection
benchmark
to
assess
the
level
of
microbial
protection
provided
before
facilities
change
their
disinfection
practices
to
meet
the
requirements
of
the
Stage
1
DBPR

Inclusion
of
Cryptosporidium
in
the
definition
of
GWUDI
and
in
the
watershed
control
requirements
for
unfiltered
PWSs

All
new
finished
water
reservoirs
must
be
covered.

1.3.3
Stage
1
Disinfectants
and
Disinfection
Byproducts
Rule
Pursuant
to
requirements
under
the
Safe
Drinking
Water
Act
(
SDWA),
EPA
developed
interrelated
regulations
to
control
microbial
pathogens
and
disinfectants/
DBPs
in
drinking
water.
These
rules,
collectively
known
as
the
M­
DBP
rules,
are
intended
to
address
complex
risk
trade­
offs
between
the
two
different
types
of
contaminants.
EPA
promulgated
the
IESWTR
concurrently
with
the
Stage
1
DBPR
so
that
systems
could
coordinate
their
responses
to
the
risks
posed
by
DBPs
and
microbial
pathogens.

The
1998
Stage
1
DBPR
(
63
FR
69390)
applies
to
all
community
water
systems
(
CWSs)
and
nontransient
noncommunity
water
systems
(
NTNCWSs)
that
add
a
chemical
disinfectant
to
their
water.
Certain
requirements
in
the
rule
also
apply
to
transient
noncommunity
water
systems
(
TNCWSs).
Surface
water
and
GWUDI
systems
serving
at
least
10,000
people
were
required
to
comply
with
the
rule
by
January
2002.
All
other
systems
(
including
ground
water
systems)
must
comply
by
January
2004.

The
Stage
1
DBPR
sets
maximum
residual
disinfectant
levels
(
MRDLs)
for
chlorine,
chloramines,
and
chlorine
dioxide;
and
maximum
contaminant
levels
(
MCLs)
for
total
trihalomethanes
(
TTHM),
haloacetic
acids
(
HAA5),
bromate,
and
chlorite.
The
MRDLs
and
MCLs,
except
those
for
chlorite
and
chlorine
dioxide,
are
calculated
as
running
annual
averages.
For
conventional
filtration
systems,
enhanced
coagulation/
softening
is
the
best
available
treatment
technique
for
removal
of
DBP
precursors.

1.3.4
Long
Term
1
Enhanced
Surface
Water
Treatment
Rule
The
Long
Term
1
Enhanced
Surface
Water
Treatment
Rule
(
LT1ESWTR)
(
67
FR
1811)
was
promulgated
in
2002
and
extends
most
of
the
requirements
of
the
IESWTR
to
surface
water
and
GWUDI
systems
serving
fewer
than
10,000
people.
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
5
1.4
Microbial­
Disinfection
Byproduct
Rule
Summary
In
keeping
with
a
phased
M­
DBP
strategy,
EPA
developed
the
Stage
2
DBPR
and
LT2ESWTR.
These
rules
are
summarized
below.

1.4.1
Stage
2
Disinfectant
and
Disinfection
Byproduct
Rule
The
requirements
of
the
Stage
2
DBPR
apply
to
all
community
water
systems
(
CWSs)
and
nontransient
noncommunity
water
systems
(
NTNCWSs)
 
both
ground
and
surface
water
systems
 
that
add
a
disinfectant
other
than
ultraviolet
light
(
UV),
or
that
deliver
water
that
has
been
treated
with
a
disinfectant
other
than
UV.

Initial
Distribution
System
Evaluations
The
Stage
2
DBPR
is
designed
to
reduce
DBP
occurrence
peaks
in
the
distribution
system
by
changing
compliance
monitoring
requirements
and
the
procedure
for
determining
compliance.
Compliance
monitoring
will
be
preceded
by
an
initial
distribution
system
evaluation
(
IDSE)
to
identify
compliance
monitoring
locations
that
represent
high
TTHM
and
HAA5
levels.
The
IDSE
consists
of
either
a
standard
monitoring
program
(
SMP)
or
a
system­
specific
study
(
SSS).
NTNCWSs
serving
fewer
than
10,000
people
are
not
required
to
perform
an
IDSE,
and
other
systems
may
receive
waivers
from
the
IDSE
requirement.

Compliance
Determination
and
Schedule
The
Stage
2
DBPR
changes
the
way
sampling
results
are
averaged
to
determine
compliance.
The
determination
for
the
Stage
2
DBPR
is
based
on
a
locational
running
annual
average
(
LRAA)
(
i.
e.,
compliance
must
be
met
at
each
monitoring
location)
instead
of
the
system­
wide
running
annual
average
(
RAA)
used
under
the
Stage
1
DBPR.

The
Stage
2
DBPR
will
be
implemented
in
two
phases,
Stage
2A
and
Stage
2B.
Under
Stage
2A,
all
systems
must
comply
with
TTHM/
HAA5
MCLs
of
120/
100
µ
g/
L
measured
as
LRAAs
at
each
Stage
1
DBPR
monitoring
site,
while
continuing
to
comply
with
the
Stage
1
DBPR
MCLs
of
80/
60
µ
g/
L
measured
as
RAAs.
Under
Stage
2B,
systems
must
comply
with
TTHM/
HAA5
MCLs
of
80/
60
µ
g/
L
at
locations
identified
under
the
IDSE.

Compliance
Monitoring
Systems
will
continue
to
monitor
at
their
Stage
1
DBPR
compliance
monitoring
sites
for
the
Stage
2A
DBPR.
The
Stage
2B
DBPR
compliance
monitoring
sites
will
be
determined
from
the
results
of
the
IDSE.
Stage
2B
compliance
monitoring
requirements
(
number
of
sites
and
frequency
of
sampling)
will
be
similar
to
the
Stage
1
DBPR
requirements
for
most,
but
not
all,
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
6
systems.
Some
small
systems
will
have
to
add
an
additional
monitoring
location
if
their
highest
TTHM
and
highest
HAA5
site
do
not
occur
at
the
same
location.

Significant
Excursion
Evaluations
Because
Stage
2
DBPR
MCL
compliance
is
based
on
an
annual
average
of
DBP
measurements,
a
system
could
from
time
to
time
have
DBP
levels
significantly
higher
than
the
MCL
(
referred
to
as
a
significant
excursion)
while
still
being
in
compliance.
This
is
because
the
high
concentration
could
be
averaged
with
lower
concentrations
at
a
given
location.
If
a
significant
excursion
occurs,
a
system
must
conduct
a
significant
excursion
evaluation
and
discuss
the
evaluation
with
the
State
no
later
than
the
next
sanitary
survey.

1.4.2
Long
Term
2
Enhanced
Surface
Water
Treatment
Rule
1.4.2.1
Filtered
Systems
The
LT2ESWTR
requires
systems
that
use
a
surface
water
or
GWUDI
source
(
referred
to
collectively
in
this
manual
as
surface
water
systems)
and
provide
filtration
to
conduct
source
water
monitoring
to
determine
average
Cryptosporidium
concentrations,
unless
they
have
historical
Cryptosporidium
data
equivalent
to
what
is
required
under
the
LT2ESWTR
(
40
CFR
141.701(
a)).
Based
on
its
average
source
water
Cryptosporidium
concentration,
a
system
will
be
classified
in
one
of
four
possible
bins.
A
system's
bin
assignment
determines
the
extent
of
any
additional
Cryptosporidium
treatment
requirements.
The
rule
requires
systems
to
comply
with
additional
treatment
requirements
by
using
one
or
more
management
or
treatment
techniques
from
the
toolbox
of
options
(
40
CFR
141.720(
b)).
The
process
is
described
in
more
detail
below;
the
full
monitoring
requirements
are
described
in
the
Source
Water
Monitoring
Guidance
Manual
for
Public
Water
Systems
for
the
Long
Term
2
Enhanced
Surface
Water
Treatment
Rule
(
USEPA
2003).

Monitoring
Requirements
The
LT2ESWTR
specifies
two
monitoring
schemes
for
filtered
systems
serving
at
least
10,000
people.
The
first
is
that
the
system
collect
at
least
24
samples,
but
not
more
than
47
samples,
over
a
2­
year
period
and
base
the
bin
assignment
on
the
maximum
running
annual
average
(
RAA)
(
40
CFR141.709(
b(
1)).
(
The
first
RAA
will
be
the
average
of
the
results
of
the
first
12
months
of
monitoring;
the
second
RAA
will
be
the
average
of
results
from
months
2
 
13,
the
third
will
be
the
average
of
concentrations
from
months
3
 
14,
etc.)
Alternatively,
systems
may
collect
two
or
more
samples
per
month
over
the
2­
year
period
and
use
the
average
of
all
samples
to
determine
bin
placement
(
40
CFR
141.709(
b(
1))).

For
filtered
systems
serving
fewer
than
10,000
people,
the
LT2ESWTR
requires
those
systems
to
first
monitor
for
E.
coli
(
or
an
indicator
approved
by
the
State)
at
least
every
two
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
7
weeks
for
12
months;
based
on
the
results,
they
may
be
required
to
conduct
Cryptosporidium
monitoring
at
least
twice
a
month
for
12
months
(
40
CFR
141.701(
e)).
Systems
that,
based
on
their
E.
coli
results,
do
not
have
to
monitor
Cryptosporidium
are
placed
in
Bin
1
(
see
Table
1.1).
Systems
that
must
conduct
Cryptosporidium
monitoring
include
the
following
(
40
CFR
141.702(
b)):

Systems
that
use
lakes
or
reservoirs
as
sources
and
that
have
an
average
E.
coli
concentration
of
more
than
10
E.
coli
per
100
milliliters
(
mL).

Those
systems
that
use
flowing
streams
as
sources
and
that
have
an
average
E.
coli
concentration
of
more
than
50
E.
coli
per
100
mL.

For
those
systems
triggered
into
Cryptosporidium
monitoring,
bin
assignment
is
based
on
the
average
Cryptosporidium
concentration
of
the
24
required
samples
(
40
CFR
141.709(
b(
3))).

Bin
Classification
Table
1.1
presents
the
bin
classifications
and
their
corresponding
additional
treatment
requirements
for
all
filtered
systems
(
40
CFR
141.709
and
40
CFR
141.720).
Systems
with
average
Cryptosporidium
concentrations
of
less
than
0.075
oocysts
per
liter
are
placed
in
Bin
1,
for
which
no
additional
treatment
is
required.
For
concentrations
of
0.075
or
more,
additional
treatment
is
required
on
top
of
that
required
by
existing
rules.
The
additional
treatment
required
for
each
bin,
specified
in
terms
of
log
removal,
depends
on
the
type
of
treatment
already
in
place
in
the
system.
Chapter
1
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Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
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June
2003
1­
8
Table
1.1
Bin
Requirements
for
Filtered
Plants1
If
your
Cryptosporidium
concentration
(
oocysts/
L)
is...
Your
bin
classification
is...
And
if
you
use
the
following
filtration
treatment
in
full
compliance
with
existing
regulations,
then
your
additional
treatment
requirements
are...

Conventional
Filtration
Treatment
(
includes
softening)
Direct
Filtration
Slow
Sand
or
Diatomaceous
Earth
Filtration
Alternative
Filtration
Technologie
s
<
0.075
1
No
additional
treatment
No
additional
treatment
No
additional
treatment
No
additional
treatment
>
0.075
and
<
1.0
2
1
log
treatment2
1.5
log
treatment2
1
log
treatment2
As
determined
by
the
State2,4
>
1.0
and
<
3.0
3
2
log
treatment3
2.5
log
treatment3
2
log
treatment3
As
determined
by
the
State3,5
>
3.0
4
2.5
log
treatment3
3
log
treatment3
2.5
log
treatment3
As
determined
by
the
State3,6
1
(
40
CFR
141.709
and
40
CFR
141.720)
2
Systems
may
use
any
technology
or
combination
of
technologies
from
the
microbial
toolbox.
3
Systems
must
achieve
at
least
1
log
of
the
required
treatment
using
ozone,
chlorine
dioxide,
UV,
membranes,
bag/
cartridge
filters,
or
bank
filtration.
4
Total
Cryptosporidium
treatment
must
be
at
least
4.0
log.
5
Total
Cryptosporidium
treatment
must
be
at
least
5.0
log.
6
Total
Cryptosporidium
treatment
must
be
at
least
5.5
log.

Additional
Treatment
Requirements
The
total
Cryptosporidium
treatment
required
for
Bins
2,
3,
and
4
is
4.0
log,
5.0
log,
and
5.5
log,
respectively.
The
additional
treatment
requirements
in
Table
1.1
are
based
on
a
determination
that
conventional,
slow
sand,
and
diatomaceous
earth
filtration
plants
in
compliance
with
the
IESWTR
or
LT1ESWTR
achieve
an
average
of
3
log
removal
of
Cryptosporidium
(
the
2
log
credit
for
Cryptosporidium
under
the
IESWTR
and
LT1ESWTR
is
based
on
the
minimum
removal
expected
with
these
types
of
filtration).
Therefore,
conventional,
slow
sand,
and
diatomaceous
earth
filtration
plants
will
require
an
additional
1.0
to
2.5
log
additional
treatment
to
meet
the
total
removal
requirement,
depending
on
the
bin
they
are
placed
in.

Conventional
treatment
is
a
treatment
train
with
coagulation,
flocculation,
sedimentation,
and
granular
media
filtration.
Sedimentation
is
defined
in
40
CFR
141.2
as
a
process
for
removal
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
9
of
solids
before
filtration
by
gravity
or
separation.
Solid/
liquid
separation
processes
with
solids
removal
capability
include
gravity
sedimentation
(
traditional,
plate,
tube,
ballasted
sand),
dissolved
air
flotation
(
DAF),
solids
contact
clarifiers,
and
buoyant
and
non­
buoyant
media
clarifiers.

Direct
filtration
plants
have
coagulation,
flocculation,
and
filtration
processes,
like
conventional
treatment,
but
lack
a
sedimentation
process.
By
providing
a
second
pathogen
barrier,
a
sedimentation
basin
enhances
the
overall
removal
efficiency
and
stability
of
the
treatment
train.
EPA
has
determined
that
direct
filtration
plants
achieve
an
average
2.5
log
removal
of
Cryptosporidium.
Consequently,
under
the
LT2ESWTR,
direct
filtration
plants
in
Bins
2
 
4
must
provide
0.5
log
more
in
additional
treatment
than
conventional
plants
to
meet
the
total
Cryptosporidium
removal
requirement.

The
LT2ESWTR
specifies
that
a
State
may
award
greater
credit
to
a
system
demonstrating
through
a
State­
approved
protocol
that
it
reliably
achieves
a
higher
level
of
Cryptosporidium
removal
(
40
CFR
141.727(
c)).
Conversely,
a
State
may
award
less
credit
to
a
system
where
the
State
determines,
based
on
site­
specific
information,
that
the
system
is
not
achieving
the
degree
of
Cryptosporidium
removal
indicated
in
Table
1.1
(
40
CFR
141.727(
c)).

For
systems
using
alternative
filtration
technologies,
such
as
bag
or
cartridge
filters,
the
LT2ESWTR
specifies
that
the
State
will
determine
additional
treatment
requirements
based
on
the
credit
awarded
to
a
particular
technology.
The
additional
treatment
must
be
such
that
plants
in
Bins
2,3,
and
4
achieve
the
total
required
Cryptosporidium
reductions
of
4.0,
5.0,
and
5.5
log,
respectively
(
40
CFR
141.720).

Systems
in
Bin
2
can
meet
additional
Cryptosporidium
treatment
requirements
by
using
an
option
or
combination
of
options
in
the
toolbox
(
40
CFR
141.720(
b)).
In
Bins
3
and
4,
systems
must
achieve
at
least
1
log
of
the
additional
treatment
requirement
through
use
of
ozone,
chlorine
dioxide,
ultraviolet
light,
membrane
filtration,
bag
filtration,
cartridge
filtration,
or
bank
filtration
(
40
CFR
141.720(
c)).

1.4.2.2
Unfiltered
Systems
All
existing
requirements
for
unfiltered
systems
under
the
SWTR
(
40
CFR,
parts
141.71
and
72(
a))
remain
in
effect.
This
includes
disinfection
to
achieve
at
least
3
log
inactivation
of
Giardia
and
4
log
inactivation
of
viruses
and
to
maintain
a
disinfectant
residual
in
the
distribution
system
(
e.
g.,
free
chlorine
or
chloramines).
The
IESWTR
and
LT1ESWTR
did
not
change
the
disinfection
requirements
for
unfiltered
systems.

Under
the
LT2ESWTR,
unfiltered
systems
are
required
to
monitor
their
source
water
for
Cryptosporidium
to
determine
the
amount
of
treatment
required
(
40
CFR
141.701(
d)).
Systems
serving
10,000
or
more
people
must
monitor
at
least
once
a
month
for
two
years
(
40
CFR
141.701(
e)).
Systems
serving
fewer
than
10,000
people
must
monitor
at
least
twice
a
month
for
Chapter
1
­
Introduction
LT2ESWTR
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June
2003
1­
10
one
year
(
40
CFR
141.701(
e)).
All
small
unfiltered
systems
must
monitor
Cryptosporidium;
there
is
no
exception
based
on
E.
coli
monitoring
results
as
there
is
for
small
filtered
systems.
These
monitoring
requirements
are
described
in
detail
in
the
Source
Water
Monitoring
Guidance
Manual
(
USEPA
2003).

The
arithmetic
mean
concentration
of
all
Cryptosporidium
samples
taken
is
used
to
determine
the
amount
of
treatment
required,
as
shown
in
Table
1.2
(
40
CFR
141.721(
a)).
If
the
mean
concentration
is
less
than
or
equal
to
0.01
oocysts/
L,
the
system
must
provide
2
log
inactivation
of
Cryptosporidium
(
40
CFR
141.721(
b)).
If
the
mean
concentration
of
Cryptosporidium
exceeds
0.01
oocysts/
L,
the
system
must
provide
at
least
3
log
inactivation
of
Cryptosporidium
(
40
CFR
141.721(
b)).

Table
1.2
LT2ESWTR
Treatment
Requirements
for
Unfiltered
Systems
Average
Cryptosporidium
Concentration
(
oocysts/
liter)
Additional
Cryptosporidium
Inactivation
Requirements
<
0.01
2
log1
>
0.01
3
log1
1Overall
disinfection
requirements
must
be
met
with
a
minimum
of
two
disinfectants.

The
LT2ESWTR
requires
unfiltered
systems
to
meet
overall
disinfection
requirements
(
i.
e.,
Cryptosporidium,
Giardia,
and
virus
inactivation)
using
a
minimum
of
two
disinfectants
(
40
CFR
141.721(
d)).
Disinfectants
that
can
be
used
to
meet
this
requirement
include
ozone,
ultraviolet
(
UV)
light,
and
chlorine
dioxide.
(
Refer
to
the
UV
Guidance
Manual
for
rule
requirements
and
guidance
regarding
UV
systems.)
Further,
each
of
the
two
disinfectants
must
achieve
by
itself
the
total
inactivation
required
for
one
of
the
three
pathogen
types.
For
example,
a
system
could
use
UV
light
to
achieve
2
log
inactivation
of
Cryptosporidium
and
Giardia,
and
use
chlorine
to
inactivate
1
log
Giardia
and
4
log
viruses.
In
this
case
chlorine
would
achieve
the
total
inactivation
required
for
viruses,
while
UV
light
would
achieve
the
total
inactivation
required
for
Cryptosporidium
and
Giardia,
and
the
two
disinfectants
together
would
meet
the
overall
treatment
requirements
for
viruses,
Giardia,
and
Cryptosporidium.

1.4.2.3
Uncovered
Finished
Water
Reservoirs
The
LT2ESWTR
requires
systems
with
uncovered
finished
water
reservoirs
to
cover
the
uncovered
finished
water
reservoir,
treat
the
reservoir
discharge
to
the
distribution
system
to
achieve
a
4
log
virus
inactivation,
or
implement
a
risk
mitigation
plan
(
40
CFR
141.724).
The
LT2ESWTR
specifies
that
risk
mitigation
plans
address
physical
access,
surface
water
run­
off,
animal
and
bird
waste,
and
continuous
water
quality
assessment
(
40
CFR
141.724(
a)(
3))).
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
11
1.5
Summary
of
Microbial
Toolbox
Options
The
LT2ESWTR
requires
systems
to
use
one
or
more
of
the
microbial
toolbox
options
described
in
Table
1.3
(
40
CFR
141.722).
Components
of
the
toolbox
include
watershed
control
programs,
alternative
sources,
pretreatment
process,
additional
filtration
barriers,
inactivation
technologies,
and
enhanced
plant
performance.
The
intent
of
the
toolbox
is
to
provide
systems
with
flexibility
in
selecting
cost­
effective
LT2ESWTR
compliance
strategies.

In
most
cases,
systems
will
receive
presumptive
log
credit
for
a
toolbox
option
by
demonstrating
compliance
with
required
design
and
implementation
criteria.
The
demonstration
of
performance
option
allows
States
to
approve
a
treatment
credit
greater
than
the
presumptive
log
credit
based
on
a
site­
specific
or
technology­
specific
demonstration
of
performance
(
40
CFR
141.727(
c)).

Systems
may
use
a
combination
of
toolbox
options
to
achieve
the
required
log
treatment.
For
example,
a
conventional
filtration
system
assigned
to
Bin
3,
requiring
an
additional
2
log
treatment,
can
implement
ozone
with
a
contact
time
and
concentration
yielding
1.5
log
credit
and
achieve
the
requirements
for
combined
filter
performance,
thus
receiving
an
additional
0.5
log
credit
for
a
total
of
2
log
credit.

Table
1.3
Summary
of
Microbial
Toolbox
Options
with
Available
Log
Credits
and
Design/
Implementation
Criteria
Toolbox
Option
Cryptosporidium
Treatment
Credit
with
Design
and
Implementation
Criteria
Source
Toolbox
Components
Watershed
control
program
0.5
log
credit
for
State
approved
program
comprised
of
EPA
specified
elements.
Specific
criteria
are
in
40
CFR
141.725(
a).
See
Chapter
2
of
this
manual.

Alternative
source/
intake
management
No
presumptive
credit.
Systems
may
conduct
simultaneous
monitoring
for
LT2ESWTR
bin
classification
at
alternative
intake
locations
or
under
alternative
intake
management
strategies.
See
40
CFR
141.725(
b).
See
Chapter
3.

Pre­
Filtration
Toolbox
Components
Bank
filtration
0.5
log
credit
for
25
foot
setback;
1.0
log
credit
for
50
foot
setback.
Aquifer
must
be
unconsolidated
sand
containing
at
least
10%
fines.
Average
turbidity
in
wells
must
be
<
1
NTU.
Systems
with
existing
wells
must
monitor
well
effluent
to
determine
bin
classification
and
are
not
eligible
for
presumptive
credit.
See
40
CFR
141.726(
c).
See
Chapter
4.
Chapter
1
­
Introduction
Toolbox
Option
Cryptosporidium
Treatment
Credit
with
Design
and
Implementation
Criteria
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
12
Presedimentation
basin
with
coagulation
0.5
log
credit
for
new
basins
with
continuous
operation
and
coagulant
addition.
Basins
must
achieve
0.5
log
turbidity
reduction
based
on
the
monthly
mean
of
daily
measurements
in
11
of
the
12
previous
months.
All
flow
must
pass
through
basins.
Systems
with
existing
pre­
sed
basins
must
monitor
after
basins
to
determine
bin
classification
and
are
not
eligible
for
presumptive
credit.
See
40
CFR
141.726(
a).
See
Chapter
5.

Two­
stage
lime
softening
0.5
log
credit
for
two­
stage
softening
with
coagulant
addition.
Coagulant
must
be
present
in
both
clarifiers
and
includes
metal
salts,
polymers,
lime,
or
magnesium
precipitation.
Both
clarifiers
must
treat
100%
of
flow.
See
40
CFR
141.726(
b).
See
Chapter
6.

Treatment
Performance
Toolbox
Components
Combined
filter
performance
0.5
log
credit
for
combined
filter
effluent
turbidity

0.15
NTU
in
95%
of
samples
each
month.
See
40
CFR
141.727(
a).
See
Chapter
7.

Individual
filter
performance
1.0
log
credit
for
individual
filter
effluent
turbidity

0.1
NTU
in
95%
of
daily
maximum
samples
each
month
(
excluding
15
minutes
following
backwash)
and
no
filter
>
0.3
NTU
in
two
consecutive
measurements
taken
15
minutes
apart.
See
40
CFR
141.727(
b).
See
Chapter
7.

Demonstration
of
performance
Credit
based
on
a
demonstration
to
the
State
through
State­
approved
protocol.
See
40
CFR
141.727(
c).
See
Chapter
12.

Additional
Filtration
Toolbox
Components
Bag
filters
1
log
credit
with
demonstration
of
at
least
2
log
removal
efficiency
in
challenge
test;
Specific
criteria
are
in
40
CFR
141.728(
a).
See
Chapter
8.

Cartridge
filters
2
log
credit
with
demonstration
of
at
least
3
log
removal
efficiency
in
challenge
test;
Specific
criteria
are
in
40
CFR
141.728(
a).
See
Chapter
8.

Membrane
filtration
Log
removal
credit
up
to
the
lower
value
of
the
removal
efficiency
demonstrated
during
the
challenge
test
if
verified
by
direct
integrity
testing.
See
40
CFR
141.728(
b).
See
the
Guidance
Manual
for
Membrane
Filtration.

Second
stage
filtration
0.5
log
credit
for
a
second
separate
filtration
stage;
treatment
train
must
include
coagulation
prior
to
first
filter.
No
presumptive
credit
for
roughing
filters.
See
40
CFR
141.728(
c).
See
Chapter
9.

Slow
sand
filters
2.5
log
credit
for
second
separate
filtration
process.
No
disinfectant
residiual
present
in
influent.
See
40
CFR
141.728(
d).
See
Chapter
9.

Inactivation
Toolbox
Components
Chlorine
dioxide
Log
credit
based
on
demonstration
of
compliance
with
CT
tables.
See
40
CFR
141.729(
b).
See
Chapter
10.

Ozone
Log
credit
based
on
demonstration
of
compliance
with
CT
tables.
See
40
CFR
141.729(
c).
See
Chapter
11.
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
13
UV
Log
credit
based
on
demonstration
of
compliance
with
UV
dose
table;
reactor
testing
required
to
establish
validated
operating
conditions.
See
40
CFR
141.729(
d).
See
UV
Guidance
Manual.

1.6
Disinfection
Profiling
and
Benchmarking
The
purpose
of
a
disinfection
benchmark
is
to
ensure
that
when
a
system
makes
a
change
to
its
disinfection
processes,
it
does
not
compromise
the
adequacy
of
existing
microbial
protection.
A
disinfection
profile
is
a
graphical
representation
of
a
system's
level
of
Giardia
lamblia
and
viral
inactivation
measured
during
the
course
of
1
or
more
year(
s).
A
benchmark
is
the
lowest
monthly
average
of
microbial
inactivation
during
the
disinfection
profile
period.
This
tool
was
introduced
in
the
IESWTR
(
63
FR
69478
December
16,
1998)
as
a
means
for
ensuring
maintenance
of
microbial
protection
when
systems
made
changes
to
address
DBP
control
for
the
Stage
1
DBPR.
The
LT2ESWTR
also
includes
a
disinfection
benchmark
to
ensure
that
any
significant
treatment
change,
whether
for
byproduct
control
under
the
Stage
2
DBPR,
improved
Cryptosporidium
control
under
the
LT2ESWTR,
or
both,
does
not
significantly
compromise
existing
Giardia
and
virus
protection.

The
profiling
and
benchmarking
requirements
under
the
LT2ESWTR
are
similar
to
those
promulgated
under
IESWTR
and
LT1ESWTR
and
are
applicable
to:
1)
systems
required
to
conduct
Cryptosporidium
source
water
monitoring
and
2)
small
surface
water
systems
that
do
not
have
to
conduct
Cryptosporidium
source
water
monitoring
and
have
Stage
1
DBPR
TTHM
annual
average
results
of
at
least
56

g/
L
or
HAA5
annual
average
results
of
at
least
42

g/
L
(
40
CFR
141.711).
Figure
1.1
presents
a
flow
chart
that
can
be
used
to
determine
if
a
system
must
develop
a
disinfection
profile
and
benchmark.
The
LT2ESWTR
requires
these
systems
to
prepare
a
disinfection
profile
that
characterizes
current
levels
of
Giardia
lamblia
and
virus
inactivation
throughout
the
plant
over
the
course
of
one
year
(
40
CFR
141.713).
The
profile
may
be
developed
using
equivalent
historical
data.
Subsequently,
if
a
system
proposes
to
make
a
significant
change
to
its
disinfection
practice,
then
the
LT2ESWTR
requires
the
system
to
calculate
a
disinfection
benchmark
and
consult
with
the
State
regarding
how
the
proposed
change
will
affect
that
benchmark
(
40
CFR
141.714).

Detailed
guidance
for
conducting
a
disinfection
profile
and
calculating
a
benchmark
is
provided
in
the
IESWTR
Disinfection
Profiling
and
Benchmarking
Guidance
Manual
for
systems
serving
at
least
10,000
people
and
the
LT1ESWTR
Disinfection
Profiling
and
Benchmarking
Guidance
Manual
for
systems
serving
less
than
10,000
people.
A
summary
of
the
steps
required
to
create
a
disinfection
profile
and
calculate
a
benchmark
are
listed
in
the
following
two
subsections.
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
14
Does
system
serve
 
10,000
people?
Yes
No
Yes
No
Yes
No
Perform
disinfection
profiling
starting
at
42
months
after
promulgation
Perform
disinfection
profiling
starting
at
24
months
after
promulgation
Perform
disinfection
profiling
starting
at
54
months
after
promulgation
No
Calculate
disinfection
benchmark
for
both
Giardia
and
viruses
No
No
disinfection
profile
required
Does
system
provide
filtration?

Yes
No
Is
system's
TTHM
 
0.056
mg/
L
or
HAA5
 
0.042
mg/
L?
Is
system's
E.
coli
 
10/
100
mL
(
for
reservoirs/
lakes)
or
 
50/
100
mL
(
for
flowing
stream)?
Crypto
M
onitoring
Triggers
Does
system
provide
at
least
5.5
log
treatment
for
Crypto?
Yes
Yes
Does
system
have
equivalent
historical
disinfection
profile
data?
Is
system
a
NTNCWS
or
CWS?

Yes
No
Is
system
planning
a
significant
change
in
disinfection?
Yes
No
further
action
required
No
Figure
1.1
Systems
Required
to
Develop
a
Disinfection
Profile
and
Benchmark
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
15
1.6.1
Creating
a
Disinfection
Profile
The
following
steps
describe
how
to
calculate
the
Giardia
lamblia
and
virus
inactivations
over
a
one
year
period:

2)
Collect
disinfectant
residual,
temperature,
and
pH
(
if
chlorine
is
used)
data
daily
for
large
systems
and
weekly
for
small
systems
for
12
consecutive
months.
The
data
should
be
collected
after
injection
of
the
disinfectant
and
prior
to
the
first
customer
(
or
next
disinfectant
injection
point
if
applicable)
during
peak
hourly
flow.

2)
Determine
disinfectant
contact
time
during
peak
hourly
flow
conditions
measured
between
the
point
of
application
and
the
point
of
residual
measurement.

3)
Calculate
CT
calc
(
product
of
disinfectant
residual
concentration
and
contact
time)
and
from
the
CT
tables
determine
the
CT
99.9,
Giardia
and
CT
99.99,
virus.
(
Chapter
12
contains
more
detailed
information
on
calculating
CT.)

4)
Calculate
the
estimated
log
inactivation
for
Giardia
and
viruses
according
to
the
following
equations:

Log
inactivation
of
Giardia
=
3.0
×
CT
calc
/
CT
99.9,
Giardia
Log
inactivation
of
viruses
=
4.0
×
CT
calc
/
CT
99.99,
virus
5)
Plot
the
total
log
inactivations
from
each
day
or
week
on
a
graph
(
Giardia
and
virus
data
on
separate
graphs).
The
resulting
graph
of
365
days
or
52
weeks
of
data
is
the
disinfection
profile.

1.6.2
Disinfection
Benchmark
A
system
that
is
required
to
develop
a
disinfection
profile
and
that
plans
to
make
a
significant
change
to
its
disinfection
practice
must
calculate
a
benchmark
and
notify
the
State
prior
to
making
the
change
(
40
CFR
141.714(
a)).
The
LT2ESWTR
defines
significant
changes
to
disinfection
practices
as
changing
the
point
of
disinfection,
the
type
of
disinfectant,
the
process
used,
or
other
changes
identified
by
the
State.

The
benchmark
is
a
system's
lowest
monthly
average
microbial
inactivation
based
on
the
disinfection
profile.
If
the
benchmark
is
substantially
greater
than
the
required
inactivation
(
3.0
log
Giardia
and
4.0
log
virus),
then
a
system
may
consider
decreasing
the
amount
of
disinfectant
added,
contact
time,
or
altering
other
disinfection
practices,
as
long
as
it
notifies
the
State.
Chapter
1
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
16
1.7
Implementation
Schedule
For
those
systems
requiring
additional
treatment,
the
LT2ESWTR
requires
compliance
by
[
72
months
after
promulgation]
for
systems
serving
10,000
or
more
people
and
[
102
months
after
promulgation]
for
systems
serving
less
than
10,000
people
(
40
CFR
141.701(
e)).
States
may
grant
an
extra
two
years
to
systems
that
need
to
make
capital
improvements
in
order
to
meet
the
requirements.
However,
some
toolbox
options
have
additional
requirements
that
must
be
met
at
an
earlier
date.
Table
1.4
lists
the
requirements
and
compliance
dates
for
each
toolbox
option
for
large
and
small
systems,
respectively.
Chapter
1.0
­
Introduction
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
17
Table
1.4
Compliance
Dates1
Toolbox
Option
Systems
must
submit
the
following
information
Schedule
Systems
serving
>
10,000
people
Systems
serving
<
10,000
people
Watershed
Control
Program
(
WCP)
Notify
State
of
intention
to
develop
WCP
No
later
than
[
date
48
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
No
later
than
[
date
78
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Submit
initial
WCP
plan
to
State
No
later
than
[
date
60
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
No
later
than
[
date
90
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Annual
report
and
State­
approved
watershed
survey
report
By
a
date
determined
by
the
State,
every
12
months,

beginning
on
[
date
84
months
after
date
of
publication
of
final
rule
in
the
Federal
Register].
By
a
date
determined
by
the
State,
every
12
months,

beginning
on
[
date
114
months
after
date
of
publication
of
final
rule
in
the
Federal
Register].

Request
for
re­
approval
and
report
on
the
previous
approval
period.
Six
months
prior
to
the
end
of
the
current
approval
period
or
by
a
date
previously
determined
by
the
State.
Six
months
prior
to
the
end
of
the
current
approval
period
or
by
a
date
previously
determined
by
the
State.

Presedimentation
(
new
basins)
Monthly
verification
of:

Continuous
basin
operation

Treatment
of
100%
of
the
flow

Continuous
addition
of
a
coagulant

At
least
0.5
log
removal
of
influent
turbidity
based
on
the
monthly
mean
of
daily
turbidity
readings
for
11
of
the
12
previous
months
Within
10
days
following
each
month
in
which
the
monitoring
was
conducted,
beginning
on
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
each
month
in
which
the
monitoring
was
conducted,
beginning
on
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Chapter
1.0
­
Introduction
Toolbox
Option
Systems
must
submit
the
following
information
Schedule
Systems
serving
>
10,000
people
Systems
serving
<
10,000
people
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
18
Bank
filtration
Initial
demonstration
of

Unconsolidated,
predominantly
sandy
aquifer

Setback
distance
of
at
least
25
ft.
(
0.5
log)
or
50
ft.
(
1.0
log)
Initial
demonstration
no
later
than
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Initial
demonstration
no
later
than
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

If
monthly
average
of
daily
max
turbidity
is
greater
than
1
NTU,
then
system
must
report
result
and
submit
an
assessment
of
the
cause
Report
within
30
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Report
within
30
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Two­
stage
lime
softening
Monthly
verification
of:

Continuous
operation
of
a
second
clarification
step
between
the
primary
clarifier
and
filter

Continuous
presence
of
a
coagulant
in
both
primary
and
secondary
clarifiers

Both
clarifiers
treat
100%
of
the
plant
flow
Within
10
days
following
each
month
in
which
the
monitoring
was
conducted,
beginning
on
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
each
month
in
which
the
monitoring
was
conducted,
beginning
on
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Combined
filter
performance
Monthly
verification
of:

Combined
filter
effluent
(
CFE)
turbidity
levels
less
than
or
equal
to
0.15
NTU
in
at
least
95
percent
of
the
4
hour
CFE
measurements
taken
each
month
Within
10
days
following
each
month
in
which
the
monitoring
was
conducted,
beginning
on
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
each
month
in
which
the
monitoring
was
conducted,
beginning
on
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Individual
filter
performance
Monthly
verification
of:

Individual
filter
effluent
(
IFE
)
turbidity
levels
less
than
or
equal
to
0.1
NTU
in
at
least
95
percent
of
all
IFE
measurements
taken
each
month
based
on
daily
maximum
(
excluding
15
min
period
following
start­
up
after
backwash)

No
individual
filter
greater
than
0.3
NTU
in
two
consecutive
readings
15
minutes
apart
Within
10
days
following
each
month
in
which
the
monitoring
was
conducted,
beginning
on
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
each
month
in
which
the
monitoring
was
conducted,
beginning
on
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Chapter
1.0
­
Introduction
Toolbox
Option
Systems
must
submit
the
following
information
Schedule
Systems
serving
>
10,000
people
Systems
serving
<
10,000
people
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
19
Membrane
filtration
Results
of
verification
testing
demonstrating:

Removal
efficiency
established
through
challenge
testing
that
meets
rule
criteria

Integrity
testing
and
associated
baseline
No
later
than
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
No
later
than
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Monthly
report
summarizing
any
direct
integrity
tests
above
the
control
limit,
any
indirect
integrity
monitoring
results
triggering
direct
integrity
testing
and
the
corrective
action
that
was
taken.
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Bag
filters
and
cartridge
filters
Demonstration
that
the
following
criteria
are
met:

Process
meets
the
definition
of
bag
or
cartridge
filtration

Removal
efficiency
established
through
challenge
testing
that
meets
rule
criteria

Challenge
test
shows
at
least
2
log
removal
for
bag
filters
and
3
log
removal
for
cartridge
filters
No
later
than
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
No
later
than
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Monthly
verification
that
100%
of
flow
was
filtered.
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Second
stage
filtration
Monthly
verification
that
100%
of
flow
was
filtered.
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Chapter
1.0
­
Introduction
Toolbox
Option
Systems
must
submit
the
following
information
Schedule
Systems
serving
>
10,000
people
Systems
serving
<
10,000
people
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
20
Slow
sand
filtration
Monthly
verification
that
100%
of
flow
was
filtered.
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Chlorine
dioxide
Summary
of
CT
values
for
each
day
based
on
Tables
in
40
CFR
141.729(
b).
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Ozone
Summary
of
CT
values
for
each
day
based
on
Tables
in
40
CFR
141.729(
c).
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

UV
Validation
test
results
demonstrating
operating
conditions
that
achieve
required
UV
dose.
No
later
than
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
No
later
than
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

Monthly
report
summarizing
the
percentage
of
water
entering
the
distribution
system
that
was
not
treated
by
UV
reactors
operating
within
validated
conditions.
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Toolbox
Option
Systems
must
submit
the
following
information
Schedule
Systems
serving
>
10,000
people
Systems
serving
<
10,000
people
LT2ESWTR
Toolbox
Guidance
Manual
Proposal
Draft
June
2003
1­
21
Demonstration
of
Performance
Results
from
testing
following
a
State
approved
protocol.
No
later
than
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
No
later
than
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

As
required
by
the
State,
monthly
verification
of
operating
within
conditions
of
State
approval
for
demonstration
of
performance
credit.
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
72
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]
Within
10
days
following
the
month
in
which
monitoring
was
conducted,
beginning
[
date
102
months
after
date
of
publication
of
final
rule
in
the
Federal
Register]

1(
40
CFR
141.730)