Glossary
of
Terms
This
glossary
includes
a
collection
of
the
terms
used
in
this
manual
and
an
explanation
of
each
term.
To
the
extent
that
definitions
and
explanations
provided
in
this
glossary
differ
from
those
in
EPA
regulations
or
other
official
documents,
they
are
intended
for
use
in
understanding
this
manual
only.

°
401(
a)
Certification
 
A
requirement
of
Section
401(
a)
of
the
Clean
Water
Act
that
all
federally
issued
permits
be
certified
by
the
State
in
which
the
discharge
occurs.
The
State
certifies
that
the
proposed
permit
will
comply
with
State
water
quality
standards
and
other
State
requirements.

°
Acute
 
A
stimulus
severe
enough
to
rapidly
induce
an
effect;
in
aquatic
toxicity
tests,
an
effect
observed
in
96
hours
or
less
is
typically
considered
acute.
When
referring
to
aquatic
toxicology
or
human
health,
an
acute
effect
is
not
always
measured
in
terms
of
lethality.

°
Anti­
backsliding
 
A
provision
in
the
Federal
Regulations
[
CWA
§
303(
d)(
4);
CWA
§
402(
c);
CFR
§
122.44(
l)]
that
requires
a
reissued
permit
to
be
as
stringent
as
the
previous
permit
with
some
exceptions.

°
Antidegradation
 
Policies
which
ensure
protection
of
water
quality
for
a
particular
water
body
where
the
water
quality
exceeds
levels
necessary
to
protect
fish
and
wildlife
propagation
and
recreation
on
and
in
the
water.
This
also
includes
special
protection
of
waters
designated
as
outstanding
natural
resource
waters.
Antidegradation
plans
are
adopted
by
each
State
to
minimize
adverse
effects
on
water.

°
Authorized
Program
or
Authorized
State
 
A
State,
Territorial,
Tribal,
or
interstate
NPDES
program
which
has
been
approved
or
authorized
by
EPA
under
40
CFR
Part
123.

°
Average
Monthly
Discharge
Limitations
 
The
highest
allowable
average
of
daily
discharges
over
a
calendar
month,
calculated
as
the
sum
of
all
daily
discharges
measured
during
that
month
divided
by
the
number
of
days
on
which
monitoring
was
performed
(
except
in
the
case
of
fecal
coliform).

°
Average
Weekly
Discharge
Limitation
 
The
highest
allowable
average
of
daily
discharges
over
a
calendar
week,
calculated
as
the
sum
of
all
daily
discharges
measured
during
a
calendar
week
divided
by
the
number
of
daily
discharges
measured
during
that
week.

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Glossary
of
Terms
°
Best
Available
Technology
Economically
Achievable
(
BAT)
 
Technology­
based
standard
established
by
the
Clean
Water
Act
(
CWA)
as
the
most
appropriate
means
available
on
a
national
basis
for
controlling
the
direct
discharge
of
toxic
and
nonconventional
pollutants
to
navigable
waters.
BAT
effluent
limitations
guidelines,
in
general,
represent
the
best
existing
performance
of
treatment
technologies
that
are
economically
achievable
within
an
industrial
point
source
category
or
subcategory.

°
Best
Conventional
Pollutant
Control
Technology
(
BCT)
 
Technologybased
standard
for
the
discharge
from
existing
industrial
point
sources
of
conventional
pollutants
including
BOD,
TSS,
fecal
coliform,
pH,
oil
and
grease.
The
BCT
is
established
in
light
of
a
two­
part
"
cost
reasonableness"
test
which
compares
the
cost
for
an
industry
to
reduce
its
pollutant
discharge
with
the
cost
to
a
POTW
for
similar
levels
of
reduction
of
a
pollutant
loading.
The
second
test
examines
the
cost­
effectiveness
of
additional
industrial
treatment
beyond
BPT.
EPA
must
find
limits
which
are
reasonable
under
both
tests
before
establishing
them
as
BCT.

°
Best
Management
Practice
(
BMP)
 
Permit
condition
used
in
place
of
or
in
conjunction
with
effluent
limitations
to
prevent
or
control
the
discharge
of
pollutants.
May
include
schedule
of
activities,
prohibition
of
practices,
maintenance
procedure,
or
other
management
practice.
BMPs
may
include,
but
are
not
limited
to,
treatment
requirements,
operating
procedures,
or
practices
to
control
plant
site
runoff,
spillage,
leaks,
sludge
or
waste
disposal,
or
drainage
from
raw
material
storage.

°
Best
Practicable
Control
Technology
Currently
Available
(
BPT)
 
The
first
level
of
technology­
based
standards
established
by
the
CWA
to
control
pollutants
discharged
to
waters
of
the
U.
S.
BPT
effluent
limitations
guidelines
are
generally
based
on
the
average
of
the
best
existing
performance
by
plants
within
an
industrial
category
or
subcategory.

°
Best
Professional
Judgment
(
BPJ)
 
The
method
used
by
permit
writers
to
develop
technology­
based
NPDES
permit
conditions
on
a
case­
by­
case
basis
using
all
reasonably
available
and
relevant
data.

°
Bioassay
 
A
test
used
to
evaluate
the
relative
potency
of
a
chemical
or
a
mixture
of
chemicals
by
comparing
its
effect
on
a
living
organism
with
the
effect
of
a
standard
preparation
on
the
same
type
of
organism.

°
Biochemical
Oxygen
Demand
(
BOD)
 
A
measurement
of
the
amount
of
oxygen
utilized
by
the
decomposition
of
organic
material,
over
a
specified
time
period
(
usually
5
days)
in
a
wastewater
sample;
it
is
used
as
a
measurement
of
the
readily
decomposable
organic
content
of
a
wastewater.

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Permit
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Glossary
of
Terms
°
Bypass
 
The
intentional
diversion
of
wastestreams
from
any
portion
of
a
treatment
(
or
pretreatment)
facility.

°
Categorical
Industrial
User
(
CIU)
 
An
industrial
user
subject
to
National
categorical
pretreatment
standards.

°
Categorical
Pretreatment
Standards
 
Limitations
on
pollutant
discharges
to
publicly
owned
treatment
works
promulgated
by
EPA
in
accordance
with
Section
307
of
the
Clean
Water
Act
that
apply
to
specified
process
wastewaters
of
particular
industrial
categories
[
40
CFR
§
403.6
and
Parts
405­
471].

°
Chemical
Oxygen
Demand
(
COD)
 
A
measure
of
the
oxygen­
consuming
capacity
of
inorganic
and
organic
matter
present
in
wastewater.
COD
is
expressed
as
the
amount
of
oxygen
consumed
in
mg/
l.
Results
do
not
necessarily
correlate
to
the
biochemical
oxygen
demand
(
BOD)
because
the
chemical
oxidant
may
react
with
substances
that
bacteria
do
not
stabilize.

°
Chronic
 
A
stimulus
that
lingers
or
continues
for
a
relatively
long
period
of
time,
often
one­
tenth
of
the
life
span
or
more.
Chronic
should
be
considered
a
relative
term
depending
on
the
life
span
of
an
organism.
The
measurement
of
a
chronic
effect
can
be
reduced
growth,
reduced
reproduction,
etc.,
in
addition
to
lethality.

°
Clean
Water
Act
(
CWA)
 
The
Clean
Water
Act
is
an
act
passed
by
the
U.
S.
Congress
to
control
water
pollution.
It
was
formerly
referred
to
as
the
Federal
Water
Pollution
Control
Act
of
1972
or
Federal
Water
Pollution
Control
Act
Amendments
of
1972
(
Public
Law
92­
500),
33
U.
S.
C.
1251
et.
seq.,
as
amended
by:
Public
Law
96­
483;
Public
Law
97­
117;
Public
Laws
95­
217,
97­
117,
97­
440,
and
100­
04.

°
Code
of
Federal
Regulations
(
CFR)
 
A
codification
of
the
final
rules
published
daily
in
the
Federal
Register.
Title
40
of
the
CFR
contains
the
environmental
regulations.

°
Combined
Sewer
Overflow
(
CSO)
 
A
discharge
of
untreated
wastewater
from
a
combined
sewer
system
at
a
point
prior
to
the
headworks
of
a
publicly
owned
treatment
works.
CSOs
generally
occur
during
wet
weather
(
rainfall
or
snowmelt).
During
periods
of
wet
weather,
these
systems
become
overloaded,
bypass
treatment
works,
and
discharge
directly
to
receiving
waters.

NPDES
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Glossary
of
Terms
°
Combined
Sewer
System
(
CSS)
 
A
wastewater
collection
system
which
conveys
sanitary
wastewaters
(
domestic,
commercial
and
industrial
wastewaters)
and
storm
water
through
a
single
pipe
to
a
publicly
owned
treatment
works
for
treatment
prior
to
discharge
to
surface
waters.

°
Compliance
Schedule
 
A
schedule
of
remedial
measures
included
in
a
permit
or
an
enforcement
order,
including
a
sequence
of
interim
requirements
(
for
example,
actions,
operations,
or
milestone
events)
that
lead
to
compliance
with
the
CWA
and
regulations.

°
Composite
Sample
 
Sample
composed
of
two
or
more
discrete
samples.
The
aggregate
sample
will
reflect
the
average
water
quality
covering
the
compositing
or
sample
period.

°
Conventional
Pollutants
 
Pollutants
typical
of
municipal
sewage,
and
for
which
municipal
secondary
treatment
plants
are
typically
designed;
defined
by
Federal
Regulation
[
40
CFR
§
401.16]
as
BOD,
TSS,
fecal
coliform
bacteria,
oil
and
grease,
and
pH.

°
Criteria
 
The
numeric
values
and
the
narrative
standards
that
represent
contaminant
concentrations
that
are
not
to
be
exceeded
in
the
receiving
environmental
media
(
surface
water,
ground
water,
sediment)
to
protect
beneficial
uses.

°
Daily
Discharge
 
The
discharge
of
a
pollutant
measured
during
any
24­
hour
period
that
reasonably
represents
a
calendar
day
for
purposes
of
sampling.
For
pollutants
with
limitations
expressed
in
units
of
mass,
the
daily
discharge
is
calculated
as
the
total
mass
of
the
pollutant
discharged
during
the
day.
For
pollutants
with
limitations
expressed
in
other
units
of
measurement
(
e.
g.,
concentration)
the
daily
discharge
is
calculated
as
the
average
measurement
of
the
pollutant
throughout
the
day
(
40
CFR
§
122.2).

°
Daily
Maximum
Limit
 
The
maximum
allowable
discharge
of
pollutant
during
a
calendar
day.
Where
daily
maximum
limitations
are
expressed
in
units
of
mass,
the
daily
discharge
is
the
total
mass
discharged
over
the
course
of
the
day.
Where
daily
maximum
limitations
are
expressed
in
terms
of
a
concentration,
the
daily
discharge
is
the
arithmetic
average
measurement
of
the
pollutant
concentration
derived
from
all
measurements
taken
that
day.

°
Development
Document
 
A
report
prepared
during
the
development
of
an
effluent
limitation
guideline
by
EPA
that
provides
the
data
and
methodology
used
to
develop
limitations
guidelines
and
categorical
pretreatment
standards
for
an
industrial
category.

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Glossary
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°
Director
 
The
Regional
Administrator
or
State
Director,
as
the
context
requires,
or
an
authorized
representative.
When
there
is
no
approved
State
program,
and
there
is
an
EPA
administered
program,
Director
means
the
Regional
Administrator.
When
there
is
an
approved
State
program,
"
Director"
normally
means
the
State
Director.

°
Discharge
Monitoring
Report
(
DMR)
 
The
form
used
(
including
any
subsequent
additions,
revisions,
or
modifications)
to
report
self­
monitoring
results
by
NPDES
permittees.
DMRs
must
be
used
by
approved
States
as
well
as
by
EPA.

°
Draft
Permit
 
A
document
prepared
under
40
CFR
§
124.6
indicating
the
Director's
tentative
decision
to
issue,
deny,
modify,
revoke
and
reissue,
terminate,
or
reissue
a
permit.
A
notice
of
intent
to
terminate
a
permit,
and
a
notice
of
intent
to
deny
a
permit
application,
as
discussed
in
40
CFR
§
124.5,
are
considered
draft
permits.
A
denial
of
a
request
for
modification,
revocation
and
reissuance,
or
termination,
as
discussed
in
40
CFR
§
124.5,
is
not
a
draft
permit.

°
Effluent
Limitation
 
Any
restriction
imposed
by
the
Director
on
quantities,
discharge
rates,
and
concentrations
of
pollutants
which
are
discharged
from
point
sources
into
waters
of
the
United
States,
the
waters
of
the
contiguous
zone,
or
the
ocean.

°
Effluent
Limitations
Guidelines
(
ELG)
 
A
regulation
published
by
the
Administrator
under
Section
304(
b)
of
CWA
that
establishes
national
technology­
based
effluent
requirements
for
a
specific
industrial
category.

°
Fact
Sheet
 
A
document
that
must
be
prepared
for
all
draft
individual
permits
for
NPDES
major
dischargers,
NPDES
general
permits,
NPDES
permits
that
contain
variances,
NPDES
permits
that
contain
sewage
sludge
land
application
plans
and
several
other
classes
of
permittees.
The
document
summarizes
the
principal
facts
and
the
significant
factual,
legal,
methodological
and
policy
questions
considered
in
preparing
the
draft
permit
and
tells
how
the
public
may
comment
(
40
CFR
§
124.8
and
§
124.56).
Where
a
fact
sheet
is
not
required,
a
statement
of
basis
must
be
prepared
(
40
CFR
§
124.7).

°
Fundamentally
Different
Factors
(
FDF)
 
Those
components
of
a
petitioner's
facility
that
are
determined
to
be
so
unlike
those
components
considered
by
EPA
during
the
effluent
limitation
guideline
and
pretreatment
standards
rulemaking
that
the
facility
is
worthy
of
a
variance
from
the
effluent
limitations
guidelines
or
categorical
pretreatment
standards.

°
General
Permit
 
An
NPDES
permit
issued
under
40
CFR
§
122.28
that
authorizes
a
category
of
discharges
under
the
CWA
within
a
geographical
NPDES
Permit
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Training
Manual
­
G­
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Glossary
of
Terms
area.
A
general
permit
is
not
specifically
tailored
for
an
individual
discharger.

°
Grab
Sample
 
A
sample
which
is
taken
from
a
wastestream
on
a
one­
time
basis
without
consideration
of
the
flow
rate
of
the
wastestream
and
without
consideration
of
time.

°
Hazardous
Substance
 
Any
substance,
other
than
oil,
which,
when
discharged
in
any
quantities
into
waters
of
the
U.
S.,
presents
an
imminent
and
substantial
danger
to
the
public
health
or
welfare,
including
but
not
limited
to
fish,
shellfish,
wildlife,
shorelines
and
beaches
(
Section
311
of
the
CWA);
identified
by
EPA
as
the
pollutants
listed
under
40
CFR
Part
116.

°
Indirect
Discharge
 
The
introduction
of
pollutants
into
a
municipal
sewage
treatment
system
from
any
nondomestic
source
(
i.
e.,
any
industrial
or
commercial
facility)
regulated
under
Section
307(
b),
(
c),
or
(
d)
of
the
CWA.

°
Instantaneous
Maximum
Limit
 
The
maximum
allowable
concentration
of
a
pollutant
determined
from
the
analysis
of
any
discrete
or
composite
sample
collected,
independent
of
the
flow
rate
and
the
duration
of
the
sampling
event.

°
Local
Limits
 
Conditional
discharge
limits
imposed
by
municipalities
upon
industrial
or
commercial
facilities
that
discharge
to
the
municipal
sewage
treatment
system.

°
Major
Facility
 
Any
NPDES
facility
or
activity
classified
as
such
by
the
Regional
Administrator,
or
in
the
case
of
approved
State
programs,
the
Regional
Administrator
in
conjunction
with
the
State
Director.
Major
municipal
dischargers
include
all
facilities
with
design
flows
of
greater
than
one
million
gallons
per
day
and
facilities
with
EPA/
State
approved
industrial
pretreatment
programs.
Major
industrial
facilities
are
determined
based
on
specific
ratings
criteria
developed
by
EPA/
State.

°
Mass­
Based
Standard
 
A
discharge
limit
that
is
measured
in
a
mass
unit
such
as
pounds
per
day.

°
Method
Detection
Limit
(
MDL)­
Defined
as
the
minimum
concentration
of
a
substance
that
can
be
measured
and
reported
with
99
percent
confidence
that
the
analyte
concentration
is
greater
than
zero
and
is
determined
from
analysis
of
a
sample
in
a
given
matrix
containing
the
analyte.

°
Million
Gallons
per
Day
(
mgd)
 
A
unit
of
flow
commonly
used
for
wastewater
discharges.
One
mgd
is
equivalent
to
1.547
cubic
feet
per
second.

G­
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Glossary
of
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°
Mixing
Zone
 
An
area
where
an
effluent
discharge
undergoes
initial
dilution
and
is
extended
to
cover
the
secondary
mixing
in
the
ambient
water
body.
A
mixing
zone
is
an
allocated
impact
zone
where
water
quality
criteria
can
be
exceeded
as
long
as
acutely
toxic
conditions
are
prevented.

°
Municipal
Separate
Storm
Sewer
System
(
MS4)
 
A
conveyance
or
system
of
conveyances
(
including
roads
with
drainage
systems,
municipal
streets,
catch
basins,
curbs,
gutters,
ditches,
manmade
channels,
or
storm
drains)
owned
by
a
State,
city,
town
or
other
public
body,
that
is
designed
or
used
for
collecting
or
conveying
storm
water,
which
is
not
a
combined
sewer,
and
which
is
not
part
of
a
publicly
owned
treatment
works.
Commonly
referred
to
as
an
"
MS4"
[
40
CFR
§
122.26(
b)(
8)].

°
National
Pollutant
Discharge
Elimination
System
(
NPDES)
 
The
national
program
for
issuing,
modifying,
revoking
and
reissuing,
terminating,
monitoring
and
enforcing
permits,
and
imposing
and
enforcing
pretreatment
requirements,
under
Sections
307,
318,
402,
and
405
of
CWA.

°
National
Pretreatment
Standard
or
Pretreatment
Standard
 
Any
regulation
promulgated
by
the
EPA
in
accordance
with
Sections
307(
b)
and
(
c)
of
the
CWA
that
applies
to
a
specific
category
of
industrial
users
and
provides
limitations
on
the
introduction
of
pollutants
into
publicly
owned
treatment
works.
This
term
includes
the
prohibited
discharge
standards
under
40
CFR
§
403.5,
including
local
limits
[
40
CFR
§
403.3(
j)].

°
New
Discharger
 
Any
building,
structure,
facility,
or
installation:

a.
From
which
there
is
or
may
be
a
discharge
of
pollutants;

b.
That
did
not
commence
the
discharge
of
pollutants
at
that
particular
site
prior
to
August
13,
1979;

c.
Which
is
not
a
new
source;
and
d.
Which
has
never
received
a
finally
effective
NPDES
permit
for
discharges
at
that
site.

°
New
Source
 
Any
building,
structure,
facility,
or
installation
from
which
there
is
or
may
be
a
discharge
of
pollutants,
the
construction
of
which
commenced:

a.
After
promulgation
of
standards
of
performance
under
Section
306
of
the
CWA
which
are
applicable
to
such
source;
or
NPDES
Permit
Writer
Training
Manual
­
G­
7
Glossary
of
Terms
b.
After
proposal
of
standards
of
performance
in
accordance
with
Section
306
of
the
CWA
which
are
applicable
to
such
source,
but
only
if
the
standards
are
promulgated
in
accordance
with
Section
306
of
the
CWA
within
120
days
of
their
proposal.

c.
Except
as
otherwise
provided
in
an
applicable
new
source
performance
standard,
a
source
is
a
new
source
if
it
meets
the
definition
in
40
CFR
§
122.2;
and
i.
It
is
constructed
at
a
site
at
which
no
other
source
is
located;
or
ii.
It
totally
replaces
the
process
or
production
equipment
that
causes
the
discharge
of
pollutants
at
an
existing
source;
or
iii.
Its
processes
are
substantially
independent
of
an
existing
source
at
the
same
site.
In
determining
whether
these
processes
are
substantially
independent,
the
Director
shall
consider
such
factors
as
the
extent
to
which
the
new
facility
is
integrated
with
the
existing
plant;
and
the
extent
to
which
the
new
facility
is
engaged
in
the
same
general
type
of
activity
as
the
existing
source.

°
New
Source
Performance
Standards
(
NSPS)
 
Technology­
based
standards
for
facilities
that
qualify
as
new
sources
under
40
CFR
§
122.2
and
40
CFR
§
122.29.
Standards
consider
that
the
new
source
facility
has
an
opportunity
to
design
operations
to
more
effectively
control
pollutant
discharges.

°
Nonconventional
Pollutants
 
All
pollutants
that
are
not
included
in
the
list
of
conventional
or
toxic
pollutants
in
40
CFR
Part
401.
Includes
pollutants
such
as
chemical
oxygen
demand
(
COD),
total
organic
carbon
(
TOC),
nitrogen,
and
phosphorus.

°
pH
 
A
measure
of
the
hydrogen
ion
concentration
of
water
or
wastewater;
expressed
as
the
negative
log
of
the
hydrogen
ion
concentration
in
mg/
l.
A
pH
of
7
is
neutral.
A
pH
less
than
7
is
acidic,
and
a
pH
greater
than
7
is
basic.

°
Point
Source
 
Any
discernible,
confined,
and
discrete
conveyance,
including
but
not
limited
to
any
pipe,
ditch,
channel,
tunnel,
conduit,
well,
discrete
fixture,
container,
rolling
stock,
concentrated
animal
feeding
operation,
landfill
leachate
collection
system,
vessel,
or
other
floating
craft
from
which
pollutants
are
or
may
be
discharged.

G­
8
­
NPDES
Permit
Writer
Training
Manual
Glossary
of
Terms
°
Pollutant
 
Dredged
spoil,
solid
waste,
incinerator
residue,
filter
backwash,
sewage,
garbage,
sewage
sludge,
munitions,
chemical
wastes,
biological
materials,
radioactive
materials
(
except
those
regulated
under
the
Atomic
Energy
Act
of
1954,
as
amended
(
42
U.
S.
C.
2011
et
seq.)),
heat,
wrecked
or
discarded
equipment,
rock,
sand,
cellar
dirt
and
industrial,
municipal,
and
agricultural
waste
discharged
into
water.

°
Pollutant,
Conservative
 
Pollutants
that
do
not
readily
degrade
in
the
environment,
and
which
are
mitigated
primarily
by
natural
stream
dilution
after
entering
receiving
bodies
of
waters.
Included
are
pollutants
such
as
metals.

°
Pollutant,
Non­
Conservative
 
Pollutants
that
are
mitigated
by
natural
biodegradation
or
other
environmental
decay
or
removal
processes
in
the
receiving
stream
after
in­
stream
mixing
and
dilution
have
occurred.

°
Practical
Quantification
Limit
(
PQL)
 
The
lowest
level
that
can
be
reliably
achieved
within
specified
limits
of
precision
and
accuracy
during
routine
laboratory
operating
conditions.

°
Pretreatment
 
The
reduction
of
the
amount
of
pollutants,
the
elimination
of
pollutants,
or
the
alteration
of
the
nature
of
pollutant
properties
in
wastewater
prior
to
or
in
lieu
of
discharging
or
otherwise
introducing
such
pollutants
into
a
publicly
owned
treatment
works
[
40
CFR
§
403.3(
q)].

°
Primary
Industry
Categories
 
Any
industry
category
listed
in
the
Natural
Resources
Defense
Council
(
NRDC)
settlement
agreement
[(
NRDC
et
al.
v.
Train,
8
E.
R.
C.
2120
(
D.
D.
C.
1976),
modified
12
E.
R.
C.
1833
(
D.
D.
C.
1979)]
for
which
EPA
has
or
will
develop
effluent
guidelines;
also
listed
in
Appendix
A
of
40
CFR
Part
122.

°
Primary
Treatment
 
The
practice
of
removing
some
portion
of
the
suspended
solids
and
organic
matter
in
a
wastewater
through
sedimentation.
Common
usage
of
this
term
also
includes
preliminary
treatment
to
remove
wastewater
constituents
that
may
cause
maintenance
or
operational
problems
in
the
system
(
i.
e.,
grit
removal,
screening
for
rags
and
debris,
oil
and
grease
removal,
etc.).

°
Priority
Pollutants
 
Those
pollutants
considered
to
be
of
principal
importance
for
control
under
the
CWA
based
on
the
NRDC
consent
decree
settlement
[(
NRDC
et
al.
v.
Train,
8
E.
R.
C.
2120
(
D.
D.
C.
1976),
modified
12
E.
R.
C.
1833
(
D.
D.
C.
1979)];
a
list
of
these
pollutants
is
provided
as
Appendix
A
to
40
CFR
Part
423.

NPDES
Permit
Writer
Training
Manual
­
G­
9
Glossary
of
Terms
°
Process
Wastewater
 
Any
water
which,
during
manufacturing
or
processing,
comes
into
direct
contact
with,
or
results
from
the
production
or
use
of
any
raw
material,
intermediate
product,
finished
product,
byproduct,
or
waste
product.

°
Production­
Based
Standard
 
A
discharge
standard
expressed
in
terms
of
pollutant
mass
allowed
in
a
discharge
per
unit
of
product
manufactured.

°
Proposed
Permit
 
A
State
NPDES
permit
prepared
after
the
close
of
the
public
comment
period
(
and
when
applicable,
any
public
hearing
and
administrative
appeals)
which
is
sent
to
EPA
for
review
before
final
issuance
by
the
State.

°
Publicly
Owned
Treatment
Works
(
POTW)
 
A
treatment
works,
as
defined
by
Section
212
of
the
CWA,
that
is
owned
by
the
State
or
municipality.
This
definition
includes
any
devices
and
systems
used
in
the
storage,
treatment,
recycling,
and
reclamation
of
municipal
sewage
or
industrial
wastes
of
a
liquid
nature.
It
also
includes
sewers,
pipes,
and
other
conveyances
only
if
they
convey
wastewater
to
a
POTW
treatment
plant
[
40
CFR
§
403.3].

°
Sanitary
Sewer
 
A
pipe
or
conduit
(
sewer)
intended
to
carry
wastewater
or
water­
borne
wastes
from
homes,
businesses,
and
industries
to
the
POTW.

°
Sanitary
Sewer
Overflows
(
SSO)
 
Untreated
or
partially
treated
sewage
overflows
from
a
sanitary
sewer
collection
system.

°
Secondary
Industry
Category
 
Any
industry
category
which
is
not
a
primary
industry
category.

°
Secondary
Treatment
 
Technology­
based
requirements
for
direct
discharging
municipal
sewage
treatment
facilities.
Standard
is
based
on
a
combination
of
physical
and
biological
processes
typical
for
the
treatment
of
pollutants
in
municipal
sewage.
Standards
are
expressed
as
a
minimum
level
of
effluent
quality
in
terms
of:
BOD
5,
suspended
solids
(
SS),
and
pH
(
except
as
provided
for
special
considerations
and
treatment
equivalent
to
secondary
treatment).

°
Self­
Monitoring
 
Sampling
and
analyses
performed
by
a
facility
to
determine
compliance
with
a
permit
or
other
regulatory
requirements.

°
Spill
Prevention
Control
and
Countermeasure
Plan
(
SPCC)
 
A
plan
prepared
by
a
facility
to
minimize
the
likelihood
of
a
spill
and
to
expedite
control
and
cleanup
activities
should
a
spill
occur.

G­
10
­
NPDES
Permit
Writer
Training
Manual
Glossary
of
Terms
°
Significant
Industrial
User
(
SIU)
 
An
indirect
discharger
that
is
the
focus
of
control
efforts
under
the
national
pretreatment
program;
includes
all
indirect
dischargers
subject
to
national
categorical
pretreatment
standards,
and
all
other
indirect
dischargers
that
contribute
25,000
gpd
or
more
of
process
wastewater,
or
which
make
up
five
percent
or
more
of
the
hydraulic
or
organic
loading
to
the
municipal
treatment
plant,
subject
to
certain
exceptions
[
40
CFR
§
403.3(
t)].

°
Standard
Industrial
Classification
(
SIC)
Code
 
A
code
number
system
used
to
identify
various
types
of
industries.
The
code
numbers
are
published
by
the
Superintendent
of
Documents,
U.
S.
Government
Printing
Office,
Washington,
D.
C.
20402.
A
particular
industry
may
have
more
than
one
SIC
code
if
it
conducts
several
types
of
commercial
or
manufacturing
activities
onsite.

°
Statement
of
Basis
 
A
document
prepared
for
every
draft
NPDES
permit
for
which
a
fact
sheet
is
not
required.
A
statement
of
basis
briefly
describes
how
permit
conditions
were
derived
and
the
reasons
the
conditions
are
necessary
for
the
permit
[
40
CFR
§
124.7].

°
STORET
 
EPA's
computerized
STOrage
and
RETrieval
water
quality
data
base
that
includes
physical,
chemical,
and
biological
data
measured
in
waterbodies
throughout
the
United
States.

°
Storm
Water
 
Storm
water
runoff,
snow
melt
runoff,
and
surface
runoff
and
drainage
[
40
CFR
§
122.26(
b)(
13)].

°
Technology­
Based
Effluent
Limit
 
A
permit
limit
for
a
pollutant
that
is
based
on
the
capability
of
a
treatment
method
to
reduce
the
pollutant
to
a
certain
concentration.

°
Tiered
Permit
Limits
 
Permit
limits
that
only
apply
to
the
discharge
when
a
certain
threshold
(
e.
g.,
production
level),
specific
circumstance
(
e.
g.,
batch
discharge),
or
timeframe
(
e.
g.,
after
6
months)
triggers
their
use.

°
Tiered
Testing
 
Any
of
a
series
of
tests
that
are
conducted
as
a
result
of
a
previous
test's
findings.

°
Total
Maximum
Daily
Load
(
TMDL)
 
The
amount
of
pollutant,
or
property
of
a
pollutant,
from
point,
nonpoint,
and
natural
background
sources,
that
may
be
discharged
to
a
water
quality­
limited
receiving
water.
Any
pollutant
loading
above
the
TMDL
results
in
violation
of
applicable
water
quality
standards.

°
Total
Organic
Carbon
(
TOC)
 
Measures
the
amount
of
organic
carbon
in
water.

NPDES
Permit
Writer
Training
Manual
­
G­
11
Glossary
of
Terms
°
Total
Suspended
Solids
(
TSS)
 
A
measure
of
the
filterable
solids
present
in
a
sample,
as
determined
by
the
method
specified
in
40
CFR
Part
136.

°
Toxic
Pollutant
 
Pollutants
or
combinations
of
pollutants,
including
disease­
causing
agents,
which
after
discharge
and
upon
exposure,
ingestion,
inhalation
or
assimilation
into
any
organism,
either
directly
from
the
environment
or
indirectly
by
ingestion
through
food
chains,
will,
on
the
basis
of
information
available
to
the
Administrator
of
EPA,
cause
death,
disease,
behavioral
abnormalities,
cancer,
genetic
mutations,
physiological
malfunctions,
(
including
malfunctions
in
reproduction)
or
physical
deformations,
in
such
organisms
or
their
offspring.
Toxic
pollutants
also
include
those
pollutants
listed
by
the
Administrator
under
CWA
Section
307(
a)(
1)
or
any
pollutant
listed
under
Section
405(
d)
which
relates
to
sludge
management.

°
Toxicity
Reduction
Evaluation
(
TRE)
 
A
site­
specific
study
conducted
in
a
stepwise
process
designed
to
identify
the
causative
agent(
s)
of
effluent
toxicity,
isolate
the
sources
of
toxicity,
evaluate
the
effectiveness
of
toxicity
control
options,
and
then
confirm
the
reduction
in
effluent
toxicity.

°
Toxicity
Test
 
A
procedure
to
determine
the
toxicity
of
a
chemical
or
an
effluent
using
living
organisms.
A
toxicity
test
measures
the
degree
of
effect
on
exposed
test
organisms
of
a
specific
chemical
or
effluent.

°
Treatability
Manual
 
Five­
set
library
of
EPA
guidance
manuals
that
contain
information
related
to
the
treatability
of
many
pollutants.
This
manual
can
be
used
in
developing
NPDES
permit
limitations
for
facilities
and/
or
pollutants
which,
at
the
time
of
permit
issuance,
are
not
subject
to
industry­
specific
effluent
guidelines.
The
five
volumes
that
comprise
this
series
include:
Vol.
I
­
Treatability
Data
(
EPA­
600/
8­
80­
042a);
Vol.
II
­
Industrial
Descriptions
(
EPA­
600/
8­
80­
042b);
Vol.
III
­
Technologies
(
EPA­
600/
8­
80­
042c);
Vol.
IV
­
Cost
Estimating
(
EPA­
600/
8­
80­
042d);
Vol.
V
­
Summary(
EPA­
600/
8­
80­
042e).

°
TSD
 
Abbreviation
for
the
Technical
Support
Document
Water
Qualitybased
Toxics
Control
(
EPA­
505/
2­
90­
001),
EPA
Office
of
Water
Enforcement
and
Permits,
1991.
It
contains
procedures
for
water
qualitybased
limitation
development.

°
TWTDS
 
Abbreviation
for
Treatment
Works
Treating
Domestic
Sewage.
Includes
all
POTWs
and
other
facilities
that
treat
domestic
wastewater,
and
facilities
that
do
not
treat
domestic
wastewater,
but
that
treat
or
dispose
of
sewage
sludge.

°
Upset
 
An
exceptional
incident
in
which
there
is
unintentional
and
temporary
noncompliance
with
the
permit
limit
because
of
factors
beyond
G­
12
­
NPDES
Permit
Writer
Training
Manual
Glossary
of
Terms
the
reasonable
control
of
the
permittee.
An
upset
does
not
include
noncompliance
to
the
extent
caused
by
operational
error,
improperly
designed
treatment
facilities,
inadequate
treatment
facilities,
lack
of
preventive
maintenance,
or
careless
or
improper
operation.

°
Variance
 
Any
mechanism
or
provision
under
Sections
301
or
316
of
the
CWA
or
under
40
CFR
Part
125,
or
in
the
applicable
"
effluent
limitations
guidelines"
which
allows
modification
to
or
waiver
of
the
generally
applicable
effluent
limitations
requirements
or
time
deadlines
of
the
CWA.
This
includes
provisions
which
allow
the
establishment
of
alternative
limitations
based
on
fundamentally
different
factors.

°
Wastesload
Allocation
(
WLA)
 
The
proportion
of
a
receiving
water's
total
maximum
daily
load
that
is
allocated
to
one
of
its
existing
or
future
point
sources
of
pollution.

°
Water
Quality­
Based
Effluent
Limit
(
WQBEL)
 
A
value
determined
by
selecting
the
most
stringent
of
the
effluent
limits
calculated
using
all
applicable
water
quality
criteria
(
e.
g.,
aquatic
life,
human
health,
and
wildlife)
for
a
specific
point
source
to
a
specific
receiving
water
for
a
given
pollutant.

°
Water
Quality
Criteria
 
Comprised
of
numeric
and
narrative
criteria.
Numeric
criteria
are
scientifically
derived
ambient
concentrations
developed
by
EPA
or
States
for
various
pollutants
of
concern
to
protect
human
health
and
aquatic
life.
Narrative
criteria
are
statements
that
describe
the
desired
water
quality
goal.

°
Water
Quality
Standard
(
WQS)
 
A
law
or
regulation
that
consists
of
the
beneficial
use
or
uses
of
a
waterbody,
the
numeric
and
narrative
water
quality
criteria
that
are
necessary
to
protect
the
use
or
uses
of
that
particular
waterbody,
and
an
antidegradation
statement.

°
Waters
of
the
United
States
 
All
waters
that
are
currently
used,
were
used
in
the
past,
or
may
be
susceptible
to
use
in
interstate
or
foreign
commerce,
including
all
waters
subject
to
the
ebb
and
flow
of
the
tide.
Waters
of
the
United
States
include
but
are
not
limited
to
all
interstate
waters
and
intrastate
lakes,
rivers,
streams
(
including
intermittent
streams),
mudflats,
sand
flats,
wetlands,
sloughs,
prairie
potholes,
wet
meadows,
play
lakes,
or
natural
ponds.
[
See
40
CFR
§
122.2
for
the
complete
definition.]

°
Whole
Effluent
Toxicity
(
WET)
 
The
total
toxic
effect
of
an
effluent
measured
directly
with
a
toxicity
test.

NPDES
Permit
Writer
Training
Manual
­
G­
13
