8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.0
POLLUTION
PREVENTION
PRACTICES
AND
WASTEWATER
TREATMENT
TECHNOLOGIES
In
general,
MP&
M
facilities
generate
process
wastewater
containing
metals,
cyanide,
oil
and
grease,
and
suspended
solids.
Pollution
prevention
practices
and
wastewater
treatment
technologies
currently
used
by
facilities
evaluated
for
the
final
rule
( 
MP&
M
facilities )
are
designed
to
remove
these
pollutants
before
they
are
discharged
to
either
a
receiving
stream
(
direct
discharge)
or
public
owned
treatment
works
(
indirect
discharge).
The
type
of
pollution
prevention
practice
and
wastewater
treatment
technology
a
MP&
M
facility
selects
depends
on
the
manufacturing
operations
generating
the
wastewater.
Many
facilities
have
implemented
process
modifications
for
waste
reduction.
Some
of
those
modifications
include
prolonging
process
bath
life
by
removing
contaminants,
redesigning
part
racks
to
reduce
dragout,
installing
spray
or
fog
nozzle
rinse
systems,
and
installing
dragout
recovery
tanks
(
1).

Most
MP&
M
facilities
rely
on
chemical
precipitation
and
gravity
or
membrane
clarification
to
remove
metals;
however,
certain
pretreatment
techniques
may
be
necessary
when
chelated
metals
or
hexavalent
chromium
are
present.
Facilities
that
generate
oily
wastewater
from
operations
such
as
machining
and
grinding
typically
use
chemical
emulsion
breaking
followed
by
gravity
or
membrane
clarification.
If
cyanide
is
present,
facilities
typically
use
oxidation
techniques
such
as
alkaline
chlorination.

This
section
describes
the
pollution
prevention
practices
and
wastewater
treatment
technologies
that
are
used
by
MP&
M
facilities,
in
the
first
instance,
to
prevent
the
generation
of
wastewater
pollutants
or,
secondarily,
to
reduce
the
discharge
of
wastewater
pollutants.
Section
8.1
describes
flow
reduction
practices,
Section
8.2
describes
in­
process
pollution
prevention
technologies,
Section
8.3
describes
management
practices
for
pollution
prevention,
Section
8.4
describes
technologies
used
for
the
preliminary
treatment
of
waste
streams,
and
Section
8.5
describes
end­
of­
pipe
wastewater
treatment
and
sludge
dewatering
technologies.
This
section
discusses
the
most
prevalent
treatment
technologies,
as
determined
by
survey
responses
and
site
visits,
in
place
at
facilities
evaluated
for
the
final
rule.
This
section
includes
descriptions
of
all
the
technologies
evaluated
for
the
final
rule
and
used
as
a
basis
for
the
MP&
M
effluent
guidelines
(
see
Section
9.0).
Additional
technologies
may
be
applicable
for
some
MP&
M
facilities,
depending
on
the
waste
streams
generated.
Additionally,
not
all
technologies
discussed
in
this
section
are
applicable
to
all
MP&
M
facilities;
the
applicability
of
a
technology
is
driven
by
the
unit
operations
performed
and
waste
streams
generated
on­
site.
EPA
presents
pollution
prevention
practices
and
wastewater
treatment
information
potentially
applicable
to
all
facilities
evaluated
for
the
final
rule
( 
MP&
M
facilities ).

8.1
Flow
Reduction
Practices
MP&
M
facilities
applies
flow
reduction
practices
to
process
baths
or
rinses
to
reduce
the
volume
of
wastewater
discharged.
Flow
reduction
practices
consist
of
optimizing
rinse
tank
design
and
configuration,
and
installing
flow
reduction
technologies
such
as
flow
restrictors
or
timers.
Table
8­
1
lists
various
flow
reduction
practices
and
the
number
8­
1
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
observations
at
EPA
MP&
M
site
visits
and
surveys
(
see
Section
3.0).
This
table
also
provides
EPA s
estimate
of
the
number
of
MP&
M
facilities
employing
the
various
flow
reduction
practices
based
on
occurrence
at
surveyed
facilities
and
their
respective
survey
weights.
The
following
subsections
discuss
these
flow
reduction
practices
in
greater
detail.

8.1.1
Rinse
Tank
Design
and
Innovative
Configurations
Rinsing
follows
many
proposed
MP&
M
operations1
to
remove
dirt,
oil,
or
chemicals
remaining
on
parts
or
racks
from
a
previous
unit
operation
(
i.
e.,
drag­
out).
Rinsing
improves
the
quality
of
the
surface
finishing
process
and
prevents
the
contamination
of
subsequent
process
baths.
Rinse
tank
design
and
rinsing
configuration
greatly
influence
water
usage.
The
key
objectives
of
optimal
rinse
tank
design
are
to
quickly
remove
drag­
out
solution
from
the
part
and
to
disperse
the
drag­
out
throughout
the
rinse
tank.
MP&
M
facilities
uses
various
rinsing
configurations.
The
most
common
are
countercurrent
cascade
rinsing,
drag­
out
rinsing,
and
spray
rinsing.
EPA
estimates
that
over
5,000
MP&
M
facilities
use
at
least
one
of
these
rinse
schemes
to
reduce
wastewater
flow.
The
use
of
single
overflow
rinse
tanks
following
each
process
tank
is
the
most
inefficient
use
of
rinse
water.
Multiple
rinse
tanks
connected
in
series
(
i.
e.,
cascade
rinsing)
reduce
the
water
needs
of
a
given
rinsing
operation
by
one
or
more
orders
of
magnitude
(
i.
e.,
less
water
is
needed
to
achieve
the
same
rinsing
quality).
Spray
rinsing,
where
the
part
is
suspended
over
a
tank
and
rinsed
with
water
applied
by
spray
nozzles,
also
may
be
used
to
reduce
water
use
requirements,
although
less
than
countercurrent
cascade
rinses.
Below
are
descriptions
of
some
of
the
common
rinse
types.

Cascade
Rinsing
Cascade
rinsing
is
a
method
of
reusing
water
from
one
rinsing
operation
to
another,
less
critical
rinsing
operation
before
being
discharged
to
treatment.
Some
rinse
waters
acquire
chemical
properties,
such
as
low
pH,
that
make
them
desirable
for
reuse
in
other
rinse
systems.
For
example,
water
from
an
acid
treatment
rinse
may
be
reused
in
an
alkaline
treatment
rinse.
In
this
case,
the
rinse
water
both
removes
drag­
out
from
the
work
piece
and
neutralizes
the
drag­
out.

1Note:
EPA
evaluated
a
number
of
unit
operations
for
the
May
1995
proposal,
January
2001
proposal,
and
June
2002
NODA
(
see
Tables
4­
3
and
4­
4).
However,
EPA
selected
a
subset
of
these
unit
operations
for
regulation
in
the
final
rule
(
see
Section
1.0).
For
this
Section,
the
term
 
proposed
MP&
M
operations 
means
those
operations
evaluated
for
the
two
proposals,
NODA,
and
final
rule.
The
term
 
final
MP&
M
operations 
means
those
operations
defined
as
 
oily
operations 
(
see
Section
1.0,
40
CFR
438.2(
f),
and
Appendix
B
to
Part
438)
and
regulated
by
the
final
rule.

8­
2
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8­
3
Table
8­
1
MP&
M
Flow
Reduction
Technologies
Technology
Technology
Description
Demonstration
Status
Number
of
Facilities
Visited
Using
the
Technologya
Number
of
Survey
Facilities
Using
the
Technologyb
Estimated
Number
of
MP&
M
Facilities
Using
the
Technologyc
Countercurrent
Cascade
Rinsing
Series
of
consecutive
rinse
tanks
that
are
plumbed
to
cause
water
to
flow
from
one
tank
to
another
in
the
direction
opposite
of
the
work
flow.
Water
is
introduced
into
the
last
tank
of
the
series,
making
it
the
cleanest,
and
is
discharged
from
the
first
tank,
which
has
the
highest
concentration
of
pollutants.
110
130
1,569
Drag­
Out
Rinsing
Stagnant
rinse,
initially
of
fresh
water,
positioned
immediately
after
process
tanks.
The
drag­
out
rinse
collects
most
of
the
drag­
out
from
the
process
tank,
preventing
it
from
entering
the
subsequent
flowing
rinses.
Drag­
out
rinse
is
commonly
reused
as
make­
up
for
heated
process
bath
to
replace
evaporative
loss.
62
139
1,737
Spray
Rinsing
Water
sprayed
on
parts
above
a
process
tank
or
drip/
drag­
out
tank;

uses
considerably
less
water
than
immersion
for
certain
part
configurations.
This
technology
can
also
be
performed
as
countercurrent
cascade
rinsing
with
spray
rinses
instead
of
overflow
immersion
rinses.
75
187
1,767
Flow
Restrictors
Equipment
that
prevents
the
flow
in
a
pipe
from
exceeding
a
predetermined
flow
rate.
Flow
restrictors
can
be
used
to
limit
the
flow
into
a
rinse
system.
For
continuously
flowing
rinses,
a
flow
restrictor
controls
the
flow
into
the
system,
ensuring
a
consistent,

optimum
flow
rate.
50
127
1,581
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Table
8­
1
(
Continued)

Technology
Technology
Description
Demonstration
Status
Number
of
Facilities
Visited
Using
the
Technologya
Number
of
Survey
Facilities
Using
the
Technologyb
Estimated
Number
of
MP&
M
Facilities
Using
the
Technologyc
Conductivity
Probes
Equipment
that
measures
the
conductivity
of
water
in
a
rinse
tank
to
regulate
the
flow
of
fresh
rinse
water
into
the
rinse
system.
A
solenoid
valve
on
the
rinse
system
fresh
water
supply
is
connected
to
the
controller,
which
opens
the
valve
when
a
preset
conductivity
level
is
exceeded
and
closes
the
valve
when
conductivity
is
below
that
level.
40
29
320
8­
4
Source:
MP&
M
site
visits,
MP&
M
sampling
episodes,
MP&
M
surveys
and
technical
literature.
Statistics
specific
to
wastewater­
discharging
facilities.

a
Indicates
the
number
of
MP&
M
facilities
visited
by
EPA
that
use
the
listed
technology.
EPA
visited
a
total
of
221
facilities.

b
Number
of
survey
facilities
based
on
data
collected
in
1996
detailed
survey
only.
The
1989
survey
did
not
request
this
information.
EPA
sent
the
1996
detailed
survey
to
311
facilities.

c
Indicates
the
estimated
number
of
MP&
M
facilities
currently
performing
this
technology
based
on
the
1996
detailed
survey.
EPA s
national
estimate
of
the
1996
detailed
survey
includes
approximately
4,900
facilities.
EPA
estimated
numbers
in
this
column
using
statistical
weighting
factors
for
the
1996
detailed
survey
respondents.
See
Section
3.0
for
a
discussion
of
the
development
of
national
estimates
and
statistical
survey
weights.
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Countercurrent
Cascade
Rinsing
Countercurrent
cascade
rinsing
refers
to
a
series
of
consecutive
rinse
tanks
that
are
plumbed
to
cause
water
to
flow
from
one
tank
to
another
in
the
direction
opposite
of
the
work
flow.
Fresh
water
flows
into
the
rinse
tank
located
farthest
from
the
process
tank
and
overflows
(
i.
e.,
cascades)
into
the
rinse
tank
that
is
closest
to
the
process
tank.
This
is
called
countercurrent
rinsing
because
the
work
piece
and
the
rinse
water
move
in
opposite
directions.
Over
time,
the
first
rinse
becomes
contaminated
with
drag­
out
solutions
and
reaches
a
stable
concentration
of
process
bath
constituents
that
is
lower
than
the
concentration
in
the
process
bath.
The
second
rinse
stabilizes
at
a
lower
concentration,
which
enables
less
rinse
water
to
be
used
than
if
only
one
rinse
tank
were
in
place.
The
more
countercurrent
cascade
rinse
tanks
(
three­
stage,
four­
stage,
etc.),
the
less
rinse
water
is
needed
to
adequately
remove
the
process
solution.
This
differs
from
a
single,
overflow
rinse
tank
where
the
rinse
water
is
composed
of
fresh
water
that
is
discharged
after
use
without
any
recycle
or
reuse.
Figure
8­
1
illustrates
countercurrent
cascade
rinsing.

Figure
8­
1.
Countercurrent
Cascade
Rinsing
The
rinse
rate
needed
to
adequately
dilute
drag­
out
depends
on
the
concentration
of
process
chemicals
in
the
initial
process
bath,
the
concentration
of
chemicals
that
can
be
tolerated
in
the
final
rinse
tank
to
meet
product
specifications,
the
amount
of
drag­
out
solution
carried
into
each
rinse
stage,
and
the
number
of
countercurrent
cascade
rinse
tanks.
These
factors
are
expressed
in
Equation
8­
1
(
2):

(
8­
1)

8­
5
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
where:

gal/
min.
Vr
=
the
flow
rate
through
each
rinse
stage,
gal/
min;
Co
=
the
concentration
of
the
contaminant(
s)
in
the
initial
process
bath,
mg/
L;
Cf
=
the
tolerable
concentration
of
the
contaminant(
s)
in
the
final
rinse
to
give
acceptable
product
cleanliness,
mg/
L;
n
=
the
number
of
rinse
stages
used;
and
VD
=
the
drag­
out
carried
into
each
rinse
stage,
expressed
as
a
flow
rate,

This
mathematical
rinsing
model
is
based
on
complete
rinsing
(
i.
e.,
removal
of
all
contaminants
from
the
work
piece)
and
complete
mixing
(
i.
e.,
homogeneous
rinse
water
in
each
rinse
stage).
Under
these
conditions,
each
additional
rinse
stage
can
reduce
rinse
water
use
by
90
percent.
However,
each
rinse
stage
needs
to
have
sufficient
residence
time
and
agitation
for
complete
mixing
to
occur
in
each
rinse
tank
to
achieve
these
conditions.
For
less
efficient
rinse
systems,
each
added
rinse
stage
reduces
rinse
water
use
by
50
to
75
percent.

Countercurrent
cascade
rinsing
systems
have
higher
capital
costs
than
do
overflow
rinses
and
require
more
space
to
accommodate
the
additional
rinse
tanks.
Also,
when
countercurrent
cascade
rinsing
is
used,
the
low
flow
rate
through
the
rinse
tanks
may
not
provide
the
needed
agitation
for
drag­
out
removal.
In
such
cases,
air
or
mechanical
agitation
may
be
added
to
increase
rinsing
efficiency.

Drag­
out
Rinsing
Drag­
out
rinse
is
a
stagnant
rinse,
initially
filled
with
fresh
water,
positioned
immediately
after
the
process
tank.
Work
pieces
are
rinsed
in
drag­
out
tanks
directly
after
exiting
the
process
bath.
The
drag­
out
rinse
collects
most
of
the
drag­
out
from
the
process
tank,
thus
preventing
it
from
entering
the
subsequent
flowing
rinses
and
reducing
pollutant
loadings
in
those
rinses.
Gradually,
the
concentration
of
process
chemicals
in
the
drag­
out
tank
rises.
In
the
most
efficient
configuration,
a
drag­
out
tank
follows
a
heated
process
tank
that
has
a
moderate
to
high
evaporation
rate.
A
portion
of
the
fluid
in
the
drag­
out
tank
returns
to
the
process
tank
to
replace
the
evaporative
loss.
The
level
of
fluid
in
the
drag­
out
tank
is
maintained
by
adding
fresh
water.
Electrolytic
recovery,
discussed
in
Section
8.2.6,
is
commonly
used
to
remove
dissolved
metals
from
drag­
out
tanks.

Spray
Rinsing
For
certain
work
piece
configurations,
spray
rinsing
uses
considerably
less
water
than
does
immersion
rinsing.
During
spray
rinsing,
the
parts
are
held
over
a
catch
tank
and
are
sprayed
with
water.
Water
then
drips
from
the
part
into
the
catch
tank,
and
is
then
either
recycled
to
the
next
stage
or
discharged
to
treatment.
Spray
rinsing
can
occur
in
a
countercurrent
cascade
configuration,
further
reducing
water
use.
Spray
rinsing
can
enhance
draining
over
a
process
8­
6
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
bath
by
diluting
and
lowering
the
viscosity
of
the
process
fluid
film
clinging
to
the
work
piece.
Using
spray
rinsing
can
control
rinse
water
flow.

8.1.2
Additional
Design
Elements
In
addition
to
rinse
configuration,
unit
operations
can
be
modified
in
other
ways
to
reduce
drag­
out
of
process
bath
chemicals.
For
example,
air
knives
and
drip
tanks
reduce
the
pollutant
loading
and
volume
of
rinse
water
requiring
treatment.
Other
aspects
of
good
rinse
tank
design
include
positioning
the
water
inlet
and
discharge
points
of
the
tank
at
opposite
locations
in
the
tank
to
avoid
short­
circuiting,
using
air
agitation
for
better
mixing,
using
a
flow
distributor,
and
using
the
minimum
tank
size
possible
(
3).
Four
rinse
design
elements
are
described
in
more
detail
below.

Air
Knives
Air
knives
are
high­
pressure
air
blowers
installed
over
a
process
tank
or
drip
shield
and
are
designed
to
remove
drag­
out
by
blowing
the
liquid
off
the
surface
of
work
pieces
and
racks
and
into
a
catch
tank.
Liquid
from
the
catch
tank
is
pumped
back
to
the
process
tank.
Air
knives
are
most
effective
with
flat
parts
and
cannot
be
used
to
dry
surfaces
that
passivate
or
stain
due
to
oxidation.

Drip
Shields
Drip
shields
are
inclined
sheets
installed
between
process
tanks
and
rinse
tanks
to
recover,
and
drain
to
the
process
tank,
process
fluid
that
drips
from
racks
and
barrels
and
would
otherwise
fall
into
rinse
tanks
or
onto
the
floor.
Often,
drip
shields
are
composed
of
polypropylene
or
another
inert
material.

Drip
Tanks
Drip
tanks
are
installed
immediately
after
the
process
tank.
Work
pieces
exiting
a
process
bath
are
held
over
the
drip
tank
and
the
process
fluid
that
drips
from
the
work
pieces
collects
in
the
drip
tank.
When
enough
fluid
is
collected
in
the
drip
tank,
the
fluid
flows
back
to
the
process
tank.

Long
Dwell
Time
Automatic
finishing
lines
can
be
programmed
to
include
optimum
drip
times.
Long
dwell
times
over
the
process
tank
reduce
the
volume
of
drag­
out
reaching
the
rinsing
system.
On
manual
lines,
racks
can
be
hung
on
bars
over
process
baths
to
allow
the
fluid
drip.
Barrels
can
be
rotated
over
the
process
bath
to
enhance
drainage.
Increases
in
drip
time
may
be
unsuitable
for
surfaces
that
can
be
oxidized
or
stained
by
exposure
to
air.

8­
7
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.1.3
Rinse
Water
Use
Control
Facilities
can
reduce
water
use
by
coordinating
and
closely
monitoring
rinse
water
requirements
(
e.
g.,
rinse
water
use
is
optimized
based
on
drag­
out
rates
so
that
the
rinse
quality
is
consistent).
Matching
water
use
to
rinse
water
requirements
optimizes
the
quantity
of
rinse
water
used
for
a
given
work
load
and
tank
arrangement
(
3).
Inadequate
controlling
water
use
negates
the
benefits
of
using
multiple
rinse
tanks
or
other
water
conservation
practices
and
results
in
a
high
water
usage.

Many
facilities
use
some
form
of
rinse
water
control.
The
four
most
common
methods
are
flow
restrictors
(
these
can
be
used
with
other
methods
to
regulate
the
rate
at
which
water
is
dispensed),
manual
control
(
i.
e.,
turning
water
valves
on
and
off
as
needed),
conductivity
controls,
and
timer
rinse
controls.
Using
data
from
the
1996
MP&
M
industry
survey,
EPA
estimates
there
are
over
1,900
MP&
M
facilities
using
this
equipment
to
control
rinse
water
flow.
These
are
discussed
below.

Flow
Restrictors
A
flow
restrictor
prevents
the
flow
in
a
pipe
from
exceeding
a
predetermined
flow
rate.
Flow
restrictors
are
commonly
installed
on
a
rinse
tank s
water
inlet.
These
devices
contain
an
elastomer
washer
that
flexes
under
pressure
to
maintain
a
constant
water
flow
regardless
of
pressure.
Flow
restrictors
can
maintain
a
wide
range
of
flow
rates,
from
less
than
0.1
gal/
min
to
more
than
10
gal/
min.
As
a
stand­
alone
device,
a
flow
restrictor
provides
a
constant
water
flow
and
is
therefore
best
suited
for
continuous
rinsing.
For
intermittent
rinsing
operations,
a
flow
restrictor
does
not
coordinate
the
rinse
flow
with
drag­
out
introduction.
Precise
control
with
intermittent
operations
typically
requires
a
combination
of
flow
restrictors
and
rinse
timers.
However,
for
continuous
rinsing
(
e.
g.,
continuous
electroplating
machines),
flow
restrictors
may
be
adequate
for
good
water
use
control.

Conductivity
Controllers
Conductivity
controllers
use
conductivity
probes
to
measure
the
conductivity
(
total
dissolved
solids
(
TDS))
of
water
in
a
rinse
tank
to
regulate
the
flow
of
fresh
rinse
water
into
the
rinse
system.
Conductivity
controllers
consist
of
a
controller,
a
meter
with
adjustable
set
points,
a
probe
that
is
placed
in
the
rinse
tank,
and
a
solenoid
valve.
As
parts
are
rinsed,
dissolved
solids
enter
the
water
in
the
rinse
tank,
raising
the
conductivity
of
the
water.
When
conductivity
reaches
a
set
point
where
the
water
can
no
longer
provide
effective
rinsing,
the
solenoid
valve
opens
to
allow
fresh
water
to
enter
the
tank.
When
the
conductivity
falls
below
the
set
point,
the
valve
closes
to
discontinue
the
fresh
water
flow.

In
theory,
conductivity
control
of
rinse
flow
is
a
precise
method
of
maintaining
optimum
rinsing
conditions
in
intermittent
rinsing
operations.
In
practice,
conductivity
controllers
work
best
with
deionized
rinse
water.
Incoming
fresh
water
conductivity
may
vary
day
to
day
and
season
to
season,
which
forces
frequent
set
point
adjustments.
In
addition,

8­
8
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
suspended
solids
and
nonionic
contaminants
(
e.
g.,
oil)
can
cause
inadequate
rinsing
and
are
not
measured
by
the
conductivity
probe.

Rinse
Timers
Rinse
timers
are
electronic
devices
that
control
a
solenoid
valve.
The
timer
usually
consists
of
a
button
that,
when
pressed,
opens
the
valve
for
a
predetermined
time
period,
usually
from
1
to
99
minutes.
After
the
time
period
has
expired,
the
valve
automatically
closes.
The
timer
may
be
activated
either
manually
by
the
operator
or
automatically
by
the
action
of
racks
or
hoists.
Automatic
rinse
timers
are
generally
preferred
for
intermittent
rinses
because
they
eliminate
operator
error.
Rinse
timers
installed
in
conjunction
with
flow
restrictors
can
provide
precise
control
when
the
incoming
water
pressure
may
rise
and
fall.
Rinse
timers
are
less
effective
in
continuous
or
nearly
continuous
rinse
operations
(
e.
g.,
continuous
electroplating
machines)
because
the
rinse
operates
nearly
continuously.

8.1.4
Pollution
Prevention
for
Process
Baths
Facilities
also
can
implement
measures
that
will
reduce
or
prevent
pollution
in
process
baths
to
reduce
the
drag­
out
pollutant
loadings
and
therefore
the
amount
of
drag­
out
solution
produced.
Examples
of
these
technologies
are
increasing
bath
temperature,
operating
at
lower
batch
concentration,
and
using
wetting
agents,
discussed
below:


Temperature
and
viscosity
are
inversely
related;
therefore,
operating
a
bath
at
the
highest
possible
temperature
will
lower
process
bath
viscosity
and
reduce
drag­
out.


Operating
at
the
lowest
possible
concentration
reduces
the
mass
of
chemicals
in
a
given
volume
of
drag­
out.
Also,
viscosity
and
concentration
are
directly
related;
therefore,
lower
process
bath
concentration
will
result
in
lower
process
bath
viscosity
and
less
drag­
out
volume.
Contaminants
and
other
process
bath
impurities
should
be
minimized,
if
possible,
to
extend
the
usefulness
of
the
bath,
reducing
the
frequency
of
treatment
or
disposal.


Adding
wetting
agents
or
surfactants
to
some
process
baths
reduces
viscosity
and
surface
tension,
thereby
significantly
reducing
drag­
out.

8.2
In­
Process
Pollution
Prevention
Technologies
This
section
describes
in­
process
pollution
prevention
technologies
used
at
MP&
M
facilities
to
reduce
pollutant
loadings
to
the
wastewater
treatment
system.
Table
8­
2
lists
a
number
of
in­
process
pollutant
prevention
technologies.
This
table
also
provides
EPA s
estimate
of
the
number
of
MP&
M
facilities
employing
the
various
in­
process
pollutant
8­
9
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8­
10
Table
8­
2
MP&
M
In­
Process
Pollution
Prevention
Technologies
Technology
Technology
Description
Demonstration
Status
Number
of
Facilities
Visited
Using
the
Technologya
Number
of
Survey
Facilities
Using
the
Technologyb
Estimated
Number
of
MP&
M
Facilities
Using
the
Technologyc
Evaporation
with
Condensate
Recovery
Removes
water
by
evaporation,
leaving
a
concentrated
residue
for
disposal
and
water
vapor
for
condensation
and
reuse.
7
15
147
Ion
Exchange
(
in­

process)
Removes
metal
salts
from
electroplating
rinse
water
using
combined
cation
and
anion
exchange.
Effluent
(
permeate)
from
the
ion
exchange
flows
back
to
the
electroplating
rinse
system.
Ion
exchange
regenerants
are
either
discharged
to
the
end­
of­
pipe
chemical
precipitation
unit
for
metals
removal
or
to
electrolytic
recovery
for
metals
recovery.
35
33
437
Reverse
Osmosis
Forces
wastewater
through
a
membrane
at
high
pressure,
leaving
a
concentrated
stream
of
pollutants
for
disposal.
Reverse
osmosis
may
provide
an
effluent
clean
enough
for
reuse.
3
1
3
Centrifugation
of
Painting
Water
Curtains
Removes
the
heavier
solids
from
the
water
curtain
by
centrifugation,

allowing
the
water
to
be
reused.
The
solids
are
collected
as
a
cake
in
the
basket
of
the
centrifuge.
This
technology
can
achieve
closed­
loop
reuse
of
water
curtains.
3
1
12
Filtration
of
Painting
Water
Curtains
Removes
solids
by
filtration
(
cloth,
sand,
diatomaceous
earth,
etc.)

followed
by
reuse.
This
technology
can
achieve
closed­
loop
reuse
of
water
curtains.
2
3
20
Settling
of
Painting
Water
Curtains
Removes
the
heavier
solids
from
the
water
curtains
by
gravity
separation.
This
technology
can
be
used
in
conjunction
with
other
removal
technologies
to
lessen
the
solids
loading.
5
5
23
Biocide
Addition
to
Lengthen
Coolant
Life
Can
impede
the
growth
of
microorganisms
that
cause
rancidity.

Machining
coolant
is
often
discarded
as
it
becomes
rancid.
9
27
216
Centrifugation
of
Machinery
Coolant
Removes
the
solids
from
the
coolant
by
centrifugation
to
extend
its
usable
life.
Some
high­
speed
centrifuges
can
also
perform
liquid­
liquid
separation
to
remove
tramp
oils
and
further
extend
coolant
life.
18
10
78
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Table
8­
2
(
Continued)

Technology
Technology
Description
Demonstration
Status
Number
of
Facilities
Visited
Using
the
Technologya
Number
of
Survey
Facilities
Using
the
Technologyb
Estimated
Number
of
MP&
M
Facilities
Using
the
Technologyc
Filtration
of
Machinery
Coolant
Removes
the
solids
from
the
coolant
using
filters
such
as
cloth,
sand,
or
carbon
to
extend
its
usable
life.
18
18
142
Skimming
of
Tramp
Oils
in
Machinery
Coolants
Removes
tramp
oils
using
mechanical
skimming
to
extend
coolant
life.
Tramp
oil
buildup
often
makes
machining
coolant
unusable.
8
9
82
Pasteurization
of
Machinery
Coolants
Kills
the
microorganisms
that
cause
rancidity
using
heat.
Machining
coolant
is
often
discarded
as
it
becomes
rancid.
2
2
18
General
Filtration
of
Baths
and
Solutions
Removes
metals
and
other
impurities
from
process
tanks,
including
electrolytic
plating
solutions
and
acid/
alkaline
cleaning
tanks.

Increases
bath
longevity.
Technologies
include
paper
filters,
carbon
adsorption,
and
magnetic
separators.
6
Electrolytic
Recovery
(
Electrowinning)
Recovers
dissolved
metals
from
concentrated
sources
using
an
electrochemical
process.
For
rinses,
electrolytic
recovery
is
typically
restricted
to
drag­
out
rinses.
Flowing
rinses
are
generally
too
dilute
for
efficient
electrolytic
recovery.
This
technology
effectively
recovers
metals
from
ion
exchange
regenerants.
22
23
142
8­
11
Source:
MP&
M
site
visits,
MP&
M
sampling
episodes,
MP&
M
surveys
and
technical
literature.
Statistics
specific
to
wastewater­
discharging
facilities.

a
Indicates
the
number
of
MP&
M
facilities
visited
by
EPA
that
use
the
listed
technology.
EPA
visited
a
total
of
221
facilities.

b
Number
of
survey
facilities
based
on
data
collected
in
1996
detailed
survey
only.
The
1989
survey
did
not
request
this
information.
EPA
sent
the
1996
detailed
survey
to
311
facilities.

c
Indicates
the
estimated
number
of
MP&
M
facilities
currently
performing
this
technology
based
on
the
1996
detailed
survey.
EPA s
national
estimate
of
the
1996
detailed
survey
includes
approximately
4,900
facilities.
EPA
estimated
numbers
in
this
column
using
statistical
weighting
factors
for
the
1996
detailed
survey
respondents.
See
Section
3.0
for
a
discussion
of
the
development
of
national
estimates
and
statistical
survey
weights.
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
prevention
technologies
based
on
occurrence
at
surveyed
facilities
and
their
respective
survey
weights.
In­
process
pollution
prevention
technologies
can
be
applied
to
process
baths
or
rinses.
Not
all
technologies
discussed
in
this
subsection
are
applicable
to
all
MP&
M
facilities.

Process
baths
become
contaminated
with
impurities
that
affect
their
performance.
The
sources
of
process
bath
contamination
include:
(
1)
breakdown
of
process
chemicals;
(
2)
buildup
of
by­
products
(
e.
g.,
carbonates);
(
3)
contamination
from
impurities
in
make­
up
water,
chemicals,
or
anodes;
(
4)
corrosion
of
parts,
racks,
tanks,
heating
coils,
etc.;
(
5)
drag­
in
of
chemicals;
(
6)
errors
in
bath
additions;
and
(
7)
airborne
particles
entering
the
tank.
If
not
properly
maintained,
process
baths
become
prematurely
unusable
and
require
disposal.
Regeneration
and
maintenance
techniques
help
keep
baths
in
good
operating
condition,
thereby
extending
the
useful
lives
of
process
solutions.
Using
these
technologies
reduces
the
frequency
of
process
bath
discharges,
and
therefore
reduces
pollutant
loadings
to
the
wastewater
treatment
system.
This,
in
turn,
reduces
wastewater
treatment
requirements
and
sludge
disposal
costs.

Rinsing
removes
residual
process
chemicals
from
the
surface
of
a
work
piece.
As
more
and
more
work
pieces
are
rinsed,
the
concentration
of
process
chemicals
(
contaminants)
in
the
rinse
water
increases.
At
some
point,
the
concentration
of
process
chemicals
in
the
rinse
water
becomes
so
high
that
an
unacceptable
amount
of
process
chemicals
remain
on
the
surface
of
the
work
piece.
When
this
occurs,
clean
water
is
added
to
the
rinse
solution
to
lower
the
concentration
of
process
chemicals
to
a
level
that
will
not
impact
the
quality
of
the
work
piece.
Overflow
from
the
rinsing
operation
goes
to
treatment
for
removal
of
the
residual
process
chemicals.
For
continuous
processing
operations,
clean
water
may
continuously
flow
into
the
rinse
process
to
ensure
that
the
concentration
of
contaminants
will
not
exceed
the
quality
limit
for
the
work
piece.

This
section
describes
the
following
technologies
used
to
treat
and
reuse
process
solutions:

 
Activated
carbon
adsorption;

 
Carbonate
freezing;

 
Centrifugation
and
pasteurization
of
machining
coolants;

 
Centrifugation
and
recycling
of
painting
water
curtains;

 
Electrodialysis;

 
Electrolytic
recovery;

 
Evaporation;

 
Filtration;

 
Ion
exchange;
and
 
Reverse
osmosis.

8.2.1
Activated
Carbon
Adsorption
Activated
carbon
adsorption
is
a
common
method
of
removing
organic
contaminants
from
electroplating
baths.
Process
solution
flows
through
a
filter
where
the
carbon
8­
12
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
adsorbs
organic
impurities
that
result
from
the
breakdown
of
bath
constituents.
Carbon
adsorption
can
be
either
a
continuous
or
batch
operation,
depending
on
the
site s
preference.
Carbon
treatment
is
most
commonly
applied
to
nickel,
copper,
zinc,
and
cadmium
electroplating
baths
but
also
can
be
used
to
remove
organic
contaminants
from
paint
curtains.

8.2.2
Carbonate
 
Freezing 

Carbonate
 
freezing 
removes
excessive
carbonate
buildup
by
forming
carbonate
salt
crystals
at
a
low
temperature
that
are
then
removed.
MP&
M
facilities
most
often
apply
this
process
to
electroplating
baths
formulated
with
sodium
cyanide.
Carbonates
build
up
in
the
process
bath
by
the
breakdown
of
cyanide
(
especially
at
high
temperatures)
and
the
adsorption
of
carbon
dioxide
from
the
air.
An
excessive
carbonate
concentration
reduces
the
product
quality
of
many
metal
finishing
operations.
Carbonate
 
freezing 
takes
advantage
of
the
low
solubility
of
carbonate
salts
in
the
sodium
cyanide
bath.
The
method
lowers
the
bath
temperature
to
approximately
26
°
F
(­
3
°
C),
at
which
point
hydrated
salt
(
Na2
CO3
 
10H2
O)
crystallizes
out
of
solution.
The
crystallized
carbonate
can
be
removed
by
decanting
the
fluid
into
another
tank
or
by
filtration.

8.2.3
Centrifugation
and
Pasteurization
of
Machining
Coolants
Most
machining
coolants
contain
water­
soluble
oil
in
water.
The
water­
soluble
coolant
typically
is
pumped
from
a
sump,
over
the
machining
tool
and
work
piece
during
machining,
and
back
to
the
sump.
Over
a
period
of
time,
recycled
coolant
becomes
ineffective,
or
spent,
for
one
or
more
of
the
following
reasons:

 
The
concentration
of
suspended
solids
in
the
coolant
begins
to
inhibit
performance;

 
Nonemulsified,
or
 
tramp, 
oil
collects
on
the
surface
of
the
coolant,
inhibiting
performance;

 
The
coolant
becomes
rancid
due
to
microbial
growth;
or
 
Coolant
additives
are
consumed
by
drag­
out
and
organic
breakdown,
thus
reducing
corrosion
prevention
and
lubrication
properties.

As
shown
in
Table
8­
2,
EPA
estimates
that
nearly
300
MP&
M
facilities
use
centrifugation
and
biocide/
pasteurization
processes
to
extend
the
life
of
their
water­
soluble
coolants.

Coolant
recycling
is
most
effective
when
facilities
minimize
the
number
of
different
coolants
used
on­
site
and
use
a
centralized
coolant
recycling
system.
However,
some
facilities
may
not
be
able
to
use
a
single
recycling
system
because
of
multiple
coolant
types
required
by
product
or
customer
specifications.
In
this
case,
facilities
may
need
to
purchase
dedicated
coolant
recycling
systems
for
each
type
of
coolant
used.

8­
13
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Using
a
centrifugal
separator
and
pasteurization
unit
can
extend
the
useful
life
of
machining
coolants.
The
separator
is
a
rotating
chamber
that
uses
centrifugal
force
to
push
the
coolant
through
a
mesh
chamber,
leaving
behind
solid
contaminants
of
sludge.
Sludge
is
scraped
from
the
centrifuge
and
collected
in
a
sludge
hopper.
Some
high­
speed
centrifuges
also
can
perform
liquid­
liquid
separation
to
remove
tramp
oils.
The
coolant
undergoes
pasteurization
after
separation
to
kill
the
microorganisms
that
cause
bacterial
growth.
Adding
a
biocide
can
also
control
bacterial
growth.
Figure
8­
2
shows
a
diagram
of
a
typical
machine
coolant
recycling
system.

Figure
8­
2.
Machine
Coolant
Recycling
System
Centrifugal
separators
are
very
reliable
and
require
only
routine
maintenance,
such
as
periodic
cleaning
and
removal
of
accumulated
solids.
Flow
rate
is
the
primary
operating
factor
to
control.
The
sludge
generated
from
this
technology
is
commonly
classified
as
a
hazardous
waste,
based
on
the
metal
type
processed
and
the
amount
of
metal
that
dissolves
into
the
coolant.
Facilities
typically
haul
the
sludge
off­
site
for
treatment
and
disposal.

Centrifugation
and
pasteurization
can
be
used
in
conjunction
with
oil
skimming
and
biocide
addition
to
reduce
coolant
discharge
and
pollutant
generation
at
the
source.
Oil
skimming
using
a
vertical
belt
system
(
described
in
Section
8.4.5.2)
removes
large
amounts
of
tramp
hydraulic
oils
floating
on
the
surface
of
the
machine
coolant.
Oil
skimming
and
biocide
addition
can
further
extend
the
life
of
water­
soluble
coolant,
thereby
reducing
the
amount
of
coolant
and
wastewater
requiring
treatment
and
disposal,
and
minimizing
fresh
coolant
requirements.

8.2.4
Centrifugation
and
Recycling
of
Painting
Water
Curtains
Water
curtains
are
a
continuous
flow
of
water
behind
the
work
piece
being
spray
painted
in
a
paint
booth.
The
water
traps
paint
overspray
and
is
continuously
recirculated
in
the
paint
curtain
until
the
solids
content
in
the
wastewater
necessitates
either
in­
process
treatment
and
recycling
or
discharge.
Based
on
data
from
the
1996
MP&
M
detailed
survey,
approximately
12
MP&
M
facilities
centrifuge
and
recycle
water
from
their
paint
curtains.

8­
14
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Wastewater
from
painting
water
curtains
commonly
contains
organic
pollutants
as
well
as
certain
metals.
Eliminating
the
discharge
of
wastewater
from
painting
water
curtains
may
eliminate
the
need
for
an
end­
of­
pipe
treatment
step
for
organic
pollutants
at
certain
facilities.
Moreover,
if
a
facility
uses
only
painting
water
curtains
and
continuously
recycles
the
water,
the
facility
would
not
need
end­
of­
pipe
wastewater
treatment.

Figure
8­
3
shows
a
diagram
of
a
typical
in­
process
centrifugation
and
recycling
treatment
system
for
a
paint
curtain.
Centrifugal
separators
remove
the
solids
and
recycle
the
water
curtain,
eliminating
the
need
for
discharge.
This
system
can
recycle,
the
paint
curtain
water
continuously.
The
system
pumps
the
water
curtain
from
the
paint
curtain
sump
to
a
holding
tank,
then
through
the
centrifugal
separator,
which
separates
the
solids
from
the
wastewater
(
see
section
8.2.3).
Solids
from
the
centrifuge
are
hauled
for
off­
site
disposal,
while
the
treated
wastewater
is
returned
to
the
paint
booth.
Centrifugation
of
the
paint
curtain
proceeds
until
all
wastewater
is
treated
and
only
sludge
remains
in
the
paint
curtain
sump.
Operators
must
remove
the
sludge
in
the
paint
curtain
sump
either
manually,
with
a
sludge
pump,
or
by
vacuum
truck.
The
facility
may
add
detactifiers
before
centrifugation
to
increase
the
solid
separation
efficiency.
Detactifiers
make
the
paint
solids
less
sticky,
allowing
them
to
be
more
easily
removed
from
the
centrifuge.
Make­
up
water
is
added
to
the
system
to
compensate
for
evaporation.

Figure
8­
3.
Centrifugation
and
Recycling
of
Painting
Water
Curtains
As
discussed
in
Section
8.2.3,
centrifugal
separators
are
very
reliable
and
require
only
routine
maintenance.
Flow
rate
is
the
primary
operating
factor
to
control.
One
disadvantage
of
this
technology
is
that
it
may
not
be
economically
feasible
for
facilities
generating
only
a
small
amount
of
paint
curtain
wastewater.
Facilities
that
have
multiple
sumps
can
use
portable
centrifuges.

8­
15
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
The
sludge
generated
from
painting
water
curtains
is
commonly
classified
as
a
hazardous
waste,
based
on
the
type
of
paint
used,
and
typically
is
hauled
off­
site
for
treatment
and
disposal.
See
Appendix
D
for
more
information
on
pollution
prevention
practices
with
painting
operations.

8.2.5
Electrodialysis
Electrodialysis
is
a
process
in
which
dissolved
colloidal
species
are
exchanged
between
two
liquids
through
selective
semipermeable
membranes
(
11).
The
technology
applies
a
direct
current
across
a
series
of
alternating
anion
and
cation
exchange
membranes
to
remove
dissolved
metal
salts
and
other
ionic
constituents
from
solutions.

An
electrodialysis
unit
consists
of
a
rectifier
and
a
membrane
stack.
The
rectifier
converts
alternating
current
to
direct
current.
The
stack
consists
of
alternating
anion­
and
cation­
specific
membranes
that
form
compartments.
As
the
feed
stream
enters
the
unit,
ions
move
across
the
electrodialysis
membranes,
forming
a
concentrated
stream
and
a
deionized
stream.
When
the
compartments
are
filled,
a
direct
current
is
applied
across
each
membrane
in
the
stack.
Cations
traverse
one
cation­
specific
membrane
in
the
direction
of
the
cathode
and
are
trapped
in
that
concentrate
compartment
by
the
next
membrane,
which
is
anion­
specific.
Anions
from
the
neighboring
compartment
traverse
the
anion­
specific
membrane
in
the
direction
of
the
anode,
joining
the
cations,
and
are
likewise
trapped
in
the
concentrate
compartment
by
the
next
cation­
specific
membrane.
In
this
way,
the
technology
depletes
the
feed
stream
of
ions,
and
traps
anions
and
cations
in
each
concentrate
compartment.
Facilities
typically
use
electrodialysis
to
remove
metal
ions
from
electroplating
wastewater.
Figure
8­
4
shows
a
diagram
of
an
electrodialysis
cell.

8­
16
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Figure
8­
4.
Electrodialysis
Cell
By
using
the
electrodialysis
cell,
facilities
remove
impurities
from
the
process
bath,
extending
its
life.
Facilities
can
treat
the
removed
concentrate
stream
on­
site,
or
haul
it
off­
site
for
disposal,
treatment,
or
metals
reclamation.

8.2.6
Electrolytic
Recovery
Electrolytic
recovery
is
an
electrochemical
process
used
to
recover
metal
contaminants
from
many
types
of
process
solutions
and
rinses,
such
as
electroplating
rinse
waters
and
baths.
Electrolytic
recovery
removes
metal
ions
from
a
waste
stream
by
processing
the
stream
in
an
electrolytic
cell,
which
consists
of
a
closely
spaced
anode
and
cathode.
Equipment
consists
of
one
or
more
cells,
a
transfer
pump,
and
a
rectifier.
Current
is
applied
across
the
cell
and
metal
cations
are
deposited
on
the
cathodes.
The
waste
stream
is
usually
recirculated
through
the
cell
from
a
separate
tank,
such
as
a
drag­
out
recovery
rinse.

Facilities
typically
apply
electrolytic
recovery
to
solutions
containing
either
nickel,
copper,
precious
metals,
or
cadmium.
Chromium
cannot
be
electrolytically
recovered
because
it
exists
primarily
in
anionic
forms
such
as
dichromate.
Drag­
out
rinses
and
ion­
exchange
regenerant
are
solutions
that
commonly
are
processed
using
electrolytic
recovery.
Some
solutions
require
pH
adjustment
prior
to
electrolytic
recovery.
Acidic,
metal­
rich,
cation
regenerant
is
an
excellent
candidate
stream
for
electrolytic
recovery
and
is
often
electrolytically
8­
17
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
recovered
without
pH
adjustment.
In
some
cases,
when
the
target
metal
concentration
is
reached,
the
waste
stream
can
act
as
cation
regenerant.

The
capacity
of
electrolytic
recovery
equipment
depends
on
the
total
cathode
area
and
the
maximum
rated
output
of
the
rectifier.
Units
are
available
with
a
cathode
area
ranging
from
1
ft2
to
100
ft2
or
larger,
and
an
output
of
10
to
1,000
amperes
or
more.
Faraday s
law,
which
states
the
amount
of
chemical
change
produced
by
an
electric
current
is
proportional
to
the
quantity
of
electricity
used,
determines
theoretical
electrolytic
recovery
rates.
Theoretical
recovery
rates
range
from
1.09
grams/
amp­
hour
for
nickel
to
7.35
grams/
amp­
hour
for
monovalent
gold.
Actual
rates
are
usually
much
lower
and
depend
on
the
metal
concentration
in
the
waste
stream.
At
concentrations
under
100
mg/
L,
electrolytic
recovery
rates
may
be
below
10
percent
of
the
theoretical
maximum.

Electrolytic
recovery
units
use
various
types
of
cations,
depending
mainly
on
the
concentration
of
metal
in
the
waste
stream.
Cathodes
are
often
classified
by
their
surface
area.
Flat­
plate
cathodes
have
the
lowest
surface
area
and
are
used
only
for
recovering
metal
from
metal­
rich
waste
streams
(
usually
1,000
to
20,000
mg/
L
of
metal).
Reticulate
cathodes,
which
have
a
metallized
woven
fiber
design,
have
a
surface
area
10
times
greater
than
their
apparent
area.
These
cathodes
are
effective
over
a
wide
range
of
metal
concentrations
but
typically
are
used
where
the
dissolved
metal
concentration
is
below
100
mg/
L.
Carbon
and
graphite
cathodes
have
the
highest
surface
area
per
unit
of
apparent
area.
Their
use
is
usually
restricted
to
metal
concentrations
below
1,000
mg/
L.

Reticulate
or
carbon
cathodes
can
recover
metals
in
electrolytes
to
concentrations
as
low
as
5
mg/
L.
Electrolytes
are
substances
that
dissociate
into
ions
in
solution
(
i.
e.,
water),
thereby
becoming
electrically
conducting
(
4).
In
practice,
however,
the
target
effluent
concentration
for
most
applications
is
50
to
250
mg/
L
or
higher
because
of
the
time
and
energy
required
to
achieve
concentrations
less
than
100
mg/
L.
With
flat­
plate
cathodes,
the
target
effluent
concentration
is
usually
above
500
mg/
L,
because
plating
efficiency
drops
as
concentration
falls.
Plating
time
required
to
lower
the
concentration
of
a
pollutant
from
100
to
10
mg/
L
can
be
several
times
longer
than
that
required
to
lower
the
concentration
from
10,000
mg/
L
to
100
mg/
L.
Also,
unit
energy
costs
(
measured
in
dollars
per
pound
of
metal
recovered)
increase
substantially
at
lower
metal
concentrations.

Electrolytic
recovery
units
have
relatively
low
labor
requirements.
Units
recovering
dissolved
metal
from
drag­
out
rinse
tanks
only
may
require
occasional
cleaning
and
maintenance.
Units
treating
batch
discharges
from
ion­
exchange
units
(
see
Section
8.2.8.1)
require
more
labor
due
to
the
higher
metal
content
of
the
solution
and
the
resultant
increase
in
cathode
loading
frequency.
Energy
costs
for
this
technology
can
be
high,
and,
in
some
cases,
exceed
the
recovery
value
of
the
metal.
Energy
requirements
depend
on
several
factors,
including
required
voltage,
rectifier
efficiency,
and
current
efficiency.
In
addition,
from
an
energy
standpoint,
electrolytic
recovery
removes
metals
from
concentrated
solutions
more
efficiently
than
from
dilute
solutions.
Electrode
replacement
costs
may
be
significant
for
units
8­
18
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
using
disposable
cathodes,
especially
for
high
metal
recovery
rates.
However,
if
electrodes
are
constructed
properly,
cathodes
and
anodes
may
last
more
than
five
years
for
most
applications.

Numerous
vendors
offer
electrolytic
recovery
technology.
The
technology
is
applicable
to
a
wide
range
of
processes,
drag­
out
rinses,
and
ion­
exchange
regenerants
due
to
the
diversity
of
materials
and
configurations
available
for
anodes
and
cathodes.
Electrolytic
recovery
is
not
applicable
to
flowing
rinses
due
to
the
lower
metal
concentrations
and
the
extended
time
required
for
metal
recovery.
In
most
cases,
this
technology
cannot
cost­
effectively
remove
dissolved
metals
to
concentrations
required
for
discharge
to
POTWs
or
surface
waters.

8.2.7
Evaporation
Evaporation
is
a
volume
reduction
and
water
recovery
technology
applicable
when
raw
water
costs
are
high
or
discharge
to
either
a
receiving
stream
or
the
local
sewerage
district
is
not
permitted.
EPA
estimates
there
are
147
MP&
M
facilities
using
evaporation
to
reduce
the
volume
of
their
waste
and
to
recover
and
reuse
their
water.
Evaporators
have
the
potential
to
recover
95
percent
of
the
water
in
a
waste
stream
for
reuse
in
the
process.
MP&
M
facilities
use
two
basic
types
of
evaporators:
atmospheric
and
vacuum.
Atmospheric
evaporators
are
more
prevalent
and
are
relatively
inexpensive
to
purchase
and
easy
to
operate.
Vacuum
evaporators
are
mechanically
more
sophisticated
and
are
more
energy­
efficient.
Facilities
typically
use
vacuum
evaporators
when
evaporation
rates
greater
than
50
to
70
gallons
per
hour
are
required.
MP&
M
facilities
use
evaporators
to
recover
metals
from
ion
exchange
regenerates,
to
reduce
the
volume
of
oily
wastes
that
require
off­
site
transfer,
and
to
recover
and
reuse
rinse
water
from
plating
operations.

Equipment
required
for
evaporation
systems
include
(
12):

 
Basket
strainers
in
lift
stations
and
sumps
to
prevent
items
like
shop
rags
from
reaching
the
evaporator;

 
Equalization
tanks
to
handle
batch
dumps
of
process
water;

 
An
oil
skimmer
in
the
equalization
tank
to
remove
floatable
oil;

 
Evaporators
(
either
vacuum
or
atmospheric);

 
Residue
holding
tanks;

 
Air
pollution
control
equipment;

 
A
condenser
to
capture
water
vapor
for
return
to
the
manufacturing
process;
and
 
Natural
gas
or
propane
tanks
for
evaporator
fuel
storage.

8­
19
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Residue
from
evaporators
can
be
recycled
if
sufficiently
pure,
disposed
of
off­
site,
or
used
for
energy
recovery
if
the
material
has
a
sufficient
BTU
content.

8.2.8
Filtration
Filtration
removes
suspended
solids
from
surface
finishing
operations.
EPA
estimates
there
are
nearly
150
MP&
M
facilities
that
use
filters
on
their
machining
and
grinding
operations
to
remove
solids,
debris,
or
swarf
from
machining
coolants.
If
solids
are
not
removed
from
machining
coolants,
they
may
cause
a
rough
or
burred
surface
on
the
work
piece.
Filtered
coolants
return
to
the
manufacturing
process.
In­
process
filtration
extends
the
life
of
the
coolant
and
reduces
the
amount
of
oil
and
grease
sent
to
treatment.
Filtration
equipment
includes
cartridge
filters,
precoat
diatomaceous
earth
filters,
sand,
and
multimedia
filters.

Cartridge
filters
are
available
with
either
in­
tank
or
external
configurations.
The
in­
tank
units
are
used
mostly
for
small
tanks
and
the
external
units
for
larger
tanks.
Most
cartridges
are
disposable;
however,
washable
and
reusable
filters
are
available,
which
further
reduce
waste
generation.
Precoat,
sand,
and
multimedia
filters
are
used
mostly
for
large
tanks.
The
filter
media
used
depends
on
the
chemical
and
physical
characteristics
of
the
bath,
which
determine
the
filter
material
type,
density,
nominal
micron
retention,
wet
strength,
mullen
burst,
and
air
permeability.
Material
type
is
important
to
ensure
the
media
is
compatible
with
the
liquid
being
filtered.
Media
density
is
how
close
or
dense
the
media
fibers
are
laid,
laminated,
or
woven.
Nominal
micron
retention
indicates
the
smallest
particle
size
the
media
will
retain
to
develop
a
filter
cake.
Flux
rate
through
the
filter
is
determined
by
the
air
permeability
characteristics.
All
filtration
systems
are
sized
based
on
solids
loading
and
the
required
flow
rate.

Membrane
filtration
also
can
remove
oils
and
metals
from
process
baths
or
rinses,
and
remove
solids
from
paint
curtains
or
tramp
oils
from
machine
coolants
to
extend
usable
life.
They
are
also
commonly
used
to
recover
and
recycle
electrophoretic
painting
( 
e­
coat )
solutions.
Membrane
filtration
is
a
pressure­
driven
process
that
separates
solution
components
based
on
molecular
size
and
shape.
Solvent
and
small
solutes
can
pass
through
the
membrane
while
the
membrane
retains
and
collects
larger
compounds
as
a
concentrated
waste
stream.
The
cleaner
permeate
can
be
reused
in
the
process
while
the
concentrated
waste
stream
is
discharged
to
treatment.
Figure
8­
5
shows
a
typical
membrane
filtration
unit.

8­
20
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Figure
8­
5.
Membrane
Filtration
Unit
8.2.8.1
Ion
Exchange
(
in­
process)

Ion
exchange
is
a
commonly
used
technology
within
MP&
M
facilities.
In
addition
to
water
recycling
and
chemical
recovery
applications,
ion
exchange
is
used
to
soften
or
deionize
raw
water
for
process
solutions.
Figure
8­
6
shows
a
typical
ion­
exchange
system.

Ion
exchange
is
a
reversible
chemical
reaction
that
exchanges
ions
in
a
feed
stream
for
ions
of
like
charge
on
the
surface
of
an
ion­
exchange
resin.
Resins
are
broadly
divided
into
cationic
or
anionic
types.
Typical
cation
resins
exchange
H+
for
other
cations,
while
anion
resins
exchange
OH­
for
other
anions
(
10).

8­
21
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Figure
8­
6.
Ion
Exchange
A
feed
stream
passes
through
a
column,
which
holds
the
resin.
The
feed
stream
is
usually
either
dilute
rinse
water
(
in­
process
ion
exchange)
or
treated
wastewater
(
end­
of­
pipe
ion
exchange).
Often,
prior
to
ion­
exchange
treatment,
the
feed
stream
passes
through
a
cartridge
filter
and
a
carbon
filter
to
remove
suspended
solids
and
organic
pollutants
that
foul
the
resin
bed.
The
exchange
process
continues
until
the
capacity
of
the
resin
is
reached
(
i.
e.,
an
exchange
has
occurred
at
all
the
resin
sites).
A
regenerant
solution
then
passes
through
the
column.
For
cation
resins,
the
regenerant
is
an
acid,
and
the
H+
ions
replace
the
cations
captured
from
the
feed
stream.
For
anion
resins,
the
regenerant
is
a
base,
and
OH­
ions
replace
the
anions
captured
from
the
feed
stream.
The
metals
concentration
is
much
higher
in
the
regenerant
than
in
the
feed
stream;
therefore,
the
ion­
exchange
process
not
only
separates
the
metals
from
the
waste
stream
but
also
results
in
a
more
concentrated
waste
stream.

MP&
M
facilities
use
ion
exchange
for
water
recycling
and
metal
recovery.
For
water
recycling,
cation
and
anion
columns
are
placed
in
series.
The
feed
stream
is
deionized
and
the
product
water
is
reused
for
rinsing.
Often,
the
system
can
achieve
closed­
loop
rinsing.
The
regenerant
from
the
cation
column
contains
metal
ions,
which
are
recoverable
in
elemental
form
via
electrolytic
recovery
(
see
Section
8.2.6).
The
anion
regenerant
typically
flows
to
wastewater
treatment.
Facilities
use
this
type
of
ion
exchange
to
recycle
relatively
dilute
rinse
streams.
Generally,
the
TDS
concentration
of
such
streams
must
be
below
500
mg/
L
to
maintain
an
8­
22
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
efficient
regeneration
frequency.
Reducing
drag­
out
can
enhance
the
efficiency
of
the
recovery
process.
Effluent
TDS
concentrations
of
2
mg/
L
or
less
are
typical.

When
facilities
are
seeking
only
metal
recovery,
they
use
a
single
or
double
cation
column
unit
containing
selective
resin.
These
resins
attract
divalent
cations
while
allowing
monovalent
cations
to
pass,
a
process
usually
called
metal
scavenging.
This
technology
is
efficient
if
the
metal
ions
being
scavenged
are
the
primary
source
of
ions
in
the
stream.
Ion
exchange
provides
effective
metals
recovery
even
when
the
metal
content
of
the
stream
is
only
a
small
fraction
of
the
TDS
present
in
the
stream,
making
scavenging
suitable
over
a
wider
range
of
TDS
than
water
recycling.
Scavenging
also
provides
a
highly
concentrated
regenerant,
particularly
suitable
for
electrolytic
recovery
(
see
Section
8.2.6).
Water
recycling
using
this
ion
exchange
configuration
is
not
possible
because
only
some
of
the
cations
and
none
of
the
anions
are
removed.
Standard
units
typically
achieve
effluent
metal
concentrations
of
under
0.5
mg/
L.

Many
process
wastewaters
are
excellent
candidates
for
ion
exchange,
including
the
rinse
water
from
plating
processes
of
chromium,
copper,
cadmium,
gold,
lead,
nickel,
tin,
tin­
lead,
and
zinc.
Ion
exchange
resins
usually
are
regenerated
using
inexpensive
chemicals
such
as
sulfuric
acid
and
sodium
hydroxide.
Gold­
bearing
resins
are
difficult
to
regenerate
and
frequently
require
incineration
to
recover
the
gold
content.
Lead
also
is
difficult
to
recover
from
ion
exchange
resins.
Methane
sulfonic
acid
and
fluoboric
acid
(
usually
not
suitable
for
electrolytic
recovery)
are
effective
regenerants
for
lead
ion
exchange
but
are
very
expensive.
Cyanide
rinse
waters
are
amenable
to
ion
exchange;
cation
resins
can
break
the
metal­
cyanide
complex
and
the
cyanide
is
removed
in
the
anion
column.
The
metals
in
the
cation
regenerant
can
be
recovered
electrolytically
and
the
cyanide
present
in
the
anion
regenerant
can
be
returned
to
the
process
or
discharged
to
treatment.

Ion­
exchange
equipment
ranges
from
small,
manual,
single­
column
units
to
multi­
column,
highly
automated
units.
Two
sets
of
columns
are
necessary
for
continuous
treatment;
one
set
receives
the
wastewater
flow
while
the
other
set
is
being
regenerated.
Thus,
two­
column
metal
scavenging
and
four­
column
deionizing
systems
are
common.
Automatic
systems
direct
the
wastewater
flow
and
initiate
regeneration
with
little
or
no
operator
involvement.

The
labor
requirements
for
ion
exchange
depend
on
the
automation
level
of
the
equipment.
Manual
systems
can
have
significant
labor
costs
associated
with
preparing,
transporting,
and
disposing
of
regenerants.
Automatic
systems
require
far
less
labor.
Resins
need
to
be
replaced
periodically
due
to
organic
contamination,
resin
oxidation,
and
fouling
from
suspended
solids.
This
process
can
be
hastened
by
misuse,
accidents,
or
poor
engineering.

Equipment
size
is
based
on
flow
rate
and
concentration.
Resin
capacity
varies
but
often
ranges
from
1
to
2
lbs/
ft3
.
Flow
rates
may
range
from
1
to
20
or
more
gpm.
Columns
typically
are
sized
to
handle
wastewater
flow
for
at
least
a
period
of
time
equal
to
that
required
for
regeneration.
Automatic
systems
are
sized
to
provide
continuous
treatment.
Regeneration
volume
typically
ranges
from
2
to
4
resin
bed
volumes
of
dilute
acid
or
caustic.
Concentrations
of
feed
stream
contaminants
generally
range
from
10
to
20
g/
L.

8­
23
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.2.8.2
Reverse
Osmosis
Reverse
osmosis
is
a
membrane
separation
technology
used
by
MP&
M
facilities
for
chemical
recovery
and
water
recycling.
The
system
pumps
dilute
rinse
water
to
the
surface
of
the
reverse
osmosis
membrane
at
pressures
of
400
to
1,000
pounds
per
square
inch
gauge
(
psig).
The
membrane
separates
the
feed
stream
into
a
reject
stream
and
a
permeate.
The
reject
stream,
containing
most
of
the
dissolved
solids
in
the
feed
stream,
is
retained
by
the
membrane
while
the
permeate
passes
through.
Reverse
osmosis
membranes
reject
more
than
99
percent
of
multivalent
ions
and
90
to
96
percent
of
monovalent
ions,
in
addition
to
organic
pollutants
and
nonionic
dissolved
solids.
The
permeate
stream
usually
is
of
sufficient
quality
to
be
recycled
as
rinse
water,
despite
the
small
percentage
of
monovalent
ions
(
commonly
potassium,
sodium
and
chloride)
that
pass
through
the
membrane.
Reverse
osmosis
equipment
is
similar
to
the
equipment
shown
in
Figure
8­
5.

A
sufficiently
concentrated
reject
stream
can
be
returned
directly
to
the
process
bath.
Recycling
the
stream
through
the
unit
more
than
once
or
by
increasing
the
feed
pressure
can
increase
the
reject
stream
concentration.
In
multiple­
stage
units
containing
more
than
one
membrane
chamber,
the
reject
stream
from
the
first
chamber
is
routed
to
the
second,
and
so
on.
The
combined
reject
streams
from
multistage
units
may,
in
some
cases,
have
high
enough
concentrations
to
go
directly
back
to
the
bath.

The
capacity
of
reverse
osmosis
equipment
generally
is
measured
in
flow
volume,
and
is
determined
by
the
membrane
surface
area
and
operating
pressure.
Increasing
the
surface
area
of
the
membrane
usually
increases
the
membrane
capacity.
Operating
at
higher
pressures
increases
the
permeate
flow
volume
per
unit
membrane
area
(
also
called
the
flux).
Reject
stream
concentration
increases
with
pressure
and
decreases
as
flow
volume
increases.

Facilities
may
need
to
prefilter
and
pretreat
the
feed
stream
to
lengthen
membrane
life
or
reduce
the
frequency
of
fouling;
filtration
to
remove
suspended
solids
is
usually
necessary.
Adjusting
pH
may
prevent
precipitation
as
the
feed
stream
is
concentrated,
but
it
may
make
the
concentrate
unfit
to
return
to
the
process
bath.

Reverse
osmosis
is
most
applicable
to
electroplating
rinse
waters,
including
electroplating
of
Watts
nickel,
bright
nickel,
brass
cyanide,
copper
cyanide,
and
zinc
cyanide.
This
technology
can
treat
TDS
concentrations
of
up
to
1,000
mg/
L.
Permeate
TDS
concentrations
of
250
mg/
L
or
less
are
typical,
and
the
dissolved
solids
are
mostly
commonly
monovalent
ions,
allowing
the
permeate
stream
to
be
reused
in
many
rinsing
operations.

The
maximum
achievable
reject
stream
concentration
for
basic
reverse
osmosis
equipment
is
approximately
20,000
mg/
L
TDS.
Multipass
and
multistage
units
achieve
concentrations
of
30,000
mg/
L
TDS
or
higher.
If
the
reject
stream
is
acceptable
to
return
directly
to
the
process
bath
and
the
permeate
is
recycled
as
rinse
water,
a
closed
loop
is
created.
However,
returning
the
reject
stream
directly
to
the
bath
is
uncommon
because
the
concentration
is
often
too
low.
When
the
reject
stream
concentration
is
not
high
enough
to
return
it
to
the
bath,

8­
24
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
it
can
be
concentrated
with
an
evaporator,
electrolytically
recovered,
or
discharged
to
wastewater
treatment.
When
evaporators
are
used,
however,
reverse
osmosis
loses
its
low­
energy
advantage
over
other
in­
process
reuse
and
recovery
technologies.

Reverse
osmosis
often
has
a
higher
capital
cost
than
does
ion
exchange
when
both
technologies
include
an
electrolytic
recovery
unit.
When
used
for
water
recycling,
reverse
osmosis
and
ion
exchange
both
remove
similar
quantities
of
metals;
however,
reverse
osmosis
may
allow
for
more
water
recycling..
During
reverse
osmosis,
only
the
pumps
use
energy.
In
most
cases,
water
is
recycled;
in
some
cases,
a
closed
loop
is
possible.
Compared
to
ion
exchange,
reverse
osmosis
can
treat
somewhat
higher
feed
stream
concentrations.
The
concentration
of
reverse
osmosis
reject
streams
are
near
or
higher
than
that
of
ion­
exchange
regenerants.
Both
are
less
effective
in
handling
oxidizing
chemistries
or
feed
streams
high
in
organic
compounds
and
total
suspended
solids.
Ion­
exchange
effluent
generally
has
a
lower
TDS
concentration
than
does
reverse
osmosis
permeate
and
can
be
recycled
in
most
rinses.

For
most
applications,
reverse
osmosis
membranes
last
for
one
to
five
years,
although
they
are
susceptible
to
fouling
from
organic
pollutants,
suspended
solids,
or
misuse.
Reverse
osmosis
units
may
be
able
to
track
the
condition
of
the
membrane
by
measuring
the
flux.
If
the
membrane
fouls
or
clogs,
the
flux
rate
drops,
indicating
that
the
membrane
should
be
cleaned.
Labor
associated
with
operating
reverse
osmosis
equipment
is
for
periodic
membrane
cleaning.
Membrane
and
pump
replacement
are
the
primary
maintenance
items.

Best
Management
Practices
and
Environmental
Management
Systems
for
Pollution
Prevention
EPA
encourages
the
wide
spread
use
of
Best
Management
Practices
(
BMPs),
and
Environmental
Management
Systems
(
EMS),
to
achieve
improved
environmental
performance
and
compliance,
pollution
prevention
through
source
reduction,
and
continual
improvement
(
see
EPA
Position
Statement
on
Environmental
Management
Systems,
May
15,
2002,
DCN
17848,
Section
24.4).
However,
as
described
in
the
Section
IV
of
the
preamble
to
the
final
rule,
EPA
is
not
requiring
the
use
of
BMPs
or
EMSs
for
compliance
with
the
MP&
M
effluent
guidelines.

Best
Management
Practices
(
BMPs)
are
inherently
pollution
prevention
practices.
BMPs
may
include
the
universe
of
pollution
prevention
encompassing
production
modifications,
operational
changes,
material
substitution,
materials
and
water
conservation,
and
other
such
measures
(
17).
BMPs
include
methods
to
prevent
the
discharge
of
toxic
and
hazardous
pollutants.
BMPs
are
most
effective
when
organized
into
a
comprehensive
facility
EMS.

MP&
M
facilities
employ
many
types
of
pollution
prevention
measures
including
the
following:
training
and
supervision;
production
planning;
process
or
equipment
modification;
raw
material
and
product
substitution
or
elimination;
loss
prevention
and
housekeeping;
waste
segregation
and
separation;
and
closed­
loop
recycling.
These
practices
are
discussed
in
further
detail
below
(
1).

8­
25
8.3
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
 
Training
and
Supervision
Training
and
supervision
ensure
that
employees
are
aware
of,
understand,
and
support
the
company s
pollution
prevention
goals.
Effective
training
programs
translate
these
goals
into
practical
information
that
enables
employees
to
minimize
waste
generation
by
properly
and
efficiently
using
tools,
supplies,
equipment,
and
materials.

 
Production
Planning
Production
planning
can
minimize
the
number
of
process
operation
steps
and
eliminate
unnecessary
procedures
(
e.
g.,
production
planning
can
eliminate
additional
cleaning
steps
between
process
operations).

 
Process
or
Equipment
Modification
Facilities
can
modify
processes
and
equipment
to
minimize
the
amount
of
waste
generated
(
e.
g.,
changing
rack
configuration
to
reduce
drag­
out).

 
Raw
Material
and
Product
Substitution
or
Elimination
Where
possible,
facilities
should
replace
toxic
or
hazardous
raw
materials
or
products
with
other
materials
that
produce
less
waste
and
less
toxic
waste
(
e.
g.,
replacing
chromium­
bearing
solutions
with
non­
chromium­
bearing
and
less
toxic
solutions,
or
consolidating
types
of
cleaning
solutions
and
machining
coolants).

 
Loss
Prevention
and
Housekeeping
Loss
prevention
and
housekeeping
includes
performing
preventive
maintenance
and
managing
equipment
and
materials
to
minimize
leaks,
spills,
evaporative
losses,
and
other
releases
(
e.
g.,
inspecting
the
integrity
of
tanks
on
a
regular
basis;
using
chemical
analyses
instead
of
elapsed
time
or
number
of
parts
processed
as
the
basis
for
disposal
of
a
solution).

 
Waste
Segregation
and
Separation
Facilities
should
avoid
mixing
different
types
of
wastes
or
mixing
hazardous
wastes
with
nonhazardous
wastes.
Similarly,
facilities
should
not
mix
recyclable
materials
with
noncompatible
materials
or
wastes.
For
example,
facilities
can
segregate
scrap
metal
by
metal
type,
separate
cyanide­
bearing
wastewater
for
preliminary
treatment,
and
segregate
coolants
for
recycling
or
treatment.

 
Closed­
Loop
Recycling
Facilities
can
recover
and
reuse
some
process
streams.
For
example,
some
facilities
can
use
ion
exchange
to
recover
metal
from
electroplating
rinse
water,
reuse
the
rinse
water,
and
reuse
the
regenerant
solution
as
process
solution
make­
up.

8­
26
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
The
following
sections
describe
pollution
prevention
opportunities
for
a
few
MP&
M
facilities.

8.3.1
Pollution
Prevention
for
Cleaning
and
Degreasing
Operations
The
majority
of
facilities
in
the
Oily
Wastes
Subcategory
perform
cleaning
and
degreasing
operations
to
remove
residual
oil
and
coolants
from
metal
parts
following
machining
and
grinding
operations.
These
facilities
also
perform
cleaning
and
degreasing
on
equipment
undergoing
maintenance.
Opportunities
to
reduce
waste
from
these
operations
include
process
elimination,
material
substitution,
in­
process
recycling,
waste
segregation,
maintenance/
housekeeping,
procedures/
scheduling,
and
equipment
layout/
piping/
automation.
Examples
of
these
opportunities
are
presented
below
(
15).

Process
Elimination
 
Determine
whether
parts
need
to
be
cleaned;

 
Use
easy­
to­
clean
or
no­
clean
rust
inhibitors
and
lubricants;

 
Review
the
parts­
handling
process
to
determine
why
parts
are
getting
dirty,
and
take
action
to
prevent
it
from
happening
in
the
future;
and
 
Purchase
clean
input
stock.

Material
Substitution
 
Clean
by
brushing
and
wiping
where
possible;

 
Use
aqueous­
based
cleaners;

 
Use
solvents
with
low
vapor
pressure
and
high
flash
point;
and
 
Use
citrus
or
terpene
cleaners.

In­
Process
Recycling
 
Use
countercurrent
rinsing;

 
Skim/
filter
and
reuse
aqueous
cleaners;

 
Reuse
solvents
by
installing
filtration
or
distillation
units;
and
 
Install
a
bioremediation
parts
washer
that
uses
enzymes
to
remove
oil
and
grease.

8­
27
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Waste
Segregation
 
Segregate
solvents
to
allow
recycling;

 
Keep
solvents
out
of
waste
oil;

 
Keep
fuel,
brake
fluid
and
other
fluids
out
of
solvents
to
prevent
the
mixture
from
becoming
hazardous;
and
 
Keep
solvents
out
of
aqueous
cleaners.

Maintenance/
Housekeeping
 
Use
secondary
containment
for
solvent
storage;
and
 
Implement
a
maintenance
program
to
fix
and
prevent
leaks.

Procedures/
Scheduling
 
Reduce
dragout
by
increasing
drain
time;
and
 
When
dripping
parts,
lift
them
such
that
it
reduces
dragout.

Equipment
Layout/
Piping/
Automation
 
Install
sliding
lids
on
solvent
tanks;

 
Increase
the
freeboard
height
to
significantly
reduce
solvent
evaporation;

 
Install
automatic
parts
lift
on
vapor
degreasers;

 
Use
drain
racks
to
reduce
dragout;
and
 
Drain
parts
using
a
rotating
rack.

8.3.2
Pollution
Prevention
for
Machining
Operations
Many
machining
operations
use
metal­
working
fluids
to
cool
and
lubricate
parts
and
machining
tools
during
cutting,
drilling,
milling,
and
other
machining
operations.
These
fluids
become
contaminated
and
begin
to
lose
their
working
characteristics.
If
neglected,
the
fluids
become
unusable
and
require
treatment
and
disposal.
Through
proper
care,
the
life
span
of
the
fluids
can
be
extended
indefinitely.
For
most
machining
operations,
prolonging
metal­
working
fluid
life
reduces
the
cost
of
treatment
and
disposal,
as
well
as
the
cost
of
fresh
coolant.

Many
MP&
M
facilities
use
some
type
of
pollution
prevention
and
water
conservation
practices
for
machining
wastewaters.
Some
facilities
have
implemented
numerous
pollution
prevention
and
water
conservation
methods
and
technologies
that
result
in
very
low
machining
wastewater
discharge
rates
and
in
some
cases
eliminate
the
discharge
of
machining
fluids.
Pollution
prevention
and
water
conservation
practices
are
applicable
to
all
machining
8­
28
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
operations;
however,
process­
related
factors
and
site­
specific
conditions
may
restrict
the
utility
of
certain
methods.

The
Agency
has
identified
two
categories
of
pollution
prevention
and
water
conservation
practices
and
technologies
that
can
be
used
to
reduce
metal­
working
fluid
discharge:
those
used
to
prevent
metal­
working
fluid
contamination
and
those
used
to
extend
the
life
of
machining
fluids,
including
recovering
and
recycling
metal­
working
fluids.
Within
each
of
these
categories
are
several
specific
practices
and
technologies.
See
Appendix
D
for
more
information
on
these
pollution
prevention
practices.

8.3.3
Painting
Operations
Paint
is
applied
to
a
base
material
for
protective
and
decorative
reasons
in
various
forms,
including
dry
powder,
solvent­
diluted
formulations,
and
water­
borne
formulations.
There
are
various
methods
of
application,
the
most
common
being
immersion
and
spraying.
Water
is
used
in
painting
operations
in
paint
booth
water­
wash
systems
(
water
curtains),
in
water­
borne
formulations,
in
electrophoretic
painting
solutions
and
rinses,
and
in
clean­
up
operations.
This
discussion
is
directed
at
water
use
in
spray
painting
booths;
however,
Appendix
D
also
provides
some
information
on
rinsing
following
electrophoretic
painting
and
water
clean­
up.
EPA
has
identified
three
categories
of
pollution
prevention
and
water
conservation
practices
that,
if
implemented,
can
reduce
or
eliminate
wastewater
discharges
from
painting
operations:
practices
to
reduce
the
quantity
of
paint
entering
the
water
system;
recycling
technologies
for
paint
booth
water;
and
conversion
of
water­
wash
booths
to
dry­
filter
booths.
These
are
discussed
in
this
subsection
and
summarized
in
Appendix
D.
It
is
possible,
however,
that
facilities
can
reduce
or
eliminate
wastewater
discharges
using
different
practices
than
those
described
here.

8.3.4
Pollution
Prevention
for
Printed
Wiring
Board
Manufacturing
Printed
wiring
board
manufacturers
use
a
large
amount
of
water
each
day,
mostly
for
rinsing
and
electroplating
processes.
The
following
BMP s
developed
specifically
for
printed
wiring
board
manufacturing
outline
water­
saving
process
changes
and
controls
that
can
be
inexpensively
incorporated
in
the
production
process.
A
number
of
these
pollution
prevention
processes
are
described
in
more
detail
in
Section
8.1.

 
Use
dry
film
photoresist
instead
of
wet
applications.

 
Examine
the
pre­
plating
rinse
processes:

­
Based
on
monitoring
data,
eliminate
unnecessary
cycles
and
rinse
only
until
desired
cleanliness
is
reached.

­
Switch
from
continuous
to
on­
demand
rinsing,
and
from
once­
through
to
closed­
loop
use.

8­
29
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
­
Use
counter­
current
rinsing.

­
Use
air
or
workpiece
agitation
to
increase
rinsing
efficiency.

­
Spray
rinse
with
high­
pressure,
low
flow
nozzles.
This
can
reduce
rinse
water
use
up
to
60
percent.

­
Link
flow
controls
to
conductivity
meters
that
measure
the
total
dissolved
solids
in
the
rinses.

 
Examine
the
electroplating
process.
Extending
bath
life
will
reduce
both
water
consumption
and
toxics
in
the
effluent.

­
Reduce
drag­
in
through
efficient
rinsing.

­
Use
deionized
or
distilled
water
for
makeup.

­
Reduce
drag­
out
through
the
following
methods:

a)

b)

c)
Minimize
bath
chemical
concentrations.

Use
nonionic
wetting
agents
to
reduce
surface
tension
in
the
process
baths.

Prior
to
rinsing,
maximize
water
returned
to
the
process
bath
through
several
measures
 
withdraw
pieces
from
the
baths
slowly,
install
drainage
boards
between
process
baths
and
rinses
to
return
drag­
out
back
to
the
process
bath,
install
rails
above
process
baths
to
hang
workpiece/
racks
for
drainage
and/
or
use
air
knives
or
spray
rinses
above
process
baths
to
rinse
excess
solution
into
the
process
bath.

­
Restore
barrel
holes.

­
Maintain
bath
solution
quality
through
monitoring,
replacement
of
reagents
and
stabilizers,
and
impurity
removal.

 
Install
multiple
baths
after
the
process
bath
for
using
counter­
current
rinsing
wherever
possible.

8.4
Preliminary
Treatment
of
Segregated
Wastewater
Streams
Preliminary
treatment
systems
reduce
pollutant
loadings
in
segregated
waste
streams
prior
to
combined
end­
of­
pipe
treatment.
Wastewater
containing
pollutants
such
as
8­
30
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
cyanide,
hexavalent
chromium,
oil
and
grease,
or
chelated
metals
may
not
be
treated
effectively
by
chemical
precipitation
and
gravity
settling
without
preliminary
treatment.
Proper
segregation
and
treatment
of
these
streams
is
critical
for
the
successful
treatment
of
process
wastewater.
Highly
concentrated
metal­
bearing
wastewater
also
may
require
pretreatment
to
reduce
metal
concentrations
before
end­
of­
pipe
treatment.
This
subsection
describes
the
following
wastewater
streams
that
typically
undergo
preliminary
treatment
at
MP&
M
facilities:

 
Chromium­
bearing
wastewater;

 
Concentrated
metal­
bearing
wastewater;

 
Cyanide­
bearing
wastewater;

 
Chelated
metal­
bearing
wastewater;
and
 
Oil­
bearing
wastewater.

Table
8­
3
summarizes
these
preliminary
treatment
operations.

8.4.1
Chromium­
Bearing
Wastewater
MP&
M
facilities
generate
hexavalent­
chromium­
bearing
wastewater
from
acid
treatment,
anodizing,
conversion
coating,
and
electroplating
operations
and
rinses.
Hexavalent
chromium
exists
in
an
ionic
form
and
does
not
form
a
metal
hydroxide;
therefore,
hexavalent
chromium
cannot
be
treated
by
chemical
precipitation
and
sedimentation
(
discussed
in
Section
8.5.1).
The
wastewater
requires
preliminary
chemical
treatment
to
reduce
the
hexavalent
chromium
to
trivalent
chromium,
which
can
be
removed
by
chemical
precipitation
and
sedimentation.
As
shown
in
Table
8­
3,
EPA
estimates
there
are
over
1,800
MP&
M
facilities
that
perform
hexavalent
chromium
reduction.
The
chemical
reduction
process
is
discussed
below.
Figure
8­
7
presents
a
diagram
of
a
continuous
chromium
reduction
system.

8­
31
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8­
32
Table
8­
3
MP&
M
Preliminary
and
End­
of­
Pipe
Treatment
Technologies
Technology
Technology
Description
Demonstration
Status
Number
of
Facilities
Visited
Using
the
Technology
a
Number
of
Survey
Facilities
Using
the
Technologyb
Estimated
Number
of
MP&
M
Facilities
Using
the
Technologyc
Chemical
Emulsion
Breaking
Followed
by
Gravity
Oil/
Water
Separation
Adds
acids
(
typically
sulfuric),
polymer,
and
sometimes
alum
to
oil­

bearing
wastewater
to
break
oil/
water
emulsions
for
subsequent
gravity
separation.
Separated
oil
is
skimmed
and
hauled
by
a
contractor.
A
facility
may
purchase
the
recycled
oil
for
reuse.
13
56
958
Chemical
Emulsion
Breaking
Followed
by
Dissolved
Air
Flotation
Adds
acids
(
typically
sulfuric),
polymer,
and
sometimes
alum
to
oil­

bearing
wastewater
to
break
oil/
water
emulsions
for
subsequent
gravity
separation.
Introduces
gas
bubbles
into
the
wastewater,
bringing
oils
and
solids
to
the
surface
for
subsequent
removal.
85
25
244
Chemical
Reduction
of
Hexavalent
Chromium
Reduces
hexavalent
chromium
to
trivalent
chromium
using
a
reducing
agent
such
as
sulfur
dioxide,
sodium
bisulfite,
or
sodium
metabisulfite.
56
103
1,839
Cyanide
Destruction
by
Alkaline
Chlorination
Destroys
cyanide
by
adding
chlorine
(
usually
sodium
hypochlorite
or
chlorine
gas)
to
high
pH
wastewater
to
first
oxidize
cyanide
to
cyanate,

then
cyanate
to
carbon
dioxide
and
nitrogen
gas.
14
53
1,136
Oil
Skimming
of
Oily
Wastewater
Streams
Removes
free
floating
oil
by
gravity
separation
and
mechanical
skimming.
This
technology
does
not
remove
emulsified
oils.
45
89
2,087
Cyanide
Oxidation
by
Ozone
Ozone
oxidizes
cyanide
to
ammonia,
carbon
dioxide
and
oxygen.
0
1
4
Chelation
Breaking/

Precipitation
to
Remove
Complexed
Metals
Wastewater
from
electroless
plating
and
some
cleaning
operations
contains
chelated
metals
that
cannot
be
removed
by
chemical
precipitation.
Strong
reducing
agents
such
as
dithiocarbamate
are
added
to
break
the
metal­
organic
chelate
bond
and
precipitate
the
metal.
15
49
555
Ultrafiltration
Removes
emulsified
or
free­
floating
oils.
This
technology
also
removes
other
solids.
Uses
a
membrane
of
very
small
pore
size.
19
23
351
Activated
Carbon
Adsorption
Removes
dissolved
organic
pollutants
by
filtration
through
and
adsorption
on
activated
carbon.
This
technology
requires
preliminary
treatment
to
remove
suspended
solids
and
oil
and
grease.
9
21
165
Aerobic
Biological
Treatment
Biochemically
decomposes
organic
materials
in
the
presence
of
oxygen
using
microorganisms.
1
(
used
to
treat
nonprocess
wastewater)
4
130
Air
Stripping
Removes
dissolved
volatile
organic
pollutants
by
contacting
the
organics
in
the
wastewater
with
a
continuous
stream
of
air
bubbles.
Volatile
organic
pollutants
are
transferred
from
the
wastewater
to
the
air.
0
2
14
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8­
33
Table
8­
3
(
Continued)

Technology
Technology
Description
Demonstration
Status
Number
of
Facilities
Visited
Using
the
Technology
a
Number
of
Survey
Facilities
Using
the
Technologyb
Estimated
Number
of
MP&
M
Facilities
Using
the
Technologyc
Neutralization
Neutralizes
high
or
low
pH
wastewater
to
within
an
acceptable
range
using
acidic
or
alkaline
chemicals.
Common
acids
include
sulfuric
and
hydrochloric.
Common
alkaline
chemicals
include
lime
and
sodium
hydroxide.
63
233
3,713
Chemical
Precipitation
and
Gravity
Sedimentation
Removes
metals
by
precipitating
insoluble
compounds
such
as
hydroxides,
sulfides,
or
carbonates.
Precipitation
as
metal
hydroxides
using
lime
or
sodium
hydroxide
is
the
most
common.
Precipitated
and
flocculated
solids
are
removed
by
gravity
sedimentation
in
a
clarifier.
149
203
2,981
Chemical
Precipitation
and
Microfiltration
Removes
metals
by
precipitating
insoluble
compounds
such
as
hydroxides,
sulfides,
or
carbonates.
Precipitation
as
metal
hydroxides
using
lime
or
sodium
hydroxide
is
the
most
common.
Precipitated
and
flocculated
solids
are
removed
by
microfiltration
through
a
porous
membrane.
6
5
36
Atmospheric
Evaporation
Includes
both
natural
solar
evaporation
and
forced
atmospheric
evaporation
by
which
the
evaporation
rate
is
accelerated
by
increased
temperature,
air
flow,
and
surface
area.
4
12
142
Ion
Exchange
(
end­
of­
pipe)
Polishing
technique
after
metals
precipitation
to
scavenge
low
concentrations
of
residual
metals
(
cations)
using
combined
cation
and
anion
exchange.
Anions
remain
in
solution
and
are
discharged.

Concentrated
metal­
containing
regenerants
are
typically
returned
to
the
metals
precipitation
system.
17
39
251
Multimedia
Filtration
Removes
solids
from
wastewater
using
filter
media
of
different
grain
size.
Coarser
media
remove
larger
particles
and
finer
media
remove
smaller
particles.
Media
include
garnet,
sand,
and
anthracite
coal.
The
filter
is
periodically
backwashed
to
remove
solids.
12
16
354
Sand
Filtration
Removes
solids
from
wastewater
using
a
sand
filter.
The
filter
is
periodically
backwashed
to
remove
solids.
46
41
830
Gravity
Settling
Physically
removes
suspended
particles
by
gravity.
This
technology
does
not
include
the
addition
of
any
chemicals.
7
46
1,679
Centrifugation
of
Sludge
Separates
water
from
solids
using
centrifugal
force.
Centrifugation
dewaters
sludges,
reducing
the
volume
and
creating
a
semisolid
cake.

Centrifugation
of
sludge
can
typically
achieve
a
sludge
of
20­
35
percent
solids.
7
9
127
Gravity
Thickening
of
Sludge
Physically
separates
solids
and
water
by
gravity.
Gravity
thickening
can
typically
thicken
sludge
to
5
percent
solids.
83
85
1,161
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Table
8­
3
(
Continued)

Technology
Technology
Description
Demonstration
Status
Number
of
Facilities
Visited
Using
the
Technology
a
Number
of
Survey
Facilities
Using
the
Technologyb
Estimated
Number
of
MP&
M
Facilities
Using
the
Technologyc
Pressure
Filtration
of
Sludge
Physically
separates
solids
and
water
by
pressure
filtration.
Most
commonly
performed
in
a
plate­
and­
frame
filter
press
where
the
sludge
builds
up
between
the
filter
plates
and
water
is
filtered
through
a
cloth.

Pressure
filtration
can
produce
a
sludge
cake
with
greater
than
40
percent
solids.
140
189
3,106
Sludge
Drying
Dries
sludge
by
heating,
which
causes
the
water
in
the
sludge
to
evaporate.
28
48
835
Vacuum
Filtration
of
Sludge
Physically
separates
solids
and
water
by
vacuum
filtration.
Most
commonly
performed
in
a
cylindrical
drum
vacuum
filter,
where
water
is
pulled
by
vacuum
through
the
filter
and
dewatered
sludge
is
retained
and
subsequently
scraped
from
the
filter
surface.
Vacuum
filtration
can
produce
a
sludge
cake
with
20
­
30
percent
solids.
11
9
193
8­
34
Source:
MP&
M
site
visits,
MP&
M
sampling
episodes,
MP&
M
surveys
and
technical
literature.
Statistics
specific
to
wastewater­
discharging
facilities.

a
Indicates
the
number
of
MP&
M
facilities
visited
by
EPA
using
the
listed
technology.
EPA
visited
a
total
of
221
facilities.

b
Indicates
the
number
of
water­
discharging
survey
facilities
that
reported
using
this
technology.
Based
on
874
MP&
M
survey
respondents
for
the
1996
detailed
survey
and
the
1989
survey.

c
Indicates
the
estimated
number
of
MP&
M
facilities
currently
performing
this
technology
based
on
the
1989
and
1996
detailed
surveys.
EPA s
national
estimate
of
the
1996
detailed
survey
and
the
1989
survey
includes
approximately
44,000
water­
discharging
facilities.
EPA
estimated
numbers
in
this
column
using
statistical
weighting
factors
for
the
MP&
M
survey
respondents.
See
Section
3.0
for
a
discussion
of
the
development
of
national
estimates
and
statistical
survey
weights.
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Figure
8­
7.
Chemical
Reduction
of
Hexavalent
Chrome
Reduction
is
a
chemical
reaction
in
which
electrons
are
transferred
from
one
chemical
(
the
reducing
agent)
to
the
chemical
being
reduced.
Sulfur
dioxide,
sodium
bisulfite,
sodium
metabisulfite,
peroxide,
and
ferrous
sulfate
form
strong
reducing
agents
in
water.
MP&
M
facilities
use
these
agents
to
reduce
hexavalent
chromium
to
the
trivalent
form,
which
allows
the
metal
to
be
removed
from
solution
by
subsequent
chemical
precipitation.

Sodium
metabisulfite,
sodium
bisulfite,
and
sulfur
dioxide
are
the
most
widely
used
reducing
agents
at
MP&
M
facilities
(
14).
Below
is
an
equation
showing
the
sulfur
dioxide
reaction
(
reduction
using
other
reagents
is
similar
chemically):

(
8­
2)

An
operating
pH
of
between
2
and
3
is
normal
for
chromium
reduction.
At
pH
levels
above
5,
the
reduction
rate
is
slow,
and
oxidizing
agents
such
as
dissolved
oxygen
and
ferric
iron
interfere
with
the
reduction
process
by
consuming
the
reducing
agent.

Typically,
the
chemicals
are
retained
in
a
reaction
tank
for
45
minutes.
The
tank
is
equipped
with
pH
and
oxidation­
reduction
potential
(
ORP)
controls.
Sulfuric
acid
is
added
to
maintain
a
pH
of
approximately
2,
and
a
reducing
agent
is
metered
to
the
reaction
tank
to
maintain
the
target
ORP.

Chemical
reduction
of
hexavalent
chromium
is
a
proven
technology
that
is
widely
used
at
MP&
M
facilities.
Operation
at
ambient
conditions
requires
little
energy,
and
the
process
8­
35
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
is
well
suited
to
automatic
control.
For
high
concentrations
of
chromium,
treatment
chemical
costs
may
be
significant.

Maintenance
of
chemical
reduction
systems
consists
of
sludge
removal,
the
frequency
of
which
depends
on
the
concentration
of
contaminants.
There
also
may
be
small
amounts
of
sludge
generated
due
to
minor
shifts
in
the
solubility
of
the
contaminants
(
e.
g.,
iron
hydroxides).
This
sludge
can
be
removed
by
the
sludge­
handling
equipment
associated
with
subsequent
end­
of­
pipe
chemical
precipitation
and
sedimentation.

8.4.2
Concentrated
Metal­
Bearing
Wastewater
Facilities
use
several
methods
to
manage
concentrated
metal­
bearing
wastewater
from
spent
process
solutions.
Facilities
may:

 
Meter
the
concentrated
metal­
bearing
wastewater
slowly
to
the
end­
of­
pipe
chemical
precipitation
system
and
commingle
it
with
other
facility
wastewater;

 
Treat
the
concentrated
metal­
bearing
wastewater
in
a
batch
pretreatment
system;
or
 
Send
concentrated
metal­
bearing
wastewater
for
off­
site
treatment.

Batch
pretreatment
allows
better
control
of
the
treatment
system
(
e.
g.,
the
treatment
chemicals
can
be
better
tailored
to
the
specific
solution
being
treated),
better
treatment
of
difficult­
to­
treat
materials
(
e.
g.,
photo­
resist­
bearing
wastewater),
and
potential
recovery
of
metals
from
the
sludge.
With
batch
treatment,
facilities
typically
discharge
effluent
from
the
batch
treatment
tank
to
the
end­
of­
pipe
treatment
system
for
additional
polishing.

Batch
chemical
precipitation
of
concentrated
metal­
bearing
wastewater
typically
occurs
in
a
single
stirred
tank,
where
a
precipitating
agent
(
e.
g.,
sodium
hydroxide,
lime,
sodium
sulfide)
is
added
to
create
an
insoluble
metal
hydroxide
or
sulfide
complex.
Following
precipitate
formation,
a
polyelectrolyte
is
added
to
flocculate
the
metal
hydroxide
or
metal
sulfide
particles
into
larger
clumps
that
will
settle
to
the
bottom
of
the
reaction
tank
following
mixing.
Clarified
effluent
from
the
batch
tank
is
discharged
to
the
end­
of­
pipe
treatment
system
and
the
settled
sludge,
typically
containing
only
one
type
of
metal,
is
transferred
off­
site
for
metals
recovery.

8.4.3
Cyanide­
Bearing
Wastewater
Plating
and
cleaning
wastewater
may
contain
significant
amounts
of
cyanide,
which
should
be
removed
through
preliminary
treatment.
In
addition
to
its
toxicity,
cyanide
forms
complexes
with
metals
that
prohibit
subsequent
removal
in
chemical
precipitation
systems.

8­
36
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8­
37
Figure
8­
8.
ide
Destruction
Through
Alkaline
Chlorination
Cyanide
typically
is
treated
using
alkaline
chlorination
with
sodium
hypochlorite
or
chlorine
gas
or
by
ozone
oxidation.
o
processes
are
described
below.

8.4.3.1Alkaline
Chlorination
Alkaline
chlorination
is
in
wide
use
in
industrial
wastewater
treatment
to
destroy
cyanide.
MP&
M
facilities
using
alkaline
chlorination
to
remove
cyanide.
pically
used
as
either
chlorine
gas
or
sodium
hypochlorite
(
i.
e.,
bleach).
idizes
cyanides
to
carbon
dioxide
and
nitrogen
by
the
following
two­
step
chemical
reaction
(
10):

(
8­
3)

(
8­
4)

Figure
8­
8
presents
a
diagram
of
an
alkaline
chlorination
system.

Treatment
equipment
often
consists
of
an
equalization
tank
followed
by
two
continuous
reaction
tanks,
although
the
batch
reaction
can
occur
in
a
single
tank.
an
electronic
controller
to
monitor
and
maintain
the
required
pH
and
ORP.
idize
cyanides
to
cyanates,
chlorine
or
sodium
hypochlorite
is
metered
to
the
first
reaction
tank
as
necessary
to
maintain
the
ORP
at
350
to
400
millivolts,
and
aqueous
sodium
hydroxide
is
added
to
maintain
a
pH
of
approximately
11.
that
most
of
the
cyanide
exists
in
the
CN­
form,
rather
than
as
the
highly
toxic
hydrogen
cyanide
(
HCN)
form.
n
the
second
reaction
tank,
the
ORP
and
the
pH
level
typically
are
maintained
at
600
millivolts
and
8
to
9,
respectively,
to
oxidize
cyanate
to
carbon
dioxide
and
nitrogen.
tank
has
a
chemical
mixer
designed
to
provide
approximately
one
turnover
per
minute.

The
batch
process
typically
occurs
in
two
tanks,
one
to
collect
water
over
a
specified
time
period
and
one
to
treat
an
accumulated
batch.
f
concentrated
wastes
are
Cyan
These
tw
Table
8­
3
shows
there
are
over
1,100
Chlorine
is
ty
The
alkaline
chlorination
process
ox
Each
tank
has
To
ox
This
pH
dictates
I
Each
reaction
I
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
frequently
dumped,
another
tank
may
be
required
to
equalize
the
flow
to
the
treatment
tank.
When
the
holding
tank
is
full,
the
liquid
is
transferred
to
the
reaction
tank
for
treatment.

Alkaline
chlorination
can
take
place
at
ambient
temperature,
can
be
automatically
controlled
at
relatively
low
cost,
and
can
achieve
effluent
concentrations
of
free
cyanide
that
are
below
the
detection
limit.
Disadvantages
include
the
need
for
careful
pH
control,
possible
chemical
interference
in
treating
mixed
wastes,
and
the
potential
hazard
of
storing
and
handling
chlorine
gas
(
if
sodium
hypochlorite
is
not
used).
If
organic
compounds
are
present,
chlorinated
organic
compounds
may
be
generated.
Additionally,
there
are
several
safety
concerns
associated
with
handling
chlorine
gas
and
with
the
gas
feed
system.
This
technology
is
not
effective
in
treating
metallocyanide
complexes,
such
as
ferrocyanide.

8.4.3.2
Ozone
Oxidation
A
less
common
cyanide
treatment
method
is
ozone
oxidation.
Ozone,
generated
as
a
gas,
is
bubbled
through
a
wastewater
solution
containing
free
cyanide.
The
ozone
reacts
with
cyanide,
converting
it
to
cyanate.
Additional
ozone
reacts
with
the
cyanate
to
convert
it
to
nitrogen
gas,
ammonia,
and
bicarbonate,
as
shown
by
the
reactions
below.

CN­
+
O3
­­­­­­­>
CNO­
+
O2
(
8­
5)

3CNO­
+
2O3
+
2OH­
+
2H2
O
­­­­­­­­­­­>
3HCO3
­
+
NH3
+
N2
+
2O2
(
8­
6)

The
reaction
rate
is
limited
by
mass
transfer
of
ozone
to
the
solution,
the
cyanide
concentration,
and
temperature.
Literature
data
show
that
oxidation
can
reduce
amenable
cyanide
in
electroplating
wastewaters
to
below
detection
(
5).
Ozone
is
not
effective
in
treating
metallocyanide
complexes,
such
as
ferrocyanide,
unless
ultraviolet
light
is
added
to
the
reaction
tank
(
6).

One
advantage
ozone
has
over
chlorine
is
the
type
of
residuals
formed.
Chlorine
oxidation
of
organic
compounds
has
the
potential
to
form
trihalomethanes.
Ozone
oxidizes
organic
compounds
to
form
relatively
less
toxic,
short­
chain
organic
acids,
ketones,
and
aldehydes.
Equipment
required
for
ozone
oxidation
of
cyanides
includes
an
ozone
generator,
gas
diffusion
system,
a
mixed
reaction
tank,
and
off­
gas
controls
to
prevent
the
release
of
unreacted
ozone.

The
major
disadvantage
of
the
ozone
oxidation
process
is
the
capital
and
operating
cost
(
12).
Ozone
must
be
manufactured
on­
site
and
delivered
directly
to
the
reaction
tank.
Ozone
generation
equipment
is
expensive,
and
facilities
also
must
purchase
closed
reaction
tanks
and
ozone
off­
gas
treatment
equipment.

8­
38
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.4.4
Chelated­
Metal­
Bearing
Wastewater
Certain
process
wastewaters
evaluated
for
the
final
rule
contain
chelating
agents
that
form
metal
complexes
and
interfere
with
conventional
chemical
precipitation
treatment.
This
wastewater
is
often
associated
with
electroless
plating
and
requires
specific
treatment
for
the
chelated
metals.
In
general,
there
are
three
methods
of
treating
these
wastewaters:

 
Reduction
to
elemental
metal;

 
Precipitation
as
an
insoluble
compound;
and
 
Physical
separation.

8.4.4.1
Reduction
to
Elemental
Metal
Reduction
to
elemental
metal
can
be
done
using
one
of
two
methods.
One
method
is
electrolytic
recovery
(
see
Section
8.2.6),
in
which
the
dissolved
metal
is
deposited
on
a
cathode
for
reclamation
or
disposal.
The
electric
current
provides
the
electrons
to
reduce
the
metal
ion
to
its
elemental
form.
The
reaction
rate
and
achievable
concentration
for
this
technology
depend
on
the
volume
of
wastewater
per
unit
surface
area
of
cathode.
This
method
typically
does
not
lower
metal
concentrations
to
levels
sufficient
for
wastewater
discharge.

The
second
method
uses
a
reducing
agent
to
provide
the
electrons
to
reduce
the
metal.
Possible
reducing
agents
for
treating
chelated
wastewater
streams
include:

 
Dithiocarbamate
(
DTC);

 
Sodium
borohydride;

 
Hydrazine;
and
 
Sodium
hydrosulfite.

Upon
reduction,
the
metal
forms
a
particulate
in
solution,
which
a
solids
removal
technique,
such
as
gravity
clarification,
can
remove.
For
effective
use,
these
reducing
agents
sometimes
require
the
use
of
other
chemicals
(
e.
g.,
lime
or
sodium
hydroxide)
for
pH
adjustment.
Figure
8­
9
presents
a
diagram
showing
this
method
of
chemical
reduction
of
chelated
metals.

8­
39
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Figure
8­
9.
Chemical
Reduction
/
Precipitation
of
Chelated
Metals
8.4.4.2
Precipitation
as
an
Insoluble
Compound
Chelating
agents
hinder
the
formation
of
hydroxides,
making
hydroxide
precipitation
ineffective
for
treating
chelated­
metal­
bearing
wastewaters.
Other
precipitation
methods
that
are
less
affected
by
chelating
agents
include
sulfide
precipitation,
DTC
precipitation,
and
carbonate
precipitation.
Section
8.5.1
discusses
sulfide
precipitation
and
carbonate
precipitation.

DTC
is
added
to
solution
in
stoichiometric
ratio
to
the
metals
present.
Equation
8­
7
shows
the
reduction
of
nickel
using
DTC:

Ni2+
(
aq)
+
DTC2­
(
aq)
 
Ni0
(
s)
(
8­
7)

DTC
is
effective
in
treating
wastewater
containing
chelated
metals.
Based
on
information
provided
in
the
MP&
M
Detailed
Surveys,
approximately
53
percent
of
MP&
M
facilities
with
chelated
metals
use
DTC
for
treatment.
DTC
compounds
are
a
class
of
pesticides
and,
if
used
incorrectly,
may
cause
process
upsets
in
the
biological
treatment
system
used
at
the
POTW
and
can
potentially
be
harmful
to
the
environment
(
e.
g.,
lead
to
fish
kills
if
it
passes
through
the
POTW
and
reaches
surface
waters).
Another
disadvantage
is
that
DTC
precipitation
generates
large
amounts
of
sludge.

Other
treatment
chemicals
used
by
MP&
M
industries
for
treatment
of
chelated
metals
include:

 
Borohydride;

 
Sodium
hydrosulfite;

8­
40
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
 
Sodium
metabisulfite;

 
Polysulfide
polymer;

 
Sodium
hydroxide;

 
Ferrous
sulfate;

 
Ferris
chloride;
and
 
Formaldehyde.

EPA
evaluated
the
treatment
performance
of
polysulfide
polymer
(
Sampling
Episode
6462)
and
determined
this
compound
effectively
treated
chelated
copper
and
nickel
to
metal
finishing
effluent
limits
(
40
CFR
433).
Further
concentration
reductions
may
have
been
achievable
if
additional
jar
testing
was
conducted.
Iron
or
calcium
salts
and
pH
adjustment
may
also
provide
acceptable
methods
for
chelated
metals
treatment;
however,
no
data
are
available
for
evaluation.

The
Orange
County
Sanitation
District
(
OCSD)
compile
a
study
of
a
NDMA
and
found
that
the
highest
concentrations
of
a
probable
human
carcinogen,
n­
nitrosodimethylamine
(
NDMA),
at
a
printed
circuit
board
manufacturer
were
observed
at
effluent
from
batch
treatment
(
18).
 
Overdosing 
of
DTC
in
batch
treatment
systems
may
be
common
and
may
lead
to
the
formation
of
NDMA.
During
its
evaluation
OCSD
encouraged
facilities
and
treatment
chemical
vendors
to
develop
non­
NDMA
forming
treatments.
EPA
compiled
information
on
DTC
alternative
treatments
for
the
record
(
see
 
DTC
Alternatives
for
Treatment
of
Chelated
Metals, 
Section
24.6.1
of
the
rulemaking
record,
DCN
17962).

8.4.4.3
Physical
Separation
Ion
exchange
and
reverse
osmosis
can
separate
metals
from
solution.
These
technologies
are
not
affected
by
chelating
agents
in
the
wastewater,
making
them
effective
in
treating
wastewater
from
electroless
plating.
Sections
8.2.8.1
and
8.2.8.2,
respectively,
discuss
these
technologies.

8.4.5
Oil­
Bearing
Wastewater
Some
MP&
M
wastewater
(
e.
g.,
alkaline
cleaning
wastewater
and
water­
based
metal­
working
fluids)
contains
significant
amounts
of
oil
and
grease.
This
wastewater
sometimes
requires
preliminary
treatment
to
remove
oil
and
grease
and
organic
pollutants.
Oil/
water
separation
includes
breaking
oil/
water
emulsions
(
oil
dispersed
in
water,
stabilized
by
electrical
charges
and
emulsifying
agents)
as
well
as
gravity
separation
of
oil.
When
only
free
oil
(
i.
e.,
nonemulsified
oil)
is
present,
oil
skimming
is
enough
for
effective
treatment.
Techniques
available
to
remove
oil
include
chemical
emulsion
breaking
followed
by
oil/
water
separation
or
dissolved
air
flotation
(
DAF),
oil
skimming,
and
ultrafiltration.
These
technologies
are
described
in
more
detail
below.

Oil/
water
separation
not
only
removes
oil
but
also
removes
organic
compounds
that
are
more
soluble
in
oil
than
in
water.
Subsequent
clarification
removes
organic
solids
8­
41
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
directly
and
may
also
remove
dissolved
organic
compounds
by
adsorption
on
inorganic
solids.
In
MP&
M
operations,
sources
of
these
organic
compounds
mainly
are
process
coolants
and
lubricants,
additives
to
formulations
of
cleaners,
paint
formulations,
or
leaching
from
plastic
lines
and
other
materials.

8.4.5.1
Chemical
Emulsion
Breaking
Chemical
emulsion
breaking
is
used
to
break
stable
oil/
water
emulsions.
A
stable
emulsion
will
not
separate
or
break
down
without
chemical
and
or
physical
treatment.
Chemical
emulsion
breaking
is
applicable
to
wastewater
containing
emulsified
coolants
and
lubricants
such
as
machining
and
grinding
coolants
and
impact
and
pressure
deformation
lubricants.
This
technology
also
is
applicable
to
cleaning
solutions
that
contain
emulsified
oils.
Figure
8­
10
shows
a
diagram
of
a
type
of
continuous
chemical
emulsion
breaking
system.

Figure
8­
10.
Continuous
Chemical
Emulsion
Breaking
Unit
with
Coalescing
Plates
Treatment
of
spent
oil/
water
emulsions
involves
adding
chemicals
to
break
the
emulsion
followed
by
oil/
water
separation.
The
major
equipment
required
for
chemical
emulsion
breaking
includes
reaction
chambers
with
agitators,
chemical
storage
tanks,
chemical
feed
systems,
pumps,
and
piping.
Factors
to
be
considered
for
breaking
emulsions
are
type
of
chemicals,
dosage
and
sequence
of
addition,
pH,
mixing,
heating
requirements,
and
retention
time.

Chemicals
(
e.
g.,
polymers,
alum,
ferric
chloride,
and
organic
emulsion
breakers)
break
emulsions
and
allow
coagulation
(
13)
by
neutralizing
repulsive
charges
between
particles,
precipitating
or
salting
out
emulsifying
agents,
or
weakening
the
interfacial
film
between
the
oil
8­
42
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
and
water
so
it
is
readily
broken.
Reactive
cations
(
e.
g.,
H+
,
Al+
3
,
Fe+
3
)
and
cationic
polymers
are
particularly
effective
in
breaking
dilute
oil/
water
emulsions.
Once
the
charges
are
neutralized
or
the
interfacial
film
broken,
the
small
oil
droplets
and
suspended
solids
either
adsorb
on
the
surface
of
the
floc
that
is
formed,
or
break
out
and
float
to
the
top.
Different
types
of
emulsion­
breaking
chemicals
are
used
for
different
types
of
oils.
If
more
than
one
chemical
is
required,
the
sequence
of
adding
the
chemicals
can
affect
both
breaking
efficiency
and
chemical
dosages.

Another
important
consideration
in
emulsion
breaking
is
pH,
especially
if
cationic
inorganic
chemicals,
such
as
alum,
serve
as
coagulants.
For
example,
a
pH
of
between
2
and
4
keeps
the
aluminum
ion
in
its
most
positive
state
where
it
most
effectively
neutralizes
charges.
After
some
of
the
oil
is
broken
free
and
skimmed,
raising
the
pH
into
the
6­
to­
8
range
with
lime
or
caustic
causes
the
aluminum
to
hydrolyze
and
precipitate
as
aluminum
hydroxide.
This
floc
entraps
or
adsorbs
destabilized
oil
droplets,
which
can
then
be
separated
from
the
water.
Cationic
polymers
can
break
emulsions
over
a
wider
pH
range
and
thus
avoid
acid
corrosion
and
the
additional
sludge
generated
from
neutralization;
however,
this
process
usually
requires
adding
an
inorganic
flocculent
to
supplement
the
adsorptive
properties
of
the
polymer
emulsion
breaker.

Mixing
is
important
in
effectively
breaking
oil/
water
emulsions
because
it
provides
proper
chemical
feed
and
dispersion.
Mixing
also
causes
droplets
to
collide
and
break
the
emulsion
and
promotes
subsequent
agglomeration
into
larger
droplets.
Heating
also
improves
chemical
emulsion
breaking
by
lowering
the
viscosity
and
increasing
the
apparent
specific
gravity
differential
between
oil
and
water.
In
addition,
heating
increases
the
frequency
of
droplet
collisions,
which
helps
to
rupture
the
interfacial
film.

Once
an
emulsion
is
broken,
the
oil
floats
to
the
surface
of
the
water
because
of
the
difference
in
specific
gravity
between
oil
and
water.
Solids
usually
form
a
layer
between
the
oil
and
water
because
some
solids
become
suspended
in
the
oil.
The
longer
the
retention
time,
the
more
complete
the
separation
between
the
oil,
solids,
and
water.
Oils
and
solids
typically
are
skimmed
from
the
surface
of
the
water
after
chemical
emulsion
breaking.
Often,
other
techniques
such
as
air
flotation
or
rotational
separation
(
e.
g.,
centrifugation)
enhance
separation
after
chemical
emulsion
breaking.

The
advantages
of
chemical
emulsion
breaking
are
the
high
removal
efficiency
potential
and
the
possibility
of
reclaiming
the
oily
waste.
Disadvantages
include
corrosion
problems
associated
with
acid­
alum
systems,
operator
training
requirements
for
batch
treatment,
chemical
sludges
produced,
and
poor
efficiency
for
low
oil
concentrations.

Chemical
emulsion
breaking
is
a
very
reliable
process.
The
main
control
parameters
are
pH
and
temperature.
Some
MP&
M
facilities
may
achieve
effective
emulsion
breaking
by
lowering
the
pH
with
acid,
by
heating
the
wastewater,
or
both.
Maintenance
is
required
on
pumps,
mixers,
instrumentation
and
valves,
as
is
periodic
cleaning
of
the
treatment
tank
to
remove
any
accumulated
solids.
Energy
use
typically
is
limited
to
mixers
and
pumps,
but
8­
43
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
also
can
include
heating.
Solid
wastes
generated
by
chemical
emulsion
breaking
include
surface
oil
and
oily
sludge,
which
are
usually
contract
hauled
for
disposal
by
a
licensed
contractor.
If
the
recovered
oil
contains
a
low
enough
percentage
of
water,
it
may
be
burned
for
its
fuel
value
or
processed
and
reused.

8.4.5.2
Oil
Skimming
Oil
skimming
is
a
physical
separation
technology
that
removes
free
or
floating
oil
from
wastewater
using
the
difference
in
specific
gravity
between
oil
and
water.
Common
separation
devices
include
belts,
rotating
drums,
disks,
and
weir
oil
skimmers
and
coalescers.
These
devices
are
not
suited
to
remove
emulsified
oil,
which
requires
chemical
treatment,
ultrafiltration,
or
other
treatment.
Figures
8­
11a
and
8­
11b
show
diagrams
of
disk
and
belt
oil
skimming
units,
respectively,
that
are
applicable
for
small
systems
or
on
process
tanks.
The
oil
removal
system
shown
in
Figure
8­
10
is
a
coalescing
separator
used
for
large
systems.

Figure
8­
11a.
Disk
Oil
Skimming
Unit
8­
44
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Figure
8­
11b.
Belt
Oil
Skimming
Unit
To
separate
oil
from
process
solutions,
oil
skimming
devices
typically
mount
onto
the
side
of
a
tank
and
operate
on
a
continuous
basis.
The
disk
skimmer
is
a
vertically
rotating
disk
that
is
partially
submerged
in
the
solution
(
see
Figure
8­
11a).
The
disk
continuously
revolves
between
spring­
loaded
wiper
blades
that
are
located
above
the
liquid
surface.
The
disk s
adhesive
characteristics
cause
the
floating
oil
to
remain
on
the
disk.
As
the
disk s
surface
passes
under
the
wiper
blades,
the
blades
scrape
off
the
oil,
which
is
diverted
to
a
run­
off
spout
for
collection.
Belt
and
drum
skimmers
operate
in
a
similar
manner,
with
either
a
continuous
belt
or
drum
rotating
partially
submerged
in
a
tank.
As
the
surface
of
the
belt
or
drum
emerges
from
the
liquid,
the
oil
that
adheres
to
the
surface
is
scraped
off
(
drum)
or
squeezed
off
(
belt)
and
diverted
to
a
collection
vessel.
The
oil
typically
is
hauled
off­
site
for
disposal.

Gravity
separators
use
overflow
and
underflow
weirs
to
skim
a
floating
oil
layer
from
the
surface
of
the
wastewater.
The
oil
layer
flows
over
the
weir
into
a
trough
for
disposal
or
reuse
while
most
of
the
water
flows
underneath
the
weir.
A
diffusion
device,
such
as
a
vertical
slot
weir,
helps
create
a
uniform
flow
through
the
system
and
increase
oil
removal
efficiency.

An
oil
skimmer s
removal
efficiency
depends
on
the
composition
of
the
waste
stream
and
the
retention
time
of
the
water
in
the
tank.
Larger,
more
buoyant
particles
require
less
retention
time
than
do
smaller
particles.
The
retention
time
necessary
for
phase
separation
and
subsequent
skimming
varies
from
1
to
15
minutes,
depending
on
the
wastewater
characteristics.
Gravity­
type
separators
tend
to
be
more
effective
for
wastewater
streams
with
consistently
large
8­
45
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
amounts
of
surface
oil.
Drum
and
belt
type
skimmers
are
more
applicable
to
waste
streams
containing
smaller
amounts
of
floating
oil.
A
gravity
separator
in
conjunction
with
a
drum­
type
skimmer
effectively
removes
floating
contaminants
from
nonemulsified
oily
waste
streams.

Coalescers
remove
oil
droplets
too
finely
dispersed
for
conventional
gravity
separation­
skimming
technology.
Coalescing
also
reduces
the
residence
times
(
and
therefore
separator
sizes)
required
to
separate
oil
from
some
wastes.
The
basic
principle
of
coalescence
involves
the
attraction
of
oil
droplets
to
the
coalescing
medium
(
typically
plates).
The
oil
droplets
accumulate
on
the
medium
and
then
rise
to
the
surface
of
the
solution
as
they
combine
to
form
larger
particles.
The
most
important
requirements
for
coalescing
media
are
attraction
for
oil
and
large
surface
area.
Coalescing
media
include
polypropylene,
ceramic,
and
glass.

Coalescing
stages
may
be
integrated
with
a
wide
variety
of
gravity
oil
separators,
and
some
systems
may
incorporate
several
coalescing
stages.
A
preliminary
oil
skimming
step
avoids
overloading
the
coalescer.

8.4.5.3
Flotation
of
Oils
or
Solids
Air
flotation
combined
with
chemical
emulsion
breaking
is
an
effective
way
to
treat
oily
wastewater
containing
low
concentrations
of
metals.
Flotation
separates
oil
and
grease
from
the
wastewater,
and
entrainment
or
adsorption
will
remove
small
amounts
of
metal.
In
DAF,
air
is
injected
into
a
fluid
under
pressure.
The
amount
of
air
that
can
dissolve
in
a
fluid
increases
with
increasing
pressure.
When
the
pressure
is
released,
the
air
comes
out
of
solution
as
bubbles,
which
attach
to
oil
and
grease
molecules
and
 
float 
the
oil
and
grease
to
the
surface.
Induced­
air
flotation
uses
the
same
separation
principles
as
DAF
systems
but
the
gas
is
self­
induced
by
a
rotor­
disperser
mechanism.

Figure
8­
12
shows
a
diagram
of
a
DAF
unit.
A
DAF
system
consists
of
a
pressurizing
pump,
air
injection
equipment,
pressurizing
tank,
a
pressure
release
valve,
and
a
flotation
tank.
DAF
systems
operate
in
two
modes:
full­
flow
pressurization
and
recycle
pressurization.
In
full­
flow
pressurization,
all
influent
wastewater
is
pressurized
and
injected
with
air.
The
wastewater
then
enters
the
flotation
unit
where
the
pressure
is
relieved
and
bubbles
form,
causing
the
oil
and
grease
to
rise
to
the
surface
with
the
air
bubbles.
In
recycle
pressurization,
part
of
the
clarified
effluent
is
recycled
back
to
the
influent
of
the
DAF
unit,
then
pressurized
and
supersaturated
with
air.
The
recycled
effluent
then
flows
through
a
pressure
release
valve
into
the
flotation
unit.
Pressurizing
only
the
recycle
reduces
the
amount
of
energy
required
to
pressurize
the
entire
influent.
DAF
is
the
most
common
method
of
air
flotation.

8­
46
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Figure
8­
12.
Dissolved
Air
Flotation
Unit
8.4.5.4
Ultrafiltration
Ultrafiltration
is
a
membrane­
based
process
used
to
separate
solution
components
based
on
molecular
size
and
shape.
Under
pressure,
solvent
and
small
solute
species
pass
through
the
membrane
and
are
collected
as
permeate
while
the
membrane
retains
larger
compounds,
which
are
recovered
as
concentrate.
Figure
8­
5
shows
a
typical
membrane
filtration
unit.

Ultrafiltration
typically
removes
materials
ranging
from
0.002
to
0.2
microns
or
molecular­
weights
from
500
to
300,000.
It
can
be
used
to
treat
oily
wastewater.
Filtering
the
ultrafiltration
influent
removes
large
particles
and
free
oil
to
prevent
membrane
damage
and
fouling.
Most
ultrafiltration
membranes
consist
of
homogeneous
polymer
or
copolymer
material.
The
transmembrane
pressure
required
for
ultrafiltration
depends
on
membrane
pore
size,
and
typically
ranges
between
15
to
200
psi.

Ultrafiltration
typically
produces
a
concentrated
oil
phase
that
is
two
to
five
percent
of
the
influent
volume.
Oily
concentrates
typically
are
hauled
off­
site
or
incinerated,
and
the
permeate
(
water
phase)
can
be
either
treated
further
to
remove
water­
soluble
metals
and
organic
compounds
or
discharged,
depending
on
local
and
state
requirements.

An
ultrafiltration
system
includes:
pumps
and
feed
vessels,
piping
or
tubing,
monitoring
and
control
units
for
temperature,
pressure,
and
flow
rate;
process
and
cleaning
tanks;
and
membranes.
Membranes
are
designed
specifically
to
handle
various
waste
stream
8­
47
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
parameters,
including
temperature,
pH,
and
chemical
compatibility.
There
are
different
types
of
membranes,
including
hollow
fiber,
tubular,
flat
plate,
and
spiral
wound.
The
type
selected
depends
on
the
application.
For
example,
tubular
membranes
commonly
separate
suspended
solids,
whereas
spiral
wound
membranes
separate
oil
from
water.
Ultrafiltration
systems
designed
to
remove
oil
typically
are
more
expensive
than
are
DAF
systems.
Membranes
must
be
cleaned
periodically
to
ensure
effective
treatment.

End­
of­
Pipe
Wastewater
Treatment
and
Sludge­
Handling
Technologies
This
subsection
describes
end­
of­
pipe
technologies
that
MP&
M
facilities
use
for
wastewater
treatment
and
sludge
handling.
Table
8­
3
describes
each
technology
and
lists
the
number
of
MP&
M
facilities
that
use
the
technology.
Section
8.5.1
discusses
metal
removal
by
chemical
precipitation,
Section
8.5.2
discusses
oil
removal
technologies,
Section
8.5.3
discusses
wastewater
polishing
technologies,
and
Section
8.5.4
discusses
sludge­
handling
technologies.

8.5.1
Chemical
Precipitation
for
Metals
Removal
The
most
common
end­
of­
pipe
treatment
technology
used
at
MP&
M
facilities
to
remove
dissolved
metals
is
chemical
precipitation
and
flocculation
followed
by
gravity
clarification.
The
data
in
Table
8­
3
show
there
are
nearly
3,000
MP&
M
facilities
that
use
chemical
precipitation
and
gravity
settling
to
treat
their
metals­
bearing
wastewater.
Some
MP&
M
facilities
use
microfiltration,
filter
press
operations,
centrifuge
operations,
DAF,
and
American
Petroleum
Institute
(
API)
separation
in
place
of
clarification,
but
this
subsection
discusses
only
clarification
and
microfiltration.
The
types
of
equipment
used
for
chemical
precipitation
vary
widely.
Small
batch
operations
can
take
place
in
a
single
tank
that
typically
has
a
conical
bottom
to
permit
removal
of
settled
solids.
Continuous
processes
usually
occur
in
a
series
of
tanks,
including
an
equalization
tank,
a
rapid­
mix
tank
for
dispersing
the
precipitating
chemicals,
and
a
slow­
mix
tank
for
adding
coagulants
and
flocculants
and
for
floc
formation.

For
continuous­
flow
systems,
the
first
tank
in
the
treatment
train
typically
is
the
equalization
tank.
The
flow
equalization
tank
prevents
upsets
in
processing
operations
from
exceeding
the
hydraulic
design
capacity
of
the
treatment
system,
improves
chemical
feed
control,
and
allows
wastewater
neutralization.

Commingled
wastewater
from
the
equalization
tank
enters
the
rapid
mix
tank,
along
with
various
types
of
precipitation
chemicals
added
to
convert
the
soluble
metals
into
insoluble
compounds.
Following
precipitation,
the
wastewater
flows
into
a
flocculation
tank
where
polyelectrolytes
(
polymers)
are
added,
causing
the
precipitated
solids
to
coagulate
into
larger
particles
that
gravity
settling
or
other
separation
techniques
can
remove.

Chemical
precipitation
is
a
highly
reliable
technology
when
properly
monitored
and
controlled.
The
effectiveness
of
this
technology
depends
on
the
types
of
equipment
used
and
numerous
operating
factors,
such
as
the
characteristics
of
the
raw
wastewater,
types
of
treatment
reagents
used,
and
operating
pH.
In
some
cases,
subtle
changes
in
operating
factors
(
e.
g.,
varying
8­
48
8.5
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
the
pH,
altering
chemical
dosage,
or
extending
the
process
reaction
time)
may
sufficiently
improve
the
system s
efficiency.
In
other
cases,
modifications
to
the
treatment
system
are
necessary.
For
example,
some
raw
wastewater
contains
chemicals
that
may
interfere
with
metals
precipitation,
and
may
require
additional,
specialized
treatment
reagents
such
as
ferrous
sulfate,
sodium
hydrosulfate,
aluminum
sulfate,
or
calcium
chloride.
These
chemicals
may
be
added
prior
to
or
during
the
precipitation
process.

Chemical
precipitation
systems
require
routine
maintenance
for
proper
operation.
This
includes:
calibrating
instrumentation
and
cleaning
probes;
maintaining
chemical
pumps
and
mixers
(
inspection,
cleaning,
lubrication,
replacing
seals
and
packing,
replacing
check
valves,
cleaning
strainers);
and
monitoring
tanks
and
sumps
(
inspection,
cleaning,
corrosion
prevention).

There
are
several
basic
methods
of
performing
chemical
precipitation
and
flocculation
and
many
variations
of
each
method.
The
four
most
common
methods
are
described
below.
Figure
8­
13
shows
a
typical
continuous
chemical
precipitation
system.

Figure
8­
13.
Continuous
Chemical
Precipitation
System
with
Lamella
Clarifier
Removing
precipitated
metals
typically
involves
adding
flocculating
agents
or
polymers
to
destabilize
the
hydrodynamic
forces
that
hold
the
particles
in
suspension.
For
a
continuous
treatment
system,
polymer
is
either
added
in­
line
between
the
reaction
tank
and
the
flocculation
tank,
or
in
a
small
rapid
mix
tank
between
the
reaction
tank
and
flocculation
tank.
In
the
flocculation
tank,
the
mixer
is
slowed
to
promote
agglomeration
of
the
particles
until
their
density
is
greater
than
water
and
they
settle
from
solution
in
the
clarifier.

8­
49
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
Hydroxide
Precipitation
Hydroxide
precipitation
is
the
most
common
method
of
removing
metals
from
MP&
M
wastewater.
This
process
typically
consists
of
several
stages.
In
an
initial
tank,
which
is
mechanically
agitated,
alkaline
treatment
reagents
such
as
lime
(
calcium
hydroxide
or
hydrated
lime),
sodium
hydroxide,
or
magnesium
hydroxide
are
added
to
the
wastewater
to
precipitate
metal
ions
as
metal
hydroxides.
The
reaction
for
precipitation
of
a
divalent
metal
using
sodium
hydroxide
is
shown
in
the
following
equation:

(
8­
8)

The
precipitation
process
usually
operates
at
a
pH
of
between
8.5
and
11,
depending
on
the
types
of
metals
in
the
wastewater.
The
pH
set
point
for
each
hydroxide
precipitation
system
is
determined
by
jar
testing.
Jar
testing
results
determine
the
optimum
pH,
flocculent
type
and
dosage
to
maximize
the
removal
of
target
metals.
Figure
8­
14
shows
the
effect
of
pH
on
hydroxide
precipitation.
Figure
8­
14
was
developed
based
on
empirical
studies
using
single
metal
solutions
in
reagent­
free
water.
However,
metal
solubilities
in
complex
wastewater
may
differ
from
those
shown
in
the
figure,
and
therefore
facilities
must
test
their
actual
wastewater
to
define
the
minimum
solubility
for
all
metals.

Iron
Coprecipitation
Iron
coprecipitation
is
one
method
that
has
proven
effective
at
reducing
the
concentration
of
metals
such
as
arsenic,
beryllium,
cadmium,
copper,
lead,
nickel
and
zinc
to
less
than
could
be
achieved
with
hydroxide
precipitation
alone
(
7).
Iron
coprecipitation
involves
adding
an
iron
source
such
as
ferric
sulfate
or
ferric
chloride
to
the
pH
adjustment
tank
in
the
chemical
precipitation
treatment
system.
Iron
is
then
precipitated
as
iron
oxyhydroxide
(
7).
During
this
process,
other
metal
hydroxides
(
e.
g.,
nickel
hydroxide,
copper
hydroxide)
may
be
incorporated
as
an
impurity
within
the
iron
oxyhydroxide
matrix
or
physically
entrapped
within
its
pore
spaces.
Metal
hydroxides
may
also
be
adsorbed
to
the
surface
of
the
iron
oxyhydroxide
precipitate.
Factors
affecting
the
iron
coprecipitation
process
include
iron
dose
and
iron
oxidation
state,
pH,
the
target
metals
oxidation
state,
the
initial
concentration
of
the
target
metal,
and
competition
for
adsorbent
sites
from
other
species.
Facilities
should
conduct
jar
testing
using
their
actual
wastewater
to
optimize
the
operating
conditions
for
this
process.

Sulfide
Precipitation
The
sulfide
precipitation
process
uses
equipment
similar
to
that
used
for
hydroxide
precipitation.
The
major
difference
between
the
two
processes
is
the
treatment
reagents
used.
Sulfide
precipitation
uses
either
soluble
sulfides
(
e.
g.,
hydrogen
sulfide
or
sodium
sulfide)
or
insoluble
sulfides
(
e.
g.,
ferrous
sulfide)
in
place
of
alkali
reagents
used
in
hydroxide
precipitation.
The
sulfide
reagents
precipitate
dissolved
metals
as
metal
sulfides,
which
often
have
lower
solubility
limits
than
metal
hydroxides.
Therefore,
the
sulfide
precipitation
process
8­
50
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
can
(
for
many
metals)
achieve
lower
levels
of
residual
dissolved
metal
in
the
effluent
than
hydroxide
precipitation
treatment
(
see
Figure
8­
14).
The
sulfide
precipitation
reaction
is
shown
in
the
following
equation:

(
8­
9)

Figure
8­
14.
Effect
of
pH
on
Hydroxide
and
Sulfide
Precipitation
(
10)

Unlike
hydroxides,
sulfide
can
precipitate
most
chelated
metals
and
can
remove
hexavalent
chromium
without
first
reducing
the
chromium
to
its
trivalent
state.

The
major
disadvantages
of
sulfide
precipitation
as
compared
to
hydroxide
precipitation
are
higher
capital
and
operating
costs.
Additional
disadvantages
of
sulfide
8­
51
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
precipitation
are
the
potential
for
toxic
hydrogen
sulfide
gas
generation
and
excessive
sulfide
releases
in
the
effluent,
and
the
generation
of
sulfide
odors.

Carbonate
Precipitation
Carbonate
precipitation
typically
uses
sodium
carbonate
(
soda
ash),
sodium
bicarbonate,
or
calcium
carbonate
to
form
insoluble
metal
carbonates.
The
reaction
is
shown
in
the
following
equation:

(
8­
10)

Carbonate
precipitation
is
similar
in
operation
to
hydroxide
precipitation,
and
its
purpose
is
to
remove
metals
such
as
cadmium
or
lead.
For
these
metals,
carbonate
precipitation
operates
at
a
lower
pH
to
achieve
effluent
concentrations
similar
to
those
achieved
by
hydroxide
precipitation.
Facilities
sometimes
operate
carbonate
precipitation
in
conjunction
with
hydroxide
precipitation,
which
may
improve
the
overall
performance
of
certain
systems.

Carbonate
precipitation
is
less
common
than
hydroxide
precipitation
due
to
the
higher
cost
of
treatment
reagents
and
certain
operational
problems,
such
as
the
release
of
carbon
dioxide,
which
can
result
in
foaming
and
floating
sludge.
Also,
because
many
metal
carbonates
are
more
soluble
than
are
sulfides
or
hydroxides,
this
process
does
not
effectively
precipitate
all
target
metals.

Chemical
Precipitation
Performance
Factors
Ionic
strength
of
the
wastewater
is
another
factor
that
can
negatively
affect
the
performance
of
the
chemical
precipitation
system
(
8).
As
MP&
M
facilities
lower
water
usage
by
implementing
technologies
such
as
flow
restrictors,
countercurrent
cascade
rinsing,
and
timed
rinses,
the
ionic
strength
of
the
wastewater
reaching
the
treatment
system
will
increase.
In
process
chemistry,
a
precipitate
always
forms
or
dissolves
in
the
presence
of
indifferent
electrolytes.
Although
ions
from
such
species
do
not
participate
directly
in
the
solubility
equilibrium
reaction,
they
do
affect
the
solubility
behavior
of
the
precipitate.
The
following
chemical
equilibrium
equations
show
the
impact
of
ionic
strength
on
the
precipitation
process:

CA(
s)
 
C(
aq)
+
A(
aq)
(
8­
11)

The
equilibrium
constant
expression
for
this
reaction
is
given
by
(
Ka
)
eq
=
(
C)(
A)
(
8­
12)

or
(
Ka
)
eq
=
gm
[
C]
gm
[
A]
(
8­
13)

8­
52
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
This
equation
can
be
rewritten
as
(
Ke
)
eq
=
(
Ka
)
eq
/
(
gm
)
2
(
8­
14)

The
greater
the
concentration
of
indifferent
electrolytes,
the
greater
the
ionic
strength
of
the
solution
and
the
smaller
the
value
of
the
activity
coefficient.
In
process
chemistry,
the
value
of
g
is
normally
less
than
1.0.
Therefore,
the
smaller
the
value
of
g,
the
larger
the
value
of
(
Ke
)
eq
,
indicating
the
solubility
of
the
solid
phase
(
metal
hydroxide
precipitate)
will
increase.
This
means
that
the
solubility
of
a
precipitate
will
increase
if
the
concentration
of
indifferent
electrolytes
in
solution
increases
(
8).
MP&
M
facilities
that
reduce
process
water
usage
should
be
aware
of
these
equilibria
changes
that
will
occur
within
their
treatment
system.
Facilities
should
conduct
additional
jar
testing
to
determine
if
they
can
mitigate
the
negative
impacts
with
new
treatment
chemistry
or
add
process
water
to
improve
treatment
efficiency.

One
issue
raised
during
the
MP&
M
public
comment
period
was
that
treatment
system
performance
is
fixed
(
i.
e.,
percent
removal)
and
therefore
the
effluent
concentration
is
a
direct
function
of
influent
concentration.
The
MP&
M
sampling
episode
data,
however,
indicate
the
effluent
concentration
is
a
function
of
the
minimum
solubility
of
the
metal,
regardless
of
the
influent
concentration.
As
explained
in
the
June
2002
NODA
(
67
FR
38779),
EPA
reviewed
graphical
displays
of
the
paired
influent
and
effluent
values
and
other
data
analyses.
Because
the
results
were
inconclusive
and
sometimes
inconsistent,
EPA
was
unable
to
reach
a
conclusion
about
the
effect
of
influent
concentrations
on
the
effluent
concentrations.
If
a
facility
finds
that
influent
concentrations
appear
to
affect
its
effluent
concentrations,
it
may
be
useful
to
perform
jar
testing
on
a
representative
sample
of
wastewater
to
optimize
the
treatment
conditions
for
both
high
and
low
influent
concentrations.

After
precipitation,
the
metal
hydroxide
particles
are
very
fine
and
resistant
to
settling.
To
increase
their
particle
size
and
improve
their
settling
characteristics,
coagulating
and
flocculating
agents
are
added,
usually
in
a
second
tank,
and
slowly
mixed.
Coagulating
and
flocculating
agents
include
inorganic
chemicals
such
as
alum
and
ferric
sulfate,
and
a
highly
diverse
range
of
organic
polyelectrolytes
with
varying
characteristics
suitable
for
different
wastewaters.
The
type
and
dosage
of
flocculent
and
coagulant
are
based
on
the
results
of
jar
testing
done
using
the
actual
facility
wastewater.

Flocculated
particles
with
densities
greater
than
water
settle
in
a
separate
clarification
tank
(
e.
g.,
a
lamella
clarifier),
under
quiescent
conditions.
Operators
remove
the
solids
from
the
bottom
of
the
settling
tank
or
clarifier,
then
transfer
them
to
a
thickener
or
other
dewatering
process
(
see
Section
8.5.4).
Clarifier
effluent
either
undergoes
further
processing
in
a
polishing
unit
such
as
a
multimedia
filter
or
discharges.

8­
53
8.0
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Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.5.1.1
Gravity
Clarification
for
Solids
Removal
Gravity
sedimentation
to
remove
precipitated
metal
hydroxides
is
the
most
common
method
of
clarification
(
solids
removal)
used
by
MP&
M
facilities.
Typically,
two
types
of
sedimentation
devices
are
used:
inclined­
plate
clarifiers
(
e.
g.,
lamella
clarifiers)
and
circular
center­
feed
rim
flow
clarifiers.

Lamella
clarifiers
contain
inclined
plates
oriented
at
angles
varying
between
45
and
60
degrees
from
horizontal.
As
the
water
rises
through
the
clarifier,
the
solids
settle
on
the
plates.
Clarified
effluent
continues
to
the
top
of
the
clarifier,
passes
over
a
weir,
and
collects
in
a
holding
tank.
The
solids
collect
on
the
inclined
plates
and
slide
downward
and
into
the
bottom
of
the
clarifier.
When
sufficient
solids
collect
in
the
bottom
of
the
clarifier,
they
are
scraped
into
a
sludge
hopper
and
then
discharged,
usually
to
a
thickener.
Figure
8­
13
presents
a
lamella
clarifier.

Overflow
rates
for
lamella
clarifiers
(
i.
e.,
between
1,000
and
1,500
gpd/
ft2
for
metal
hydroxide
sludges)
are
two
to
four
times
higher
than
the
overflow
rates
for
clarifiers
not
equipped
with
inclined
plates.
Clarifier
inlets
must
be
designed
to
distribute
flow
uniformly
through
the
tank
and
plate
settlers.
In
addition,
because
solids
can
build
up
on
plate
surfaces
and
adversely
affect
flow
distribution,
the
clarifier
should
be
cleaned
periodically.

Lamella
clarifiers
are
more
common
at
MP&
M
facilities
than
other
types
of
clarifiers
because
of
the
smaller
area
required.
They
typically
require
only
65
to
80
percent
of
the
area
required
for
clarifiers
without
inclined
plates.
Their
design
promotes
laminar
flow
through
the
clarifier,
even
when
the
water
throughput
is
relatively
high.

In
a
center­
feed
rim
flow
clarifier,
wastewater
flows
into
the
bottom
of
a
center
feed
well
and
then
up
into
a
circular
tank.
Heavy
particles
settle
to
the
bottom
of
the
tank
where
they
are
raked
to
a
discharge
pipe
and
removed.
Materials
with
a
density
less
than
the
density
of
water
float
to
the
top
of
the
water
and
are
skimmed
from
the
water
surface
and
discharged
to
a
scum
pit
through
a
scum
trough.
Scum
is
removed
from
the
scum
pit
periodically
and
then
disposed
of.
Clarified
effluent
flows
over
the
top
of
the
clarifier
and
is
collected
in
an
effluent
channel
and
discharged.
Figure
8­
15
shows
a
center­
feed
rim
flow
clarifier.

8­
54
8.0
­
Pollution
Prevention
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Wastewater
Treatment
Technologies
Figure
8­
15.
Center­
Feed
Rim
Flow
Clarifier
8.5.1.2
Microfiltration
for
Solids
Removal
Microfiltration
is
an
alternative
to
conventional
gravity
clarification
after
chemical
precipitation.
Microfiltration
is
a
membrane­
based
process
used
to
separate
small
suspended
particles
based
on
size
and
shape.
Water
and
small
solute
species
pass
under
pressure
through
a
membrane
and
are
collected
as
permeate
while
larger
particles
such
as
precipitated
and
flocculated
metal
hydroxides
are
retained
by
the
membrane
and
are
recovered
as
concentrate.
Microfiltration
is
similar
to
ultrafiltration
(
Section
8.4.5.4)
but
has
a
larger
pore
size.

Microfiltration
removes
materials
ranging
from
0.1
to
1.0
microns
(
e.
g.,
colloidal
particles,
heavy
metal
particulates
and
their
hydroxides).
Most
microfiltration
membranes
consist
of
homogeneous
polymer
material.
The
transmembrane
pressure
required
for
microfiltration
typically
ranges
between
3
to
50
psi,
depending
on
membrane
pore
size.

Microfiltration
produces
a
concentrated
suspended
solid
slurry
that
typically
goes
to
dewatering
equipment
such
as
a
sludge
thickener
or
a
filter
press.
The
permeate
can
either
be
treated
further
to
adjust
the
pH
or
be
discharged,
depending
on
local
and
state
requirements.
Figure
8­
5
shows
a
typical
membrane
filtration
system.

The
microfiltration
system
includes:
pumps
and
feed
vessels;
piping
or
tubing;
monitoring
and
control
units
for
temperature,
pressure,
and
flow
rate;
process
and
cleaning
tanks;
and
membranes.
Membranes
are
designed
specifically
to
handle
various
waste
stream
parameters,
including
temperature,
pH,
and
chemical
compatibility.
Different
types
of
membranes
are
available,
including
hollow
fiber,
tubular,
flat
plate,
and
spiral
wound.
The
configuration
selected
for
a
particular
facility
depends
on
the
type
of
application.
For
example,
tubular
membranes
commonly
separate
suspended
solids,
whereas
spiral
wound
membranes
8­
55
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
separate
oils
from
water.
Microfiltration
is
more
expensive
than
conventional
gravity
clarification.
Membranes
must
be
cleaned
periodically
to
prevent
fouling
and
ensure
effective
treatment.

8.5.1.3
Optimization
of
Existing
Chemical
Precipitation
Treatment
System
Facilities
can
optimize
the
performance
of
an
existing
chemical
precipitation
and
clarification
system
using
a
variety
of
techniques
such
as
adding
equalization
prior
to
treatment,
conducting
jar
testing
to
optimize
treatment
chemistry,
upgrading
control
systems,
and
providing
operator
training.

Equalization
Equalization
is
simply
the
damping
of
flow
and
concentration
variations
to
achieve
a
constant
or
nearly
constant
wastewater
treatment
system
loading
(
8).
Equalization
improves
treatment
performance
by
providing
a
uniform
hydraulic
loading
to
clarification
equipment,
and
by
damping
mass
loadings,
which
improves
chemical
feed
control
and
process
reliability.
MP&
M
facilities
implement
equalization
by
placing
a
large
collection
tank
ahead
of
the
treatment
system.
All
process
water
and
rinse
water
entering
this
tank
are
mixed
mechanically
and
then
pumped
or
allowed
to
gravity
flow
to
the
treatment
system
at
a
constant
rate.
The
size
(
volume)
of
the
tank
depends
on
the
facility
flow
variations
throughout
the
day.
Operating
data
collected
during
MP&
M
sampling
episodes
indicate
hydraulic
residence
times
for
equalization
tanks
average
4
to
6
hours.

Jar
Testing
The
purpose
of
jar
testing
is
to
optimize
treatment
pH,
flocculant
type
and
dosage,
the
need
for
coprecipitants
such
as
iron,
and
solids
removal
characteristics.
Facilities
should
conduct
jar
testing
on
a
sample
of
their
actual
wastewater
to
provide
reliable
information.

Control
System
Upgrades
Typical
treatment
system
controls
at
MP&
M
facilities
includes
pH
and
ORP
controllers
on
alkaline
chlorination
systems
for
cyanide
destruction,
pH
controllers
on
chemical
precipitation
systems,
flow
and
level
monitoring
equipment
on
equalization
tanks,
and
solonoid
valves
and
metering
pumps
on
chemical
feed
systems
to
provide
accurate
treatment
chemical
dosing.
A
number
of
MP&
M
facilities
have
computer
hardware
and
software
to
monitor
and
change
treatment
system
operating
parameters.
For
a
number
of
MP&
M
facilities,
upgrading
control
equipment
may
reduce
both
pH
and
ORP
swings
caused
by
excess
chemical
dosing,
resulting
in
consistent
effluent
metals
concentrations.

8­
56
8.0
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Pollution
Prevention
and
Wastewater
Treatment
Technologies
Operator
Training
Having
operators
trained
in
both
the
theory
and
practical
application
of
wastewater
treatment
is
key
to
ensuring
the
systems
are
operating
at
their
best.
Many
MP&
M
facilities
send
their
operators
to
off­
site
training
centers
while
others
bring
consultants
familiar
with
their
facility s
operations
and
wastewater
treatment
system
to
the
facility
to
train
operators.
Some
of
the
basic
elements
of
an
operator
training
course
should
include
(
1):

 
An
explanation
of
the
need
for
wastewater
treatment,
which
emphasizes
the
benefits
to
employees
and
the
community;

 
An
emphasis
on
management s
commitment
to
environmental
stewardship;

 
An
explanation
of
wastewater
treatment
terminology
in
simple
terms;

 
An
overview
of
the
environmental
regulations
that
govern
the
facility s
wastewater
discharges;

 
A
simple
overview
of
wastewater
treatment
chemistry;

 
Methods
that
can
optimize
treatment
performance
(
e.
g.,
how
to
conduct
jar
testing);

 
The
test
methods
or
parameters
used
to
verify
the
system
is
operating
properly
(
e.
g.,
control
systems);
and
 
The
importance
of
equipment
maintenance
to
ensure
the
system
is
operating
at
its
maximum
potential.

First­
time
training
for
new
operators
may
require
4
to
5
days
of
classroom
and
hands­
on
study.
Experienced
MP&
M
wastewater
treatment
operators
should
consider
attending
at
least
1
day
of
refresher
training
per
year
to
update
themselves
on
the
chemistry
and
to
learn
about
new
equipment
on
the
market
that
may
help
their
system s
performance.

8.5.2
Oil
Removal
Operations
such
as
machining
and
grinding,
disassembly
of
oily
equipment,
and
cleaning
can
generate
wastewater
containing
organic
machining
coolants,
hydraulic
oils,
and
lubricating
oils.
In
addition,
shipbuilding
facilities
may
commingle
oily
bilge
water
with
wastewater
from
other
shore­
side
operations,
resulting
in
a
mixed
oily
wastewater.
Information
collected
during
MP&
M
site
visits,
sampling
episodes,
and
from
the
MP&
M
detailed
surveys
showed
a
variety
of
methods
to
treat
oily
wastewater.
The
primary
treatment
technologies
are
8­
57
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
emulsion
breaking
and
gravity
flotation,
emulsion
breaking
and
DAF,
and
ultrafiltration.
Section
8.4
discusses
these
technologies.

8.5.3
Polishing
Technologies
Polishing
systems
remove
small
amounts
of
pollutants
that
may
remain
in
the
effluent
after
treatment
using
technologies
such
as
chemical
precipitation
and
gravity
clarification.
These
systems
also
can
act
as
a
temporary
measure
to
prevent
pollutant
discharge
should
the
primary
solids
removal
system
fail
due
to
a
process
upset
or
catastrophic
event.
The
following
are
descriptions
of
end­
of­
pipe
polishing
technologies
that
are
applicable
to
MP&
M
facilities.

8.5.3.1
Multimedia
Filtration
Sand
filtration
and
multimedia
filtration
systems
typically
remove
small
amounts
of
suspended
solids
(
metal
precipitates)
entrained
in
effluent
from
gravity
clarifiers.
Sand
and
multimedia
polishing
filters
usually
are
designed
to
remove
90
percent
or
greater
of
all
filterable
suspended
solids
20
microns
or
larger
at
a
maximum
influent
concentration
of
40
mg/
L.
Wastewater
is
pumped
from
a
holding
tank
through
the
filter.
The
principal
design
factor
for
the
filter
is
the
hydraulic
loading.
Typical
hydraulic
loadings
range
between
4
and
5
gpm/
ft2
(
9).
Sand
and
multimedia
filters
are
cleaned
by
backwashing
with
clean
water.
Backwashing
is
timed
to
prevent
breakthrough
of
the
suspended
solids
into
the
effluent.
Figure
8­
16
shows
a
diagram
of
a
multimedia
filtration
system.

Figure
8­
16.
Multimedia
Filtration
System
8­
58
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.5.3.2
Activated
Carbon
Adsorption
Activated
carbon
adsorption
removes
dissolved
organic
compounds
from
wastewater.
Some
MP&
M
facilities
use
carbon
adsorption
to
polish
effluent
from
ultrafiltration
systems
treating
oily
wastewater.
During
adsorption,
molecules
of
a
dissolved
compound
adhere
to
the
surface
of
an
adsorbent
solid.
Activated
carbon
is
an
excellent
adsorption
medium
due
to
its
large
internal
surface
area,
generally
high
attraction
to
organic
pollutants,
and
hydrophobic
nature
(
i.
e.,
water
will
not
occupy
bonding
sites
and
interfere
with
the
adsorption
of
pollutants).
Pollutants
in
the
wastewater
bond
on
the
activated
carbon
grains
until
all
the
surface
bonding
sites
are
occupied.
At
that
point,
the
carbon
is
considered
to
be
 
spent. 
Spent
carbon
requires
regeneration;
regenerated
carbon
has
a
reduced
adsorption
capacity
compared
to
fresh
carbon.
After
several
regenerations,
the
carbon
is
disposed
of.

The
carbon
fits
in
granular
carbon
system
vessels,
forming
a
 
filter 
bed.
Vessels
are
usually
circular
for
pressure
systems
and
rectangular
for
gravity
flow
systems.
For
wastewater
treatment,
activated
carbon
typically
is
packed
into
one
or
more
filter
beds
or
columns;
a
typical
treatment
system
consists
of
multiple
filter
beds
in
series.
Wastewater
flows
through
the
filter
beds
and
comes
in
contact
with
all
portions
of
the
activated
carbon.
The
activated
carbon
in
the
upper
portion
of
the
column
is
spent
first
(
assuming
flow
is
downward),
and
progressively
lower
regions
of
the
column
are
spent
as
the
adsorption
zone
moves
down
the
unit.
When
pollutant
concentrations
at
the
bottom
of
the
column
begin
to
increase
above
acceptable
levels,
the
entire
column
is
considered
spent
and
must
be
regenerated
or
removed.

8.5.3.3
Reverse
Osmosis
Reverse
osmosis
is
a
membrane
separation
technology
used
by
MP&
M
facilities
as
an
in­
process
step
or
as
an
end­
of­
pipe
treatment.
Section
8.2.8.2
discusses
in­
process
reverse
osmosis.
In
an
end­
of­
pipe
application,
reverse
osmosis
typically
recycles
water
and
reduces
discharge
volume
rather
than
recovers
chemicals.
The
effluent
from
a
conventional
treatment
system
generally
has
a
TDS
concentration
unacceptable
for
most
rinsing
operations,
and
cannot
be
recycled.
Reverse
osmosis
with
or
without
some
pretreatment
can
replace
TDS
concentrations,
and
the
resulting
effluent
stream
can
be
used
for
most
rinsing
operations.

8.5.3.4
Ion
Exchange
Ion
exchange
is
both
an
in­
process
metals
recovery
and
recycle
and
end­
of­
pipe
polishing
technology.
Section
8.2.8.1
discusses
in­
process
ion
exchange.
This
technology
generally
uses
cation
resins
to
remove
metals
but
sometimes
uses
both
cation
and
anion
columns.
The
regenerant
from
end­
of­
pipe
ion
exchange
is
not
usually
amenable
to
metals
recovery
as
it
typically
contains
multiple
metals
at
low
concentrations.

8­
59
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.5.4
Sludge
Handling
This
subsection
discusses
the
following
sludge­
handling
technologies:

 
Gravity
thickening;

 
Pressure
filtration;

 
Sludge
drying;
and
 
Vacuum
filtration.

8.5.4.1
Gravity
Thickening
Gravity
thickening
is
a
physical
liquid­
solid
separation
technology
used
to
dewater
wastewater
treatment
sludge.
Sludge
feeds
from
a
primary
settling
tank
or
clarifier
to
a
thickening
tank,
where
gravity
separates
the
supernatant
(
liquid)
from
the
sludge,
increasing
the
sludge
density.
The
supernatant
returns
to
the
primary
settling
tank
or
the
head
of
the
treatment
system
for
further
treatment.
The
thickened
sludge
that
collects
on
the
bottom
of
the
tank
is
pumped
to
additional
dewatering
equipment
or
contract
hauled
for
disposal.
Figure
8­
17
shows
a
diagram
of
a
gravity
thickener.

Figure
8­
17.
Gravity
Thickening
Facilities
where
the
sludge
is
to
be
further
dewatered
by
a
mechanical
device,
such
as
a
filter
press,
generally
use
gravity
thickeners.
Increasing
the
solids
content
in
the
thickener
substantially
reduces
capital
and
operating
costs
of
the
subsequent
dewatering
device
and
also
reduces
the
hauling
cost.
This
process
is
potentially
applicable
to
any
MP&
M
facility
that
generates
sludge.

8­
60
8.0
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Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.5.4.2
Pressure
Filtration
The
filter
press
is
the
most
common
type
of
pressure
filtration
used
at
MP&
M
facilities
for
dewatering
wastewater
treatment
sludges.
A
filter
press
consists
of
a
series
of
parallel
plates
pressed
together
by
a
hydraulic
ram
(
older
models
may
have
a
hand
crank),
with
cavities
between
the
plates.
Figure
8­
18
shows
a
diagram
of
a
plate­
and­
frame
filter
press.
The
filter
press
plates
are
concave
on
each
side
to
form
cavities
and
are
covered
with
a
filter
cloth.
At
the
start
of
a
cycle,
a
hydraulic
pump
clamps
the
plates
tightly
together
and
a
feed
pump
forces
a
sludge
slurry
into
the
cavities
of
the
plates.
The
liquid
(
filtrate)
escapes
through
the
filter
cloth
and
grooves
molded
into
the
plates
and
is
forced
by
the
pressure
of
the
feed
pump
(
typically
around
100
psi)
to
a
discharge
port.
The
filter
cloth
retains
the
solids,
which
remain
in
the
cavities.
This
process
continues
until
the
cavities
are
packed
with
sludge
solids.
Some
units
use
an
air
blow­
down
manifold
at
the
end
of
the
filtration
cycle
to
drain
remaining
liquid
from
the
system,
further
drying
the
sludge.
The
pressure
releases
and
the
plates
separate.
The
sludge
solids
or
cake
is
loosened
from
the
cavities
and
falls
into
a
hopper
or
drum.
A
plate
filter
press
can
produce
a
sludge
cake
with
a
dryness
of
approximately
20
to
30
percent
solids
for
metal
hydroxides
precipitated
with
sodium
hydroxide,
and
30
to
40
percent
solids
for
metal
hydroxides
precipitated
with
calcium
hydroxide.
Filter
presses
are
available
in
a
very
wide
range
of
capacities
(
0.6
ft3
to
20
ft3
).
A
typical
operating
cycle
is
from
4
to
8
hours,
depending
on
the
dewatering
characteristics
of
the
sludge.
Units
are
usually
sized
based
on
one
or
two
cycles
per
day.

Figure
8­
18.
Plate­
and­
Frame
Filter
Press
8­
61
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.5.4.3
Vacuum
Filtration
Some
MP&
M
facilities
conduct
vacuum
filtration
to
reduce
the
water
content
of
metal
hydroxide
sludge.
These
MP&
M
facilities
generally
use
cylindrical
drum
vacuum
filters.
The
filters
on
these
drums
typically
are
either
made
of
natural
or
synthetic
fibers,
or
a
wire­
mesh
fabric.
The
drum
dips
into
a
vat
of
sludge
and
rotates
slowly.
A
vacuum
inside
the
drum
draws
sludge
to
the
filter.
Water
is
drawn
through
the
filter
to
a
discharge
port,
and
the
dewatered
sludge
is
scraped
from
the
filter.
Because
dewatering
sludge
with
a
vacuum
filter
is
relatively
expensive
per
kilogram
of
water
removed,
the
liquid
sludge
is
frequently
gravity­
thickened
prior
to
vacuum
filtration.
Figure
8­
19
shows
a
typical
rotary
vacuum
filter.
Municipal
treatment
plants
and
a
wide
variety
of
industries
frequently
use
vacuum
filters.
Larger
facilities
more
commonly
use
this
technology,
as
they
may
have
a
gravity
thickener
to
double
the
solids
content
of
clarifier
sludge
before
vacuum
filtering.
Often
facilities
apply
a
precoat
to
inhibit
filter
blinding.

Figure
8­
19.
Rotary
Vacuum
Filter
Maintenance
of
vacuum
filters
involves
cleaning
or
replacing
the
filter
media,
drainage
grids,
drainage
piping,
filter
parts,
and
other
parts.
Since
maintenance
time
may
be
as
high
as
20
percent
of
total
operating
time,
facilities
may
maintain
one
or
more
spare
units.
If
this
technology
is
used
intermittently,
the
facility
may
drain
and
wash
the
filter
equipment
each
time
it
is
taken
out
of
service.

8­
62
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.5.4.4
Sludge
Drying
Wastewater
treatment
sludges
are
often
hauled
long
distances
to
disposal
facilities.
The
transportation
and
disposal
costs
depend
mostly
on
the
volume
and
weight
of
sludge,
which
is
directly
related
to
its
water
content.
Therefore,
many
MP&
M
facilities
use
sludge
drying
equipment
following
dewatering
to
further
reduce
the
volume
and
weight
of
the
sludge.
The
solids
content
of
the
sludge
dewatered
on
a
filter
press
usually
ranges
from
20
to
40
percent.
Drying
equipment
can
produce
a
waste
material
with
a
solids
content
of
approximately
90
percent.

There
are
several
design
variations
for
sludge
drying
equipment.
A
commonly
used
system
consists
of
an
auger
or
conveyor
system
to
move
a
thin
layer
of
sludge
through
a
drying
region
and
discharge
it
into
a
hopper.
Various
heat
sources
including
electric,
electric
infrared,
steam,
and
gas
are
used
for
sludge
drying.
Some
continuous
units
are
designed
such
that
the
sludge
cake
discharged
from
a
filter
press
drops
into
the
feed
hopper
of
the
unit,
making
the
overall
dewatering
process
more
automated.
System
capacities
range
from
less
than
1
ft3
/
hr
to
more
than
20
ft3
/
hr
of
feed.
Sludge
drying
equipment
requires
an
air
exhaust
system
due
to
the
fumes
generated
during
drying.

References
1.
Freeman,
H.
M.
Hazardous
Waste
Minimization
.
McGraw­
Hill
Publishing
Co.,
1990,
p.
39.

2.
U.
S.
Environmental
Protection
Agency.
Development
Document
for
Effluent
Limitations
Guidelines
and
Standards
for
the
Nonferrous
Metals
Forming
and
Metal
Powders
Point
Source
Category
.
EPA
440­
1­
86­
019,
September
1996.

3.
Cushnie,
George
C.
Pollution
Prevention
and
Control
Technology
for
Plating
Operations
.
National
Center
for
Manufacturing
Sciences,
1994.

4.
Brown,
T.
and
LeMay,
H.
Chemistry
­
The
Central
Science,
2nd
Edition
.
Prentice­
Hall,
Inc.,
1981,
p.
360.

5.
AFCEC­
TR­
76­
13,
Final
Report:
Ozone
Oxidation
of
Metal
Plating
Cyanide
Wastewater.
September
1976.

6.
Garrison,
R.
L.
and
Monk,
C.
E.
 
Advanced
Ozone­
Oxidation
for
Complexed
Cyanides. 
Proceedings
of
the
First
International
Symposium
on
Ozone
for
Water
and
Wastewater
Treatment,
1973,
p.
551.

7.
Electric
Power
Research
Institute.
Trace
Element
Removal
by
Iron
Adsorption/
Coprecipitator:
Process
Design
Manual
.
EPRI
GS­
7005,
October
1990.

8­
63
8.6
8.0
­
Pollution
Prevention
and
Wastewater
Treatment
Technologies
8.
Benefield,
L.
and
Judkins,
J.
Process
Chemistry
for
Water
and
Wastewater
Treatment
.
Prentice­
Hall,
Inc.,
1982,
p.
110.

9.
Metcalf
&
Eddy,
Inc.
Wastewater
Engineering:
Treatment
Disposal
and
Reuse
.
McGraw­
Hill
Book
Company,
1979,
p.
187.

10.
Freeman,
H.
M.
Standard
Handbook
of
Hazardous
Waste
Treatment
and
Disposal
.
McGraw­
Hill
Publishing
Co.,
1989.

11.
Cherry,
K.
F.
Plating
Waste
Treatment
.
Ann
Arbor
Science,
1982.

12.
Evans,
F.
L.
Ozone
in
Water
and
Wastewater
Treatment
.
Ann
Arbor
Science,
1975.

13.
Harms,
L.
L.
Chemicals
in
the
Water
Treatment
Process
.
Water/
Engineering
and
Management,
March
1987,
pg
32.

14.
Eckenfelder,
W.
W.
Principles
of
Water
Quality
Management
.
CBI
Publishing
Co.,
1980.

15.
Texas
Natural
Resource
Conservation
Commission.
Pollution
Prevention
for
Cleaning
and
Degreasing
Operations
.
www.
eponline.
com
.

16.
Ogunbameru,
G.
Reducing
Water
Used
for
Printed
Circuit
Board
Manufacturing
.
Water
and
Wastewater
Products,
January
2003.
www.
wwp­
online.
com
.

17.
U.
S.
EPA,
Guidance
Document
for
Developing
Best
Management
Practices
(
BMP), 
EPA
833­
B
 
93
 
004,
1993.

18.
NDMA
Source
Control.
Source
Control
Division,
Orange
County
Sanitation
District,
California.
March
27,
2002.
www.
ocsd.
com.

8­
64
9.0
­
Technology
Options
9.0
TECHNOLOGY
OPTIONS
This
section
presents
the
technology
options
evaluated
by
EPA
as
the
basis
for
the
final
MP&
M
effluent
limitations
guidelines
and
standards.
It
also
describes
EPA s
rationale
for
selecting
the
technology
options
for
the
final
rule.
EPA
used
the
options
presented
in
this
section
as
the
basis
for
evaluating
Best
Practicable
Control
Technology
Currently
Available
(
BPT),
Best
Conventional
Pollutant
Control
Technology
(
BCT),
Best
Available
Technology
Economically
Achievable
(
BAT),
New
Source
Performance
Standards
(
NSPS),
Pretreatment
Standards
for
Existing
Sources
(
PSES),
and
Pretreatment
Standards
for
New
Sources
(
PSNS).

EPA
is
promulgating
performance­
based
limitations
and
standards
for
the
Oily
Wastes
Subcategory
to
control
direct
discharges.
These
limitation
and
standards
do
not
require
the
use
of
any
particular
pollution
prevention
or
wastewater
treatment
technology.
Rather,
a
facility
may
use
any
combination
of
pollution
prevention
and
wastewater
treatment
technology
to
comply
with
the
limitations.
Direct
dischargers
must
also
comply
with
NPDES
regulations
(
40
CFR
122).

Section
9.1
summarizes
the
methodology
EPA
used
to
select
the
technologies
included
in
the
options.
Sections
9.2
through
9.9
describe
the
technology
options
evaluated
for
the
final
effluent
limitations
guidelines
and
standards
for
each
subcategory
for
each
of
the
regulatory
levels
of
control.
Section
9.10
summarizes
the
options
for
each
subcategory
considered
and
selected
in
developing
the
effluent
limitations
and
standards,
and
Figures
9­
1
through
9­
6
(
at
the
end
of
this
section)
present
schematic
diagrams
of
the
options.

9.1
Technology
Evaluation
Methods
Facilities
performing
proposed
MP&
M
operations
generate
wastewater
containing
oils,
organic
pollutants,
cyanide,
hexavalent
chromium,
complexed
metals,
and
dissolved
metals.
1
The
technology
options
considered
for
the
final
rule
consist
of
pollution
prevention
and
wastewater
treatment
technologies
designed
to
reduce
or
eliminate
the
generation
or
discharge
of
pollutants
from
facilities
performing
proposed
MP&
M
operations.
EPA
identified
these
technologies
from
responses
to
the
MP&
M
detailed
and
screener
surveys,
MP&
M
site
visits
and
sampling
episodes,
and
technical
literature.
EPA
then
grouped
the
most
common
technologies
according
to
the
type
of
wastewater
treated
(
e.
g.,
oily
wastewater,
metal­
bearing
wastewater,
cyanide­
bearing
wastewater),
and
also
by
source
reduction
and
pollution
prevention
technologies,
recycling
technologies,
and
end­
of­
pipe
treatment
technologies.
Tables
8­
1
through
8­
3
in
Section
8.0
show
the
in­
process
and
end­
of­
pipe
treatment
used
by
industry
as
reported
in
industry
surveys.

1Note:
EPA
evaluated
a
number
of
unit
operations
for
the
May
1995
proposal,
January
2001
proposal,
and
June
2002
NODA
(
see
Tables
4­
3
and
4­
4).
However,
EPA
selected
a
subset
of
these
unit
operations
for
regulation
in
the
final
rule
(
see
Section
1.0).
For
this
section,
the
term
 
proposed
MP&
M
operations 
means
those
operations
evaluated
for
the
two
proposals,
NODA,
and
final
rule.
The
term
 
final
MP&
M
operations 
means
those
operations
defined
as
 
oily
operations 
(
see
Section
1.0,
40
CFR
438.2(
f),
and
Appendix
B
to
Part
438)
and
regulated
by
the
final
rule.

9­
1
9.0
­
Technology
Options
EPA
considered
a
technology
to
be
demonstrated
in
the
industry
if
the
technology
effectively
treated
wastewater
from
proposed
MP&
M
operations
and
if
EPA
observed
the
technology
during
at
least
one
MP&
M
site
visit
or
at
least
one
survey
respondent
reported
using
the
technology.
EPA
evaluated
the
performance
of
each
technology
in
terms
of
percent
removal
and
final
effluent
concentration
using
analytical
data
available
from
MP&
M
sampling
episodes,
discharge
monitoring
reports
and
periodic
compliance
reports,
previous
effluent
guidelines
data
collection
efforts,
and
quantitative
and
qualitative
assessments
from
engineering
site
visits,
comment
submittals,
and
literature.

EPA
evaluated
several
technology
options
for
direct
dischargers
in
the
subcategories
listed
in
the
January
2001
proposal
(
i.
e.,
General
Metals,
Metal
Finishing
Job
Shops,
Printed
Wiring
Board,
Non­
Chromium
Anodizing,
Steel
Forming
and
Finishing,
Oily
Wastes,
Railroad
Line
Maintenance,
and
Shipbuilding
Dry
Dock).

General
Metals
Subcategory
EPA
is
not
revising
or
establishing
any
limitations
or
standards
for
facilities
that
would
have
been
subject
to
this
subcategory.
Such
facilities
will
continue
to
be
regulated
by
the
General
Pretreatment
Standards
(
Part
403),
local
limits,
permit
limits,
and
Parts
413
and/
or
433,
as
applicable.

9.2.1
Best
Practicable
Control
Technology
Currently
Available
(
BPT)

The
following
discussion
describes
the
technology
options
considered
for
the
proposed
General
Metals
Subcategory.
Facilities
in
this
proposed
subcategory
generate
metal­
bearing
wastewater
but
may
also
generate
some
oily
wastewater
(
see
Section
6.0).

Option
1
Option
1
includes
segregation
and
preliminary
treatment
of
oily
wastewater,
cyanide­
bearing
wastewater,
hexavalent
chromium­
bearing
wastewater,
and
complexed
metal­
bearing
wastewater,
followed
by
chemical
precipitation
using
either
sodium
hydroxide
or
lime,
sedimentation
using
a
clarifier,
and
sludge
removal
using
gravity
thickening
and
a
filter
press.
Segregation
of
wastewater
and
subsequent
preliminary
treatment
allows
for
the
most
efficient,
effective,
and
economical
means
of
removing
pollutants
in
certain
wastewater
streams.
These
streams
contain
pollutants
(
e.
g.,
oil
and
grease,
cyanide,
hexavalent
chromium,
chelated
metals,
and
organic
solvents)
that
can
inhibit
the
performance
of
chemical
precipitation
and
sedimentation
treatment,
while
increasing
the
overall
treatment
costs.
For
example,
if
a
facility
segregates
its
oil­
bearing
wastewater
from
its
metal­
bearing
wastewater,
then
the
facility
can
design
an
oil
removal
treatment
technology
based
on
only
the
oily
waste
flow
volume
and
not
on
the
combined
metal­
bearing
and
oil­
bearing
wastewater
flow,
decreasing
the
size
of
the
overall
treatment
system.
Treatment
chemical
costs
are
also
reduced
because
of
the
reduced
volume.
Preliminary
treatment
technologies
for
these
types
of
wastewater
streams
are
described
below.

9­
2
9.2
9.0
­
Technology
Options
(
see
Section
5.0
and
Appendix
C
for
a
more
detailed
description
of
each
of
these
wastewater
streams).

 
Oil­
Bearing
Wastewater.
Alkaline
cleaning
wastewater
and
water­
based
metal­
working
fluids
(
e.
g.,
machining
and
grinding
coolants)
typically
contain
significant
amounts
of
oil
and
grease.
These
wastewater
streams
require
preliminary
treatment
to
remove
oil
and
grease
and
organic
pollutants.
Option
1
includes
a
preliminary
treatment
step
for
these
wastewaters
consisting
of
chemical
emulsion
breaking
followed
by
gravity
separation
of
oil
and
water
(
oil/
water
separator
or
gravity
flotation).

 
Cyanide­
Bearing
Wastewater.
The
industry
generates
several
types
of
wastewater
that
may
contain
significant
amounts
of
cyanide,
such
as
electroplating
and
cleaning
wastewater.
Option
1
includes
a
preliminary
treatment
step
for
these
wastewaters
consisting
of
alkaline
chlorination
with
sodium
hypochlorite.

 
Hexavalent
Chromium­
Bearing
Wastewater.
The
industry
generates
several
types
of
wastewater
that
contain
hexavalent
chromium,
usually
from
acid
treatment,
anodizing,
conversion
coating,
and
electroplating.
Because
hexavalent
chromium
does
not
form
an
insoluble
hydroxide,
this
wastewater
requires
chemical
reduction
of
the
hexavalent
chromium
to
trivalent
chromium
prior
to
chemical
precipitation
and
sedimentation.
Trivalent
chromium
forms
an
insoluble
hydroxide
and
is
treated
by
chemical
precipitation
and
sedimentation.
Option
1
includes
a
preliminary
treatment
step
for
these
wastewaters
consisting
of
chromium
reduction
using
sodium
metabisulfite.

 
Chelated
Metal­
Bearing
Wastewater.
Electroless
plating
and
some
cleaning
operations
generate
wastewater
that
contains
significant
amounts
of
chelated
metals.
This
wastewater
requires
chemical
reduction
to
break
the
metal­
chelate
bond
or
reduce
the
metal­
chelate
complex
to
an
insoluble
state
so
that
it
can
be
removed
during
chemical
precipitation.
Option
1
includes
a
preliminary
treatment
step
for
these
wastewaters
consisting
of
chemical
reduction
using
sodium
borohydride,
dithiocarbamate,
hydrazine,
or
sodium
hydrosulfite.

 
Organic
Solvent­
Bearing
Wastewater.
Option
1
also
includes
contract
hauling
of
solvent
degreasing
wastewater,
where
applicable.
Based
on
the
MP&
M
surveys
and
site
visits,
most
solvent
degreasing
operations
that
use
organic
solvents
(
e.
g.,
1,1,1­
trichloroethane,
trichloroethene)
are
contract
hauled
for
off­
site
recycling.
Some
facilities
performing
proposed
MP&
M
operations
reported
using
organic
solvent/
water
mixtures
or
rinses
9­
3
9.0
­
Technology
Options
following
organic
solvent
degreasing.
EPA
found
contract
hauling
of
this
wastewater
to
be
the
most
common
disposal
method
for
these
sites.

After
pretreatment
of
the
applicable
segregated
streams,
the
Option
1
technology
basis
is
chemical
precipitation
and
gravity
clarification.
Chemical
precipitation
adjusts
the
pH
of
the
wastewater
with
alkaline
chemicals
such
as
lime
(
calcium
hydroxide)
or
caustic
(
sodium
hydroxide)
or
acidic
chemicals
(
such
as
sulfuric
acid)
to
produce
insoluble
metal
hydroxides.
This
step
is
followed
by
a
gravity
settling
process
in
a
clarifier
to
remove
the
precipitated
and
flocculated
metal
hydroxides.
Sludge
is
then
thickened
in
a
gravity­
thickening
unit.
The
sludge
is
then
sent
to
a
filter
press
used
to
remove
excess
wastewater,
which
is
generally
recycled
back
to
the
clarifier.

The
technology
components
that
many
facilities
performing
proposed
MP&
M
operations
currently
use
are
equivalent
to
those
described
for
Option
1.
Differences
in
the
level
of
performance
(
i.
e.,
effluent
limitations)
between
current
discharges
and
Option
1
derive
from
improvements
in
operation
and
control
of
process
operations
and
pollutant
control
technology.
EPA s
technical
database
developed
for
this
rule,
including
industry
survey,
site
visit,
and
sampling
information
collected
during
the
period
from
1989
through
2001,
demonstrate
significant
progress
by
the
industry
in
reducing
pollutants
in
wastewater
discharges
beyond
the
existing
regulatory
standards.
For
example,
sites
are
moving
toward
greater
implementation
of
pollution
prevention
and
water
reduction,
including
progression
to
zero
discharge
when
possible.
In
addition,
improvements
in
treatment
controls
allow
for
more
automated
controls,
which
leads
to
more
consistent
process
operation
and
wastewater
treatment.
Finally,
advances
in
wastewater
treatment
chemicals
also
result
in
higher
treatment
efficiencies.

Option
2
Option
2
builds
on
Option
1
by
adding
the
following
in­
process
pollution
prevention,
recycling,
and
water
conservation
methods
that
allow
for
recovery
and
reuse
of
materials:

 
Two­
stage
countercurrent
cascade
rinsing
for
all
flowing
rinses;

 
Centrifugation
and
recycling
of
painting
water
curtains;
and
 
Centrifugation,
pasteurization,
and
recycling
of
water­
soluble
machining
coolants.

Option
2S
Option
2S
includes
the
technologies
that
compose
Option
2
plus
a
sand
filter
after
the
clarifier
to
further
remove
residual
suspended
solids
from
chemical
precipitation
and
clarification
effluent.

9­
4
9.0
­
Technology
Options
Option
3
In
Option
3,
an
ultrafilter
replaces
the
Option
1
chemical
emulsion
breaking
and
oil/
water
separator
to
remove
oil
and
grease,
and
a
microfilter
replaces
the
Option
1
clarifier.

Option
4
Option
4
includes
the
technologies
in
Option
3
plus
the
in­
process
flow
control
and
pollution
prevention
technologies
described
in
Option
2,
allowing
recovery
and
reuse
of
materials
along
with
water
conservation.

Best
Professional
Judgment
(
BPJ)
to
Part
433
Option
EPA
also
considered
transferring
limitations
from
existing
Metal
Finishing
effluent
guidelines
(
40
CFR
433)
to
the
General
Metals
Subcategory.
The
technology
basis
for
Part
433
includes
the
following:
(
1)
segregation
of
wastewater
streams;
(
2)
preliminary
treatment
steps
as
necessary
(
including
oils
removal
using
chemical
emulsion
breaking
and
oil/
water
separation,
alkaline
chlorination
for
cyanide
destruction,
reduction
of
hexavalent
chromium,
and
chelation
breaking);
(
3)
chemical
precipitation
using
sodium
hydroxide;
(
4)
sedimentation
using
a
clarifier;
and
(
5)
sludge
removal
(
i.
e.,
gravity
thickening
and
filter
press).

Option
Selection
Discussion
As
discussed
in
the
2001
proposal
(
see
66
FR
451),
EPA
dropped
Options
1
and
3
from
further
consideration
because
Options
2
and
4,
respectively,
cost
less
and
provided
greater
pollutant
removals.
After
proposal,
EPA
also
dropped
Option
4
from
further
consideration
for
the
final
rule
because
of
its
increased
cost
and
lack
of
significant
additional
pollutant
removals
beyond
Option
2.
In
addition,
comments
submitted
on
the
proposed
rule
questioned
the
completeness
of
EPA s
database
on
microfiltration
(
Option
4),
noting
that
EPA
transferred
limitations
for
several
pollutants
from
the
Option
2
technology
based
on
lack
of
data.

EPA
dropped
Option
2S
from
further
consideration
for
the
final
rule
for
the
reasons
outlined
in
the
2002
Notice
of
Data
Availability
(
NODA)
(
67
FR
38767).
First,
Option
2S
results
in
greatly
increased
cost
and
minimal
increased
pollutant
removals
beyond
Option
2.
Second,
EPA
believes,
after
incorporating
additional
treatment
performance
data
and
revising
the
statistical
methodology
used
for
calculating
numerical
limitations
(
see
Section
10.0),
the
Option
2
limitations
are
consistently
achievable
without
adding
a
sand
filter.
Therefore,
for
the
final
rule,
EPA
considered
Option
2
and
 
BPJ
to
Part
433
Option 
as
the
basis
for
limitations
for
BPT
for
the
General
Metals
Subcategory.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
removals
for
Option
2.

EPA
proposed
to
establish
BPT
limitations
for
existing
direct
dischargers
in
the
General
Metals
Subcategory
based
on
the
Option
2
technology.
EPA
evaluated
the
cost
of
achieving
effluent
reductions,
pollutant
reductions,
and
the
economic
achievability
of
compliance
9­
5
9.0
­
Technology
Options
with
BPT
limitations
based
on
the
Option
2
technology
and
the
level
of
the
pollutant
reductions
resulting
from
compliance
with
such
limitations.
EPA
has
decided
not
to
establish
BPT
limitations
for
existing
direct
dischargers
in
the
proposed
General
Metals
Subcategory.
The
2001
proposal
also
contains
detailed
discussions
on
why
EPA
rejected
BPT
limitations
based
on
other
BPT
technology
options
(
see
66
FR
452).
The
information
in
the
rulemaking
record
for
the
final
rule
provides
no
basis
for
EPA
to
change
this
conclusion.

Those
facilities
potentially
regulated
in
the
General
Metals
Subcategory
include
facilities
that
are
currently
subject
to
effluent
limitations
guideline
regulation
under
40
CFR
433
as
well
as
facilities
not
currently
subject
to
national
regulation.
Approximately
263
of
the
266
existing
General
Metals
direct
dischargers
(
estimated
from
survey
weights
for
31
surveyed
facilities)
are
currently
covered
by
the
Metal
Finishing
effluent
guidelines
at
Part
433.
The
remaining
three
facilities
(
estimated
from
a
survey
weight
for
one
surveyed
facility)
are
currently
directly
discharging
metal­
bearing
wastewaters
(
e.
g.,
salt
bath
descaling)
but
are
not
covered
by
existing
Metal
Finishing
effluent
guidelines.
EPA s
review
of
discharge
monitoring
data
and
unit
operations
for
this
surveyed
non­
433
General
Metals
facility
(
with
a
survey
weight
of
approximately
three)
indicates
that
this
facility
is
already
achieving
Part
433
limitations
because
this
facility
has
discharges
that
closely
mirror
those
required
by
Part
433.

The
facilities
that
are
currently
subject
to
Part
433
regulations
and
those
facilities
achieving
Part
433
discharge
levels,
in
most
cases,
have
already
installed
effective
pollution
control
technology
that
includes
many
of
the
components
of
the
Option
2
technology.
Approximately
30
percent
of
the
direct
discharging
facilities
in
the
General
Metals
Subcategory
currently
use
chemical
precipitation
followed
by
a
clarifier.
Further,
EPA
estimates
that
compliance
with
BPT
limitations
based
on
the
Option
2
technology
would
result
in
no
closures
of
the
existing
direct
dischargers
in
the
General
Metals
Subcategory.
EPA
also
notes
that
the
adoption
of
this
level
of
control
would
also
reduce
the
pollutants
discharged
into
the
environment
by
facilities
in
this
subcategory.
For
facilities
in
the
General
Metals
Subcategory
at
Option
2,
EPA
estimates
an
annual
compliance
cost
of
$
23.7
million
(
2001$).
Using
the
method
described
in
Section
12.0
to
estimate
baseline
pollutant
loadings,
EPA
estimates
Option
2
pollutant
removals
of
417,477
pounds
of
conventional
pollutants
and
33,716
pounds
of
priority
metal
and
organic
pollutants
from
current
discharges
into
the
Nation s
waters.

Evaluated
under
its
traditional
yardstick,
EPA
calculated
that
the
effluent
reductions
are
achieved
at
a
cost
of
$
18.1/
pound­
pollutant
removed
(
2001$)
for
the
General
Metals
Subcategory
at
Option
2.
To
estimate
all
pounds
of
pollutant
removed
by
Option
2
technology
for
direct
dischargers
in
the
General
Metals
Subcategory,
EPA
used
the
revised
method
described
in
Section
12.0
to
estimate
baseline
pollutant
loadings
as
the
sum
of
chemical
oxygen
demand
(
COD)
pounds
removed
plus
the
sum
of
all
metals
pounds
removed.
EPA
used
the
combination
of
COD
pounds
removed
plus
the
sum
of
all
metals
pounds
removed
to
avoid
any
significant
double
counting
of
pollutants.

As
previously
stated,
EPA
received
many
comments
on
its
estimation
of
baseline
pollutant
loadings
and
reductions
for
the
various
options
presented
in
the
January
2001
proposal.

9­
6
9.0
­
Technology
Options
In
response
to
these
comments,
EPA
solicited
comment
in
the
June
2002
NODA
on
alternative
methods
to
estimate
baseline
pollutant
loadings.
Commentors
on
the
NODA
were
generally
supportive
of
EPA s
alternative
methods
to
estimate
baseline
pollutant
loadings.
In
particular,
commentors
noted
that
more
accurate
estimates
of
baseline
pollutant
loadings
could
be
achieved
by
using
DMR
data.
In
response
to
these
NODA
comments,
EPA
combined
the
alternative
methods
in
the
NODA
into
the
EPA
Costs
&
Loadings
Model
for
the
final
rule
(
see
Sections
11.0
and
12.0).

EPA
also
received
comment
on
the
parameter
or
parameters
it
should
use
for
estimating
total
pounds
removed
by
the
selected
technology
option.
EPA
selected
the
sum
of
COD
and
all
metals
pounds
removed
for
the
final
rule
to
compare
effluent
reductions
and
compliance
costs.
This
approach
avoided
any
significant
double
counting
of
pollutants
and
also
provided
a
reasonable
estimate
of
total
pounds
removed
by
Option
2
for
the
General
Metals
Subcategory.
Option
2
technology
segregates
wastewaters
into
at
least
five
different
waste
streams,
each
of
which
have
one
or
two
treatment
steps.
For
example,
segregated
oily
wastewaters
have
two
treatment
steps
under
Option
2
technology
as
they
are
first
treated
by
chemical
emulsion
breaking­
oil/
water
separation
and
then
by
chemical
precipitation
and
sedimentation.
These
segregated
wastestreams
can
be
loosely
grouped
together
as
either
oily
wastewaters
or
metal­
bearing
wastewaters.
EPA s
use
of
COD
pounds
removed
for
Option
2
technology
generally
represents
the
removal
of
pollutants
from
the
segregated
oily
wastewaters.
EPA s
use
of
total
metals
pounds
removed
for
Option
2
technology
generally
represents
the
removal
of
pollutants
from
the
segregated
metal­
bearing
wastewaters.

EPA
also
considered
alternative
parameters
for
calculating
total
pounds
removed
by
Option
2
for
the
comparison
of
effluent
reductions
and
compliance
costs
for
the
General
Metals
Subcategory.
In
particular,
EPA
calculated
a
ratio
of
less
than
$
14/
pound­
pollutant
removed
(
2001$)
for
the
General
Metals
Subcategory
at
Option
2
when
EPA
used
the
highest
set
of
pollutants
removed
per
facility
with
no
significant
double
counting
of
pollutants
(
i.
e.,
highest
per
facility
pollutant
removals
of:
(
1)
COD
plus
total
metals;
(
2)
oil
and
grease
(
as
HEM)
plus
total
metals;
or
(
3)
oil
and
grease
(
as
HEM)
plus
total
suspended
solids
(
TSS)).
EPA
used
the
highest
per
facility
pollutant
removals
as
a
confirmation
of
its
primary
method
for
calculating
baseline
pollutant
loadings
(
see
Section
12.0)
and
Option
2
for
General
Metals
Subcategory.

Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
June
2002
NODA
and
in
Sections
11.0
and
12.0,
EPA
has
decided
not
to
adopt
BPT
limitations
based
on
Option
2
technology.
A
number
of
factors
supports
EPA s
conclusion
that
BPT
limitations
based
on
Option
2
technology
do
not
represent
effluent
reduction
levels
attainable
by
the
best
practicable
technology
currently
available.
As
previously
noted,
a
substantial
number
of
facilities
that
would
be
subject
to
limitations
as
General
Metals
facilities
are
already
regulated
by
BPT/
BAT
Part
433
limitations
and
other
facilities
are
de
facto
Part
433
facilities
if
characterized
by
their
discharges.
Thus,
establishing
BPT
limitations
for
a
new
General
Metals
Subcategory
would
effectively
revise
existing
BPT/
BAT
limitations
with
respect
to
those
facilities.
In
this
case,
EPA
felt
that
since
the
Agency
is
revising
BPT/
BAT
limitations
for
a
significant
portion
of
an
industry,
it
should
further
review
the
effluent
reductions
achieved,

9­
7
9.0
­
Technology
Options
and
corresponding
costs,
for
Option
2
technology.
Such
an
examination
shows
that,
while
the
Option
2
technology
would
remove
additional
pollutants
at
costs
in
the
middle
of
the
range
EPA
has
traditionally
determined
are
reasonable,
the
costs
of
the
additional
removals
of
toxic
pollutants
are
substantially
greater.
In
developing
the
final
rule,
EPA
determined
that,
where
a
substantial
portion
of
a
subcategory
is
already
subject
to
effluent
limitations
guidelines
that
achieve
significant
removal,
the
Agency
should
not
promulgate
the
proposed
BPT
limitations
because
the
limitations
would
achieve
additional
toxic
removals
at
a
cost
($
1,000/
pound
equivalent
(
PE)
in
1981$)
substantially
greater
than
that
EPA
has
typically
imposed
for
BAT
technology
in
other
industries
(
generally
less
than
$
200/
PE
in
1981$).

EPA
also
considered
transferring
limitations
from
existing
Metal
Finishing
effluent
guidelines
(
40
CFR
433)
to
the
General
Metals
Subcategory.
The
technology
basis
for
Part
433
includes
the
following:
(
1)
segregation
of
wastewater
streams;
(
2)
preliminary
treatment
steps
as
necessary
(
including
oils
removal
using
chemical
emulsion
breaking
and
oil/
water
separation,
alkaline
chlorination
for
cyanide
destruction,
reduction
of
hexavalent
chromium,
and
chelation
breaking);
(
3)
chemical
precipitation
using
sodium
hydroxide;
(
4)
sedimentation
using
a
clarifier;
and
(
5)
sludge
removal
(
i.
e.,
gravity
thickening
and
filter
press).

Approximately
99
percent
of
the
existing
direct
dischargers
in
the
General
Metals
Subcategory
are
currently
covered
by
the
existing
Metal
Finishing
effluent
guidelines.
The
remaining
1
percent
(
an
estimated
three
facilities
nationwide
based
on
the
survey
weight
associated
with
one
surveyed
facility)
are
currently
permitted
to
discharge
metal­
bearing
wastewaters
but
are
not
covered
by
the
existing
Metal
Finishing
effluent
guidelines.
EPA's
review
of
discharge
monitoring
data
and
unit
operations
for
this
surveyed
non­
433
General
Metals
facility
(
with
a
survey
weight
of
approximately
three)
indicates
that
this
facility
is
subject
to
permit
limitations
established
on
a
BPJ
basis
that
are
equivalent
or
more
stringent
than
Part
433
limitations.
Transferring
limitations
from
existing
Metal
Finishing
effluent
guidelines
would
likely
result
in
no
additional
pollutant
load
reductions.
Therefore,
based
on
the
lack
of
additional
pollutant
removals
that
are
estimated,
EPA
is
not
promulgating
BPT
limitations
transferred
from
existing
Metal
Finishing
effluent
limitations
guidelines
for
the
General
Metals
Subcategory.

EPA
is
not
revising
or
establishing
BPT
limitations
for
any
facilities
in
this
subcategory.
Direct
dischargers
in
the
General
Metals
Subcategory
will
remain
regulated
by
permit
limits
and
Part
433,
as
applicable.

9.2.2
Best
Conventional
Pollutant
Control
Technology
(
BCT)

In
deciding
whether
to
adopt
more
stringent
limitations
for
BCT
than
BPT,
EPA
considers
whether
there
are
technologies
that
achieve
greater
removals
of
conventional
pollutants
than
those
adopted
for
BPT,
and
whether
those
technologies
are
cost­
reasonable
under
the
standards
established
by
the
CWA.
EPA
generally
refers
to
the
decision
criteria
as
the
 
BCT
cost
test. 
For
a
more
detailed
description
of
the
BCT
cost
test
and
details
of
EPA s
analysis,
see
Chapter
4
of
the
Economic,
Environmental,
and
Benefits
Analysis
of
the
Final
Metal
Products
&
Machinery
Rule
(
EEBA)
(
EPA­
821­
B­
03­
002).

9­
8
9.0
­
Technology
Options
As
EPA
is
not
establishing
any
BPT
limitations
for
the
General
Metals
Subcategory,
EPA
did
not
evaluate
any
technologies
for
the
final
rule
that
can
achieve
greater
removals
of
conventional
pollutants.
Consequently,
EPA
is
not
establishing
BCT
limitations
for
the
General
Metals
Subcategory.

9.2.3
Best
Available
Technology
Economically
Achievable
(
BAT)

EPA
proposed
to
establish
BAT
limitations
for
existing
direct
dischargers
in
the
General
Metals
Subcategory
based
on
the
Option
2
technology.
As
discussed
in
Section
9.2.1,
EPA
has
decided
not
to
establish
BPT
limitations
based
on
Option
2
technology.
For
the
same
reasons,
EPA
is
not
establishing
BAT
limitations
based
on
the
same
technology.
EPA
evaluated
the
cost
of
effluent
reductions,
pollutant
reductions,
and
the
economic
achievability
of
compliance
with
BAT
limitations
based
on
the
Option
2
technology.

Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
in
Sections
11.0
and
12.0,
EPA
determined
that
the
costs
of
Option
2
are
disproportionate
to
the
toxic
pollutant
reductions
(
measured
in
PE).
The
cost
of
achieving
the
effluent
reduction
(
in
1981$)
for
Option
2
for
direct
dischargers
in
the
General
Metals
Subcategory
is
over
$
1,000/
PE
removed
(
see
the
EEBA
and
Section
26.0
of
the
rulemaking
record,
DCN
37900,
for
a
discussion
of
the
cost­
effectiveness
analysis).
The
costs
associated
with
this
technology
are,
as
previously
noted,
substantially
greater
than
the
level
EPA
has
traditionally
determined
are
associated
with
available
toxic
pollutant
control
technology.
EPA
has
determined
that
Option
2
technology
is
not
the
best
available
technology
economically
achievable
for
existing
direct
dischargers
in
the
General
Metals
Subcategory.
Therefore,
EPA
is
not
revising
or
establishing
BAT
limitations
for
this
subcategory
based
Option
2
technology.

EPA
also
considered
transferring
BAT
limitations
from
existing
Metal
Finishing
effluent
guidelines
(
40
CFR
433.14)
to
the
General
Metals
Subcategory
(
see
 
BPJ
to
Part
433
Option 
in
Section
9.2.1).
EPA
reviewed
existing
General
Metals
facilities
and
found
that
all
are
currently
achieving
Part
433
BAT
limitations.
Transferring
BAT
limitations
from
existing
Metal
Finishing
effluent
guidelines
would
likely
result
in
no
additional
pollutant
load
reductions
and
minimal
incremental
compliance
costs
(
see
Section
9.2.1).
Therefore,
based
on
the
lack
of
additional
pollutant
removals
that
are
estimated,
EPA
is
not
promulgating
BAT
limitations
transferred
from
existing
Metal
Finishing
effluent
limitations
guidelines
for
the
General
Metals
Subcategory.

EPA
is
not
revising
or
establishing
BAT
limitations
for
any
facilities
in
this
subcategory.
Direct
dischargers
in
the
General
Metals
Subcategory
will
remain
regulated
by
permit
limits
and
Part
433,
as
applicable.

9­
9
9.0
­
Technology
Options
9.2.4
New
Source
Performance
Standards
(
NSPS)

EPA
proposed
NSPS
for
the
General
Metals
Subcategory
based
on
Option
4
technology
(
see
Section
9.2.1).
Option
4
technology
is
similar
to
Option
2
(
including
Option
2
flow
control
and
pollution
prevention)
but
includes
oils
removal
using
ultrafiltration
and
solids
separation
by
a
microfilter
(
instead
of
a
clarifier).
Commentors
stated
that
EPA
had
under­
costed
the
Option
4
technology
and
that
the
compliance
costs
would
be
a
barrier
to
entry
for
new
facilities.
In
addition,
commentors
questioned
the
completeness
of
EPA s
database
on
microfiltration,
noting
that
EPA
transferred
standards
for
several
pollutants
from
the
Option
2
technology,
based
on
lack
of
data.
EPA
reviewed
its
database
for
the
Option
4
technology
and
agrees
that
its
microfiltration
database
is
insufficient
to
support
a
determination
that
the
Option
4
limitations
are
technically
achievable.

EPA
also
evaluated
setting
General
Metals
NSPS
based
on
the
Option
2
technology
and
assessed
the
financial
burden
to
new
General
Metals
direct
dischargers.
Specifically,
EPA s
 
barrier­
to­
entry 
analysis
identified
whether
General
Metals
NSPS
based
on
the
Option
2
technology
would
pose
sufficient
financial
burden
as
to
constitute
a
material
barrier
to
entry
of
new
General
Metals
establishments
into
the
MP&
M
Point
Source
Category.
Additionally,
EPA
reviewed
its
database
for
establishing
General
Metals
NSPS
based
on
the
Option
2
technology
as
commentors
indicated
the
proposed
standards
were
not
technically
achievable.

In
response
to
these
comments,
EPA
reviewed
all
the
information
currently
available
on
General
Metals
facilities
employing
Option
2
technology.
This
review
demonstrated
that
process
wastewaters
at
General
Metals
facilities
contain
a
wide
variety
of
metals
in
significant
concentrations.
Commentors
stated
that
single­
stage
precipitation
and
solids
separation
steps
may
not
achieve
sufficient
removals
for
wastewaters
that
contain
significant
concentrations
of
a
wide
variety
of
metals
­
especially
if
the
metals
preferentially
precipitate
at
disparate
pH
ranges.
Consequently,
to
address
concerns
raised
by
commentors,
EPA
also
costed
new
sources
to
operate
two
separate
chemical
precipitation
and
solids
separation
steps
in
series.
Two­
stage
chemical
precipitation
and
solids
separation
allows
General
Metals
facilities
with
multiple
metals
to
control
metal
discharges
to
concentrations
lower
than
single­
stage
chemical
precipitation
and
solids
separation
over
a
wider
pH
range.

Applying
this
revised
costing
approach,
EPA
projects
a
barrier
to
entry
for
General
Metals
NSPS
based
on
the
Option
2
technology
because
14
percent
of
General
Metals
direct
dischargers
have
after­
tax
compliance
costs
between
1
to
3
percent
of
revenue,
22
percent
have
after­
tax
compliance
costs
between
3
to
5
percent
of
revenue,
and
2
percent
have
after­
tax
compliance
costs
greater
than
5
percent
of
revenue.
Consequently,
based
on
the
compliance
costs
of
the
modified
Option
2
technology,
EPA
rejected
Option
2
technology
as
the
basis
for
NSPS
in
the
General
Metals
Subcategory.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

9­
10
9.0
­
Technology
Options
EPA
also
considered
transferring
NSPS
from
existing
Metal
Finishing
effluent
guidelines
(
40
CFR
433.16)
to
the
General
Metals
Subcategory.
EPA
reviewed
existing
General
Metals
direct
dischargers
and
found
that
all
are
currently
either
covered
by
or
have
permits
based
on
the
Metal
Finishing
limitations
at
40
CFR
433.
EPA
has
no
basis
to
conclude
that
new
General
Metals
facilities
would
have
less
stringent
requirements
than
existing
facilities,
particularly
since,
in
the
absence
of
promulgated
NSPS,
it
is
likely
that
permit
writers
would
consult
the
Part
433
requirements
to
establish
BPJ
limits.
In
addition,
those
new
facilities
which
meet
the
applicability
criteria
for
Part
433
will
be
subject
to
the
NSPS
for
that
category.
Therefore,
transferring
standards
from
these
existing
Metal
Finishing
effluent
limitations
guidelines
would
likely
result
in
no
additional
pollutant
load
reductions.

Therefore,
based
on
the
lack
of
additional
pollutant
removals
that
are
estimated,
EPA
is
not
promulgating
NSPS
for
the
General
Metals
Subcategory.
EPA
is
not
revising
or
establishing
NSPS
for
any
facilities
in
this
subcategory.
Direct
dischargers
in
the
General
Metals
Subcategory
will
remain
regulated
by
permit
limits
and
Part
433,
as
applicable.

9.2.5
Pretreatment
Standards
for
Existing
Sources
(
PSES)

As
discussed
in
the
June
2002
NODA
(
67
FR
38798),
EPA
also
considered
a
number
of
alternative
options
whose
economic
impacts
would
be
less
costly
than
Option
2
technology.
These
options
potentially
have
compliance
costs
more
closely
aligned
with
toxic
pollutant
reductions.
EPA
considered
the
following
alternative
options
for
the
final
rule:

 
Option
A:
No
change
in
current
regulation.

 
Option
B:
Option
2
with
a
higher
low­
flow
exclusion.

 
Option
C:
Upgrading
facilities
currently
covered
by
Part
413
to
meet
the
PSES
of
Part
433
( 
413
to
433
Upgrade
Option 
described
below).

 
Option
D:
Upgrading
all
facilities
covered
by
Part
413
and
those
facilities
covered
by
 
local
limits
only 
that
discharge
greater
than
a
specified
wastewater
flow
(
e.
g.,
1,
3,
or
6.25
million
gallons
per
year
(
MGY))
of
process
wastewater
to
meet
the
PSES
of
Part
433
( 
Local
Limits
to
433
Upgrade
Option 
described
below).
Note
that
facilities
regulated
by
 
local
limits
only 
are
also
regulated
by
the
General
Pretreatment
Standards
(
40
CFR
403).

413
to
433
Upgrade
Option
The
413
to
433
Upgrade
Option
would
require
those
facilities
currently
required
to
meet
the
standards
of
the
Electroplating
effluent
limitations
guidelines
(
40
CFR
413)
to
meet
the
limitations
and
standards
of
the
Metal
Finishing
effluent
guidelines
(
40
CFR
433).
Currently,
the
only
facilities
that
are
still
completely
covered
by
the
Electroplating
effluent
guidelines
are
9­
11
9.0
­
Technology
Options
indirect
dischargers
that
were
in
existence
prior
to
1982
and
have
not
significantly
upgraded
their
operations.
Therefore,
this
alternative
option
applies
to
only
a
subset
of
indirect
dischargers
within
the
proposed
General
Metals,
Metal
Finishing
Job
Shops,
Printed
Wiring
Board,
and
Non­
Chromium
Anodizing
Subcategories.

The
technology
components
that
compose
the
basis
for
the
413
to
433
Upgrade
Option
are
equivalent
to
those
described
for
Option
1.
Differences
in
the
level
of
performance
(
i.
e.,
effluent
limitations)
between
the
413
to
433
Upgrade
Option
and
Option
1
derive
from
improvements
in
operation
and
control
of
process
operations
and
pollutant
control
technology
since
the
early
1980s
when
the
Electroplating
effluent
guidelines
were
developed.

Local
Limits
to
433
Upgrade
Option
This
option
would
upgrade
all
facilities
covered
by
Part
413
and
those
facilities
covered
by
 
local
limits
only 
that
discharge
greater
than
a
specified
wastewater
flow
(
e.
g.,
1,
3,
or
6.25
million
gallons
per
year)
of
process
wastewater
to
meet
the
PSES
of
Part
433.
Accordingly,
this
technology
option
applies
to
only
a
subset
of
indirect
dischargers
within
the
proposed
General
Metals
Subcategory.
A
separate
but
similar
alternative
option
(
see
Section
9.2.1)
applies
to
direct
dischargers.

The
technology
components
that
compose
the
basis
for
the
Local
Limits
to
433
Upgrade
Option
are
equivalent
to
those
described
for
Option
1.
Differences
in
treatment
performance
(
i.
e.,
effluent
limitations)
between
the
Local
Limits
to
433
Upgrade
Option
and
Option
1
derive
from
improvements
in
operation
and
control
of
pollutant
control
technology
implemented
since
the
early
1980s
when
the
Electroplating
effluent
guidelines
were
developed.

Option
Selection
Discussion
EPA
proposed
to
establish
PSES
for
existing
indirect
dischargers
in
the
General
Metals
Subcategory
based
on
the
Option
2
technology
(
i.
e.,
the
same
technology
basis
that
EPA
considered
for
BPT/
BCT/
BAT
for
this
subcategory)
with
a
 
low­
flow 
exclusion
of
1
MGY
to
reduce
economic
impacts
on
small
businesses
and
administrative
burden
for
control
authorities.
Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
in
Sections
11.0
and
12.0,
EPA
rejected
promulgating
PSES
for
existing
indirect
dischargers
in
the
General
Metals
Subcategory
based
on
the
Option
2
technology
for
the
following
reasons:
(
1)
many
General
Metals
indirect
dischargers
are
currently
regulated
by
existing
effluent
guidelines
(
Parts
413
or
433
or
both,
as
applicable);
(
2)
EPA
estimates
that
compliance
with
PSES
based
on
the
Option
2
technology
will
result
in
the
closure
of
approximately
4
percent
of
the
existing
indirect
dischargers
in
this
subcategory;
and
(
3)
EPA
determined
that
the
incremental
toxic
pollutant
reductions
are
very
expensive
per
pound
removed
(
the
cost­
effectiveness
value
(
in
1981$)
for
Option
2
for
indirect
dischargers
in
the
General
Metals
Subcategory
is
$
432/
PE).

9­
12
9.0
­
Technology
Options
This
suggests
to
EPA
that
the
identified
technology
is
not
truly
 
available 
to
this
industry
because
it
would
remove
a
relatively
small
number
of
additional
toxic
pounds
at
a
cost
significantly
greater
than
that
EPA
has
typically
determined
is
appropriate
for
other
industries.
Therefore,
EPA
has
determined
that
Option
2
technology
is
not
the
best
available
technology
economically
achievable
for
existing
indirect
dischargers
in
the
General
Metals
Subcategory,
and
is
not
establishing
PSES
for
this
subcategory
based
on
the
Option
2
technology.

Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
in
Sections
11.0
and
12.0,
EPA
has
revised
its
methodology
for
estimating
compliance
costs
and
pollutant
loadings
for
Option
2,
higher
low­
flow
exclusions
(
Option
B),
and
the
 
upgrade 
options
(
Options
C
and
D)
previously
described.
Using
information
from
this
revised
analysis,
EPA
concludes
that
all
of
these
alternative
options
(
Options
B,
C,
and
D)
are
either
not
available
or
not
economically
achievable.
EPA
rejected
Options
B,
C,
and
D
because:
(
1)
more
than
10
percent
of
existing
indirect
dischargers
not
covered
by
Part
433
close
at
the
upgrade
option;
or
(
2)
toxic
removals
of
the
upgrade
options
are
quite
expensive
(
cost­
effectiveness
values
(
in
1981$)
in
excess
of
$
420/
PE),
suggesting
that
these
options
are
not
truly
available
technologies
for
this
industry
segment.

EPA
consequently
determined
that
none
of
the
treatment
options
represented
best
available
technology
economically
achievable.
Therefore,
EPA
is
not
revising
or
establishing
PSES
for
existing
indirect
dischargers
in
the
General
Metals
Subcategory
(
Option
A).
Wastewater
discharges
to
POTWs
from
facilities
in
this
subcategory
will
remain
regulated
by
local
limits,
General
Pretreatment
Standards
(
Part
403),
and
Parts
413
and/
or
433,
as
applicable.
EPA
also
notes
that
facilities
regulated
by
Parts
413
and/
or
433
PSES
must
comply
with
Part
433
PSNS
if
the
changes
to
their
facilities
are
determined
to
make
them
new
sources.

9.2.6
Pretreatment
Standards
for
New
Sources
(
PSNS)

In
2001,
EPA
proposed
pretreatment
standards
for
new
sources
based
on
the
Option
4
technology
basis.
Option
4
technology
is
similar
to
Option
2
(
including
Option
2
flow
control
and
pollution
prevention)
but
includes
oils
removal
using
ultrafiltration
and
solids
separation
by
a
microfilter
(
instead
of
a
clarifier).
As
explained
in
Section
9.2.4,
EPA
concluded
that
its
database
is
insufficient
to
support
a
determination
that
the
Option
4
standards
are
technically
achievable.
As
a
result,
for
the
final
rule,
EPA
considered
establishing
PSNS
in
the
General
Metals
Subcategory
based
on
the
Option
2
technology
(
i.
e.,
the
same
technology
basis
that
was
considered
for
BPT/
BCT/
BAT
for
this
subcategory)
along
with
the
same
 
low­
flow 
exemption
of
1
MGY
considered
for
existing
sources.

For
the
final
rule,
EPA
evaluated
setting
General
Metals
PSNS
based
on
the
Option
2
technology
and
assessed
the
financial
burden
to
new
General
Metals
indirect
dischargers.
Specifically,
EPA's
 
barrier­
to­
entry'
analysis
identified
whether
General
Metals
PSNS
based
on
the
Option
2
technology
would
pose
sufficient
financial
burden
on
new
General
Metals
facilities
to
constitute
a
material
barrier
to
entry
into
the
MP&
M
Point
Source
Category.

9­
13
9.0
­
Technology
Options
EPA
projects
a
barrier
to
entry
for
General
Metals
PSNS
based
on
the
Option
2
technology
because
14
percent
of
General
Metals
indirect
dischargers
have
after­
tax
compliance
costs
between
1
to
3
percent
of
revenue
and
20
percent
have
after­
tax
compliance
costs
between
3
to
5
percent
of
revenue.
Consequently,
EPA
rejected
Option
2
technology
as
the
basis
for
PSNS
in
the
General
Metals
Subcategory.
EPA
has
selected
 
no
further
regulation, 
and
is
not
revising
PSNS
for
new
General
Metals
indirect
dischargers.
Wastewater
discharges
to
POTWs
from
facilities
in
this
subcategory
will
remain
regulated
by
local
limits,
General
Pretreatment
Standards
(
Part
403),
and
Part
433,
as
applicable.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

Metal
Finishing
Job
Shops
Subcategory
EPA
is
not
revising
any
limitations
or
standards
for
facilities
that
would
have
been
subject
to
this
subcategory.
Such
facilities
will
continue
to
be
regulated
by
the
General
Pretreatment
Standards
(
Part
403),
local
limits,
permit
limits,
and
Parts
413
and/
or
433,
as
applicable.

9.3.1
BPT,
BCT,
and
BAT
EPA
evaluated
several
technology
options
for
direct
dischargers
for
the
Metal
Finishing
Job
Shops
(
MFJS)
Subcategory.
Facilities
in
this
subcategory
perform
unit
operations
that
primarily
generate
metal­
bearing
wastewater,
but
may
also
generate
some
oily
wastewater.
EPA
evaluated
Options
1,
2,
2S,
3,
and
4,
which
are
described
in
detail
in
Section
9.2.1.
As
discussed
in
Section
9.2.1,
EPA
dropped
Options
1,
2S,
3,
and
4
from
further
consideration.
Therefore,
for
the
final
rule,
EPA
considered
only
Option
2
as
the
basis
for
limitations
for
the
MFJS
Subcategory.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
2.

EPA
proposed
to
establish
BPT/
BCT/
BAT
for
existing
direct
dischargers
in
the
MFJS
Subcategory
based
on
the
Option
2
technology
(
see
Section
9.2.1
for
a
description
of
Option
2).
EPA
evaluated
the
cost
of
effluent
reductions,
pollutant
reductions,
and
the
economic
achievability
of
compliance
with
BPT/
BCT/
BAT
limitations
based
on
the
Option
2
technology.
Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
in
Sections
11.0
and
12.0,
EPA
determined
that
the
compliance
costs
of
the
Option
2
technology
are
not
economically
achievable.

EPA
estimates
that
compliance
with
BPT/
BCT/
BAT
limitations
based
on
the
Option
2
technology
will
result
in
the
closure
of
50
percent
of
the
existing
direct
dischargers
in
this
subcategory
(
12
of
24
existing
MFJS
direct
dischargers).
Consequently,
EPA
concludes
that,
for
existing
direct
dischargers
in
the
MFJS
Subcategory,
Option
2
is
not
the
best
practicable
control
technology,
best
conventional
pollutant
control
technology,
or
best
available
technology
economically
achievable.
EPA
has
decided
not
to
establish
new
BPT,
BCT,
or
BAT
limitations
9­
14
9.3
9.0
­
Technology
Options
for
existing
MFJS
direct
dischargers
based
on
the
Option
2
technology;
these
discharges
will
remain
subject
to
Part
433.

9.3.2
NSPS
EPA
proposed
to
establish
NSPS
for
new
direct
dischargers
in
the
MFJS
Subcategory
based
on
the
Option
4
technology.
Option
4
technology
is
similar
to
Option
2
(
including
Option
2
flow
control
and
pollution
prevention)
but
includes
oils
removal
using
ultrafiltration
and
solids
separation
by
a
microfilter
(
instead
of
a
clarifier).
As
explained
in
Section
9.2.4,
EPA
concluded
that
its
database
is
insufficient
to
support
a
determination
that
the
Option
4
standards
are
technically
achievable.
Consequently,
EPA
rejected
Option
4
technology
as
the
basis
for
NSPS
in
the
MFJS
Subcategory.

For
the
final
rule,
EPA
evaluated
setting
MFJS
NSPS
based
on
the
Option
2
technology
and
assessed
the
financial
burden
to
new
MFJS
direct
dischargers.
Specifically,
EPA s
 
barrier­
to­
entry 
analysis
identified
whether
MFJS
NSPS
based
on
the
Option
2
technology
would
pose
sufficient
financial
burden
so
as
to
constitute
a
material
barrier
to
entry
into
the
MP&
M
point
source
category.
Additionally,
EPA
reviewed
its
database
for
establishing
MFJS
NSPS
based
on
the
Option
2
technology
as
commentors
indicated
the
proposed
standards
were
not
technically
achievable.

In
response
to
these
comments,
EPA
reviewed
all
the
information
currently
available
on
MFJS
facilities
using
the
Option
2
technology
basis.
This
review
demonstrated
that
process
wastewaters
at
MFJS
facilities
contain
a
wide
variety
of
metals
in
significant
concentrations.
Commentors
stated
that
single­
stage
precipitation
and
solids
separation
may
not
achieve
sufficient
removals
for
wastewaters
that
contain
significant
concentrations
of
a
wide
variety
of
metals,
especially
if
the
metals
preferentially
precipitate
at
disparate
pH
ranges.
Consequently,
to
address
concerns
raised
by
commentors,
EPA
also
costed
new
sources
to
operate
two
separate
chemical
precipitation
and
solids
separation
steps
in
series.
Two­
stage
chemical
precipitation
and
solids
separation
allows
MFJS
facilities
with
multiple
metals
to
control
metal
discharges
to
concentrations
lower
than
single­
stage
chemical
precipitation
and
solids
separation
over
a
wider
pH
range.

Applying
this
revised
costing
approach,
EPA
projects
a
barrier
to
entry
for
MFJS
NSPS
based
on
the
Option
2
technology
because
all
MFJS
direct
dischargers
have
new
source
compliance
costs
that
are
greater
than
5
percent
of
revenue.
Consequently,
EPA
rejected
Option
2
technology
as
the
basis
for
NSPS
in
the
MFJS
Subcategory,
and
is
not
revising
NSPS
for
new
MFJS
direct
dischargers.
Wastewater
discharges
from
these
facilities
in
this
subcategory
will
remain
regulated
by
local
limits
and
Part
433
NSPS
as
applicable.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

9­
15
9.0
­
Technology
Options
9.3.3
PSES
EPA
evaluated
several
technology
options
for
indirect
dischargers
for
the
MFJS
Subcategory,
whose
unit
operations
primarily
generate
metal­
bearing
wastewater,
but
may
also
generate
some
oily
wastewater.
These
include
the
same
option
as
evaluated
for
BAT
(
i.
e.,
Option
2),
as
well
as
several
alternative
options
discussed
below.
EPA
did
not
further
evaluate
Options
1,
2S,
3,
and
4
for
the
final
rule
for
the
same
reasons
as
explained
for
BPT
above.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
2
and
the
alternative
options
considered
for
the
final
rule.

EPA
proposed
to
establish
PSES
for
existing
indirect
dischargers
in
the
MFJS
Subcategory
based
on
the
Option
2
technology.
Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
EPA
determined
that
the
costs
of
Option
2
are
not
economically
achievable
for
existing
indirect
dischargers
in
the
MFJS
Subcategory.
EPA
estimates
that
compliance
with
PSES
based
on
the
Option
2
technology
will
result
in
the
closure
of
46
percent
of
the
existing
indirect
dischargers
in
this
subcategory
(
589
of
1,270
existing
MFJS
indirect
dischargers),
which
EPA
considers
to
be
too
high.
EPA
has
determined
that
Option
2
technology
is
not
the
best
available
technology
economically
achievable
for
existing
indirect
dischargers
in
the
MFJS
Subcategory.
Therefore,
EPA
is
not
establishing
PSES
for
this
subcategory
based
on
the
Option
2
technology.

As
discussed
in
the
January
2001
proposal
(
66
FR
551)
and
June
2002
NODA
(
67
FR
38801),
EPA
also
considered
a
number
of
alternative
options
whose
economic
impacts
would
be
less
costly
than
Option
2
technology.
These
options
potentially
have
compliance
costs
more
closely
aligned
with
toxic
pollutant
reductions.
EPA
considered
the
following
alternative
options
for
the
final
rule:

 
Option
A:
No
change
in
current
regulation;

 
Option
B:
Option
2
with
a
higher
low­
flow
exclusion;

 
Option
C:
Upgrading
facilities
currently
covered
by
Part
413
to
meet
the
PSES
of
Part
433
( 
413
to
433
Upgrade
Option 
described
in
Section
9.2.5);
and
 
Option
D:
Pollution
prevention
option
(
see
66
FR
551).

All
facilities
in
the
MFJS
Subcategory
are
currently
subject
to
Part
413,
Part
433
or
both.

As
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
based
on
comments,
EPA
has
revised
its
methodology
for
estimating
compliance
costs
and
pollutant
loadings
for
Option
2,
low­
flow
exclusions
(
Option
B),
and
the
 
upgrade 
option
(
Option
C)
previously
described.
Using
information
from
this
revised
analysis,
EPA
concludes
9­
16
9.0
­
Technology
Options
that
neither
of
these
alternative
options
(
Options
B
or
C)
are
economically
achievable.
EPA
rejected
Options
B
and
C
because
more
than
10
percent
of
existing
indirect
dischargers
not
covered
by
Part
433
close
at
the
upgrade
option.

EPA
also
solicited
comment
in
the
January
2001
proposal
on
a
pollution
prevention
alternative
for
indirect
dischargers
in
this
subcategory
(
Option
D).
Commentors
supported
Option
D
and
stated
that
the
pollution
prevention
practices
identified
by
EPA
in
the
January
2001
proposal
represent
environmentally
sound
practices
for
the
metal
finishing
industry.
The
commentors
also
stated
that
Option
D
should,
however,
be
implemented
on
a
voluntary
basis
similar
to
the
National
Metal
Finishing
Strategic
Goals
Program
(
see
66
FR
511).
Control
authorities
also
commented
that
Option
D
may
increase
their
administrative
burden
because
of
additional
review
of
facility
operations
and
compliance
with
the
approved
pollution
prevention
plan,
and
enforcement
of
Option
D
may
be
more
difficult
than
other
options
considered.
EPA
is
not
promulgating
Option
D
for
facilities
in
the
MFJS
Subcategory
for
the
final
rule
due
to
the
increased
administrative
burden
on
pretreatment
control
authorities
and
potential
problems
enforcing
Option
D.
Section
8.0
describes
many
of
the
pollution
prevention
practices
that
were
considered
for
Option
D.
These
pollution
prevention
practices
may
be
useful
in
helping
facilities
lower
operating
costs,
improve
environmental
performance,
and
foster
other
important
benefits.

EPA
is
not
establishing
PSES
for
existing
indirect
dischargers
in
the
MFJS
Subcategory.
Wastewater
discharges
to
POTWs
from
facilities
in
this
subcategory
will
remain
regulated
by
General
Pretreatment
Standards
(
Part
403),
and
Parts
413
and/
or
433,
as
applicable.
EPA
also
notes
that
facilities
regulated
by
Parts
413
and/
or
433
PSES
must
comply
with
Part
433
PSNS
if
the
changes
to
their
facilities
are
determined
to
make
them
new
sources.

9.3.4
PSNS
EPA
proposed
to
establish
PSNS
for
indirect
dischargers
in
the
MFJS
Subcategory
based
on
the
Option
4
technology.
Option
4
technology
is
similar
to
Option
2
(
including
Option
2
flow
control
and
pollution
prevention)
but
includes
oils
removal
using
ultrafiltration
and
solids
separation
by
a
microfilter
(
instead
of
a
clarifier).
As
explained
in
Section
9.2.4,
EPA
concluded
its
database
is
insufficient
to
support
a
determination
that
the
Option
4
standards
are
technically
achievable.
Consequently,
EPA
rejected
Option
4
technology
as
the
basis
for
PSNS
in
the
MFJS
Subcategory.

For
the
final
rule,
EPA
evaluated
setting
MFJS
PSNS
based
on
the
Option
2
technology
and
assessed
the
financial
burden
to
new
MFJS
indirect
dischargers.
Specifically,
EPA's
 
barrier­
to­
entry'
analysis
identified
whether
MFJS
PSNS
based
on
the
Option
2
technology
would
pose
sufficient
financial
burden
on
new
MFJS
facilities
to
constitute
a
material
barrier
to
entry
into
the
MP&
M
Point
Source
Category.

EPA
projects
a
barrier
to
entry
for
MFJS
PSNS
based
on
the
Option
2
technology
because
8
percent
of
MFJS
indirect
dischargers
have
after­
tax
compliance
costs
between
1
to
3
9­
17
9.0
­
Technology
Options
percent
of
revenue,
5
percent
have
after­
tax
compliance
costs
between
3
to
5
percent
of
revenue,
and
6
percent
have
after­
tax
compliance
costs
greater
than
5
percent
of
revenue.
Consequently,
EPA
rejected
Option
2
technology
as
the
basis
for
PSNS
in
the
MFJS
Subcategory,
and
is
not
revising
PSNS
for
new
MFJS
indirect
dischargers.
Wastewater
discharges
to
POTWs
from
facilities
in
this
subcategory
will
remain
regulated
by
local
limits,
General
Pretreatment
Standards
(
Part
403),
and
Part
433,
as
applicable.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

Non­
Chromium
Anodizing
Subcategory
EPA
is
not
revising
limitations
or
standards
for
any
facilities
that
would
have
been
subject
to
this
subcategory.
Such
facilities
will
continue
to
be
regulated
by
the
General
Pretreatment
Standards
(
Part
403),
local
limits,
permit
limits,
and
Parts
413
and/
or
433,
as
applicable.

9.4.1
BPT,
BCT,
and
BAT
As
previously
discussed,
after
publication
of
the
June
2002
NODA,
EPA
conducted
another
review
of
all
Non­
Chromium
Anodizing
(
NCA)
facilities
in
the
MP&
M
survey
database
to
determine
the
destination
of
discharged
wastewater
(
i.
e.,
either
directly
to
surface
waters
or
indirectly
to
POTWs
or
both)
and
the
applicability
of
the
final
rule
to
discharged
wastewaters.
As
a
result
of
this
review,
EPA
did
not
identify
any
NCA
direct
discharging
facilities
or
NCA
facilities
that
do
not
discharge
wastewater
(
i.
e.,
zero
discharge
or
contract
haulers)
or
do
not
use
process
water
(
dry
facilities)
in
its
rulemaking
record.
All
of
the
NCA
facilities
in
EPA s
database
are
indirect
dischargers.
Therefore,
EPA
cannot
evaluate
treatment
systems
at
direct
dischargers.
As
a
result,
EPA
transferred
cost
and
pollutant
loading
data
from
the
best
performing
indirect
facilities
in
order
to
evaluate
direct
discharging
limitations
in
this
subcategory.

EPA
evaluated
several
technology
options
for
direct
dischargers
for
the
NCA
Subcategory,
whose
unit
operations
primarily
generate
metal­
bearing
wastewater,
but
may
also
generate
some
oily
wastewater.
These
include
Options
1,
2,
2S,
3,
and
4,
which
are
described
in
detail
in
Section
9.2.1.
As
discussed
in
Section
9.2.1,
EPA
dropped
Options
1,
2S,
3,
and
4
from
further
consideration.
Therefore,
for
the
final
rule,
EPA
considered
only
Option
2
as
the
basis
for
limitations
for
the
NCA
Subcategory.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
2.

In
2001,
EPA
proposed
to
establish
BPT/
BCT/
BAT
limitations
for
direct
dischargers
in
the
NCA
Subcategory
based
on
the
Option
2
technology.
EPA
evaluated
the
cost
of
effluent
reductions,
quantity
of
pollutant
reductions,
and
the
economic
achievability
of
compliance
with
BPT/
BCT/
BAT
limitations
based
on
the
Option
2
technology.
Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
the
costs
of
the
Option
2
technology
were
9­
18
9.4
9.0
­
Technology
Options
disproportionate
to
the
projected
toxic
pollutants
reductions
(
cost­
effectiveness
values
(
in
1981$)
in
excess
of
$
1,925/
PE).

EPA
decided
not
to
establish
BPT/
BAT
limitations
based
on
the
Option
2
technology
for
the
NCA
Subcategory
for
following
reasons:
(
1)
EPA
identified
no
NCA
direct
dischargers,
and
(
2)
the
costs
of
Option
2
are
disproportionate
to
the
estimated
toxic
pollutant
reductions
(
i.
e.,
$
1,925/
PE).
EPA
concludes
that
for
existing
direct
dischargers
in
the
NCA
Subcategory,
Option
2
is
not
the
best
practicable
control
technology,
best
conventional
pollutant
control
technology,
or
best
available
technology
economically
achievable.
EPA
has
decided
not
to
establish
new
BPT,
BCT,
or
BAT
limitations
for
existing
NCA
direct
dischargers
based
on
the
Option
2
technology.
Although,
EPA
identified
no
NCA
direct
dischargers
through
its
survey
efforts,
if
such
facilities
do
exist,
they
would
be
subject
to
Part
433.

9.4.2
NSPS
EPA
proposed
to
establish
NSPS
for
direct
dischargers
in
the
NCA
Subcategory
based
on
the
Option
2
technology.
For
the
final
rule,
EPA
evaluated
setting
NCA
NSPS
based
on
the
Option
2
technology
and
assessed
the
financial
burden
to
new
NCA
direct
dischargers.
Specifically,
EPA's
 
barrier­
to­
entry'
analysis
identified
whether
NCA
NSPS
based
on
the
Option
2
technology
would
pose
sufficient
financial
burden
on
new
NCA
facilities
to
constitute
a
material
barrier
to
entry
into
the
MP&
M
Point
Source
Category.

EPA
projects
a
barrier
to
entry
for
NCA
NSPS
based
on
the
Option
2
technology
because
approximately
26
percent
of
NCA
direct
dischargers
have
new
source
compliance
costs
that
are
between
3
percent
and
5
percent
of
revenue.
Consequently,
EPA
rejected
Option
2
technology
as
the
basis
for
NSPS
in
the
NCA
Subcategory.
EPA
has
selected
 
no
further
regulation 
for
new
NCA
direct
dischargers
and
is
not
revising
NSPS
for
new
NCA
direct
dischargers,
which
will
remain
subject
to
Part
433.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

9.4.3
PSES
and
PSNS
EPA
proposed
 
no
further
regulation 
for
existing
and
new
indirect
dischargers
in
the
NCA
Subcategory.
EPA
based
this
decision
on
the
economic
impacts
to
indirect
dischargers
associated
with
Option
2
and
the
small
quantity
of
toxic
pollutants
discharged
by
facilities
in
this
subcategory,
even
after
a
economically
achievable
flow
cutoff
is
applied
(
see
66
FR
467).
For
the
reasons
set
out
in
the
2001
proposal,
EPA
has
decided
not
to
establish
new
regulations
and
is
not
establishing
PSES
or
PSNS
in
the
NCA
Subcategory.
These
facilities
remain
subject
to
Parts
413
or
433,
or
both,
as
applicable.
EPA
also
notes
that
facilities
regulated
by
Parts
413
and/
or
433
PSES
must
comply
with
Part
433
PSNS
if
the
changes
to
their
facilities
are
determined
to
make
them
new
sources.

9­
19
9.0
­
Technology
Options
9.5
Printed
Wiring
Board
Subcategory
EPA
is
not
revising
any
limitations
or
standards
for
facilities
that
would
have
been
subject
to
this
subcategory.
Such
facilities
will
continue
to
be
regulated
by
the
General
Pretreatment
Standards
(
Part
403),
local
limits,
permit
limits,
and
Parts
413
and/
or
433,
as
applicable.

9.5.1
BPT,
BCT,
and
BAT
EPA
evaluated
several
technology
options
for
direct
dischargers
for
the
Printed
Wiring
Board
(
PWB)
Subcategory,
whose
unit
operations
primarily
generate
metal­
bearing
wastewater,
but
may
also
generate
some
oily
wastewater.
These
include
Options
1,
2,
2S,
3,
and
4,
which
are
described
in
detail
in
Section
9.2.1.
As
discussed
in
Section
9.2.1,
EPA
dropped
Options
1,
2S,
3,
and
4
from
further
consideration.
Therefore,
for
the
final
rule,
EPA
considered
only
Option
2
as
the
basis
for
limitations
for
the
PWB
Subcategory.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
2.

EPA
proposed
to
establish
BPT/
BCT/
BAT
for
direct
dischargers
in
the
PWB
Subcategory
based
on
the
Option
2
technology
(
see
Section
9.2.1
for
a
description
of
Option
2).
EPA
evaluated
the
cost
of
effluent
reductions,
pollutant
reductions,
and
the
economic
achievability
of
compliance
with
BPT/
BCT/
BAT
limitations
based
on
the
Option
2
technology.

Based
on
MP&
M
survey
information,
EPA
estimates
that
compliance
with
BPT/
BCT/
BAT
limitations
based
on
the
Option
2
technology
results
in
no
closures
of
the
existing
eight
direct
dischargers
in
the
PWB
Subcategory.
However,
EPA
decided
not
to
establish
BPT/
BAT
limitations
based
on
the
Option
2
technology
for
the
PWB
Subcategory
for
the
following
reasons:
(
1)
EPA
identified
only
eight
existing
PWB
direct
dischargers
and
all
of
these
PWB
direct
dischargers
are
currently
regulated
by
existing
effluent
guidelines
(
Part
433),
and
(
2)
the
costs
of
Option
2
are
disproportionate
to
the
estimated
toxic
pollutant
reductions.
EPA
estimates
compliance
costs
of
$
0.3
million
(
2001$
dollars)
with
only
186
toxic
pound­
equivalents
(
PE)
being
removed.
This
equates
to
a
cost­
effectiveness
value
(
in
1981$)
of
approximately
$
900/
PE.
EPA
concludes
that,
for
existing
direct
dischargers
in
the
PWB
Subcategory,
Option
2
is
not
the
best
practicable
control
technology,
best
conventional
pollutant
control
technology,
or
best
available
technology
economically
achievable.
EPA
has
decided
not
to
establish
new
BPT,
BCT,
or
BAT
limitations
for
existing
PWB
direct
dischargers
based
on
the
Option
2
technology;
these
discharges
will
remain
subject
to
Part
433.

9.5.2
NSPS
EPA
proposed
to
establish
NSPS
for
new
direct
dischargers
in
the
PWB
Subcategory
based
on
the
Option
4
technology.
Option
4
technology
is
similar
to
Option
2
(
including
Option
2
flow
control
and
pollution
prevention)
but
includes
oils
removal
using
ultrafiltration
and
solids
separation
by
a
microfilter
(
instead
of
a
clarifier).
As
explained
in
Section
9.2.4,
EPA
concluded
that
its
database
is
insufficient
to
support
a
determination
that
the
9­
20
9.0
­
Technology
Options
Option
4
standards
are
technically
achievable.
Consequently,
EPA
rejected
Option
4
technology
as
the
basis
for
NSPS
in
the
PWB
Subcategory.

For
the
final
rule,
EPA
evaluated
setting
PWB
NSPS
based
on
the
Option
2
technology.
EPA
reviewed
its
database
for
establishing
PWB
NSPS
based
on
the
Option
2
technology
as
commentors
indicated
the
proposed
standards
were
not
technically
achievable.
In
response
to
these
comments,
EPA
reviewed
all
the
information
currently
available
on
PWB
facilities
using
the
Option
2
technology
basis.
EPA
now
concludes
that
the
PWB s
Option
2
database
can
only
be
used
to
establish
limitations
for
copper,
nickel,
and
tin.
In
order
to
assess
the
difference
between
current
NSPS
requirements
(
from
Part
433)
for
PWB
facilities
and
those
under
consideration
in
the
final
rule,
EPA
estimated
the
incremental
quantities
of
copper,
nickel,
and
tin
that
would
be
reduced
if
a
new
PWB
facility
were
required
to
meet
NSPS
based
on
the
Option
2
technology
rather
than
NSPS
based
on
Part
433.
EPA
analysis
shows
minimal
amounts
of
pollutant
reductions
based
on
more
stringent
requirements
on
copper,
nickel,
and
tin.

Consequently,
EPA
rejected
Option
2
technology
as
the
basis
for
NSPS
in
the
PWB
Subcategory
based
on
the
small
incremental
quantity
of
toxic
pollutants
that
would
be
reduced
in
relation
to
existing
requirements.
EPA
is
not
establishing
NSPS
or
revising
existing
NSPS
for
new
PWB
direct
dischargers.
Wastewater
discharges
from
these
facilities
in
this
subcategory
will
remain
regulated
by
permit
limits
and
Part
433
as
applicable.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

9.5.3
PSES
EPA
evaluated
several
technology
options
for
indirect
dischargers
for
the
PWB
Subcategory,
whose
unit
operations
primarily
generate
metal­
bearing
wastewater,
but
may
also
generate
some
oily
wastewater.
These
include
the
same
option
as
evaluated
for
BAT
(
i.
e.,
Option
2
as
described
in
Section
9.2.1),
as
well
as
several
alternative
options
described
below.
EPA
did
not
further
evaluate
Options
1,
2S,
3,
and
4
for
the
final
rule
for
the
same
reasons
as
explained
for
BPT
above.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
2
and
the
alternative
options
considered
for
the
final
rule.

EPA
proposed
to
establish
PSES
for
existing
indirect
dischargers
in
the
PWB
Subcategory
based
on
the
Option
2
technology.
Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
EPA
rejected
promulgating
PSES
for
existing
indirect
dischargers
in
the
PWB
Subcategory
based
on
the
Option
2
technology
for
the
following
reasons:
(
1)
all
PWB
indirect
dischargers
are
currently
regulated
by
existing
effluent
guidelines
(
Parts
413
or
433
or
both,
as
applicable);
(
2)
EPA
estimates
that
compliance
with
PSES
based
on
the
Option
2
technology
will
result
in
the
closure
of
6.5
percent
of
the
existing
indirect
dischargers
in
this
subcategory
(
55
of
840
existing
PWB
indirect
dischargers);
and
(
3)
EPA
determined
that
the
toxic
pollutant
reductions
are
very
expensive
per
pound
removed
(
the
cost­
effectiveness
value
(
in
1981$)
is
9­
21
9.0
­
Technology
Options
$
455/
PE).
EPA
has
determined
that
Option
2
technology
is
not
the
best
available
technology
economically
achievable
for
existing
indirect
dischargers
in
the
PWB
Subcategory,
and
therefore
is
not
establishing
PWB
PSES
based
on
the
Option
2
technology.

As
discussed
in
the
June
2002
NODA
(
see
67
FR
38802),
EPA
also
considered
a
number
of
alternative
options
whose
economic
impacts
would
be
less
costly
than
Option
2
technology.
These
options
potentially
have
compliance
costs
more
closely
aligned
with
toxic
pollutant
reductions.
EPA
considered
the
following
alternative
options
for
the
final
rule:

 
Option
A:
No
change
in
current
regulation;

 
Option
B:
Option
2
with
a
higher
low­
flow
exclusion;
and
 
Option
C:
Upgrading
facilities
currently
covered
by
Part
413
to
the
PSES
of
Part
433
( 
413
to
433
Upgrade
Option ).

EPA
notes
that
all
facilities
in
the
PWB
Subcategory
are
currently
subject
to
Part
413,
Part
433,
or
both.

As
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
based
on
comments,
EPA
has
revised
its
methodology
for
estimating
compliance
costs
and
pollutant
loadings
for
Option
2,
higher
low­
flow
exclusions
(
Option
B),
and
the
 
upgrade 
option
(
Options
C)
previously
described.
Using
information
from
this
revised
analysis,
EPA
rejected
Options
B
and
C
because:
(
1)
more
than
10
percent
of
existing
indirect
dischargers
not
covered
by
Part
433
close
at
the
upgrade
option;
or
(
2)
the
incremental
compliance
costs
of
the
upgrade
options
were
too
great
in
terms
of
toxic
removals
(
cost­
effectiveness
values
(
in
1981$)
in
excess
of
$
833/
PE).
Therefore,
EPA
is
not
revising
PSES
for
existing
indirect
dischargers
in
the
PWB
Subcategory.
Wastewater
discharges
to
POTWs
from
facilities
in
this
subcategory
will
remain
regulated
by
General
Pretreatment
Standards
(
Part
403)
and
Parts
413
and/
or
433,
as
applicable.
EPA
also
notes
that
facilities
regulated
by
Parts
413
and/
or
433
PSES
must
comply
with
Part
433
PSNS
if
the
changes
to
their
facilities
are
determined
to
make
them
new
sources.

9.5.4
PSNS
EPA
proposed
to
establish
PSNS
for
indirect
dischargers
in
the
PWB
Subcategory
based
on
the
Option
4
technology.
Option
4
technology
is
similar
to
Option
2
(
including
Option
2
flow
control
and
pollution
prevention)
but
includes
oils
removal
using
ultrafiltration
and
solids
separation
by
a
microfilter
(
instead
of
a
clarifier).
As
explained
in
Section
9.2.4,
EPA
concluded
that
its
database
is
insufficient
to
support
a
determination
that
the
Option
4
standards
are
technically
achievable.
Consequently,
EPA
rejected
Option
4
technology
as
the
basis
for
PSNS
in
the
PWB
Subcategory.

For
the
final
rule,
EPA
evaluated
setting
PWB
PSNS
based
on
the
Option
2
technology
and
assessed
the
financial
burden
to
new
PWB
indirect
dischargers.
Specifically,

9­
22
9.0
­
Technology
Options
EPA's
 
barrier­
to­
entry'
analysis
identified
whether
PWB
PSNS
based
on
the
Option
2
technology
would
pose
sufficient
financial
burden
on
new
PWB
facilities
to
constitute
a
material
barrier
to
entry
into
the
MP&
M
Point
Source
Category.

EPA
projects
a
barrier
to
entry
for
PWB
PSNS
based
on
the
Option
2
technology
because
3
percent
of
PWB
indirect
dischargers
have
after­
tax
compliance
costs
between
1
to
3
percent
of
revenue
and
4
percent
have
after­
tax
compliance
costs
greater
than
5
percent
of
revenue.
Consequently,
EPA
rejected
Option
2
technology
as
the
basis
for
PSNS
in
the
PWB
Subcategory.
EPA
has
selected
 
no
further
regulation 
for
new
PWB
indirect
dischargers
and
is
not
revising
PSNS
for
new
PWB
indirect
dischargers.
Wastewater
discharges
to
POTWs
from
facilities
in
this
subcategory
will
remain
regulated
by
local
limits,
General
Pretreatment
Standards
(
Part
403),
and
Part
433,
as
applicable.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

Steel
Forming
and
Finishing
Subcategory
EPA
is
not
revising
limitations
or
standards
for
any
facilities
that
would
have
been
subject
to
this
subcategory.
Such
facilities
will
continue
to
be
regulated
by
the
General
Pretreatment
Standards
(
Part
403),
local
limits,
permit
limits,
and
Iron
and
Steel
effluent
limitations
guidelines
(
Part
420),
as
applicable.

9.6.1
BPT,
BCT,
and
BAT
EPA
evaluated
several
technology
options
for
direct
dischargers
for
the
Steel
Forming
and
Finishing
(
SFF)
Subcategory,
whose
unit
operations
primarily
generate
metal­
bearing
wastewater,
but
may
also
generate
some
oily
wastewater.
These
include
Options
1,
2,
2S,
3,
and
4,
which
are
described
in
detail
in
Section
9.2.1.
As
discussed
Section
9.2.1,
EPA
dropped
Options
1,
2S,
3,
and
4
from
further
consideration.
Therefore,
for
the
final
rule,
EPA
considered
only
Option
2
as
the
basis
for
limitations
for
the
SFF
Subcategory.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
2.

EPA
proposed
to
establish
BPT/
BCT/
BAT
for
existing
direct
dischargers
in
the
SFF
Subcategory
based
on
the
Option
2
technology
(
see
Section
9.2.1
for
a
description
of
Option
2).
For
the
final
rule,
EPA
evaluated
the
cost
of
effluent
reductions,
pollutant
reductions,
and
the
economic
achievability
of
compliance
with
BPT/
BCT/
BAT
limitations
based
on
the
Option
2
technology.
Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
EPA
determined
that
the
compliance
costs
of
Option
2
are
not
economically
achievable.
EPA
estimates
that
compliance
with
BPT/
BCT/
BAT
limitations
based
on
the
Option
2
technology
will
result
in
the
closure
of
17
percent
of
the
existing
direct
dischargers
in
this
subcategory
(
7
of
41
existing
SFF
direct
dischargers).
EPA
concludes
that,
for
existing
direct
dischargers
in
the
SFF
Subcategory,
Option
2
is
not
the
best
practicable
control
technology,
best
conventional
pollutant
control
technology,
or
best
available
technology
economically
achievable,
and
therefore,
EPA
is
not
9­
23
9.6
9.0
­
Technology
Options
establishing
new
BPT,
BCT,
or
BAT
limitations
for
existing
SFF
direct
dischargers
based
on
the
Option
2
technology.
These
facilities
will
remain
subject
to
Part
420.

9.6.2
NSPS
EPA
proposed
to
establish
NSPS
for
new
direct
dischargers
in
the
SFF
Subcategory
based
on
the
Option
4
technology.
Option
4
technology
is
similar
to
Option
2
(
including
Option
2
flow
control
and
pollution
prevention)
but
includes
oils
removal
using
ultrafiltration
and
solids
separation
by
a
microfilter
(
instead
of
a
clarifier).
As
explained
in
Section
9.2.4,
EPA
concluded
that
its
database
is
insufficient
to
support
a
determination
that
the
Option
4
standards
are
technically
achievable.
Consequently,
EPA
rejected
Option
4
technology
as
the
basis
for
NSPS
in
the
SFF
Subcategory.
EPA
has
selected
 
no
further
regulation 
for
new
SFF
direct
dischargers
and
is
not
revising
NSPS
for
new
SFF
direct
dischargers,
which
will
remain
subject
to
Part
420.

9.6.3
PSES
EPA
evaluated
several
technology
options
for
indirect
dischargers
for
the
Steel
Forming
and
Finishing
Subcategory,
whose
unit
operations
primarily
generate
metal­
bearing
wastewater,
but
may
also
generate
some
oily
wastewater.
For
the
final
rule,
EPA
considered
the
same
option
as
evaluated
for
BAT
(
i.
e.,
Option
2).
EPA
did
not
further
evaluate
Options
1,
2S,
3,
and
4
for
the
final
rule
for
the
same
reasons
as
explained
for
BPT
above.
See
the
Development
Document
for
the
Proposed
Effluent
Limitations
Guidelines
and
Standards
for
the
Metal
Products
&
Machinery
Point
Source
Category
(
EPA
821­
B­
00­
005)
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
2.

EPA
proposed
to
establish
PSES
for
existing
indirect
dischargers
in
the
SFF
Subcategory
based
on
the
Option
2
technology.
Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
EPA
estimates
that
compliance
with
PSES
based
on
the
Option
2
technology
will
result
in
the
closure
of
9
percent
of
the
existing
indirect
dischargers
in
this
subcategory
(
10
of
112
existing
SFF
indirect
dischargers).

EPA
has
determined
that
Option
2
technology
is
not
the
best
available
technology
economically
achievable
for
existing
indirect
dischargers
in
the
SFF
Subcategory,
and
therefore
EPA
is
not
revising
PSES
for
this
subcategory
based
on
the
Option
2
technology.
Wastewater
discharges
to
POTWs
from
these
facilities
will
remain
regulated
by
General
Pretreatment
Standards
(
Part
403)
and
Part
420.

9.6.4
PSNS
EPA
proposed
to
establish
PSNS
for
indirect
dischargers
in
the
SFF
Subcategory
based
on
the
Option
4
technology.
Option
4
technology
is
similar
to
Option
2
(
including
Option
2
flow
control
and
pollution
prevention)
but
includes
oils
removal
using
ultrafiltration
and
solids
9­
24
9.0
­
Technology
Options
separation
by
a
microfilter
(
instead
of
a
clarifier).
As
explained
in
Section
9.2.4,
EPA
concluded
its
database
is
insufficient
to
support
a
determination
that
the
Option
4
standards
are
technically
achievable.
Consequently,
EPA
rejected
Option
4
technology
as
the
basis
for
PSNS
in
the
SFF
Subcategory.
EPA
has
selected
 
no
further
regulation 
for
new
SFF
indirect
dischargers
and
is
not
revising
PSNS
for
new
SFF
indirect
dischargers;
these
facilities
will
remain
subject
to
Part
420.

Oily
Wastes
Subcategory
EPA
is
promulgating
limitations
and
standards
for
existing
and
new
direct
dischargers
in
the
Oily
Wastes
Subcategory
based
on
the
proposed
Option
6
technology
(
see
Section
9.7.1).
EPA
is
not
promulgating
pretreatment
standards
for
existing
or
new
indirect
dischargers
in
this
subcategory.

9.7.1
BPT
EPA
evaluated
several
technology
options
for
the
direct
dischargers
in
the
Oily
Wastes
Subcategory.
Each
of
these
options
is
discussed
below.
As
discussed
in
Section
6.0,
EPA
defines
the
Oily
Wastes
Subcategory
as
those
facilities
that
only
discharge
wastewater
from
one
or
more
oily
operations
(
see
Table
6­
2
and
40
CFR
438.2(
f)).

Option
5
Option
5
consists
of
end­
of­
pipe
chemical
emulsion
breaking
followed
by
gravity
separation
using
an
oil/
water
separator.
EPA
performed
sampling
episodes
at
several
facilities
in
the
Oily
Wastes
Subcategory
that
used
chemical
emulsion
breaking
followed
by
gravity
flotation
and
oil
skimming.
These
systems
typically
achieved
a
96­
percent
removal
of
oil
and
grease.
Breaking
the
oil/
water
emulsion
requires
adding
treatment
chemicals
such
as
acid,
alum,
and/
or
polymers
to
change
the
emulsified
oils
or
cutting
fluids
from
hydrophilic
colloids
to
aggregate
hydrophobic
particles.
The
aggregated
oil
particles,
with
a
density
less
than
water,
can
be
removed
by
gravity
flotation
in
a
coalescing
plate
oil/
water
separator.
Option
5
also
includes
contract
hauling
of
organic
solvent­
bearing
wastewaters
instead
of
discharge.

Option
6
Option
6
consists
of
the
technologies
in
Option
5
plus
the
following
in­
process
flow
control
and
pollution
prevention
technologies,
which
allow
for
recovery
and
reuse
of
materials
along
with
water
conservation:

 
Two­
stage
countercurrent
cascade
rinsing
for
all
flowing
rinses;

 
Centrifugation
and
recycling
of
painting
water
curtains;
and
9­
25
9.7
9.0
­
Technology
Options
 
Centrifugation,
pasteurization,
and
recycling
of
water­
soluble
machining
coolants.

Option
7
Option
7
consists
of
end­
of­
pipe
ultrafiltration,
as
well
as
contract
hauling
of
organic
solvent­
bearing
wastewater
instead
of
discharge.
Sampling
episode
data
determined
that,
on
average,
ultrafilters
will
remove
greater
than
99
percent
of
all
oil
and
grease
in
the
influent
stream.

Option
8
Option
8
consists
of
the
Option
7
technology
(
ultrafiltration)
plus
the
pollution
prevention
and
water
conservation
alternatives
described
in
Option
6.

Option
Selection
As
discussed
in
the
2001
proposal
(
66
FR
451),
EPA
dropped
Options
5
and
7
from
further
consideration
because
Options
6
and
8,
respectively,
cost
less
and
provided
greater
pollutant
removals.
Subsequent
to
proposal,
EPA
also
dropped
Option
8
from
further
consideration
for
the
final
rule
because
of
its
increased
cost
and
lack
of
significant
additional
pollutant
removals
beyond
Option
6.
Therefore,
for
the
final
rule,
EPA
considered
only
Option
6
as
the
basis
for
limitations
for
the
Oily
Wastes
Subcategory.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
6.

EPA
is
establishing
BPT
pH
limitations
and
daily
maximum
limitations
for
two
pollutants,
oil
and
grease
as
hexane
extractable
material
(
oil
and
grease
(
as
HEM))
and
total
suspended
solids
(
TSS),
for
direct
dischargers
in
the
Oily
Wastes
Subcategory
based
on
the
proposed
technology
option
(
Option
6).
Option
6
technology
includes
the
following
treatment
measures:
(
1)
in­
process
flow
control
and
pollution
prevention;
and
(
2)
oil/
water
separation
by
chemical
emulsion
breaking
and
skimming
(
see
above
for
additional
details
on
the
Option
6
technology).

The
Agency
concluded
that
the
Option
6
treatment
technology
represents
the
best
practicable
control
technology
currently
available
and
should
be
the
basis
for
the
BPT
Oily
Wastes
limitations
for
the
following
reasons.
First,
this
technology
is
available
and
readily
applicable
to
all
facilities
in
the
Oily
Wastes
Subcategory.
Approximately
42
percent
of
the
direct
dischargers
in
the
Oily
Wastes
Subcategory
currently
use
the
Option
6
technology.
Second,
the
cost
of
compliance
with
these
limitations
in
relation
to
the
effluent
reduction
benefits
is
not
wholly
disproportionate.
None
of
these
wastewater
discharges
are
currently
subject
to
national
effluent
limitations
guidelines
and
the
final
rule
will
control
wastewater
discharges
from
a
significant
number
(
2,382)
of
facilities.

9­
26
9.0
­
Technology
Options
EPA
estimates
that
compliance
with
BPT
limitations
based
on
Option
6
technology
will
result
in
no
closures
of
the
existing
direct
dischargers
in
the
Oily
Wastes
Subcategory.
Moreover,
the
adoption
of
this
level
of
control
will
significantly
reduce
the
amount
of
pollutants
discharged
into
the
environment
by
facilities
in
this
subcategory.
For
facilities
in
the
Oily
Wastes
Subcategory
at
Option
6,
EPA
estimates
an
annual
compliance
cost
of
$
13.8
million
(
pre­
tax,
2001$)
and
480,325
pounds
of
conventional
pollutants
removed
from
current
discharges
into
the
Nation s
waters
at
a
cost
of
$
28.73/
pound­
pollutant
removed
(
2001$).
EPA
has,
therefore,
determined
that
the
total
cost
of
effluent
reductions
as
a
result
of
using
the
Option
6
technology
are
reasonable
in
relation
to
the
effluent
reduction
benefits.
(
In
estimating
the
pounds
of
pollutant
removed
by
implementing
Option
6
technology
for
direct
dischargers
in
the
Oily
Wastes
Subcategory,
EPA
used
the
sum
of
oil
and
grease
(
as
HEM)
and
TSS
pounds
removed
to
avoid
any
significant
double
counting
of
pollutants).

The
2001
proposal
also
contains
detailed
discussions
explaining
why
EPA
rejected
BPT
limitations
based
on
other
BPT
technology
options
(
see
66
FR
457).
The
information
in
the
record
for
the
final
rule
provides
no
basis
for
EPA
to
change
this
conclusion.

In
the
2001
proposal,
EPA
proposed
to
regulate
sulfide
in
addition
to
pH,
oil
and
grease
(
as
HEM),
and
TSS.
In
the
final
rule,
EPA
has
not
established
a
sulfide
limitation
because
it
may
serve
as
a
treatment
chemical
(
see
Section
7.0).
EPA
also
proposed
three
alternatives
to
control
discharges
of
toxic
organics
in
MP&
M
process
wastewaters:
(
1)
meet
a
numerical
limit
for
the
total
sum
of
a
list
of
specified
organic
pollutants
(
similar
to
the
Total
Toxic
Organic
(
TTO)
parameter
used
in
the
Metal
Finishing
effluent
limitations
guidelines);
(
2)
meet
a
numerical
limit
for
total
organic
carbon
(
TOC)
as
an
indicator
parameter;
or
(
3)
develop
and
certify
the
implementation
of
an
organic
chemicals
management
plan.
EPA
evaluated
the
analytical
wastewater
and
treatment
technology
data
from
Oily
Wastes
facilities
and
concluded
it
should
not
establish
a
separate
indicator
parameter
or
control
mechanism
for
toxic
organics.
Optimizing
the
separation
of
oil
and
grease
from
wastewater
using
the
Option
6
technology
will
similarly
optimize
the
removal
of
toxic
organic
pollutants
amenable
to
this
treatment
technology.
Consequently,
EPA
is
effectively
controlling
toxic
organics
and
other
priority
and
nonconventional
pollutant
discharges
in
Oily
Wastes
Subcategory
process
wastewaters
by
regulating
oil
and
grease
(
as
HEM).

In
its
analyses,
EPA
estimated
that
facilities
will
monitor
once
per
month
for
oil
and
grease
(
as
HEM)
and
TSS.
EPA
expects
that
12
data
points
for
each
pollutant
per
year
will
yield
a
meaningful
basis
for
establishing
compliance
with
the
promulgated
limitations
through
long­
term
trends
and
short­
term
variability
in
oil
and
grease
(
as
HEM)
and
TSS
pollutant
discharge
loading
patterns.

Although
EPA
is
not
changing
the
technology
basis
from
that
proposed,
EPA
is
revising
all
of
the
proposed
Oily
Wastes
Subcategory
BPT
limitations.
This
is
a
result
of
a
recalculation
of
the
limitations
after
EPA
revised
the
data
sets
used
to
calculate
the
promulgated
limitations
to
reflect
changes
including
corrections
and
additional
data
(
see
67
FR
38754).

9­
27
9.0
­
Technology
Options
9.7.2
BCT
In
deciding
whether
to
adopt
more
stringent
limitations
for
BCT
than
BPT,
EPA
considered
whether
there
are
technologies
that
achieve
greater
removals
of
conventional
pollutants
than
adopted
for
BPT,
and
whether
those
technologies
are
cost­
reasonable
under
the
standards
established
by
the
CWA.
EPA
generally
refers
to
the
decision
criteria
as
the
 
BCT
cost
test. 
EPA
is
promulgating
effluent
limitations
for
conventional
parameters
(
e.
g.,
pH,
TSS,
oil
and
grease)
equivalent
to
BPT
for
this
subcategory
because
it
identified
no
technologies
that
can
achieve
greater
removals
of
conventional
pollutants
than
the
selected
BPT
technology
basis
that
also
pass
the
BCT
cost
test.
EPA
evaluated
the
addition
of
ultrafiltration
technology
to
the
BPT
technology
basis
as
a
means
to
obtain
further
oil
and
grease
reductions.
However,
this
technology
option
failed
the
BCT
cost
test.
For
a
more
detailed
description
of
the
BCT
cost
test
and
details
on
EPA s
analysis,
see
Chapter
4
of
the
EEBA.

9.7.3
BAT
EPA
proposed
to
control
toxic
and
nonconventional
pollutants
by
establishing
BAT
limitations
based
on
Option
6
technology.
As
described
in
Section
9.7.1,
EPA
has
decided
not
to
establish
BAT
toxic
and
nonconventional
limitations
based
on
the
Option
6
technology.
While
the
BPT
limitations
are
cost
reasonable,
the
additional
costs
associated
with
compliance
with
Option
6­
generated
BAT
limitations
are
not
warranted.
EPA
has
determined
that
these
costs,
primarily
monitoring
costs,
are
not
warranted
in
view
of
the
small
quantity
of
additional
effluent
reduction
(
if
any)
the
BAT
limitations
would
produce.
As
explained
above,
EPA
has
determined
that
the
BPT
limitation
on
oil
and
grease
(
as
HEM)
will
effectively
control
toxic
and
nonconventional
discharges
in
Oily
Wastes
Subcategory
process
wastewaters.
EPA
has
not
identified
any
more
stringent
economically
achievable
treatment
technology
option
beyond
BPT
technology
(
Option
6)
that
it
considered
to
represent
BAT
level
of
control
applicable
to
Oily
Wastes
Subcategory
facilities.

For
the
reasons
explained
above,
EPA
has
concluded
that
it
should
not
establish
BAT
limitations
for
specific
pollutant
parameters
for
Oily
Waste
operations.
EPA
notes
that
permit
writers
retain
the
authority
to
establish,
on
a
case­
by­
case
basis
under
Section
301(
b)(
1)(
C)
of
the
CWA,
toxic
effluent
limitations
that
are
necessary
to
meet
state
water
quality
standards.

9.7.4
NSPS
EPA
is
promulgating
NSPS
that
would
control
pH
and
the
same
conventional
pollutants
controlled
at
the
BPT
and
BCT
levels.
The
selected
technology
basis
for
NSPS
for
this
subcategory
for
the
final
rule
is
Option
6.
This
is
unchanged
from
the
proposal.
EPA
projects
no
barrier
to
entry
for
new
source
direct
dischargers
associated
with
Option
6
because:
(
1)
Option
6
technology
is
currently
used
at
existing
direct
dischargers
(
i.
e.,
Option
6
technology
is
technically
available),
and
(
2)
there
is
no
barrier
to
entry
for
new
sources.

9­
28
9.0
­
Technology
Options
EPA
evaluated
the
economic
impacts
for
existing
direct
dischargers
associated
with
compliance
with
limitations
based
on
Option
6
and
found
Option
6
to
be
economically
achievable
(
no
closures
projected).
EPA
expects
compliance
costs
to
be
lower
for
new
sources
as
new
sources
can
use
Option
6
technology
without
incurring
retrofitting
costs
(
as
is
required
for
some
existing
sources).
Additionally,
EPA
projects
no
barrier
to
entry
for
Oily
Wastes
NSPS
based
on
the
Option
6
technology
because
approximately
97
percent
of
Oily
Wastes
direct
dischargers
have
after­
tax
compliance
costs
less
than
1
percent
of
revenue
and
3
percent
have
after­
tax
compliance
costs
between
1
to
3
percent
of
revenue.

In
addition,
EPA
also
evaluated
and
rejected
more
stringent
technology
options
for
Oily
Wastes
NSPS
(
i.
e.,
Options
8
and
10).
EPA
reviewed
its
database
for
the
Option
8
and
10
technologies
and
found
that
the
database
for
Option
8
and
10
technologies
is
insufficient
(
i.
e.,
no
available
data)
or
the
costs
are
not
commensurate
with
the
pollutant
removals
(
see
66
FR
457).

Consequently,
EPA
selected
Option
6
technology
as
the
basis
for
NSPS
in
the
Oily
Wastes
Subcategory.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

In
addition,
EPA
also
evaluated
and
rejected
more
stringent
technology
options
for
Oily
Wastes
NSPS
(
i.
e.,
Options
8
and
10).
EPA
reviewed
its
database
for
the
Option
8
and
10
technologies
and
found
no
available
data
for
Option
8
and
10
technologies.
Since
EPA's
database
did
not
contain
Option
10
treatability
data
from
Oily
Wastes
facilities,
EPA
considered
transferring
limitations
for
Option
10
from
the
Shipbuilding
Dry
Dock
or
Railroad
Line
Maintenance
Subcategories.
EPA
ultimately
rejected
this
approach,
however,
because
influent
wastewaters
in
the
Shipbuilding
Dry
Dock
and
Railroad
Line
Maintenance
Subcategories
are
generally
less
concentrated
and
contain
less
pollutants
than
wastewaters
discharged
by
Oily
Wastes
facilities.

9.7.5
PSES
EPA
evaluated
the
same
technology
options
for
indirect
dischargers
in
the
Oily
Wastes
Subcategory
as
for
direct
dischargers
in
the
subcategory.
For
the
final
rule,
EPA
considered
the
same
option
as
evaluated
for
BAT
(
i.
e.,
Option
6).
EPA
did
not
further
evaluate
Options
5,
7,
and
8
for
the
final
rule
for
the
same
reasons
as
explained
for
BPT
above.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
6.

EPA
proposed
to
establish
PSES
for
existing
indirect
dischargers
in
the
Oily
Wastes
Subcategory
based
on
the
Option
6
technology
(
i.
e.,
the
same
technology
basis
that
is
being
promulgated
for
BPT/
BCT/
NSPS
for
this
subcategory)
with
a
 
low­
flow 
exclusion
of
2
MGY
to
reduce
economic
impacts
on
small
businesses
and
administrative
burden
for
control
authorities.
Based
on
the
revisions
and
corrections
to
the
EPA
Costs
&
Loadings
Model
9­
29
9.0
­
Technology
Options
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
and
previously
discussed,
EPA
determined
that
the
toxic
pollutant
reductions
are
very
expensive
in
dollars
per
toxic
pounds
removed.
The
cost­
effectiveness
value
(
in
1981$)
for
Option
6
for
indirect
dischargers
in
the
Oily
Wastes
Subcategory
is
in
excess
of
$
3,500/
PE
removed.
This
suggests
that
the
technology
is
not
truly
 
available. 
EPA
has
determined
that
Option
6
technology
with
a
2­
MGY
low­
flow
cutoff
is
not
the
best
available
technology
economically
achievable
for
existing
indirect
dischargers
in
the
Oily
Wastes
Subcategory.
Therefore,
EPA
is
not
establishing
PSES
for
this
subcategory
based
on
Option
6
technology
with
a
2­
MGY
low­
flow
cutoff.

As
discussed
in
the
June
2002
NODA
(
67
FR
38804),
EPA
also
considered
alternative
options
for
which
economic
impacts
could
be
less
costly
than
Option
6
technology
with
a
2­
MGY
low­
flow
cutoff.
These
options
potentially
have
compliance
costs
more
closely
aligned
with
toxic
pollutant
reductions.
EPA
considered
the
following
alternative
options
for
the
final
rule:

 
Option
A:
No
regulation;
and
 
Option
B:
Option
6
with
a
higher
low­
flow
exclusion.

As
discussed
in
the
NODA,
preamble
to
the
final
rule,
and
Sections
11.0
and
12.0,
based
on
comments,
EPA
has
revised
its
methodology
for
estimating
compliance
costs
and
pollutant
loadings
for
Option
6
with
a
higher
low­
flow
exclusion
(
Option
B).
Using
information
from
this
revised
analysis,
EPA
concludes
that
none
of
the
alternative
low­
flow
exclusions
(
even
as
high
as
6.25
MGY)
represented
 
available
technology 
because
the
costs
associated
with
these
alternatives
were
not
commensurate
with
the
projected
toxic
pollutants
reductions.
Therefore,
EPA
is
not
establishing
PSES
for
existing
indirect
dischargers
in
the
Oily
Wastes
Subcategory
(
Option
A).
Since
EPA
did
not
identify
another
technology
basis
that
was
more
cost­
effective,
EPA
is
not
promulgating
PSES
for
existing
indirect
dischargers
in
the
Oily
Wastes
Subcategory.
These
facilities
remain
subject
to
the
General
Pretreatment
Standards
(
40
CFR
403)
and
local
limits,
as
applicable.

9.7.6
PSNS
EPA
proposed
to
establish
PSNS
for
indirect
dischargers
in
the
Oily
Wastes
Subcategory
based
on
the
Option
6
technology
(
i.
e.,
the
same
technology
basis
that
is
being
promulgated
for
NSPS
for
this
subcategory)
with
a
 
low­
flow 
exclusion
of
2
MGY
to
reduce
economic
impacts
on
small
businesses
and
reduce
administrative
burden
to
POTWs.

For
the
final
rule,
EPA
evaluated
setting
Oily
Wastes
PSNS
based
on
Option
6
technology
and
assessed
the
financial
burden
of
Oily
Wastes
PSNS
based
on
Option
6
technology
on
new
Oily
Wastes
indirect
dischargers.
Specifically,
EPA's
 
barrier­
to­
entry'
analysis
identified
whether
Oily
Wastes
PSNS
based
on
Option
6
technology
would
pose
sufficient
financial
burden
on
new
Oily
Wastes
facilities
to
constitute
a
material
barrier
to
entry
into
the
MP&
M
Point
Source
Category.

9­
30
9.0
­
Technology
Options
EPA
projects
a
barrier
to
entry
for
Oily
Waste
PSNS
based
on
Option
6
technology
as
approximately
because
1
percent
of
Oily
Waste
indirect
dischargers
have
after­
tax
compliance
costs
between
1
to
3
percent
of
revenue
and
5
percent
have
after­
tax
compliance
costs
between
3
to
5
percent
of
revenue.
Consequently,
EPA
rejected
Option
6
technology
as
the
basis
for
PSNS
in
the
Oily
Wastes
Subcategory.
EPA
has
selected
 
no
further
regulation 
for
new
Oily
Wastes
indirect
dischargers
and
is
not
revising
PSNS
for
new
Oily
Wastes
indirect
dischargers.
Wastewater
discharges
to
POTWs
from
facilities
in
this
subcategory
will
remain
regulated
by
local
limits
and
General
Pretreatment
Standards
(
Part
403),
as
applicable.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

Railroad
Line
Maintenance
Subcategory
EPA
is
not
establishing
limitations
or
standards
for
any
facilities
that
would
have
been
subject
to
this
subcategory.
Permit
writers
and
control
authorities
will
establish
controls
using
BPJ
to
regulate
wastewater
discharges
from
these
facilities.

9.8.1
BPT
At
proposal,
EPA
evaluated
four
technology
options
for
the
Railroad
Line
Maintenance
(
RRLM)
Subcategory.
These
included
Options
7
and
8,
which
are
described
in
detail
in
Section
9.7.1,
and
Options
9
and
10,
described
below.
In
addition,
for
the
final
rule,
EPA
evaluated
Option
6
for
this
subcategory
(
see
Section
9.7.1).

Option
9
Option
9
consists
of
end­
of­
pipe
chemical
emulsion
breaking
followed
by
dissolved
air
flotation
(
DAF)
to
remove
flocculated
oils.
This
treatment
train
is
demonstrated
in
both
the
Shipbuilding
Dry
Dock
and
RRLM
Subcategories
and
effectively
removes
emulsified
oils
and
suspended
solids.
Option
9
also
includes
contract
hauling
of
organic
solvent­
bearing
wastewater
instead
of
discharge.

Option
10
Option
10
consists
of
the
end­
of­
pipe
treatment
technologies
included
in
Option
9
plus
in­
process
flow
control
and
pollution
prevention
technologies,
which
allow
for
recovery
and
reuse
of
materials
along
with
water
conservation.
The
specific
Option
10
in­
process
technologies
include:

 
Two­
stage
countercurrent
cascade
rinsing
for
all
flowing
rinses;

 
Centrifugation
and
recycling
of
painting
water
curtains;
and
9­
31
9.8
9.0
­
Technology
Options
 
Centrifugation,
pasteurization,
and
recycling
of
water
soluble
machining
coolants.

Option
Selection
For
the
final
rule,
EPA
evaluated
setting
BPT
limitations
for
two
pollutants,
TSS
and
oil
and
grease
(
as
HEM),
for
direct
dischargers
in
the
RRLM
Subcategory
based
on
a
different
technology
basis
from
that
proposed
in
2001.
EPA
proposed
Option
10
technology
as
the
technology
basis
for
BPT.
However,
as
discussed
in
the
NODA,
EPA
considered
promulgating
limitations
for
the
final
rule
based
on
the
Option
6
technology
for
the
RRLM
Subcategory
(
see
67
FR
38804).
Option
6
technology
includes
the
following:
(
1)
in­
process
flow
control
and
pollution
prevention;
and
(
2)
oil/
water
separation
by
chemical
emulsion
breaking
and
skimming
(
see
Section
9.7.1
for
additional
details
on
the
Option
6
technology).

For
the
RRLM
Subcategory,
EPA
changed
the
technology
basis
considered
for
the
final
rule
based
on
comments
and
data
submitted
by
the
American
Association
of
Railroads
(
AAR).
This
organization
is
a
trade
association
that
currently
represents
all
facilities
in
this
subcategory.
As
discussed
in
the
NODA
(
67
FR
38755),
for
each
RRLM
direct
discharging
facility
known
to
them,
AAR
provided
current
permit
limits,
treatment­
in­
place,
and
summarized
information
on
each
facility s
measured
monthly
average
and
daily
maximum
values.
AAR
also
provided
a
year s
worth
of
long­
term
monitoring
data
for
each
facility
(
see
Section
15.1
of
the
rulemaking
record
for
the
AAR
surveys).
This
data
shows
that,
contrary
to
EPA s
initial
findings
in
the
2001
proposal,
most
RRLM
direct
dischargers
treat
their
wastewater
by
chemical
emulsion
breaking/
oil
skimming
(
Option
6).
Based
on
this
updated
information,
EPA
rejected
Option
10
as
the
technology
basis
for
BPT.
The
2001
proposal
also
contains
detailed
discussions
on
why
EPA
rejected
BPT
limitations
based
on
other
BPT
technology
options
(
see
66
FR
451).
The
information
in
the
rulemaking
record
provides
no
basis
for
EPA
to
change
this
conclusion.

As
previously
discussed,
after
publication
of
the
June
2002
NODA,
EPA
also
conducted
another
review
of
all
RRLM
facilities
in
the
MP&
M
survey
database
to
determine
the
destination
of
discharged
wastewater
(
i.
e.,
either
directly
to
surface
waters
or
indirectly
to
POTWs
or
both)
and
the
applicability
of
the
final
rule
to
discharged
wastewaters.
As
a
result
of
this
review,
EPA
determined
that
its
survey
database
did
not
accurately
represent
direct
dischargers
in
this
subcategory.
Consequently,
for
the
final
rule,
EPA
used
the
information
supplied
by
AAR
as
a
basis
for
its
analyses
and
conclusions
on
direct
dischargers
in
this
subcategory.

AAR
provided
information
on
27
facilities.
EPA
reviewed
the
information
on
each
of
these
facilities
to
ensure
they
were
direct
dischargers,
discharged
wastewaters
resulting
from
operations
subject
to
this
final
rule,
and
discharged
"
process"
wastewaters
as
defined
by
the
final
rule.
As
a
result
of
this
review,
EPA
concluded
that
18
of
the
facilities
for
which
AAR
provided
information
do
not
directly
discharge
wastewaters
exclusively
from
oily
operations
(
see
Section
V.
A
of
the
preamble
to
the
final
rule).
Therefore,
EPA's
final
database
consists
of
data
for
nine
direct
discharging
RRLM
facilities.
EPA
considered
promulgating
BPT
limitations
for
9­
32
9.0
­
Technology
Options
these
nine
direct
discharging
RRLM
facilities
based
on
the
Option
6
technology.
The
Agency
made
the
following
conclusions
during
its
evaluation
of
Option
6
for
this
subcategory.

First,
this
technology
is
readily
applicable
to
all
facilities
in
the
RRLM
Subcategory.
All
direct
dischargers
in
the
RRLM
Subcategory
currently
use
wastewater
treatment
equivalent
or
better
than
chemical
emulsion
breaking/
oil
skimming
(
Option
6).
Second,
EPA
estimates
that
compliance
with
BPT
limitations
based
on
Option
6
technology
will
result
in
no
closures
of
the
existing
direct
dischargers
in
the
RRLM
Subcategory.
Moreover,
none
of
the
facilities
identified
by
AAR
are
small
businesses
as
defined
by
the
Small
Business
Administration
(
SBA).
Third,
most
of
the
RRLM
facilities
identified
by
AAR
have
NPDES
daily
maximum
permit
limitations
for
oil
and
grease
(
as
HEM)
and
TSS
as
15
and
45
mg/
L,
respectively.
Based
on
AAR
survey
information,
EPA
concludes
that
these
oil
and
grease
(
as
HEM)
and
TSS
daily
maximum
limits
represent
the
average
of
the
best
performances
of
facilities
utilizing
Option
6
technology.

EPA
evaluated
the
compliance
costs
and
load
reductions
associated
with
establishing
BPT
daily
maximum
limitations
equivalent
to
15
and
45
mg/
L
for
oil
and
grease
(
as
HEM)
and
TSS,
respectively.
EPA
concluded
that
all
of
the
facilities
identified
by
AAR
currently
meet
a
daily
maximum
oil
and
grease
limit
of
15
mg/
L
and
most
currently
monitor
once
per
month.
Therefore,
EPA
estimates
no
pollutant
load
reductions
and
minimal
incremental
annualized
compliance
costs
for
the
monitoring
associated
with
a
BPT
daily
maximum
limitation
equivalent
to
15
mg/
L
for
oil
and
grease
(
as
HEM).
For
TSS,
with
the
exception
of
one
facility,
all
RRLM
facilities
identified
by
AAR
currently
meet
a
daily
maximum
limit
of
45
mg/
L.
For
this
one
facility,
EPA
estimates
the
TSS
pollutant
loadings
reductions
associated
with
a
BPT
daily
maximum
limitation
equivalent
to
45
mg/
L
to
be
less
than
1
pound
of
TSS
per
day.
Given
the
fact
that
the
few
facilities
in
this
subcategory
are
already
essentially
achieving
the
limitations
under
consideration,
EPA
has
determined
that
additional
national
regulation
is
not
warranted.
As
a
result
of
this
analysis,
EPA
concludes
that
it
is
more
appropriate
to
address
permits
limitations
for
this
industry
on
a
case­
by­
case
basis
and
that
additional
national
regulation
of
direct
discharges
in
the
RRLM
Subcategory
at
this
time
is
unwarranted.

9.8.2
BCT
In
deciding
whether
to
adopt
more
stringent
limitations
for
BCT
than
BPT,
EPA
considers
whether
there
are
technologies
that
achieve
greater
removals
of
conventional
pollutants
than
adopted
for
BPT,
and
whether
those
technologies
are
cost­
reasonable
under
the
standards
established
by
the
CWA.
EPA
generally
refers
to
the
decision
criteria
as
the
 
BCT
cost
test. 
For
a
more
detailed
description
of
the
BCT
cost
test
and
details
of
EPA s
analysis,
see
Chapter
4
of
the
EEBA.

For
the
reasons
discussed
above,
EPA
is
not
establishing
BCT
limitations
for
the
RRLM
Subcategory.

9­
33
9.0
­
Technology
Options
9.8.3
BAT
As
proposed,
EPA
is
not
establishing
BAT
regulations
for
the
RRLM
Subcategory.
EPA
did
not
propose
BAT
regulations
because
the
Agency
concluded
that
facilities
in
this
subcategory
discharge
very
few
pounds
of
toxic
pollutants.
EPA
estimates
that
six
facilities
discharge
34
PE
per
year
to
surface
waters,
or
about
6
PE
per
year
per
facility.
The
Agency
based
the
loadings
calculations
on
EPA
sampling
data,
which
found
very
few
priority
toxic
pollutants
at
treatable
levels
in
raw
wastewater.
EPA
has
received
no
data
or
information
during
the
rulemaking
that
contradicts
these
conclusions.
Therefore,
nationally
applicable
regulations
for
toxic
and
nonconventional
pollutants
are
unnecessary
at
this
time
and
direct
dischargers
will
remain
subject
to
permit
limitations
for
toxic
and
nonconventional
pollutants
established
on
a
case­
by­
case
basis
using
BPJ.

9.8.4
NSPS
EPA
proposed
setting
NSPS
based
on
Option
10
technology
for
this
subcategory.
For
the
final
rule,
EPA
considered
setting
RRLM
NSPS
based
on
Option
10
technology
and
assessed
the
financial
burden
of
RRLM
NSPS
based
on
Option
10
technology
on
new
RRLM
direct
dischargers.
Specifically,
EPA s
 
barrier­
to­
entry 
analysis
identified
whether
RRLM
NSPS
based
on
Option
10
technology
would
pose
sufficient
financial
burden
as
to
constitute
a
material
barrier
to
entry
into
the
MP&
M
Point
Source
Category.

EPA
projects
no
barrier
to
entry
for
RRLM
NSPS
based
on
Option
10
technology
because:
(
1)
Option
10
technology
is
currently
used
at
existing
RRLM
direct
dischargers
(
i.
e.,
Option
10
technology
is
technically
available),
and
(
2)
all
RRLM
direct
dischargers
have
new
source
compliance
costs
that
are
less
than
1
percent
of
revenue.
However,
EPA
is
not
promulgating
RRLM
NSPS
based
on
the
Option
10
technology
because
EPA
concludes
that
it
is
more
appropriate
to
address
limitations
for
this
industry
on
a
case­
by­
case
basis
and
that
national
regulation
of
direct
discharges
in
the
RRLM
Subcategory
at
this
time
is
unwarranted.
See
Section
11.0
for
a
description
of
how
these
new
source
compliance
costs
were
developed
and
Chapter
9
of
the
EEBA
for
a
description
of
the
framework
EPA
used
for
the
barrier­
to­
entry
analysis
and
general
discussion
of
the
results.

9.8.5
PSES
and
PSNS
EPA
proposed
not
to
establish
pretreatment
standards
for
existing
and
new
indirect
dischargers
in
the
RRLM
Subcategory
based
on
the
small
quantity
of
toxic
pollutants
discharged
to
the
environment
(
after
POTW
treatment)
by
facilities
in
this
subcategory
(
i.
e.,
approximately
2
PE
removed
annually
per
facility
(
see
66
FR
470­
471)).
For
the
same
reasons
set
out
in
the
2001
proposal,
EPA
is
not
promulgating
pretreatment
standards
for
existing
or
new
indirect
dischargers
in
this
subcategory.
These
facilities
remain
subject
to
the
General
Pretreatment
Standards
(
40
CFR
403)
and
local
limits.

9­
34
9.0
­
Technology
Options
9.9
Shipbuilding
Dry
Dock
Subcategory
EPA
is
not
establishing
limitations
or
standards
for
any
facilities
that
would
have
been
subject
to
this
subcategory.
Permit
writers
and
control
authorities
will
establish
controls
using
BPJ
to
regulate
wastewater
discharges
from
these
facilities.

9.9.1
BPT/
BCT/
BAT/
NSPS
EPA
evaluated
four
technology
options
for
the
Shipbuilding
Dry
Dock
(
SDD)
Subcategory.
These
include
Options
7
and
8,
which
are
described
in
detail
in
Section
9.7.1,
and
Options
9
and
10,
which
are
described
in
detail
in
Section
9.8.1.

As
discussed
in
the
2001
proposal
(
66
FR
451),
EPA
dropped
Options
7
and
9
from
further
consideration
because
Options
8
and
10,
respectively,
cost
less
and
provided
greater
pollutant
removals.
EPA
also
evaluated
and
rejected
a
more
stringent
technology
option
for
SDD
NSPS
(
i.
e.,
Option
8).
EPA
reviewed
its
database
for
the
Option
8
technology
and
found
that
no
available
data
or
possibility
of
data
transfer
from
the
other
oily
subcategories
are
available
because
ultrafiltration
does
not
consistently
show
a
better
removal
than
Option
10
to
support
a
determination
that
NSPS
based
on
Option
8
standards
are
technically
achievable.
EPA
concluded
that
Option
8
does
not
represent
the
best
practicable
control
technology.
Therefore,
for
the
final
rule,
EPA
considered
only
Option
10
as
the
basis
for
limitations
for
the
SDD
Subcategory.
See
Sections
11.0
and
12.0
for
the
final
estimated
compliance
costs
and
pollutant
loadings
for
Option
10.

At
the
time
of
the
2001
proposal,
EPA
identified
six
direct
discharging
SDD
facilities
with
multiple
discharges.
Based
on
the
information
in
the
database
at
that
time,
discharges
from
these
facilities
contained
minimal
concentrations
of
toxic
organic
and
metals
pollutants
(<
9
PE/
facility),
but
substantial
quantities
of
conventional
pollutants,
particularly
oil
and
grease.
Consequently,
EPA
proposed
to
establish
BPT
limitations
and
NSPS
for
only
two
pollutants,
TSS
and
oil
and
grease
(
as
HEM),
for
direct
dischargers
in
the
SDD
Subcategory
based
on
Option
10
technology.
This
technology
includes
the
following:
(
1)
in­
process
flow
control
and
pollution
prevention,
and
(
2)
oil/
water
separation
by
chemical
emulsion
breaking
and
oil/
water
separation
by
dissolved
air
flotation
(
see
Section
9.8.1).
EPA
proposed
this
technology
basis
because
some
existing
SDD
facilities
use
this
technology
and
it
projected
significant
reductions
in
conventional
pollutants
and
determined
that
these
reductions
were
cost
reasonable.

Following
proposal,
EPA
received
comments
and
supporting
data
indicating
that
its
estimates
of
current
pollutant
discharges
from
this
subcategory
were
overestimated.
In
particular,
commentors
claimed
that
current
discharges
of
oil
and
grease
were
minimal
and
that
national
regulation
was
not
warranted
for
this
subcategory.

For
the
final
rule,
EPA
incorporated
the
additional
information
provided
by
commentors
into
its
analysis.
EPA
continues
to
conclude
that
there
are
six
direct
discharging
SDD
facilities.
However,
EPA
now
concludes
that
direct
discharges
from
these
facilities
9­
35
9.0
­
Technology
Options
generally
contain
minimal
levels
of
all
pollutants.
In
particular,
EPA s
database
indicates
that
regulation
of
oil
and
grease
in
direct
discharges
from
SDD
facilities
is
unwarranted
because
current
oil
and
grease
discharges
from
these
facilities
are
not
detectable
(<
5
mg/
L)
or
nearly
not
detectable.
EPA
has
similarly
determined
that
it
should
not
establish
nationally
applicable
limitations
and
standards
for
TSS
because
TSS
discharges
are,
on
average,
minimal.
The
data
show
that
TSS
discharges
may
increase
episodically,
particularly
when
the
dry
dock
is
performing
abrasive
blasting
operations
cleaning.
However,
EPA
has
concluded
that
these
episodic
discharges
from
six
facilities
do
not
warrant
national
regulation.

Therefore,
nationally
applicable
regulations
for
new
and
existing
SDD
direct
dischargers
are
unnecessary
at
this
time
and
these
facilities
will
remain
subject
to
permit
limitations
established
on
a
case­
by­
case
basis
using
BPJ.

9.9.2
PSES
and
PSNS
EPA
proposed
not
to
establish
pretreatment
standards
for
existing
and
new
indirect
dischargers
in
the
SDD
Subcategory
based
on
the
small
number
of
facilities
in
this
subcategory
and
on
the
small
quantity
of
toxic
pollutants
removed
by
the
technology
options
evaluated
by
EPA
at
proposal
(
i.
e.,
less
than
26
PE
removed
annually
per
facility
(
see
66
FR
471)).
For
the
same
reasons
set
out
in
the
2001
proposal,
EPA
is
not
promulgating
pretreatment
standards
for
existing
or
new
indirect
dischargers
in
this
subcategory.
These
facilities
remain
subject
to
the
General
Pretreatment
Standards
(
40
CFR
403)
and
local
limits.

9.10
Summary
of
Technology
Options
Considered
and
Selected
for
the
Final
MP&
M
Rule
Table
9­
1
summarizes
all
of
the
technology
options
considered
for
the
MP&
M
subcategories
for
either
the
proposed
or
final
rules.
Table
9­
2
summarizes
EPA s
selected
technology
bases
for
the
final
rule.

9­
36
9.0
­
Technology
Options
9­
37
Table
9­
1
Technology
Options
by
Subcategory
Treatment
or
Source
Reduction
Technology
Technology
Options
Considered
for
the
General
Metals,
Metal
Finishing
Job
Shops,
Printed
Wiring
Board,
Steel
Forming
and
Finishing,
and
Non­

Chromium
Anodizing
Subcategoriesa
Technology
Options
Considered
for
the
Oily
Wastes,
Shipbuilding
Dry
Dock,
and
Railroad
Line
Maintenance
Subcategoriesb
1
2
2S
3
4
413
to
433
Upgrade
Local
Limits
to
433
Upgrade
5
6
7
8
9
10
Chemical
Precipitation
 
 
 
 
 
 
 
Gravity
Clarification
for
Metal
Hydroxide
Removal
 
 
 
 
 
Microfiltration
for
Metal
Hydroxide
Removal
 
 
Chemical
Emulsion
Breaking
Followed
by
Gravity
Separation
for
Oil
Removal
 
 
 
 
 
 
 
Ultrafiltration
for
Oil
Removal
 
 
 
 
Chemical
Emulsion
Breaking
Followed
by
Dissolved
Air
Flotation
for
Oil
Removal
 
 
Alkaline
Chlorination
for
Cyanide
Removal
 
 
 
 
 
 
 
Chemical
Reduction
of
Hexavalent
Chromium
 
 
 
 
 
 
 
Chelation
Breaking/
Precipitation
to
Remove
Complexed
Metals
 
 
 
 
 
 
 
Contract
Hauling
of
Organic
Solvent­
Bearing
Wastewater
Instead
of
Discharge
 
 
 
 
 
 
 
 
 
 
 
 
 
Countercurrent
Cascade
Rinsing
to
Conserve
Water
 
 
 
 
 
 
Centrifugation
of
Painting
Water
Curtains
to
Extend
Life
 
 
 
 
 
 
Centrifugation
and
Pasteurization
of
Machining
Coolants
to
Extend
Life
 
 
 
 
 
 
Sand
Filter
to
Remove
Additional
Suspended
Solids
 
Sludge
Dewatering
and
Disposal
 
 
 
 
 
 
 
 
 
aSee
Section
9.2.2
for
a
discussion
of
BCT
options
considered
for
the
General
Metals
Subcategory.

bEPA
evaluated
Option
5
for
the
Oily
Wastes
Subcategory
only,
Option
6
for
the
Oily
Wastes
and
Railroad
Line
Maintenance
Subcategories
only,
and
Options
9
and
10
for
the
Shipbuilding
Dry
Dock
and
Railroad
Line
Maintenance
Subcategories
only.
See
Sections
9.7.2,
9.8.2,
and
9.9.1
for
discussions
of
BCT
options
considered
for
these
subcategories.
9.0
­
Technology
Options
Table
9­
2
Summary
of
Technology
Bases
for
the
Final
Rule
Subcategory
Regulatory
Level
Technology
Basis
General
Metals
BPT/
BCT/
BAT/
NSPS
No
new
or
revised
limitations
or
standards
established
PSES/
PSNS
No
new
or
revised
standards
established
Metal
Finishing
Job
Shops
BPT/
BCT/
BAT/
NSPS
No
new
or
revised
limitations
or
standards
established
PSES/
PSNS
No
new
or
revised
standards
established
Printed
Wiring
Board
BPT/
BCT/
BAT/
NSPS
No
new
or
revised
limitations
or
standards
established
PSES/
PSNS
No
new
or
revised
standards
established
Non­
Chromium
Anodizing
BPT/
BCT/
BAT/
NSPS
No
new
or
revised
limitations
or
standards
established
PSES/
PSNS
No
new
or
revised
standards
established
Steel
Forming
and
Finishing
BPT/
BCT/
BAT/
NSPS
No
new
or
revised
limitations
or
standards
established
PSES/
PSNS
No
new
or
revised
standards
established
Oily
Wastes
BPT/
BCT/
NSPS
Option
6:
In­
process
pollution
prevention,
recycling,
and
water
conservation
methods;
and
chemical
emulsion
breaking
followed
by
oil/
water
separation
BAT
No
new
or
revised
limitations
established
PSES/
PSNS
No
new
or
revised
standards
established
Railroad
Line
Maintenance
BPT/
BCT/
BAT/
NSPS
No
new
or
revised
limitations
or
standards
established
PSES/
PSNS
No
new
or
revised
standards
established
Shipbuilding
Dry
Dock
BPT/
BCT/
BAT/
NSPS
No
new
or
revised
limitations
or
standards
established
PSES/
PSNS
No
new
or
revised
standards
established
9­
38
9.0
­
Technology
Options
9­
39
Figure
9­
1.
­
Pipe
Treatment
Train
for
Options
1
and
2
Considered
for
the
Following
Subcategories:

General
Metals,
Metal
Finishing
Job
Shops,
Non­
Chromium
Anodizing,
Printed
Wiring
Board,
and
Steel
Forming
and
Finishing
End­
of
9.0
­
Technology
Options
9­
40
Figure
9­
2.
­
Process
Water
Use
Reduction
Technologies
for
Options
2
and
4
Considered
for
the
Following
Subcategories:
General
Metals,
Metal
Finishing
Job
Shops,
Non­
Chromium
Anodizing,
Printed
Wiring
Board,
and
Steel
Forming
and
Finishing
In
9.0
­
Technology
Options
9­
41
Figure
9­
3.
­
Pipe
Treatment
Train
for
Options
3
and
4
Considered
for
the
Following
Subcategories:

General
Metals,
Metal
Finishing
Job
Shops,
Non­
Chromium
Anodizing,
Printed
Wiring
Board,
and
Steel
Forming
and
Finishing
End­
of
9.0
­
Technology
Options
9­
42
Figure
9­
4.
nd­
of­
Pipe
Treatment
Train
for
Options
5
and
6
Considered
for
the
Following
Subcategories:
Oily
Wastes
and
Railroad
Line
Maintenance
Figure
9­
5.
­
Pipe
Treatment
Train
for
Option
7
and
8
Considered
for
the
Following
Subcategories:
Oily
Wastes,
Railroad
Line
Maintenance,
Shipbuilding
Dry
Dock
E
End­
of
9.0
­
Technology
Options
9­
43
Figure
9­
6.
nd­
of­
Pipe
Treatment
Train
for
Options
9
and
10
Considered
for
the
Following
Subcategories:
Railroad
Line
Maintenance
and
Shipbuilding
Dry
Dock
E
