Page
1
of
3
Memorandum
From:
Carey
A.
Johnston,
P.
E.
USEPA/
OW/
OST
ph:
(
202)
566
1014
johnston.
carey@
epa.
gov
To:
Public
Record
for
Requirements
for
Cooling
Water
Intake
Structures
at
Phase
III
Facilities
DCN
XXX,
Section
XXX
EPA
Docket
Number
OW­
2004­
0002
(
www.
epa.
gov/
edockets/)

Date:
March
11,
2004
Re:
Mobile
Offshore
Drilling
Units
NPDES
Coverage
Overview
EPA
is
required
by
a
court
order
to
develop
regulations
for
cooling
water
intakes
for
a
wide
range
of
facilities,
and
must
propose
"
Phase
III"
requirements
by
November
1,
2004
(
see
http://
www.
epa.
gov/
ost/
316b/).
EPA
summarized
some
of
the
major
issues
related
to
seawater
intakes
for
mobile
offshore
drilling
units
(
MODUs)
and
fixed
platforms
in
the
following
document
(
http://
www.
epa.
gov/
waterscience/
316b/
technical/
ch6.
pdf).

MODUs
are
specialized
vessels
used
for
drilling
and
servicing
offshore
oil
and
gas
wells
and
they
move
from
location
to
location
to
drill
both
exploratory
and
production
wells.
There
are
five
main
types
of
MODUs
operating
in
areas
under
U.
S.
jurisdiction:
drillships,
semi­
submersibles,
jack­
ups,
submersibles
and
drilling
barges.
Some
of
these
vessels
(
e.
g.,
jack­
ups,
semi­
submersibles)
are
not
self­
propelled
and
must
be
towed
from
location
to
location.
Once
on
location,
these
facilities
may
use
sea
water
intakes
to
help
fix
their
location
so
that
the
riser
can
be
securely
lowered
to
the
seabed
for
drilling.

The
seawater
intake
systems
on
MODUs
may
serve
multiple
functions.
In
addition
to
providing
cooling
water
for
diesel
engines,
drawworks
brakes
and
anchor
windlass
brakes,
air
compressors
and
hydraulic
units
and
distillers,
these
systems
also
provide
intake
water
for
firemains,
preload
and
ballast
systems
to
help
fix
their
location,
sanitary
and
washdown
systems,
and
desalination
units.
There
are
both
regulatory
and
operational
requirements
that
dictate
interconnection
and
redundancy
of
these
systems,
particularly
with
ballast
and
preload
systems
used
to
help
fix
MODU
location.
Operational
requirements
dictate
high
capacity
pumps
in
order
to
expedite
the
ballasting
or
preloading
of
the
MODU
in
order
to
properly
secure
its
location.
There
may
be
limited
periods
of
time
(
hours
to
days)
when
the
through­
screen
velocities
for
these
ballasting
and
preloading
operations
may
exceed
10
ft/
sec.
1Spackman,
Alan,
2002.
"
Cooling
and
other
Water
Uptake
by
Drilling
Rigs,"
Letter
from
International
Association
of
Drilling
Contractors
to
Mr.
Carey
A.
Johnston,
U.
S.
EPA,
August
5,
2002.

Page
2
of
3
In
order
to
evaluate
costs
for
various
316(
b)
technology
options
and
develop
draft
regulatory
language,
EPA
determined
whether
the
seawater
intake
use
to
secure
the
location
of
a
MODU
occurs
before
or
during
National
Pollutant
Discharge
Elimination
System
(
NPDES)
permit
coverage.
Only
facilities
and
vessels
that
are
required
to
have
an
NPDES
permit
to
discharge
wastewater
would
even
potentially
be
subject
to
requirements
in
the
Phase
III
316(
b)
rulemaking.
In
making
this
determination
EPA
reviewed
Part
122.3(
a)
and
several
NPDES
permits
(
e.
g.,
Western
GOM
permit
(
OCS
General
Permit
No.
GMG290000))
and
coordinated
with
several
internal
experts
on
oil
and
gas
extraction
permitting
(
e.
g.,
Scott
Wilson
(
EPA
Region
6),
Jeff
Smith
and
Ruby
Cooper
(
OWM),
and
Mary
Ellen
Levine
(
OGC)).

The
International
Association
of
Drilling
Contractors
(
IADC)
also
questioned
seawater
intake
use
to
secure
the
location
of
a
MODU
occurs
before
or
during
NPDES
permit
coverage:
1
"
One
issue
which
we
identified
that
we
believe
must
be
resolved
in
the
rulemaking
is
identification
of
the
point
during
the
set­
up
and
termination
of
operations
of
a
MODU
on
an
offshore
lease
that
coverage
under
the
lessees'
NPDES
permit
begins
and
ends.
Most
pre­
load
(
for
jack­
ups)
and
ballasting
(
for
semisubmersibles)
operations
take
place
at
the
time
that
the
rig
arrives
on
the
operating
location,
i.
e.,
before
the
drilling
riser
is
connected
to
the
seabed.
We
would
note
that
similar
operations
would
take
place
if
the
unit
were
moving
into
or
out
of
an
anchorage
between
jobs;
no
NPDES
permit
would
apply
at
such
time."

Regulatory
Determination
The
NPDES
regulations
(
40
CFR
122.3(
a))
exclude
most
vessel
discharges
from
the
NPDES
program.
However,
this
exclusion
does
not
apply
to
discharges
from
MODUs
while
engaged
in
oil
and
gas
exploration
or
development
activities
or
when
secured
to
the
bed
of
the
ocean.
In
particular,
40
CFR
122.3(
a)
states
that
the
following
discharges
do
not
require
NPDES
permits:

Any
discharge
of
sewage
from
vessels,
effluent
from
properly
functioning
marine
engines,
laundry,
shower,
and
galley
sink
wastes,
or
any
other
discharge
incidental
to
the
normal
operation
of
a
vessel.
This
exclusion
does
not
apply
to
rubbish,
trash,
garbage,
or
other
such
materials
discharged
overboard;
nor
to
other
discharges
when
the
vessel
is
operating
in
a
capacity
other
than
as
a
means
of
transportation
such
as
when
used
as
an
energy
or
mining
facility,
a
storage
facility
or
a
seafood
processing
facility,
or
when
secured
to
a
storage
facility
or
a
seafood
processing
facility,
or
when
secured
to
the
bed
of
the
ocean,
contiguous
zone
or
waters
of
the
United
States
for
the
purpose
of
mineral
or
Page
3
of
3
oil
exploration
or
development.

In
general,
there
is
no
single
action,
like
the
anchoring
of
a
vessel,
which
clearly
demarcate
the
end
of
transportation.
Rather,
NPDES
permit
coverage
begins
when
the
MODU
arrives
on
the
lease
(
i.
e.,
when
the
MODU
is
no
longer
being
used
for
navigation).
Permit
authorization
at
a
lease
should
end,
not
when
the
riser
is
disconnected,
but
after
all
operations
associated
with
drilling
are
completed
and
the
MODU
starts
navigating
or
being
transported
to
its
new
location.
MODUs
could
potentially
have
drilling
related
discharges,
such
as
a
bulk
discharge
of
waterbased
drilling
fluids,
after
a
riser
is
disconnected.
Linking
NPDES
authority
to
when
a
MODU
starts
or
stops
navigation
from
one
location
to
another
will
best
fit
all
the
different
MODU
operations
offshore.
Therefore,
NPDES
permit
coverage
cannot
be
linked
to
installation
of
the
riser
as
suggested
by
IADC.

Additionally,
EPA
has
determined
that
the
seawater
intakes
used
to
secure
the
location
of
MODUs
occur
during
NPDES
permit
coverage.
The
seawater
intakes
which
are
used
to
secure
the
location
of
a
MODU
are
not
part
of
the
MODU's
navigational
operations.
Rather,
these
seawater
intakes
are
integral
to
the
MODU's
operations
as
an
energy
facility.
