Boom deployment for industrial applications and general spills
Spill conditions on open water
that involve high volume discharges
from outfalls, along
with the variable flow rates of
rivers, unpredictable wind, and wave
actions, can create their own challenges
for containing spills. Mix in the
different viscosity and solubility properties
of solvents, oils, and fuels and
you have quickly taken the science out
of boom deployment and spill recovery.
Permanent, temporary, and sorbent
booms placed at outfalls, in boat slips,
creeks and ditches, etc., are put in
place with the intent to stop, collect
and recover a petroleum based (oil)
spill. Having booms in place on a permanent
or temporary basis may be
viewed as due diligence. However,
when the combination of unpredictable
conditions exists, spills may travel
beyond the perimeters of containment,
allowing unwanted oil contamination
ranging from a sheen, a continuous
patch, blobs, or an emulsified mixture
of oil and water to migrate downstream.
Due diligence may now
depend on your ability to anticipate
actions to be taken and on your capability
to respond.
Aesthetic improvements that make
outfalls, creeks and storm ditches
pleasing to the eye and the public are
affecting response capability and
increasing corporate liabilities. Recently,
a facility allowed man-made
nests for geese to be installed along
their outfall. As a result, response
efforts may have to be abandoned due
to the intervention of aggressive
wildlife. Shorelines are being groomed
with rocks, gravel and other porous
materials. This makes the installation
of booms that must maintain a seal at
the water’s edge, and address the conditions
of rising and falling water levels,
a challenge.
A common problem for industry is
that many believe the permanentbooms
installed at the outfalls of a
plant will automatically contain all oil
based spills from the facility. Another
oversight appears to be that industries
have not factored in the result of modifications
to existing processes, and
how it can significantly increase corporate
liabilities and scales of impact
to the environment. Many organizations
need to upgrade their action
plans, supplies, equipment and training
to test their response capability and
revisit the time-critical issues for each
location. Practical preparedness and
capability assessments should be conducted
on a seasonal basis.
Modifications made to the containment
systems, emergency response
plans, operating procedures and dedicated
resources need to be matched to
the hierarchy of an event.
Practical preparedness and capability
studies should include ways to:
understand the effects of undercurrents,
vortexing, and the boiling effects
of surface water that may cause oil to
be drawn back into suspension or
remain suspended for some time,
make allowances for changing flow
rates (e.g. seasonal, production),
realize the distance that oil can travel
before surfacing,
estimate enough time to allow oil to
reach the surface of the water,
provide enough area for oil to surface
inside the containment area,
design, test or monitor the effectiveness
of boom selection and deployment,
have supplies, equipment and
trained personnel in place and in a
state of readiness to deal with time-critical
issues.
Identify location-specific response
needs and develop effective prevention
preparedness and response strategies
that will allow responders to react in
good time. Preparedness activities may
include practised techniques, hardline
decisions, as well as appropriate and
immediate actions to be taken that can
make a difference in the outcome of
events. In facilities where a hardline
decision cannot be made to shut down
the production at a process plant for
safety reasons, an on site retention or
emergency pond system may have to
be incorporated as part of a preventive
strategy to control and recover spills.
Know what works and what doesn’t
work. There are no standards for boom
deployment or placement that will
guarantee success when a spill is out of
control. Planning, practice, knowing
your equipment, and water conditions
are critical. Know that working in the
wrong conditions is only wasting time,
resources and the energy of responders,
and may not achieve the desired
results. Move down stream to survey
and select ideal conditions. When you
think you are far enough ahead of the
spill to start setting up, multiply your
distance times three to allow for additional
time to deal with the unexpected.
A better approach would be to
develop a preparedness strategy that
dedicates time, effort and money for
supplies, equipment and training to
deal with each location’s specific
needs. Due to increased environmental
fines, these initiatives should be fully
supported by top management.
Booms can be used as a tool to help
modify conditions, or slow, divert, and
contain spills. They have been used to
slow the high volume discharge from
an outfall and keep the spill in quiet
waters.
A high volume discharge from an
outfall can push and distort a ‘uniformed
U-shaped boom configuration’
into an ‘angled’ or ‘right-angle configuration’.
This distorted shape is a visual
indication that the boom is not performing
to the intended design of containing
a spill. At best, booms in this
position will only provide minimal
containment, help to disperse the effluent,
reduce the velocity of the discharge,
and slow the advance of the
spill. This activity may improve the
retention time and reduce the distance
a spill travels before coming to the surface.
Not all the contaminated spill will
have surfaced inside the containment
area, therefore, a second set or multiple
sets of booms will be required for
back up. Booms may also be used to
divert a spill into manageable areas
where response activities become
more systematic and routine.
The flow rate and retention time are
two of the most important factors in
determining how far a spill will travel
before all the oil reaches the surface. If
the flow rate is too fast, the boom may
hydroplane on top of the water, or set
up vortexing that will cause oil to be
drawn under the boom and escape.
Similar conditions occur if a boom is
pulled or blown too quickly across the
water’s surface.
Booms must be placed in slow
moving or stagnant water conditions to
do their best job. When flow rates are
too fast, responders have two choices:
‘find the right conditions’ or ‘make the
right conditions’. This means that, if
the right conditions do not exist, personnel
must move down stream and
find the ideal conditions or make the
ideal conditions by activating any
downstream water controls to increase
ponding areas and slowing the flow.
Slowing the flow rate may also be
achieved by moving up stream and
activating upstream water controls and
shutting off other sources.
Oil-water separation is affected by a
multitude of factors such as: flow
rates, retention time, the difference in
surface tensions, under-currents, viscosity, specific gravity, solubility, etc.
To illustrate potential retention times
for oil-water separation to occur, the
following information is based on the
treatment of 2,000 gallon sized batch
loads of oily water discharged into a 3
ft. deep horizontal open-top settling
tank. After 10 to 20 minutes the majority
of the oil reached the surface,
formed an oil slick and was cleaned
off. After an additional three hours, a
substantial film of oil was evident and
was removed. Then, after 24 hours of
separation, there was a visible sheen
present on the water.
Making a seal at the rocky shoreline.
The dispersion of oil can result in a
widespread, thin oil slick or sheen on
the water. Time, money and effort are
wasted on oil slicks and sheens that are
not concentrated to maximize the
effectiveness of skimmers, sorbents
and vacuum trucks during the cleanup.
Sweeps and sorbent booms may be
used effectively as a mechanical means
to concentrate oil. Use the wind and
current as natural forces to concentrate
contaminants.
The force of a wind or breeze may
cause booms, equipment and the oil to
move out of their ideal position.
Sorbent booms in calm water may be
affected by a light breeze, causing the
overlapped sections of the booms to
separate. They may be tie-wrapped to
maintain their seal. Light weight sorbent
booms affected by a strong wind
may move too quickly across the surface
of the water, and allow the oil to
escape. Therefore, the booms may
have to be pulled tight and anchored to
limit their movement. This will cause
the booms to loose their flexibility and
may affect their ability to ride the
waves.
Effective response involves the following:
Response Objectives - Slow, divert,
or contain the spill.
Slow the Flow - make or find slow
conditions.
Retention Time - allow enough time
for oil to surface.
Retention Area - allow enough distance
for oil to surface inside the containment
area.
Continuous Freeboard - from
anchor point to anchor point to prevent
spill over.
Shoreline Seals - must be maintained
to prevent leakage.
Variable Water Levels - maintain
seals during rising or falling water levels.
Concentrate Product - use current,
wind and mechanical means to concentrate.
Recovery - use ‘high air-flow vacuum
systems’, sorbents to minimize
water content.
Monitor Conditions - anticipate
changes and adjust to new circumstances.
The most important factors for controlling
an oil spill are the flow rates
and the retention time. Finding or
making ideal flow rates for oil to
remain on the surface of the water and
provide enough retention time and area
for spills to reach the surface of the
water are the most important factors in
gaining control of a spill to open water.
Boom selection is the next critical
factor. Permanent, temporary, or sorbent
booms all have their positive and
negative traits, ranging from being
deployed in fixed positions for long
periods of time to immediate first
response applications. The features
that all booms must have is that they
must be a floating barrier that maintains
‘continuous freeboard’ on top of
the water to prevent splashover and
‘draft’, or a ‘skirt with ballast’ to provide
stability and prevent oil from
escaping underneath.
Deploying booms may be a science
but controlling the spill is an art.
By Cliff Holland, President of Spill
Management Inc.
Contact, e-mail: spillman@on.aibn.com.
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