804 OIL SPILLAGE INTO WATER—TREATMENT
easily deployed lightweight booms are desirable. However,
these desired properties are not necessarily consistent with
making booms stronger and more capable of withstanding
severe sea conditions.
These are the criteria and mechanism of operation of oil
spill booms. It is beyond the scope of this chapter to present
the many commercial and changing commercial products.
In the world Catalog of Oil Spill Response Products, booms
have been divided into three categories based on maximum
operating signifi cant wave height (Hs). Table 1 shows the
ranges of freeboard and draft corresponding to the expected
maximum waves. A boom size can thus be selected based on
the expected environment.
In the World Catalog of Oil Spill Response Products,
booms have been divided into three categories based on
maximum operating signifi cant wave height (Hs). Table 1
shows the ranges of freeboard and draft corresponding to the
expected maximum waves. A boom size can thus be selected
based on the expected environment.Boom Selection Matrix The selection of a boom depends on
how rapidly it is needed and how readily it can be utilized.
Deployment speed and ease relate to the number of people,
the amount of time, and any special equipment (Winches,
etc.—even wrenches) necessary to move the required amount
of boom from storage to the launch site, to deploy it, and to
position it around the spill. For example, self-infl atable booms
can be deployed very rapidly either from reels or bundles.
Experience has shown, however, that this rapid response boom
should be replaced by a more rugged boom if extended deploy-
ment is required. Thus, deployment ease must often be traded
off against ruggedness and durability.
The matrix shown in Table 2 can be used to select the
optimum boom for a specifi c application since it indicates:- Generic types of boom that are most suitable in a
given environment - Selected booms that have the most needed perfor-
mance characteristics - Choices with the most desirable convenience
features.
Excess or reserve buoyancy is the surplus of fl otation over
boom weight as deployed, and is a measure of resistance
to boom submergence. Wave response is a measure of con-
formance to the water surface and is usually improved byincreasing boom water-plane area and fl exibility. Other char-
acteristics should be evident from the headings.
To use the matrix correctly, follow these steps:- Identify the most probable environmental condi-
tions in which the boom will be used. Note those
types of booms with an acceptable rating (1 or 2). - Identify the most needed performance charac-
teristics for the intended application. From the
booms chosen above, select the ones that have an
acceptable rating (1 or 2) in the most important
performance characteristics. - Identify the most desirable convenience features.
With booms from steps 1 and 2 above, select the
boom with the best rating in the convenience fea-
tures of interest.
These data (Table 1 and 2) were extracted and used with the
permission of EXXON from a very informative OIL SPILL
RESPONSE FIELD MANUAL by Exxon Production
Research Company published in 1992.Recovery of the Spill by Sorbing Agents A most direct
manner of physically removing the spilled oil is by use
of sorbents. These materials are buoyant, and preferen-
tially wetted by and adsorb oil. In essence, they permit
this sorbed oil to be physically “picked up” from the water.
In addition to making the collection of oil an easier task,
the oil is prevented from spreading and remains as a more
congealed mass.
Materials that have been found useful for this service vary
from simple, naturally occurring materials such as straw, saw-
dust, and peat to synthetic agents, such as polyurethane foam
and polystyrene powder. The oil pickup capability varies
greatly. For example, values of oil pickup, i.e., weight of oil
sorbed per weight of adsorption material, have been reported
by Struzeski and Dewling^7 for straw as 3 to 5, although higher
values have been reported. Polyurethane foam, by comparison,
is capable of oil pick up values of 80. A complete investiga-
tion of sorbents for oil spill removal has been published by
Schatzberg and Nagy.^8 Of interest is the variation in the oil
pickup capability of a given sorbent based on the type of
spilled oil. For example, in Schatzberg’s controlled tests, oil
pickup by straw was 6.4 for heavy crude oil and 2.4 for light
crude oil. For urea formaldehyde foam, however, oil pickup
was 52.4 for heavy crude and 50.3 for light crude. Also someTABLE 1
Boom ClassificationEnvironmentHs Maximum Freeboard Draftft meters inches centimeters inches centimetersCalm Water 1 0.3 4–10 10–25 6–12 15–30
Harbor 3 0.9 10–18 25–46 12–24 30–61
Offshore 6 1.8 18 46 24 61C015_002_r03.indd 804C015_002_r03.indd 804 11/18/2005 10:56:38 AM11/18/2005 10:56:38 AM