Encyclopedia of Environmental Science and Engineering, Volume I and II

814 OIL SPILLAGE INTO WATER—TREATMENT

Therefore, in recent years, research has been directed at

eliminating the need for the tedious, time consuming

mixing process.

In essence, a “self-mix” dispersant formulation has been

developed that requires essentially no energy to be applied

to the oil-water interface in order to generate a dispersion

of fi ne oil droplets. This has greatly enhanced the scope

and potential of chemical dispersion particularly for large

spills. For example, since mixing is no longer needed, aerial

application alone would be feasible. Some aircraft uniquely

adapted for this service, such as the canadiar CL-215, carries

1500 gallons of dispersant and covers 3000 acres per hour

based on a 150 knot speed and treated swath width of 150

feet. Extensive use has already been made of commercial

DC-4’s and DC-6’s for this purpose. A very novel devel-

opment of a load on tank and spray system for even larger

aircraft is now in place.

The Mechanism of More Recently Developed Self-Mix

Dispersants

The mechanism of the self-mix chemical dispersants goes

beyond the simple thesis represented by Eq. (2). In an ideal

no-mixing system true spontaneous emulsifi cation (or “self-

mixing”) is postulated to occur in the following manner. The

chemical surfactant formulation is made compatible with the

bulk oil. However, when the oil phase comes into contact

with a water boundary rather than air, part of the surfactant

Sea Water

Oil Layer

Application

A)

B)

C)

Diffusion

Oil Associated With

Self-Mix Dispersant

Transported Into

Water Phase

As Fine Droplets

FIGURE 7 Mechanism of self-mix dispersion.

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