Research on the control and recovery of oil by use of surface active chemicals and in situ generation of polyurethane foam is discussed. Both laboratory experiments and full-scale field tests demonstrating the efficiency of the system are reviewed in depth. Total system capability utilizing highly portable chemicals and highly mobile sorbent spreading machinery and oil sorbent pick-up nets are evaluated as a function of oil spill size and weather conditions. Data on toxicity of the chemical agent to marine organisms are presented.
It is concluded that a surface active chemical oil spill control system is a feasible technique for controlling and recovering oil spilled on the ocean over a broad spectrum of weather conditions. It is further concluded that the chemicals utilized are harmless to the ecology.
A recent analysis1 of past major oil spills (38 spills examined during the period 1956 through 1969) has revealed that about 75% of the spills were associated with vessels, that a median spill was about 250,000 barrels of oil, that 80% of the spills examined were crude oil, and that about 50% of the spills occurred farther than one mile from shore. The study further showed that the effective wave height at the time of the spill, where data were available, was in excess of nine feet for over 50% of the incidents and over three feet for 90% of the incidents.
Oil spill containment and recovery has been achieved with only marginal success under severe weather conditions in the past. It is generally accepted now that existing mechanical booms are limited in their effectiveness to wave heights under four feet and current velocities under one knot. In addition severe wave and wind action has generally resulted in mechanical failure of booms. In those instances where booms were effective in containing oil, oil recovery tools have not been effective where any significant wave action was present.
The objective of the research and system development reported herein has been to evolve a system for oil slick control and oil recovery that would be largely independent of the weather limitations inherent in mechanical containment devices and in most existing oil recovery devices. The constraints placed upon the system are that it be effective under severe weather conditions and that it be highly mobile, preferably air transportable. The system that has evolved and which is reviewed in this report consists of:
Oil slick control by means of surface active chemical agents which possess spreading force greater than that of most oils. The surface - chemical agent prevents the spreading of oil on water and in most cases causes an existing oil slick to contract to occupy a smaller area of water surface.
Generation and spreading of an open cell, flexible polyurethane foam at the site, of the spill.
