Even with the effort to avoid them, oil spills still occur to threaten sensitive environments. The use of super-tankers and off-shore drilling and remote terminals in geologically active areas serve to increase the damage when spills do occur. Massive oil spill disasters have been experienced in the last few years due to these activities.
Even with the heightened awareness leading to quick responses, prior art techniques available for controlling and removing oil slicks from surface waters and adjacent coastlines are unsatisfactory. Dispersants and detergents are taught to be effective in household cleaners for dispersing oil from surfaces in U.S. Pat. No. 4,992,213 in other environments. Various absorbent materials have been proposed to be applied to the slick to remove or sink the oil to the bottom of the body of water as described in U.S. Pat. Nos. 4,401,475, 4,492,001 and 3,800,950, for example. This treatment always involved the pickup of the absorbent and the oil, resulting in a double clean-up disposal.
As described in U.S. Pat. No. 4,492,001, the method involved in response system whereby absorbent materials are spread on a contaminated area, such as a beach, to absorb the spill, and then is sucked by a vacuum, either through the same nozzle or another nozzle, to a container wherein it is removed from the environment. While effective in some instances, it remains ineffective for the more difficult clean-up jobs relying upon the mechanical contact of absorbent materials with the contaminating spill. In U.S. Pat. No. 3,800,950, the removal of an oil slick is described wherein an open cell material such as polystyrene is broadcast upon an oil slick and scooped up by a modified scow. The patent describes the foaming of the polystyrene in the well known popcorn manner. This foam itself is broadcast on the surface to absorb the oil slick.
Another technique utilizes a treated silica which will act as a wick and permit burning of an oil slick, particularly on water. In situ burning of the spilled hydrocarbon has been an institutionally acceptable, but ineffective, solution in the arctic regions, but it is dangerous, especially in the presence of a natural gas leak. For these and other reasons, the hydrocarbon contaminations have been mainly controlled by very primitive methods such as by skimming with pumps, by manually collecting the oil with shovels and rakes, by washing rocky shorelines with high-pressure hot water hoses, and by coagulating the oil with straw which is then removed and burned. Attempts have been made to corral oil slicks with ultrasonic sound as described in U.S. Pat. No. 4,222,868, which also describes many other vain attempts.
Nowhere was the failure of these prior art techniques more evident than in the response to the 1990 Exxon Valdez spill off
the coast of Prince William Sound in Alaska. All then existing techniques of oil spill remediation were considered for the job and were either rejected or proved to be futile. Not only was there an absence of effective methods to remove the oil on an emergency response basis, but there was also no effective method for the ultimate clean-up of the spillage from the sea or the coast. The total damage may not be known for years, if ever.
Removal of an accidental oil spill from water surfaces or land areas has long been, and will continue to be, a serious problem associated with the production and transportation of oil, and is also a vital enterprise. Although various mechanical devices have been designed to remove oil spread on the surface water, the number of safe methods for removal of oil from land has been limited. Statistics show that only about 10% of the oil spilled is recovered using the best technology available. In such a situation, it is particularly important to preserve the ecological balance, so as not to destroy living organisms while cleaning oil contamination. Not only are crude oil and petroleum product spills a problem, the environment is also contaminated with many hydrocarbon based hazardous materials which were previously in wide use throughout the world, such as diesel fuels, creosote, dioxins, furans and polychlorinated phenols.
The relative importance of an efficient, cost-effective, and environmentally-sound process and equipment for removing and recovering spilled oil or removing oil from contaminated soils is nowhere more crucial than in the hostile environment of the polar regions where any activity is hampered by extreme temperatures which affect all fluids, including any materials used for cleanup as well as the spilled contaminant. Traditional beliefs about the fragility of the environment, substantial experience with the high-costs of commercial and industrial operations, variable as well as extreme weather conditions, and tenuous logistics place added emphasis on the need for processes and equipment that are efficient, relatively fast, and economically competitive. Until now, these have been missing.
Other recovery methods and equipment are disclosed in U.S. Pat. Nos. 5,076,919; 5,059,252; and 4,758,355, for example. Few problems have received the attention that hydrocarbon contamination has. Yet, the problem remains, but the practice of the instant invention serves to provide another tool to the continuing battle.