Millions of tons of oil are produced in the world every year and over half of it is transported to users by means of marine routes. Based on statistics, a best estimate of oil spill is more than 3 million tons per year. Oil spills cause disastrous impacts on the environment, ecology and socio-economic activities. The right decision has to be made in the event of an oil spill to facilitate prompt action, considering the priorities of protection, to prevent environmental damages.
What is an oil spill?
An oil spillis a release of a liquid petroleum hydrocarbon into the environment due to human activity, and is a form of pollution. The term often refers to marine oil spills, where oil is released into the ocean or coastal waters. Oil spills include releases of crude oil from tankers, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, and heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.
Spills may take months or even years to clean up (like that of the Ogoni Land, in River State, Nigeria, which the United Nations report has revealed it will take about 30years to clean up). The UN had conducted a 14-month study of the effects of 50 years of oil drilling and transportation in the region and concluded that the situation is much worse than originally believed. The clean-up effort is expected to surpass that which followed the Gulf of Mexico spill last year with officials estimating recovery could take 25-30 years.
Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved.
The key to effectively combating spills is careful selection and proper use of the equipment and materials best suited to the type of oil and the conditions at the spill site. Most spill response equipment and materials are greatly affected by such factors as conditions at sea, water currents, and wind. Damage to spill-contaminated shorelines and dangers to other threatened areas can be reduced by timely and proper use of containment and recovery equipment.
Oil Spill Control Technologies
A number of advanced response mechanisms are available for controlling oil spills and minimizing their impacts on human health and the environment.
They are Chemical and Biological methods, Mechanical containment, amongst other physical methods.
Mechanical containment or recoveryis the primary line of defense against oil spills in the advanced world. It includes a variety of booms, barriers and skimmers, as well as natural and synthetic sorbents materials. Mechanical containment is used to capture and store the spilled oil until it can be properly disposed.
Chemical and Biological Methods: This method involves the use of dispersing agents and gelling agents. They are most useful in helping to keep oil from reaching the shorelines and other sensitive habitats. Biological agents have the potential to assist recovery in sensitive areas such as shorelines. Chemical and biological methods can be used in conjunction with mechanical means for containing and cleaning up oil spills.
Dispersing Agents: Dispersing agents, also called dispersants, are chemicals that contain surfactants and/or solvent compounds that act to break petroleum oil into small droplets. These droplets disperse into the water column where they are subjected to natural processes such as waves and currents that help to break them further.
Gelling Agents: They are also known as solidifiers. They are chemicals that react with oil to form rubber-like solids. For treating larger spills, these chemicals are applied to the oil, and then mixed in by the force of high pressure water streams. And with small spills, these can be applied by hand and left to mix on their own. In both cases, the gelled oil is removed from the water using nets, suction equipment or skimmers, and is sometimes reused after being mixed with fuel oil.