Availability of Petroleum reserves only in few parts of the world and the demand across all parts of the world necessitate the movement of the oil cargo using marine transportation. Here comes the bad face associated with it called “Oil Spill”.
Introduction to Oil Spill
Oil Spill is the release of Liquid Petroleum substance into the environment mainly in marine area. Oil spill may also occur in land during transportation using cross country pipelines. Oil spill is characterized based on the following properties of the oil substance and the environment of the sea.
Density of the Oil – Most of the Petroleum compounds are lighter than water and hence they float on the water surface.
Viscosity of the Oil – It is the resistance to flow. If viscosity of the oil is high then it will offer more resistance to flow in the water surface and spread area may be less. Spread are also depends on Quantity of the spill and climatic conditions.
Volatility of the Oil – It is the tendency of the oil to evaporate. Normally smaller chain hydrocarbons will vaporize quickly.
Toxicity of the Oil – It refers to the poisonous ability of the oil to human and other living organisms.
Apart from the above said properties of oil Wave energy and Slope of the shoreline will also determine the movement of oil in the sea.
Few Notable Oil Spills include the following.
BP Oil Spill or Deep Water Horizon Oil Spill caused by well head blow out in the year 2010 near Gulf of Mexico, United States.
Cosco Busan Oil spill caused by collision of container because of thick fog in the year 2007 in San Francisco.
Montara Oil Spill caused by leak in well head platform in the year 2009 in Timor sea, Australia
Effects of Oil Spill
Oil Spill poses fire hazard. If the spilled oil is highly volatile it will vaporize easily and forms a hydrocarbon vapor cloud and it has got a fair possibility of explosion.
Based on the toxicity of the oil, it may cause irritation to eyes, respiratory system, fatigue, asphyxiation etc among human.
Oil goes into the feathers of birds and reduces the insulating ability and birds may die due to loss of body heat. Oil slick on the birds feather impairs the birds ability to fly and they die because of starvation of food. Ingestion of oil causes irritation in digestive tract and causes Kidney/ Liver damage among birds.
Oil spill causes damage to plant life, aquatic species, coral, rocks etc.
If the spilled oil reaches shore, it damages the beaches and causes land pollution. Oil seepage into the ground may contaminate the water bodies and ground water pollution.
Oil Spill Cleanup
Oil Spill Cleanup may take days to years based on the properties and quantity of the spilled oil.
Booms are deployed to fence the spread of oil spill. Normally boat is used to deploy the containment boom around the leaking ship. Containment Boom floats on the water surface, height above the water surface is called “Free board” and the height of the skirt which sinks below the water surface is called “Draft”. Watch this video to understand how the boom is deployed to contain oil spill.
Skimmers are floating devices employed to skim off oil from water surface. The skimmed oil is recovered, pumped and stored in the containers at shore or in the same oil tanker or in another oil tanker based on the quantity/spread/ distance from shore. This animation video helps to understand the operating basis of a floating drum oil skimmer.
For small oil spills these absorbent pads can be used. These absorbent pads are Oleophillic (absorbs only oil) and Hydrophobic (Repells water).
Oil Dispersants is used to break oil slick into small droplets as the small droplets can be easily biodegraded by microbes. Use of Oil dispersant involves a logical decision based on exposing coastal life to surface oil or exposing marine life to dispersed oil. Aircraft or boat is used to spray dispersant over oil spill.
It can be done in low wind to reduce the quantity of oil spill. It causes Air pollution and respiratory ailments. The limitations include ignition of the oil, hard to maintain the combustion of the slick, and emission of large quantities of smoke.
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