Oil spills are dangerous because they affect marine ecosystems and unnecessarily endanger the existence of marine life. As oil exploration from offshore resources has become mandatory. And oil spills occur accidentally, it has become important to use different methods to handle oil spills.
Petroleum is one of the most common pollutants in the ocean. Approximately 3 million tons of oil pollute the oceans every year. However, oil spills vary in severity and damage. This may be due to differences in oil type, oil spill location, and prevailing weather conditions. Furthermore, the spread and behaviour of oil spills in the ocean. Are determined by a variety of chemical, physical, and biological processes.
Oil Spills
However, oil spills are nevertheless a serious problem as they can cause significant damage to ecosystems. The impacts extend far beyond the oil spill site. With negative impacts on coastlines and terrestrial wildlife thousands of metres from the oil spill site. Oil is less dense than water, so if it leaks or spills. It will float on the surface of the water (saltwater or freshwater). This makes cleaning up any oil spills much easier.
You can imagine how difficult it would be to repair a leak if oil was denser than water. And therefore formed a layer on the ocean floor rather than on the surface. A number of large-scale oil spills have occurred in recent years. Including the Exxon Valdez in 1989, the Prestige in a 2002, and the Deepwater Horizon in 2010.
As long as ships are at sea, oil spills will continue to be a pressing an problem and source of pollution. Most of the world’s petroleum products are manufactured and the production of petroleum from offshore sources continues to increase. However, oil spills almost always occur by accident, making it increasingly important to use various cleanup methods to counter the threats they may pose to marine ecosystems.
Three Common Methods Employed In The Cleanup Of Oil Spills Are
A variety of methods can be used to clean up oil spills. Some important and commonly used methods can be described as follows.
Use of Oil Booms
The use of oil booms is a simple and common method for controlling oil spills. A device called a containment barrier acts like a fence to prevent the oil from further spreading or drifting away. The boom floats on the water and consists of three parts.
- The “freeboard” is the part that extends above the water to absorb oil and prevent it from splashing onto the water.
- “Skirts” are placed below the water surface to force oil under the boom and prevent it from leaking.
- A type of cable or chain that connects parts to strengthen and stabilize the boom. The boom connections are placed around the oil leak area until it is sealed and contained.
Using Skimmers
Once the oil has been contained using an oil boom, a skimmer or oil scoop can be used on a boat to remove the contaminants from the water’s surface. Skimmers are machines specifically designed to suck the oil from the water’s surface like a vacuum cleaner. These are used to physically separate the oil from the water so it can be captured and processed for reuse.
Use of adsorbents
Adsorbents are materials that draw up liquids by absorption (drawing them through their pores) or adsorption (forming a layer on their surface). Both properties make the cleaning process much easier. Hay, peat moss, straw, or vermiculite are commonly used as oil sorbents.
More detailed methods
On-site combustion
This is a method in which oil floating on the surface is ignited and burned. This on-site oil combustion can effectively remove oil spills by up to 98%, which is better than most other methods.
According to Obi et al. (2008): “The minimum concentration (thickness) of sludge on the water surface for which the effectiveness of in situ combustion can be measured is 3 mm because it is difficult (or almost impossible).
Use of Dispersants
If an oil spill cannot be contained using a barrier, the only option left is to accelerate the breakdown of the oil. Dispersants, such as Corexit 9500, are chemicals that are sprayed onto spill sites using aircraft or boats to help the natural breakdown of petroleum components.
Allows oil and water to chemically bond by increasing the surface area of each molecule. This prevents the mud from moving across the water’s surface and allows it to be more easily broken down by microorganisms.
Hot Water and Pressure Washing
This process is primarily used in situations where the oil cannot be accessed by mechanical removal methods such as the use of booms or skimmers. It is generally used to remove trapped and weathered oil from locations that are not accessible by machinery.
Use a water heater to heat water to approximately 170°C and spray manually using a high-pressure wand or nozzle. This washes the oil to the surface of the water, where it can be recovered using skimmers or sorbents.
Use of manual labour
As the name suggests, this method requires hand tools and manual labour to remove contaminants. This involves cleaning surface oils and oily deposits using hand tools such as hands, rakes, and shovels and removing them from the shore by placing them in special containers.
Mechanical devices may be used to provide additional assistance or to reach inaccessible areas.
Bioremediation
Bioremediation refers to the use of specific microorganisms to remove toxic or harmful substances. For example, various fungi, bacteria, archaea, and algae break down petroleum products by metabolizing them and breaking them down into simpler, non-toxic molecules (primarily fatty acids and carbon dioxide). In some cases, we may also add reagents or fertilizers to the area.
These phosphorus and nitrogen-based fertilizers provide sufficient nutrients for microorganisms to grow and multiply rapidly.
This procedure is not typically used when oil spills occur in deep water but is implemented gradually as the oil approaches shore.
Chemical Stabilization of Oil Using Elastomers
Immediately after an oil spill, the immediate challenge is to prevent the oil from spreading and contaminating adjacent areas. Although mechanical methods such as the use of oil booms are effective in containing oil, there are certain limitations to their use.
Experts have recently been using compounds such as ‘elastor,’ which is essentially polyisobutylene (PIB) in the form of a white powder, to contain oil spills. This compound gels or solidifies oil on the surface of the water, preventing it from spreading or leaking. In addition, gelatin can be easily recovered, making work efficiency extremely high.
Natural reply
The easiest way to approach oil spill cleanup is to take advantage of the vagaries of nature, such as the sun, wind, weather, tides, and naturally occurring microorganisms. This is used when the coast is too remote or inaccessible, or when the environmental impact of cleaning up the spill may far outweigh the benefits. Due to the constancy of these elements, oils generally evaporate or are broken down into simpler components.
