10 Methods for Oil Spill Cleanup at Sea

Oil spills are hazardous as the marine ecosystem is affected, and the marine life-forms existence gets unnecessarily threatened.

Since oil exploration from oceanic resources has become a must, and oil spills occur accidentally, it becomes important to employ various oil spill cleanup methods.

Oil is one of the most abundant pollutants in the oceans. About 3 million metric tons of oil contaminates the oceans annually. However, oil spills vary in severity and the extent of damage they cause.

This can be attributed to variations in the oil type, the location of the spill, and the weather conditions present. In addition, the spread and behaviour of spilt oil in the seas is governed by various chemical, physical and biological processes.

But irrespective of these, oil spills are a serious concern as they can inflict a lot of damage to the ecosystem.

The effects are experienced not only in the area of the spill but also expand over vast regions to negatively impact shorelines and terrestrial wildlife thousands of metres away from the site of the spill.

Methods for Oil Spill Cleanup at Sea

Since oil density is lesser than water, it floats on the water surface when it leaks or spills (saltwater or freshwater). It is for this reason that it is much easier to clean up an oil spill.

It is easy to imagine the difficulty in cleaning up a spill if oil was denser than water, and as a result, formed a layer along the bottom of the seas instead of the surface!

In recent years, many major oil spills have taken place– the Exxon Valdez in 1989, the Prestige in 2002, and the Deepwater Horizon in 2010.

Oil spills will continue to be a pressing problem and source of pollution as long as ships move most of the petroleum products around the world, and exploration of oil from oceanic resources is steadily on the rise.

Nevertheless, oil spills mostly occur accidentally, and thus it becomes increasingly important to employ various cleanup methods for tacking the menace they could pose to the marine ecosystem.

Types Of Oil Spills Clean-Up Methods

Different methodologies can be adopted to clean up oil spills.

Some of the few important and commonly used methods can be explained as follows:

oil spill boom
oil spill boom – representation image

1. Using Oil Booms

The use of oil booms is a straightforward and popular method of controlling oil spills. Equipment called containment booms acts like a fence to prevent the oil from further spreading or floating away. Booms float on the water surface and have three parts –

• A ‘freeboard’ is the part that rises above the water surface, containing the oil and preventing it from splashing over the top
• A ‘skirt’ is placed below the surface and keeps the oil from being squeezed under the booms and escaping
• A kind of cable or chain that connects the parts to strengthen and stabilize the boom.
Connected sections of the boom are placed around the oil spill area until it is surrounded and contained.

Additional Information:

→ This method is effective only when the oil is in one spot.
→ It works when the spill is accessible within a few hours of taking place; otherwise, the area of the spill becomes too large to manage
→ It cannot be successfully employed under rough sea waves, high wind velocities or fluctuating tides.

Related Read: Fighting Oil Spill on Ship

2. Using Skimmers

Once the oil has been confined by using oil booms, skimmers or oil scoops can be deployed onto boats to remove the contaminants from the water surface. Skimmers are machines specially designed to suck up the oil from the water surface like a vacuum cleaner. They are used to physically separate the oil from the water to be collected and processed for re-use.

Additional Information:

  • Skimmers can be used to recover most of the spilt oil effectively, so it is economically viable.
  • The presence of debris poses a major roadblock to this technique, as skimmers can get clogged easily.

3. Using Sorbents

Sorbents are materials that soak up liquids by either absorption (pulling in through pores) or adsorption (forming a layer on the surface). Both these properties make the process of clean-up much easier. Materials commonly used as oil sorbents are hay, peat moss, straw or vermiculite.

Additional Information:

  • The oil can be recovered, and this prevents wastage and further pollution.
  • After the absorption, the sorbent materials must be effectively retrieved. This is a difficult task and may prove to be worse if ignored.
  • Sorbents, after absorption, become heavier (3 to 15 times their weight), and as a result, they may sink, making them difficult to retrieve and pose a risk to aquatic life in the sea bottom.
  • They are most effective in small spills or to manage the leftover traces of a larger spill.

4. Burning In-situ

In this method, the oil floating on the surface is ignited to burn it off. This in-situ burning of oil can effectively remove up to 98% of an oil spill, which is more than most other methods.

According to Obi et al. (2008), “The minimum concentration (thickness) of the slick on the water surface for any measurable effectiveness of in-situ burning is 3mm. This is because it would be tough (and even nearly impossible) to ignite a layer that is not thick enough.

Additional Information:

  • The toxic fumes released from the burning can cause significant damage to the environment and marine life.
  • The procedure works on relatively fresh spills before the oil spreads to a larger area and decreases in thickness.

Related Read: The Gulf of Mexico Oil Spill: The Complete Story of DeepwaterHorizon

5. Using Dispersants

When the spilt oil cannot be contained by using booms, the only option left is to accelerate the disintegration of oil. Dispersal agents, such as Corexit 9500, are chemicals that are sprayed upon the spill with the help of aircraft and boats, which aid the natural breakdown of oil components.

They allow the oil to chemically bond with water by increasing the surface area of each molecule. This ensures that the slick does not travel over the water’s surface and is easier to degrade by microbes.

Additional Information:

  • It can effectively be used for spills over large areas.
  • The use of dispersants can create tarballs. As the oil combines with water, it also gets mixed with sand and debris present in the water. This results in the formation of large tarballs floating on the water’s surface, which often finds their way to the shores.
  • The toxicity of dispersants can affect marine organisms, especially the non-mobile ones such as corals and seagrass.

Related Read: Different Types of Dispersants Used in an Oil Spill

6. Hot Water and High-Pressure Washing

This procedure is mainly used in situations where the oil is inaccessible to mechanical removal methods such as using booms and skimmers. It is used to dislodge the trapped and weathered oil from locations that are generally inaccessible to machinery.

Water heaters are used to heat water to around 170°C, then sprayed by hand with high-pressure wands or nozzles. The oil is thus flushed to the water surface, which can be collected with skimmers or sorbents.

Additional Information:

  • The released oil must be immediately and adequately recovered to prevent any further contamination.
  • Organisms falling in the direct spray zone have a high chance of adversely affecting the hot water.

Related Read: What is Ship Oil Pollution Emergency Plan (SOPEP)?

7. Using Manual Labour

As the name suggests, the method requires hand-held tools and manual labour to clean up the contaminants. It involves using manual means like hands, rakes, shovels etc., to clean the surface oil and oily debris and place them in special containers to be removed from the shoreline.

Sometimes, mechanized equipment may be employed for providing any additional help and reach out to any inaccessible areas.

Additional Information:

  • This method is applicable only for cleaning up the slick shorelines.
  • The process is more economically viable, as unskilled workers with minimal training can be employed for the process.
  • Apart from being labour intensive, this process is also time-consuming.
  • The use of heavy machinery can inflict damage upon shorelines, so they should be avoided as much as possible.

8. Bioremediation

Bioremediation refers to the use of specific microorganisms to remove any toxic or harmful substances. For example, various bacteria, fungi, archaea, and algae degrade petroleum products by metabolizing and breaking them into simpler and non-toxic molecules (mostly fatty acids and carbon dioxide). Sometimes, reagents and fertilizers may be added to the area.

These phosphorus-based and nitrogen-based fertilizers provide adequate nutrients for the microbes to grow and multiply quickly.

This process is generally not used when the spill has happened in the deep seas and is gradually implemented once the oil approaches the shoreline.

Additional Information:

  • It is a time taking procedure and may even take years, so quicker solutions like using booms and skimmers or sorbents may be used if any urgent action is required.
  • The fertilizers have an equally high chance of aiding the growth of unwanted algae, which consume much of the available oxygen and cut off sunlight from going to the deeper water levels. This can negatively impact marine life and prove to be counter-productive.

Related Read: What is An Oil Spill Kit?

9. Chemical Stabilisation of oil by Elastomizers

Right after an oil spill, the immediate concern is to prevent the oil from spreading and contaminating the adjacent areas. While mechanical methods like using oil booms effectively contain the oil, they have certain limitations to their use.

Experts have recently been using compounds like ‘Elastol’, which is basically poly iso-butylene (PIB) in a white powdered form, to confine oil spills. The compound gelatinizes or solidifies the oil on the water surface, thus preventing it from spreading or escaping. In addition, the gelatin is easy to retrieve, and this makes the process highly efficient.

Additional Information:

  • It is a quick action method, with typical reaction times of 15-40 minutes.
  • While PIB is non-toxic and commonly found in foodstuffs, the gelatin may risk entangling or suffocating the aquatic animals.

10. Natural Recovery

The simplest method of dealing with the oil spill cleanup operation is to use the vagaries of nature like the sun, the wind, the weather, tides, or naturally occurring microbes. It is used in certain cases when the shoreline is too remote or inaccessible, or the environmental impact of cleaning up a spill could potentially far outweigh the benefits.

Due to the constancy of these elements, the oil generally evaporates or is broken down into simpler components.

Additional Information:

  • It is one of the most cost-effective methods.
  • It is a highly time consuming and unreliable process and thus needs constant and close monitoring. It should not be confused with ‘sitting down and doing nothing.

A pivotal factor in cleaning up an oil spill is the location where it has happened. Most oil spills take place far out in the sea, so they are generally left to decompose in the environment naturally. However, as they get closer to the shores, we gradually begin to treat them.

The treatments follow a general rule: (All distances measured from the shoreline)

  • 200 nautical miles and beyond – No treatment is used unless the case is very severe.
  • Between 20 and 200 nautical miles, booms and skimmers may be used.
  • Between 20 and 10 nautical miles, dispersants are used.
  • For areas very close to the shoreline, biological agents are used.

These are only general rules and can be altered based on the type of oil that has been spilt and the prevailing weather conditions. No two oil spill cases are the same, so each one is evaluated individually based on its own merit.

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Disclaimer: The authors’ views expressed in this article do not necessarily reflect the views of Marine Insight. Data and charts, if used in the article, have been sourced from available information and have not been authenticated by any statutory authority. The author and Marine Insight do not claim it to be accurate nor accept any responsibility. The views constitute only the opinions and do not constitute any guidelines or recommendations on any course of action to be followed by the reader.

The article or images cannot be reproduced, copied, shared or used in any form without the permission of the author and Marine Insight. 

43 Comments

  1. Thank u so much for these tips on oil spill management. Please be sending me key oil spill updates for my perusal and understanding.
    Regards

  2. i sincerely appreciate these information, my knowledge of SPCC is broadened

  3. Great article! I glad to know about this information that you mentioned above.It is useful information to me which is informative.I am waiting to get more information from your site.Thanks for providing such information to all….

  4. All problems in the world whereher air pollution, water pollution or climate chabges caused by man.
    These nine steps can reduce oil pollution in ther water if we follow.
    Thank you for recommendation

  5. Natural recovery seems the safest and most caring of the marine ecosystem despite the fact that it might take a while. However, I also think Elastomers is a quick solution and somewhat harmful but can decently limit the oil spill.

  6. I live on the Gulf of Mexico. The DWH Disaster of 2010 is STILL causing harm. Even with books, skimmers, sorbents, burning, manual labor and a controversial dispersant both aerial and deepwater injection, the cleanup was not even 15% recovered. I believe BP has paid out $42 billion so far.
    Also dispersants which grab light oil sink it below the surface.
    Since the US FINES PER GALLON, o corps love dispersants (below surface) since it’s impossible to accurately assess the spill.
    Corexit 9527 is banned in over 30 nation’s, EPA tried to keep Corexit out but BP kept getting ’emergency use” permits.

    And in the Gulf, every oil spill response facility today still supplies one dispersant, Corrxit. It has killed deep reefs, killed oyster beds and diminished catches that sustained us for 1000s of years of fishing, shrimping.
    In truth, none of these 10 methods is much more than theatrics to reassure govts, people, media….. and oil profits are so huge, BP STILL made billions even WITH the “SPILL”. …y’all make it sound like you knocked over a glass of tea NOT 200 million gallons and 2 million gallons of poison on us, our homes and our waters

  7. What are some affective methods used to clean up the pollution from oil spills in the ocean and how do these methods work?

    – Using oil booms
    – Very simple and popular methods of controlling oil spills.
    – Float on the water surface.
    – Have three parts (freeboard, skirt and cable or chain)
    – Only effective when oil is in one spot.
    – Can’t be successfully employed under rough sea waves, high wind velocities or fluctuating tides.
    – Using skimmers
    – Used after oil has been confined by oil booms.
    – Skimmers can be deployed onto boats.
    – They remove contaminants from the water surface.
    – Machines specially designed to suck up the oil from the water.
    – Oil can then be collected and processed for re-use.
    – Economically viable.
    – If there is debris in the water skimmers can get clogged easily.
    – Using sorbents
    – Materials that soak up liquids by absorption or adsorption.
    – Absorption is the process of pulling in through pores,
    – Adsorption is the process of forming a layer on the surface.
    – Makes the process of cleaning oil spills much easier,
    – Oil can be recovered

  8. What are some affective methods used to clean up the pollution from oil spills in the ocean and how do these methods work?

    – Using oil booms and skimmers
    – Very simple and popular methods of controlling oil spills.
    – Float on the water surface.
    – Have three parts (freeboard, skirt and cable or chain)
    – Only effective when oil is in one spot.
    – Can’t be successfully employed under rough sea waves, high wind velocities or fluctuating tides.
    – Used after oil has been confined by oil booms.
    – Skimmers can be deployed onto boats.
    – They remove contaminants from the water surface.
    – Machines specially designed to suck up the oil from the water.
    – Oil can then be collected and processed for re-use.
    – Economically viable.
    – If there is debris in the water skimmers can get clogged easily.
    – The boom moves into the skimmer with oil in it and wraps around it.
    – Using sorbents
    – Materials that soak up liquids by absorption or adsorption.
    – Absorption is the process of pulling in through pores.
    – Adsorption is the process of forming a layer on the surface.
    – Makes the process of cleaning oil spills much easier.
    – Oil can be recovered, this prevents wastage and further pollution.
    – Difficult to do.
    – May end up worse if this isn’t done.
    – Sorbents after absorption become up to 15 times as heavy as they were originally.
    – This makes them sink and hard to retrieve.
    – Aquatic life threatened because they have all the collected oil in them.
    – Most effective in small spills or to manage the leftover traces of a larger spill.
    – Using elastomizers

  9. Anish are you able to provide us with the name of the author? This is the only page I’ve seen that has all types of methods to clean up an oil spill and that has been currently dated. I too have to cite my work with an author. So this would be very helpful. Thank you.

  10. The Exxon Valdez oil spill happened on March 4, in 1989 in Prince William Sound, Alaska. The spill was caused by the tanker hitting a reef and tearing open the hull of the ship resulting in about 11 million gallons of oil being spilled into the pristine waters of the sound. The spill killed an estimated 250,000 sea birds, 3,000 otters, 300 seals, 250 bald eagles and 22 killer whales.

  11. This work is really a wow. i am currently work on a project. i want to seek permission to used a part of it for the write up. how do i get permission

  12. The information provided here was useful,very clear and easy to understand. Thank you so much.

  13. Hey i am doing a class project so i was wondering if you could just u know tell me wat is the most popular and efective way out of theese 10 ways to cleanup oil spills?????????? I hope u answer

  14. Kindly inform what are the precautions to be taken when an bunkering ship transferring ATF/LHHSD and Petrol to direct pipe line to store in a tanker built away about 500 meters.

  15. This was very informative and most appreciated. During the gulf spill an absorbent was to be used (MOPN), but was cancelled by the Coast Guard for some unspecified reason. Could someone find the reason for its not being tried. It still seems like a logical product. It has such high a high absorbent, light weight to volumn and doesn’t sink in water.

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