From Exxon Valdez in 1989, the Prestige in 2002, to the Deepwater Horizon in 2010, an oil spill is a nasty thorn in everyone’s side. Unfortunately it’s a present threat that accompanies any oil operation that takes place within or near a water surface (seas, oceans, rivers, etc.). What makes an oil spill terrible is that it creates a vicious web of interconnected hazards and causes tremendous damage to the ecosystem not only in the area of the spill, but it can expand over vast regions to affect coastlines and wildlife hundreds of miles away. Additionally, combating an oil spill is an immensely tedious task which involves a lot of continuous efforts since its effects last for extended periods of time.
That’s why when any form of oil spill occurs, it’s crucial to take the right steps to contain and clean it up, with immediate response being key.
Many different methods have been developed to safely contain an oil spill and prevent it from doing much harm, but they all fall into three main processes:
This is the most common oil spill cleanup method but its effectiveness depends primarily on how early the response was, with some consideration to weather or sea conditions. It involves two steps:
This is done using floating booms that prevent the spill from getting out of control. This is most effective when the response takes place within the first few hours of the spill, otherwise the area of the spill gets too large to contain.
Additionally, the floats are equipped with skirts that hang down below the booms to contain the oil and prevent it from escaping. However, if the waves are too high or winds are too strong, the booms become ineffective.
Once the booms are in place and the oil is contained, special boats with equipped skimmers called Vessels of Opportunity (VOO) are used to remove the oil off the surface of the water.
Apart from skimming however there are other solutions:
- Sorbents (sponge-like substances) that absorb the oil and pull it out of the water surface are sometimes used for larger oil slicks.
- In certain instances where the spill happens out at sea, in situ burning is an option (but a very controversial one). This involves burning the oil slick off the surface of the water. But the burn creates a highly toxic smoke, which is why this method cannot be used for spills that take place near a coast line.
When the oil spill containment becomes impossible, the best remaining choice is to speed up the natural breakdown of the oil components. One way of doing this is by using dispersal agents into the water. These are chemicals that are thrown into the water using air-crafts or boats that allow the oil to chemically bond with the water, preventing the slick from traveling over the water surface.
This method does however, has many significant drawbacks, a major one being the creation of tar balls. As the oil bonds with the water, it congeals around the sand and other particles in the area which result in large tar balls that float over the surface. These can be scooped up by skimmers, but usually find their way back to the shore.
This clearly makes dispersants not the ideal solution, for the following reasons:
This method also involves speeding up the breakdown of the oil in the water, but using biological agents which break down the oil into fatty acids and carbon dioxide. This process is usually used when the oil has reached the shore, but has recently been tested on river systems.
This involves using phosphorus and nitrogen based fertilizers to promote the growth of microorganisms that break down the oil.