Following the last blog post on introducing oil spills and the various aspects surrounding it like how it happens and response behaviors of companies, the next few posts will focus on clean up techniques.
If you haven't read the last post, check it out here before continuing with this one.
BIOREMEDIATION & DISPERSANTS
In producing oil, there are loads of things that can go wrong as with most facets of life. During the oil production process, whether it’s drilling, transporting or refining, there will be the unavoidable generation of large quantities of an oily and viscous residue called oily sludge, just like the inevitability of corruption in Africa.
In addition to that, there is a possibility of oil spills which as I explained in the last blog post, can pose a lot of problems. Bioremediation has emerged as one of the very viable ways to deal with oil spills and the toxicity of the hydrocarbons in the crude oil. The process isn’t usually the go-to option for most regulatory bodies or oil companies because stakeholders are less likely to try out something new unless they’ve seen positive results. The process also has a few limitations.
HOW IT WORKS……
The process of bioremediation works making use of the concepts of reduction and oxidation in chemistry. The reduction is basically gaining electrons to make an atom more stable and oxidation is losing an electron(s) to make an atom more stable. Lol, it's like having a toxic trait that limits you from being your best self, losing the trait allows you to live your best life (OXIDATION) and a person living in abject poverty who suddenly winning the lottery, with money added to their lives it solves all their immediate problems (reduction).
So, during the process of an oxidizing agent, oxygen is usually is added to stimulate the oxidation of a reduced chemical (pollutant), or a reducing agent usually an organic substrate is added to stimulate the reduction of the oxidized pollutant. In both processes, however, a buffer (an aqueous solution consisting of a mixture of a weak acid and its conjugate base) is usually added in order to provide an environment in which the microorganisms can thrive to attain the best results. Kind of how Pogba would be more productive if he went to Real Madrid because he’d be surrounded by the right players under the right conditions to perform better, unfortunately, he finds himself at Banter FC. BUT WE MOVE!!!
In dealing with oil spills, aerobic bioremediation is usually made use of because it leads to the formation of water. The formula is:
O2 + 4e- + 4H+ = 2H2O
Oxygen is the most commonly used oxidizing agent because it also serves as a catalyst (a substance that speeds up a reaction) in the process. The effectiveness of the whole process, however, depends heavily on the type of oil that was spilled. Hydrocarbons with a low molecular weight will most often degrade at a high rate. The higher the molecular weight, the less likely it is for the oil to degrade. This happens because for bioremediation to keep on working, there needs to be a steady supply of nitrogen and phosphorus, which do not occur naturally in hydrocarbons. These are usually added to the area to be treated in order to improve the effectiveness of the treatment. Adding nitrogen and phosphorus do pose a few problems, however, which include:
Since they will be added in the form of their respective salt solutions, there remains a high possibility for the salt to dissolve rapidly.
The utilization of bacteria that do not degrade oil in any way.
Increasing the concentration of nitrogen leads to more environmental damage.
There are experiments that have been done however that have proven that the use of hydrophobic nitrogen and phosphorus that have a low solubility in water can overcome these problems. These chemicals can be referred to as bioremediation accelerators because they promote the growth of biodegrading bacteria. They do this by bonding chemically and physically with the soluble and insoluble hydrocarbons. They also act as herding agents, restricting the floating oil to spread any further. It serves as a temporary boundary to restrict the flow.
DISPERSANTS
Dispersants are also used in bioremediation. These are chemicals that are also used to speed up the natural removal process. Dispersants are made up of chemicals and substances that are found in household products so there is very little risk of it damaging the environment or its inhabitants. A visual representation of how dispersants work would be, take for example a cackle of hyenas attempting to devour an elephant after a kill. It would take quite a bit of time to finish the meal. Now picture the elephant cut up into many parts and passed around to the hyenas, it would then take a shorter period for them to finish the meal. This is how dispersants work, they break up the oil slicks in order to speed up the natural removal process for biodegradation. For this reason, dispersants are amongst the most effective response tools in the event of an oil spill.
A few companies have come up with products that have proven to be very effective forms of biodegradation. One of these is PetroLuxus from Ascension Technologies who use Femto-scale technology which is just a fancy upgrade of nanotechnology.
As much as there are loads of advantages to using bioremediation to clean up oil spills, there are a few disadvantages to it that usually discourage oil companies to consider it for immediate response. They include:
Microorganisms cannot thrive in all environments and therefore makes the process of bioremediation nigh on impossible to work effectively.
Regulating environmental factors can be expensive and hard to maintain. Most factors are interdependent, and experiments carried out in the lab may be successful on a small scale but getting the same results on a large scale will be harder.
The process is slow.
Here is a video showing how bioremediation works. Click here.
In conclusion, even though bioremediation is not the immediate go-to response when an oil spill happens mostly because its still a relatively new mode of clean up and experiments are still being carried out to determine its effectiveness. It is a viable option though because the by-products are carbon dioxide and water which are in no way harmful to the environment. Ultimately I think more care needs to be exercised at offshore rigs and tankers transporting oil and measures need to be put in place to prevent the oil spills.
References
United States Environmental Protection Agency. A Citizen's Guide To Bioremediation.
Swaranjit Singh Cameotra, Pooja Singh., 2008. Bioremediation of oil sludge using crude oil surfuctants.
Ron, E.Z. & Rosenberg, E., 2011. Biosurfactants and oil bioremediation.
Boopathy, R., 2000. Review paper Factors limiting bioremediation technologies.
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