Cleaning oil spills with bacteria has over time proven to be very effective in the remediation of oil spills. In this article, we discuss how cleaning oil spills with bacteria works.
The Deepwater Horizon incident in 2010 was a natural laboratory for us. It provided a situation that gave researchers from the University of Rochester the ability to study a system that they would not have been given funding to study.
They were able to measure the total mass of hydrocarbons, oil and gas, that was respired in the deep waters of the Gulf of Mexico and how that changed with time.
And that gives us an estimate of the rates of bulk oil and gas biodegradation. The research indicated that approximately 200,000 tons of oil and gas hydrocarbons have been removed by bacteria by September 2010 and that’s 2-3 months after the beginning of the disaster in 2010.
The deep waters of the Gulf of Mexico started to see a sharp increase in the rates of total oil and gas consumption. By 4 months into the disaster, those rates had passed their peak and were already starting to decline, as they became oil and gas limited.
They basically ate themselves out of house and home in the deep waters of the Gulf of Mexico.
Quantifying the rates of consumption by bacteria gives us some of the fundamental knowledge that’s able to translate what we have learned from the deepwater horizon disaster, potentially then to other disasters that might occur, to others oil spills at other areas of the planet.
We are looking at some of the fundamental capacities of cleaning oil spills with bacteria taking into consideration released oil and released natural gas.
And this gives us an idea of the amount of time that it would take, in certain areas of the world’s ocean, to remove any released hydrocarbons.
Interesting enough, the researchers of the University of Rochester noticed that when our rates of consumption of oil and gas increased most dramatically, it correlated with the time period where they are most aggressively injecting dispersant at the wellhead.
Now while there is much more research to be done to quantify the effectiveness and appropriateness of using dispersant in a natural ecosystem, at least to a first approximation, our results indicate that there is a correlation between the rates of biodegradation of chemicals, of oil and gas in the deep waters of the Gulf of Mexico, with the addition of dispersants.
The Exxon Valdez catastrophe occurred in 1989 after the tanker hit the Bligh Reef which is located in Northern Prince Willam Sound. This accident resulted in the tanker dumping 20% of its Prudhoe Bay Oil, 42 million litres, into the sea off the coast of Alaska.
This enormous amount of oil spread along the coast, contaminating more than 1900km of shoreline. This had a horrific effect on the natural habitat involved and resulted in the death of numerous animals.
The first stage of cleanup following the Exxon Valdez spill was the use of in-situ burning and a fire-resistant boom. This method, however, was quickly abandoned due to rough weather.
Following the attempt to burn the oil, mechanical methods were tried with the use of a skimmer and boom. This method was also unsuccessful due to the nature of the oil which was very dense and easily clogged the skimmers. The density of the oil also created problems and difficulties in transferring the collected oil.
As well as using mechanical methods, chemical dispersants were also used for cleanup. Like the previously attempted methods, dispersants were also unsuccessful. This controversial method failed due to the lack of waves needed to provide proper mixing of the chemicals with the sea.
With little luck resulting from the cleanup efforts applied, researchers from the EPA felt this situation was an ideal scenario to try bioremediation.
Although there had been the very little experience at this time with bioremediation, experts decided that “the Alaska oil spill situation should be treated as a laboratory to increase the nation’s knowledge and readiness for action in future oil spills” and the use of fertilisers should also be utilised.
It was known that there were indigenous hydrocarbon-degrading microorganisms present in Prince William Sound, and after the oil spill, it was found that there was a 10,000 fond increase in the number of these bacteria in the areas that were affected by the spill.
The use of bioremediation was proven to be effective in the Exxon Valdez spill, and within 10 to 14 days after the application of nutrients there was a noticeable difference in the reduction of oil on the sites which had biostimulation, compared to this were not treated.
This showed that using bioremediation not only worked at cleaning up the oil, but it also worked very quickly. With the success of bioremediation after the first summer of its use, the EPA then supported further use of bioremediation on the contaminated beaches and after more research, the EPA declared it a safe method for cleanup for marine oil spills.
So, if bacteria is that important, what are bacteria?
Bacteria also called prokaryotes are microscopic single-celled organisms that lack a nucleus and other membrane-bound organelles most bacteria have the same major parts a protective cell wall, a cell membrane and a strand of DNA many bacteria also have flagella whip-like structures that help them move and all bacteria reproduce by binary fission.
They grow until they split into two identical cells bacteria are very diverse. They can adapt to live in every type of environment on earth including areas of high heat, extreme cold, high acid or high salt content.
They are around the rod or spiral-shaped some are easily wiped out by medicines while some resist them. Of the three large groups or domains that biologists use to classify living organisms bacteria make up two of them Archaebacteria and Eubacteria
Archae or ancient bacteria have unique genes that enable them to get energy from unusual sources such as ammonia methane and hydrogen gas most bacteria however fall into the new bacterial domain while some bacteria can make you sick most sort of extremely important functions for example bacteria that live in your intestine help you digest food special bacteria called cyanobacteria make huge amounts of oxygen through photosynthesis for us to breathe.
Humans even use bacteria for everyday purposes. Bacteria help us make foods like yoghurt and cheese and some bacteria even play a crucial role in producing medicine. 90% of the cells that make the human body are actually bacteria cells and they are an essential part of what you.
Can You Clean Oil Spills with Bacteria?
Yes, you can clean oil spills with bacteria. By cleaning oil spills with bacteria, 80% of the oil spill can be remediated.
Which Bacteria is used to Remove Oil Spills?
Some of the bacteria which can be used for cleaning oil spills with bacteria also known as oil-degrading bacteria include:
- Alcanivorax borkumensis
- Bacillus subtilis
- micro bacterium
- Psedomonas aeruginosa
- Pseudomonas Putida
- Pseudomonas stutzeri
You can’t say these are the complete list of bacteria that can be used for cleaning oil spills (oil-eating bacteria) because bacteria evolve every day and we discover more and more bacteria that are capable of degrading oil.
Some of them have plasmids that help in their oil resistance, they also produce lots of surfactants called biosurfactants which would aid in the removal of oil from the water surfaces.
The main nutrients are added to microbes or bacteria to increase their ability to degrade oil include carbon, nitrogen, phosphorus, oxygen, and water.
For example, for one gram of hydrocarbon oil spill to be degraded, it would require 15mg of nitrogen and 30 mg of phosphorus, and water-soluble nutrient products are mainly used and they include:
potassium nitrate, sodium nitrate, ammonium nitrate, and dipotassium hydrogen phosphate promote the growth of the indigenous microorganisms which are capable of degrading oil.
When fertiliser is added to an oil spill environment, the following things should be checked:
- Rate of release
- Washout effect: this refers to tide that carries water out to sea and takes some nutrients with it.
- Type of nutrients.
Cleaning Oil Spills with Bacteria – How This Works
Since the process of naturally breaking down oil takes a long time, varying from weeks to years, humans had to find a solution to get rid of the huge oil leaks in the world’s oceans more efficiently and faster. Many of the solutions humans have figured out are not environmentally friendly while others are.
The use of biological agents which involves the cleaning of oil spills with bacteria is an environmentally safe option to aid the ocean and reduce pollution caused by oil leakage. Cleaning oil spills with bacteria can help keep wildlife sustainable.
This is because when an oil spill occurs next to wildlife, the safest and least damaging method to clean the water would be using biological agents and this is a relatively natural method.
Bacteria are introduced to the spill where it starts a process called biodegradation or bioremediation and fertilising agents that encourage the bacteria to grow are also added.
After it is added, the bacteria then starts to break down the oil into natural compounds that can be absorbed into the ground.
That basically means that the compound oil split up and formed into a chemical substance produced by a living organism and unlike oil, this naturally produced substance can be absorbed by the environment. This removes the oil and keeps wildlife pure from damaging liquids like oil leaks.
Advantages of Biological Agents
- It is a natural method of accelerating the biodegradation of oil without damaging the surrounding environment.
- Once the fitting agent is found, applying the agents to the oil spill can be very cost-effective in comparison to other methods.
- Biological agents don’t affect the growth of surrounding wildlife, but only deal with the oil and breaking down of them.
Disadvantages of Biological Agents
- You cannot control biological agents and what crops they manage. They can target other pests than the one initially targeted scientists.
- The process of finding the proper biological agents and creating a system can be very costly.
- Although they accelerate the biodegradation process, they can take many years to fully decompose the oil.
Regardless of all the other methods like we have a physical method of skimming, booms, in-situ burning, spraying, etc. But all these are methods which can be dealt with when it comes to small areas but what if it is being spread to a large area and when you have to deal with a large quantity of oil spill.
So, in such cases, bioremediation which is cleaning oil spills with bacteria plays a very important role. Bioremediation is the use of bacteria, fungi or bacteria to decompose the pollutants into simpler compounds.
As a result of bioremediation, we expect that the microbes will utilise these pollutants and convert them into carbon dioxide which is the simplest form of carbon and other compounds, as well as water, will be released.
And so, the prime goal is to create an optimal environment for the bacteria to degrade the pollutants and bioremediation is a very cost-effective alternative but, it’s a slow process and compared to the other methods it takes more time for the bioremediation to be done.
The results of it would be satisfied after the period of time and another advantage is that the bacteria can destroy the toxic hydrocarbon compounds and they don’t transfer them to another area that is, the bacteria itself will grow and will degrade the hydrocarbon at the in-situ condition itself.
How can you Enhance Cleaning Oil Spills with Bacteria?
Bioremediation which is cleaning oil spills with bacteria can be enhanced by making the environment favourable for the organism’s growth. It can be in different ways. We have :
- Addition of oxygen: This can be done by bio-venting and bio-sparging.
- Nutrient Addition: This is done through the addition of nutrients to the environment also known as bio-stimulation. Here the organisms are stimulated and are capable of utilising the hydrocarbon. The bacteria will be promoted to grow
- Using Alternative Electron Acceptors: This is the addition of electron acceptors to promote the growth and degradation
- Addition of Surfactants: Surfactants are substances that help the oil to become soluble in water. It can be utilised by the bacteria in a better manner.
- Addition of Bacteria: Also known as bio-augmentation, this is the addition of more bacteria to the oil spill to speed up the process of cleaning oil spills with bacteria. For cleaning oil spills with bacteria, it’s best to apply the bacteria at the spot of the oil spill so the process of bio-augmentation does happen.
Bio-Augmentation: This is the addition of bacteria and other microbes to supplement the current population to degrade oil and other hydrocarbons. It’s good to keep in mind that whenever an oil spill happens, the more chances it is to occur in a place where oil is previously handled.
For example, if you have a rig, oil is been handled over there and in such cases, naturally, there would be lots of hydrocarbons degrading organisms in that particular environment but, to enhance the remediation might be,
when an oil spill happens, we can utilise bacteria and other microbes which are capable of degrading oil spills and inject them into the oil spill environment and enable the bacteria to grow.
They are about 70 general microbes, microorganisms and bacteria that are known to degrade hydrocarbons.
So, the best bacteria which are capable of degrading oil should be injected into the oil spill environment in a prepared consortium which is a mixture of microbes or microorganisms or bacteria which are grown and could be of different nature.
The degradation of oil will only occur when the other conditions are met, for example, available nutrients and proper environment in temperature and all these conditions should be maintained so the process of bio-augmentation will become effective to remove hydrocarbons from oil.