Efficient methods of breaking down crude oil in seawater

Introduction: (Initial Observation)

Every year variety of accidents to oil tanker ships and other oil related facilities in the sea contaminates seawater with billions of gallons of crude oil. Each crude oil spill accident destroys many marine life and makes the shore line unusable for human and other animals. There are known mechanical methods for controlling the oil spill and recovery of the oil, however a large amount of oil will remain and must be treated to reduce it’s harm.

In this project you research chemical methods of treating what is left from an oil spill after mechanical cleanup. The purpose of such treatment is to reduce or stop the harmful effects of oil or destroy the oil by converting it to other safe forms.

Information Gathering:

Find out about oil spills and oil spill treatment methods. Read books, magazines or ask professionals who might know in order to learn about the effect or area of study. Keep track of where you got your information from.

Oil is the most common pollutant in the oceans. More than 3 million metric tons of oil contaminate the sea every year.

Oil spills occur in oceans, lakes, and rivers all over the world. Some of these spills are large and very damaging to nature while some are small and occur regularly.

When an oil spill occurs, the oil floats on top of the water. This is because the oil is less dense than the water. Density is a measure of how much mass an object contains for a specific volume.

The extent of damage a spill does to the environment is related to the oil type, size of the spill, weather conditions, location of the spill, and the timing of the spill.

Winds, tides, and waves will all have an effect on where the oil goes and how much damage it does.

The oil from a spill can effect the marine environment by:

• coating the substrate and organisms living on nearby shorelines with oil.
• evaporating into the atmosphere to become an aerosol that is transported by the wind.
• breaking into smaller particles in the water that are ingested by zooplankton and small fishes and enters the food chain.
• coating the fur and feathers of mammals and birds, destroying their insulating ability reducing buoyancy, and harming the animals when the oil is ingested as they clean themselves. Animals die from exposure, drowning, suffocation, or from ingestion of oil.

The majority of oil pollution in the oceans comes from land. Runoff and waste from cities, industry, and rivers carries oil into the ocean. Ships cause about a third of the oil pollution in the oceans when they wash out their tanks or dump their bilge water.

Oil spills account for less than 15% of the total oil in the oceans but are probably the most obvious form of oil pollution. The damage caused by oil spills is certainly seen right away.

We’ve all seen images of the water’s surface and shoreline covered with oil and dying animals and plants. Oil spills will continue to be problem and source of pollution as long as ships and barges move most of our petroleum products around the world.

When oil leaks or spills into water it floats on the surface of both freshwater and saltwater. Oil floats because it is less dense than water. Density is a property of every liquid, solid, and gas. Density tells how much mass is in a specific volume (mass divided by the volume) of a material.

You may have seen this written as an equation: Density = mass / volume

It may help to think of density as the relative heaviness of a material or how compact or crowded the molecules are in the material. Denser materials have larger number values than less dense materials. For example, oil has a density of 0.85 g/cm3 and seawater has a density of 1.02 g/cm 3 .

When these two liquids are mixed together, the denser seawater forms a layer underneath the less dense oil.

It’s much easier to clean-up an oil spill because of oil’s lower density. You can imagine how difficult it would be to clean-up a spill if oil was denser than water and formed a layer along the bottom instead of the surface. We humans have come up with some pretty creative ways to clean-up spilled oil and we’ve described some of the major methods below.

Mechanical

Americans primarily use mechanical methods to clean-up oil spills. Listed here are the three categories of mechanical tools used to contain and recovery spilled oil.

4. Booms– It’s easier to clean-up oil if it’s all in one spot, so equipment called containment booms act like a fence to keep the oil from spreading or floating away. Booms float on the surface and have three parts: a ‘freeboard’ or part that rises above the water surface and contains the oil and prevents it from splashing over the top, a ‘skirt’ that rides below the surface and prevents the oil from being pushed under the booms and escaping, and some kind of cable or chain that connects, strengthens, and stabilizes the boom. Connected sections of boom are placed around the oil spill until it is totally surrounded and contained.

5. Skimmers– Once you’ve contained the oil, you need to remove it from the water surface. Skimmers are machines that suck the oil up like a vacuum cleaner, blot the oil from the surface with oil-attracting materials, or physically separate the oil from the water so that it spills over a dam into a tank. Much of the spilled oil can be recovered with skimmers. The recovered oil has to be stored somewhere though, so storage tanks or barges have to be brought to the spill to hold the collected oil. Skimmers get clogged easily and don’t work well on large oil spills or when the water is rough.

6. Sorbents– These are materials that soak up liquids by either absorption or adsorption. Oil will coat some materials by forming a liquid layer on their surface (adsorption). This property makes removing the oil from the water much easier. This is why hay is put on beaches near an oil spill or why materials like vermiculite are spread over spilled oil. One problem with using this method is that once the material is coated with oil, it may then be heavier than water. Then you have the problem of the oil-coated material sinking to the bottom where it could harm animals living there. Absorbent materials, very much like paper towels, are used to soak up oil from the water’s surface or even from rocks and animal life on shore that becomes coated with oil.

Chemical

Chemicals, such as detergents, break apart floating oil into small particles or drops so that the oil is no longer in a layer on the water’s surface. These chemicals break up a layer of oil into small droplets. These small droplets of oil then disperse or mix with the water. The problem with this method is that dispersants often harm marine life and the dispersed oil remains in the body of water where it is toxic to marine life.

Physical

7. Burning– Burning of oil can actually remove up to 98% of an oil spill. The spill must be a minimum of three millimeters thick and it must be relatively fresh for this method to work. There has been some success with this technique in Canada. The burning of oil during the Gulf War was found not as large a problem as first thought because the amount of pollution in the atmosphere did not reach the expected high levels. Field-testing is needed to check the feasibility of this technology.

Biological

1. Bioremediation– There are bacteria and fungi that naturally break down oil. This process is usually very slow- it would take years for oil to be removed by microorganisms. Adding either fertilizer or microorganisms to the water where the spill is located can speed up the breakdown process. The fertilizer gives the bacteria and fungi the nutrients they need to grow and reproduce quicker. Adding microorganisms increases the population that is available to degrade the oil. A drawback to adding fertilizers is that it also increases the growth of algae. When the large numbers of algae die they use up much of the oxygen so that there isn’t enough oxygen in the water for animals like fish.

Over time, a number of things can happen to oil that has been spilled. The oil may evaporate, reach the shore and cover beaches, remain suspended in the water for long periods, or sink into ocean sediments. The problem of cleaning up oil often becomes more difficult the longer the oil is in the water.

Oil spills can happen anywhere and anytime. The paragraph below tells about an oil spill that happened in New England when a tanker ran aground.

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Vocabulary

Pollutant: Any substance that contaminates or makes the environment impure. Pollutants are commonly man-made wastes.

Density: The mass or quantity of a substance per unit of volume (m/V). The relative heaviness of a material or how compact or crowded the molecules are in the material.

Absorption: The process of taking in another substance, in the same manner that a sponge would.

Adsorption: When a liquid or solid takes up a substance and holds it on its surface, so that the substance coats the molecules of the solid or liquid.

Dispersant: A chemical or material that when added to some other substance causes it to break apart and scatter about.

Bioremediation: Using natural biological processes to correct or counteract an environmental hazard or ecological disaster. An example of bioremediation is adding fertilizer or bacteria to the water to help clean-up an oil spill.

Ecosystem: An ecological unit of all the living organisms plus the nonliving, physical environment and how they function together.

Question/ Purpose:

What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.

Can detergents break down oil? How much detergent is needed to break down certain amount of oil and make it disappear? Is polluted water safe for marine animals and plants after being treated with a detergent?

The purpose of this project is to determine the effect of chemicals and detergents in reducing the concentration of oil in a polluted water.

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

The independent variable is the amount of detergent used to emulsify certain amount of oil.

The dependent variable is the rate of oil emulsification.

Controlled variables are temperature, type of detergent, amount of water, type and concentration of oil in water.

Hypothesis:

Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.

Detergent molecules can bind with oil and force oil to dissolve in water. If oil contains harmful material, it will remain harmful after being treated with detergents.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Following is a sample experiment to determine the effect of bacteria on oil degradation.

Experiment 1:

Introduction

Oil released into the environment has many harmful affects. The extent of the pollution can be enough to make a vast area uninhabitable for human and animals. Detergents are potentially able to dissolve (emulsify) the oil in water and make it disappear. Oil-detergent molecules dissolved in water can disperse, so eventually the concentration of oil-detergent may become so low that it will no longer be harmful to the environment.

Procedure:

1. Get a 2 liter container and add one liter fresh water to that. (you may repeat this experiment with salt water or sea water and compare the results. Some detergents can not dissolve in salt water, so they will have no effect on emulsifying the oil).
2. Add 5mL motor oil to the water. (You may use used motor oil or olive oil or any other type of oil that you can find at home. Crude oil is a mixture of many different oils and chemicals.)
3. Use a pipette or burette to add dish washing detergent one drop at a time. Record the number of drops and the number of milliliters of detergent that you use.
4. Add one drop detergent, slowly stir the solution for one minute. (Try not to agitate the water to prevent foam).
5. Continue this until all oil disappears. Record the number of drops and the number of milliliters of detergent used to disappear the oil.

Additional/ Optional steps:

6. Stop stirring for one hour. Part of oil may demulsify and rise to the water surface. Use any filter paper to absorb the oil on the top of the water, let it dry and if you have access to a high precision balance, weight the paper to determine the amount of oil demulsified. (you need to know the weight of paper before absorbing oil)

7. Calculate the percentage of the oil that formed a stable emulsion with detergent.

Discussion

How much detergent is needed for every gallon of oil to disappear?

Experiment 2:

Oil collection boat

A boat can be designed to continuously suck the oil from the surface of water, transfer it to a separation device on the boat where clear water can be discharged and collected oil can be burned. The heat generated from burning oil can be used to run the boat and produce electricity needed for operation of instruments on the boat. Components of an oil collection boat (You may call it a decontamination boat) are:

• Surface suction mechanism
• Oil/water separator
• Storage for collected oil
• Oil burning mechanism
• Boat navigation system that can be automated using Global Positioning System

Design and make a model of the decontamination boat using Styrofoam, wood or a combination of different material.

Perform experiments to show how oil and water separate because of their density and because most oils are hydrophobic.

Procedure:

Mix 100 mL vegetable oil with 400 mL water in a plastic one liter soda bottle.

Shake the bottle for one minute to mix water with oil as it happens by waves and pump in a decontamination boat.

Transfer the mixture to a 1000 mL measuring cylinder.

Make observation every minute and record the amount water at the bottom, and the amount of oil on the top in a table like this.

Oil water separation rate

Lapsed time from shaking	Oil layer (mL)	Water Layer (mL)
1 minute
2 minutes
3 minutes
…..
…..

Since you know you started with 100 mL oil, you can calculate the percent of oil recovered in a different table like this:

Lapsed time from shaking	Percent of oil moved to oil layer
1 minute
2 minutes
3 minutes
…..

You may use this table to draw a graph to show the rate of oil separation in time.

Materials and Equipment:

List of material can be extracted from the experiment design. Following is a partial list of material for the experiment number 1.

• one 2-liter beaker or jar
• one pipette or burette
• motor oil or any other oil
• liquid detergent
• filter paper (optional)
• High precision scale (optional)

Results of Experiment (Observation):

Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.

Calculations:

You may optionally calculate the percent of oil emulsified by the amount of detergent that you used. For example you may say that 0.23 gallon of certain detergent is able to emulsify one gallon of certain oil while 12% of oil will demulsify within one hour from the time you stop stirring.

Summary of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.

Conclusion:

Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.

If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.

References:

List of References

http://omp.gso.uri.edu/omp/default.html

http://omp.gso.uri.edu/doee/teacher/pdf/act13.pdf

http://www.epa.gov/superfund/programs/er/resource/underoil.pdf

http://www.humboldt.edu/~mwcc/index.shtml

http://www.capetownskies.com/1058/jun00.htm

http://resources.yesican.yorku.ca/trek/galapagos/oil7.html

http://www.epa.gov/oilspill/docs/pdfbook.htm

http://response.restoration.noaa.gov/kids/spills.html

http://www.cutter.com/osir/primer.htm

Related Experiment 1:

This experiment is designed to help you to understand the difficulties involving oil spill cleanups.* To perform this experiment you will need the following materials:

• one cake pan or similar container approximately 20 cm x 20 cm;
• 480 mL of clean pea-size gravel;
• 480 mL of water;
• 480 mL clear plastic cup;
• An eyedropper or plastic spoon;
• Three pipe cleaners;
• A piece of plastic wrap 10cm x 5 cm;
• Ten cotton balls (use real cotton);
• A piece of nylon stocking 10cm x 5 cm;
• 120 mL of wood chips;
• Four paper towels; and
• 30 mL of dark olive oil.

Advanced Preparation: This activity is designed for students to work in groups of three.

1. Wash the pea-size gravel
2. Place the 480 mL of pea-size gravel on one side of the cake pan/container, and pour all of the water on the other side. Make sure that most of the pea-size gravel remains on one side of the container. This material is to represent a river bank, a lake shore, or an ocean beach.

Procedure: Complete each of the following steps, and observe what happens.

1. For each experiment you will need a cake pan/container prepared as described above, a plastic cup, three pipe cleaners, an eyedropper/plastic spoon, ten cotton balls, a piece of nylon stocking, four paper towels, a piece of plastic wrap and wood chips.
2. Make an animal from the pipe cleaners and lay it on the gravel next to the water.
3. You are going to clean up an oil spill that occurred at a local river, lake or ocean beach (you decide). The gravel represents the bank, shore or beach of the water body you selected.
4. Pour 30 mL of olive oil on the water. Blow the oil toward the gravel to simulate water movement. You should then attempt to clean up the water, shore and animals using any of the materials provided. Test each material to clean carefully so you can determine which material works best. Place any oil and water you removed from the container in a plastic cup.

Interpretive Questions: As the groups of three perform the experiment ask them to observe what happens and answer the following questions. Afterwards, the groups of three can join together and discuss their discoveries.

1. Which cleanup material proved to be the best for cleaning up the water? Which material worked the best for cleaning up the “shoreline?”
2. Was there any difference in cleaning up the water when the conditions were calm and when the conditions were rough (blowing on the water)?
3. Is there any way that a spill can be contained in one area? How could contaminants spread from the area where the spill occurred?
4. How might people be exposed to contaminants? How might plants and animals be exposed to contaminants?
5. What would happen if the oil spill was not cleaned up?

Cleaning up an oil spill

1. Background

What does oil do in seawater?

Since oil floats in water, a body of crude oil spilt into the ocean will accumulate at the surface of the water. There it can be washed onto shore killing wildlife and upsetting fragile marine and coastal ecosystems causing serious damage.

2. Define ‘clean up’ and ‘successful clean up’

• ‘Clean up’ (in the case of an oil spill) means a complete cleansing of the water, so that that it is completely uncontaminated and back to its original state
• ‘Successful clean up’ refers to making the contaminated area appear clean, but in actual fact the water is still contaminated with pollutants not visible to us.

3. List and explain the methods you proposed to clean up the spill.

Three methods were proposed:

a. burning the oil off the top of the water by setting it alight after it had accumulated on the top.
b. drawing all the oil from the top of the water, filtering out the oil, and putting the clean water back into the ocean. This would contain the spilt oil allowing it to be re-used or recycled.
c. heating the seawater and the oil and see if the oil would evaporate. This seemed impossible because there is no way to heat the ocean to the size of the spill.

4. The method used.

We drew the oil from the top of the water, then filtered the oil from any seawater that was taken up with it. After the oil was filtered out the clean seawater was put back in the ‘ocean’ so that the oil could be re-used or recycled.

We used a beaker containing 150mL of seawater and 3 squirts of oil from the dropping pipette. We used a pipette to extract the oil off the top of the water where it had accumulated after time and filtered it into a second beaker through a funnel lined with filter paper (as shown in the diagram below).

1. Oil is extracted from the solution via a pipette
2. The oil is then filtered in a funnel lined with filter paper to separate any seawater from the extracted solution
3. Cleaned water

5. Describe the method you used to measure the effectiveness of your clean up operation.

The method we used to measure the effectiveness of the clean up was to see how much oil we ended up with after we filtered away the seawater. To start the experiment we put in approximately 3 squirts of the oil from a dropping pipette into the water. When it came time to see how much we had extracted from the seawater we looked to see if it was an equal amount to what we first put in.

6. Assess the effectiveness of the method that you chose.

We decided that our method produced a ‘successful clean up’ as it was impossible for us to totally remove all the oil from the seawater with the limited equipment and knowledge we had of the proper procedures. Most visible oil was gone. The only remnant of oil left was the smell still in the water.

What effect does crude oil have on wildlife?

Procedure:

1. Get 10 identical glass containers in five pairs and number them from 1A, 1B for the first pair, 2A and 2B for second pair, …5A and 5B for the last pair.
2. pore one liter clean water in each container.
3. Place two small goldfish in each container.
4. Add nothing to the first pair (1A and 1B), keep them as control.
5. Add one drop of motor oil to each of the containers 2A and 2B.
6. Add two drops of motor oil to each of the containers 3A and 3B.
7. Add three drops of motor oil to each of the containers 4A and 4B.
8. Add four drops of motor oil to each of the containers 5A and 5B.
9. Make observations every hour for the first 6 hours and every 12 hours after that for 3 days.
10. Record your observation time/ date and condition of fishes (number of sick or dead fishes) in a table.

Results:

• How long did it take for the first fish to be effected by oil contamination.
• Did oil contamination kill any of the fishes?
• What percentage of fishes died in the first 24 hours?
• does increase in the amount of contamination cause a higher death rate?

Related Links:

http://www.uaa.alaska.edu/enri/apex/