Cleaning Oil Spills

1. Introduction

Recently, I have become very aware of human misuse of our earth’s environment. I think humans have not been very responsible and nice to our planet. We are polluting the land, air and water at a scary rate. One of the major causes of water pollution is oil spills. There are many oil spills around the world and each spill kills thousands of birds, aquatic and other forms of life. Oil spills are much more common than what I thought when I started this project. In Table 1, I summarize some of the oil spills during the past two decades.

Table 1: Some examples of oil spills

Date Place Estimated amount of oil spilled in water (million gallons)

March 24, 1989 Valdez, Alaska, USA 10

June 8, 1990 Off Galveston, Texas, USA

5.1

January 23-27, 1991 Southern Kuwait 520

April 11, 1991 Genoa, Italy 42

May 28, 1991 Angola 70

March 2, 1992 Fergana Valley, Uzbekistan

88

November 13, 2002 Spain 20

August- September, 2005

New Orleans, Louisiana 7

December 7, 2007 South Korea 2.8

Oil spills affect our planet’s ecosystems and the damage may be

irreversible. For example, some species of animals have still not recovered from the famous Exxon Valdez oil spill of 1989. Animals such as, the Killer Whale, the Harbor Seal, the Common Loon, Cormorant, etc. have still not recovered in the Prince William Sound in Alaska (AK). Although, animals such as the Bald Eagle and River Otter have managed to recover in the Prince William Sound, AK. The Valdez spill impacted

about 1,300 miles. This is more than the driving distance from Raleigh to Chicago, Illinois. It took about 10,000 workers, 1,000 boats and 100 airplanes, the U.S. Navy, the Army, and the Air Force to clean up the spill. The cost for Exxon to clean the mess was about $2.1 billion. The amount of oil spilled in this accident was about 10 million gallons. Note that the Valdez spill was not even among the top 10 worst spills! Just imagine how much damage the top 10 did.

2. How to clean the oil spills?

As mentioned above, oil spills can be very bad for our planet and our

economy. So it is important to avoid them in the first place. But when the spills occur it is important to clean them quickly and efficiently before they spread too far into the lakes, rivers, oceans and other bodies of water.

People have used many methods to clean oil spills. Booms are one

method to clean spills. Booms are floating barriers that round up the oil and lift oil off the water. Skimmers are machines that skim the oil from the top of water. Sorbents are sponges that soak up the oil. There are many other methods of cleaning oil spills. For more details on this subject, one may go to http://en.wikipedia.org/wiki/Oil_spill#Methods_of_cleaning.

One of my goals for this project was to find a material that would

absorb oil without absorbing water. I knew that Styrofoam is used as a packing material when shipping objects. This I assume is because it does not absorb water. So in this experiment I wanted to see if Styrofoam can be used for absorbing oil from a bowl containing water and oil.

Hypothesis: Styrofoam absorbs oil without absorbing water.

3. Material and Methods

Materials

• A large sheet of one inch thick Styrofoam. • Ruler. • Knife.

• Water. • Lawn mower motor oil. • Measuring cup. • Fifteen 6” diameter “Heafty soak proof impermeable” party bowls. • Three 18” long aluminum trays. • Clock.

Methodology

First I placed 5 party bowls in each aluminum tray. I put these bowls

in aluminum trays to avoid any spills on the carpet during the experiment. Two trays were labeled as control groups (Control-I, Control-II) and the third tray was the Experiment group.

Each bowl in the Control-I got 1 ounce of lawn mower oil per bowl,

whereas each bowl in Control-II got 7 ounces of tap water. The bowls in the Experiment group got 7 ounces of tap water and 1 ounce of lawn mower oil each.

I placed two blocks of Styrofoam, a 3”x3”x1” block and a 3”x 2”x1”

block in each bowl of the Experiment group tray and in each bowl of the Control-II tray. I didn’t place any Styrofoam blocks in Control-I tray bowls. See the Photo (A) below.

Photo A: The Experiment, Control-I, and Control-II groups.

Why control groups?

The purpose of Control-I tray was to estimate how much oil evaporated and/or was absorbed by the party bowl. Control-II tray was to estimate how much water was absorbed by Styrofoam blocks, and/or the party bowl and/or evaporated.

Why five bowls per group?

I used five bowls in each group because I did not expect to see the same result from each bowl at the end of the experiment because variability in my measurements. So I planned on taking the average (mean) of the results from the five bowls.

Room temperature

I performed this experiment in the basement of our house where we keep a constant temperature of 68o F.

4. Results

After forty-eight hours I decided to stop the experiment and see

how much oil was absorbed by the Styrofoam blocks in the Experiment group. Visually I could tell that a lot of oil that was floating in each bowl at the beginning of the experiment was absorbed by the Styrofoam blocks. They turned green. See Photo B.

Photo B: The five bowls in the experiment group and the Styrofoam blocks which turned green after absorbing oil.

Now I wanted to estimate the amount of oil that was absorbed by the Styrofoam blocks. This is where the two control groups played an important role.

From each of the ten bowls I carefully removed the two Styrofoam

blocks and placed them in an empty aluminum tray. I then emptied the liquid from each bowl into a measuring cup to measure the volume of the liquid in each bowl after 48 hours. The difference between the volumes at the beginning of the experiment and at the end of the experiment gave me the change in volume. As I expected the results from bowls within each group varied.

Table 2: Experiment group

Bowl Beginning Volume (Ozs) (X)

End Volume (Ozs) (Y)

Difference in Volume (Ozs) (X-Y)

1 8 7.125 0.875

2 8 7.250 0.750

3 8 7.500 0.500

4 8 7.000 1.000

5 8 7.000 1.000

The mean change in volume per bowl in the Experiment group = 0.825

Ozs. This number represents the mean combined loss of water and oil in 48 hours per bowl in the Experiment group. To estimate the amount of oil absorbed by the Styrofoam, I made use of the data from Control-I and Control-II.

Table 3: Control-I Group

Bowl Beginning Volume (Ozs) (X)

End Volume (Ozs) (Y)

Difference in Volume (Ozs) (X-Y)

1 1 0.9 0.1

2 1 1.0 0.0

3 1 1.0 0.0

4 1 1.0 0.0

5 1 0.9 0.1

The mean change in volume of oil per bowl in 48 hours for Control-I group = 0.04 Ozs. This number is not very accurate because my measuring cup was not very precise. I made sure I emptied all the oil into the measuring cup, but it was difficult to be perfect. Some very tiny amount of the oil was stuck to the bowl. I approximated the numbers to the nearest number on the measuring cup.

Table 4: Control-II Group

Bowl Beginning Volume (Ozs) (X)

End Volume (Ozs) (Y)

Difference in Volume (Ozs) (X-Y)

1 7 6.500 0.500

2 7 6.500 0.500

3 7 6.750 0.250

4 7 6.875 0.125

5 7 6.875 0.125

The mean change in volume of water per bowl in Control-II group

during 48 hours = 0.300 Ozs. This tells me that some amount of water is lost during 48 hours. This could be either due to Styrofoam absorbing the water, the bowl absorbing the water, and/or the water evaporated.

So, using all the above information, I estimate that the mean amount

of oil absorbed by Styrofoam block in the Experiment group = 0.825 – 0.300 – 0.040 = 0.485 Ozs. Since I started with 1 Oz of oil per bowl in the Experiment group,

therefore an average of 48.5% of oil was absorbed by the Styrofoam per bowl in 48 hours.

5. Limitations and Conclusions

Although I tried to be very careful in measuring the amount of liquid in each bowl, I may have made measurement errors. However, these errors may have occurred equally among the experiment and the control groups. So, they probably canceled out when subtracted the volumes in the above equation. So I think my estimate of the mean amount of oil

absorbed by Styrofoam is not likely to be affected by the measurement error.

From this experiment I learnt that materials such as the Styrofoam could be useful for cleaning oil spills. However I do not know why it works. I am sure there are better ways of cleaning oil spills without losing much water while cleaning. Perhaps in Middle or in High School I will learn about these things in a Chemistry class. I can’t wait to know why some materials absorb oil, while some do not absorb oil!

References: http://library.thinkquest.org/CR0215471/oil_spills.htm http://envirowonk.com/content/view/68/1/ http://en.wikipedia.org/wiki/Oil_spill#Methods_of_cleaning