This document discusses bioremediation techniques for oil spill cleanup. It begins by defining bioremediation as using microorganisms like bacteria and fungi to break down pollutants like oil. Several methods are described to enhance bioremediation including adding nutrients, oxygen, or microbes. The Exxon Valdez oil spill is discussed as a case study where techniques like controlled burns, dispersants, and fertilizer-enhanced bioremediation were used. Overall, the document provides an overview of bioremediation and how it can be applied to effectively treat oil spills in the environment.

1. Bioremediation
of oil spills
Submitted by-
Anchal Garg
Environment Science
2016

2. Oil spills
• Oil spills occur frequently throughout the world. There
are both inland and oceanic spills.
• Oil spills require quick action so that they cause as
little damage as possible.
• According to the Environmental Protection Agency
(EPA), “oil releases threaten public health and safety by
contaminating drinking water, causing fire and
explosion hazards, diminishing air and water quality,
compromising agriculture, destroying recreational
areas, wasting nonrenewable resources, and costing
the economy millions of dollars” (2006).

3. Methods
• The methods chosen to clean up an oil spill are determined
based upon the type of oil spilled, the location and its
proximity to sensitive environments, and other
environmental factors.
 Mechanical methods- booms, skimmers, and truck
vacuums.
 Chemical methods- dispersants, surface washing agents,
and surface collecting agents.
 Biological methods -use of microbiological cultures,
enzyme additives, and nutrient additives to increase the
rate of biodegradation of the contaminants.
 Natural methods - another course of action. Simply allows
the area to recover naturally and is cheaper than any other
method.

4. Bioremediation
• The use of microorganisms, fungi or bacteria, to decompose
pollutants into simpler compounds is called bioremediation.
• Microbes breaking down different substances into water,
carbon dioxide, and other compounds .
• The prime goal of bioremediation is to create an optimal
environment for the microbes to degrade pollutants.
• Bioremediation is a cost effective alternative but is a very
slow process, sometimes taking weeks to months for results.
• An advantage of bioremediation is that the microbes are able
to completely destroy the toxic hydrocarbon compounds and
do not just transfer them to another area.

5. Enhancement of bioremediation
1. Addition of oxygen,
2. Nutrient addition (Bio stimulation),
3. Using alternative electron acceptor,
4. Addition of surfactants,
5. Addition of microorganisms (Bio
augmentation).

6. Bio augmentation
• addition of microbes to supplement the current population
to degrade oil and other hydrocarbons.
• This is usually not necessary, since these microbes are
present in nearly every location.
• In order to utilize microbes, it is first essential to find which
types of microbes are capable of degrading oil and
determine their nutrient and environmental requirements.
• There are 70 genera of microbes that are known to degrade
hydrocarbons.
• The degradation of oil will only occur if the other
requirements are met, such as available nutrients and the
proper environment temperature.

7.  Several genera of oil-
degrading bacteria :-
Flavobacterium and
Cytophoga sp.,
Pseudomonas sp.,
Xanthomonas sp.,
Alcaligenes sp., and
Arthrobacter sp.
 Bacteria :- strains of
Pseudomonas aeruginosa,
Pseudomonas stutzeri, and
Bacillus subtilis

8. Bio stimulation
• addition of nutrients to aid in the growth of the
indigenous microbe population.
• Major nutrients: carbon, nitrogen, phosphorous,
oxygen, and water.
• Main concerns are oxygen supply and temperature.
• Nutrients must be available and in contact with
microbes.
• 1 g hydrocarbon requires 150mg N and 30mg P.
• C:N:P = 100:5:1
• Commonly used water-soluble nutrient products
include mineral nutrient salts (e.g. KNO3, NaNO3,
NH4NO3, K2HPO4

9. • When a fertilizer is added to a contaminated
area, following things should be checked-
1) Rate of release
2) Washout effect- “Washout” refers to tide
that carries water out to sea and takes some
nutrients with it
3) Type of nutrients

10. Advantages
• Less expensive,
• Natural process,
• Not disruptive to
surrounding
ecosystems ,
• Does not require
moving oil to another
location,
• Continues to
improve conditions.
Disadvantages
• Bio-augmentation
not very effective,
• Success depends on
proper nutrients and
environmental
conditions,
• Takes time to
evaluate site,
• Takes time to see
results.

11. Exxon Valdez Oil Spill
• On March 24, 1989, the tanker Exxon Valdez
grounded on Bligh Reef in Alaska's Prince
William Sound, rupturing its hull and spilling
nearly 11 million gallons of crude oil into a
remote, scenic, and biologically productive
body of water.

12. Techniques used to remove or clean oil
i. Controlled burning,
ii. Chemical dispersants,
iii. high pressure/hot water washing,
iv. cold water washing,
v. fertilizer enhanced bioremediation,
vi. manual and mechanical removal of oil and
oil laden sediments.

13. Controlled Burns
• efficiently and rapidly reduce the volume of a
threatening oil slick.
• Concerns over atmospheric emissions

14. Chemical Dispersants
• Dispersants used to break up the oil and speed up
the natural biodegradation process. Example-
Xylan gums.
• similar to emulsifying agents.
• Dispersants are not appropriate for all oils and all
locations. If the oil is dispersed through the water
column it can affect marine organisms like corals
and sea grass.
• It can also affect organisms that are important in
the seafood industry.

15. Manual/mechanical cleaning
Generally, the strategy to cleaning up a spill
begins with containment booms and
skimming technologies.
 contain the oil spill with booms and then
collect the oil from the surface of the water by
using skimmer equipment.
 Large sponges called
sorbents can also be used
to absorb much of the oil.

16. References
• Bragg, J. R., Prince, R. C., Wilkinson, J. B. & Atlas, R. M.
Bioremediation for Shoreline Cleanup Following the 1989
Alaskan Oil Spill
• EPA Website. (2006) http://www.epa.gov/oilspill/index.htm
• Gordon, Ray. (1994) “Bioremediation and its Application to
Exxon Valdez Oil Spill in Alaska.”
• Michel, J., S. Christopherson, and F. Whipple. (1994)
Mechanical Protection Guidelines. Columbia, South
Carolina
• R.C. Prince, R.R. Lessard and J.R. Clark; 2003,
Bioremediation of marine oil spills; Oil & Gas Science and
Technology Vol. 58 (4), pp. 463-468

17. Thank you

18. Thank
you