Download Environmental Biotechnology and Bioremediation

Environmental Biotechnology and Bioremediation.
Bioremediation
Bioremediation refers to any method that uses microbes (microorganisms)
to recycle organic materials and sequester inorganic ions.
"Remediate" means to solve a problem, and "bio-remediate" means to use
biological organisms to solve an environmental problem such as
contaminated soil or groundwater.
 Bioremediation is a relatively new way to cleanup toxic waste by
using bacteria that have been found in nature that will convert the
toxic substance to safe substances.
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In some cases, bacteria may be genetically engineered to destroy the
toxic waste.
Because the primary responsibility of microbes is to recycle organic
material, they must be present in sufficient quantities.
BioAugmentation is the addition of naturally occurring microbes to
sites. BioStimulation is the modification of sites to enhance the
growth of indigenous microbes already present.
Use of microbes for bioremediation is not limited to detoxification of
organic compounds.
In many cases, selected microbes can also reduce the toxic cations of
heavy metals (such as selenium) to the much less toxic and much less
soluble elemental form. Thus, bioremediation of surface water with
significant contamination by heavy metals can now be attempted.
The occurrence of major incidents (such as the Exxon Valdez oil spill,
the Union-Carbide (Dow) Bhopal (India) disaster, large-scale
contamination of the Rhine River, the progressive deterioration of the
aquatic habitats and conifer forests in the Northeastern US, Canada,
and parts of Europe, or the release of radioactive material in the
Chernobyl accident, etc.) and the subsequent massive publicity due to
the resulting environmental problems has highlighted the potential for
imminent and long-term disasters in the public's conscience.
Microorganisms have also been successfully applied during the
removal of the Exxon Valdez oil spill.
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A number of microorganisms can utilize oil as a source of food, and
many of them produce potent surface-active compounds that can
emulsify oil in water and facilitate the removal of the oil.
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In a non-polluted environment, bacteria, fungi, protists, and other
microorganisms are constantly at work breaking down organic matter.
What would occur if an organic pollutant such as oil contaminated
this environment? Some of the microorganisms would die, while
others capable of eating the organic pollution would survive.
Bioremediation works by providing these pollution-eating organisms
with fertilizer, oxygen, and other conditions that encourage their rapid
growth.
These organisms would then be able to break down the organic
pollutant at a correspondingly faster rate.
Bioremediation provides a technique for cleaning up pollution by
enhancing the same biodegradation processes that occur in nature.
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How Bioremediation works?
 Usually, the bacteria are sprayed onto toxic chemicals lying on the
ground (such as used to cleanup the oil spill of the Exxon Valdez in
Alaska), or the bacteria may be released into an aquifer via a well.
 The bacteria spread, and when they find the toxic waste they like to
eat, they break it down into non-toxic substances.
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As they eat, they also begin to reproduce and multiply in numbers.
The more bacteria there are, the faster the wastes are cleaned up.
Advantages of Bioremediation:
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It is a natural and safe process.
It is cost effective.
Relatively inexpensive.
No buildings need to be dug up and removed.
Works over large areas (especially above ground).
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This method is quick (above ground) or slower underground (where
the water moves more slowly).
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This method has been used effectively on oil spill cleanups in the
past.
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As long as there is toxic waste, the bacteria continue to feed on it.
Thus, they may eventually cleanup the entire site!
Disadvantages:
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Hard to control where the germs (bacteria) go.
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Some people are concerned about having lots of germs spread around.
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Some people are concerned that some of the germs may be able to kill
people or make them sick. In most cases, bacteria that eat toxic waste
are probably not able to make people sick.
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Many people around the world are concerned about the use of
something that is not natural, that has been genetically engineered as
many of the bacteria used for toxic cleanup have been!
Cost: $10 million/ about $200 extra/ year on tax bill.
Under careful controlled conditions, bioremediation can be a practical and
cost effective method to remove hydrocarbons from contaminated surfaces
and sub-surfaces.
Bioremediation Links:
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For more information on bioremediation, read about Decay and
Renewal.
 Voracious microbes clean up pollution at Hanford
 Bioremediation Links
 Today's growing bioremediation industry
 Good & bad information about bioremediation
 Bioremediation
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Conan the Bacterium
"Engineered bacterium eats toxic waste"
EPA’s Citizens Guide to Bioremediation
EPA’s Compost for Bioremediation booklet
Hazardous Waste Clean-up Information
Life in Extreme Environments
Natural and Accelerated Bioremediation Research
 Oil Spills (NOAA, Office of Response and Restoration)