Use of microorganisms to degrade contaminants and alter environmental conditions.

2. 1. Introduction.
2. Types of bioremediation.
3. Microorganisms in Bioremediation.
4. Factors affecting Bioremediation.
5. Advantages and Disadvantages of
Bioremediation.
6. Summary.
7. Conclusion.
8. References.

3.  Bioremediation refers to the process of using
living microorganisms to remove the
environmental pollutants or prevent pollution.
 The removal of organic wastes by microbes for
environmental clean-up the essence of
bioremediation.
Bioremediation is a combination of two words “
bio” means living and “ remediate” means to solve
a problem or to bring the sites and affairs into the
original state.
Bioremediation technology using microorganisms
was reportedly invented by George M. Robinson

4. 1. In situ Bioremediation :
o In situ bioremediation means there is no need to
excavate or remove soils or water in order to
accomplish remediation.
o It is superior method to cleaning contaminated
environments since it is cheaper and uses harmless
microbial organisms to degrade the chemicals.
o It involves the supplying oxygen and nutrition by
circulating aqueous solution through naturally
occurring bacteria to degrade organic compounds.
o In situ bioremediation is applied to the degradation
of contaminants in saturated soils and ground water.

5. Types of In situ Bioremediation
There are two types of in situ bioremediation.
1. Intrinsic In situ Bioremediation : Conversion
of environmental pollutants into the harmless
forms through the innate capabilities of
naturally occurring microbial population is
called Intrinsic In situ Bioremediation.
2. Engineered In situ bioremediation : Its
accelerates the degradation process by
enhancing the physicochemical conditions to
encourage the growth of microorganisms.

6. Advantages of In situ Bioremediation:
Don’t require excavation of contaminated
soils. Less expensive, less chance of
contaminated other sites.
 Possible to treat a large volume of soil at
once.
Disadvantages of In situ Bioremediation:
 it is slow process and difficult to manage.
 Require uncompacted soil.

7. Ex situ Bioremediation
o Ex situ Bioremediation involves the removal of waste
water material and their collection at a place to
facilitate microbial degradation.
o The average time frame for ex situ Bioremediation is
60 – 90 days hence faster compared to In situ
Bioremediation.
o Better control area, depth, nutrients, oxygen,
moisture, temperature etc.
o On the basis of contaminated under treatment ex
situ bioremediation is classified into two types solid
phase system and slurry phase systems.

8. SOLID PHASE SYSTEM
Land farming : Land farming is a
simple technique in which
contaminated soil is excavated( dig
up) and spread over a prepared bed
and periodically tilled until pollutants
are degraded.
Composting : Involves the combining
contaminated soil with nonhazardous
organic amendants such as manure
and agricultural wastes.
Biopiles :
Typically used for treatment of surface
contamination with petroleum
hydrocarbons they are a refined
version of land farming that tend to
control physical losses of the
contaminants by leaching and
volatilization.

9. Slurry Phase system
o Slurry phase bioremediation is are relatively more rapid
process compared to the other treatment process.
o Contaminated soil is combined with water and other
additives in a large tank called a “Bioreactor “
o Nutrients and oxygen are added and conditions in the
bioreactor controlled to create the optimum
environment for the microorganisms to degrade the
contaminants.
o Slurry phase system include Bioreactors, Bioventing,
Biosparging and Bioagumentation.

10. Bioreactors :
• Soil and water pumped up from a
contaminated plume and processed
through an engineered containment
system.
• Degradation in a bioreactor is generally
greater than in situ because the contained
environment is more controllable and
predictable.
Bioventing :
• Bioventing employs low air flow rates.
• involves the amount of oxygen
necessary for the degradation and
nutrients through wells to contaminated
soil to stimulate the indigenous bacteria.

11. Biosparging : Involves the
injection of air under pressure
below the water table to
increase groundwater oxygen
concentrations and enhance the
rate of biological degradation of
contaminants by naturally
occurring bacteria.
Bioagumentation :
Bioremediation frequently
involves the adding microbes
and organisms to strengthen the
same in waste to allow them
take over and decontaminate
the area.

12. Living microorganisms are used in Bioremediation, to convert the
complex toxic compounds into harmless by products of cellular
metabolism such as CO2 and H2O. The successful use of
microorganisms in Bioremediation depends on the development
of a basic understanding of the genetics of a broad spectrum of
microorganisms and Biotechnological innovation. Pure, mixed,
enriched, and genetically engineered microorganisms have been
used for degradation of the complex compounds.
We can subdivide these microorganisms into the
following groups:
Aerobic : Alcaligenes, Sphingomonas, Rhodococcus, and
Mycobacterium.
Anaerobic : Anaerobic bacteria are used for bioremediation of
polychlorinated biphenyls(PCBs) in river sediments,
dechlorination of the solvent trichloroethylene(TCE) and
chloroform.
Ligninolytic fungi : Phanaerochaete chrysosporium

13. I. Nutrient availability : Inorganic nutrient such as
nitrogen and phosphorus are necessary for microbial
activity and cell growth. It has been shown that “treating
petroleum-contaminated soil with nitrogen can increase
cell growth rate, decrease the microbial lag phase, help
to maintain microbial populations at high activity levels,
and increase the rate of hydrocarbons degradation”.
II. Moisture content : All soil microorganisms require
moisture for cell growth and function. Availability of
water affects circulation of water and soluble nutrients
into and out of microorganisms cells. However, excess
moisture, such as in saturated soil, is undesirable
because it reduces the amount of available oxygen for
aerobic respiration.

14. III. pH : pH of soil is important because survival of
most microbial species are limited to a certain pH
range. In addition, soil pH can affect availability of
nutrients
IV. Temperature : Temperature influence rate of
biodegradation by controlling rate of enzymatic
reactions within microorganisms. Generally , “speed
of enzymatic reactions in the cell approximately
doubles for each 100 c rise in temperature”. Most of
bacteria found in soil, including many bacteria that
degrade petroleum hydrocarbons , are mesophiles
which have an optimum temperature ranging from
250 c to 450 c.

15.  Bioremediation is a natural process and is therefore
perceived by the public.
 Bioremediation is useful for the complete destruction
of a wide variety of contaminants.
 Instead of transferring contaminants from one
environmental medium to another, for example, from
land to water or air, the complete destruction of target
pollutants is possible.
 Bioremediation can often be carried out on site, often
without causing a major disruption of normal activities.
 Bioremediation can prove less expensive than other
technologies that are used for cleanup of hazardous
waste.

16.  Bhattacharya B.C., Banerjee. 2007. Environmental
Biotechnology. Oxford university press. Pp 338.
 Dubey R.C. 1993. Biotechnology. S. Chand and
company ltd. New Delhi. Pp 702.
 Mohanty M.K. 2008. Environmental Biotechnology.
Adhyayan publishers and Distributors. New Delhi. Pp
257.
 Thakur I.S. Environmental Biotechnology. 2nd edition.
I.K. International publishing house pvt.ltd. New Delhi.
Pp 516.
 Www. Iupac.org> publications >pac > pdf.

17.  Bioremediation is limited to those compounds that are
biodegradable. Not all compounds are susceptible to
rapid and complete degradation.
 There are some concerns that the products of
biodegradation may be more persistent or toxic than
the parent compound.
 Biological process are often highly specific. Microbial
populations, suitable environmental growth conditions,
and appropriate levels of nutrients and contaminants.
 It is difficult to deduce from bench and pilot-scale
studies to full scale field operations.
 Bioremediation often takes longer than other
treatments options.

18. Bioremediation is a waste management
technique which involves the use of biological
organisms to remove or neutralize pollutants from
the contaminated site. Bioremediation is a treatment
that uses naturally occurring organisms to
breakdown hazardous substance into less toxic or
non toxic substance.
Technology generally classified as in situ and ex
situ Bioremediation. In situ Bioremediation involves
removal contaminated material at the site. And Ex
situ bioremediation involves the removal of the
contaminated material to be treated elsewhere.

19.  Bioremediation is a eco – friendly technology.
 It is effective process.
 Recovery of a contaminated medium by using
living microorganisms.
 Approach to enhance the degrading
capability.
 Application in all types of contaminated
fields.