Basic Civil Engineering first year Notes- Chapter 4 Building.pptx
Bioremediation
1.
2. Conventional methods of remediation
Conventional methods of remediation
Dig up and remove it to a landfill Cap
and contain
Risk of excavation, handling and
transport of hazardous material
Very expensive to find another land to
finally dispose these materials
Maintain it in the same land but
isolate it
3. Only an interim solution
Requires monitoring and
maintenance of isolation
barriers for a long time
Is there a better approach?
Products are not converted
into harmless products. Stay
as a threat!
4. Better approaches :
Destroy them completely, if
possible Transform them in to
harmless substances
High temperature incineration
Chemical decomposition like
dechlorination,
UV oxidation Methods already
in use
5. Bioremediation makes
effective better approach
possible. Either by
destroying or render them
harmless using natural
biological activity.
6. Relatively low cost
Low technology techniques
Generally has general public acceptance
Can often be carried out on site – no
excavation, no transport
Drawbacks
May not be effective on all contaminants
Time duration – relatively long
Expertise required to design and
implement – although not technically
complex
7. Bioremediation :
is defined as the process
whereby organic wastes are
biologically degraded under
controlled conditions to an
innocuous state, or to levels
below concentration limits
established by regulatory
authorities
9. Qualities of :
Qualities of Microorganisms
Environment
Able to degrade hydrocarbons
Able to fix nitrogen No secondary/side
effects
Presence of accessory nutrients (N P K
Fe)
Absence of heavy metals Adequate
O2, Temperature, pH
10. Sources of microorganisms :
From contaminated field sites (with
varying environmental conditions -
subzero temperatures or extreme
heat, desert conditions or in water, with
excess of oxygen or in anaerobic
conditions, with presence of hazardous
compounds or on any waste stream)
From culture collections Genetically
Engineered Microorganisms (GEMs)
Sources of microorganisms
12. Bioaugmentation involves
practice of adding specialized
microbes or their enzyme
preparation to polluted
matrices to accumulate
transformation or stabilization
of specific pollutants
13. Ex situ bioremediation types :
Ex situ bioremediation types
Landfarming involves a simple
technique in which
contaminated soil is excavated
and spread over a prepared
bed and periodically tilled until
pollutants are degraded.
14. Phytoextraction :
Phytoextraction Also called
Phytoaccumulation
A process used by the plants to
accumulate contaminants into
the roots and shoots or leaves.
15. Phytotransformation :
Phytotransformation also called
Phytodegradation refers to the
uptake of organic contaminants
from soil, sediments, or water
and, subsequently, their
transformation to more stable, less
toxic, or less mobile form. Metal
chromium can be reduced from
hexavalent to trivalent
chromium, which is a less mobile
and non-carcinogenic form.
16. Phytostabilization :
Phytostabilization Leachable
(permeate gradually)
constituents are adsorbed and
bound into the plant structure
so that they form a stable mass
of plant from which the
contaminants will not reenter
the environment
17. Phytodegradation :
Phytodegradation also called
rhizodegradation is the breakdown of
contaminants through the activity existing
in the rhizosphere. Due to the presence of
proteins and enzymes produced by the
plants or by soil organisms such as
bacteria, yeast, and fungi. a symbiotic
relationship that has evolved between
plants and microbes Plants provide
nutrients necessary for the microbes to
thrive, while microbes provide a healthier
soil environment.
18. Rhizofiltration :
Rhizofiltration is a water
remediation technique that
involves the uptake of
contaminants by plant roots used
to reduce contamination in
natural wetlands and estuary
areas The wide part of a river
where it nears the sea; fresh and
salt water mix
19. Phytoremediation is well suited
for :
Phytoremediation is well suited for use
at very large field sites where other
methods of remediation are not cost
effective or practicable use at sites
with a low concentration of
contaminants where only polish
treatment is required over long periods
of time in conjunction with other
technologies where vegetation is used
as a final cap and closure of the site
