BIOREMEDIATION A. SCHOOL OF EARTH AND ENVIRONMENTAL SCIENCE BY: P.K.Kr M.Sc (ESM)
BIOREMEDIATION A. SCHOOL OF EARTH AND ENVIRONMENTAL SCIENCE
BY: P.K.Kr
M.Sc (ESM)
What Is BIOREMEDIATION?
The process of using specific microorganisms to transform hazardous contaminants in soil/water to nonhazardous waste products.
Present state of our environment
• Rapid industrialization and urbanization • Contamination of all the components of
the environment • Generation of a plethora of synthetic
organic compounds • Fugitive emissions, accidental spills and
leaks, discharge of effluents • Degradation of nature
Potential hazards
• Short-term hazard: Direct contacts, inhalation of toxic dust/fumes or immediate risk of fire/explosion
• Long-term hazard: Resulting by movement to other components of the environment or generation of secondary toxic products
Solutions
• Prevention is always better than cure • Cleaner Production • Cleaner processes • Biotechnological approaches
Mechanism of Bioremediation
Uses naturally occurring microorganisms to break down hazardous substances into less toxic or nontoxic substances.
Types Of Bioremediation
• In situ bioremediation - material to be bioremediated dosesn’t leave the site.
• Ex situ bioremediation - material to be bioremediated is moved to another site to be treated.
CONTAMINANTS ..BREAK DOWN BIOREMEDIATION
• Petroleum hydrocarbons o Gasolineo Diesel Fuelo Gasoline Additives
• Halocarbons o Chlorinated Aliphatics: trichlorethyleneo Chlorinated Aromatics : PCB’s, Pentachlorophenol
• Nitroaromatics o Ammonia or Nitrate/Nitrite
Table : Microorganisms (Pure cultures) helpful in bioremediation
Pollutant Microorganism
Atrazine Pseudomonas sp. strain Acinetobacter species
Chlorpyrifos Aspergillus niger
2,4,6-Trichlorophenol Alcaligenes eutrophus TCP
2,4-Dichlorophenoxyacetic acid Ralstonia eutropha
Carbon tetrachloride Pseudomonas stutzeri KC
Methyl tert-butyl ether Hydrogenophaga flava ENV735
BTEX B. sp. Strain JS150 B. Cepacia G4
Orange 3, 4-(4-nitrophenylazo) aniline Pleurotus ostreatus
BIOREMEDIATION TECHNOLOGIES
In situ bioremediation Techniques
1.BIOVENTING Venting of oxygen
through soil to stimulate growth of natural or introduced microorganisms .
2.BIOAUGMENTATION • Addition of pollutant-
degrading microorganisms to augment the biodegradative capacity of indigenous microbial populations .
3.BIOSPARGING• Injection of air under
pressure below the water table.
Ex situ bioremediation Techniques
1.LAND FARMING Contaminated soil is
excavated & spread over the prepared bed where beneficial microorganisms are present.
2.COMPOSTING
Aerobic, thermophilic treatment process in which contaminated material is mixed with a bulking agent .
3.BIOREACTORS Biodegradation of
contaminants in a large tank or reactor. Bioreactors can be used to treat liquid effluents/slurries or contaminated solid waste/soil.
Advantages of Bioremediation• Can be highly specific• Less expensive than excavation or incineration
processes• If mineralization occurs get complete
degradation and clean up• Does not transfer contaminants from one
environment to another• Uses a natural process• Good public acceptance• Process is simple• If using ISB you will treat the groundwater
and soil at the same time
Disadvantages to Bioremediation• Not instantaneous• Often need to develop a system• Always need to test and optimize conditions
empirically – not with computer models• May have inhibitors present• Compounds may not be in a biodegradable
form – polymers, plastics• Compounds may be recalcitrant – higher
congeners of PCBs
THANK YOU
SUBMITTED TO : ASEES