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