3. BIOREMEDIATION Bioremediation is the productive utilization of living systems to degrade, detoxify, transform, immobilize or stabilize toxic environmental contaminants Goal ---- to degrade the pollutants that are either undetectable or if detectable to concentrations that are safe or acceptable by the regulatory agencies RENOVOGEN – NEXT GENERATION BIOREMEDIATION
4. BIOREMEDIATION STRATEGIES Addition of genetically modified organisms Use of indigenous microorganisms Biostimulation Bioaugmentation Phytoremediation
5. Gene Manipulation Gene responsible for the degradation of a pollutant, is introduced or altered and expressed in the suitable bacteria e.g. E coli Gene opd of Flavobacterium encoding proteins responsible for the degradation of carbonates are introduced in fungi , Gliocladiumvirens, who expresses the gene
6. Gene Manipulation Enterobacteragglomerans DK3 containing plasmid RP-4 Tn 4371 , encodes for Biophenyl degradation This donar strain when added to the soil disappears quickly, but the plasmid is transferred to the other microbes present, which carry out the biophenyl degradation
7. Use of Indigenous Microorganisms Soil harbours a number of microorganisms with degradative potential Microbes are ubiquitous in distribution The have developed enzymatic systems to tackle environmental contaminants
8. Use of Indigenous Microorganisms Cyanobacteria and algae – hydrocarbons Pseudomonas putida – can degrade benzoate completely Rate of degradation depends upon the structure of the compound Central chronicle (M.P) : sewage near her KautilyaMarg residence in New Delhi.
9. Bioaugmentation Bioaugmentation is addition of selected organisms to the contaminated site in order to supplement indigenous microbial population and speed up degradation Bioaugmentation has been successfully carried out by using activated soil rather than pure cultures Activated soil – soil containing indigenous microbial population recently exposed to contaminants
10. Bioaugmentation Activated soil containing various bacteria have been used to degrade : Pentachlorophenol Atrazine Chloro benzoate
11. Biostimulation Biostimulation is the stimulation of indigenous microbial growth by providing them with necessary nutrients Principle : Microbes cannot use pollutants as a sole source of energy. Hence they need to be provided with other essential nutrients
12. Biostimulation Biosurfactants have been used to solubilize oil and xenobiotics (PCB and Organophosphates) Acinetobacterradioresistens produces a protein bioemulsifier – Alasan Alasansolubilizes PAHS Principle : the gene is cloned and expressed in Escherichia coli
13. Bioaugmentation Field Testing for MTBE Treatment (US) : Naval Facilities Engineering Service Center, California The ether-metabolizing bacterial culture was grown on an MTBE enriched activated sludge culture for three to four months at ambient outdoor temperatures Biostimulation – Degradation of Hydrocarbon Contaminated Soils at Crude Oil Production Sites in West Texas and New Mexico - Amoco Production Co.
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15. Phytoremediation Phytoremediation is the use of plants for the removal of contaminants and metals from the soil and water, or to render them harmless It is basically the decontamination or stabilization of the polluted area using plants
16. Chernobyl Sunflower Project - 1994 It is carried out by Phytotech, a phytoremediation company in Monmouth Junction, N.J. Rafts with sunflowers growing on them float on a small pond at the Chernobyl nuclear accident site in the Ukraine. The roots dangle in the water to suck up the cesium 137 and strontium 90. This sunflower project is one of many international efforts at phytoremediation Government Agencies and Private Companies: Exxon Corp. DuPont
17. Process involved in Phytoremediation Phytoextraction Phytodegradation Phytovolatilization Phytostabilization
18. Phytoextraction Phytoextraction is the removal of contaminants and metals from the soil and their storage in plants It is also known as Phytoaccumulation Sunflower – used for uranium removal Water hyacinth – detoxification of copper Poppler - trichloroethylene
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20. Chelate assisted phytoextraction of heavy metals from soil Chelate based has often been described as a promising technique to remediate heavy metal from contaminated agricultural land The application of chelating agents has shown positive effects in increasing the solubility of heavy metals in soil and therefore in enhancing phytoextraction Various synthetic aminopolycarboxylic acids, such as ethylene diaminetetraacetic acid, and natural ones such as, ethylene diaminedisuccinate and nitrilotriacetic acid Phytoextraction
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22. Algal phytodegradation of petroleum naphthenic acid Water Science and Technology Division, Environment Canada, Saskatoon The algal phytodegradation of a model naphthenic acid (4-methylcyclohexaneacetic acid) and an oilsands mixture of naphthenic acids (NAs) were evaluated in support of studies to remediate recalcitrant NAs in soils and water Phytodegradation
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24. Phytovolatilization Phytovolatilization is the volatilization of the toxic pollutants into the atmosphere Some Plants have the ability to convert the toxic metal ions into volatile species Phytovolatilization reduces the toxicity and aid in disposal through the stomata Poplar Plants – Trichloroethylene Eucalyptus – methyl-t-butyl-ether (MTBE)
25. Phytostabilization Phytostabilization is the transformation of one species toxic molecule intoless toxic species or reduction of mobility Various bacteria can convert Cr+6 into less toxic Cr+3 Loliumperenne in the soil from the Iron treatment plants produced vegetative cover without the loss of the metal.
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27. Gaseous Bioremediation Gaseous bioremediation is to pass poluted gas through a vessel in which pollutants are trasferred to the water medium and further degraded by microorganisms Sources : Petrochemical indutry Pesticides Textile industry Explosives Gases like SO2, CFCs, nitrous oxides, green house gases like CO2 , CH4 are released in the atmosphere from the above sources
28. Conclusion Bioremediation, the process whereby natural degradation rates are accelerated through stimulation of indigenous microorganisms is an effective ecologically and economically effective reclamation alternative Site - specific (soil properties, geology) and contaminant – specific (composition, concentration, age, bioavailability) must be considered
