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bioremediation ..special emphasis on methodologies


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BIOREMEDIATION 4/17/2013 1 Ashok kumar J yoti priya B.Sc.[agricultural biotechnology] College of agriculture, Hassan University of agricultural sciences, Bangalore

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Bioremediation Ashok kumar [BTL(H)002] Ashwat [BTL(H)003] Avinash M[BTL(H)004] Bharath K.N.[BTL(H)005] 4/17/2013 2


What is BIOREMEDIATION ? BIO REMEDIATION method to fix microbial Using microorganisms to clean up pollution in the environment 4/17/2013 3

Biogeochemical cycle influenced by man:

Biogeochemical cycle influenced by man 4/17/2013 4


DEFINTION !! “Use of living organisms to transform, destroy or immobilize contaminant” Goal: Detoxification of the parent compound(s) and conversion to products that are no longer hazardous to human health and the environment 4/17/2013 5

Biodegradation Vs. Bioremediation:

Biodegradation Vs. Bioremediation Biodegradation refers to the natural process whereby bacteria or other microorganisms alter and break down organic molecules into other substances , such as fatty acids and carbon dioxide. bioremediation is the act of adding materials to contaminated environments, such as oil spill sites, to cause an acceleration of the natural biodegradation process. -- it include Fertilization and seeding 4/17/2013 6

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“Bioremediation is the use of biological interventions of biodiversity for mitigation (and wherever possible complete elimination) of the noxious effects caused by environmental pollutants in a given site” Moef govt. of india 4/17/2013 7


History 1972 - First commercial application: Sun Oil pipeline spill in Ambler, Pennsylvania 1970s - Continuing bioremediation projects by Richard Raymond of Sun Oil mid-1980s - emphasis on bioengineering organisms for bioremediation. This technology did not live up to its initial promise 1990s - emphasis switched to greater reliance on natural microorganisms and techniques to enhance their performance 4/17/2013 8

Bioremediation Background:

Bioremediation Background Natural Attenuation is Not fast enough, Not complete enough, Not frequently occurring enough to be broadly used for some compounds, especially chlorinated solvents The current trend is to stimulate/enhance a site’s indigenous subsurface microorganisms by the addition of nutrients and electron donor In some cases, bioaugmentation is necessary when metabolic capabilities are not naturally present. 4/17/2013 9

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Why Microbes ??:

Why Microbes ?? Typically very rapid if food (carbon source) is present: population doubles every 45 minutes Pristine soils contain 100 to 1000 aerobic bacteria per gram of soil Increases to 10 5 within one week if carbon source is introduced 4/17/2013 11

Examples of microbes used for bioremediation include::

Examples of microbes used for bioremediation include: Deinococcus radiodurans bacteria have been genetically modified to digest solvents and heavy metals, as well as toluene and ionic mercury from highly radioactive nuclear waste. Geobacter sufurreducens bacteria can turn uranium dissolved in groundwater into a non-soluble, collectable form. Dehalococcoides ethenogenes bacteria are being used in ten states to clean up chlorinated solvents that have been linked to cancer. The bacteria are naturally found in soil. 4/17/2013 12

Uranium reduction leads to uranium precipitation and immobilization:

Uranium reduction leads to uranium precipitation and immobilization U 6+ sol U 4+ insol U 6+ sol U 6+ sol U 4+ insol 4/17/2013 13

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Thermus brockianus : An enzyme from this bacterium ,, found in Yellowstone National Park, breaks down hydrogen peroxide 80,000 times faster than current chemicals in use. The bacterium, Alcaligenes eutrophus , naturally degrades 2,4-D , the third most widely used herbicide in the U.S. 4/17/2013 14

Method depending on nature of contaminants:

Method depending on nature of contaminants 4/17/2013 15

Types of bioremediation:

Types of bioremediation In-situ bioremediation If the process occurs in the same place affected by pollution then it is called in-situ bioremediation. ex- Bioventing In situ biodegradation Bio stimulation Bio sparging Bio augmentation Natural Attenuation 4/17/2013 16

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degradation of crude oil by halophilic Archaea 4/17/2013 17

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Continue… 2. Ex-situ bioremediation:- deliberate relocation of the contaminated material (soil and water) to a different place to accelerate bio catalysis is referred to as ex-situ bioremediation Land farming Composting Biopiles Bioreactors 4/17/2013 19


3 . Intrinsic Bioremediation :- bioremediation can be accomplished without human intervention by microorganisms that are naturally found in the contaminated matrix. - the rate of contaminant degradation sud exceed the rate of contaminant migration . - the bioavailability of contaminants, levels of nutrients, the pH of the matrix, adequate levels of electron acceptors (either oxygen , nitrate, ferric iron, or sulfate ), and site specific contamination migration rates. Continue… 4/17/2013 20


4.Engineered Bioremediation :- it may be desirable to construct engineered systems to supply nutrients, electron acceptors or other materials that enhance the rate or extent of contaminant degradation. This is to achieve faster rate To translocate the final product When there is a threat of migration of contaminants All the factor of natural attenuation remains same Continue… 4/17/2013 21

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In-situ bioremediation:

In-situ bioremediation 4/17/2013 23


Bioventing The system supplies oxygen by injecting air directly into the residual contamination . bioventing uses low airflow rates to provide only enough oxygen to sustain microbial activity. Optimal flow rates maximize biodegradation as vapors move slowly through biologically active soil while minimizing volatilization of contaminants. It works for simple hydrocarbons and can be used where the contamination is deep under the surface. A basic bioventing system includes a well and a blower---which pumps air through the well and into the soil. 4/17/2013 24

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One of the most common approaches in soil Supply air and nutrients via wells Takes advantage of indigenous microorganisms 4/17/2013 26

In situ biodegradation:

In situ biodegradation Supply air and nutrients by circulating aqueous solutions through contaminated soils or groundwater Contaminants are composed of simple carbons. Can be attenuated by natural microrganism . Some limiting factors like aeration etc is provided 4/17/2013 27

Bio stimulation:

Bio stimulation “bioremediation method of adding nutrients, such as nitrogen and phosphorus, to a contaminated environment to stimulate the growth of indigenous microorganisms”. This approach is also termed nutrient enrichment or fertilization. It also utilizes natural microflora & fauna. Natural attenuation is going on but rate is extremely slow 4/17/2013 28


Biosparging 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. The ease and low cost of installing small-diameter air injection points allows considerable flexibility in the design and construction of the system. 4/17/2013 29

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Bio augmentation:

Bio augmentation addition of microorganisms indigenous or exogenous to the contaminated sites for better remediation and faster rate. Two factors limit the use of added microbial cultures in a land treatment unit: 1) nonindigenous cultures rarely compete well enough with an indigenous population to develop and sustain useful population levels and 2) most soils with long-term exposure to biodegradable waste have indigenous microorganisms that are effective degrades if the land treatment unit is well managed. Provide a chance of utilizing efficient strain of microbes. 4/17/2013 31

Ex-situ bioremediation:

Ex-situ bioremediation 4/17/2013 32

Land farming:

Land farming Contaminated soil is excavated and spread over land Soil is periodically tilled to improve aeration Remediation due to indigenous microorganisms, as well as chemical and physical processes Generally limited to the superficial 10–35 cm of soil Can reduce monitoring and maintenance costs 4/17/2013 33


Composting No need to waste time 4/17/2013 34


Biopiles 4/17/2013 35


Biopiles are a hybrid of landfarming and composting. engineered cells are constructed as aerated composted piles. Typically used for treatment of surface contamination with petroleum hydrocarbons they are a refined version of landfarming that tend to control physical losses of the contaminants by leaching and volatilization. Biopiles provide a favorable environment for indigenous aerobic and anaerobic microorganisms 4/17/2013 36

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Economics of in-situ vs. ex-situ remediation of contaminated soils:

Economics of in-situ vs. ex-situ remediation of contaminated soils Cost of treating contaminated soil in place $80-$100 per ton Cost of excavating and trucking contaminated soil off for incineration is $400 per ton. Over 90% of the chemical substances classified as hazardous today can be biodegraded. 4/17/2013 38


FACTORS AFFECTING CONTAMINANT BIODEGRADABILITY Simple hydrocarbons and petroleum fuels degradability decreases as molecular weight and degree of branching increase Aromatic hydrocarbons one or two ring compounds degrade readily, higher molecular weight compounds less readily Alcohols, esters Nitrobenzenes and ethers degrade slowly Chlorinated hydrocarbons decreasing degradability within increasing chlorine substitution – highly chlorinated compounds like PCBs and chlorinated solvents do not appreciably degrade aerobically Pesticides are not readily degraded b I o d e g r a d I b i l i t y 4/17/2013 39

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synthetic chemicals with either carbon-chlorine or carbon-fluorine bonds are typically metabolized slowly and some are highly recalcitrant (i.e. resist biodegradation ). Ex- polychlorinated biphenyls, chlorinated solvents chlorinated aromatic compounds. 4/17/2013 40



Site Evaluation and Factors Affecting Contaminant Degradation:

Site Evaluation and Factors Affecting Contaminant Degradation Biological factor Rates of Contaminant Degradation dependent on the concentration of the contaminant and the amount of “catalyst” present Extent of Contaminant Degradation is largely a function of the specific enzymes involved and their “affinity” for the contaminant and the availability of the contaminant General Indicators and Microbial Physiology C:N:P Ratios Sufficient amounts of these nutrients must be available in a usable form and in proper proportions for unrestricted microbial growth to occur[ 50:14:3 ] Nutrient Availability the total number of organisms present is proportional to the amount of carbon available microbial density of surface soils is greater than subsurface soils Terminal Electron Acceptors Aerobic:- O 2 Anaerobic:- NO3, Fe+3, Mn+3, SO4-2 , Soil Respirometry a measure of oxygen consumption or carbon dioxide production in soils and is an indication of net aerobic biological activity in situ Temperature Moisture pH 4/17/2013 42

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Electron Acceptor Zones:

Electron Acceptor Zones After O 2 is depleted, begin using NO 3 – Continue down the list in this order O 2 ––> NO 3 – ––> Fe 3+ ––> SO 4 2– ––> CO 2 Ground Water Flow Plume of Dissolved Fuel Hydrocarbons Residual NAPL Mobile LNAPL Pool Methanogenesis Sulfate Reduction Iron (III) Reduction Dentrification Aerobic Respiration 4/17/2013 45

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ATP ACETATE CO 2 Fe(III) Fe(II) Metabolism of a Pollutant-degrading Bacterium *Benzoate *Toluene *Phenol *p -Cresol *Benzene *U(VI) *Co(III) *Cr(VI) *Se(VI) * Pb (II) * Tc (VII) *CCl 4 * Cl-ethenes * Cl -aromatics *Nitro-aromatics 4/17/2013 46


Continued… 2. Environmental Factors a] Geologic and Hydrogeologic Factors Adsorption and Absorption “Both adsorption and absorption reduce the availability of the contaminant to most microorganisms and the rate at which the chemical is metabolized is proportionately reduced” Contaminant Migration in Groundwater controlled by many chemical and physical properties of the contaminants Hydraulic conductivity is one of the primary aquifer characteristics B]Bioavailability The fraction of contaminant actually available to microorganisms is said to be bioavailable C]Soil Matric Potential The soil matric potential is a measure of the energy required to overcome capillary and adsorptive forces and thus reflects the “work” that microbial cells must do to extract water from the soil. D]Redox Potential The oxidation-reduction potential (redox potential) of a soil provides a measurement of the electron density of the system . Low Eh – aerobic high Eh – anaerobic condition 4/17/2013 47

Site evaluation for bioremediation:

Site evaluation for bioremediation There are at least five critical factors that should be considered when evaluating the use of bioremediation for site clean up . Magnitude, toxicity, and mobility of contaminants Proximity of human and environmental receptors Degradability of contaminants . Planned site use Ability to properly monitor 4/17/2013 48

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Potential Advantages of bioremediation:

Potential Advantages of bioremediation Lower cost than conventional technologies. Contaminants usually converted to innocuous products. Contaminants are destroyed, not simply transferred to different environmental media. Nonintrusive , potentially allowing for continued site use. Relative ease of implementation. 4/17/2013 50

Disadvantages of Bioremediation:

Disadvantages of Bioremediation May be difficult to control. Amendments introduced into the environment to enhance bioremediation may cause other contamination problems. May not reduce concentration of contaminants to required levels. Requires more time. May require more extensive monitoring. Lack of (hydraulic) control. Dynamic process, difficult to predict future effectiveness 4/17/2013 51

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Treating contaminated soils on-site at bioremediation facilities is ultimately less expensive and more environmentally friendly 4/17/2013 52

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Different stages of bioremediation of oil sludge. Source: Dr. McIntyre T., Environment Canada 4/17/2013 53

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Constructed wetland at NALCO’s Angul plant in Orissa for treatment of coal fly ash slurry released from captive power plant 4/17/2013 54


Reference……………………………………. No need to go any where Don’t u have faith on yr friends Mention not “most doubtful person contact me I will give all the soft copy” 4/17/2013 55

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