Bioremediation

Bioremediation

Presented By,Ananya Azad Hrisha

Objectives• Bioremediation• How it works?• Essential Factors for microbial Bioremediation• Bioremediation Methods & Types • Microbes involved in Bioremediation• Advantages & Disadvantages of

Bioremediation• Application of Bioremediation• Some Bioremediation related technologies.

What is Bioremediation?

• "Remediate" means to solve a problem, and "bio-remediate" means to use biological organisms to solve an environmental problem such as contaminated soil or groundwater.

• Bioremediation means to use a biological remedy to abate or clean up contamination.

• Bioremediation is a waste management technique that involves the use of organisms to remove or neutralize pollutants from a contaminated site.

• According to the EPA, bioremediation is a “treatment that uses naturally occurring organisms to break down hazardous substances into less toxic or non toxic substances”.

What is Bioremediation?• Bioremediation is the a biological degrading processes for the treatment of

contaminated soils, groundwater and/or sediments, relying on microorganisms including bacteria and/or fungi to use the contaminant(s) as a food source with resulting degradation of the contaminant.

• Microorganisms used to perform the function of bioremediation are known as bioremediators.

• Bioremediation is one of the most economic remedial techniques presently available for treating most organic fuel based contaminants such as coal tars and liquors, petroleum and other carcinogenic hydrocarbons such as benzene and naphthalene, and some inorganics.

Organisms

Pollutants

Environments

Inorganic OrganicSolid

Liquid

Gas

Soil

Water

Air

Microorganisms

Plants

Enzymes

How Does It Work?

• Waste material is examined & certain bacteria are isolated based on their efficacy at digesting and converting the waste.

• Indigenous or local bacteria is to be used!• The bacteria then go through several

steps of cultures and process for performance testing.

• The suitable bacteria are placed back in the waste environment.

• They grow & thrive & in the process digest & convert the waste into Carbon dioxide & water.

• The right temperature, nutrients, and food also must be present.

• Conditions may be improved by adding “amendments.”

ESSENTIAL FACTORS FOR MICROBIAL BIOREMEDIATION

Factor Desired Conditions

Microbial population Suitable kinds of organisms that can biodegrade all of the contaminants

Oxygen Enough to support aerobic biodegradation (about 2% oxygen in the gas phase or 0.4 mg/liter in the soil water)

Water Soil moisture should be from 50–70% of the water holding capacity of the soil

Nutrients Nitrogen, phosphorus, sulfur, and other nutrients to support good microbial growth

Temperature Appropriate temperatures for microbial growth (0–40˚C)

pH Best range is from 6.5 to 7.5

Bioremediation

In situ- At the site

-treatment of contaminated material in place

- Ex – Benzene, Toluene, TNT, 2,4-D

- only certain types of soils can be bioremediated in-situ

- complete degradation is often difficult to achieve

- Away from site- Techniques involve physical removal of the contaminated

material for treatment process- Ex- Bio-piles, soil treatment unit,

Compost pile , Windrows etc. &-use of bioreactors to process the

material in a highly controlled environment.

Ex Situ

TYPES OF BIOREMEDIATION :

1. Biostimulation 2. Bioaugmentatio

n

3. Intrinsic Bioremediation

• The method in which bacteria are motivated to start the process of bioremediation.

• In this method, first the experts release nutrients and other important substances in the soil where there is need or removing the contaminants.

• These are in the form of gas or liquid. It increases the growth of microbes in that area.

• As a result bacteria and other microorganisms remove the contaminants quickly and efficiently.

• Microorganisms that can clean up a particular contaminant are added to the contaminated soil and water.

• Bioaugmentation is more commonly and successfully used on contaminants removed from the original site, such as municipal waste water treatment facilities.

• Process takes place in soil and water because these two places are always full of contaminants and toxins.

• This process is also called as natural attenuation.

• Also means use of the microorganisms to remove the harmful substances from soil and water.

• Especially those sites are treated with this method, which are underground, for example underground petroleum tanks.

Bioremediation by Bacteria

Genetically engineered bacteria (Pseudomonas) with plasmid producing enzymes to degrade octane and many different organic compounds from crude oil.

• A selected list of genetically engineered microorganisms.

Candida can degrade formaldehyde. Gibeberella can degrade cyanide. White rot fungi can degrade organic

pollutants in soil and effluent and decolorize kraft black liquor, e.g. Phanerochaete chrysosporium can produce aromatic mixtures with its lignolytic system.

Pentachlorophenol,dichlorodiphenyltrichloroethane (e.g. DDT), even TNT (trinitrotoluene) can be degraded by white rot fungi.

Bioremediation by Fungi

METABOLIC EFFECT OF MO’S ON XENOBIOTICS:

¤ Detoxification ¤ Activation ¤ Degradation ¤ Conjugation

Monitoring Bioremediation Process

Advantages:• Low cost.• Minimal site disruption.• Simultaneous treatment of contaminated

water and soil.• Minimal exposure of public & site

personnel.• Useful for the complete destruction of a

wide variety of contaminants. • Can often be carried out on site, often

without causing a major disruption of normal activities

• Can prove less expensive than other technologies that are used for cleanup of hazardous waste.

Disadvantages:• Time consuming.• Seasonal variation.• Problematic addition of additives.• Limited to those compounds that are

biodegradable. • Not all compounds are susceptible to

rapid and complete degradation. • There are some concerns that the

products of biodegradation may be more persistent or toxic than the parent compound.

• difficult to extrapolate (deduce) from bench and pilot-scale studies to fullscale field operations.

• Biological processes are often highly specific. microbial populations, suitable environmental growth conditions, and appropriate levels of nutrients and contaminants.

Applications of BioremediationBioremediation is used in following

ways: Bioremediation of contaminated soil Bioremediation of aquifer Bioremediation of marine oil

pollutants Bioremediation of industrial waste

Slurry-phase bioremediation is useful too but only for small amounts of contaminated soil.

Composting can be used to degrade household wastes.

Environmental cleanup

Joint action of Govt.(various

ministries and their

departments)

Novel lab level

research

Pilot Scale experiments

Bioremediation of Contaminated Soil

In-situ bioremediation of soil:• Allows treatment of a large volume

of soil at once.• Mostly effective at sites with sandy

soils.• Can vary depending on the method

of supplying oxygen or electron donors to the organisms that degrade the contaminants.

• Three commonly used in-situ methods include: Bioventing Injection of hydrogen peroxide or oxygen

releasing compound (ORC) for aerobic treatment

Injection of HRC for anaerobic treatment

Ex-situ Bioremediation of soil:• Involves excavation of the

contaminated soil and treating in a treatment plant located on the site or away from the site.

• This approach can be faster, easier to control, and used to treat a wider range of contaminants and soil types than in-situ approach.

• Ex-situ bioremediation can be implemented as: Slurry-phase bioremediation, or Solid-phase bioremediation

Contained Solid Phase

Composting

Land farming

• In slurry-phase bioremediation - the contaminated soil is mixed with water to create a slurry. The slurry is aerated, and the contaminants are aerobically biodegraded. The treatment can take place on-site, or the soils can be removed and transported to a remote location for treatment. The process generally takes place in a tank or vessel (a "bioreactor"), but can also take place in a lagoon.

• In solid-phase bioremediation - soil is treated above ground treatment areas equipped with collection systems to prevent any contaminant from escaping the treatment. Moisture, heat, nutrients, or oxygen are controlled to enhance bioremediation for the application of this treatment.

• Solid-phase systems are relatively simple to operate and maintain, require large amount of space, and cleanups require more time to complete than slurry-phase processes.

Bioremediation of Contaminated Soil

Bioremediation of Contaminated Soil

Bioremediation of Aquifer• In situ bioremediation (ISB) of groundwater involves the encouragement of indigenous

bacterial populations to metabolize target contaminants through the addition of various amendments (biostimulation) to the subsurface environment.

• In addition to amendments, select strains of bacteria may be added to the subsurface to help treat some sites (bioaugmentation).

• Bacteria perform coupled oxidation/reduction (redox) reactions to live, and bioremediation exploits these reactions to remove contaminants from contaminated media (groundwater).

• Bacteria can use different electron acceptors (oxidized compounds) and donors (reduced compounds) in the three major oxidation pathways — • Aerobic respiration, • Anaerobic respiration, and • Fermentation.

• ISB can use all of these pathways, and contaminant degradation may occur through • Direct metabolism, • Cometabolism, or • Abiotic transformations that may result from biological activities.

Bioremediation of Aquifer

Bioremediation of Aquifer

Bioremediation of Marine Oil Spills

• Useful process for removing marine oil pollutants.• The application of oleophilic fertilizer is a useful bioremediation strategy.• Marine oil spills are very catastrophic events which pose a great threat on the affected

environment. • Marine oil spills are mainly oils, petroleum, fuel etc. composed of complex hydrocarbons.• Addition of microbial seeding or inoculum that are capable of degrading hydrocarbons.• Most microorganisms considered for seeding are obtained from enriched cultures (from a

previously contaminated site).• After inoculum addition, fertilizer is added, then environmental modification is done ,

adequate aeration, nutrient source is a prerequisite.• Bioremediation for marine oil spills can be approached in two different ways depending on

the case at hand. This includes bioaugmentation which involves introducing oil degrading microorganisms to the affected site, and also biostimulation which involves adding supplemental nutrients to the affected site to aid the existing oil degrading microorganisms.

Bioremediation of Marine Oil Spills

Bioremediation of Marine Oil Spills

Bioremediation of Air Pollutants

Bioremediation of Air Pollutants• Microorganisms are used for air emission control in 3 types of devices:

a. Biofilterb. Bioscrubbersc. Trickling Filter

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Bioremediation related technologies

• Phytoremediation - bioremediation through the use of plants that mitigate the environmental problem without the need to excavate the contaminant material and dispose of it elsewhere.

• Bioventing - an in situ remediation technology that uses microorganisms to biodegrade organic constituents in the groundwater system.

• Bioleaching - the extraction of metals from their ores through the use of living organisms.

• Landfarming - an ex-situ waste treatment process that is performed in the upper soil zone or in biotreatment cells.

• Bioreactor - any manufactured or engineered device or system that supports a biologically active environment.

• Vermicomposting - using various worms, usually red wigglers, white worms, and other earthworms to create a heterogeneous mixture of decomposing vegetable or food waste, bedding materials, and vermicast.

• Rhizofiltration - is a form of phytoremediation that involves filtering water through a mass of roots to remove toxic substances or excess nutrients.

References• Microbial Ecology by Atlas & Bartha• Various Webpages including:• Wikipedia • http://ei.cornell.edu/biodeg/bioremed/• http://www.pollutionissues.com/A-Bo/Bioremediation.html• http://www.soilutions.co.uk/services/soil-remediation/bioremediation /• http://www.slideplayer.com/slide/1523117/#• http://krockne.people.uic.edu/proceeding9.pdf• https://

clu-in.org/download/remed/introductiontoinsitubioremediationofgroundwater_dec2013.pdf

• http://home.engineering.iastate.edu/~tge/ce421-521/matt-r.pdf

• A Citizen’s Guide To Bioremediation