Role of microbes in bioremediation

Role of microbes in bioremediation
waseem microbiology

1. Roles of microbes in Bioremediation Presented by Hafsa , Saqib , Asif Afzal

2. Contents • 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. Conclusion References

3. "Remediate" means to solve a problem, and " bioremediate " 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?

4. 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 .

5. 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.”

6. 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

7. TYPES OF BIOREMEDIATION : 1. Biostimulation 2. Bioaugmentation 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.

8. 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.

9. 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

10. Applications of Bioremediation

11. 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 Bioremediation of Contaminated Soil

12. Bioremediation of Contaminated Soil

13. 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).

14. • 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

15. Bioremediation of Aquifer

16. 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.

17. Bioremediation of Marine Oil Spills

18. Bioremediation of Marine Oil Spills

19. Bioremediation of Air Pollutants

20. Bioremediation of Air Pollutants • Microorganisms are used for air emission control in 3 types of devices: a. Biofilter b. Bioscrubbers c. Trickling Filter

21. 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.

22. Conclusion :_ · Bioremediation is a eco-friendly technology . · It is effective process. · Recovery of contaminated medium by using living microorganisms. · Approach to enhance the degrading capability. · Application in all types of contaminated fields.

23. 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://cluin.org/download/remed/introductiontoinsitubioremediationofgroundwater_dec2013. pdf • http://home.engineering.iastate.edu/~tge/ce421-521/matt-r.pdf • A Citizen’s Guide To Bioremediation