Bioremediation

bioremediation, types, evaluation & bioremediation of VOC

1. BIOREMEDIATION DILSHANA FATHIMA M.Sc. BIOCHEMISTRY

2. INTRODUCTION Refers to the process of using micoorganism to remove environmental pollution i.e , toxic waste found in soil, water, air etc. The microbes saves as scavengers in bioremediation. The removal of organic waste by microbes for environmental cleanup is the essence of bioremediation. Other names used for bioremediation are bio treatment, bio reclamation & bio restoration. Used to treat contaminated media including water, soil & subsurface material by altering environmental condition to stimulate growth of microorganism & degrade the target pollutants.

3. Bioremediation is a triple corner process

4. TYPES The environmental cleanup procedure through bioremediation can be achieved in 2 ways: In situ bioremediation Ex situ bioremediation

5. In situ Bioremediation Involves a direct approach for the microbial degradation of xenobiotics at the site of pollution. Addition of adequate quantities of nutrients at the site promotes microbial growth. When these microorganisms are exposed to xenobiotics , they develop metabolic ability to degrade them. The growth of microorganisms & their ability to bring out biodegradation are dependent on the supply of essential nutrients. In situ bioremediation has been successfully applied for cleanup of oil spillages, beaches etc.

6. There are 2 types of in situ bioremediation Intrinsic in-situ bioremediation Engineered in-situ bioremediation Intrinsic in-situ bioremediation I nherent metabolic ability of the microorganism to degrade certain pollutants . Engineered in-situ bioremediation Inherent ability of microorganisms for biodegradation is generally slow & limited. However by using suitable physico - chemical means, bioremediation process can be engineered for more efficient degradation of pollutants.

7. Ex situ Bioremediation The waste or toxic materials can be collected from polluted sites & the bioremediation with the requisite microorganism can be carried out at designed places. This process is certainly an improvement over in-situ bioremediation & has been successfully used at some places. Ex-situ bioremediation can occur in 2 ways Slurry phase bioremediation Solid phase bioremediation

8. 1. Slurry phase bioremediation Contaminated soil is mixed with water & other reagents in larger tank (bioreactor). Oxygen & nutrients are added into the mix, so microorganism can have ideal environment to break down contaminants. Once the process is complete, water is separated from the soil. Soil is tested & replaced in the environment .

9. 2. Solid phase bioremediation Treats contaminated soil in an above ground treatment centre. Conditions are controlled to ensure optimum treatment can take place. Is easy to maintain but requires a lot of space & process of decontamination takes longer. It includes land farming, soil bio-piles & composting.

10. IN-SITU BIOREMEDIATION EX-SITU BIOREMEDIATION ADVANTAGES Cost effective Minimal exposure to public/site personnel Site of bioremediation remains minimally disrupted. ADVANTAGES Better controlled More efficient process Time required is short Process can be improved by enrichment with desired microorganism DISADVANTAGES Time consuming Sites are directly exposed to environmental factors Microbial degrading ability varies seasonally. DISADVANTAGES Very costly process. Sites of pollution are highly disturbed. There may be disposal problem after the process is complete.

11. EVALUATING BIOREMEDIATION Performance evaluation of bioremediation, especially in-situ bioremediation in the field is difficult due to, Uncertainity created by the matrix Contaminant heterogenity Inaccessibility to observation Expense of sampling Limitation of some measurements

12. 4 key pieces of evidence indicative of successful bioremediation are: Documentation of loss of phenanthrene An increase in aqueous phase TIC Decrease in δ¹³ carbon of dissolved organic pool A correlation b/w the phenanthrene removal & increase in number of phenanthrene degrading bacteria .

13. BIOREMEDIATION OF VOLATILE ORGANIC COMPOUNDS Volatile organic compounds(VOCs) are major air pollutants which are released into the environment through mobile sources, stationary sources, area sources & natural sources. Various organisms that can degrade VOCs have been reported. However, the biodegradation of VOCs remains a challenging issue. Practical sites such as chemical factories, research facilities & illegal dumping sites are often contaminated with multiple VOCs. VOCs include chlorinated ethenes , BTEX & chlorinated methane.

14. Based on the concentration level of VOC, several removal technique have been employed to combat VOCs. Non biological methods such as ozonation , absorption, adsorption, incineration, condensation, membrane seperation are being employed. Several biological methods ranging from trickling filters to biofilters have been demonstrated & they are found to be economical. The biofilters are simple to construct, easy to operate & cost effective.

15. Thank you