Bioremediation

Bioremediation

Mechanism of salt removal from tsunami affected soil by bioremediation

Bioremediation is a waste management technique that involves the use of organisms to remove or neutralize pollutants from a contaminated site.[1] 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”. Technologies can be generally classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site, while ex situ involves the removal of the contaminated material to be treated elsewhere. Some examples of bioremediation related technologies are phytoremediation, bioventing, bioleaching, landfarming, bioreactor, composting, bioaugmentation, rhizofiltration, and biostimulation.

Bioremediation may occur on its own (natural attenuation or intrinsic bioremediation) or may only effectively occur through the addition of fertilizers, oxygen, etc., that help encourage the growth of the pollution-eating microbes within the medium (biostimulation). For example, the

  • hosted by the Missouri Botanical GardenPhytoremediation Website
  • Toxic cadmium ions removal by isolated fungal strain from e-waste recycling facility (Kumar et al., 2012)
  • Removal of Cu2+ Ions from Aqueous Solutions Using Copper Resistant Bacteria (Rajeshkumar and Kartic 2011)

External links

  1. ^ http://ei.cornell.edu/biodeg/bioremed/
  2. ^ Mann, D. K., T. M. Hurt, E. Malkos, J. Sims, S. Twait and G. Wachter. 1996. Onsite treatment of petroleum, oil, and lubricant (POL)-contaminated soils at Illinois Corps of Engineers lake sites. US Army Corps of Engineers Technical Report No. A862603 (71pages).
  3. ^ Sims, G.K. (2006). "Nitrogen Starvation Promotes Biodegradation of N-Heterocyclic Compounds in Soil". Soil Biology & Biochemistry 38: 2478–2480.  
  4. ^ O'Loughlin, E. J; Traina, S. J.; Sims, G. K. (2000). "Effects of sorption on the biodegradation of 2-methylpyridine in aqueous suspensions of reference clay minerals". Environ. Toxicol. and Chem 19: 2168–2174.  
  5. ^ Kris S. Freeman (January 2012). "Remediating Soil Lead with Fishbones". Environmental Health Perspectives. 
  6. ^ http://coastguard.dodlive.mil/2012/07/battling-lead-contamination-one-fish-bone-at-a-time/
  7. ^ Huan Jing Ke Xue (February 2007). "Chemical fixation of metals in soil using bone char and assessment of the soil genotoxicity". 
  8. ^ Meagher, RB (2000). "Phytoremediation of toxic elemental and organic pollutants". Current Opinion in Plant Biology 3 (2): 153–162.  
  9. ^ Francesca Cappitelli; Claudia Sorlini (2008). "Microorganisms Attack Synthetic Polymers in Items Representing Our Cultural Heritage". Applied Environmental Microbiology 74: 564–9.  
  10. ^ Olapade, OA; Ronk, AJ (2014). "Isolation, Characterization and Community Diversity of Indigenous Putative Toluene-Degrading Bacterial Populations with Catechol-2,3-Dioxygenase Genes in Contaminated Soils". Microbial Ecology 69: 59–65.  
  11. ^ Diaz E (editor). (2008). Microbial Biodegradation: Genomics and Molecular Biology (1st ed.). Caister Academic Press.  
  12. ^ Lovley, DR (2003). "Cleaning up with genomics: applying molecular biology to bioremediation". Nature Reviews Microbiology 1 (1): 35–44.  
  13. ^ Brim H, McFarlan SC, Fredrickson JK, Minton KW, Zhai M, Wackett LP, Daly MJ (2000). "Engineering Deinococcus radiodurans for metal remediation in radioactive mixed waste environments". Nature Biotechnology 18 (1): 85–90.  
  14. ^ Robert L. Irvine; Subhas K. Sikdar. Bioremediation Technologies: Principles and Practice. 
  15. ^ "Biodegradation of Polyester Polyurethane by Endophytic Fungi". Applied and Environmental Microbiology. July 2011. 
  16. ^ "Archaea Effectiveness, Benefits - Akaya". Akaya. Retrieved 2015-09-10. 
  17. ^ "Developments in Bioremediation of Soils and Sediments Polluted with Metals and Radionuclides – 1. Microbial Processes and Mechanisms Affecting Bioremediation of Metal Contamination and Influencing Metal Toxicity and Transport". Reviews in Environmental Science and Bio/Technology 4: 115–156. August 2005.  
  18. ^ "Bioremediation of contaminated marine sediments can enhance metal mobility due to changes of bacterial diversity". Water Research. January 2015. 

References

See also

  1. It is necessary to sample enough points on and around the contaminated site to be able to determine contours of equal redox potential. Contouring is usually done using specialised software, e.g. using Kriging interpolation.
  2. If all the measurements of redox potential show that electron acceptors have been used up, it is in effect an indicator for total microbial activity. Chemical analysis is also required to determine when the levels of contaminants and their breakdown products have been reduced to below regulatory limits.
  3. Chemical analysis should also be carried out for assessing transformations in inorganic contaminants (e.g. [18] bioremediation.in-situ. An increase in heavy metal mobility can occur, even in reductive conditions, during bio-availability and remediation processes can both increase and decrease their solubility and [17]

This, by itself and at a single site, gives little information about the process of remediation.

Process Reaction Redox potential (Eh in mV
aerobic O2 + 4e + 4H+ → 2H2O 600 ~ 400
anaerobic
denitrification 2NO3 + 10e + 12H+ → N2 + 6H2O 500 ~ 200
manganese IV reduction MnO2 + 2e + 4H+ → Mn2+ + 2H2O     400 ~ 200
iron III reduction Fe(OH)3 + e + 3H+ → Fe2+ + 3H2O 300 ~ 100
sulfate reduction SO42− + 8e +10 H+ → H2S + 4H2O 0 ~ −150
fermentation 2CH2O → CO2 + CH4 −150 ~ −220

The process of bioremediation can be monitored indirectly by measuring the Oxidation Reduction Potential or redox in soil and groundwater, together with pH, temperature, oxygen content, electron acceptor/donor concentrations, and concentration of breakdown products (e.g. carbon dioxide). This table shows the (decreasing) biological breakdown rate as function of the redox potential.

Monitoring bioremediation

There are a number of cost/efficiency advantages to bioremediation, which can be employed in areas that are inaccessible without excavation. For example, hydrocarbon spills (specifically, petrol spills) or certain chlorinated solvents may contaminate groundwater, and introducing the appropriate electron acceptor or electron donor amendment, as appropriate, may significantly reduce contaminant concentrations after a long time allowing for acclimation. This is typically much less expensive than excavation followed by disposal elsewhere, incineration or other ex situ treatment strategies, and reduces or eliminates the need for "pump and treat", a practice common at sites where hydrocarbons have contaminated clean groundwater. Using archaea for bioremediation of hydrocarbons also has the advantage of breaking down contaminants at the molecular level, as opposed to simply chemically dispersing the contaminant.[16]

Advantages

microorganisms from water in soil.

Two species of the Ecuadorian fungus Pestalotiopsis are capable of consuming Polyurethane in aerobic and anaerobic conditions such as found at the bottom of landfills.[15]

In one conducted experiment, a plot of soil contaminated with diesel oil was inoculated with mycelia of oyster mushrooms; traditional bioremediation techniques (bacteria) were used on control plots. After four weeks, more than 95% of many of the PAH (polycyclic aromatic hydrocarbons) had been reduced to non-toxic components in the mycelial-inoculated plots. It appears that the natural microbial community participates with the fungi to break down contaminants, eventually into carbon dioxide and water. Wood-degrading fungi are particularly effective in breaking down aromatic pollutants (toxic components of petroleum), as well as chlorinated compounds (certain persistent pesticides; Battelle, 2000).

One of the primary roles of nerve gases VX and sarin.

Mycoremediation is a form of bioremediation in which fungi are used to decontaminate the area. The term mycoremediation refers specifically to the use of fungal mycelia in bioremediation.

Mycoremediation

:135 [14] The use of

Genetic engineering approaches

Contents

  • Genetic engineering approaches 1
  • Mycoremediation 2
  • Advantages 3
  • Monitoring bioremediation 4
  • See also 5
  • References 6
  • External links 7

The elimination of a wide range of pollutants and wastes from the environment requires increasing our understanding of the relative importance of different pathways and regulatory networks to carbon flux in particular environments and for particular compounds, and they will certainly accelerate the development of bioremediation technologies and biotransformation processes.[11]

[10] In contrast to this situation, other contaminants, such as aromatic hydrocarbons as are common in petroleum, are relatively simple targets for microbial degradation, and some soils may even have some capacity to autoremediate, as it were, owing to the presence of autochthonous microbial communities capable of degrading these compounds.[9] The heavy metals in the harvested biomass may be further concentrated by incineration or even recycled for industrial use. Some damaged artifacts at museums contain microbes which could be specified as bio remediating agents.[8] these toxins in their above-ground parts, which are then harvested for removal.bioaccumulate are able to transgenic plants is useful in these circumstances because natural plants or Phytoremediation may worsen matters. food chain into the mercury The assimilation of metals such as [7].zinc, and copper, cadmium Bone char has been shown to bioremediate small amounts of [6][5] However, not all contaminants are easily treated by bioremediation using microorganisms. For example,

. bioremediators Recent advancements have also proven successful via the addition of matched microbe strains to the medium to enhance the resident microbe population's ability to break down contaminants. Microorganisms used to perform the function of bioremediation are known as [4] of the chemicals to microbes.bioavailability and soil materials with a high capacity to adsorb pollutants may slow down biodegradation owing to limited [3]