A Recent Technique for Contaminated Soils: Bioremediation

1. A Recent Technique for Contaminated Soils:Bioremediation Kaan Poyraz Civil Engineering – Environmental Engineering

2. Bioremediation • Bioremediation can be defined as any process that uses microorganisms, fungi, green plants or their enzymes to return the natural environment altered by contaminants to its original condition.

3. Bioremediation • Cleanup of oil spills by the addition of nitrate and/or sulfate fertilizers to facilitate the decomposition of crude oil by indigenous or exogenous bacteria. • To attack specific soil contaminants, such as degradation of chlorinated hydrocarbons by bacteria.

5. Overview and applications • Naturally occurring bioremediation and phytoremediation have been used for centuries (desalination of agricultural land by phytoextraction). • Bioremediation technology using microorganisms was reportedly invented by George M. Robinson. He was the assistant county petroleum engineer for Santa Maria, California. During the 1960s, he spent his spare time experimenting with dirty jars and various mixes of microbes.

6. Overview and applications • Bioremediation 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 technologies are bioventing, landfarming, bioreactor, composting, bioaugmentation, rhizofiltration, and biostimulation.

8. Overview and applications • Naturally occurring bioremediation: natural attenuation or intrinsic bioremediation • Bioremediation via the addition of fertilizers to increase the bioavailability within the medium: biostimulation • Addition of matched microbe strains to the medium to enhance the resident microbe population's ability to break down contaminants: bioaugmentation

9. Overview and applications • Heavy metals such as cadmium and lead are not readily absorbed or captured by organisms. The assimilation of metals such as mercury into the food chain may worsen matters. • Phytoremediation is useful in these situations, because natural plants or transgenic plants are able to bioaccumulate these toxins in their above-ground parts, which are then harvested for removal.

12. Advantages • the cost of the phytoremediation is lower than that of traditional processes both in situ and ex situ • can be employed in areas that are inaccessible without excavation • the plants can be easily monitored • the possibility of the recovery and re-use of valuable metals (by companies specializing in “phyto mining”) • it is potentially “the least harmful” method because it uses naturally occurring organisms and preserves the environment in a more natural state

13. References • http://www.terranovabiosystems.com/science/remediation-resources.html • http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V24-4DVBJ2S-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1008717983&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=8fded7c6e7043ef8d478fe757de76f02 • Meagher, RB (2000). "Phytoremediation of toxic elemental and organic pollutants". Current Opinion in Plant Biology3 (2): 153–162. doi:10.1016/S1369-5266(99)00054-0. PMID 10712958. • Diaz E (editor). (2008). Microbial Biodegradation: Genomics and Molecular Biology (1st ed.). Caister Academic Press. ISBN 978-1-904455-17-2. • http://www.horizonpress.com/biod.  • Lovley, DR (2003). "Cleaning up with genomics: applying molecular biology to bioremediation". Nature Reviews. Microbiology.1 (1): 35 – 44. doi:10.1038/nrmicro731. PMID 15040178. • Brim H, McFarlan SC, Fredrickson JK, Minton KW, Zhai M, Wackett LP, Daly MJ (2000). "Engineering Deinococcusradiodurans for metal remediation in radioactive mixed waste environments". Nature Biotechnology18 (1): 85 – 90. doi:10.1038/71986. PMID 10625398.

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