Information AboutBioremediation |
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Not all contaminants are easily treated through the use of bioremediation; for example, Heavy Metals such as Cadmium and Lead are not readily absorbed or captured by organisms. The integration of metals such as Mercury into the Food Chain may make things worse as organisms Bioaccumulate these metals. However, there are a number of advantages to bioremediation, which may be employed in areas that cannot be reached easily without Excavation . For example, Hydrocarbon spills (specifically, Petrol spills) or certain chlorinated solvents may contaminate Groundwater in the subsurface and introducing the appropriate electron acceptor or electron donor amendment, as appropriate, may significantly reduce contaminant Concentration s after a period of time. This is typically much less expensive than excavation followed by disposal elsewhere, Incineration or other ''ex situ'' treatment, and reduces or eliminates the need for and treat , a common practice at sites where hydrocarbons have contaminated groundwater. Generally, bioremediation technologies can be 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 . Bioremediation was invented by George M. Robinson . He was the assistant county petroleum engineer for Santa Maria California. During the 1960's he spent his spare time experimenting with dirty jars and various mixes of microbes. MONITORING BIOREMEDIATION 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.
This, by itself and at a single site, gives little information about the process of Remediation . # 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. # if all the measurements of redox potential show is that electron acceptors have been used up, it's in effect an Indicator for total microbial activity. Chemical analysis is also required in order to demonstrate that levels of hydrocarbons and breakdown products have been reduced by remediation to below regulatory limits. SEE ALSO
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