Bioremediation

Bioremediation can be defined as any process that uses fertilisers to facilitate the decomposition of crude oil by indigenous or exogenous bacteria.

Overview and applications

Naturally-occurring bioremediation and phytoremediation have been used for centuries. For example, desalination of agricultural land by phytoextraction has a long tradition. Bioremediation technology using microorganisms was reportedly 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.

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, composting, bioaugmentation, rhizofiltration, and biostimulation.

Not all contaminants, however, are easily treated by bioremediation using microorganisms. For example, bioaccumulate these toxins in their above-ground parts, which are then harvested for removal^[1]. The heavy metals in the harvested biomass may be further concentrated by incineration or even recycled for industrial use.

Microbial Biodegradation

Interest in the microorganisms providing unprecedented insights into key biodegradative pathways and the ability of organisms to adapt to changing environmental conditions.

The elimination of a wide range of pollutants and wastes from the environment is an absolute requirement to promote a sustainable development of our society with low environmental impact.^{[citation needed]} Biological processes play a major role in the removal of contaminants and they take advantage of the astonishing catabolic versatility of microorganisms to degrade/convert such compounds. New methodological breakthroughs in biotransformation processes.^[2]

Genetic engineering approaches

The use of genetic engineering to create organisms specifically designed for bioremediation has great potential.^[3] The bacterium mercury from highly radioactive nuclear waste.^[4]

Advantages

There are a number of cost/efficiency advantages to bioremediation, which can be employed in areas that are inaccessible without excavation. For example, concentrations after a lag 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 common practice at sites where hydrocarbons have contaminated groundwater.

Monitoring bioremediation

The process of bioremediation can be monitored indirectly by measuring the Oxidation Reduction Potential or 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.

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 is that electron acceptors have been used up, it's 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.

See also

• Biodegradation
• Dutch standards
• List of environment topics
• Phytoremediation
• Mycoremediation
• Living machines
• Intrinsic bioremediation
• US Microbics
• Microbial biodegradation

References