Quiz 9: Bioremediation
Bioremediation can be well-defined, as a procedure that takes the use of microbes or the enzymes produced to treat the contaminated environment. Bioremediation can be applied to certain specific pollutants, like chlorinated pesticides, which can be destroyed the bacteria. A broad approach can be used, for the treatment of polluted oil spills. They can be wrecked down through multiple techniques that may include adding of fertilizer to assist the putrefaction of crude oil, via bacteria. In general, technologies of bioremediation can be categorized as: in situ and ex situ. • In situ method of bioremediation comprises the treatment of the contaminated area at the site only. • Ex situ method of bioremediation comprises the exclusion of the contaminated substances from the area and to be administered elsewhere. Few examples, of bioremediation technologies include land farming, composting, bioventing, bioreactor, bioaugmentation and biostimulation. Examples of bioremediation include: a) An enzyme produced by the bacterium Thermus brockianus was established in Yellowstone National Park. This enzyme halts down hydrogen peroxide into water and oxygen about 80,000 times faster than any chemicals currently in use. b) Some plants can be used, for treatment. The process is called phytoremediation. Alfalfa share symbiotic relationship with hydrocarbon reducing bacteria. c) Genetically modified bacteria Deinococcus radiodurans have been in use to digest heavy metals and diluents. It is used, for the digestion of ionic mercury and toluene obtained from extremely radioactive nuclear waste. Advantages of bioremediation are: • It works well on a number of organic, as well as inorganic compounds. • It can be performed either on the site itself or off-site also. • It is relatively easy to apply and sustain. • It involves low cost in comparison with other methods of treatment. • It is environment friendly and visually attractive also. • It reduces the quantity of wastes present in landfilled Disadvantages of bioremediation are: • It takes several years, for the completion of the process. • Its outcome depends on the prevailing climatic conditions. • It is constrained to the sites that are contaminated near the pedigrees. • The plants harvested on the treated land would be classified, as harmful waste. • It may be possible that it would put hazardous effect on the food chain.
Bioremediation can be well-defined, as a procedure that takes the use of microbes or the enzymes produced to treat the contaminated environment. Bioremediation can be applied in order to attack certain specific pollutants, like chlorinated pesticides that are destroyed by bacteria. A broad approach can be used, for the treatment of polluted oil spills. They can be wrecked down through multiple techniques that may include adding of fertilizer to assist the putrefaction of crude oil via bacteria. In general, technologies of bioremediation can be categorized as in situ and ex situ. • In situ method of bioremediation comprises the treatment of the contaminated area at the site only. • Ex situ method of bioremediation comprises the exclusion of the contaminated substances from the area and to be administered elsewhere. Few examples of bioremediation technologies include land farming, composting, bioventing, bioreactor, bioaugmentation, and biostimulation. In situ method of bioremediation is usually favored over ex situ approach. It is because of the following reasons: • In situ approach is less expensive. • In the in situ approach, there is no need of excavation of soil or water from the original site. • Greater areas of the contaminated soil can be administered at one time. The outcomes of the in situ approaches depend on the stimulating microbes added in the polluted soil and water. a) Certain in situ approaches include, method of aerobic degradation usually comprising of bioventing. It includes impelling of either hydrogen peroxide or air into the polluted soil. Hydrogen peroxide is normally preferred, as it certainly breaks down into water and oxygen to offer microbes, as a source of oxygen. Oxygen helps in the oxidation of number of organic compounds, and reduces to water. b) Microorganisms surviving in that area can help in the degradation of oxidized organic compounds. They require carbon, hydrogen, oxygen, nitrogen, and phosphorous, for the production of macromolecules. Fertilizers can be added into the soil by bioventing to encourage the development and degradation actions of these indigenous bacteria. It is called nutrient enrichment.
Most of the contaminated sites existing all over the United States are under reconstruction, for the purpose of industries and residents. Houses established on these contaminated areas are sometimes sold at relatively lower prices than other homes of similar area, but prepared at fresh sites. It is not essential, for the builders in all the states to reveal the real history of the land to the prospective home buyers. The problems associated with these sites are: • It may be possible that the site may not be completely hygienic, for the purpose of living. • The housing communities that depend on the groundwater, for supplying the drinking water need to do a regular monitoring, for the concentration of chemical pollutant present in it. • This could be very challenging. It is because trace quantities of some of the chemicals might go unnoticed, and they may accumulate in the body. Thus, initially the effect of these toxins might go undetected. Later they may come up with severe disease. • Correspondingly, the remnant chemicals in the soil would put impact on the residents' activities, for instance, the plants grown in the soil would be affected, and children playing in the lawns may also take the chemicals. • A foremost problem regarding bioremediated sites used, for residential purpose is that it might take several years to conclude if dwellers are undergoing any health problems from the leftover chemicals or not. • Even when inhabitants would experience any health related problems, it is very tough to decide, whether these effects are really because of the pollutants present at the site.
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