Biodegradation is a pollution treatment method that uses micro-organisms to break down contaminants. Microorganisms can be bacteria, fungi or other organisms that feed on the organic matter present in pollutants.
Biodegradation is often used to clean up sites polluted by hydrocarbons such as oil, solvents, pesticides and organic chemicals. This method can be carried out either in situ, on site, or ex situ, off site.
In situ biodegradation is achieved by injecting nutrients into the soil to stimulate the growth of degrading microorganisms. This method is often used when pollutants are in high concentration in the soil and the site is too large or too difficult to access for excavation.
Ex situ biodegradation is achieved by removing polluted soil from the site and placing it in bioreactors, where micro-organisms can degrade contaminants in a controlled environment. This method is often used when pollutants are present in very high concentrations and in situ biodegradation is not viable.
The advantages of biodegradation are that it is less invasive and more environmentally friendly than other pollution treatment methods. Biodegradation is also often less costly than other methods, such as excavation and off-site transportation of polluted soils.
For in-situ remediation, other treatment methods include controlled natural attenuation, biosparging, thermal desorption, dual-phase extraction, flushing, chemical oxidation, pump-and-skim, pump-and-treat, chemical reduction, sparging and venting.