Bioventing

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== Principle ==
== Principle ==
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Bioventing is an in-situ [[bioremediation]] process that promotes [[aerobic]] biodegradation of organic contaminants in the unsaturated (vadose) zone. The method is suitable for sites contaminated with fuel compunds like gasoline, diesel and jet fuel as well as other biodegradable chemicals. Typically, these pollutants will be biodegraded at aerobic conditions by indigenous heterotrophic [[microorganism]]s naturally occurring in the soil. Thus, in order to promote microbial degradation, air or poor oxygen is delivered to anaerobic and permeable polluted soil zones at a low flow rate such that the oxygen supply rate meets the demand by the microorganisms and minimizes volatilization of volatile contaminants.
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Bioventing is an in-situ [[bioremediation]] process that promotes [[aerobic]] biodegradation of organic contaminants in the unsaturated (vadose) zone. The method is suitable for sites contaminated with fuel compunds like gasoline, diesel and jet fuel as well as other biodegradable chemicals. Typically, these pollutants will be biodegraded at aerobic conditions by indigenous heterotrophic [[microorganism]]s naturally occurring in the soil. Thus, in order to promote microbial degradation, air or poor oxygen is delivered to [[anaerobic]] and permeable polluted soil zones at a low flow rate such that the oxygen supply rate meets the demand by the microorganisms and minimizes volatilization of volatile contaminants.
[[Image:Biofinal2.gif]]
[[Image:Biofinal2.gif]]

Revision as of 18:25, 2 March 2008

Bioventing belongs to the bioremediation technologies. Additional examples of bioremediation approaches include landfarming, bioaugmentation, biostimulation, and biosparging.

Contents

Principle

Bioventing is an in-situ bioremediation process that promotes aerobic biodegradation of organic contaminants in the unsaturated (vadose) zone. The method is suitable for sites contaminated with fuel compunds like gasoline, diesel and jet fuel as well as other biodegradable chemicals. Typically, these pollutants will be biodegraded at aerobic conditions by indigenous heterotrophic microorganisms naturally occurring in the soil. Thus, in order to promote microbial degradation, air or poor oxygen is delivered to anaerobic and permeable polluted soil zones at a low flow rate such that the oxygen supply rate meets the demand by the microorganisms and minimizes volatilization of volatile contaminants. Image:Biofinal2.gif


Applicability

Prior to onset of bioventing, it is recommended to perform tests and measurements. These should include an in situ respiration test, an in situ air permeability test and measurements of pH, bioavailable nutrients and soil moisture. Furthermore, it is relevant to carry out batch or column biodegradation experiments in the laboratory using the contaminant in question. This will provide information about specific degradation rates.

Bioventing is not recommended in case of limiting air transport conditions (fine texture or saturated layers) or inhibited bioactivity (extreme pH, oligotrophic environment etc.)


Supplementing technologies

Bioventing is often combined with vacuum extraction in order to control the transport of the injected air. Furthermore, biostimulation using addition of nutrients can be applied. However, infiltration of dissolved nutrients may increase moisture content in the unsaturated zone, leading to inhanced gas transport properties.


External links:

Overview (USEPA)

A Guide for Corrective Action Plan Reviewers (USEPA)

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