United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
EPA/542/F-92/008
March 1992
ŁEPA
A Citizen's Guide To
Bioventing
Technology Innovation Office.
.Technology Fact Sheet
CONTENTS
Page
What Is Bioventing? 1
What Is
Bioremedlatlon?
How Does
Bioventing Work?
Why Consider
Bioventing?
Will Bioventing
Work At Every Site? 2
Where Is Bioventing
Being Selected? 3
For More Information
What Is Bioventing?
Bioventing is an in situ (in place)
process of injecting air into
contaminated soil at rates low
enough to increase soil oxygen
concentrations and stimulate
indigenous (native) microbial
activity.
Bioventing is one of several
bioremediation technologies and
makes use of a naturally occurring
process. Microorganisms multiply
when food and oxygen sources are
abundant and they decrease in
number when the contaminant is
degraded.
What Is Bioremediation?
Bioremediation uses naturally
occurring microorganisms (bacteria,
yeast, and/or fungi) to degrade —
break down— hazardous substances
into less toxic or nontoxic
substances. Microorganisms, just
like humans, use organic substances
for nutrients and energy. Certain
microorganisms can digest organic
substances that are hazardous to
humans. Some organic
contaminants can be degraded into
harmless products consisting mainly
of carbon dioxide and water. Some
examples of organic contaminants
that microorganisms can degrade
include fuels, such as oil spills, and
solvents.
Microorganisms must thrive at the
site in order for bioremediation to
take place. In addition to the food
source provided by the organic
contaminants, microorganisms
require nutrients. Microorganisms
that require oxygen to survive are
called aerobic microorganisms.
Those that do not require oxygen are
called anaerobic microorganisms.
The specific bioremediation
technology used is determined by
the type of microorganisms present,
site conditions (such as nutrient and
Bioventing Profile
Bioventing Is a process of Injecting air Into contaminated soil at rates that Increase soli oxygen
concentrations and stimulate microbial activity.
Bioventing Is most effective on organic contaminants, such as fuels and solvents.
U.S. Environmental Protection
Bioventing is an in situ technology that Is conducted on-slte. Region 5, Library (PI 1 ? ft
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oxygen levels), and geological factors. For example, if
aerobic microorganisms are present at a given site and
if the amount of oxygen available to them is limited,
then bioventing would be an appropriate way to
enhance bioremediation at this site.
How Does Bioventing Work?
Figure 1 illustrates the bioventing process. It begins
by drilling injection wells into the ground where the
contamination exists. The number, location, and depth
of the wells depends on many geological factors and
engineering considerations.
An air blower delivers air from the atmosphere into the
contaminated soil through the injection wells. Air
(containing oxygen) flows through the soil and is used
by the microorganisms. In addition to oxygen, other
nutrients may be pumped into the soil through the
injection wells. For example, nitrogen and
phosphorous may be pumped in amounts appropriate
for optimizing the growth of microorganisms. The
microorganisms will use the contaminants in the soil
as a food source and convert them to nonhazardous
substances. The main end products of this conversion
reaction are carbon dioxide and water.
The level of these end products is monitored to see if
the bioremediation reaction is indeed occurring. If it is
not, factors such as nutrient and oxygen levels in the
soil may need adjusting.
Figure 1
Bioventing
Surface
Monitoring
To Assure No
VOC Emissions
Extraction
Wall
(Option*!)
Equipment For
Monitoring Tli*
UvdOfEnd
Product*
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sites where additional oxygen would help the
microorganisms thrive.
Bioventing is most effective on the unsaturated soil
above the water table. Since bioventing pushes air
through the soil, it is used on porous soil in the
unsaturated zone.
Where Is Bioventing Being Selected?
Bioventing has been selected as a treatment method
for the Cliff/Dow Dump Superfund site in Michigan.
This site contains waste disposal from a charcoal
manufacturing plant. Bioventing is also being used for
jet fuel clean-up at several demonstration sites,
including Tyndall Air Force Base in Florida, Eielson
Air Force Base near Fairbanks, Alaska and Hill Air
Force Base, just north of Salt Lake City, Utah.
What is An Innovative Treatment
Technology?
Treatment technologies 'are processes applied
to the treatment of hazardous waste or
contaminated material* to permanently alter
their condition through chemical, biological, or
physical means. Technologies that have been
tested, selected or used for treatment of
hazardous waste or contaminated materials but
lack well-documented cost and performance
date under a variety of operating conditions are
called Innovative treatment technologies.
For More information
EPA prepared this fact sheet to provide basic information on bioventing. Additional technical reports are
listed below. The documents containing a "PB" designation are available by contacting the National Techni-
cal Information service (NTJS) at 1-800-336-4700. Mall order* can be sent to:
National Technical Information Service
Springfield, VA 22161
Other documents may be obtained by contacting:
Center for Environmental Research Information
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513)569-7562
There may be a charge for these documents.
• Understanding Bloremediation: A Guide Book for Citizens, EPA/540/2-91/002.
• Bloremediation In the Field, EPA/540/2-91/027.
• Bloremediation of Contaminated Surface Soil, PB90-164047.
• In-SItu Bloremediatlon of Spills From Underground Storage Tanks, PB89-219976.
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77_West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
NOTICE: This fact sheet is intended solely as general guidance and information. It is not intended, nor can it be relied upon, to create any rights enforceable by any
party in litigation with the United States. The Agency also reserves the right to change this guidance at any time without public notice.
•U.S. Government Printing Office: 1992— 648-080/60008
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