United States
                       Environmental Protection
                                                   Office of
                                                   Solid Waste and
                                                   Emergency Response
                March 1992
                       A  Citizen's Guide  To
Technology Innovation Office.
                                                                    .Technology Fact Sheet


 What Is Bioventing?    1
 What Is
 How Does
 Bioventing Work?
 Why Consider
 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

                             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

                             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

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
     _,	^^^st Jackson Boulevard,  l?th FI
 Produced by the
Superfund Program
                                                                        Printed on Recycled Paper

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
                                    To Assure No
                                    VOC Emissions
           Equipment For
           Monitoring Tli*
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

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

    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