United States
Environmental Protection
Agency
Office of Research and
Development
Washington, DC 20460
Office of Solid Waste and
Emergency Response
Washington, DC 2O46O
&EPA
SITE FACTS
**; ocation: Fairbanks, Alaska? ' -
«. */ "* *" ^ * ^ "v» *^>? i*V:l'! '
'- Laboratories/Agencies: U.S.
J- *Afi Force, U.SrEPARisk ',
' Reduction Engineering ,, > „>"
*: Laboratory (RREL), U.S. EPA '„ '<
^Region 10 _ ,' ' , ' "',,,*,.//
Media and Contaminants: <
^ < -, ( , > ' -
* , Treatment: Bioventing'with " < ' '
' active arid passive isoil warming „•
Date of Initiative Selection:
r Spring 1991 *,' '',.'; * '' :
I* Objective: To examine the jise" ~t ~,
* 4trf soil-warming technologies to, %•
*^enhance theeffectiyeness of J .
? ated soil in a cold climate -
tt ^.^ i ,,-f , ,•<„ -,, , ,
d Bioremediation Field Initiative
f^\Contact: Greg Sayles,U.S. E?X
";SJRREL, 26 West Martin Luther , ,' > ,
» sKing Drive, Cincinna,ti, OH t
'- 45268 _ 7 . - , ' / ^ / _
\ Regional Contact:, Mary Jane ,
' "Tvfearman^UiS'.'EPARegiOn'lO;" ' "•
(^ 1200 SixttvAvenue7 "4"
*''
EPA/540/F-93/510B
September 1993
Bioremediation Field
Initiative Site Profile:
Eielson Air Force Base
Superfund Site
Background
Eielson Air Force Base (AFB) in Fairbanks, Alaska, is one of approxi-
mately 4,300 Air Force sites contaminated with petroleum hydrocar-
bons in soil. The Air Force currently is implementing an extensive
program to examine the use of bioventing to remediate many of these
sites. This program was developed based on preliminary results from
Eielson and Hill AFBs, where the Air Force and the U.S. EPA Risk
Reduction Engineering Laboratory (RREL) are conducting joint field
evaluations of bioventing. (Activities at Hill AFB are summarized in
a separate fact sheet.) The results from Eielson AFB will help deter-
mine whether bioventing can be pursued at other cold-climate sites in
the northern United States.
Characterization
The soil at the Eielson site is a mixture of sand and silt contaminated
with JP-4 jet fuel from a depth of roughly 2 ft to the water table at 6 to
7 ft. Prior to bioventing, hydrocarbon concentrations in the soil gas
ranged from 600 to 40,000 mg/kg. Although the site is not in the
permafrost region, soil temperatures in winter drop to nearly 0°C.
Researchers believe that using soil-warming measures to promote
high-rate, year-round bioremediation will cost less overall than sus-
taining low-rate bioremediation at ambient temperatures for an ex-
tended period of time.
Field Evaluation
A 1-acre contaminated area was divided into three 50-ft square seg-
ments (see Figure 1). One plot, which receives bioventing without
heating, serves as a control. The two other plots each undergo one of
the following soil-warming techniques:
Passive warming. Plastic covering (mulch) is used to enhance solar
warming in late spring, summer, and early fall. During the remainder
of the year, heat is retained by applying insulation to the surface.
Active warming. Ground water is circulated to an electric heater, heated
to 35°C, and reinjected below the ground surface to the contaminated
soil. The heated water is applied at a very low rate (1 gpm) by five
T^X Printed on paper that contains at least
Sa£y 50 percent recycled fiber.
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Passive;
Control
\
N
Site Trailer
Active Warming System
@) - Ground water monitoring well
O -Air injection/withdrawal well •
^ - Three-level soil gas probe
• -Three-level thermocouple probe
25' 50'
Scale
Figure 1. Plan view of actively heated, passively heated, and un-
heated plots.
soaker hoses, placed 2 ft below the surface. The
surface is covered with insulation year round.
The passive warming system is being operated by
the Air Force (see Figure 2). KREL is operating the
active warming system. Air injection/withdrawal
^^
Figure 2. Passively heated plot covered with insulation.
wells are distributed uniformly at 30-ft intervals
among the three plots. Air is injected to each well
at a rate of 2.5 ftVmin, providing the plots with
relatively uniform aeration. Three-level gas moni-
toring wells and three-level temperature probes are
distributed throughout the site.
In situ respirometry tests are conducted peri-
odically to measure the in situ rate of oxygen up-
take by the microorganisms. During these tests,
researchers shut off air injection for 4 to 8 days and
monitor the soil gas oxygen concentration over
time. The decrease in oxygen concentration, less
that observed in a background area, indicates the
rate of biodegradation in the contaminated soil.
Status
Researchers began venting air and trickling un-
heated water to the actively warmed plot in Sep-
tember 1991. Warming of the water began in
October 1991. In January 1992, researchers deter-
mined that all three plots were aerated adequately,
with soil gas oxygen levels ranging from 12 to 20
percent. The temperature remained above 10°C in
the actively warmed plot, while temperatures in
the passively warmed plot and the control plot
dropped to near 0°C. Measured biodegradation
rates were twice as high in the actively warmed
area as they were in the control. Furthermore, -the
degradation rate of 2.9 mg/kg/day in the actively
warmed plot is comparable to rates observed at
bioventing projects in moderate climates. In Au-
gust 1992, the temperature of the passively
warmed plot was 4°C warmer than that of the
control plot, suggesting that passive warming is
somewhat effective. An economic analysis is
planned to determine which warming method, if
either, is more cost effective.
The Initiative's objectives are to more fully document, the performance of full-scale applications of bioremediation; provide, >
technical assistance to regional and state site managers; and pipvide information on treatabllity studies," design, and operation of '-
bioremediation projects. The Initiative currently is performing field evaluations of bioremediation at eight other hakar"dous'w^ste „
sites: Libby Ground Water Superfund site, Libby, MT; Park CitjrPipeUne,'Park,Gity/KS; Bendix-Corpojeation/Allied Automotive*;;
Superfund site, St. Joseph, Ml; West KL Avenue Landfill Superfund^site,5Ivalamazoo, Mt; Hill AirJFqrcfe' Base,Supeffund'site,,Salt 7
Lake City, UT; Escambia Wood Preserving Site—Brookhaven, Brookhaven; MS; Jleflly Tar and Chemical Corpbration'Supeifund »'<«
site, St. Louis Park, MN; and Public Service Company, Denver, CO; To obtain profiles on;tnese attditiqnal sites or tp be added to. *
the Initiative's mailing list, call 513-569-7562. For further information on ttie Bioremediatiori BielcL Initiative, contact Fran Kremer, ,
Coordinator, Bioremediation Field Initiative, U.S. EPA,pffice of Research and Development, 2<> West Martin tuther King Drive,
Cincinnati, OH 45268; or Michael Forlini, U.S. EPA, Technology Innovation-Office, Office of Solid Waslte an4 Emergency Response,'
401M Street, SW., Washington, DC 20460. \ >>, "'" '.">" - >„ " '/ >''''" -" ,„' s"" '- '"-> ,<-,''' <
^ -,'•.' ~rt~e, i- x. ' ' x . :> , ., , , '* ' f ! . , .
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