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Bioremediation in the Field
<br /> however,that stricter air flow management could have
<br /> R Air Force resulted in more degradation and less volatilization of
<br /> t Thr x La u n e h e s contaminants. Similar projects are being undertaken in
<br /> r cooperation with EPA's Bioremediation Field Initiative
<br /> Bioventing at Hill AFB in Utah and at Eielson AFB in Alaska.
<br /> Initiative The Tyndall AFB project demonstrated several advan-
<br /> tages of bioventing over alternative oxygen delivery
<br /> 1 May, the U.S. Air Force launched an extensive pro- Systems. First,bioventing uses a low-pressure air flow,
<br /> ram to examine bioventing as a remedi�l technique so vapor-phase hydrocarbons that are volatilized dar-
<br /> t contaminated Air Force Base (AFB) sites across the ing the venting process are biodegraded before they
<br /> .)untrv. Bioventing is a promising new technology escape from the soil. Thus, bioventing eliminates the
<br /> sat promotes aerobic degradation of contaminants in expensive off-gas treatment step, reducing remedia-
<br /> .)il by direct injection or vacuum extraction of air. The tion costs by 50 percent or more. Second, bioventing
<br /> ,ir Force Bioventing Initiative targets 55 sites with jet appears to be the only cost-effective, in situ technique
<br /> _lel, diesel fuel, or fuel oil in soil, for remediating nonvolatile or low volatile hydrocar-
<br /> bons like fuel oil and diesel. Third, bioventing can be
<br /> i selecting sites for the initiative, the Air Force looked used to treat contaminants in areas where structures
<br /> )r characteristics appropriate for bioventing, such as and activities cannot be disturbed, because air injec-
<br /> eep vadose soil, heavy hydrocarbon contamination, tion wells, air blowers, and soil-gas monitoring wells
<br /> nd high air permeability. Air Force project coordina- form a relatively noninvasive apparatus.
<br /> )r Major Ross Miller reports that the chosen sites
<br /> -present a wide range of depths to ground water, There are currently over 4,300 documented Air Force
<br /> vdrocarbon concentrations, and soil textures, disposal sites requiring investigation and possible re-
<br /> mediation. At least half of these sites are contaminated
<br /> hort-term testing began at several sites in Vlav to with petroleum hydrocarbons. If the Air Force
<br /> etermine the air permeability and in situ respiration Bioventing Initiative is a success, bioventing could
<br /> e soil. At most sites, the test system consists of a plav a significant role in achieving the Air Force's goal
<br /> le vent well with screening in the unsaturated of initiating cleanup of all sites by 2000.
<br /> one and three soil-gas monitoring wells at various
<br /> istances from the vent well. By injecting air through For more infomlation on the Air Force Bioventing
<br /> :Ze vent well and measuring pressure changes in the Initiative, contact Major Ross Miller of the Air Force
<br /> oil-gas monitoring vtirells, researchers establish the Center for Environmental Excellence at 512-536-4331.
<br /> oil's air permeability and the radius of influence of
<br /> .-ieinjection well-The rate of biodegradation in the soil Bioremediation Field
<br /> then determined by temporarily shutting do%ti-n air
<br /> ejection to the vent well and measuring the rate of in initiative Holds open
<br /> itu oxygen respiration in the monitoring wells.
<br /> House at Eielson A F B
<br /> Vhere short-term tests reveal high air permeability
<br /> nd degradation rates, the Air Force will initiate long-
<br /> bioventing tests. The requisite apparatus and an Eielson Air Force Base in Fairbanks,Alaska,site of
<br /> peration manual will be provided at each site so that a field study of in situ bioventing and soil warming
<br /> ,ase personnel can monitor the progress of long-term methods, will host an open house in January 1993.
<br /> esting for 2 or 3 years. At small sites, long-term testing The bioventing project,sponsoredjointly:by EPA's
<br /> .gay well complete the necessary remediation. At large Bioremediation Field .Initiative and the U.S. Air
<br /> ites, data from long-terns testing will be used to de- Force, has demonstrated successful 1year round
<br /> ign full-scale bioventing systems. Preliminary testing bioremediation in both heated and unheated soils,
<br /> .as been completed and full-scale systems installed at despite.the harsh winter dirnate.::;; .:
<br /> Teale, Eglin, Eielson, F.E. Warren, kill, Galena, New- The open house will include a formal presentation:
<br /> rk, Offutt,and Plattsburgh Air Force Bases. of results anda.tourof the site inoperatian Project
<br /> he Aix Force's decision to examine bioventing on Dentists frorritheEPAR�skReducnonEngineer
<br /> h a large scale was prompted by a successful dern- ing Laboratory; Air'<Force Civil Erigi.neerl Sup
<br /> ration of the tQchnology at Tyndall AFB in Florida. port Agency, Air Force-Center for::Enrnronrrterrtal
<br /> Excellence,EieiSon AFB
<br /> 1t this site, bioventing was coupled with moisture ,aridBattelle Laboataries
<br /> ddition to remediate jet fuel in sandy unsaturated will attend.
<br /> oil. Before bioventing was initiated, hydrocarbon Contact Gregory.Savles of EPA at 513-569777607 to
<br /> oncentrations ranged from 30 to 23,000 mg/kg. After receive the final; dates and,`ageiida for. the open
<br /> months of treatment, 32 kg of hydrocarbons had house_
<br /> liodegraded from one treatment cell. It was estimated,
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