Application of in situ bioventing in the remediation of deep soils at arid sites
In situ bioventing, or low flow rate soil ventilation for the enhanced aerobic biodegradation of petroleum hydrocarbon contaminants, has been shown to be a cost-effective remedial alternative for vadose zone soils. The success of the technology relies on the ability of indigenous soil microorganisms to utilize hydrocarbon contaminants as a primary growth substrate. The rate of hydrocarbon biodegradation at a given site depends on a variety of factors, including the concentration of soil microorganisms present. Parsons Engineering Science, Inc. (Parsons ES) has conducted bioventing pilot tests at six U.S. Air Force sites in Arizona, Nevada, New Mexico, and Utah, where petroleum hydrocarbon contamination has migrated to depths ranging from 19.8 to 67 meters (65 to 220 feet) below ground surface (bgs). Test results demonstrated that bioventing can be a viable remedial alternative in deep soils in and regions. Petroleum biodegradation was shown to be occurring at significant rates at three of the six subject sites. Average oxygen consumption rates ranged from 4.6 to 12.8 percent per day during initial in situ respiration testing at these three sites. At five of the six sites, average soil total Kjeldahl nitrogen (TKN) concentrations ranged from 50 to 150 milligrams per kilogram (mg/kg), generally indicating that significant bacterial populations may exist in deep soils at these sites, and that enough nitrogen was present to support aerobic hydrocarbon biodegradation. At Site 35, located at Davis-Monthan Air Force Base (AFB) in Arizona, the average TKN concentration in soil was 16 mg/kg and the average oxygen consumption rate was 0.22 percent per day, demonstrating that the lack of a significant microbial population may contribute to the low hydrocarbon biodegradation rates estimated at this site. During these initial pilot tests, soil moisture was found to be present in adequate amounts at all subject sites to support aerobic petroleum hydrocarbon biodegradation.
- OSTI ID:
- 416883
- Report Number(s):
- CONF-951023-; TRN: 96:005001-0040
- Resource Relation:
- Conference: 68. annual conference and exposition of the Water Environment Federation, Miami Beach, FL (United States), 21-25 Oct 1995; Other Information: PBD: 1996; Related Information: Is Part Of WEFTEC `95: 68th annual conference & exposition; PB: 498 p.
- Country of Publication:
- United States
- Language:
- English
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