You are here:
REMEDIATION OF A MAJOR JET FUEL SPILL BY BIOSLURPER AND NATURAL BIOVENTING TECHNOLOGY ON AN ISLAND AIR BASE
Citation:
Kampbell*, D H., J. E. Hansen, AND M. K. Husain. REMEDIATION OF A MAJOR JET FUEL SPILL BY BIOSLURPER AND NATURAL BIOVENTING TECHNOLOGY ON AN ISLAND AIR BASE. Presented at SETAC Asia/Pacific Conf, Christchurch, NZ, 09/28-10/01/2003.
Description:
The Indian Ocean island of Diego Garcia has served as a base for B-52 bombers. In 1991 an underground transfer pipeline fracture was discovered after a spill exceeding 200,000 gallons occurred. The hydrogeology is fresh water at less than ten feet down overlying more dense salt water in a fragmented coral matrix. Water table oscillations due to tidal action are near two feet twice daily. Initially 140,000 gallons of JP 5 fuel product was removed by suction hoses. The remaining fuel product is being removed by a bioslurping system of vacuum-enhanced skimming at the water table. The mist collected is transferred to an oil/water separator. Operation of the bioslurper units on an off/on basis depending on air traffic for six years has removed about 70,000 gallons fuel. In addition the bioslurper design draws oxygen rich air into the unsaturated soil to enhance aerobic degradation of the fuel hydrocarbons. After five years of irregular operation product thickness has dropped from over one foot to a sheen. Three lines of evidence are being used to evaluate cleansing of the fresh water by natural attenuation. One is the historical loss of hydrocarbon contaminants. The other is that subsurface soil sampling has detected elevated levels of carbon dioxide and methane and the absence in water of dissolved oxygen and nitrates. Sulfate reduction and methanogenesis have been identified as the primary degradation active processes. Also very active microbial degradation processes are occurring as indicated by the presence of volatile fatty acids. It has been estimated that the operation of the bioslurper system is about five percent of the alternative cost of site excavation and replacement with clean fill. Overall, the bioslurping/natural bioventing technique has been both cost and operational effective, simple, and easy to maintain.