Air Sparging at Fort Greely, Alaska Presented by Aung Syn & James Powell

Location The Texas Tower Site, U.S. Army ’ s Fort Greely military facility. Population 461 residents.

Background The Texas Tower Site consists of four buildings. While demolition of one of the buildings in 1990, a release of petroleum hydrocarbons was discovered. Originated from an underground fuel line which supplied heating oil to the demolished building from an aboveground storage tank.

Contaminant Soils consisted mainly of sand, gravel, cobble, and silt. Approximately 6,300 cubic yards of contaminated soil. Spread: vertically 50 feet deep and horizontally off an area of 5,655 square feet. Groundwater was encountered between 23 and 50 ft below ground surface.

Contaminant Diesel fuel (No. 2 fuel oil) consists of unbranched paraffin. Flammability: High Toxicity: High Two of the three monitoring wells where contaminated.

Technology Used Method i) Air Sparging System Two air sparging wells drilled of depth 55 ft with 2-inch- diameter. Provided cfm of air to the saturated zone. Operated for 18months.

Method ii) Soil Vapour Extraction System Three SVE wells were drilled to 52 feet with 4- inch-diameter. Soil vapour was removed from the wells at a rate of 600 cfm. Operated for 18months.

On 15 August, 1995, 4,000 gallons of nutrient solution was injected into the SVE Wells. Nutrient solution was a mixture of 50 lbs of fertilizer to 1,000 gallons of water. Use of micro organisms to degrade contaminants to obtaining harmless chemicals as end products. Method iii) In Situ Bioremediation

Timeline

Result

Conclusion Treatment in soil and groundwater met the remedial goals. Highly contaminated soil had been excavated and treated off site. The leaking fuel lines that had been the source of the release had been removed. No compounds for which maximum contaminant levels have been detected at the site for more than two years of monitoring after completion of cleanup. Total Cost of Cleanup: $295,760