- Soil was pre-screened using a two-inch bar screen.
- Pre-screened soil was fed to the on-site, direct-fired thermal desorption unit.
- Soil was treated at nominally 500°F with a throughput of 40-60 tons per hour.
- Off-gas was treated with a baghouse and afterburner.
- Treated soil was used as backfill on site.
Managed under the Formerly Used Defense Sites Program and the Installation Restoration Program, with USACE serving as lead agency. USACE solicited review comments, as appropriate, from the U.S. Air Force and ADEC
|State Point of Contact:|
State of Alaska Department of
Contaminated Site Program
555 Cordova Street
Anchorage, AK 99501
Bernard T. Gagnon
USACE, Alaska District
P.O. Box 898
Anchorage, AK 99506-0898
- BTEX and Petroleum Hydrocarbons
- GRO, DRO, and total recoverable petroleum hydrocarbons (TRPH)
- Maximum contaminant concentrations were 300,000 mg/kg TRPH and 11,000 mg/kg DRO
Oil spills (contamination was located primarily in an outfall ditch connected to a floor drain inside a building, near USTs and ASTs, and at drum and warehouse areas)
Type/Quantity of Media Treated:
- 9,500 yd3 of soil was treated
- Approximately 10% of soil was clayey silt; remainder was sand or sand with gravel
- Moisture content 11%
Purpose/Significance of Application:
Application of thermal desorption to treat sandy soil contaminated with diesel fuel at a remote site in Alaska.
Regulatory Requirements/Cleanup Goals:
- Cleanup goals for this application were based on the results of negotiations with ADEC. They consisted of the following cleanup goals: DRO (200 mg/kg), GRO (200 mg/kg), TRPH (200 mg/kg), BTEX (15 mg/kg).
- An air quality permit issued by the State of Alaska required air emissions to meet the following limits: particulate matter (<0.05 gr/dscf), and carbon monoxide (<100 ppmv and 2.39 lbs/hr).
- The thermal desorption unit at Port Moller achieved the cleanup goals after three months of operation.
- Of the 118 treated soil samples analyzed, 115 (97 percent) achieved the cleanup goals after one pass through the desorption unit. The three samples that did not achieve the cleanup goals after one pass were treated at relatively low soil temperatures (less than 400 °F). Those soil samples were retreated and subsequently achieved the cleanup goals.
- Air emissions testing was conducted at the site, but no data were available for review. However, analytical data from an application similar to that at Port Moller met the state's requirements for air emissions.
- USACE Alaska Division used an innovative approach to procuring a remediation contractor for this application. That approach was based on the use of unit prices established by the government for specific activities associated with the remediation and solicitation of bids as a percentage of the unit prices.
- The actual cost of thermal desorption of contaminated soil at Port Moller was $3,325,000 (for activities directly attributed to treatment), or $350 per yd3 of soil treated (9,500 yd3 treated).
The Port Moller Radio Relay Station (RRS) was constructed in the late 1950s and served as a communication link between Cold Bay and Port Heiden, Alaska. Until 1969, a Defense Early Warning line facility and the White Alice Communication System facility were co-located at the site. From 1969 to 1978, the site functioned as a RRS, and the site was abandoned in 1978. The site consists of the White Alice facility (buildings and antenna) located on a plateau at an elevation of 1,000 feet, and a fuel storage and supply facility located on the shoreline at the foot of the slope leading to the plateau.
In 1994, the USACE demolished the buildings, removed the fuel tanks, constructed a landfill for the disposal of debris, installed monitoring wells, identified areas of soil contamination, and seeded the landfill and other disturbed areas. In addition, a treatability study was conducted on contaminated soil from the site to determine the relative effectiveness of treatment using thermal desorption, soil washing, and bioremediation. Thermal desorption was chosen for the full-scale site remediation based on the results of the treatability study.
The contractor mobilized the remediation equipment to Port Moller in May 1994. Approximately 9,500 yd3 of contaminated soil were treated using an oil-fired portable thermal desorption unit, which had a rated capacity of 70 tons per hour. The soil was treated in three months of operation and the treated soil was used as backfill to grade the site.
The total cost for treatment of contaminated soil at Port Moller was $3,919,736, which includes $3,325,000 for treatment and almost $600,000 for mobilization and demobilization, due to the remote location of the site.