Rhizosphere-Enhanced Bioremediation of Petroleum, Oil and Lubricant (POL)-Contaminated Soils at Three Sites in Alaska

Site Name:

Multiple (3) POL-Contaminated Sites


- Annette Island site, Former U.S. Army Air Force Landing Field, Metlakatla, Alaska
- Galena/Campion site, Former Air Force Station, Galena, Alaska
- Barrow sites, Former Tank Farm, and Former Dry Cleaning Facility, Barrow, Alaska

Period of

- Demonstrations at Annette Island and Galena/Campion began in Summer 1998 with site installation including soil preparation and seeding
- Soil preparation and seeding at Barrow began in Summer 1999
- Performance data available through Summer 2000


Field demonstration

Rhizosphere-enhanced bioremediation
- Used a seed mixture of three species of cold-tolerant grasses
- Annual ryegrass (10% to 15%)
- Arctared red fescue (60% to 70%)
- White clover (20% to 25%)
- Minimal soil preparation prior to seeding
- Surface-applied seeds with handheld seeders and pressed seed into soil
- Added maximum permissible (less than 2,000 mg nitrogen/kg of soil) quantity of standard agricultural fertilizer
- Prepared control area with fertilizer but no seeds
- Prepared control area with seeds but no fertilizer

Cleanup Authority:
Not applicable

Varied by site

Diesel range organics (DRO) and gasoline range organics (GRO)
- Annette Island: Soil--fuel-related contaminants--specific information not available
- Galena/Campion: Soil--DRO (1995 data)--36 mg/kg to 75,000 mg/kg; GRO (1995 data)--59 mg/kg to 7,500 mg/kg
- Barrow:
- Dry Cleaning Facility: Soil (1995 data) – DRO – 230 mg/kg to 810 mg/kg; GRO – below detection limit to 85 mg/kg; PCE
- Tank Farm: Soil (1994 data) - Total petroleum hydrocarbons – 47 mg/kg to 9,400 mg/kg; lead – 8.1 mg/kg to 365 mg/kg; BTEX, halogenated aliphatics, PAHs, phenolics, solvents and inorganic compounds were also detected

Waste Source:
- Annette Island: Presumed to be from operations involving a fuel storage tank farm
- Galena/Campion: Presumed to be from operations involving a heating fuel storage tank farm
- Barrow: From operations related to a former dry cleaning facility and former bulk fuel tank farm; bulk fuel tanks contained diesel fuel, gasoline, Mogas and JP-5 jet fuel

Type/Quantity of Media Treated:
- Surface soils, mainly coarse sand and gravel marine beach deposits, but silty in vegetated areas
- An estimated 7,000 cubic yards of petroleum contaminated soil present
- Soils remain frozen through most of the year, but thaw to a maximum depth of 55 inches in August or September and refreeze by late October
- Groundwater occurs only in the thawed zone above the permafrost, and there is no significant flow

Purpose/Significance of Application:
- To demonstrate remediation of POL-contaminated surface soils in cold climates using cold-tolerant plants
- To determine relative effectiveness of fertilized and planted areas versus unfertilized areas and unplanted areas
- To study relationship between contaminant degradation and root-zone microbes.
- To study microbial population and composition

Regulatory Requirements/Cleanup Goals:
- Short term goal – to achieve reduction in contaminant concentrations; long-term goal – to restore Native American lands contaminated by DoD
- Quantitative cleanup goals were not provided

- Contaminant concentration were reduced (quantitative results were not available)
- Significant plant growth was observed in fertilized areas
- Long term cleanup goals are anticipated to be achieved only after continued remediation during future thaw periods

Cost Factors:
- Capital cost - $7,250; operation and maintenance - $1,400 per year
- Other costs - $6,000 per year (includes long-term monitoring, regulatory oversight, compliance testing/analysis, excavation , and disposal of residues
- Total cost (based on a 10,000-ft2 treatment area, 2-ft treatment depth, and 10 year period of operation) - $27,250

Rhizosphere-enhanced bioremediation was demonstrated at field-scale at three sites (Annette Island, Galena/Campion and Barrow) in Alaska. The contaminants at the sites were mainly petroleum hydrocarbons, including gasoline range organics (GRO) and diesel range organics (DRO). Barrow also had trace-level tetrachloroethene (PCE) and daughter products in the soil as a remnant of a removal action at a former dry cleaning facility. Demonstrations at all three sites included fertilizing and seeding of contaminated areas with a mixture of three cold-tolerant grasses. Installation at Annette and Galena/Campion, including soil fertilization and seeding, was conducted in Summer 1998. At Barrow, soil fertilization and seeding was completed during the next thaw-period in Summer 1999. Progress was monitored at all three sites at least until Summer 2000. Satisfactory plant growth was observed in fertilized and seeded areas and contaminant concentrations were reduced in these areas. Quantitative cleanup goals were not provided for the demonstration. The capital cost for the was $7,250, and the O&M cost was $1,400 per year.