Quick Cleanup at Andrews AFB

A highly contaminant-impacted site at a service station on Andrews Air Force Base in Maryland was recently cleaned up after only 11 months of accelerated bioremediation. The cleanup was originally projected to take 28 years.

The in-situ cleanup used a recently-introduced bioremediation technology, ORC Advanced™, to eliminate high concentrations of petroleum hydrocarbons that had resisted earlier cleanup attempts with conventional technologies, at a total cost less than one-third the original estimate of over a million and a half dollars.

The cleanup was the first environmental performance-based contract (PBC) to be completed for the Air Force in Maryland, as part of a government-wide shift toward this kind of contracting vehicle.

The five acre site had several “hot spots” of concentrated contamination where seven large underground gasoline and oil storage tanks had been removed. From there, dissolved contaminants had penetrated deep into the groundwater, forming a plume that covered an area of approximately five acres. Levels of benzene, toluene, ethylbenzene, and xylenes (BTEX) and methyl-tertiary butyl ether (MTBE) in the groundwater tested as high as 60,000 parts per billion. The Air Force had tried several times to clean the site, but residual product near the former tanks prevented success.

By November 2003, when the Air Force retained BEM Systems, the most feasible option included costly excavation and groundwater extraction/treatment, followed by 16 years of long-term monitoring and maintenance (until 2031) before the land would be available for all uses. The projected cost to complete was upwards of $1.5 million.

In December 2003, 2180 tons of soil at the contamination source area was excavated and disposed of appropriately off site. The backfill was treated with 500 pounds of ORC Advanced in powder form to stimulate bioremediation in the soil.
BEM and its project partner MACTEC Engineering then injected nearly 12 tons of ORC Advanced slurry in a grid pattern into and across the surrounding plume area. As the compound steadily released additional oxygen into soil and groundwater over the following months, it sped the growth of particular aerobic microbes which converted the soil contaminants, including BTEX and MTBE, into harmless end-products such as ethane, carbon dioxide and water.

The cleanup was also completed substantially under budget at approximately $500,000. BFN