Soils washing for removal of heavy oil: Naval Air Engineering Center, Lakehurst, NJ

With the recognition that large tracts of land are currently unusable as a result of either accidental spills or past industrial practices (such as oil field development), the USEPA Office of Research and Development evaluated soil washing as an alternative remedial technology for heavy oil contaminated soil at a site located on the Naval Air Engineering Center (NAEC), Lakehurst, New Jersey. The researchers used a self-contained, 100-pound-per-hour soil washer. Electrical, pneumatic, and fluid-pumping capabilities were provided by the trailer-mounted system at a remote No. 6 type oil spill site at the Navy base. Chloroform extracts of the contaminated sandy soil recovered a 0.91 gram/milliliter, 950 centistoke viscosity, dark brown, non-PCB oil. By using a surfactant/solvent solution at ambient temperatures, contaminant levels on the soil were reduced from 3.8% (38,000 milligram/kilogram-RCRA hazardous waste designation) to as low as 0.035% (350 milligram/kilogram) oil concentration. Supplemental laboratory evaluations extending the pilot field evaluations showed at elevated temperatures (120F) that residual oil contamination was less than 0.01% (100 milligram/kilogram). This final oil concentration in the treated soil would be defined as clean under the New Jersey Environmental Cleanup and Responsibilities Act (ECRA). A continuous belt press filter was used to recover the oil in a 47% solids cake that could be used as a secondary fuel feed to a waste boiler. The wash water solution was treated and recycled permitting economical operations