Reuse/Recycle: Recovery and reuse technologies for energetic materials, including both explosives and propellants, should be considered at explosives waste sites for several reasons. First, new recovery methods and potential uses for reclaimed explosive materials are rapidly developing. Second, recovery/reuse options reduce overall remediation costs by eliminating destruction costs and allowing the value of reclaimed materials to be recovered. Finally, EPA's treatment hierarchy, which is based on environmental considerations, favors recovery/reuse options over destruction technologies.

Soils and sludges contaminated with energetic materials present handling problems during recovery and reuse operations. USAEC has established a guideline that soils containing greater than 10% energetic materials by weight should be considered explosive during handling and transportation. As a general rule, soils and sludges containing less than 10% energetic materials by weight pass USAEC's nonreactivity tests. Reuse/recycle options are more feasible for contaminated soils and sludges meeting the nonreactivity criteria because they can be removed, transported, and handled using conventional equipment, which could provide a substantial cost savings.

Solvent Extraction: Solvent extraction is a technology that the Army originally determined to be infeasible for treating explosives-contaminated soils. The technology, however, might have potential for treating these soils if a few lingering technical issues can be resolved. In 1982, the Army conducted laboratory-scale solvent extraction on explosives-contaminated lagoon samples from a number of sites. Each sample was washed with a solution of 90% acetone and 10% water. This process achieved greater than 99% contaminant removals.

In 1985, the Army conducted a pilot-scale engineering analysis to determine the feasibility of full-scale solvent extraction. This analysis indicated that, for solvent extraction to be economically feasible, the number of required washes would have to be reduced, and acetone would have to be recovered and reused. Currently, the only available technology for recovering acetone is distillation, which exposes acetone to heat and pressure. Exposing a solvent that has been used to extract explosive contaminants to heat and pressure raises serious safety considerations. In fact, the distillation column used to recover acetone often is referred to as an "acetone rocket." Nevertheless, the Army believes that full-scale solvent extraction would be feasible if a safe, efficient, alternative recovery method were developed.

Soil Washing: A soil washing procedure, termed the Lurgi Process, currently is being developed in Stadtalendorf, Germany. Although no data have been published on the effectiveness of this process, initial reports suggest that the process can reduce levels of explosive contamination in soils to low ppm levels. As with all soil washing technologies, the Lurgi Process produces secondary wastes, such as washwater and concentrated explosives.

In the Lurgi Process, contaminated soils are excavated and processed in an attrition reactor, which detaches the explosive material from the soil particles. The remaining material undergoes a second process, which separates clean from contaminated particles. Clean particles are dewatered, separated into heavy and light materials, and returned to the site.