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 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
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.