Technologies were reviewed to determine if a common process failure (e.g., explosion, corrosion, mechanical failure, operator error, incorrect feeds, service failure, etc.) under normal operating conditions could lead to serious worker, community, or environmental damage. The following factors were considered:

• minimal storage and transportation of hazardous materials

• minimal toxicity and flammability of all materials

• temperatures and pressures below the threshold values that challenge reliable containment

Technologies were evaluated for their consistency in achieving a standard (in this case, destruction) of neutralent. The following factors were considered:

• efficiency of detoxification of the neutralent (i.e., solid wastes could be disposed of in a landfill and liquid wastes released to a POTW)

• integration into a system for the destruction of nonstockpile materiel

Technologies were evaluated for serious regulatory obstacles that would prevent environmental and/or operational permitting. The following factors were considered:

• potential major delays in obtaining permits under federal (and international), state, or local regulations

• potential for meeting schedules of international treaties

The committee evaluated the technologies on the principle of “green chemistry” (Mulholland and Dyer, 1999). In other words, pollution prevention and waste minimization practices are implemented at the beginning of the process (pollution prevention) as opposed to after the fact (pollution abatement). The following factors were considered:

• minimal addition of processing materials¹ that would require treatment, disposal, regeneration, recycling, or other handling

• minimal number of processing steps, which all have an incremental environmental burden in potential leaks and energy, maintenance, shutdown and start-up, and clean-out requirements

• minimal toxicity of emissions, wastes, or other material that require treatment, disposal, regeneration, recycling, or other handling²

• operating temperatures and pressures as close to ambient as possible

• minimal corrosion, plugging, sensitive process-control parameters, and other operating difficulties

• minimal high-temperature vapor streams that require high-quality treatment

Once the selected technologies had been evaluated according to top priority criteria, they were evaluated by the important criteria.

A robust technology can function successfully in stable continuous operation. The term “continuous” means the technology can treat neutralent from beginning to end and does not require another technology as an intermediate step before final disposal. Continuous also means that feedstock can be continuously supplied or supplied in the batch mode. Operation of a robust technology has the following characteristics:

• tolerance of normal variations (differences in concentrations of hazardous materials or chemical agents)

• start-up and shutdown of a facility without major complications or delays

• operation at small scale or large scale, as required

• capability of treating a wide range of potential feeds (neutralents from the RRS and MMD)

Although the committee did not conduct a cost analysis for each technology, cost was estimated based on past experience and knowledge. The following cost factors were considered:

• total costs, including capital and operating costs

• costs per unit of feed

The following factors related to practicality were considered:

• minimal training for operators (average skill levels for the chemical industry)

• use of standard instrumentation for monitoring and process controls

Two factors were considered in this category:

• likelihood of finding a vendor

• Zlikelihood that supplies of raw materials will be available

The main factor in space efficiency was the weight, area, and volume of operating equipment per volume of material processed.

The following factors were considered:

• recycling of materials as part of the internal operation of the facility

• shipment of wastes off site for beneficial reuse

• use of recycled materials from external sources