Review and Evaluation of Alternative Chemical Disposal Technologies (1996)

Destruction of the unitary chemical agent stockpile is a complex undertaking. However, the challenges at the Aberdeen and Newport sites are considerably lessened by the relative simplicity of the stockpiles at these sites: a single agent at each site, stored in bulk (ton) containers.

Because of concerns about emissions from incineration, the neighboring communities have insisted that alternative technologies be implemented at these sites. They are also concerned that the selected alternative be safe with respect to public health and the environment, cost-effective, and implementable within a reasonable time. Perhaps most important, they want to be meaningfully involved in the decision process.

The following findings and recommendations are based on the AltTech Panel's in-depth technical evaluation and assessment of five alternative technologies: catalytic extraction, electrochemical oxidation, gas-phase chemical reduction, stand-alone neutralization or neutralization followed by biodegradation for HD, and stand-alone neutralization or neutralization followed by biodegradation for VX. The panel evaluated these technologies for the particular application of destroying HD blister agent or VX nerve agent stored in bulk containers. The panel's findings and recommendations are specific to this application of the technologies and do not encompass other applications, including application to other agents or other storage sites. The panel believes that its efforts to obtain public views on the criteria used in these technical evaluations will result in public support and acceptance of its recommendations. Furthermore, the panel's findings and recommendations reflect information on environmental regulations relevant to the pilot-testing and eventual full-scale operation of an alternative technology.

General Finding 1. Since the 1993 NRC report, Alternative Technologies for the Destruction of Chemical Agents and Munitions (NRC, 1993), there has been sufficient development to warrant a reevaluation of alternative technologies for chemical agent destruction. However, the developmental status of the technologies varies widely, the time required to complete pilot demonstrations will also vary.

General Finding 2. All the technologies selected for the panel to review have successfully demonstrated the ability to destroy agent at laboratory-scale.

General Finding 3. Members of the communities near the Aberdeen and Newport sites want an alternative to incineration that has the following characteristics: operation at low temperature and low pressure; simplicity; the capability to test all process residuals prior to release; and minimal potential for detrimental effects, short term or long-term, on public health and the environment. Although the communities do not want treaty or legislative schedules to drive decisions on technology options, they want the stockpiles at the two sites to be destroyed as quickly as possible.

General Finding 4. Based on the panel's discussions with state regulators, all the technologies appear to be permittable under the Resource Conservation and Recovery Act and associated state regulations within one to two years of application submission. The time will depend on the complexity of the technology and the regulators' familiarity with it.

General Finding 5. As complete processing systems for chemical agent, all the technologies reviewed are of moderate to high complexity. Although components of each process are standard and proven, no alternative is an off-the-shelf solution as an agent destruction process. Any one of them will require extensive design review, hazard and operability studies, materials selection, and related work as it moves through the piloting stage to full-scale demonstration and operation. During this necessary preparation for implementing an agent destruction system, everyone involved should

bear in mind that most failures in complex, engineered systems occur not during steady-state, normal operations but during transient conditions such as startup, shutdown, or operator responses to deviations from design conditions.

Specific Finding 1. The Army required each TPC (technology proponent company) to demonstrate the capacity of its process to destroy agent in a government-approved laboratory. Each TPC supplied test results to the panel indicating the process had successfully destroyed both blister (HD) and nerve (VX) agents. Because to time constraints, the panel was not able to review and analyze in-depth the data from these important tests. However, two key issues stand out.

First, the tests were conducted under conditions that varied in different ways from conditions in a pilot-scale or fully operational facility. It is therefore inappropriate to expect that the particular DREs attained in the tests would be the same as DREs attained in an operating facility. It is also inappropriate to compare technologies on the basis of which attained more "9's" in the DRE results. Given the lack of comparability between the test conditions and the scaled-up facility for an individual technology and the differences in test conditions for different technologies, the panel has used the test results only to address, in yes-or-no fashion, whether a technology can destroy agent.

Second, the by-products of any agent destruction process are of significant concern to the panel, the neighboring communities, and the regulators. A DRE gives no information on the composition and concentration of by-products that may be hazardous to human health or the environment. The panel had insufficient time to analyze the comparability of the tests with respect to methods of detection of by-products, completeness of coverage of potential products of concern (particularly those produced in trace quantities), limits of detectability under the test conditions, and other parameters essential to understanding the toxicologic and environmental hazards associated with residuals from the technology. An in-depth, independent analysis of these test data will be necessary to support future Department of Defense decisions about proceeding with pilot-testing. This analysis may show that further independent testing is needed.

Recommendation 1. For any technology that is to be pilot-tested, the Army should support an in-depth analysis of the agent destruction test results by a competent, independent third party not associated with the Army or any of the TPCs. This analysis should address (1) the comparability of the test conditions to process conditions of anticipated pilot-scale and fully operational facilities, (2) the extent to which reported results for agent destruction and detection of by-products are comparable across the tests, and (3) weaknesses or omissions in the testing-whether for agent for the destruction or detection of by-products, including trace quantities of toxic by-products that must be addressed in subsequent testing of the technology as an alternative for agent destruction at Aberdeen or Newport.

Specific Finding 2. Current Army prohibitions on offsite treatment and disposal of process residuals unduly restrict the options for stockpile destruction. No toxicologic or risk basis for the proposed Army release standards has been developed. In addition, there appears to be an inconsistency among limits for airborne exposure and for residual concentrations in liquid or solid materials that are to be released from agent handling facilities to off-site facilities for subsequent treatment and disposal.

Recommendation 2a. Standards for releasing wastes should be evaluated on a clearly defined regulatory and risk basis that takes existing practices into account. Standards should be revised or established as necessary.

Recommendation 2b. The Army should review and revise current restrictions on off-site treatment and disposal of process liquid and solid residual streams to allow treatment and disposal of the process effluents from agent destruction at permitted off-site treatment, storage, and disposal facilities and at permitted FOTW (federally owned treatment works) for wastewater.

Specific Finding 3. The panel determined that the development status of the technologies assessed and the lack of long-term experience with their use for the destruction of chemical agent necessitate a comprehensive design review of any selected technology prior to the construction of a pilot plant. Reliability of the facility, as affected by system design, control, operation, maintenance, monitoring, and material selection, must be thoroughly evaluated.

Recommendation 3. A detailed, comprehensive design review of any selected technology or technologies should be performed prior to starting pilot plant construction. This review should examine reliability as affected by system design, controls, operation, maintenance, monitoring, and materials selection.

Specific Finding 4. The panel has found that, no matter which technology is selected for potential use at either site, the affected communities insist that they be included in a meaningful way in the process leading up to key decisions, including the decision to proceed to pilot demonstration. At a minimum, a meaningful community involvement includes:

• determining, with community input, the nature and extent of involvement the community wants and how it can be achieved
• ensuring that the infrastructure exists to support this involvement
• updating the TPC packages in the information repositories located in the affected communities to ensure that the public has access to the latest, most complete information
• seeking additional ways to sustain and deepen the dialogue between the Army and the communities and the exchange of views within the communities

Recommendation 4. The Army should take immediate steps, if it has not already done so, to involve the communities around the Aberdeen and Newport sites in a meaningful way in the process leading up to the Army recommendation to the Defense Acquisition Board on whether to pilot-test one or more alternative technologies.

Specific Finding 5. The risk assessment performed by MitreTek Systems, Inc., was not available to the AltTech Panel until very late in the preparation of this report. As was noted in Chapter 2, the panel assumes that more-rigorous, site-specific assessments will be done at an appropriate time before a full-scale facility for agent destruction is built and operations on agent begin. These required assessments include a quantitative risk assessment and a health and environmental risk assessment.

Recommendation 5. Before any technology is implemented at a stockpile site, an independent, site-specific quantitative risk assessment and a health and environmental risk assessment should be completed, evaluated, and used in the Army's risk management program.

The panel's evaluation criteria presented in Chapter 10 favor technologies with the following characteristics:

• inherent process safety, which includes consideration of the required safeguards or engineering controls, the potential for process upsets, the requirements for process control interlocking, reliability, and the hazard inventory
• technical maturity, as shown by such factors as the scale of demonstrated ability to process agent and commercial industrial experience with the equipment, systems, and processes that would be required for an agent destruction facility
• process simplicity, judged by such factors as the number of unit operations required and the ease of scale-up to a full-production facility

Based on these priorities, the panel reached consensus on the following findings and recommendations on alternative technologies to be pilot-tested for agent destruction at the Aberdeen and Newport sites.

Specific Finding 6. Aqueous neutralization of the chemical agent HD followed by biodegradation of the hydrolysate surpasses the priority criteria listed above. This technology has the following advantages:

• Among the alternatives reviewed, it has the largest-scale successful demonstration with agent.
• The equipment required has been proven through extensive use in industry for processes similar to those planned for use in agent destruction.
• The principal unit operations are independent batch processes that do not require elaborate safety interlocking.
• Because the process involves batch processing of liquids, hold-and-test analyses to determine batch composition can be readily performed at several points in the process.

• The process is performed at low temperature and near atmospheric pressure; the hazard inventory in general is low.
• The selection of materials of construction appears to be straightforward.
• No step in the process involves combustion; therefore no combustion products are emitted.

Recommendation 6. The Army should demonstrate the neutralization of HD at Aberdeen on a pilot-scale.

• The AltTech Panel recommends biodegradation of hydrolysate from HD at an off-site treatment, storage, and disposal facility (configuration 4 in Chapter 7) as the most attractive neutralization configuration. Of the four neutralization configurations described in Chapter 7, this one is the most reliable and robust; has little potential for process upsets; makes more use of existing facilities and trained staff, rather than requiring new facilities and newly trained staff; should be most rapidly permittable; should have the shortest implementation schedule; and should be the quickest and easiest to decommission.
• The second best configuration is neutralization with biodegradation on-site, followed by disposal of the aqueous effluent through a FOTW. If this option is selected, the panel recommends separating the VOCs (volatile organic compounds) prior to biodegradation, followed by off-site treatment and disposal of the VOCs.

Specific Finding 7. Neutralization of chemical agent VX with sodium hydroxide solution destroys agent effectively and substantially lowers the toxicity of the process stream. With respect to the priority criteria listed under Technology Selection, this technology followed by off-site treatment and disposal of the hydrolysate has the same relative advantages as neutralization of HD. One difference, however, is the uncertainty about the appropriate disposal method for VX hydrolysate.

Although biodegradation of oxidized VX hydrolysate has been demonstrated in the laboratory, as of May 1996 limited treatability studies have not demonstrated biodegradation at a TSDF, even though a TSDF has disposed of VX hydrolysate from bench-scale testing within its permit requirements. It is possible, although not yet established by adequate testing, that the hydrolysate has sufficiently low toxicity associated with its organic products that complete biodegradation prior to discharge may not be necessary.

Furthermore, treatment of VX hydrolysate by existing commercial TSDF processes other than biodegradation is likely to be possible. Therefore, any treatment at a TSDF, whether by biodegradation or another proven and tested process, that results in appropriately low toxicity and low environmental burden in the discharge from the TSDF is a suitable disposal option for VX hydrolysate. As an on-site option for the disposal of hydrolysate, the panel believes that existing, commercially proven processes other than biodegradation could be used. The residual concentrations of agent allowable under chemical weapon treaty negotiations are likely to be less stringent than the concentrations required by the environmental permits for the destruction and downstream disposal facilities.

Recommendation 7a. The Army should pilot-test VX neutralization followed by off-site treatment of the hydrolysate at a permitted TSDF (treatment, storage, and disposal facility) for potential use at the Newport site, but only if the effluent discharged from the TSDF has been shown to have acceptably low toxicity and results in minimal environmental burden.

Recommendation 7B. If on-site disposal of VX hydrolysate is preferred to shipping it off-site for TSDF treatment, existing commercial processes other than biodegradation should be considered. The panel does not recommend on-site biodegradation because of the need for cofeeding a substantial amount of carbon substrate and because of limited success to date in testing on-site biodegradation.

Specific Finding 8. Electrochemical oxidation is the next best alternative for destroying VX at the Newport site. Although the developmental status of this technology is not as advanced as the status of other technologies considered, the panel is confident that the remaining development can lead to a successful pilot demonstration. Although power requirements for this technology are considerable, there is sufficient power available to operate a facility. All process residuals can be handled with commonly used procedures. With respect to the priority evaluation criteria listed under Technology Selection, electrochemical oxidation has the following advantages:

• The required equipment has been proven through extensive use in industry, although it has not been used for chemical agent destruction.
• The principal operations are performed independently and do not require elaborate safety interlocking.
• The semibatch operation can be halted quickly with little danger of a process upset or of stressing the equipment and materials.
• Because many of the process streams are aqueous solutions, hold-and-test analyses to determine stream composition can be readily performed.
• The process is performed at low temperature and pressure with aqueous reaction solutions.
• No step in the process involves combustion; therefore no combustion products are emitted.

Recommendation 8. If successful off-site treatment of VX hydrolysate at an existing TSDF is not confirmed by appropriate treatability studies, and successful on-site treatment of VX hydrolysate with existing commercial processes cannot be demonstrated, then the Army should pilot-test the electrochemical oxidation of VX for potential use at the Newport site.