Abstract

The NATO Advanced Research Workshop on "Destruction of Toxic Military Materials" brought together experts on problems of disposal of chemical weapons in the field and on technologies with possible application to these problems. Disposal problems were described for the US, Germany, Russia, Indonesia, and Iraq.

Technologies discussed were high temperature (incineration, plasma torch, molten metal), medium temperature (pyrolysis, supercritical and wet air oxidation, hydrogenation), and low temperature (metal oxide catalysis, silver(II) oxidative electrolysis, dry HCl).

Participants developed a set of disposal problem scenarios and made recommendations for best technologies for each scenario. This report includes descriptions of the problems in the field, the technologies, and the scenarios and recommendations for dealing with them.

The workshop was held in Naaldwijk, The Netherlands during 22-27 May 1994. Send inquiries to Dr. Robert W. Shaw, US Army Research Office, Research Triangle Park, NC 27709; int +1-919-549 4293, fax int +1-919-549 4310, shaw@aro-emhl.army.mil or to Dr. Johan Santesson, The Provisional Technical Secretariat of the Preparatory Commission for the Organization for the Prohibition of Chemical Weapons, Laan van Meerdervoort 51. NL-2517 AE, The Hague, The Netherlands, int +31-70-376 1773, fax int +31-70-360 0944, ICA Division, OPCWl

Acknowledgement

The Participants in the Advanced Research Workshop thank The Scientific and Environmental Affairs Division of NATO for major support of this meeting. The Workshop Directors especially thank Professor Luigi Sertorio, Program Director of NATO, for his kind assistance.

Table of Contents

Introduction

Session 1: Current Field Methods

Session 2: Chemical Weapon Destruction Scenarios

Session 3: Chemical Weapon Destruction Technologies

Recommendations from the Workshop

Summary of the Recommendations

Conclusions of the Workshop Participants

Workshop Agenda

Workshop Participants

Introduction

The NATO Advanced Research Workshop on "Technologies for Destruction of Military Toxic Waste in the Field" was held in Naaldwijk, The Netherlands during 22 - 27 May, 1994. This was a research workshop; policy was not discussed. The workshop was limited to about 25 invited participants - all experts in their fields.

We sought to develop specific recommendations for destroying chemical [1] and explosive weapons. These weapons have been classified into two groups: "stockpiled" materials are identified, characterised materials stored in ammunition depots in a controlled environment; other items are "non-stockpiled" materials, for example, old munitions discovered during excavation or washed up on beaches, damaged materials in an occupied war zone, abandoned chemical weapons, etc. These non-stockpiled materials were the primary focus of the workshop. Abandoned chemical weapons may be an especially important type of non-stockpiled material.

The workshop consisted of Presentation and Discussion Sessions and Working Group sessions. Experts with experience in dealing with military materials in the field spoke in the session "Current Field Methods"; those expert in use of new technologies in the session "Chemical Weapon Destruction Scenarios". The session "Chemical Weapon Destruction Scenarios" established a range of representative toxic military waste disposal problems. The Working Groups matched the scenarios with technologies and developed specific recommendations.

Participants were not able to cover all possible technologies for destruction of non- stockpile materials, so the organisers chose those that appeared most promising. Methods chosen were those best suited for clean- up of concentrated materials - the munitions - but attention was also given to dilute wastes - contaminated soil and water.

Non-stockpiled materials are a growing technical challenge because of their variety and the circumstances in which they may be found. Destruction of stockpiled chemical weapons has already been the subject of extensive studies by technical committees.[2]

Although the workshop dealt with technical issues, the participants recognised circumstances that could constrain technical approaches, e.g., rules against transporting chemical weapons in some states or countries, public opinion, etc.

Perceived Problems

In an orientation discussion, lists of non-stockpiled materials, in decreasing order of importance, were made by participants (see Table 1). These lists depended, of course, on the experiences and responsibilities of their makers.

Table 1. Lists of non-stockpile items in decreasing order of importance.

* The Iraqi CW stockpile was in such condition that it was regarded as non-stockpiled material.

These initial discussions turned up important problems and considerations. In some countries, munitions can be moved to a secure area and blown up. This procedure has a long history and some participants argued that, considering risk to the clean-up crew as well as to people in the vicinity and to the environment, detonation is the safest way of dealing with unstable materials (e.g., buried munitions with picric acid fuses).

A participant with extensive field experience referred to the desperate need for improved means of handling munitions and separating the energetic material (explosive charge or rocket propellant) from the chemical weapon agent. This crucial, difficult problem was beyond the scope of the workshop, but we recognise that it requires considerable attention.

Experience from the clean-up of Iraqi chemical munitions and the disposal of old chemical weapons in Europe established the most complex problem: explosively configured weapons. The chemical agent chamber required venting of overpressure developed during exposure to desert temperatures, but the presence of chemical agent made venting potentially dangerous. Several participants suggested an explosion containment vessel; this idea had considerable appeal and participants came back to it in their recommendations.

More information on the properties and chemistry of chemical weapons agents will enable a significantly more effective program for their destruction. We need more information on chemical rates of reaction and products formed. The workshop participants found problems with arsenical agents particularly difficult because of their complex chemistry and the added difficulty of containing arsenic in some of the technologies considered.

Chemical Treatment of Chemical Weapon Agents

The workshop included experts on chemical agent chemistry and their expertise provided a framework for the recommendations on technology. Although much information about the chemistry of chemical warfare agents is not readily available, several recent reviews about destruction of chemical warfare agents have been published.[3], [4] Much work has been done on chemical decontamination and much of the recent work has been directed to development of decontamination solutions that are not themselves harmful to the soldier or equipment. But this requirement for selective decontamination chemistry does not apply to chemical neutralisation of chemical warfare agents in munitions and some older, very effective recipes for chemical agent destruction may be useful in treating non-stockpiled materials. As the following outline shows, effective chemical recipes exist for detoxifying chemical agents. A complete destruction technology, of course, must also treat the detoxified solution.

An Outline of Chemical Agent Decontamination

The paper by Yang et al. [5] is a concise guide to decontamination chemistry and the following remarks are based on it.

GB and GD dissolve in water and hydrolyse under acidic and basic conditions. VX, however, forms a basic solution and becomes less soluble as the pH rises; consequently a reaction medium at low pH is desirable. HD has low solubility in water - a film of polymer forms at the mustard/water interface, hindering transport into solution.

Bleaches react vigorously with pure and thickened chemical weapon agents - both nerve agents and mustard. Superchlorinated bleaches [5]detoxify G agents and react well with VX at low pH. G agents also are detoxified rapidly by alkali bases (e.g., NaOH). DS2[6], developed after World War II, is also very effective against nerve agents and mustard.

Other strong oxidisers detoxify chemical weapon agents, but may be selective. Aqueous Oxone (a commercial preparation of KHSO5) dissolves VX and oxidises it at the sulfur; it is also very effective against mustard. Oxone is not, however, sufficiently active against GB and GD for its use to be recommended on these agents.

Biodegradation of hydrolysed mustard has been carried out with degradation of 97% of the carbon containing compounds. The organisms were, however, killed by untreated mustard.

Arsenicals

Organic arsenical agents pose a difficult problem because the arsenic remains toxic when the organic portion of the molecule is reacted to non-toxic products. A variety of arsenicals was developed during and after World War I and their treatment in the field depends on their differing chemistries. For example, Clark I and II [diphenylchloroarsine and diphenylcyanoarsine] hydrolyse slowly in water unless they are finely divided. Adamsite [diphenylaminochloroarsine], as a solid, forms an oxide coating in water and hydrolyses very slowly. Lewisite [dichloro(2-chlorovinyl)arsine] hydrolyses faster than the preceding compounds, but has low solubility in water. The German success in recovering arsenic from incinerator scrubber water by precipitation as the arsenate suggests that a similar method could be applied to chemically treated agents containing arsenic. The precipitated arsenic salt could be removed from the supernatant liquid which could then be treated in subsequent steps (supercritical water oxidation, etc.). The removed arsenic may not require disposal; demand for arsenic as a wood preservative by the US was 22,000 metric tonnes in 1991.[7]

Aerial bombs were filled with mustard or nerve agent, the largest of which contained about 320 litres of nerve agent. They were mostly under substantial internal pressure: nerve agent, because of its normally high vapour pressure and the high desert temperatures; mustard because it and the trace acids present in the Iraqi weapons apparently reacted with the metal containers and produced hydrogen. Bombs were drilled to relieve the pressure and their outside decontaminated with German emulsion. [8] They were then drained, filled with a mixture of isopropyl alcohol and sodium hydroxide, and left for a day. Usually a charge was exploded to rupture the container and ignite the alcohol (both Canada and the UK have considerable experience with cutting and penetrator explosive charges). The caustic alcohol solution did not dissolve polymerised mustard, but it was destroyed by the combustion.

For artillery shells, a shaped charge was suspended in the burster well, the cap replaced, and the charge fired. The contents were then removed using a vacuum hose. About 60% of the mustard was recovered; the remainder was polymerised. Mustard removed from these items was mixed with benzene, toluene and diesel fuel and burned in an incinerator. Furnace temperature was 1100 ^oC and residence time was about 5 seconds. The furnace proved to be very efficient with <15 ppm CO emitted; good HCl and fair SO₂ scrubbing was achieved in the pollution abatement system. Nerve gas has a relatively high vapour pressure and achievement of the much higher levels of containment needed to handle these compounds was not practical for Iraq's incinerator; therefore the nerve gas was hydrolysed with excess base. This created a volume of waste five times that of the nerve agent; it was reduced by evaporation of the water from concrete lagoons under the desert sun. The salt residue was then sealed under a concrete cap.

Rockets, unlike items described above, had energetic material aboard and the agent containers were under considerable internal pressure. Drilling to empty them involved too much risk; so they were destroyed using a fuel/air explosion.

Desirable support infra-structure for activities of this sort includes: buildings; filtered ventilation system; effluent treatment; heating and cooling; facilities for changing clothes, decontamination and medical treatment; experienced personnel.

Russia [9]:

Since operation began in 1980, 73 tons of concentrated chemical weapon agents and 600 tons of contaminated material have been destroyed. The cost estimate for sulfur mustard is about 100 DM/kg. This cost is dominated by the individual processing required by numerous non-uniform and corroded recovered items.

1.

 chemical agent identification sets

2.

 "small" chemical weapon burials - no explosives, less than 100 items

3.

 small chemical weapons burials with explosives

4.

large chemical weapons burials

5.

former chemical weapons test ranges.

Non-destructive analysis is used on every discovered munition. Currently the technique, judged very successful, is neutron spectroscopy. The PINS [11] instrumentation used by the Army has not yet had a false positive or negative identification and requires about 10 minutes to collect sufficient data.

Agent identification kits contain dilute agents in glass ampoules. A specially esigned Raman spectroscopy apparatus is used nondestructively to determine the contents of the ampoules.

The "Rapid Response System", planned for the field in 1995, is a glove box on a truck. It is brought to the site where recovered items undergo external decontamination, are nondestructively inspected, and treated. This system is part of a planned transportable "Munitions Management Device Family".

Effective treatment methods are especially needed. A safe, environmentally acceptable technology is not yet available to take to the burial sites. Chemical neutralisation is attractive because of the perceived short development time. Recipes include monoethanolamine/water at 65 ^oC or 1,3-dibromo-5,5-dimethylhydantoin at room temperature for mustard, and the "Canadian decontamination" solution (KOH/methanol) for GB. Irreversible destruction is required, so even neutralised materials will have to be treated subsequently.

Research is especially needed on decontamination recipes for VX, the chemical characterisation of neutralisation reactions (kinetics, product identification), and the toxicology of "old chemical agents" that have been degraded in soil.

Because of their rapid hydrolysis, nerve agents are not perceived to be a problem in soil or ground water, and neither the UK nor Canada has detected mustard in ground water under their firing ranges. Nevertheless, in judging these results, one must consider the level of analytical capability available for these measurements, their sensitivity, not only to agent, but also to degradation products.

Site Contamination by Energetic Materials in the US:

Explosives can be ranked according to sensitivity: "primary" explosives include lead azide and fulminate of mercury, "high" explosives include TNT, RDX, HMX and picric acid, "low" explosives include black powder, solid propellants, pyrotechnics.

Ground water contaminated with explosives is a major problem. Near term treatments include reactions with UV/ozone, peroxide/ozone, and adsorption. Biodegradation of these materials is not yet a mature technology: there are apparent "dead ends" in the degradation chain short of complete mineralisation; these dead ends account for about 80% of the material in the best results to date.

Explosive materials may become more bound and less accessible to remediation in soil with time. Treatments of contaminated soils (ranked from presently available to increasingly distant possible technologies) are: incineration, physical separation, composting, bioslurry, in-situ biodegradation, chemical extraction, electrokinesis. Physical separation refers to adoption of techniques from the mining industry that depend on selective adsorption of the contaminant by different soil fractions; so one can separate fractions enriched in explosives by screening for size, airjet separation, etc.

The Army has used incineration of contaminated soil on a large scale: nearly 100,000 tons were incinerated at the Louisiana Ammunition Plant; costs were about $300/ton.

The number of countries having active chemical weapons programs is estimated at 20-25; those having problems with non-stockpiled materials at 30 with millions of these items world-wide. The Chemical Weapons Convention requires their disposal.

The non-stockpiled items include: modern chemical munitions with and without explosives, bulk chemical agents, old and abandoned chemical munitions, buried munitions, and munitions washed up on beaches. Obviously, because of the wide range of possible locations and conditions of these items, the potential for risk to people and to the environment is enormous.

Based on the presentations during the Session on Current Field Methods, workshop participants developed five representative scenarios intended to describe a range of important problems against which to test munitions disposal technologies. These scenarios are shown in Table 2.

Table 2: Representative Chemical Weapon Destruction Scenarios Developed by Workshop Participants
 

Session 3: Chemical Weapon Destruction Technologies

1. Destruction at high temperatures[12]

Methods employing high temperatures include: incineration, pyrolysis, plasma torch and molten metal. These technologies have the potential for total destruction of all wastes in one apparatus and humankind has considerable experience in their use. One high temperature method, incineration, however, has a poor public image and these methods do put severe demands on materials of construction.

Evaluation of these methods requires consideration of decomposition reaction kinetics. Thermodynamics of this process favour decomposition; therefore failures in practice must be due to kinetics. These include the rates of mass and heat transfer as well as elementary chemical reaction rates and, in fact, problems with transfer processes have dominated in most failure cases.

There are a large variety of processes that initiate decomposition of organic compounds at high temperatures. For simple hydrocarbons (e.g., the usual fuels) bond breaking is the most likely process. With the introduction of heteroatoms and increasing molecular size, low energy (low temperature) decomposition paths to form stable molecules may be very important.

Bimolecular processes also contribute to destruction of organic compounds. These low activation energy processes are attacks by radicals: OH. and H. are important in incineration, H. is important in pyrolysis, ions and electrons are present in plasma processing. For many compounds, bimolecular processes are the primary mode for destruction. If, however, the target molecule is thermally labile, it will decompose at low temperatures without attack from radicals.

For thermally labile compounds (including nerve agents and, possibly, mustard), pyrolysis (thermal treatment without oxygen) alone can destroy organic compounds. Compared to incineration, for the same amount of materials, pyrolysis requires smaller reactors, no mixing, and lower temperatures. Pyrolysis may, however, produce toxic products. If incineration is used, pyrolysis is the first step in the multi-stepdestruction process.

Incineration is a widely used and proven technology with a long history of research and development. Much is known about the details of the destruction process and conditions for effective operation are well established. This improved understanding has been developed during the past few years and, because of facilities improperly operated in the past, incineration suffers from a poor public image.

The Plasma Torch employs an electric field to generate a plasma with temperatures of the order of 10,000 ^oC. Although electrons and ions are present, they neutralise quickly and do not appear to participate in the reaction. Evidently the torch functions as a very high temperature heater. It can be used to process wastes with inorganic contaminants not suitable for an incinerator; the higher temperatures enable vitrification of these components, aiding in eventual disposal.

Molten Metal systems use a heated bath, typically of Fe or Ni, and an off-gas treatment system. Possible problems include carry over of particles in the exhaust stream and life of the refractory materials used to line the vessel. Treatment of wastes using an enclosed molten metal system includes the possibility for the production of useful chemicals, such as syngas (CO + H2), from the decomposition chemistry in the bath[13]. This technology[14] may also find use for treatment of wastes containing metals; for example arsenic may be captured.

Military toxic wastes can be destroyed to any reasonable level of completeness at easily accessible temperatures using a wide variety of technologies. Failures are not due to chemical reaction kinetics, but to the physical processes of mixing and heat transfer - reactor design. Operation at higher temperature (above a certain minimum) may not be better if it is purchased at the expense of good mixing.

2. Hydrogenation

Unlike incineration, which oxidises wastes, hydrogenation reduces them. A hydrogenation reactor under standard conditions runs at about 1 bar with three fold excess hydrogen and a dwell time of 1-10 seconds. The reactor temperature for halogenated hydrocarbons is about 850 ^oC.

An example of a reduction reaction is: chlorobenzene + H2 at 900 ^oC → 99.96% to benzene + HCl. For the bond C-X, there are no X groups known that do not participate in this reaction; therefore the reaction has very broad application. For halogenated hydrocarbons, the gaseous halogen acid can be removed with water and recovered separately from the hydrocarbon product. Currently Royal Schelde in the Netherlands has built a mobile unit with a capacity of 600 tons/year.

Hydrogenolysis with standard catalysts enables reaction at lower temperatures, but the catalyst is sensitive to poisoning by heteroatoms (e.g., S) and deposition of soot. Alternatively one can pack the reactor with activated carbon to enable complete reactions at significantly lower temperatures (T < 600 ^oC). The carbon packing does eventually deactivate, so this method may find best use as a subsequent treatment following removal of most of the HX product.
 

Possible sources of hydrogen include syngas (CH4 + steam → CO + 3H2) and methanol → CO + 2H₂ (at 800 ^oC). Methanol can be put directly into the hydrogenation reactor.

For chemical warfare agents, it appears that hydrogenolysis of mustard should be effective with products of H2S and HCl. Studies of organophosphorus nerve agent simulants[15] show variation ineffectiveness from compound to compound.

3. Supercritical Water and Wet Air Oxidation

These methods, also called "hydrothermal processing"[16], refer to oxidative reaction of wastes in water at elevated temperatures. Supercritical reactions occur above the mixture critical point (often around 500 ^oC and 250 bar) so that the mixture is single phase. WAO is carried out below the critical point. These technologiesare becoming mature: commercial, mobile SCWO reactors with capacities of 400 L/day are commercially available and a WAO in-ground system is now in testing[17].

Feed preparation and delivery: wastes in dilute, aqueous solution can be introduced directly into the reactor. Insoluble liquids and solids may be treated and introduced as slurries.

Oxidant: compressed air is the cheapest source of oxygen, but carries the penalty of 80% inert nitrogen. Liquid oxygen can be cryogenically pumped and vaporised into the reactor and may be economical for large systems. Hydrogen peroxide is more expensive but is relatively safe to handle.

Reactor designs: the pipe flow reactor is simplest but may be more subject to plugging by salts and erosion by solids. The vertical vessel is most convenient for salt/solid separation from the reaction medium and may be best for high solids feeds or when neutralisation of the waste is necessary (e.g., pretreatment of chemical weapon agents).

A transportable high pressure unit has been designed and built at Los Alamos National Laboratory for explosives disposal. The reactor is a 3mm inner diameter, 17 meter long tube with a capacity of 400 L/day. It is made of Inconel 625. Noble metal liners can be used for neutral to basic feed solutions and Ti may be used for acids. Liners are not currently being used.

Explosives decompose rapidly in water above 200 ^oC to small, water soluble organic and inorganic molecules. Subsequent reactions with oxygen at higher temperatures take these intermediate products to carbon dioxide and other inorganic products.

Several methods were explored to prepare solid explosive for the reactor. A solution in organic solvents has the disadvantage of solvent handling. Preparation of water slurries requires use of water jets or grinding which are potentially dangerous. The preferred method, hydrolysis at about 90 ^oC in aqueous NaOH or NH₄OH, leads to non-energetic, soluble products suitable for subsequent treatment by hydrothermal processing. Dissolution of several kg chunks of solid energetic material loaded at 1 g per 10 ml of 2M NaOH and stirred at 90 ^oC until no solid remains requires a few hours. It appears that each nitro group on the energetic materials requires an equivalent of base.

General Atomics Corporation is building a 4000 L/day SCWO mobile reactor for propellants and chemical weapon agents. Testing is planned for autumn of 1994. They report having successfully treated GB, VX and mustard on the laboratory scale[18]. The cost to build a unit running 20 L/min is $2,000,000.

Hydrothermal processing can be performed safely; the stored energy and volume of waste in the reactor are relatively small. Reactor components are commercially available and units can be compact and transportable.

4. Dry HCl Gas, Pyrolysis

Workers in France have reacted GA and GB with dry HCl. Products are greatly reduced in toxicity, but this treatment on VX leads to a very toxic product. Similarly, this method is effective on some arsenicals. The use of HCl is recommended because it is cheap, available, gives light by-products, can be used without solvent, and the reaction can be controlled.

French workers have also investigated the use of the munition case as a reaction vessel by exposing VX munitions to low intensity pyrolysis. Studies of VX in glass vials shows destruction of VX over periods of hours at 200 ^oC and minutes at 245 ^oC. Partial analysis by gas chromatography/mass spectrometry has identified over 80 products before the study was stopped; these products are a factor of 103 less toxic (tests on rats) than VX. For a filling of 90% of VX, the pressure may reach 35 atm at 245 ^oC. At room temperature, there is no overpressure. Thickened VX is destroyed in the same way. Thermolysis of GB is easy in batch at 145 [[ordmasculine]]C or may be handled in a flow reactor with removal of non-toxic products (probably at higher temperature).

Thermolysis of GD in munitions is easy: 20 min at 150 ^oC for a filling of 90%. The pressure of the products is 11 atm at 150 ^oC, and 4 atm at room temperature. Thickened GD is destroyed under the same conditions. These materials can be handled in a flow reactor with removal of relatively harmless products. Products have been identified using nuclear magnetic resonance.

5. Metal and Metal Oxide Catalysis

Finely divided (nano-crystalline) metal oxides[19] have been shown to mediate the mineralisation of chemical weapon agent simulants by oxygen and peroxide. These materials have a large surface/volume ratio with, presumably, enhanced surface absorption or intercalation. Their small size and open structure enables a large capacity for oxidiser uptake. They are semiconductors and are activated by light.

Materials that have exhibited these properties include the oxides of Zn, Ti, Fe, Mn, Ag, Sn, Zr, Nb and the sulphides of Fe and Mo.

Studies with malathion in aqueous suspensions of TiO₂ have shown degradation under relatively mild conditions: slow degradation occurs in air at 70 ^oC; reaction rates increase with more powerful oxidisers (air peroxide persulfate periodate). Addition of Fe⁺³, which coats the TiO₂ particles, increases the reaction rate.

The Swiss have used these methods on groundwater contaminated by explosives manufacture with initial total organic carbon of 12,000 ppm.

The high activity of Fe⁺³ suggests its use on old munitions to dissolve the case corrosively and subsequently to catalyse the oxidative destruction of the chemical weapon agent and explosives.

6. Silver(II) Electrolysis

Developed by AEA Technology[20] to destroy nuclear processing wastes: spent solvent, ion exchange resins, cellulose tissue, rubber gloves. Workers have demonstrated destruction of tributyl phosphate - a nerve gas simulant - and, at Porton Down, of GA, GB, VX, mustard, and thickened mustard. A simulated rocket containing nerve agent (VX and 2,4-dinitrotoluene in an aluminium capsule) was destroyed in 6 hr at 50 ^oC The precipitation of AgCl from agents containing Cl is a complication that may be solved by using a catalyst different from Ag.

The electrochemistry exploits the strong oxidising power of Ag(Il) and is carried out in HNO,. A series of reaction steps causes the oxidation of water: 2 AgNO₃⁺ + 3 H2O ₂ Ag⁺ + 1/2 O₂ + 2 H₃O⁺ + 2 NO₂^-

Intermediate steps in this reaction create reactive species that oxidise the waste. C goes to CO₂, H to H⁺, S to sulfate, P to phosphate, N to nitrate, halogens to X^-.

The overall anode process of interest is: C + 2 H₂O CO₂ + 4 H⁺ +4e^-

The principal overall cathode process is: NO₃^- + 3 H⁺ + 2 e^- HNO₂ + H₂O

The electrochemical cell is divided to prevent cathode products interfering with oxidation at the anode.

Advantages of this technology include: relatively low temperature, operation at or below atmospheric pressure, ability to stop the reaction nearly immediately after power to cells is stopped, small amount of stored waste material in cell, the same operating conditions can be used for a wide range of waste materials, little volatilisation of intermediate products.

precipitation by Fe³⁺ or Ca²⁺ of insoluble arsenate salt,

Containment[21].

Other Technologies:

Hot water technologies may be applicable if adequate supplies of water are available. These methods must be tested on mustard and Lewisite.

Notes:

Metal oxide oxidation of the chemical agents may have the advantage of easier recovery of the arsenic and less water required than the scrubbers in an incinerator. Cryofracture followed by incineration could be effective but requires liquid nitrogen in a remote location. Development of improved methods to remove fuses from old munitions are, of course, applicable to all scenarios involving fused munitions.

Unsuitable Technologies:

The high concentrations and toxicity, especially of the arsenic compounds, appears to rule out bioremediation.

Scenario 5: Polymerised or thickened mustard

in 100 rounds of explosively configured munitions found in the centre of a major city. Two weeks allotted for disposal. After primary detoxification at site, removal for final treatment is permitted.

First Choice of Technology:

Evacuate area. Examine munitions non-destructively (X-ray, PINS). If fused and unstable, blow it up in a containment vessel. All handling must be by remote control. If the munitions has no fuse, open it under aqueous NaOH using a water jet or explosive cutting tape. Deactivate mustard on-site in NaOH at 90 ^oC or in hypochlorite using ultrasonic agitation to free mustard from the munition shell. Move containment unit to a remote location for decontamination.

Resources Required:

Containment units for detonations.

Second Choice of Technology:

Open munitions that have been rendered safe at both ends by mechanical or electrochemical cutting. Destroy the gelled contents and energetic material by silver(II) electrolytic oxidation.

Rationale:

The entire procedure must be done in a containment unit in case of accidental detonation. The silver process may be slow, but several units will speed up the operation.

Resources Required:

A scaled up silver(II) based system with containment.

Third Choice of Technology:

Steam reforming with 500 ^oC steam is already used for decomposition of biomedical waste containing rubber gloves and other plastic materials. This technology should be further investigated for its ability to deal with thickened, gelled, or polymerised mustard.

Unsuitable Technologies:

Incineration is unsuitable because it is not likely to be possible to bring a transportable incinerator and carry out the necessary operations in a large city.

Notes:

It would be useful to know in detail the effects of cryogenic cooling on the energetic train, especially fuses, in munitions. There have been suggestions that cooling makes the secondary explosive more sensitive to detonation.

Summary of the Recommendations

A brief summary of the workshop recommendations is given in Table 3. The reader should remember that the recommendations were based on specific scenarios representative of actual experience. They are not, of course, complete. In the judgement of the participants, all the technologies examined at this workshop had significant promise for destruction of military toxic waste. The problems are so varied that a wide range of tools will be necessary for their proper solution.

Table 3: Summary of Workshop Recommendations for the Scenarios
 

Conclusions of the Workshop Participants

The technologies discussed at this workshop have great promise for managing destruction of non-stockpiled chemical weapons in a variety of situations. Tests against chemical agents, specifically, have shown the effectiveness of most of these technologies. Although more detailed basic understanding of the processes involved (e.g., rates of chemical reactions) is desirable, it appears that these technologies can be developed into systems ready for the field. The principal need now is for systems engineering studies to project destruction effectiveness, costs, and operating times required for full scale units.

The workshop participants judged that no one technology is likely to be the best choice for all, or even most, of the scenarios - each technology has characteristic advantages and disadvantages. Protection of people and the environment should be the most important driver for the choice applied to a specific problem in the real world. Cost should be a secondary consideration but, because of the scale of the problem, is very important. Those situations where people are at risk will require more expensive disposal systems involving considerable containment of the munitions. Other situations can approached more simply and cheaply. It is important that disposal teams have a range of tools from which to choose the solution most suited to the problem.

As stated at the beginning of this report, the workshop concerned itself primarily with destruction by chemical and thermal processes and not very much with handling of munitions. But handling is, perhaps, the most difficult challenge.

Continued research is necessary to maximise the predictive power of the recommended engineering studies. In addition to the various processes involved in the methods presented in this report, other areas requiring further study include non-intrusive analysis, methods to remove agent from munitions (decanting), safe transport methods, identification of agent degradation products in the environment, detection and monitoring at occupational health levels, and the environmental impact of agents and their degradation products

Relief from Secrecy

A vast grey literature exists on the properties, chemistry, etc. of chemical agents. Much of this remains either unavailable or accessible only with great effort. Efforts like this workshop would be aided enormously by access to this literature. The Chemical Weapons Convention calls for the establishment of data banks and all member states have been asked in January 1994 for documents. It is vital to the development of an effective program for destruction of chemical munitions, stockpiled and non-stockpiled, that nations declassify their documents on chemical weapons and release them and that the relatively few laboratories that have studied these materials publish their results. We encourage readers of this report to support this important effort. Documents should be sent to Dr. Santesson (for the address, see the list of participants, following).

NATO Advanced Research Workshop: "Destruction of Militarily Toxic Materials"

Carlton Flower Hotel, Naaldwijk, The Netherlands, 22-27 May 1994

Sunday, May 22

17:00 Introduction of the ARW Participants

20:00 The Objectives of the ARW... The Organisers

Monday, May 23

Session 1: Current Field Methods .. ..J Santesson (The Hague), Leader

09:00 R Manley (The Hague): Lessons from the Destruction of Chemical Weapons in Iraq

10:00 O Korobeinichev (Novosibirsk): Destruction of Chemical Weapons in Russia

11:00 J. Cullinane (US Army): Clean-up of Explosives on Military Bases

14:00 G. Moes (Prins Maurits Lab): Destruction of Mustard Gas in the Tropics

15:00 H Martens (Munster): Incineration of Chemical Weapons in Germany

16:00 L Jackson (US Army), Examples of Nonstockpile Items in the US, Plans for Disposal

20:00 Session 2: Development of Destruction Problem Scenarios.... R Manley, Discussion Leader (Toxic Materiel Types, Local Conditions, Available Resources )

Tuesday, May 24

Session 3: New Toxic Waste Destruction Technologies - High, Medium, Low Temperature R. Seiders (US Army) Leader

09:00 W Tsang (NIST): Incineration, Pyrolysis (Molten Metal, Plasma Arcs, etc.)

10:30 J Tester(MIT): Supercritical Water and Wet Air Oxidation: Capabilities and Requirements

11:15 S Buelow (Los Alamos): Supercritical Water - Experience with Military Materials

14:00 M Grätzel (Lausanne): Metal Oxide Mediated Oxidation of Toxic Materials

14:45 R Soilleux (Porton Down): Silver Oxidation of Chemical Weapon Agents

15:30 D Froment (Vert-le-Petit): Treatment with HCl

16:15 R Louw (Leiden): Hydrogenation of Chemical Weapon Agents

Wednesday, May 25

Working Groups

10:00 Formation of Working Groups, Guidance from Organisers

10:30 Working Group Sessions - Match Scenarios with Technologies

15:00 Reports of Working Groups/Discussions

Thursday, May 26

09:00 Working Groups Develop Recommendations Throughout the Day

Friday, May 27

09:00 Final Reports/Discussion from the Working Groups

11 :00 ARW Summary ....The Organisers

Workshop Participants

NATO Advanced Research Workshop: "Destruction of Militarily Toxic Materials"

Carlton Flower Hotel, Naaldwijk, The Netherlands, 22-27 May 1994

Director:

Dr. Robert W. Shaw, Associate Director of Chemical and Biological Sciences
US Army Research Office, Research Triangle Park, NC 27709, USA
Int +1-919-549 4293, fax int +1-919-549 4310. SHAW@ARO-EMHI.ARMY.MIL

Co-Organizers:

Professor Joseph Bunnett
Thimann Labs, University of California, Santa Cruz, CA 65064, USA
Int +1-408-459 2261, fax int +1-408-459 2935, BUNNET@CHEMISTRY.UCSC.EDU

Dr. Oleg Korobeinichev, Head of Laboratory of Kinetics of Combustion
Institute of Chemical Kinetics & Combustion, Russian Academy of Sciences, Novosibirsk 630090, RUSSIA
Fax int +7-3832-352 350 (or int +7-3832-352 366), KOROBEIN@KINETICS.NSK.SU

Dr. Johan Santesson, Technical Cooperation Officer
The Provisional Technical Secretariat of the Preparatory Commission for the Organization for the Prohibition of Chemical Weapons, Laan van Meerdervoort 51, NL-2517 AE, The Hague, NETHERLANDS
Int +31-70-376 1773, fax int +31-70-360 0944, ICA Division, OPCWL

Participants:

Dr. Steven Buelow, Project Leader, Hydrothermal Processing
Los Alamos National Lab, MS J567, P O Box 1663, Los Alamos NM 87545, USA
Int +1-505-667 1178, BUELOW@CLS.LANL.GOV

Prof Alexander Levanovich Chimishkyan, Chair in Organic Chemistry and Technology
Department of Chemical Engineering, D Mendeleev University of Chemical Technology, 9 Miusskaya Sq. Moscow 125190, RUSSIA
Office: int +7-095-496 60 58, fax int +7-095-200 4204 or int +7-095-496 9264, home: int +7-095-465 9672, fax int +7-095-919 5507

Dr. John Cullinane, Program Manager, Environmental Restoration Research
US Army Waterways Experiment Station, 3903 Halls Ferry Road, Vicksburg, MS 39180-6199, USA
Int +1-601-634 3723, fax int +1-601-634 3833, CULLINM@.EXl.WES.ARMY.MIL

Dr. Daniel Froment, Chief of the Chemical Group
Departement des Recherches Etudes et Techniques, Etablissement Technique, Central de L'Armement, Centre d'Etudes du Bouchet, B.P. No. 3, 91710 Vert-le-Petit, FRANCE

Prof Michael Gratzel
Swiss Federal Institute of Technology, Institute of Physical Chemistry, Lausanne, CH-1015, SWITZERLAND
Int +41-21-693 3112, fax int +41-21-693 6100

Col Louis M Jackson, Asst. Deputy for Chemical/Biological Matters,
Office of the Assistant to the Secretary of Defense (Atomic Energy) The Pentagon, Rm 3C128, Washington, DC 20301-3050, USA (previously US Army Program Manager for Nonstockpile Chemical Materiel)
Int+1-703-695 1097, fax int +1-703-695 7596, LJACKSON@DAN.APGEA.ARMY.MII.

Dr. Peter Lockwood, Director,BR> Biological Defence and Medical Development Program National Defense Headquarters, 305 Rideay Street, Ottawa, Ontario, CANADA KIA 0K2
Int +1-613-995 2193, fax int +1-613-996 5177, Peter.Lockwood@CRAD.DND.CA

Dr. Robert Louw, Professor of Environmental Chemistry
Center for Chemistry and the Environment, Gorlaeus Laboratoria der Rijksuniversiteit te Leiden, Leiden University, P.O. Box 9502, 2300 RA Leiden, THE NETHERLANDS
Int +31-71-274289; fax int +31-71-274488

Dr. Ron Manley, Head, Chemical Weapons Branch
The Provisional Technical Secretariat of the Preparatory Commission for the Organization for the Prohibition of Chemical Weapons, Laan van Meerdervoort 51, NL-2517 AE, The Hague, NETHERLANDS
Int +31-70-376 1747, fax int +31-70-360 0944

Dr. Herman Martens, Head of Chemical Defense Division
Wehrwissenschaftliche Dienststelle der Bundeswehr für ABC-Schutz, Postfach 1142, 29623 Munster, GERMANY
Int +49-5192-136 400; fax int +49-5192-136 355, int +49-261-400 2748

Prof Marian Mikolajczyk, Director
Centre of Molecular & Macromolecular Studies, Polish Academy of Sciences, Sinkiewiczq 112, 90-363 Lodz, POLAND
Int +48-42-815 832, fax int +48- 42-817 126

Dr. Giorgio Modena, Professor of Organic Chemistry
Dipartimento Di Chimica Organica, Universita Degli Studi, Via Marzolo 1, 35131 Padova, ITALY
Int +39-49-831 235; fax int +39-49-831 222

Mr. Ger Moes
Prins Maurits Laboratory, Postbus 45, NL-2280 AA Rijswijk, THE NETHERLANDS
Int +31-15-842 842, fax int +31-15-843 991

Dr. Valentine Parmon, Vice Director, Boreskov Institute of Catalysis
Institute of Catalysis, SB Russian Ac Sciences, Novosibirsk, 630090, RUSSIA
Fax int +7-3832-355 756

Dr. Reginald Seiders, Chief of Organic Chemistry and Surface Science
US Army Research Office, Research Triangle Park, NC 27709, USA
Int +1-919-549 4365, fax int +1-919-549 4310, SEIDERS@ARO-EMH l .ARMY.MIL

Dr. Richard Soilleux, Head of Safety and Environmental Matters,
Chemical & Biological Defence Establishment Porton Down, Salisbury, Wilts. SPEW 0JQ, UK
Int +44-980-610 211, fax int +44-980-611 777

Dr. Jefferson Tester, Professor of Chemical Engineering and Director, Energy Laboratory
Massachusetts Institute of Technology, Energy Laboratory E40-455, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
Int +1-617-253 3401, fax int +1-617-253 8013, TESTERL@MIT.EDU

Dr. Wing Tsang, Research Chemist
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
Int +1-301-975 2507, fax int +1-301-926 4513

Mr. Nigel Warren, Silver II Process Project Manager AEA Technology, D1218 Dounreay, Thurso, Caithness KW14 7TZ, UK
Int +44-847-802 121 ext 2853, fax int +44-847-802-850

1 References to Chemical Weapons will follow the nomenclature: GA is Tabun (O-ethyl dimethyl-amidophosphoryclyanide), GB is Sarin (isopropyl methylphosphonofluoridate), GD is Soman (pinacolyl methyl phosphonoflluoridate), GF is cyclohexyl methylphosphonofluoridate, VX is O-ethyl S-diisopropylaminomethyl methylphosphonothiolate, mustard (HD) is bis(2-chloroethyl)sulfde.

2. Alternative Technologies for the Destruction of Chemical Agents and Munitions. 1993. National Research Council Commission on Engineering and Technical Systems, 2101 Constitution Avenue, Washington, D.C. 20418;U.S. Army's Alternative Demilitarization Technology Report for Congress. 11 April 1994. Program Manager for Chemical Demilitarization, Department of the Army, Aberdeen Proving Ground, MD 21010-5401; Chemical Weapons Destruction, Advantages and Disadvantages of Alternatives to Incineration. March 1994. US General Accounting Office, Washington, DC, GAO/NSIAD-94-123.

3. Yang, Y-C., Baker, J.A., Ward, J.R. 1992. Decontamination of Chemical Warfare Agents. Chem. Rev. 92:1729-43.

4. MacNaughton, M.G. and Brewer, J.H. 1994. Environmental Chemistry and Fate of ChemicalWarfare Agents. Final Report SwRI Project 01-5864. Southwest Research Institute, San Antonio, Texas.

5. A typical bleach is 5 wt % NaOCI in water. Superchlorinated bleaches are mixtures of Ca(OCI)CI, Ca(OCI)₂, CaO. These materials can be buffered to improve storage life.

6. 70% diethylenetriamine, 28% ethylene glycol monomethyl ether, 2% NaOH.

7. Mercury and Arsenic Wastes: Removal, Recovery, Treatment and Disposal. 1993 report for the USEPA, Noyes Data Corp, New Jersey.

8. The C-8 "German Emulsion" consists of 8% high test hypochlorite [Ca(OCI)CI = Ca(OCI)₂], 15% tetrachloroethylene, 1% emulsifer (e.g., Marlowet), and water.

9. These remarks describe proposed Russian methods for dealing with stockpiled as well as non-stockpiled munitions.

10. Survey and Analysis Report. Nov 1993. Program Manager for Nonstockpile Chemical Material, U.S. Army Chemical Material Destruction Agency, Aberdeen PG, MD 21010-5401.

11. The "Portable Isotopic Neutron Spectroscopy" system was designed and built by Idaho Nuclear Engineering Laboratory specifically for non-destructive analysis of chemical munitions. It detects characteristic gamma rays from nuclei activated by neutrons. The neutron source is ²⁵²Cf; the detector is liquid nitrogen cooled Ge.

12. The technologies discussed are arranged roughly in order of decreasing operating temperature.

13. Notice that complete oxidation does not occur in the molten metal bath.

14. Molten salt combustion has been studied for destruction of organophosphorus agents and mustard and reported to be effective. Alternative Technologies for the Destruction..(ref2), pp 171-174.

15. Thermal and Acid Catalyzed Conversion of Organic Phosphorus Compounds. 1993. Lijser, H.J.P., Mulder, P., and Louw, R., Chemosphere, Vol. 27, No5, pp 773-8.

16. Harradine, D. M., et al. 1992. Oxidation Chemistry of Energetic Materials in Supercritical Water. Los Alamos LA-UR-92-1212, Presented at AIChE Annual Mtg., Miami. Rice, S.F., et al. Supercritical Water Oxidation of Coloured Smoke, Dye, and Pyrotechnic Compositions. 1994. SAND94-8209, Sandia National Laboratories. Tester, J.W. et al. Supercritical Water Oxidation Technology. Process Development and Fundamental Research. 1993. in Emerging Technologies in Hazardous Waste Management III, ACS Symp. Ser. 518, 35-76.

17. A municipal sludge treatment plant using hydrothermal processing at relatively low pressures (100 bar) is undergoing testing at Apeldoorn in the Netherlands. The planned annual capacity is 25,000 tons of sludge solids. The company, VerTech, calls the process "aqueous phase oxidation". A very long vertical reactor is sunk in the earth thus generating the pressure required from the liquid column. VerTech Treatment systems b.v., Baarnsche dijk 12, P.O. box 292, 3740 AG Baarn, The Netherlands.

18. Remaining agents, if any, were below the detection limit which enabled setting the Destruction Removal Efficiency at >99.9999% (six 9's) or higher.

19. Grätzel, M. 1991. Complete Destruction of Agents in Microheterogeneous Soutions and on Oxide Films. Presented at the US Army Chemical Research Development and Engineering Center Scientific Conference on Chemical Defense Research, Aberdeen Proving Ground, MD. Fox, M.A., et al. 1990. Photocatalytic Decontamination of Sulfur-containing Alkyl Halides on Irradiated Semiconductor Suspensions. Catal. Lett. 5, 369.

20. AEA Technology, Thurso, Caithness, Scotland, UK, KW14 7TZ; The Low Temperature Destruction of Organic Waste by Electrochemical Oxidation. 1990. Steele, D.F. Et al., Trans I Chem E, Vol. 68, Part B, pp.115-21.

21. A suggestion was made to explode the munitions underground to provide containment. But the Chemical Weapons Convention requires verification of munition destruction - difficult if underground explosions are used.