Treatment of Chemical Weapons

Treatment of PCBs, Dioxins and Furans

Treatment of Explosives 

Treatment of Chlorofluorocarbon Refrigerants and Halons

Solvated Electron Chemistry 
A Versatile Alternative for Waste Detoxification 

Frequently Asked Questions (FAQ)

Patents Held

Summary

Commodore Solution Technologies, Inc. has developed an innovative total systems approach to environmental remediation, which utilizes a patented (Abel, 1992) chemistry called Solvated Electron Technology (SET ^TM). Solvated electron solutions are some of the most powerful reducing agents known. Formed by dissolving alkali and alkaline-earth metals in anhydrous liquid ammonia to produce a solution of metal cations and free electrons, solvated electron solutions are capable of providing unique reductants of great activity. They provide a highly useful mechanism for the reductive destruction of many organic molecules and are extremely effective in the dehalogenation of halogenated organic compounds. Commodore has received a nationwide EPA operating permit for the non-thermal destruction of PCBs in soils, oils, surfaces and solid materials using this process. The permit further allows for the recycle of treated PCB containing oils. The SoLV^TM process is a total solution that incorporates pre- and post- treatments, where necessary, for environmental clean up. It is applicable to a broad range of substrates including liquids, solids, soils, personnel protective equipment and job materials. Commodore has successfully commercialized this technology. Equipment capable of treating 10 tons a day is currently in the field. This paper provides an overview of the technology and process. Individual case studies are available for specific examples where the process has been utilized.

Introduction

Functional organic compounds have proven to be some of the most difficult and expensive remediation challenges to face the environmental clean up industry. As a class, they represent some of the most toxic, environmentally persistent, and difficult-to-destroy compounds known. In the environment, materials such as pesticides, PCBs, dioxins, furans, PAHs, BTXs, explosives, chemical warfare agents, chlorofluorocarbons, and chlorinated solvents are deemed to pose a hazard to health and the environment, even when present in relatively small quantities. To meet today's stringent cleanup standards, vast quantities of materials such as soil, job equipment, adsorbents, process liquids, and building materials must be treated to remove contaminants that may be present in quantities measurable only in parts-per-million.

Other than landfill, commercially available remediation technology options are limited principally to thermal processes such as incineration; plasma arc, catalytic extraction, gas phase chemical reduction, and thermal desorption. These are undesirable due to generation of off gases such as dioxins. There is a need for a total system and cost effective remediation approach that can destroy contaminants while rendering the soil or other matrix materials non-hazardous.

The SoLV^TM process utilizes solvated electron solutions to destroy hazardous contaminants. In the process, contaminants are destroyed by a chemical reduction mechanism, whereby the functional organic compounds are converted to petroleum hydrocarbons and metal salts. In the case of a PCB molecule, the halogen atoms are stripped from the halogenated organic compound and converted to sodium chloride and the carbon skeleton is converted to high molecular weight hydrocarbons. The resultant remediated soil can be returned to its original location.

The application of this versatile chemistry to environmental matrices has been proven by Commodore to be a cost-effective approach for addressing environmental remediation issues. Further, the chemistry has been validated by an independent research group (Mackenzie, 1996).

BACKGROUND ON THE CHEMISTRY

Although the discovery was made in 1865 that sodium metal dissolves in liquid anhydrous ammonia to form a dark blue solution with some rather unusual properties, solvated electron solutions still remain an under utilized phenomenon to most chemists. Yet, solvated electron solutions are one of the more powerful reducing agents known. Solvated electron solutions, also referred to as dissolving metal solutions, are formed by dissolving alkali or alkaline-earth metals, including sodium, calcium, lithium, and potassium, in anhydrous liquid ammonia.

Formation of the solvated electron is believed to occur as illustrated in the following

Equation:

The solutions, which form rapidly when the metal enters the ammonia, are characterized by a deep blue coloration and an electrical conductivity approaching that of liquid metals. For convenience, the solvated electron systems are frequently regarded as solutions of the metallic cation and electrons, a concept supported by the results of a number of physical measurements (Jolly, 1965).

Halogens can be split from organic halides by solvated electron solutions, yielding quantitative amounts of the halogen anion. In fact, this procedure was employed as early as 1914 (Chablay, 1914) for the analytical determination of organic halogens. By properly controlling reaction parameters, it is possible, in the case of the alkyl and aryl halides, to direct the reaction pathway so that the fully substituted parent hydrocarbon and the metal-halide are the sole reaction products (Smith, 1968). For the case of aromatic material, the parent hydrocarbon can react further to produce high molecular weight oligomers (Vlieger, 1986). The chemistry of reaction of aromatic halides with solvated electrons has been extensively described in a thesis (Hudson, 1963).

In addition to halogens, many other organic molecules are reactive towards solvated electrons. Several review articles have appeared that addresses the broad application of the chemistry (Watt, 1950; Birch, 1950: Birch, 1958)^. Organic phosphorous and sulfur compounds such as pesticides and chemical warfare agents are known to be reactive to solvated electrons (Kennedy, 1972). It is also well understood that aromatic materials such as benzene and poly aromatic hydrocarbons are chemically reduced by the Birch reaction using solvated electrons (Birch, 1950).

Process Description

The SoLV^TM process is modular in nature. Commodore has developed several process variations depending on the nature of the material being remediated. The various modules are designed to be tailored to each particular remediation site in a manner such that the most cost-effective sequence is utilized. The SET^TM treatment module is the centerpiece of the process and is a critical component of each process. All equipment is mobile and able to be placed at the site, which eliminates the expense of transporting hazardous materials. Space does not allow the description of all the possible combinations of these modules. However, they generally include front-end modules that can remove water or extract the contaminants of interest. Next, the SET^TM treatment module is required to destroy the contaminants. Back end modules are available to recycle ammonia, pH adjust, concentrate or fix the reaction products depending on the specific needs of the client.

Commodore’s commercial L1200 liquid unit is shown in Figure I. Such a setup is applicable to materials like PCBs in oil, liquid pesticides or extracted contaminates.

This system consists of a sodium transfer station, which warms sodium cast in shipping drums to a liquid state, and then pumps the liquid to the solvator tank. This tank is filled with anhydrous ammonia from an ammonia storage tank. The sodium dissolves in the ammonia creating a solvated solution. This solution is discharged to a reactor vessel, where a volume of approximately 65 gallons of the solvated solution is maintained.

Contaminated liquid is pumped to the reactor vessel where organics are instantly destroyed. The conductivity of the solution in the reactor vessel is continuously monitored, and when it drops to 200 Mhos feed is stopped. The destruction reaction is very fast and is essentially diffusion controlled. Removing ammonia vapor controls the temperature and pressure of the vessel. This results in lowering the temperature of the vessel. The feed rate for this system is approximately 1,600 pounds of material per day.

After the reaction, the solution is then transferred to the separator tank using the natural vapor pressure of the ammonia as the motive force. In the separator, the ammonia is heated to approximately 125^o F, and is pumped in vapor form to a condenser for recycling in the process. This recycling is performed by a commercial refrigeration subsystem.

The treated material is discharged to a waste storage vessel. At this point, hazardous organics have been destroyed, and with pH adjustment, the product is suitable for on site or non-hazardous disposal.

Solid materials are processed as-is or first extracted followed by destruction of the extract in the liquid L1200 unit. When it is desirable to treat solids as-is, they are placed in a solids screw reactor (Commodore’s 10 ton per day S-10 unit, Figure II) in which the contaminated solid materials and liquid ammonia are mixed. The ammonia washes the contaminate from the substrate. After a brief period of additional mixing, sodium metal is added to the ammonia slurry by solid or molten addition. Electrons are freed from the sodium and they chemically destroy the contaminants. When the process is complete, ammonia is retained for re-use, and the treated solid is returned to the environment. Commodore also has a solids handling unit capable of treating drum quantities of solids or liquids. This treatment unit is Commodore’s S/4 treatment vessel. A photograph of the S/4 is given in Figure III.

Wet sludges require a water removal step prior to using SET to destroy the contaminant. Drying or using a pre-wash module accomplishes water removal. After the water is removed, the soil can be remediated. The back-end module involves ammonia removal followed by a simple pH adjustment. At this stage the material can be disposed in a non-hazardous waste landfill.

Contaminated Soils and Sludges

Commodore has experience working with a wide variety of soils and sludge. Nationwide EPA operating permits have been awarded to Commodore for these materials. Characteristics of soils, which can impact the SETTM chemistry, include loam, sand, silt, clay, humic material, pH, cation exchange capacity, particle size, water, and iron content. The SoLV^TM process has been engineered to accommodate this wide range of variables. Some soils can be treated as-is. Others require pre-or-post processing to effectively remediate them. Example processes include water removal, size reduction, washing, and pH adjustment.

The SoLV^TM process can be modified to deliver the targeted remediation level. Soils containing many different organic contaminates have been treated. These include PCBs, PAHs, chlorinated solvents, dioxins, furans, pesticides, hexachlorobenzene, BTXs, volatiles, and semi-volatiles. After treatment with the SoLV^TM process, treated soils pass all TCLP criteria for replacement or non-hazardous waste landfill disposal. Table I contains data from several projects. Small quantities of soil are treated in the S/4 treatment unit. Commercial quantities of the Harrisburg soil have been treated on site using the S-10 equipment. Exhibit III is a photograph of the S-10 on site at Harrisburg, PA. Airport. The Hawaii soils were treated on site in Hawaii using the SL/2 mobile equipment shown in Exhibit IV

Contaminated Surfaces

Commodore’s SET^TM EPA permit for destruction of PCBs includes ex-situ treatment of contaminated surfaces. Results for treatment of solid surfaces containing PCBs are given in Table II. In most cases, destruction efficiencies exceed 99 %. Solid materials containing various chemical warfare agents have also been treated. These results are given in Table III. In all cases the chemical warfare agents have been effectively remediated to non-detect levels. Treated surfaces include steel, iron, copper, aluminum, wood, cardboard, Lucite, Lexan, PVC, Teflon, fiberglass, concrete, and rubber. The more porous materials such as wood and concrete require crushing or shredding to increase surface areas prior to treatment.

Personnel Protective Equipment

The SoLV^TM process is very effective in decontaminating different types of personnel protective equipment (PPE) such as gloves, boots, cotton, and coveralls. In most cases, the PPE will need shredding or grinding to reduce size and increase surface area. However, after treatment the material occupies less space and can be disposed in a non-hazardous landfill. PPE can be detoxified in Commodore’s S/4 or S-10 treatment system.

Process Streams

Many process streams are amenable to detoxification by SET^TM at the end of pipe before the material is categorized as a waste. In some cases, products of the detoxification can be recycled into the process. Examples include chlorinated hydrocarbons, pesticides, and refrigerants. Such materials are usually treated in the L 1200 treatment system.

Oils

Oils such as contaminated transformer and cutting fluids can be readily detoxified using SET^TM in Commodore’s L-1200 system. This is a liquid unit, which requires the ability to pump the material to be treated. Oils containing over 20,000 ppm of PCB have been detoxified to below 0.5 ppm PCB. Table IV lists data for destruction of PCBs in oils.

PCBs/ Dioxins

One of the more pressing environmental problems is the remediation of PCB contaminated soils or sludges. Commodore has completed numerous treatability studies in house and on site. Only a couple will be discussed herein.

A problem at public utilities is that soil can become contaminated with PCBs near and around transformers. There still are a number of such sites with this problem in the United States. Table V gives data from a clean up of soil from a site in New York State. The soil contained approximately 1200 ppm of PCB (Aroclor 1254) prior to treatment with SET. After treatment the PCB level was reduced to 1.4 ppm. Small quantities of PAHs (pyrene, phenanthrene) were also remediated. The total petroleum hydrocarbons increased, which is what would be expected. As explained above the major organic product of PCB destruction is high molecular weight hydrocarbons. After pH adjustment, the soil can be returned to the site.

Hexachlorobenzene 

SET^TM is very effective in destruction of hexachlorobenzene in soils. Sandy soil containing 67.6 ppm of hexachlorobenzene was treated in the CMDU on site at Las Vegas, Nevada with a SET solution containing approximately 4 % by weight of sodium. The treated sandy soil was found to contain <2 ppm of hexachlorobenzene. GC/MS analysis of the treated soil established that no chlorinated species were detected in the soil.

Bulk Pesticides

Destruction of bulk pesticides has been carried out in Commodore’s Marengo Ohio facility using Malathion. This work was conducted in Commodore’s L1200 liquid unit in 100-pound quantities. Near stoichiometric quantities of sodium were required to destroy the Malathion. The levels of Malathion in the treated material were at non-detect. Most bulk organic pesticides and herbicides containing halogens, phosphorous, or sulfur are amenable to reductive destruction using the SET process. Many waste streams produced when manufacturing pesticides can be remediated using SET^TM..

Pesticides in Soils

In addition to PCBs, other organics in soils, such as pesticides can be remediated. Table VIII gives data from a project where soils from Hawaii and Virginia were contaminated with DDT, DDD, DDE, and dieldrin. In all cases, the soils were remediated to non-detect levels of the respective pesticide. These runs were conducted on site at Port Hueneme, California Naval Station using Commodore’s mobile demonstration unit (CMDU, Figure IV). Soils were shipped in from other naval facilities.

Halogenated Solvents and Chlorofluorocarbon

The phase out of Class I ozone-depleting compounds under the terms of the Montreal Protocol creates serious disposal concerns for organizations which have large quantities of chlorofluorocarbon refrigerants (CFCs) and halons at their facilities. While much of this material is sufficiently pure to be recycled or resold, increasing quantities are appearing which cannot be reused because of their cross-contamination with other compounds. As these materials can no longer be buried on land, discharged into water, or released to the atmosphere, responsible parties are left with destruction as their sole means of ultimate disposal.

By employing know-how gained in part from hazardous waste treatment research, Commodore has developed a patented (Abel, 1996) adaptation of its solvated electron chemistry, which allows treatment of CFC feed-streams and achieves destruction efficiencies equal to or greater than the United Nations target of 99.99% (Table IX).

Polyaromatic hydrocarbons

Solvated electrons readily destroy Polyaromatic hydrocarbons. Studies have been conducted on pure PAHs and on soils containing PAHs. Table X lists data from destruction of pure PAHs. In all cases where PAHs have been detected in soils Commodore has treated, the PAHs have been destroyed to below detection levels. Aromatic materials such a benzene and toluene are destroyed by SET^TM according to the well-known Birch reduction.

Explosives

Commodore has experience detoxifying a number of explosives including TNT, RDX, nitrocellulose, nitroglycerine, tetryl, PETN, Comp B, and M-28. Explosives have been detoxified pure, in conjunction with chemical agent, from actual arms, and in soils. The reaction products were found to contain none of the targeted analytes from EPA method 8330. In addition, the reaction products were found to be non-explosive using standard DOT tests. Reaction products were characterized as polymeric in nature. Similar reactions have been the subject of a master’s thesis ( Mohammed, 1996).

Soil collected form Los Alamos, New Mexico, contaminated with RDX, HMX, and 1,2 DNB, has been remediated using SET. After treatment, no detectable level of explosive was noted. Table XI contains data from this soil.

Chemical Warfare Agents

One of the most exciting applications for solvated electron chemistry is the destruction of chemical warfare agents. A combination of international treaty agreements and U.S. legislation has placed a major responsibility on the U.S. Army to destroy all stockpiled chemical agents over the next decade.

Solvated electron chemistry has been proven to offer a highly efficient, cost-effective solution to the global problem of neutralization and disposal of the highly toxic military and chemical warfare agents currently stockpiled.

Over 300 tests have been conducted by Commodore on all stockpiled agents (GA, GB, GD, GF, Lewisite, VX, HD, HT, T, HN-1, HN-3, HL, picric acid, CG, and CK). Destruction efficiencies of greater than 99.9999 % have consistently been attained. As part of the army ACWA program, reaction products have been extensively characterized. They have also been tested for acute toxicity and found to be CLASS 1 or Class 0 level.

Gravel and Stone

Gravel and stone can be treated in one of two ways. First, it can be washed with high-pressure steam and surfactant. The wash solution is subsequently treated with SET to destroy the contaminant. Gravel and stone can also be crushed to increase the surface area prior to detoxification using the SET^TM process. Once crushed, the material is effectively treated to reduce PCBs and other hazardous organics.

Mixed Wastes

One particularly vexing problem for waste management professionals is mixed wastes (radioactive plus RCRA and/or TSCA waste). Caught between conflicting regulatory jurisdictions and remediation options which frequently prove to be mutually exclusive, mixed waste streams and matrices contaminated with two or more types of contaminant represent a greater level of difficulty and expense to remediate. Illustrative of this problem is soils contaminated with PCBs and with heavy or radioactive metals such as mercury, uranium, or cadmium. Another example, frequently found at nuclear facilities, is soil contaminated with RCRA listed organic compounds and low-level radioactivity.

Because the Commodore soil decontamination process employs solvated solutions at or below room temperature, it has application to mixed waste streams that could not be treated appropriately with thermal processes. In the case of soils containing low-level radioactive components, heavy metals, etc. in conjunction with halogenated organic compounds, the Commodore process can successfully destroy the halogenated organic component without oxidizing or volatilizing the metallic component. Commodore has successfully treated commercial quantities of absorbent contaminated with PCBs and radioactive material using the S/4 at a DOE site in Weldon Spring, Missouri. Table XII lists data for this job. Commodore has also treated a wide variety of low-level radioactive sludges and oils containing RCRA contaminants. Jobs have been conducted on client sites using the mobile SL/2 unit shown in Exhibit IV. Results are given in Table XII and XIIA

In most cases, the radioactive species remains in the matrix for subsequent disposal. Using various wash processes, the radioactive species can be removed form the matrix and volume reduced.

View Table XIIA

Metals Removal

In addition to the destruction of organic contaminants, the SoLV^TM process provides for the effective removal of metals that may contaminate soils or other matrices. This is accomplished by one of several patented post-processes, one being the removal by washing the treated matrix with a mixture of ammonia and water at a high pH using insitu generated sodium hydroxide. This process was demonstrated in the Commodore Mobil Destruction Unit No. 1 (CMDU1) on site at Lockheed/Martin Advanced Environmental Systems (LMAES). Kingwood, TX soil spiked with Aroclor 1260, cobalt (Co), and cesium (Cs) as the contaminants were treated by SET^TM to destroy the PCBs followed by metals removal. The Co and Cs are radionuclide surrogate metals while the other metals are RCRA listed metals. The level of Aroclor 1260 used in the test was 12,000 ppm, and the levels of the metals ranged from approximately 85 to 1800.

The results showed that the PCB destruction/removal efficiencies were typical of previous runs in excess of 99.9%. The metals removal efficiencies are given in Table XIII. The table presents data for two extractions. For the first extraction, metals were removed in the range of 16-93 % depending on the metal of interest. For a second extraction the efficiencies increased to a low of 81 % and a high of 97 % removal. This data is quite impressive in that the majority of the metals were removed with only two extractions.

Competing Reactions

As previously discussed, solvated electrons are very reactive. Apriori, competing reactions may take place, which deplete the electrons so that SET^TM does not completely detoxify the material of interest. Examples of materials that compete for the solvated electron include water, iron, cation exchange with soil matrices and non-hazardous organics present in the matrix being treated. Commodore has conducted many in house process studies aimed at reducing the impact of these competing reactions. Parameters such as temperature, sodium concentration, degree of premix, matrix to sodium ratio, conductivity and pressure are controlled to allow for the most efficient destruction of the hazardous materials, such as PCBs, and least impact of competing reactions. Commodore has engineered complementary processes to reduce these competing chemistries and treated many different contaminated matrices to targeted treatment levels.

In-Situ Treatment

The application of solvated electron chemistry to environmental surfaces and solids in-situ has also been evaluated. In-situ treatment presents two principal challenges: the development of ammonia vapor containment techniques, and penetration of porous substrates. These issues are primarily engineering, rather that chemical, challenges. At this time, engineering designs of an in-situ process have not been completed. Therefore, Commodore does not currently recommend in-situ treatment.

Process Advantages

The above data demonstrates the effectiveness of the SoLV^TM process in destroying hazardous organic materials. The SoLV^TM process is very versatile and adaptable to a broad range of remediation situations.

The process is non-thermal. Most reactions are conducted at 40 degrees F or below. These low temperatures protect against volatile emissions. The destruction process is carried out in a totally closed system. Even the ammonia that is vented when reactors are opened is captured by a scrubber and returned to the reactor during the pH adjustment. During this process, the ammonia is released for reuse. Minor amounts of hydrogen generated from catalytic sodium degeneration are vented through the scrubber system. Volatile hydrocarbons, that may be formed, are condensed and available for fuel use.

The above data demonstrates the effectiveness of the SoLV^TM process in destroying hazardous organic materials. The SoLV^TM process is very versatile and adaptable to a broad range of remediation situations.

The process is non-thermal. Most reactions are conducted at 40 degrees F or below. These low temperatures protect against volatile emissions. The destruction process is carried out in a totally closed system. Even the ammonia that is vented when reactors are opened is captured by a scrubber and returned to the reactor during the pH adjustment. During this process, the ammonia is released for reuse. Minor amounts of hydrogen generated from catalytic sodium degeneration are vented through the scrubber system. Volatile hydrocarbons, that may be formed, are condensed and available for fuel use.

One distinguishing feature of the SoLV^TM process is that no portion of the original molecule is discharged to the atmosphere or to water. The process is reductive in nature and therefore not capable of forming dioxins or furans and similar wastes, which can be found in oxidizing technologies. This is especially beneficial, because communities are becoming increasingly watchful of waste facilities as concerns mount over particulate material that is released to the atmosphere and surrounding water.

The end products from the SoLV^TM process are principally metal salts such as sodium chloride and hydrocarbons. The product streams are not classified as RCRA hazardous and they pass all of the hazard criteria identified in 40 CFR 261.21 through 40 CFR 261.24.

The only raw materials needed for the process are ammonia, sodium, and a neutralizing acid such as sulfuric acid. All of these reactants are commodity chemicals.

When considered in light of other process available, the hardware required implementing the SoLV^TM process is simple and compact. All process equipment is off the shelf and engineered to be mobile. Destruction can take place at the site without the cost associated with transporting hazardous cargo.

- August 31, 2000

Exhibit I 
L1200 Liquid Processing Unit 

Exhibit II 
Solids S/4 Unit

Exhibit III 
Commodore's S-10 Commercial Unit 

Exhibit IV 
Commodore's Mobile SL/2

Abel, A. United States Patent 5,110,364, 1992.

Birch, A. J., 1950, Quart. Rev., (London), 4:69

Birch, A. J., Quart. Rev., (London), 12:17.

Chablay, E., 1914, An. Chem., 9:469-519.

Hudson, F. M., 1963, "A Study of the Reduction of Aromatic Halogenated Compounds by Alkali Metals in Liquid Ammonia," Ph.D. thesis. The University of Tennessee (University Microfilms 64-7860)

Jolly, W. L., 1965, Advan. Chem. Ser., 50:23.

Kennedy, M. V., Stojanovic, B. J., and Shumman, F. L., 1972, J. Environ. Qiality, Vol. 1, No. 1, 63-65.

Mackenzie, K., Kopinke, F.K., and Remmier, M., 1996, Chemosphere, 33:1495.

Mohammed, Mohsin1996, "Solvated Electron Reductions of Aromatic Nitro Compounds and 2-Chloro ethylsulfide in Ethylenediamine at 116^OC," Masters thesis. Mississippi State University.

Vlieger, J. J., Kieboom, P. G., van Bekkum, H., 1986, J.O.C., 51:1389.

Watt, G.W., 1950, Chem. Rev., 46:317.

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