1
Introduction

ACTIVATED CARBON AND CHEMICAL DEMILITARIZATION

For the past two decades, the United States has been destroying its complete stockpile of chemical agents. Nerve agents GB (sarin) and VX, and several forms of mustard agent (a blistering agent) were amassed and stored after World War II, during the Cold War. The U.S. Army’s Chemical Materials Agency (CMA) is responsible for managing the program for the destruction and disposal of these agents and the munitions and containers in which they are stored. This program represents a major initiative through which the United States recognizes and complies with the international treaty known as the Chemical Weapons Convention (CWC), to which it is a signatory.

At the facilities where chemical agents are being destroyed, effluent gas streams pass through large activated carbon filters before venting to ensure that any residual trace vapors of agents and other pollutants do not escape into the atmosphere in exceedance of regulatory limits.1 Most of these adsorber units have never been exposed to agent. Significantly in this regard, the system design and operational procedures are designed to limit agent exposure to the carbon in Banks 1 and 2 of the multibank adsorber units filtering the plant heating, ventilation, and air conditioning (HVAC) air.2 The degree of agent contamination for carbon filters associated with process units (e.g., furnaces) varies from those having had no exposure to agent to those that are highly contaminated, such as the filter units on the vent lines of the agent collection system storage tanks in the facilities. The large amount of carbon (both exposed and unexposed) being stored at each of the sites awaits proper disposal in a safe manner in compliance with all applicable laws and regulations. All the carbon will have to be disposed of as a requirement for final closure of these facilities to take place. The applicable regulations are primarily related to satisfying requirements mandated by the federal Resource Conservation and Recovery Act (RCRA), and in some cases, more stringent requirements have been added by each state.

The National Research Council (NRC) Board on Army Science and Technology has provided advice and guidance to the Army’s program for chemical stockpile destruction since its inception more than two decades ago and is very familiar with the technical, safety, health, and operational aspects of processes used for destroying chemical agents and munitions. Thus, in March 2008, the CMA requested the NRC to convene a committee to study, evaluate, and recommend the best methods for proper and safe disposal of the used carbon that continues to be accumulating at the operational disposal facilities.

1

Note that what are termed “carbon filters” in Army parlance are more accurately described as “carbon adsorption beds.”

2

The plant ventilation air moves through a cascade system starting with areas of the plant that are uncontaminated through areas that are progressively more contaminated with agent before entering the carbon filter units. Typically there are six sequential banks of carbon filters in the filter units that filter the munitions demilitarization building (MDB) HVAC air.



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1 Introduction ACTIVATED CARBON AND CHEMICAL degree of agent contamination for carbon filters asso- DEMILITARIZATION ciated with process units (e.g., furnaces) varies from those having had no exposure to agent to those that are For the past two decades, the United States has been highly contaminated, such as the filter units on the vent destroying its complete stockpile of chemical agents. lines of the agent collection system storage tanks in the Nerve agents GB (sarin) and �X, and several forms of facilities. The large amount of carbon (both exposed mustard agent (a blistering agent) were amassed and and unexposed) being stored at each of the sites awaits stored after World War II, during the Cold War. The proper disposal in a safe manner in compliance with U.S. Army’s Chemical Materials Agency (CMA) is all applicable laws and regulations. All the carbon will responsible for managing the program for the destruc- have to be disposed of as a requirement for final closure tion and disposal of these agents and the munitions of these facilities to take place. The applicable regula- and containers in which they are stored. This program tions are primarily related to satisfying requirements represents a major initiative through which the United mandated by the federal Resource Conservation and States recognizes and complies with the international Recovery Act (RCRA), and in some cases, more strin- treaty known as the Chemical Weapons Convention gent requirements have been added by each state. (CWC), to which it is a signatory. The National Research Council (NRC) Board on At the facilities where chemical agents are being Army Science and Technology has provided advice and destroyed, effluent gas streams pass through large acti- guidance to the Army’s program for chemical stockpile vated carbon filters before venting to ensure that any destruction since its inception more than two decades residual trace vapors of agents and other pollutants do ago and is very familiar with the technical, safety, not escape into the atmosphere in exceedance of regu- health, and operational aspects of processes used for latory limits.1 Most of these adsorber units have never destroying chemical agents and munitions. Thus, in been exposed to agent. Significantly in this regard, the March 2008, the CMA requested the NRC to convene system design and operational procedures are designed a committee to study, evaluate, and recommend the best to limit agent exposure to the carbon in Banks 1 and 2 methods for proper and safe disposal of the used carbon of the multibank adsorber units filtering the plant heat- that continues to be accumulating at the operational ing, ventilation, and air conditioning (��AC) air.2 The disposal facilities. 1Note that what are termed “carbon filters” in Army parlance are that are progressively more contaminated with agent before entering more accurately described as “carbon adsorption beds.” the carbon filter units. Typically there are six sequential banks of 2The plant ventilation air moves through a cascade system start - carbon filters in the filter units that filter the munitions demilitariza - ing with areas of the plant that are uncontaminated through areas tion building (MDB) ��AC air. 

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 INTRODUCTION CHEMICAL STOCkPILE DISPOSAL PROGRAM of sulfur-impregnated activated carbon, which will adsorb mercury from the stack gases before they are released to the atmosphere. Three other sites that use Overview incineration are now also in operation: the Umatilla The United States manufactured and stockpiled Chemical Agent Disposal Facility (UMCDF) in Uma- about 31,000 tons of two nerve agents, GB and �X, and tilla, Oregon, the Anniston Chemical Agent Disposal one blister agent, sulfur mustard agent. The mustard Facility (ANCDF) in Anniston, Alabama, and the Pine agent is in three forms: � mustard is an impure form of Bluff Chemical Agent Disposal Facility (PBCDF) in mustard agent containing other products produced dur- Pine Bluff, Arkansas. ing the chemical synthesis; �D is the distilled product Public Law 102-484 of 1993 mandated destruction of �, nominally pure mustard agent; and �T is a mix- of the entire chemical weapons stockpile and required ture of � with T, a related compound, which provides a the Secretary of the Army to evaluate potential alter- eutectic that lowers its freezing point below cold winter natives to the Army’s baseline disassembly and incin- temperatures because pure mustard agent freezes at eration process, considering whether—initially for a 14.5°C. These chemical agents and munitions were low-volume site—the application of such alternatives stored at nine sites, eight of them in the continental could complete demilitarization operations by Decem- United States and one at Johnston Atoll in the Pacific, ber 31, 2004, the deadline set at that time, in a sig- about 700 miles southwest of �awaii. nificantly safer manner than the baseline disassembly In 1985, Congress mandated that the Army establish and incineration process and at least as cost-effective. a program to destroy at least 90 percent of the nation’s This congressional directive led to the use of chemical unitary chemical stockpile (Public Law 99-145) with neutralization (hydrolysis) at two sites where only bulk particular emphasis on M55 rockets. The U.S. Army agent in ton containers was stored. Caustic NaO� solu- selected incineration as the most effective method of tion at 194°F was the neutralization reagent used at the destroying the chemical munitions in the stockpile. Newport Chemical Agent Disposal Facility (NECDF) Incineration is very “democratic,” i.e., it oxidizes in Newport, Indiana, where �X had been manufactured chemical compounds to stable chemical forms such and stored. �ot water at 194°F was the neutralization as water and carbon dioxide and inorganic salts of reagent used at the Aberdeen Chemical Agent Dis- sulfur, phosphorus, and fluorine. The first site where posal Facility (ABCDF) at Aberdeen Proving Ground, an integrated prototype facility was built, namely, Maryland, where �D in ton containers had been stored. the Johnston Atoll Chemical Agent Disposal System, N ECDF and ABCDF have completed destruction completed disposal operations in 2001. The plant has operations and ABCDF has completed closure. since been demolished and following closure of the site Congress then mandated (Public Laws 104-201 and in 2003, the part of Johnston Atoll where the facility 104-208) that the facilities at the two remaining sites, was located, Johnston Island, is now abandoned and is the Pueblo Chemical Agent Destruction Pilot Plant being allowed to return to its original natural condition. (PCAPP) in Colorado and the Blue Grass Chemical In August 1996, the Tooele Chemical Agent Disposal Agent Destruction Pilot Plant (BGCAPP) in Ken - Facility (TOCDF) at the Deseret Chemical Depot in tucky, use a method other than incineration to destroy Tooele, Utah, which originally stored about 45 percent c hemical agent. The Army has selected chemical of the total stockpile, was the first continental U.S. site neutralization, followed at PCAPP by bioremedia- to begin destruction operations. It has completed the tion and at BGCAPP by supercritical water oxidation. destruction of all the GB and �X munitions stored at Construction of these two plants was under way at the the Deseret Chemical Depot, including all of the M55 time this report was being prepared. At all operating rockets, which are considered to have the highest risk, sites, activated carbon continues to be used to filter the and is presently destroying the remaining mustard ventilation air and process gas streams prior to their agent stockpile. In the course of the mustard agent release into the atmosphere and to protect personnel destruction campaign, analysis has revealed that some from accidental releases. of the mustard agent ton containers contain varying In 1997, the U.S. Congress ratified the CWC, an amounts of mercury, a RCRA-controlled substance. international treaty banning the use and stockpiling of This unexpected development has led to modifications chemical weapons. The CWC required that all signa- in the plant and process designs, including the use tory nations destroy their entire stockpiles within 10

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0 DISPOSAL OF ACTIVATED CARBON FROM CHEMICAL AGENT DISPOSAL FACILITIES years of signing the treaty, making the deadline April because the chemical processes must be specific to the 29, 2007. �owever, later, both the United States and particular agent being treated. Russia applied for onetime 5-year extensions to this Whether incineration or neutralization technology deadline, which were granted. Still, the United States is the primary method for agent destruction, a generic is not expected to meet this date, because PCAPP and series of steps are taken to dispose of the stockpile. BGCAPP have not yet begun disposal operations. Munitions are moved from stockpile storage areas to the munitions demilitarization building (MDB) in on-site containers (ONCs) or enhanced on-site con- Brief Description of the Chemical Agent tainers (EONCs), which are designed for retention Destruction Process and monitoring of any agent leakage that might occur The following provides a generic description of the during transport. The ONCs or EONCs are received at process facilities used to dispose of the Army’s chemi- a container handling building connected to the MDB cal agent stockpile. It includes a summary of the uses and are then moved to an unpack area, where the muni- of activated carbon in those processes and the facilities tions and bulk items are removed and put on input used to house and control the processes. More detailed conveyors to the MDB. Different conveyor systems descriptions will be presented in Chapter 2. transfer different types of munitions and agent contain- Figure 1-1 is a schematic drawing that generi - ers from the unpack area to the explosives containment cally depicts the process that takes place in a typical room(s) of the MDB, where the energetic materials are chemical agent disposal facility using incineration removed from the particular type of munition being technology. Differences in configuration exist because processed—projectile, mortar, mine, or bomb. For ton each site stores and destroys different types of agents containers and airplane spray tanks, there are no ener- and munitions, and also because the more recently getics to be removed. constructed facilities have taken advantage of lessons The removed energetic components are then pro- learned during operations at the older sites. Facilities cessed separately from the agent, which is subsequently using chemical neutralization also have differences drained or washed from munitions. When processing M55 rockets, the agent is drained before the rocket FIGURE 1-1 Schematic of the baseline incineration system. SOURCE: Personal communication between Timothy Garrett, Site Project Manager, ANCDF, and Margaret Novack, NRC study director, February 9, 2009. FIGURE 1-1.eps

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 INTRODUCTION (including the propellant in its motor) is sheared into abatement system (PAS) that includes wet scrubbers segments. The rooms in which these operations are and a PAS filtration system (PFS) containing activated conducted become contaminated with agent vapors carbon in horizontal beds. The PAS at TOCDF formerly and liquid. Any personnel entering these rooms must consisted only of wet scrubbers, but a PFS using sulfur- be sealed in a demilitarization protective ensemble suit impregnated carbon was being added to each PAS at the that includes a supply of breathing air under positive time this report was being prepared. The carbon filters pressure. at the other sites using incineration technology serve Energetics are either burned or chemically destroyed the same function as the MDB ��AC filters, although by neutralization. The agent drained from munitions trial burns have validated that the incineration products flows into agent collection tanks, which in turn feed a are releasable to the atmosphere without the PFSs. The liquid agent incinerator where the agent is burned or, latter were added at ANCDF, UMCDF, and PBCDF in for plants using neutralization, reacted with a sodium response to concerns expressed by the residents of the hydroxide solution or hot water and subsequently adjacent communities. These PFS filters have never processed further to convert reaction products to envi- been exposed to chemical agent. ronmentally acceptable materials. Drained munitions, In facilities using neutralization, vapor spaces in which in some cases may contain a solidified heel of process vessels are discharged to an off-gas treatment agent, are processed in a metal parts furnace (MPF) system (OTS) whose stage is an activated carbon filter. at incineration sites or in an electrically heated metal A gas leaving the OTS then flows into the MDB ��AC parts treater (MPT) at the other sites. These munition system at the facility and passes through the ��AC casings are heated to at least 1000°F for no less than 15 carbon filters. minutes, which has become an established performance At every site, all process control rooms and occupied standard for achieving complete agent decontamination clean areas and laboratories have carbon filters on out- since the beginning of the chemical stockpile disposal side air flowing into these rooms to protect the work- program. ers inside. These filters preclude agent contamination of these areas in the event of a release of agent from munitions outside the MDB. In addition, each person Use of Carbon Filtration Systems at Chemical Agent working on-site is equipped with a protective mask Disposal Facilities containing an M-40 carbon cartridge. All these uses of All of the preceding processing steps, from receipt carbon, other than the protective masks, are depicted of the ONCs or EONCs to destruction of agent and schematically in Figure 1-2. energetics, are housed in the MDB, which has a cas- In summation, carbon filters are used extensively at cading ��AC system designed to move ventilation air all of the Army’s chemical agent disposal facilities to from clean, uncontaminated areas to areas of increasing protect workers and the public from the remote pos- agent contamination in the MDB. The ��AC system sibility that chemical agent in air or gas streams might then discharges the air through banks of activated be released to the environment. Only two of the types carbon filters. In each unit, there are typically six of filter units (which will be discussed in Chapter 2) separate filter banks arranged in series for removing are exposed to agent under normal operating condi- airborne contaminants in ventilation air from process tions, those that filter the ��AC air from the MDB areas. Each bank contains approximately 2,200 lb of and the filters installed on the agent collection system carbon. vessels. The other filters (such as the PFS) would only In facilities using incineration processes, except be exposed to agent in the event of a serious upset. TOCDF, exhaust gases from each furnace and after- Each site will have nominally 500,000 lb of carbon burner system go to a high-performance pollution to be disposed of after all of the chemical agents and munitions stored there have been destroyed. 3As noted previously, what the Army calls “carbon filters” are STATEMENT OF TASk technically various configurations of carbon adsorption beds. No filtration processes are involved. �owever, for consistency with the As noted previously, the Army requested the NRC language typically used for discussing U.S. chemical demilitariza- to assemble a committee to examine the characteristics tion, the terms carbon filters and carbon filtration have been used of the spent carbon and alternatives for its disposal. in this report.

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 DISPOSAL OF ACTIVATED CARBON FROM CHEMICAL AGENT DISPOSAL FACILITIES Munitions Used Carbon from Stockpile Control Room Ambient Air Filter Munitions Demilitarization Unpack Area Building Munitions V Ventilatio n Disassembly e Air Operations n t i l Energetics Metal Agent a + Metal Used HVAC Parts t Parts Carbon Filter i Agent Farm o ACS Collection n Filter Metal Parts Deactivation Tank Furnace Furnace D u Scrap c Liquid Metal t Incineration i Chamber n g Used Carbon Pollution Abatement Systems Used PAS Filtration Carbon Filters Stack Laboratory, Site Maintenance Facility, Mechanical Inlet Air Exhaust Air Maintenance Facility, Carbon Filter Carbon Filter Electrical Maintenance Facility. and Personnel and Maintenance Building Used Carbon FIGURE 1-2.eps FIGURE 1-2 Sources of used carbon in a typical chemical agent disposal facility.

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 INTRODUCTION The full statement of task together with the preamble environmental regulations. This would allow them to is as follows: make recommendations on the proper disposal of the used carbon from chemical agent disposal facilities. The U.S. Army’s Chemical Materials Agency has been Several members of the committee also had a perspec- engaged for nearly two decades in a program to destroy the tive on the public interest aspects of the destruction of nation’s stockpile of obsolete chemical agents and munitions. At first, in the early 1990s, these efforts were limited to a chemical munitions, notwithstanding that the scope of single first-generation facility located on Johnston Island this report was limited to a technical and regulatory southwest of the �awaiian Islands, where approximately examination of alternatives for waste carbon. 4 percent of the original stockpile of over 31,000 tons of agents was stored. In August 1996, agent disposal operations began at the first disposal facility in the continental United STUDY SCOPE States at Deseret Chemical Depot in Tooele, Utah, where some 44 percent of the total stockpile tonnage was located. The first bullet in the statement of task directs the Since then, disposal operations have taken place at other committee to assess the current plans and path forward facilities at five additional storage sites in the continental for the agent-contaminated activated carbon gener- United States. Four of these sites use incineration technology ated in the ��AC system at the sites. �owever, after and two have used or are using hydrolysis (neutralization) conferring with the sponsor, the committee interpreted technology. At present, over 50 percent of the original stock - pile tonnage has been destroyed. the second bullet to include the proper disposal of all carbon at the sites whether or not the carbon had As program operations have progressed, so has the accumu- been exposed to agent. Accordingly, the committee lation of large quantities of agent-contaminated activated carbon resulting from agent processing. This material is has restricted its assessment to the technological and projected to be one of the largest secondary waste streams to permitting aspects of the carbon management and dis- remain in storage at the end of munitions destruction opera- position at chemical agent disposal facilities under the tions. Consequently, disposal of the ��AC carbon, which authority of the CMA. The committee has given some may require some pre-treatment prior to final disposition, consideration to the liability that may factor into a site’s could have a significant impact on closure costs and schedule selection of certain alternatives over others that are also for the Army’s chemical agent destruction facilities. technically acceptable. The cost of the alternatives was The National Research Council will establish an ad hoc not studied. committee to: Importantly, the committee has used the following • examine the current heating, ventilation, and air condition- terminology throughout the report. If the carbon has not ing (��AC) systems of the U.S. Army's Chemical Materi- been exposed to agent, it is called “unexposed carbon.” als Agency (CMA) that use activated carbon and consider Any carbon that has been exposed to agent is called the overall quantity and characteristics of the CMA ��AC secondary wastes “exposed carbon.” As discussed in Chapter 4, because • assess the current plans and path forward for contaminated the chemical agent degrades and forms hydrolysis prod- carbon management and disposition at Army chemical ucts with the adsorbed moisture, exposed carbon may agent disposal facilities or may not contain agent. “Used carbon” or “carbon” • evaluate commercial and established industry alternatives refers to both exposed and unexposed carbon. Mustard for contaminated carbon disposal, i.e. best practices, processes and equipment suitable for use by the Army agent exists in three forms: �, �D, and �T. The report (considering both on-site and off-site usage), including may refer to �D when all three forms were intended. characterization and pre-treatment requirements Although all the chemical agent disposal facilities • in the foregoing context, assess the scientific support need- that use incineration are modeled after TOCDF, there ed for obtaining regulatory approvals at CMA facilities. are minor variations in the design and procedures from site to site. The descriptions given in this report focus In response to this request, the NRC Board on Army on the ANCDF design and procedures. Where the Science and Technology assembled the Committee to committee was made aware of any variations, they are Examine the Disposal of Activated Carbon from the mentioned in footnotes. �eating, �entilation, and Air Conditioning Systems at Chemical Agent Disposal Facilities (CMA Carbon Committee). This committee was made up of indi - ORGANIZATION OF THIS REPORT viduals with expertise in the chemical demilitarization In Chapter 1 the committee has provided a brief program, the chemistry of chemical agents on carbon, background and overview of the chemical stockpile the surface chemistry of carbon, risk assessment, and

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 DISPOSAL OF ACTIVATED CARBON FROM CHEMICAL AGENT DISPOSAL FACILITIES disposal program, a short description of the facility summarizes commercial and industrial practices for designs, and a summary of the usage of carbon filtration management of carbon being used in industrial settings. at the sites. Also presented were the statement of task In Chapter 6, the committee addresses the issues unique for the study and the scope of the study which the com- to the disposal of activated carbon that has become mittee has adopted. In the next paragraph the committee contaminated with mercury, which is expected at some turns to the organization of the rest of the report. sites where mustard agent contaminated with mercury Chapter 2 gives details of the use and on-site man- must be destroyed. Finally, Chapter 7 discusses and agement of activated carbon at the facilities. Chapter 3 assesses the Army’s past experience with the disposal discusses the regulatory issues that impact the usage of used carbon and the disposition options available and disposal of carbon. Chapter 4 describes adsorption for used carbon from chemical agent disposal facility fundamentals and discusses the chemistry and fate of operations. It also provides the committee’s general the agents on activated carbon as well as analytical findings and recommendations. methods to measure their concentrations. Chapter 5