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REQUIREMENTS AND CONSIDERATIONS FOR CHEMICAL DEMILITARIZATION TECHNOLOGIES 78 system is then used to simultaneously destroy residual agent, explosives, propellants and decontaminated residual weapons parts. Subsequently, a heated discharge conveyer ensures the time and temperature requirements for thermal decontamination of the rocket pieces by carrying burned materials on an electrically heated conveyor for at least 15 minutes. In addition to the above main component streams, additional solid wastes of the disposal process include wooden shipping and storage pallets, the protective clothing used by personnel, cleanup equipment, and other items potentially contaminated by chemical agent. These wastes are called dunnage and are combined for disposal with any compatible solid wastes from other processes in the system. The requirement to treat this waste stream is optional; experience at the baseline facility has shown that the contamination of these wastes is low and they can be chemically cleaned (e.g., with decontamination fluids) to a level that allows their transport and disposal in a hazardous waste landfill. Any alternative process that fails to destroy the chemical agent completely or that creates new wastes that cannot be discharged to the environment may create additional process stream requirements. An example of such new wastes might be the scrubbing solution used in decontaminating equipment (and related salts, if the solution is reduced to a solid waste stream); in the baseline technology, these wastes are fed to the liquid incinerator. Finally, all work spaces are normally ventilated with the air flow proceeding in the direction of increased probability of contamination, from the control room and analytical laboratories through the work areas. Each succeeding area is maintained at slightly lower pressure to ensure that this positive flow, and thus any leakage, occurs in the proper direction. In all, therefore, six main process streams must be treated: (1) bulk liquid agent; (2) solids contaminated with agent without explosives or propellants; (3) solids with explosives or propellants contaminated with agent; (4) solid dunnage, such as packing materials and used protective suits; (5) decontamination fluids; and (6) ventilation air. PROCESSING RATES The rate at which weapons and their resultant process streams must be destroyed is set by several factors. First, all weapons and agent at each site must be demilitarized by a target completion date. As noted in Chapter 1, this
REQUIREMENTS AND CONSIDERATIONS FOR CHEMICAL DEMILITARIZATION TECHNOLOGIES 79 FIGURE 4-1 JACADS demilitarization process. Source: PEIS (1988).
REQUIREMENTS AND CONSIDERATIONS FOR CHEMICAL DEMILITARIZATION TECHNOLOGIES 80 date was initially set by U.S. legislation and has been extended several times. To comply with international treaty, it was recently reset to December 31, 2004. Second, only part of the time from now through 2004 is available for operations. There are many other necessary steps: technology selection; environmental reviews; congressional authorization; possible research, development, and demonstration of any alternative technology; design, permitting, construction; and testing of facilities. In addition, these times could be prolonged if multiple-step destruction processes required the transport of partially decontaminated materials to one or more centralized full-decontamination facilities. One option discussed by the committee (see Chapters 1 and 8) might relieve the time pressure at some sites while allowing agent to be detoxified and weapons disassembled to meet treaty requirements. Final oxidation of all organic residues, destruction of energetics, and decontamination of metals could be deferred by local storage or transport of partially treated materials to other sites. The processing rate for agents and munitions will probably be set by the mechanical operations in the reverse assembly process. This process will set both a maximum rate, due to mechanical limitations, unless the reverse assembly process is increased by multiple lines, and a minimum rate for performing these operations with a reasonable degree of efficiency. Significant delays between reverse assembly and later decontamination and destruction steps would add to internal inventory storage requirements as well as increase the probability of accidents. The current program was designed so that the first disposal facilities would be constructed at sites with the largest chemical weapon storage inventories. The baseline technology would then be used at the sites with smaller inventories, resulting in shorter total operating periods. Processing rates for the largest continental site inventory at Tooele Army Depot (TEAD) are set to destroy the inventory in 4 to 5 years, with a specified flow rate of 1050 pounds of liquid agent per hour. This rate is about 50 percent greater than the collection rate from the simultaneous operation of two identical M55 reverse assembly lines, each having a nominal capacity of 35 rockets per hour (U.S. Army Corps of Engineers, 1987).1 The 155-mm projectile processing rate, at 500 projectiles per day, is only 130 pounds of agent per hour. For the smaller stockpile sites, a nominal capacity of 100 pounds per hour of agent destruction is assumed in subsequent discussion of waste gas storage technologies. 1 If two reverse assembly lines are used, each at a rate of 35 M55 rockets per hour, with 10.5 pounds of agent per rocket, the accumulation rate of drained agent will be 735 pounds per hour.
