tions, they are efficiently removed by the wet venturi and tower scrubbers in the PAS (see Chapter 1, Figure 1-1). The PAS does not offer any control of NOx, and trial burns to destroy HD/HT in the MPF at TOCDF have demonstrated NOx concentrations on the order of 30 ppm.4

The exposure of activated carbon to mercury is expected to occur exclusively in the PFS units. PFS carbon beds at the disposal facilities are situated downstream of the PAS units for the LIC, MPF, and DFS and will not be exposed to any agent under normal operation. Furthermore, because the PFS carbon beds are situated downstream of the wet scrubbing processes in the PAS, trace concentrations of water-soluble compounds are found in the gas phase; however, no water-insoluble products of agent thermal destruction (e.g., CO2) and contaminant thermal oxidation (e.g., Hg0) would be found.

If an upset were to occur (unlikely) and agent were to pass through the incinerator’s PAS, then both agent and mercury would be present on the carbon. This would pose a problem, because regulations might not allow the carbon to be shipped to a TSDF, and the TSDF might not accept waste containing both agent and mercury. Then, the mercury or the agent would have to be separated from the carbon.


Finding 6-1a. Carbons exposed to agent will not be exposed to mercury in the gas streams handled by the heating, ventilation, and air conditioning system of the munitions demilitarization building. No agent will be present in the gas streams handled by the pollution abatement system filtration system under normal operating conditions.


Finding 6-1b. When mercury-containing mustard agent HD/HT is being destroyed, no agent will be present in the gas streams exiting the pollution abatement system units for the liquid incinerator, deactivation furnace system, and metal parts furnace. However, mercury will be present, so the Army is installing sulfur-impregnated carbon in the pollution abatement system filtration system to capture it.


Recommendation 6-1a. The pollution abatement system filtration system sulfur-impregnated carbon containing mercury should be disposed of separately from other activated carbons used at chemical agent disposal facilities. If generator knowledge confirms that mercury-containing carbon has not been exposed to agent, it should be shipped off-site for disposal in compliance with existing regulations governing mercury-containing solid wastes.


Recommendation 6-1b. In the unlikely event that an operational upset were to cause both mercury and agent to be deposited on the sulfur-impregnated carbon of the pollution abatement system filtration system, the permit might not allow shipping the carbon off-site for disposal, even if sufficient time had elapsed for agent on the carbon to degrade. In this case, fresh carbon should be installed in the pollution abatement system filtration system. The agent- and mercury-contaminated carbon should be processed through the metal parts furnace, thereby destroying the agent and transferring the mercury to the fresh (agent-free) carbon of the pollution abatement system filtration system. This mercury-containing carbon, no longer having agent, could then be shipped off-site for disposal.

REFERENCES

Dsi, H., M. Rood, M. Rostam-Abadi, S. Chen, and R. Chang. 2001. Effects of sulfur impregnation temperature on the properties and mercury adsorption capacities of activated carbon fibers (ACFs). Environmental Science and Technology 35(13): 2785-2791.

Feng, W., E. Borguet, and R.Vidic. 2006. Sulfurization of a carbon surface for vapor phase mercury removal—II: Sulfur forms and mercury uptake. Carbon 44(14): 2998-3004.

Hsi, H., S. Chen, M. Rostam-Abadi, M. Rood, C. Richardson, T. Carey, and R. Chang. 1998. Preparation and evaluation of coal-derived activated carbons for removal of mercury vapor from simulated coal combustion flue gases. Energy & Fuels 12(6): 1061-1070.

Jurng, J., T. Lee, G. Lee, S. Lee, B. Kim, and J. Seier. 2002. Mercury removal from incineration flue gas by organic and inorganic adsorbents. Chemosphere 47(9): 907-913.

Karatz, D., A. Lancia, D. Musmarra, and C. Zucchini. 2000. Study of mercury adsorption and desorption on sulfur impregnated carbon. Experimental Thermal and Fluid Science 21(1-3): 150-155.

Kilgroe, J., and C. Senior. 2003. Fundamental Science and Engineering of Mercury Control in Coal-Fired Power Plants. Arlington, Va.: Air Quality IV Conference.

Liu, W., R. Vidic, and T. Brown. 1998. Optimization of sulfur impregnation protocol for fixed-bed application of activated carbon-based sorbents for gas-phase mercury removal. Environmental Science and Technology 32(4): 531-538.

UDEQ (Utah Department of Environmental Quality). 2008. TOCDF 2003 HD Ton Container Heel Sampling, High Mercury Results. Salt Lake City: Utah Department of Environmental Quality.

Uddin, A., T. Yamada, R. Ochiai, and E. Sasaoka. 2008. Role of SO2 for elemental mercury removal from coal combustion flue gas by activated carbon. Energy & Fuels 22(4): 2284-2289.

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 Information gathered from committee site visit to TOCDF, September 4, 2008.



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