Review and Evaluation of Alternative Chemical Disposal Technologies (1996) / Chapter Skim
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7 NEUTRALIZATION TECHNOLOGY FOR MUSTARD AGENT HD
7 NEUTRALIZATION TECHNOLOGY FOR MUSTARD AGENT HD
Pages 120-142
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From page 120... ...
Intensive testing in the past two years has led to selection of direct hydrolysis with hot water followed by biodegradation of the hydrolysis product as the best candidate for scale-up to a pilot plant demonstration (U.S.
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From page 121... ...
Configuration 1 (Figure 7-1) is neutralization followed by biodegradation with on-site water recycling and photochemical VOCs 1 Water I; Ultraviolet/Peroxide · Filtration Evaporation Biodegradation Activated Sludge Process Ton Container 3X Decontamination Or Waste Biosolids Off-Site Ton Containers · 5X Decontamination and Smelting Solidification :_ Waste Salts FIGURE 7-1 Process Configuration 1: Neutralization followed by on-site biodegradation, including water recycling and photochemical oxidation of VOCs.
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From page 122... ...
is neutralization followed by biodegradation, with process effluents discharged to a FOTW. Photochemical oxidation is used to destroy VOCs to FOTW standards, but water recycling is not used.
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From page 123... ...
during neutralization or adding sodium hydroxide to the hot water prior to introduction
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From page 124... ...
or passed through 3The current detection limit for HD in Hydrolysate is 10 ppb. Destruction of HD to less than 200 ppb represents a destruction efficiency of greater than 99.9995 percent; destruction to less than 10 ppb a photochemical oxidation unit in which hydrogen peroxide is added and the solution is irradiated with ultraviolet light to destroy the organic compounds (configurations 1 and 2~.
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From page 125... ...
The vapors from the ton container cleanout process, neutralization reactors, and hydrolysate holding tanks are all passed through a single caustic scrubber. Then they are reheated to reduce the relative humidity of the gas; filtered through activated-carbon beds, which serve as guard beds to ensure there is no release of toxic organic vapors; filtered through the plant-ventilation activated-carbon filter beds; and finally discharged to the atmosphere.
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From page 126... ...
Under these conditions, the VOCs are both directly degraded by photolytic dissociation and oxidized by HO radicals, which are formed by the photochemical dissociation of hydrogen peroxide (Solarchem Environmental Systems, 19964. The products of the photochemical oxidation are simple organic compounds (aliphatic organic acids such as acetic acid)
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From page 127... ...
Processing at bench scale also has demonstrated the successful destruction of HD present in the heel removed from a ton container.6 Thus, the neutralization process has been demonstrated to work well for the distilled HD stored at the Aberdeen site. Overall, 161 kg of HD were destroyed in the laboratory and bench scale studies at Aberdeen (Novad, 1996~.
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From page 128... ...
. The primary objectives of the laboratory testing were to determine treatment efficiency, the quality of effluent from the process, the optimum operating conditions, and the effects of HD impurities (e.g., ton container heel and iron floc)
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From page 129... ...
In configurations 1 and 2, the TPC proposes to use a combination of ultraviolet light and hydrogen peroxide to destroy VOCs that would be subject to regulatory constraints if they were released to water or a landfill (land-ban chemicals)
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From page 130... ...
The use of hot water for the ton container clean-out process should result directly in the destruction of a large fraction of the residual HD via the same hydrolysis reaction that occurs in the neutralization operation for the drained HD. Hydrolysis in the caustic scrubber should destroy any residual HD present in the process gases prior to filtering through activated carbon.
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From page 131... ...
In addition, the operating conditions for treatment of ton container cleanout and decontamination solutions, either separately or with agent, have not been defined, although similar materials from laboratory and benchscale testing have been handled without difficulty. The sodium content of the spent caustic solution used to decontaminate the work areas is not expected to be an issue for either the neutralization or biotreatment processes.
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From page 132... ...
Scale-up of the results has been extrapolated to a set of nine ultraviolet reactors and appropriate hydrogen peroxide feed systems (Solarchem Environmental Systems, 1996~. Biological Treatment of Hydrolysate Biodegradation of the organic constituents of the hydrolysate (primarily thiodiglycol)
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From page 133... ...
(Kosson et al., 1995~. Agent Detoxification and Consistency of Standards Laboratory and bench-scale tests have shown that the primary neutralization process can destroy the chemical loan order-of-magnitude estimate of the partial pressure of sulfur mustard above an aqueous solution can be made based on pure-component vapor pressure and aqueous solubility (Mackay and Shui, 19811.
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From page 134... ...
ton containers. Configuration 1 produces 9 kg of solid waste per kg of agent destroyed.
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From page 135... ...
hydrolysate, water, `/ ~Dilution required to air, sodium carbonate, biodegrade thiodiglycol nutrients in hydrolysate Biomass digester and filter press Water recycle evaporator Photochemical oxidation Residual salt solidification/ stabilization biomass from SBRs, air, conditioning chemicals effluent water from `/ biodegradation sodium hydroxide, i/ ./ hydrogen peroxide concentrated salts from water recycle Requires dilution water for config. 2 Number of unit operations 9 7 6 3 `/ = required unit operation.
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From page 136... ...
Biodegradation aqueous effluent Solid Wastes Ton containers, valves, plugs, and metal cuttings Solidified salts Biomass filter cake Activated carbon scrub and filter through carbon before atmospheric discharge 1,651 1,651 1,651 1,651 filter through 71,339 71,339 71,339 n.a. carbon before atmospheric discharge to TSDF (biodegradation)
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From page 137... ...
Thus, for thawing ton containers in cold weather, procedures must be developed that are consistent with the limitations on the total agent inventory in the processing facility (currently established as the {.9-m3 limit for the agent storage tank)
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From page 138... ...
Water recycling, if incorporated in the overall process, may require ferric chloride as a flocculating agent and polymeric water conditioners. If the photochemical oxidation process is used to destroy VOCs, hydrogen peroxide must be supplied.
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From page 139... ...
The sand filter and evaporator are common operational equipment, usually very reliable and robust. The photochemical oxidation system uses lamps and peroxide injection systems that are proven and reliable.
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From page 140... ...
In addition, the ton containers require heating to melt frozen HD in the winter. Although ton-container heaters will be provided, the cold containers may require extra heating for the container storage area.
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From page 141... ...
As with the other technologies, process-safety risk factors for the neutralization process can be divided into factors inherent in handling agent prior to its introduc tion to the neutralization process and factors related to the neutralization technology itself. The risk factors inherent in handling agent prior to neutralization are the same as the risks for the other technologies; they include storage risk, transportation risk, and risks associated with punching, draining, and cleaning ton containers.
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From page 142... ...
. There would be three two-reactor trains, one of which would be used initially as a pilot facility to demonstrate the effectiveness of the neutralization and biodegradation processes.
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