Lewisite waste disposal

The U.S. Army does not plan to incinerate the lewisite stored in 10 one-ton containers at the Tooele site. The method of destruction to be employed has not been finalized, but the leading candidate is treatment with sodium permanganate to precipitate a manganese oxide-arsenic solid (Ember, 2006). This solid would be encased in concrete and disposed of in a permitted hazardous waste landfill, with the remaining liquids treated further and injected into a deep well. 

The contractor, Western Research Partnerships, Calgary, AB (Chem-Security Ltd. and Western Research Ltd. Both companies are now a part of BOVAR Inc., Calgary) supplied and operated a transportable incinerator which was used to thermally treat the scrap waste and emptied, decontaminated ordnance items and to bum mustard. Lewisite was chemically destroyed by peroxide oxidation in a transportable facility and the arsenic salt by-products were stabilized in concrete for on-site disposal in a marked landfill. 

As discussed in NRC 1999a, this conclusion is based on the fact that CAIS sets contain no explosives and relatively small quantities of agent, and that the hazards of the chemical agents in CAIS (mustard and lewisite) fall within the range of the hazards presented by industrial chemicals ordinarily disposed of according to U.S. hazardous waste regulations. 

Arsenic found in lewisite is converted in the red and charcoal-L processes into chlorovinylarsonic acid (CVA) in quantities of up to 3 percent by weight in the neutralent waste stream (Table 2-2). The fate of CVA depends on the posttreatment processes. In a SCWO reactor and in the GPCR caustic scrubber brine, the CVA is expected to be converted to sodium arsenate salts (e.g., Na3As04 and Na4As207), which can then be treated with ferric chloride to produce ferric arsenic salts for disposal in a hazardous waste landfill. This treatment scheme, which was developed in Canada, is... 

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