Two alternatives to incineration can break down the active agents of chemical weapons, but rendering the breakdown products harmless will be more difficult, says a report from the US National Research Council issued on Tuesday.
The Chemical Weapons Convention Treaty requires the US to destroy its stockpile of chemical weapons by April 29, 2007. The Army selected incineration, which is complete at one site and 70 percent finished at another. Incinerators are complete or being built for munitions at three other sites, while bulk chemicals in one-tonne containers at two other sites will be chemically neutralised.
However, opponents worried about incinerator emissions convinced Congress to force the Pentagon to consider two alternatives for munitions at two sites, in Pueblo, Colorado, and Lexington, Kentucky.
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The Pentagon tested two approaches that break down the complex chemical weapon compounds in two stages. First water or a base breaks chemical bonds, splitting the molecules into smaller and less toxic molecules. Then either microbes immobilised in a 鈥渂ioreactor鈥� or processing with superheated, high pressure water converts the fragments into innocuous materials.
The hydrolysis used in first step 鈥渆ffectively destroys the chemical agent and the explosives in the munitions鈥�, says study team chairman Robert Beaudet, a chemist at the University of California at Los Angeles.
Mustard gas
However, the panel sees potential problems with both second-step processes. Beaudet says the problems 鈥渁re certainly surmountable for both technologies, although the hurdles appear to be much more serious and more numerous for supercritical water oxidation鈥�.
The panel鈥檚 report notes that both technologies 鈥渉ave never been operated as total integrated processes,鈥� so further debugging may be needed.
The research council also released a separate report evaluating a modified incineration process developed for Pueblo. That stockpile contains only mustard-gas weapons, allowing use of a single incinerator for both the chemical agents and the shells containing them, instead of separate ones used elsewhere.
鈥淭he heart of this is not new technology,鈥� says panel chairman Peter Lederman, a chemical engineer at the New Jersey Institute of Technology in Newark. The simpler single-incinerator system should be safer and operate faster, 鈥渂ut we haven鈥檛 proved that,鈥� he told 快猫短视频.
The process involves freezing the chemical agent, and Army engineers have yet to demonstrate how well the frozen material burns.