138th Year... and still on the job!	Sunday February 18, 2007

Group details chemical weapon destruction process

By JOHN NORTON
THE PUEBLO CHIEFTAIN

A local panel got a briefing Wednesday afternoon on how wastewater from the destruction of mustard agent would be broken down by microbes, if the process is done here.

The Design Options Working Group, a subcommittee of the Colorado Chemical Demilitarization Citizens Advisory Committee, heard a report from Jim Earley of Science Applications International Group, the Bechtel subcontractor developing the process.

The Assembled Chemical Weapons Alternatives program, the Defense Department agency overseeing weapons destruction at the Pueblo Chemical Depot and the Blue Grass Army Depot, has not decided on how it will treat the wastewater, called hydrolysate, but Bechtel is continuing to work on an on-site option just in case the work eventually is done here.

The CAC has recommended on-site treatment and its opinion has been endorsed by two studies that warn off-site shipments could result in delays and costly litigation by other communities, eating up the $150 million savings the Defense Department says it could earn by not building a treatment plant here.

On-site treatment would be done by a high-tech sewage treatment plant in which microbes would break down the residue from mustard agent neutralization. The most noticeable byproduct from the mustard agent is thiodyglycol, a solvent commonly used in ballpoint pen ink. While the substance itself is not considered a major threat, the international chemical weapons treaty requires that the hydrolysate be broken down.

Earley outlined the process in which the hydrolysate would move from the neutralization plant into storage tanks and then treatment units where the chemicals would be broken down, much like wastes are digested by microbes in municipal treatment systems. The treated water would then be recycled back to the neutralization plant and the solid residue taken away for disposal in dumps used for hazardous waste.

Joan Sowinski of the Colorado Department of Public Health and Environment asked about mercury residue. Ironically, other weapons destruction plants destroying the more deadly nerve agent have had to install new air-filtering equipment when they start working on mustard agent because that substance gives off mercury when burned.

Earley said that tests of mustard agent hydrolysate have shown mercury levels that were barely detectable and that filters would trap any mercury released by the microbes.

Nevertheless, Ross Vincent, chairman of the working group, said, "This sounds like a question that bears some investigation."