Development and field testing of a mobile chlorine dioxide generation system for the decontamination of buildings contaminated with Bacillus anthracis.

The numerous buildings that became contaminated with Bacillus anthracis (the bacterium causing the disease anthrax) in 2001, and more recent B. anthracis - related events, point to the need to have effective decontamination technologies for buildings contaminated with biological threat agents. The U.S. Government developed a portable chlorine dioxide (ClO(2)) generation system to decontaminate buildings contaminated with B. anthracis spores, and this so-called mobile decontamination trailer (MDT) prototype was tested through a series of three field trials. The first test of the MDT was conducted at Fort McClellan in Anniston, AL. during October 2004. Four test attempts occurred over two weekends; however, a number of system problems resulted in termination of the activity prior to any ClO(2) introduction into the test building. After making several design enhancements and equipment changes, the MDT was subjected to a second test. During this test, extensive leak checks were made using argon and nitrogen in lieu of chlorine gas; each subsystem was checked for functionality, and the MDT was operated for 24h. This second test demonstrated the MDT flow and control systems functioned satisfactorily, and thus it was decided to proceed to a third, more challenging field trial. In the last field test, ClO(2) was generated and routed directly to the scrubber in a 12-h continuous run. Measurement of ClO(2) levels at the generator outlet showed that the desired production rate was not achieved. Additionally, only one of the two scrubbers performed adequately with regard to maintaining ClO(2) emissions below the limit. Numerous lessons were learned in the field trials of this ClO(2) decontamination technology.