Pulsed-UV unit may inactivate biological agents

This article discusses tests on a pulsed‐ultraviolet (UV) disinfection unit that demonstrate it can deliver high germicidal dosages to effectively inactivate highly resistant known pathogens. These tests were done in anticipation of applying this unit to situations in which biological weapons may have been released into a water supply to a building or other facility as well as into small community water systems. Until now, little or no information has been available regarding continuous‐flow, dose‐delivery verification tests on commercial systems at dose levels approaching 250 mJ/cm2. Tests conducted at the Leesburg, Virginia, Pollution Control Facility on Sept. 17, 2002 challenged the system by varying water flow rates, pulse frequencies, and water transmittance levels. The tests were conducted to characterize as well as possible the ability of the system to deliver high germicidal dose levels that would be comparable to those required to effectively inactivate highly resistant, known pathogens. Estimated dose delivery was tested by challenging the disinfection unit with MS2 bacteriophage, the indicator organism used for verification tests for water and wastewater disinfection applications.