The events of 2001 and the continuing war on terrorism have made it clearer than ever that there is a real need for effective decontamination methods that can be used after an attack using biological warfare (BW) agents.
The Atmospheric Plasma Decontamination System
Atmospheric Glow Technologies, Inc. (AGT) is developing an innovative Atmospheric Plasma Decontamination (APD) System based upon the patented One Atmosphere Uniform Glow Discharge Plasma (OAUGDP®) technology. The APD system can be used to neutralize all microorganisms on a variety of equipment. Efforts funded by DoD Army SBIR Phase I and Phase II contracts proved the utility of the APD concept and led to the development of a prototype APD System that rapidly inactivates BW agent simulants placed on representative sensitive material without causing significant damage to that material.
There are numerous problems with current decontamination agents and methods, especially when sensitive material is considered. Harsh chemicals will likely damage such equipment, in addition to posing a risk to personnel and the environment. AGT's OAUGDP® technology uses plasma to produce reactive chemical species (RCS) from the constituents of ordinary air. These RCS are effective at neutralizing microorganisms, and the decontamination procedure does not subject the materiel to high temperatures, fluids, high electric fields or UV. Studies to date indicate little or no damage to many materials (most plastics, aluminum, stainless steel, glass, etc.). Additionally, most of the RCS are short-lived so little exhaust treatment is needed and no hazardous wastes are produced by the decontamination process.
The APD system has been tested extensively by AGT. It is able to achieve a 6 log reduction (or 99.9999%) in spore viability in only five minutes. In that form, the APD device is capable of decontaminating small areas or volumes in an open environment.
The APD Plasma Generator
The purple glow is the plasma inside the generator. Air is blown through the device, carrying RCS out of the plasma and to the area being treated. This test illustrates decontamination at a distance from the plasma. Paper strips inoculated with endospores (spore strips) located at various distances from the device are treated and the effectiveness determined by assessing spore viability.
An Atmospheric Plasma Decontamination (APD) system consists of the plasma generator which generates reactive chemical species from air, a high voltage (HV) power supply that drives the plasma, an air pump that supplies air to the generator and ultimately expels the reactive chemicals, a fluid cooler and pump to remove waste heat from the blower and a heat exchanger to cool the exhaust stream of reactive chemicals. The reactive chemicals in the exhaust stream are used to decontaminate items.
Figure 1. APD system diagram.
Page 2 of 6