AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
High Temperature Short-Time Infrared Disinfection of Bioaerosols
BRIAN DAMIT, Chang-Yu Wu, University of Florida
Abstract Number: 403 Working Group: Homeland Security
Abstract With growing concerns about bioterrorism and flu pandemics, the control of pathogenic bioaerosols has been given increasing attention. Recently, researchers have investigated the use of high temperature short-time (HTST) treatment to control bioaerosols. Although HTST treatment was shown to be effective, previous studies had the limitations of insufficient detection, inadequate temperature exposure characterization, and impracticality. To address these issues, a bioaerosol disinfection technology which uses infrared (IR)-generated HTST treatment was developed in this study. With this technology, bioaerosols were uniformly subjected to ultra-high temperatures (> 450 C) for just milliseconds.
The system consisted of a porous activated carbon cloth which was positioned normal to bioaerosol-laden air flow. The low pressure drop cloth was absorptive to IR and was readily heated by IR irradiation. By using a 250-W IR bulb, cloth temperatures in excess of 450 C were achieved in a few seconds for a face velocity of 5.3 cm/s. With this face velocity, the bioaerosol residence time in the pores of the heated cloth was 2 ms. Escherichia coli and MS2 virus were tested to represent pathogenic bacteria and virus bioaerosols respectively. The test microbes were aerosolized and downstream concentrations were sampled with and without HTST treatment.
With HTST treatment, greater than 99.99% and 99.999% efficiency was achieved for virus and bacteria respectively. This proved that bioaerosols can be inactivated in milliseconds provided sufficient temperature. A lower face velocity resulted in greater inactivation due to higher cloth temperature and increased residence time in the cloth. Unlike other studies where large heating coils were used, the IR technology forced bioaerosols to pass through the cloth pores and thus very close to the super-heated cloth fibers. In this case, the bulk flow did not need to be heated. The results demonstrate the potential of the IR technology in reducing viable bioaerosol concentrations.