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Published on: April 6, 2022
A new dual-collimation batch reactor for determination of ultraviolet inactivation rate constants for microorganisms
Stephen B Martin1, Elizabeth S Schauer2, David H Blum3
1Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Respiratory Health Division, Field Studies Branch, 1095 Willowdale Road, Morgantown, WV 26505, USA; Pennsylvania State University, College of Engineering, Department of Architectural Engineering, Indoor Environment Center, 104 Engineering Unit A, University Park, PA 16802, USA.
Abstract:
We developed, characterized, and tested a new dual-collimation aqueous UV reactor to improve the accuracy and consistency of aqueous k-value determinations. This new system is unique because it collimates UV energy from a single lamp in two opposite directions. The design provides two distinct advantages over traditional single-collimation systems: 1) real-time UV dose (fluence) determination; and 2) simple actinometric determination of a reactor factor that relates measured irradiance levels to actual irradiance levels experienced by the microbial suspension. This reactor factor replaces three of the four typical correction factors required for single-collimation reactors. Using this dual-collimation reactor, Bacillus subtilis spores demonstrated inactivation following the classic multi-hit model with k=0.1471cm(2)/mJ (with 95% confidence bounds of 0.1426 to 0.1516).
