title: Evaluating UV-C LED disinfection performance and investigating potential dual-wavelength synergy.
abstract: A dual-wavelength UV-C LED unit, emitting at peaks of 260 nm, 280 nm, and the combination of 260|280 nm together was evaluated for its inactivation efficacy and energy efficiency at disinfecting Escherichia coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores, compared to conventional low-pressure and medium-pressure UV mercury vapor lamps. The dual-wavelength unit was also used to measure potential synergistic effects of multiple wavelengths on bacterial and viral inactivation and DNA and RNA damage. All five UV sources demonstrated similar inactivation of E. coli. For MS2, the 260 nm LED was most effective. For HAdV2 and B. pumilus, the MP UV lamp was most effective. When measuring electrical energy per order of reduction, the LP UV lamp was most efficient for inactivating E. coli and MS2; the LP UV and MP UV mercury lamps were equally efficient for HAdV2 and B. pumilus spores. Among the UV-C LEDs, there was no statistical difference in electrical efficiency for inactivating MS2, HAdV2, and B. pumilus spores. The 260 nm and 260|280 nm LEDs had a statistical energy advantage for E. coli inactivation. For UV-C LEDs to match the electrical efficiency per order of log reduction of conventional LP UV sources, they must reach efficiencies of 25-39% or be improved on by smart reactor design. No dual wavelength synergies were detected for bacterial and viral inactivation nor for DNA and RNA damage.
authors.affiliation: Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO 80309, USA.
authors.forename: Sara E
authors.initials: SE
authors.lastname: Beck
authors.affiliation: United States Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA.
authors.forename: Hodon
authors.initials: H
authors.lastname: Ryu
authors.affiliation: United States Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Boczek
authors.affiliation: United States Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Cashdollar
authors.affiliation: Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO 80309, USA.
authors.forename: Kaitlyn M
authors.initials: KM
authors.lastname: Jeanis
authors.affiliation: Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO 80309, USA.
authors.forename: James S
authors.initials: JS
authors.lastname: Rosenblum
authors.affiliation: AquiSense Technologies, 11941 Oxford Hills Drive, Walton, KY 41094, USA.
authors.forename: Oliver R
authors.initials: OR
authors.lastname: Lawal
authors.affiliation: Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO 80309, USA. Electronic address: karl.linden@colorado.edu.
authors.forename: Karl G
authors.initials: KG
authors.lastname: Linden
mesh_terms: D004203:Disinfection; D004926:Escherichia coli; D006801:Humans; D017909:Levivirus; D014466:Ultraviolet Rays; D018508:Water Purification
keywords: Bacillus pumilus spores; Combined wavelengths; Electrical energy per order; Human adenovirus type 2; Nucleic acid damage