title: Effects of Arrangement of UV Light-Emitting Diodes on the Inactivation Efficiency of Microorganisms in Water.
abstract: Ultraviolet light-emitting diodes (UV-LEDs) offer high flexibility in the reactor design for water disinfection. To specify the key design factors affecting the performance of a reactor, we examined how the arrangement of UV-LEDs in a cylindrical reactor affects the inactivation efficiency of Escherichia coli and coliphage Qβ. A ring-shaped UV-LED apparatus, composed of two units containing ten 285-nm UV-LEDs each, were attached to a quartz cylinder, and microbial suspensions flowed through the cylinder for single pass at altered flow rates. The distance between the two units, L, was altered to examine its effects on inactivation efficiencies. Over 4 log inactivation of E. coli was achieved at 800 mL min-1regardless of the L values, suggesting that the apparatus has a high potential to disinfect water. The inactivation at L = 20 mm was significantly higher than that at L = 0 in all cases tested (ANOVA, P < 0.05), while this was not true when L was extended to 40 and 60 mm. Therefore, a separate arrangement of UV-LEDs at a certain distance can improve the efficiency, and the distance matters to enhance the performance. This study involves a design concept on how to arrange UV-LEDs in a water disinfection apparatus.
authors.affiliation: Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Oguma
authors.affiliation: Department of Urban Engineering, The University of Tokyo, Tokyo, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kita
authors.affiliation: Department of Urban Engineering, The University of Tokyo, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takizawa
mesh_terms: D017908:Allolevivirus / Q000528:radiation effects*; D004203:Disinfection / Q000379:methods*; D004926:Escherichia coli / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014871:Water Microbiology