Action Spectra of Bacteria and Purification of Pollutant Water at Faucets Using a Water Waveguide Method

Ultraviolet (UV) radiation treatment is an effective method for purifying pollutant water contaminated with bacteria and/or chemicals. As emerging technology, purification by deep ultraviolet light-emitting diodes (DUV-LEDs) promising. Few studies have used the point-source characteristics of LEDs and instead replaced mercury vapor lamps LEDs. Here, we show our recent progress in instantaneous combining DUV-LEDs a waveguide (WW). Before demonstration, determined efficacy disinfection as function irradiation wavelength (action spectra) constructing tunable DUV light source. We found that, wavelength, there strong correlation between dose-based inactivation rate constants deoxyribonucleic acid (DNA) absorbance. Based on this correlation, emission 265 nm was most disinfecting bacteria. Instantaneous 2-log levels Escherichia coli O1 or Pseudomonas aeruginosa were demonstrated using DUV-LED WW method. also discuss how far-UVC shorter than 230 nm, which has recently been attracting attention known safe human body, cannot give higher-dose-based constant compared to that due larger absorption coefficient nm.