Instantaneous Water Purification by Deep Ultraviolet Light in Water Waveguide: Escherichia Coli Bacteria Disinfection

Abstract

The necessity of small water purification equipment has been increasing in recent years as a result of frequent natural disasters. Ultraviolet (UV) radiation treatment is an effective method for the disinfection of bacterial contaminants in water. As an emerging technology, disinfection by deep-ultraviolet light-emitting diodes (DUV-LEDs) is promising. Few studies have used the point-source characteristics of LEDs and have instead replaced mercury vapor lamps with LEDs. Here, we demonstrate the instantaneous purification of contaminated water by combining the point source characteristics of DUV-LEDs with a water waveguide (WW). The principle is based on the WW region acting as an effective DUV disinfector, whereby a high UV dose in a confined WW region can be applied to bacterial contaminants in a short period of time (around one second). We demonstrate the effect of this DUV-LED WW disinfection technique by showing the results of 3-log disinfection levels of water contaminated with Escherichia coli bacteria after a short treatment time. We believe that the combination of the point-source nature of DUV-LED emission, the water-waveguide effect, and a small photovoltaic cell paves the way toward environmentally friendly and emergency preparedness portable water purification equipment that instantaneously supplies clean water just before drinking.

Transient photothermal inactivation of Escherichia coli stained with visible dyes by using a nanosecond pulsed laser

“…Inactivation with ultraviolet (UV) radiation is a well-established technique that has been used widely, including in the purification of water [1][2][3][4][5] , room decontamination 6,7 , and air purification. The wavelength of UV radiation used is generally shorter than 280 nm, which places it in the UVC region (the wavelength region from 250 to 280 nm is typically used); this wavelength is selected because UVC radiation inactivates pathogenic bacteria, viruses and other microorganisms [8][9][10] .…”

Perspectives on UVC LED: Its Progress and Application

“…With regard to the application of UVC LED to drinking water sterilization and disinfection, Matsumoto et al of Nagoya City University in Japan designed a device that uses water waveguide technology to improve the utilization efficiency of UVC radiation sources. As shown in Figure 9, UVC passes through the water waveguide; then, the water flow in the water pipe can be irradiated for a long time, which effectively improves sterilization efficiency [99].…”

“…With regard to the application of UVC LED to drinking water sterilization and disinfection, Matsumoto et al of Nagoya City University in Japan designed a device that uses water waveguide technology to improve the utilization efficiency of UVC radiation sources. As shown in Figure 9, UVC passes through the water waveguide; then, the water flow in the water pipe can be irradiated for a long time, which effectively improves sterilization efficiency [99]. In a research study on air sterilization using UV radiation, Rudnick et al from Harvard University in the United States determined that a UV sterilization device in a heating ventilation, and air conditioning (HVAC) appliance is more efficient than a portable one [100].…”

A Systematic Review on Advancements in Drinking Water Disinfection Technologies: A Sustainable Development Perspective

“…Therefore, to solve these problems associated with the current water treatment system thrust to do further research in this field. (50). Newly emerged technology that is Ultraviolet light-emitting diodes (UV-LEDs) is poorly characterized in full-scale drinking water treatment systems and hence Peter Jarvis et al,2019 investigated UV-LED reactor that is world's first full-scale UV-LED reactor for cleansing of pathogenic microbes from drinking water (54).…”