Material and Design Considerations for a Portable Ultra-Violet (UV) Light Emitting Diode (LED) Water Purification Device

Department of Defense personnel often deploy to austere environments where clean water is not readily available. Ultraviolet (UV) radiation through the use of light emitting diodes (LEDs) in a portable device offers a potential method for expedient water treatment. This research studied the application of one diode, low power, UV LEDs and nine diode, high power, UV LEDs within a portable steel reactor and Teflon reactors of three different wall thicknesses. Reactor efficiency was determined through measuring and comparing the rate constants for Advanced Oxidation of hydrogen peroxide with yellow tartrazine as a witness dye. Experiments conducted with low power UV LEDs indicate that the medium thickness reactor has a statistically significant higher rate constant than the steel and thin cylinder reactors. All high power UV LED tests had rate constants ten times higher than the low UV LEDs, but exhibited no significant difference between materials or thicknesses. Additionally, this research examined the microorganism inactivation in the optimum reactor by exposing E. coli to UV radiation. The experiments demonstrated complete reduction of E. coli at a flow rate up to 15 mL/min, and a 2-Log reduction at 20 mL/min, thus demonstrating proof of concept for future portable UV LED disinfection units