Improved Drinking Water Disinfection with UVC-LEDs for Escherichia Coli and Bacillus Subtilis Utilizing Quartz Tubes as Light Guide

Water

Andrej Gross¹  Felix Stangl²  Katharina Hoenes²  Michael Sift²  Martin Hessling¹ 

[1] Institute of Medical Engineering and Mechatronics, Ulm–University of Applied Sciences, Ulm 89081, Germany;

关键词: drinking-water;    disinfection;    UVC-light guidance;    UVC-disinfection reactor;   

DOI  :  10.3390/w7094605

来源: mdpi

【 摘 要 】

A new approach is investigated utilizing light guidance capabilities of optical pure quartz glass in order to maximize drinking water disinfection efficiency with UVC-light-emitting diodes (LEDs). Two experimental setups consisting of soda-lime AR^® glass (VWR, Darmstadt, Germany) or HSQ^® 100 quartz glass (Heraeus, Wasserburg, Germany) reactors were designed to compare disinfection rates with and without total reflection of UVC radiation along the reactor walls. Each reactor was filled with 9 mL bacteria samples containing either E. coli DSM (Deutsche Sammlung von Mikroorganismen) 498 or B. subtilis DSM 402 strains (concentration 1–3 × 10⁶ colony forming units (CFU)/mL) with and without additional mixing and irradiation periods of 10, 40, and 90 s. Disinfection rates were increased up to 0.95 log₁₀ (E. coli) and 0.75 log₁₀ (B. subtilis) by the light guide approach in stagnant samples. The same experiments with mixing of the samples resulted in an increased disinfection efficiency of 3.07 log₁₀ (E. coli) and 1.59 log₁₀ (B. subtilis). Optical calculations determine that total reflection is achieved with the applied UVC-LED’s viewing angle of 15°. Furthermore measurements show that HSQ^® 100 quartz has a transmittance of 92% at 280 nm UVC irradiation compared to the transmittance of soda-lime glass of 2% (1 mm wall thickness).

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.