A Simple and Practical Method for Fluence Determination in Bench‐Scale UV‐LED Setups

• Published in: Photochemistry and photobiology Vol. 99; no. 1; pp. 19 - 28
• Main Authors: Watanabe, Shinya, Oguma, Kumiko
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.01.2023
• Subjects: Actinometry; Disinfection; Disinfection - methods; Fluence; Light emitting diodes; Mathematical models; Mercury; Models, Theoretical; Pseudomonas aeruginosa; R&D; Research & development; Spectroradiometers; Ultraviolet radiation; Ultraviolet Rays; Water Purification - methods; Water treatment
• ISSN: 0031-8655; 1751-1097
• DOI: 10.1111/php.13668

ABSTRACT In UV disinfection of water, the fluence of UV required to inactivate a target microorganism is determined based on the procedures developed for conventional mercury‐based UV lamps with collimation. In this regard, a simple and practical method with a mathematical model and radiometry is proposed for determining the fluence rate with UV light‐emitting diodes (UV‐LEDs). This method was applied to a bench‐scale UV‐LED setup and validated by comparing the calculations with the measurements using either a spectroradiometer or a chemical actinometer. The results showed high accordance with spectroradiometer outputs with a linear regression equation y = 0.997x (x: model calculation, y: spectroradiometer output, r2 = 0.999, P < 0.001 for n = 20) in an experiment varying the distance between the measurement points and the UV‐LEDs. Meanwhile, the proposed method and chemical actinometry exhibited 98% concordance. Furthermore, this method was applied to determine the fluence‐response profiles of Pseudomonas aeruginosa, and the results demonstrated that the proposed method was appropriate at two different distances between the UV‐LEDs and the solutions. To conclude, the proposed method can determine the fluence in a UV‐LED bench‐scale setup in a simple and practical way, which would potentially promote the research and development of water treatment using UV‐LEDs. A simple and practical method with a mathematical model and radiometry is proposed for determining the fluence rate with UV light‐emitting diodes (UV‐LEDs) for UV disinfection of water. The mathematical model is expressed as a single equation considering optical effects such as reflection, absorption and divergence. This method was applied to a bench‐scale UV‐LED setup and validated by comparing the calculations with the measurements using either a spectroradiometer or a chemical actinometer.