Ultraviolet light-emitting diodes (UV-LEDs) have demonstrated the ability to inactivate microorganisms in water, offering an environmentally safer alternative to the conventional mercury lamp, in UV applications. While several studies have explored the microbiological effect of UVC-LEDs (200nm-280nm), limited information exists regarding their effects on waters with critical qualities. These critical qualities encompass bacteria, viruses, and protozoa – drinking water quality indicators defined by the World Health Organization for small water systems. For the first time, this work reports on the Escherichia coli, PhiX-174, MS2, and Cryptosporidium oocysts inactivation using a bench-scale UVC-LED (280 nm) water disinfection system. UV doses at a wavelength of 280 nm (UV280) of up to 143.4 mJ/cm2 were delivered under two quality-critical water conditions: filtered water (UV transmittance at 280 nm – UVT280 90.2 %) and WHO challenge water (UVT 15.7 %). Results revealed microbiological reductions dependent on exposure time and UVT. For UV280 dose of 16.1 mJ/cm2, 2.93-3.70 log E. coli reductions were observed in UVT 90.2 % and 15.7 %, 3.49-4.21 log for PhiX-174, 0.63-0.78 log for MS2, and 0.02-0.04 log for Cryptosporidium oocysts. Significantly higher UV280 doses of 143.4 mJ/cm2 led to reductions of 3.94-5.35 log for MS2 and 0.42-0.46 log for Cryptosporidium oocysts. Statistical analysis revealed that the sensitivity among the organisms to UV280 exposure was E. coli = PhiX-174 > MS2 >> Cryptosporidium oocysts. Although experiments with WHO challenge water posed greater challenges for achieving 1 log reduction compared to filtered water, this difference only proved statistically significant for PhiX-174 and MS2 reductions. Overall, UVC-LED technology demonstrated notable efficacy in microbiological inactivation, achieving significant reductions based on WHO scheme of evaluation for POU technologies in both bacteria and viruses even in critical-quality waters. The findings emphasize the potential for extending the application of UVC-LED as a viable solution for household water treatment.

中文翻译：

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UVC-LED 辐射对细菌、病毒和原生动物灭活的功效：暴露剂量和水质影响的评估


紫外线发光二极管 （UV-LED） 已证明能够灭活水中的微生物，在紫外线应用中为传统汞灯提供了一种更环保的替代方案。虽然有几项研究探讨了 UVC-LED （200nm-280nm） 的微生物效应，但关于它们对具有关键品质的水域的影响的信息有限。这些关键品质包括细菌、病毒和原生动物——世界卫生组织为小型水系统定义的饮用水质量指标。这项工作首次报道了使用台式 UVC-LED （280 nm） 水消毒系统对大肠杆菌、PhiX-174、MS2 和隐孢子虫卵囊的灭活。在两种质量关键水条件下，280 nm 波长 （UV280） 的紫外线剂量高达 143.4 mJ/cm2：过滤水（280 nm 紫外线透射率 – UVT280 90.2%）和 WHO 挑战水（UVT 15.7%）。结果显示，微生物减少取决于暴露时间和 UVT。对于 16.1 mJ/cm2 的 UV280 剂量，在 UVT 90.2 % 和 15.7% 中观察到大肠杆菌减少 2.93-3.70 log，PhiX-174 为 3.49-4.21 log，MS2 为 0.63-0.78 log，隐孢子虫卵囊为 0.02-0.04 log。143.4 mJ/cm2 的显着更高的 UV280 剂量导致 MS2 减少 3.94-5.35 log，隐孢子虫卵囊减少 0.42-0.46 log。统计分析显示，生物体对 UV280 暴露的敏感性为大肠杆菌 = PhiX-174 > MS2 >> 隐孢子虫卵囊。尽管与过滤水相比，使用 WHO 激发水的实验对实现 1 log 减少提出了更大的挑战，但这种差异仅证明 PhiX-174 和 MS2 减少具有统计学意义。 总体而言，UVC-LED 技术在微生物灭活方面表现出显着的功效，根据 WHO 对细菌和病毒的 POU 技术评估计划，即使在关键质量的水域中，也能显着减少细菌和病毒中的 POU 技术。研究结果强调了 UVC-LED 作为家庭水处理的可行解决方案扩展应用的潜力。