Mercury vapor lamps, traditionally used for ultraviolet (UV) light treatment, have drawbacks due to their inefficiency and hazardous materials. UV light-emitting diodes (UV-LEDs) offer a safer and more efficient alternative. Transitioning to UV-LEDs can improve water disinfection reliability and sustainability for public health protection. However, further research is required to assess the effectiveness of UV-LEDs in inactivating less-studied organisms like fungal spores in drinking water.
This study employed a collimated UV-LED reactor to assess the inactivation and reactivation of Aspergillus niger and Penicillium sp. spores through UV radiation. The study explored the impact of different wavelengths (265 nm and 280 nm) and post-treatment conditions (light and dark) on treatment effectiveness. A kinetic model was utilized to determine UV resistance and damage repair capacity in the studied strains. Results indicated that post-treatment conditions and wavelength significantly influenced treatment efficacy for Penicillium sp. Conversely, for A. niger, post-treatment conditions played a more substantial role. A. niger displayed greater resistance than Penicillium sp., with D2 values (UV dose required to achieve 99% inactivation) of 323.7 ± 90 mJ cm-2 and 321.9 ± 43.8 mJ cm-2 at wavelengths of 265 nm and 280 nm, respectively. Penicillium sp. required 167.7 ± 13 mJ cm-2 and 146.5 ± 29.2 mJ cm-2 for wavelengths of 265 nm and 280 nm, respectively. These findings emphasize the importance of considering species-specific characteristics and post-treatment conditions in UV disinfection processes, particularly when dealing with less-studied organisms like fungal spores in drinking water. The transition to UV-LED technology holds promise for improving water treatment processes.