Inactivation of fungal spores using household BDD device as a POU purification device: Application evaluation, influencing factors, and mechanisms

Abstract

Fungal contamination is commonly found in water supply systems, with filamentous fungi posing a particular threat through secondary pollution and potential risks to drinking water safety. In this study, an electrolytic device, with boron-doped diamond (BDD) as the anode material, was proposed for use as a point-of-use (POU) water treatment device to address the fungal contamination in tap water. The BDD device was found to effectively inactivate Aspergillus terrestris spores under different processing current intensities, water hardness, and alkalinity conditions. Moreover, in practical tap water applications, it also exhibited effective inactivation of Aspergillus terrestris spores and good efficiency in removing antibiotic-resistant genes (ARGs). During the electrolysis, various active species are produced, including ozone, reactive chlorine, and extracellular reactive oxygen species (eROS) such as •OH, •O2− and •1O2. Addtionally, spores produce excessive intracellular reactive oxygen species (iROS) under stimulus. These species could damage the cell membrane, resulting in DNA and TN leakage, a decrease in cellular ATP content, and destruction of surface morphology. This study provides a novel solution for eliminating fungal contamination in water endpoints.