Effect of Microporous Filtration Media and Tidal Flow Condition on Disinfection Efficiency of Filtration Bed Immobilized with Nanosilver

Abstract

The objective of this study is to develop a disinfection system independent of chlorine and energy, that is, electricity or light. Thus a filtration bed immobilized with nanosilver which can generate active oxygen, a sterilization agent, independent of light was proposed. Among seven kinds of filtration media immobilized with nanosilver, pumice, charcoal and zeolite gave the best three high disinfection efficiency, suggesting a microporous filtration media is suitable to exhibit disinfection effect of nanosilver. The effect of tidal flow condition, that is unsaturated and saturated time, on disinfection efficiency was investigated by continuous disinfection tests using a packed bed column with pumice immobilized with nanosilver. It was found that unsaturated time needed to generate active oxygen was more important than saturated time needed for disinfection by filtration media immobilized with nanosilver and a longer unsaturated time gave higher disinfection efficiency. Since the disinfection efficiency was maintained after the total number of times of disinfection treatment reached one hundred, persistence of disinfection effect of nanosiliver immobilize on pumice was confirmed. These results demonstrated enough possibility of the disinfection system independent of chlorine and energy with a filtration bed immobilized with nanosilver.