Evaluation of Ozonated Water and Ultraviolet Light Water Treatments on Bacillus subtilis Spore Efficacy in Spiked Water Samples

The goal of this water treatment study was to evaluate the effects of ozonated water and ultraviolet light (100–280 nm) on the efficacy of Bacillus subtilis spores. These water treatments are based on the current research for sanitizing bio-contaminated water. However, this study focused on small-scale water treatment units that could be modified or custom-built for a mobile sanitation system used for cleaning field equipment. The factorial study included four factors, resulting in a total of 16 water treatments. The ultraviolet light water treatment (UVC + UVC), with a total exposure time of 60 minutes, resulted in a log10 reduction of 3.51, equivalent to a 99.9% reduction in viable spores. The average spore reduction from UVC treatment increases with exposure time, then reaches an asymptotic plateau between 30 and 60 minutes. The combination of ozonated water with UV radiation yielded promising results in reducing spores. Wastewater technology, based on UVC systems, may be implemented with both mobile power washing systems. Additionally, larger units are required to effectively sterilize bio-contaminated wastewater within farms and storage facilities in the agricultural industry.