| Abstract: | Some North American manufacturers are selling devices which produce ozone from UV radiation, which is pumped or sucked into spas, presumably to disinfect the water, without having to use chlorine. To test this claim, a private spa used by two people at least once a day was equipped with a UV radiation unit and an ozone (generating by UV) unit. Bacterial analyses were conducted during experiments carried out using chlorine alone, ozone generated by UV radiation, unit and an ozone (generating by UV) unit. Bacterial analyses were conducted during experiments carried out using chlorine alone, ozone generaed by UV radiation, and ozoen in combination with UV radiation. Heterotrophic plate counts, and counts of Staphyiococcus aureus and Pseudomonas aeruginosa were lowest when using chlorine, next lowest when using ozone #x002B; UV radiation, and highest when using UV-generated ozone. It is concluded that insufficient dissolved ozone is present for a sufficient reaction time to effect disinfection of these organisms by ozone generated by UV radiation. The fact that the odor of ozone was present above the spa water indicates that contacting also was inefficient. |
