Contrasting the effectiveness of chloramines reduction in indoor swimming pools disinfected by ozone versus UV
Objectives: Chloramines are disinfection by-products that are produced between chlorine and contaminants in the pool. Exposures to chloramines at high levels or for extended durations have been found to cause mucous membrane irritations and respiratory distress in humans. To reduce chloramines production, secondary treatment in the form of UV and ozone are used in newer indoor swimming pools. This study aimed to examine whether there is a difference between UV and ozone treatment in their effectiveness in reducing chloramines in indoor pools. Killarney leisure pool and whirlpool, which utilized ozone treatment, as well as Hillcrest leisure pool and whirlpool, which utilized UV treatment, were studied. Methods: Hach Pocket Colorimeter 2 Analysis System which used a DPD method of analysis was used to determine concentrations of free chlorine and total chlorines. Concentrations of chloramines were calculated by subtracting the concentration of free chlorine from total chlorine. Thirty pool water samples for each type of pool system were analyzed on random days in the afternoons of January and February, 2015. A two sample t-test was used to compare the chloramines concentrations of the whirlpools; while a Mann-Whitney U test was used to compare the chloramines concentrations of the leisure pools. Results: There was a statistically significant difference between the mean chloramines concentration of the UV-treated whirlpool and that of the ozone-treated whirlpool (p = 0.00854). However, there was not a statistically significant difference between the mean chloramines concentration between the UV treated leisure pool and that of the ozone treated leisure pool (p = 0.882048). Conclusions: It was determined that UV was more effective than ozone in reducing chloramines concentrations in indoor public whirlpools. Therefore, in order to choose a treatment that leads to the greatest reduction of health hazard posed to pool patrons, UV is preferred. Whirlpools that intend to adopt secondary treatment may consider UV.