Secondary formation of disinfection by-products by UV treatment of swimming pool water

Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters

“…A similar trend has been reported in freshwater pool studies (Cheema et al, 2017;Cimetiere and De Laat, 2014;Spiliotopoulou et al, 2015) and also in drinking water, where it has been observed that UV treatment increases the fraction of low molecular organic matter, which in turn increases chlorine consumption (Choi and Choi, 2010 (Feng et al, 2007;Watts and Linden, 2007), which then might react with organic matter present in the pool water. Thereby, non-chlorine reactive molecules may become highly reactive after UV treatment, thus leading to an observed increase in chlorine consumption.…”

“…These three pools are among pools studied in previous papers : Manasfi et al (2016) found a TOC value of 11 to 12 mg/L (due to heavy use and high frequentation in summer) and Parinet et al (2012) reported a TOC value of 2.0 to 3.6 mg/L (due to lower frequentation in winter), these latter being similar to ours (sampling in March). previous studies of freshwater pools (Cheema et al, 2017;Spiliotopoulou et al, 2015), and so no further investigations were included in this study. Bromide content varied between 75 and 88.5 mg/L in the three pools, representing a higher bromide content than found in the raw seawater used to fill these pools (72 mg/L).…”

“…Thereby, non-chlorine reactive molecules may become highly reactive after UV treatment, thus leading to an observed increase in chlorine consumption. Nonetheless, in a recent study, increased chlorine reactivity caused by radical oxidation was found to be insignificant compared with the increase resulting from UV radiation (Spiliotopoulou et al, 2015). Chlorine consumption (mg/L) Figure 1 Chlorine consumption after 24 h at 25°C.…”

“…However, as chloroform concentrations were close to or under the quantification limit, no definite trend was observed for chloroform. Spiliotopoulou et al (2015) reported that UV irradiation does not create chloroform in freshwater swimming pool waters, with or without free chlorine present, while Cassan et al (2006), Cimetiere and De Laat (2014) and Spiliotopoulou et al (2015) all reported chloroform formation as a result of chlorination following UV irradiation in freshwater pools.…”

“…However, reaction pathways promote the formation of some DBPs with UV, followed by chlorination. Spiliotopoulou et al (2015) described that DBPs are only formed in secondary reactions after chlorine addition during the post-UV chlorination treatment of freshwater pools. Cimetiere and De Laat (Cimetiere and De Laat, 2014) also reported increased the formation of some DBPs with UV treatment followed by chlorination in freshwater pools during the post-chlorination step.…”