Photolytic removal of DBPs by medium pressure UV in swimming pool water

Abstract

Medium pressure UV is used for controlling the concentration of combined chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported to be found in swimming pool water: chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetonitrile, bromochloroacetonitrile, dibromoacetronitrile, trichloroacetonitrile, trichloronitromethane, dichloropropanone, trichloropropanone, and chloral hydrate. First order photolysis constants ranged 26-fold from 0.020 min Using the UV removal of combined chlorine as an actinometer, the rate constants were recalculated to actual treatment doses of UV applied in a swimming pool. In an investigated public pool the UV dose was equivalent to an applied electrical energy of 1.34 kWh m . It was predicted thus that a beneficial side-effect of applying UV for removing combined chlorine from the pool water could be a significant removal of trichloronitromethane, chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes.

Effect of ozonation of swimming pool water on formation of volatile disinfection by-products – A laboratory study

“…Analyses were performed as previously described by [18]. Samples were analyzed by purge and trap (purge temperature = 30 °C, Velocity XPT Purge and Trap Sample Concentrator, Teledyne Tekmar, with autosampler: AQUATek 70, Teledyne Tekmar) coupled with a GC-MS (HP 6890 Series GC System, 5973 Mass selective detector, Hewlett Packard).…”

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

“…Overall, concentrations of HAA decreased by post-UV chlorination, which is likely due to the direct photolysis of the HAA, as all HAA found in the pool water contained bromine, and bromine containing DBP in swimming pool water is generally easily photolysed by UV (Hansen et al, 2013a). Studies with other water types have also described that brominated HAA is photolysed by UV treatment (Jo et al, 2011).…”

“…In this work, the UV dose was determined according to the method described by Hansen et al (2013a). A UV exposure cylindrical reactor setup was correlated to the real flow-through system on the pool by using combined chlorine as an actinometer.…”

“…A UV exposure cylindrical reactor setup was correlated to the real flow-through system on the pool by using combined chlorine as an actinometer. A UV system requires 1.0 kWh/m 3 to remove 90% of combined chlorine and 0.61 kWh/m 3 to remove monochloramine (Hansen et al, 2013a). The required radiation time for the cylindrical reactor setup to remove 90% of the monochloramine from the pool sample was 4.2 min (2.1 J/cm 2 ).…”

“…An established method employed to reduce combined chlorine in swimming pool water is direct photolysis by UV (Hansen et al, 2013a). The combined application of UV and chlorination provides opportunities for the formation of hydroxyl radicals as reactive intermediates (Feng et al, 2007).…”