Treatment of drinking water by UV/Cl2: a study of β-cyclocitral, a cyanobacterial taste & odor compound.

Homogeneous photocatalytic processes are receiving increased interest with regards to drinking water treatment for emerging pollutants. Especially the UV/Cl2 technique has a potential for real large-scale applications as it can combine disinfection with chemical oxidation using processes that are more familiar and widely applied by water supplies. However, more research is needed to understand the complex mechanisms involved, including formation of hydroxyl and chlorine radicals among others, as well as overall performance against various groups of emerging pollutants, such as the less-studied water taste and odor compounds (T&O) (Antonopoulou et al., 2014). We present results on the UV/Cl2 degradation of β-cyclocitral as a model of common cyanobacterial terpenoid T&O in water (Kaloudis et al., 2016). The study was conducted using a novel photoreactor set-up with custom-made UV-LED arrays, precise control of irradiance, continuous spectrophotometric – GC/MS monitoring and sensory evaluation of the process (Kaloudis et al. 2018). Effects of key process parameters i.e. irradiance, concentration of Cl2 and β-cyclocitral, water matrix (ultrapure and typical drinking water) on the kinetics as well as key degradation products and proposed pathways are presented. Effectiveness, efficiency and prospects of real applications of UV/Cl2 for removal of hazardous T&O from drinking water are discussed.