Preliminary laboratory investigation of disinfection by-product precursor removal using an advanced oxidation process

Natural organic matter (NOM) is ubiquitous in surface and ground waters throughout the world. During drinking water treatment, the NOM that remains in treated water can react with chlorine to form disinfection by-products. It has been shown that titanium dioxide photocatalysis can achieve over 96% reduction in ultraviolet (UV)(254) absorbing species such as hydrophobic NOM and over 81% reduction in dissolved organic carbon (DOC). However, an additional filtration stage is required to recover the suspended catalyst before it is suitable for municipal drinking water application. To overcome this problem, we have used immobilised catalysts prepared using chemical sol-gels, and their performance has been assessed during bench-scale experiments. An immobilised catalyst enables in situ regeneration using UV light and subsequent reuse of the catalyst. In this research, titanium dioxide sol-gels have been used to coat substrates at a laboratory scale. Results showed that the various coatings prepared had different removal efficiencies for both DOC and UV254 absorbance. Maximum removals were 1.336 g/m(2) and 89%, respectively.