AWWA WQTC64108

An ultraviolet light coupled with titanium dioxide (UV/TiO₂) advanced oxidation pilot system was evaluated at the Greenbrook Water Treatment Plant. The objective of the pilot study was to evaluate the effect of varying operating parameters on the performance of the UV/TiO₂ system for the concurrent degradation of 1,4-dioxane and removal of iron and manganese through adsorption onto the TiO₂ surface. It was hypothesized that as iron and manganese adsorb onto the TiO₂ surface, the degradation of 1,4-dioxane would be impaired. This pilot study showed promising results that suggest UV/TiO₂ advanced oxidation is capable of concurrent treatment of multiple contaminants. Effective iron removal was achieved under all tested conditions, while the effective removal of manganese and degradation of 1,4-dioxane was dependent on operating conditions. A lower flow rate (8 L/min) was required for both the removal of manganese under alkaline conditions (pH 8.6), and the degradation of 1,4-dioxane under acidic conditions (pH 5.5) or in the presence of peroxide (30 mg/L). Thus, the pilot UV/TiO₂ system is able to concurrently remove iron with either manganese or 1,4-dioxane, but the effective removal of manganese and degradation of 1,4-dioxane are competing processes. Results suggest that a higher UV dose (lower flow rate, more UV lamps, or more powerful UV lamps) needs to be applied in order to effectively remove all three contaminants. Includes 26 references, figures.