Oxidation Kinetics of Selected Taste and Odor Compounds During Ozonation of Drinking Water

The applicability of ozonation to mitigate taste and odor problems in drinking water was investigated. Second-order rate constants of eleven taste and odor compounds with ozone and hydroxyl radicals were determined under laboratory conditions. Measured rate constants for the reaction with hydroxyl radicals are between 3 × 109 and 1010 M-1s-1 and for ozone: kβ-cyclocitral = 3890 ± 140 M-1s-1; kgeosmin = 0.10 ± 0.03 M-1s-1; k3-hexen-1-ol = 5.4 ± 0.5 × 105 M-1s-1; kβ-ionone = 1.6 ± 0.13 × 105 M-1s-1; k2-isopropyl-3-methoxypyrazine = 50 ± 3 M-1s-1; k2-methylisoborneol = 0.35 ± 0.06 M-1s-1; k2,6-nonadienal = 8.7 ± 0.4 × 105 M-1s-1; k1-penten-3-one = 5.9 ± 0.1 × 104 M-1s-1; k2,6-di-tert-butyl-4-methylphenol (BHT) = 7.4 ± 0.2 × 104 M-1s-1; k2,4,6-tribromoanisole = 0.02 ± 0.01 M-1s-1; k2,4,6-trichloroanisole = 0.06 ± 0.01 M-1s-1. Experiments conducted in natural waters showed that the removal efficiency during ozonation can be reliably predicted with the determined second-order rate constants. Ozonation is a powerful tool capable of oxidizing most of the taste and odor compounds to more than 50% under typical drinking water treatment conditions. For ozone-resistant taste and odor compounds, the application of advanced oxidation processes may be appropriate.