Application of Supercritical CO₂ Bubbling to Deodorizing of Drinking Water

Abstract

We attempted to remove musty odor causing components in drinking water by a method of continuous flow extraction using microbubbles of supercritical carbon dioxide (SC-CO₂ method), which has been developed as an extraction technique for volatile compounds from foods. Both the SC-CO₂ method (10MPa, 35°C, 39% CO₂/sample flow rate, 7min exposure time) and a powdered activated carbon method were effective in removing more than 90% of the two musty odor components, 1,2,7,7-tetramethylnorbornan-2-ol (2-methyl isoborneol ; 2-MIB) and Geosmin (GEO), in the prepared model water. Moreover, foul odors such as the sludgy odor of actual reservoir and city tap water samples were almost completely destroyed by the SC-CO₂ method (20MPa, 35°C, 71% CO₂/sample flow rate, 13min exposure time). Thus, we concluded that the SC-CO₂ method was very effective for removing foul odor components of water such as those that produce a musty odor.