Co-occurrence of odor-causing dioxanes and dioxolanes with bis(2-chloro-1-methylethyl) ether in Huangpu River source water and fates in O-BAC process.

In recent years, dioxanes and dioxolanes have been intermittently detected in water environment and have caused several offensive drinking water odor incidents worldwide. In this study, the co-occurrence of eight dioxanes, twelve dioxolanes and bis(2-chloro-1-methylethyl) ether was investigated in Huangpu River watershed to explore potential sources and contributions to septic/chemical odor. Totally 8 dioxanes and dioxolanes were detected in river, with 1,4-dioxane (212 -8310 ng/L) and 2,5,5-trimethyl-1,3-dioxane (n.d.-133 ng/L) as the dominated dioxanes, 2-methyl-1,3-dioxolane (49.5 -2278 ng/L), 2-ethy-4-methyl-1,3-dioxolane (n.d.-167 ng/L) and 1,3-dioxolane (n.d.-225 ng/L) as the major dioxolanes. Bis(2-chloro-1-methylethyl) ether was detected (n.d.-1094 ng/L) with significant correlation with dioxanes and dioxolanes, illustrating their similar polyester resin-related industrial origins. 2-Ethy-4-methyl-1,3-dioxolane, 2,5,5-trimethyl-1,3-dioxane and bis(2-chloro-1-methylethyl) ether with individual maximum odor activity value above 1, should contribute to septic/chemical odor in Huangpu River water. The increased concentrations of these chemicals in the downstream of some industrial areas illustrated the association with industrial discharge. Fates in a waterworks using the river water as source water were further explored. The adopting ozone-biological activated carbon treatment could permit a relatively high removal for bis(2-chloro-1-methylethyl) ether and 2,5,5-trimethyl-1,3-dioxane (> 80%), while limited removal for other chemicals. This study provides valuable information for the management of drinking source water and water environment.