Occurrence and Fate of Fragrances in Wastewater Treatment Plants

Fragrance loading in urban domestic wastewaters and their behavior in a conventional wastewater treatment plant (WWTP) were discussed. From the data collected worldwide, the inputs, concentrations, and removal ratios of total fragrances varied in several orders of magnitude, while for each compound, the data variation was within one or two orders of magnitude. This is considered to be fairly stable since these are “emerging” chemicals which normally occur in very low levels and mainly in household products. And, it would possibly reflect the commonness of the socio-economic patterns, i.e., the usage of household products and the biological situation in the treatment plants. In the last part of this chapter, the behavior of HHCB and AHTN (the predominant fragrances) in WWTPs was reviewed. The most important process for their removal from wastewater is the sorption to sewage sludge. For the other relevant mechanisms, such as biodegradation and volatilization, the tendency seemed diverse, with studies lacking consensus. The solid–water partitioning is an important basic physicochemical parameter to consider for the removal through sludge and for the effectiveness of biodegradation. The partitioning in the treatment steps was discussed in relation to their octanol-water partition coefficient (Kow), and in most cases, the observed partitions were substantially lower than those predicted by Kow, which urges for further theoretical studies.