Taste & Odour

Team
Urs von Gunten, Andreas Peter

Goal
Assessment and treatment of taste and odor problems.

Description
Taste and odor (T&O) problems are the reason for most consumer complaints in water utilities. Frequently, the assessment of these problems is difficult and time consuming and they are traditionally addressed by multi barrier systems for surface water treatment.

The identification of odorants is well understood for two groups of chemicals: chlorinous/ozonous and earthy/musty. In the last ten years also other types of odors have been identified by sophisticated analytical tools in combination with sensory analysis. However, there is still a lack of identification of compounds that cause T&O problems. One of the difficulties arises in systems where mixtures of compounds below the individual threshold concentration are present. Types of compounds which are just emerging include chlorinated/brominated phenols and anisols. More kinetic information is needed to fully describe their formation and treatment. Among the natural products, in Switzerland, algae/bacteria derived compounds have the highest priority. The most important compounds are geosmin and methyl-isoborneol (MIB), which are also found in lake Zürich. An assessment of the current situation in Switzerland will be made.

It is clear from the literature that taste and odor problems are extremely complex and require a high level of instrumentation and expertise to be fully addressed. Because of the enormous task to tackle T&O problems in their full complexity, a solution oriented approach has been chosen within the framework of this work package. It should lead to an assessment of water treatment processes with regard to the removal/formation of selected T&O compounds.