Advanced Wastewater Treatment by Ozonation for Abatement of Micropollutants from Municipal Wastewater Effluents

Municipal wastewater treatment plants are important contributors to the discharge of micropollutants to the aquatic environment. Therefore, in Switzerland it has been decided to treat the water at these point sources to reduce the discharge of micropollutants from municipal wastewater effluents. A team of scientists at Eawag has evaluated treatment options, which need to be readily available, easily applicable, and cheap. Based on a rigorous assessment, activated carbon-based processes and ozonation were selected. In this paper the focus is on ozonation, and the different aspects of its application are discussed, including kinetics and mechanisms for ozone reactions with micropollutants and matrix components, formation, and fate of transformation products in biological post-filtration and toxicological aspects. Finally, upgrading of ozonation is described including outreach of this approach to other countries.