Implementation of advanced micropollutants removal technologies in wastewater treatment plants (WWTPs) - Examples and challenges based on selected EU countries

The accumulation of micropollutants (MPs) and their increasing concentration in the aquatic environment are an emerging issue for water quality in the world. The complex web of exposure pathways, as well as the variety in the chemical structure and potency of MPs, represents enormous challenges for researchers and policy initiatives. In order to manage MPs, it has to be decided which of them have to be reduced and to what extent, where in the water cycle this would be the most efficient and which technical means that should be applied to be sustainable. All of these aspects require a knowledge of MPs abundance, properties, fate and impact in the environment, which is essentially determined by two related features: the sources and the physico-chemical characteristics of MPs. Micropollutants including pharmaceuticals, antibiotics and hormones can enter the aquatic environment through both diffuse and point sources, but in urbanised regions wastewater treatment plants (WWTPs) play a crucial role in their dissemination. Conventional WWTPs are effective in removal of macropollutants (e.g. nutrients, suspended solids and some trace elements), while MPs may go through the treatment unchanged or be removed at different rates. Most of the EU countries are convinced that the presence of MPs in the environment poses a serious problem, particularly in highly populated regions where surface water resources serve as a source of potable water. Presently, various technical solutions are available and have been proven possible to integrate with existing treatment processes in an expedient manner. The solutions that have been evaluated are mainly based on ozonation and/or activated carbon treatment technologies which may definitely be considered the most effective compared to the costs incurred.