In order to reduce the release of micropollutants into water bodies as well as for their elimination, there is no single way but multiple different solutions are necessary. The combination of measures needs to be applied at multiple stages within the water cycle. In other words numerous “barriers” against micropollutants need to be installed, which leads the approach to be defined as “multi-barrier concept”.
The definition of the multi-barrier concept has been initiated by the research programme „Reine Ruhr“. The key message of the concept states that for an efficient reduction of micropollutants actions must be taken at the source, during the wastewater treatment, and during the drinking water treatment.
Measures at the source
This refers to measures, which prevent or reduce the entry of micropollutants into the environment on the level of production and utilisation. Examples for these measures are substitution of compounds during production processes and the proper disposal of pharmaceuticals via household garbage and not via sink or toilet.
Measures during wastewater treatment
Most of the micropollutants enter surface waters via sewer networks and municipal WWTP. Therefore, the upgrade of WWTP with suitable techniques is considered as a very important measure to reduce micropollutants in the environment. Typical technical upgrades include adsorption by activated carbon and ozonation.
Measures during drinking water purification
The release of micropollutants from WWTP cannot be completely prevented. Furthermore, micropollutants such as pesticides from agricultural practices, enter surface water and groundwater bodies also through diffuse sources. In NRW, raw water for drinking water treatment originates from bank filtration and groundwater. Therefore, actions must be taken also during drinking water treatment in order to eliminate micropollutants from drinking water.