Swiss strategy against micropollutants

1 October 2009

Last Thursday, the Swiss Federal Office for the Environment (FOEN) presented its synthesis report on the MicroPoll project, in which Eawag played a major role, to the media. The conclusion drawn by the chief Swiss environmental authority in the report is that retrofitting 100 wastewater treatment plants is the most effective way of preventing contamination from micropollutants in urban drainage systems. Complementary to this, measures are also needed to reduce contamination at the source.

Roughly 100 wastewater treatment plants will need to be retrofitted with systems for eliminating micropollutants. This was the conclusion reached by the Federal Office for the Environment (FOEN) after completing investigations launched in 2006. Wastewater treatment plants do not remove micropollutants in sufficient quantities from the water. These have a detrimental effect on plants and aquatic life, and endanger our drinking water supplies. The micropollutants generally consist of biocide residues (herbicides, fungicides), medicines, cosmetics and cleaning agents. Even in very low concentrations they can have adverse effects on the environment. They also pass through wastewater treatment plants and water courses and end up in the lakes and groundwater.

A synthesis of more than 13,000 measurements of micropollutants carried out across Switzerland and the modelling system introduced within the scope of the «Strategie MicroPoll» project for over 10 selected micropollutants confirmed that pharmaceutical residues have a detrimental on aquatic organisms. The detrimental effect of endocrine disruptors was already established through the National Research Programme NFP 50.

Large wastewater treatment plants in particular

Wastewater treatment plants situated at river sections, which do not sufficiently dilute the treated wastewater in the river courses, or plants located at water bodies used for extracting drinking water must be equipped with appropriate purification systems. FOEN estimates that around 100 of the 700 existing wastewater treatment systems in Switzerland will need to be retrofitted. In addition to the largest plants in the country, this also includes 90 medium-sized treatment plants.

Organisational and technical measures

Within the scope of the MicroPoll project, a number of organisational and technical measures were investigated. Urban drainage systems could be cleansed more effectively by merging smaller wastewater treatment plants with larger ones. This could make wastewater purification more professional and improve the cost-effectiveness ratio. Eawag has been studying such scenarios, for instance in the Regional Infrastructure Foresight (RIF) project. From a technological standpoint, both decentralised and centralised measures were investigated for wastewater treatment plants. Analogous to industrial sites that have already erected their own (pre-) treatment plants, the use of decentralised wastewater treatment, e.g. for hospitals or old age and nursing homes, would only be justified if a significant portion of pharmaceutical residues originated from those sources. Eawag is currently performing a pilot project at the Spital von Baden (Baden Clinic) within the scope of the EU Interreg project “Pills”. Other possibilities involving the separate collection and treatment of urine in order to eliminate pharmaceutical residues or the integration of wastewater purification systems in individual buildings are currently being investigated.

• Press release of the Federal Office for the Environment (FOEN) (only in German, French and Italian)
  
• Report by René Gälli, Christoph Ort and Michael Schärer (2009): Micropollutants in water bodies. Appraisal and reduction of pollutions levels in urban drainage systems. [pdf, 3 MB - in German only]

• PILLS Project / Pharmaceutical input and elimination from local sources
  

• Regional Infrastructure Foresight Project RIF