Connection rate to wastewater treatment plants
Wastewater treatment plants (WWTP) treat the wastewater from industry, commerce and households so efficiently that the treated water can be discharged into natural surface waters. Although not all the toxic substances can be completely eliminated, a good technical performance level in the plants can considerably reduce the introduction of pollutants into the waters. This approach has improved the quality of Swiss surface waters significantly over the last 50 years.
In 1965 only 14% of the Swiss population was connected to a central treatment plant, but this figure reached 97% in 2005. A further 1% of the population could possibly be connected. Connection is not appropriate for the remaining 2% because they live in remote regions with low population densities. The potential is now 100% utilised.
At present the challenges are to establish sustainable wastewater treatment and keep improving the treatment system. The technical performance level of the WWTP has improved continuously over the last 30 years and is now of a good standard, but the treatment of micropollutants needs to be improved regionally. By installing an additional purification stage, the treatment performance could be doubled to reduce the input of micropollutants into the watercourses significantly.
On 3rd march 2014, National Council and Council of States agreed to the proposal of the Federal Council to finance at a national level the upgrading of about 100 wastewater treatment facilities to eliminate micropollutants. Therefore, the Water Protection Act was adopted in order to introduce a nationwide wastewater levy (limited until 2040), according to the polluter pays principle.The relevant legal regulations entered into force on 1 January 2016.
The rate of connection to central wastewater treatment plants (WTP) is often used as a measurement parameter to describe a country's water protection measures. The data are forwarded to the OECD. With almost total utilisation of the potential at 97%, Switzerland’s connection rate to wastewater treatment plants is very good, having one of the highest percentages in Europe. The plant upgrade level is also of a good standard in international terms. By selectively upgrading its WTPs to eliminate micropollutants, Switzerland is taking on a pioneering role.
By regular surveying of the cantonal departments information is collected on the connection rate, operation and maintenance, maintained value and success monitoring of municipal wastewater disposal. The VSA (Swiss Water and Pollution Control Association) also collects data regularly on wastewater disposal costs and performance.
|Targeted trend||Initial value||Final value||Variation in %||Observed trend||Assessment|
|Stabilisation*||Average 2000-2002||Average 2015-2017||1.67%||Stabilisation||positive|
*Since 2005 the connection potential has been 100% achieved, which is why a stabilisation is considered positive.