That's why our water is so clean

I grew up in Canada. It's nice and cool there even in summer. Here in Switzerland, on the other hand, summers are really hot. What to do? Some seek cool air in the mountains, others jump into cool water.

Our Swiss water   has high quality. Guests from abroad are always amazed that our tap water contains no chlorine. And they find it simply unbelievable that you can drink well water without any problems and even swim in rivers and lakes.

But it was not always like this. Some things may have been better in the past, but  Swiss water quality was definitely not! In the mid-1960s, only 14 out of 100 Swiss households were connected to a sewage treatment plant. In many places, foam floated on Swiss rivers, and the lakes were covered with carpets of algae that had to be "grazed" by ships (popularly known as "manatees"). At the lido of Solothurn there was a sign saying: "Caution! Water polluted. Do not swallow. Rinse off after bathing." Today that would be unthinkable.

The causes of water pollution were manifold. Agriculture contributed with too much fertilizer, industry as well, but also households. Detergents often entered watercourses unfiltered and caused foaming brooks. And in Berne, until the 1980s, household wastewater from the old town (including toilets) was only roughly filtered before being discharged into the Aare.

The fact that so much has improved for Swiss water is mainly due to the sewage treatment plants. Today, 97 percent of households are connected to a sewage treatment plant. The rest lives in areas so remote that it makes no sense to connect them. In addition, industrial plants now have better filters and farmers are more reluctant to use fertiliser. And the laws have become stricter: For example, phosphates in detergents have been banned.

Research has also contributed a lot to water quality. In Switzerland, this takes place mainly at Eawag. For example, membrane bioreactors, fluidised bed processes and biofilm reactors have been developed to purify the water in the WWTPs. The measuring methods are also becoming increasingly sophisticated. Today, for example, residues of antibiotics and other drugs can be measured accurately. Even the coronavirus can be detected in the waste water! (But do not worry, these virus residues are no longer contagious).

Switzerland has achieved a great deal in the area of water protection. But new challenges lie ahead. For example, the accumulation of residues in groundwater is a major concern. Increasingly frequent heat waves and summer droughts are leading to regional water shortages and stressing the ecosystems of streams and rivers. These problems can no longer be tackled selectively, but must be tackled holistically. So that we can in the future continue to bathe in our lakes and rivers and drink the water from our wells. Today, the weather should be very nice. Have a  carefree swim in the Aare, Limmat or Rhine. They are all "bathable".

The article originally appeared in SonntagsBlick.