One of the interesting facts about the Aare River in Bern, , is that it has good water quality.
This has been confirmed by water samples which resulted in placing the Aare River in the "very good quality" category according to the European Union in 2016. This is a special attraction for the Aare River so that people do not have to worry about accidentally swallowing water while swimming there.
But who would have thought, in the past, the water quality of the Aare River was not as good as it is now. Aare River, once slum. This was revealed by Michael Hengartner, a Swiss-Canadian biochemist and molecular biologist.
"In the past, the water quality in Switzerland was much worse than it is now. Foam floats in many places in the river and there is a bed of algae in the lake," Hengartner was quoted as saying by Sciena.
In his column, Michael Hengartner explains how research has contributed to better water quality and what challenges we face today.
"Water in Switzerland is of high quality. Overseas guests are always amazed that our tap water does not contain chlorine. And they are hard to believe that you can drink well water without any problems and even swim in rivers and lakes," he wrote.
However, continued Hengartner, water conditions in Switzerland are not always like this. Some things may have been better in the past, but Swiss water quality is not. In the mid-1960s, only 14 out of 100 Swiss households were connected to a sewage treatment plant.
In many places, foam floats on Swiss rivers, and the lakes are covered with algae beds that boats have to sweep away. In some areas there is a sign: "Watch out! Polluted water. Do not swallow. Rinse after bathing." Now, things like that are unthinkable because the water is so clean.
In 2017, UNESCO even determined that swimming in the Aare River is on the list of traditions, and is therefore part of Switzerland's intangible cultural heritage. The Swiss Federal Office of Culture decides which activities are classified as "living traditions."
There are various causes of water pollution. Agriculture contributes with too much fertilizer use, as does industry and households. Detergent often gets into unfiltered streams and causes rivers to foam. And in Bern, until the 1980s, household wastewater from the city (including toilets) was only roughly filtered before being discharged into the Aare River.
The fact that so much has been improved for water quality in Switzerland is mainly due to sewage treatment plants. Currently, 97% of households are connected to a sewage treatment plant. The rest live in areas so remote that it makes no sense to link them.
In addition, industrial plants now have better filters and farmers use fertilizers less frequently. Environmental laws are even stricter. For example, the use of phosphates in detergents has been banned.
"Research has also contributed a lot to water quality. In Switzerland, this is especially the case in Eawag. For example, membrane bioreactors, and biofilm reactors have been developed to purify water," said Hengartner.
Measurement methods are also becoming more sophisticated. Currently, for example, residues of antibiotics and other drugs can be measured accurately. Even the Corona virus can be detected in wastewater. But don't worry, this viral residue is no longer contagious.
"Switzerland has achieved a lot in the area of water protection. But new challenges lie ahead. For example, the accumulation of residues in groundwater is a major concern," said Hengartner.
Increasingly frequent heat waves and summer droughts are causing regional water shortages and depressing river and river ecosystems. These problems can no longer be handled selectively, but must be handled holistically.
"So that in the future we can continue to bathe in our lakes and rivers and drink water from our wells, swim leisurely in the Aare, Limmat, or Rhine rivers. These rivers can be used for swimming," he concluded.