From a strong sewer system to underground tank: How did Paris make its billion-dollar Seine River cleanup a sucess?

Seine was opened for public swimming on July 5, Saturday

On Saturday, Paris opened the Seine River back for the public for swimming purposes for the first time since 1923. This was made possible after a billion-dollar cleanup project that the authorities undertook after the city won the bid for hosting the 2024 Olympics in 2016. The river was then open for certain swimming competitions.

However, the Seine was not always ready for swimming and for regular public use. For over a century, Seine had a “poop problem” as untreated sewage frequently entered the river, thus making it a breeding ground for E Coli.

The river's water was toxic for many fish breeds and public swimming had been banned in the river since 1923. However, now that problem has been solved, with the river opening for public swimming once again on July 5, Saturday.

Paris reportedly spent billions of dollars to fix the Seine and to improve the quality of water, making it fit for public use once again. One thing that helped Paris authorities to clean the Seine river is the creation of a giant underground rainwater storage tank in southeastern Paris.

The tank capable of holding enough water to fill up 20 Olympic-size swimming pools. Moreover, it is meant to hold most runoff water during heavy rains, and prevent overwhelming the city’s sewege systems. In addition to that, the city has also made major investments to make links with thousands of homes and connect them to the sewer system and to improve the water treatment facilities to make them efficient.

Authorities in Pris have also said that daily water quality tests will be conducted during the swimming season at designated swimming areas to make sure that the water quality in the Seine river remain fit for public use.