At Europe’s second largest wastewater treatment plant, Seine Amont, in Valenton, the wastewater of several agglomerations in the Paris area is treated – over half a million cubic meters of wastewater per day, which equals a population of ~ 2,600,000. As one of the measures to make the river Seine swimmable for athletes during the Olympic and Paralympic Games, an additional treatment step was introduced after tertiary treatment to disinfect the effluent from the plant.

Disinfection methods and regulatory compliance

Wastewater can be disinfected using a variety of methodologies, such as UV or chlorine. Efficiency, flexibility, and reliability are key to ensuring pathogen microorganisms such as intestinal enterococci or E. coli are eliminated. At the same time, it is important that regulatory requirements, like the Bathing Water Directive, are met in an environmentally harmless manner.

The D.I. (Direction de Innovation) from the Greater Paris Sanitation Authority had evaluated performic acid over four years with a very comprehensive protocol to prove its efficacy and its zero-environmental impact with advanced analytical methods. Eventually, Kemira’s KemConnect™ DEX solution was selected as it outperformed other alternatives, as outlined in an open-access ebook on the effectiveness of disinfecting wastewater treatment plant discharges using performic acid, published in 2021.

Growing adoption of performic acid disinfection

More and more municipalities like Berlin, Biarritz, and Venice apply performic acid disinfection to their effluent to comply with tight discharge limits. Also, an increasing number of water-intensive industries are opting in favor of Kemira’s technology for water reuse applications.

Performic acid is a powerful peracid compound, produced in equilibrium with formic acid and hydrogen peroxide. The chemical formula is CH₂O₃. It disinfects rapidly and in low doses. The solution is highly efficient even under constantly changing process conditions, without producing any toxic by-products.

Impact on the 2024 Paris Olympic Games

During the 2024 summer season, from April to September, the effluent from the wastewater treatment plant in Valenton near Paris was disinfected reliably before discharge into the river La Seine, helping to meet the required limits according to the bathing water directive for inland waters. For the first time since the Olympic Games in Paris in the year 1900, Olympic and Paralympic athletes were able to compete in seven different events, such as triathlon and marathon swimming in the river again in 2024.