Early in the morning of Tuesday, July 17th, the second application of hydrogen peroxide was made by the company Arcadis equipped with a light equipment on zodiac better adapted to the surface of the zone to be treated. Once again, teams from the Grand Bassin de l'Oust and the University of Rennes 1 were present to supervise the experiment, while cyanobacteria were more visible in the water than the previous application.
The academics were able to observe the modified conditions of the site, since the water level had dropped significantly, thus decreasing the volume of water to be treated and the height of the water column. The amounts of hydrogen peroxide have therefore been estimated accordingly. Preliminary analyzes have also been done in the bathing area and outside to find out the cyanobacteria concentrations, the temperature of the water, etc.
Arcadis has been spreading on the zodiac, a new tool for this type of treatment in smaller areas and thus more suitable for treatment in the Lac au Duc bathing area. The researchers continued their analyzes, especially outside the zone, to verify the losses of H2O2 and the impact on the ecosystem.