When some are struggling with the Covid-19, at the Saujon thermal baths, the battle of the moment is the legionella! The establishment closes at the end of December for two months. An extended annual closure, the time to carry out work on the thermal water distribution network, in order to get rid of legionella for good.
These potentially deadly bacteria took advantage of the lockdown linked to containment, until May 2021, to make their nests in the pipes. They already had spoiled the start of summer for spa guests, the establishment specializing in mental health having to close its thermal baths for six weeks to fully treat its pipes. But traces of Legionella reappeared in November 2021, which means that we have to use great means.
– Julien Fleury
Legionella detected in the baths
The visit to the thermal baths begins with a small hut. It houses one of the establishment’s two boreholes. “You see a tube that plunges 200m deep, comments Guillaume Mathalan, technical manager of the Saujon thermal baths. There is absolutely no Legionella here, as the water is too cold for them, even though it gets to us at 18 degrees. “
Because it is between 25 and 55 degrees that Legionella can develop. In Saujon, it happens at the end of the chain. “We are monitoring 90 points of our distribution network, and it is especially at the level of the baths that we detected Legionella in November. This is the three main points.” The baths concerned were immediately closed, the time to be decontaminated. Operation then resumed normally.
– Julien Fleury
Create a loop in the hot water circuit
A bad surprise because the establishment thought it had done the hardest this summer. Six weeks of closure, time to cause thermal shocks, by injecting water at very high temperature (70 degrees) into the network. Not to mention regular maintenance. “Legionella likes what is called biofilm, specifies Guillaume Mathalan, a somewhat viscous material found in pipes and which develops on limestone. So we use a descaler, to remove the lime, and then a disinfectant to get rid of the bacteria. “
But that is still not enough. To understand, head for the hydrotherapy baths, fed by water at 55 degrees, but which has tendency to cool at night in the pipes. “And our work will consist in creating a continuous water circuit, a loop, which will create a circulation of water 24 hours a day. The water will no longer stagnate, and will be kept at 55 degrees. Which will prevent development. of the legionella. “
– Julien Fleury
Drastic standards
The solution has been validated by a specialist research firm. A relief for Christine Favre, the health care manager of the spa, on the teeth for six months: “It is a permanent stress, whether it is the Legionella or the enterococci that can be found in swimming pools. As soon as a germ is found, it is in action, we treat everything. Even if it means emptying the pools. swimming pools, and annoy spa guests. “
I have to say that the standards are drastic for hydrotherapy. No germ accepted in the analyzes, when we can go up to 1,000 units of Legionella in the hospital sector. With this work, Olivier Dubois hopes to definitively turn this page of legionella, which blurs the image of his establishment. “It’s not good to have closures. So we’re going to do this work, check that all the results are good, before opening in March. There is no reason why it should not be effective.”
Olivier Dubois who remains marked by the attacks received by the thermal baths of Saujon, after the death of a legionellosis curist in 2019. At the time, however, the analyzes had not detected any bacteria in the establishment.