“Today in France, less than 1% of the water comes from the reuse of wastewater, while this is common in Italy (8%) and Spain (14%). We need to raise awareness of the need for reuse, to preserve water resources”, argues Frédéric Salin, head of Veolia water in the Aude department.
The “reut”, according to the jargon of water experts, is frequent in countries where water is scarce, and which have no other choice, such as Israel, Singapore or Namibia.
In the Narbonne wastewater treatment plant, as in five others in France, the operator Veolia commissioned a “Réut Box” in 2021, an infrastructure held in a container which provides an additional stage in the treatment of water from sewers.
Rather than discharging it into rivers or the sea, this technology, with a treatment capacity of up to 75 m3/h, makes the water clean enough to be used in agricultural irrigation, urban cleaning, watering of green spaces, stadiums or golf courses.
– Industrialize –
“We must industrialize the ‘réut’. We will install this device wherever possible. By the end of 2023, we are counting on the commissioning of one hundred ‘Réut box’, a pioneering approach that will save 3 million m3 of drinking water, the equivalent of the annual consumption of a city of 180,000 inhabitants”, calculates François Reboul Salze, innovation manager at Veolia.
Near Narbonne, vines are watered thanks to the reuse of dirty water from another wastewater treatment plant.
“It’s the future, we have a crucial need to save drinking water and help winegrowers. Now we are thinking about a distribution network for agricultural irrigation, but it is expensive”, regrets Michel Jammes , vice-president of the Greater Narbonne intercommunality, in charge of water.
The 7 km of pipeline irrigating 80 hectares of vines cost around 750,000 euros. This system, he points out, allows winegrowers to free themselves from pumping and watering restrictions.
To plead the cause of the reuse of wastewater, François Reboul Salze highlights that “many of the tomatoes from Spain that we consume have been irrigated thanks to ‘réut’ (reused water, in the jargon of water treatment). water)”.
If France was slow to activate this technology, estimates Sophie Besnault, expert in water treatment from INRAE (the national research institute for agriculture, food and the environment), it is because ‘we “didn’t necessarily need it, when we don’t have a lack of water… And because of regulatory constraints, the specifications are complex, it’s expensive”.
– Water emergency –
“It’s a solution for the future to save drinking water, but it won’t solve all our problems, points out Sophie Besnault. You have to be quite careful, it’s water that is no longer poured into the nature, it is necessary to study the possible impact on the watercourse”.
The intensity and frequency of drought episodes are likely to increase further around the Mediterranean, predicts the Intergovernmental Panel on Climate (IPCC).
For Tatiana Vallaeys, expert at the Rhône-Mediterranean Basin Agency, “the question of water is more urgent than that of energy”.
“We must anticipate the drop in flow of the rivers, we predict a drop of 50% to 80% in the flow of the Rhône by 2100, she underlines. (…) How are we going to cool the power stations? nuclear weapons? The alarm signal has been sounded”.
“We are already faced with conflicts of water use, when we see water transport by truck, we have a problem, and we are only at the beginning of the problems”, assures the scientist.
In recent years, the consumption of dirty water has been popularized by Thomas Pesquet and the astronauts of the international space station, “where 100% of wastewater is recycled”, notes the professor from the University of Montpellier.