Giving wastewater a second life

Last March, Emmanuel Macron presented a vast plan of some fifty measures to organize the sober use of water. In the global context of global warming, droughts are set to multiply and intensify, depriving France of a significant portion of this essential resource. The effects of this water stress are already being felt: in the summer of 2022, for example, restrictions on agricultural irrigation led to yield reductions estimated at between 10% and 40%.

Jennifer Gallé, The Conversation FranceElsa Couderc, The Conversation France and Julie Mendret, University of Montpellier

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One of these measures concerns the reuse of treated wastewater, or REUT. France is a relative novice in this field, with less than 1% of water used coming from this process. In Europe, Spain and Italy lead the way with 14% and 8% REUT respectively. The spring 2023 water plan proposes to increase France's share to 10% by 2030. An "ambitious objective", stresses Julie Mendret, PhD in environmental process engineering and lecturer at the University of Montpellier, guest on the new episode of the "L'échappée Sciences" podcast.

What are the reasons for France's delay? What are the stages involved in the transition from wastewater treatment plant to LWR? What do we do with this treated wastewater? These are just some of the questions to which Julie Mendret provides valuable answers.

In this new episode of "L'échappée Sciences", we look at how trees harvest water from the soil and distribute it to all floors to ensure hydration. Researchers and engineers draw inspiration from these regulation strategies to develop filtration and desalination membranes.

We also learn that much of the water pumped by trees is returned to the atmosphere through evapotranspiration. This "green" water is essential to the water cycle, but is still relatively little-known, and is now a key area of study for hydrogeologists.

Animation and design, Jennifer Gallé and Elsa Couderc. Director, Romain Pollet. Theme music: "Chill Trap" by Aries Beats. Extracts: TF1 TV report, June 26, 2023, D. Sitbon, A. Cazabonne, A. Delabre; "The Trees They Do Grow High", Joan Baez/1961/UMG (on behalf of EMI).

Jennifer Gallé, Environment + Energy Editor, The Conversation FranceElsa Couderc, Science + Technology Editor, The Conversation France and Julie Mendret, Associate Professor, HDR, University of Montpellier

This article is republished from The Conversation under a Creative Commons license. Read theoriginal article.