How can we monitor underground water tables? How can they be protected from various sources of pollution? What warning systems should be put in place? These questions are the subject of a major European research project: NINFA.
Repeated episodes of drought and restrictions on the use of water in certain municipalities seem to quickly be becoming the new normal. The question of the 'health' of groundwater is on the agenda more than ever. A team from IMT Atlantique is working on this issue as part of a major European research project called NINFA.
Launched in November 2022 for a period of 42 months, NINFA1 brings together a dozen players - companies, research centres and academic establishments - from four countries (France, Spain, Italy and the Netherlands), with a total budget of several million euros. The aim is to develop groundwater monitoring strategies, pollution prevention and reduction technologies, and an early warning system.
DSEE Team - part of the GEPEA UMR CNRS 6144 laboratory involved in the NINFA project:
Yves Andrès, coordinator and manager; Sary Awad, Claire Gérente and Valérie Héquet, research professors; and Henrietta Whyte, R&D Engineer.
Groundwater faces a number of threats. "It is subject to various forms of pollution, in particular contamination by surface water or urban run-off during storms," explains Yves Andres, head of the Energy Systems and Environment Department (DSEE / GEPEA), and coordinator of the project for IMT Atlantique. "It can be contaminated by pesticides, pharmaceutical products (antibiotics in particular), micro-plastics, etc. It also contains heavy metals and hydrocarbons. Water tables are also affected by over-consumption, linked in particular to the high temperatures caused by climate change." Added to this is the phenomenon of the "salt wedge" along the coast: brackish water can penetrate and push back the fresh water in coastal aquifers.
Case studies in six countries
Hence the need to devise ways of monitoring water quality and combating pollution, as inexpensively as possible. This is the approach taken by NINFA, which aims to propose "innovative technological solutions" and to lay the foundations for a more efficient groundwater management system, including the reuse of treated wastewater.
Spearheaded by LEITAT, a Spanish multi-technology research center, the project is based on several in situ case studies: two in France, two in the Netherlands, three in Spain, and three more in Egypt, Colombia and Mexico.
The first stage will involve examining the scientific literature and selecting various processes, then developing solutions in the laboratory, before moving on to full-scale deployment in the field.
More specifically, the IMT Atlantique team is responsible for coordinating the presentation of the case studies and establishing a working framework. The team will have to assemble the specifications for the case studies, collect and compile the data collected in the field, propose a monitoring methodology with key indicators, and think about solutions and models. The researchers will have to answer a number of questions: Which treatment process should be chosen? What measurement strategy should be used? What indicator should be used for pharmaceutical residues, for example? How can a particular process be validated? And there is a risk that some pollutants might slip through the net.
DSEE/GEPEA researchers are also working on other issues, such as the elimination of certain specific pollutants and how to optimize this elimination on a laboratory scale.
Combining several treatment processes
"Generally speaking, the most promising approach today is to combine different processes," emphasizes Yves Andrès. "For example, activated carbon can be used in conjunction with advanced oxidation and slow filtration to treat effluent from wastewater treatment plants. But how do you combine these three processes? In what order should they be used? For each operation, we need to choose the most effective one, depending on the pollutants we want to treat." In addition, the effects of run-off will be 'treated' before infiltration.
"NINFA is based on a highly multidisciplinary approach, leading to a systemic vision of the subject," continues the researcher. The project calls on digital technology (particularly for modeling groundwater), chemistry, physics and biology (for the processes implemented). The project also includes a section dedicated to the human and social sciences (SHS), with the reuse of wastewater and its acceptance by the population.
Another advantage of the project is its strong international dimension, which will make it possible to tackle a wide range of groundwater-related issues linked to local situations. Another benefit is the possibility of gaining insight into how these issues are dealt with in different countries. "In technological terms, France is not lagging behind in this area," says Yves Andres. "But we do have a problem with the implementation of appropriate measures, particularly when it comes to the reuse of treated wastewater. Other countries such as Spain and the Netherlands, for historical or geographical reasons, are more aware of the need to reuse wastewater or to monitor and protect their groundwater". For the time being, the project is still in its very early stages: the first protocols will not be deployed before this summer or early autumn by the various partners.
(1) TakiNg actIoN to prevent and mitigate pollution oF groundwAter bodies.
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by Pierre-Hervé VAILLANT