Depollution: new research and innovation platforms at the BRGM

In France, over 7,200 sites are polluted with heavy metals: lead, copper, chrome, hydrocarbons, or organochlorine compounds, such as pesticides or solvents. Managing the sites and the polluted soil is a major environmental issue, but it is also a health and economic issue. The PRIME initiative, which is part of the PIVOTS programme, aims to identify and quantify pollutants in soil and underground water, to predict their impact on our environment, and to create solutions for remediation. What makes PRIME unique is that it works on multiple scales, enabling a global approach, closely linking lab and field, and enriching experimentation with modelling. The submetric columns, ranging from 20 cm to 1 metre, are used in the lab to carefully study the physical, biological and chemical changes in pollutants. The data gathered at this scale are used to interpret more complex observations carried out via vaster systems. The metric columns provide a smaller scale and controlled model of a polluted zone from the surface soil down to the groundwater. They allow us to characterize the exchanges between environments, such as the root systems and the groundwater, in great depth. The Labbio system enables us to study the migration of and changes to pollutants from soil to underground water as a function of surface conditions. The Trinappe system allows us to study the interaction between the different zones of groundwater. In this unit, water circulates from surface to the depths, but it can also rise to simulate a water-table rise. This innovative system is a unique tool for gathering data on phenomena that are difficult to study in real life. These different systems have sensors which measure flows of pollutants that have been stabilized, transformed or washed. These are ideal places for developing new quantification technology. The multi-metric system was designed to reproduce polluted sites or soil under controlled conditions and at a scale similar to that of the real world. It is thus an ideal system for developing diagnostic tools and remediation techniques. This tool can also verify digital models. This unit is a vast experimental reservoir. It is about 150 m3 in volume and has double walls to regulate the reservoir's temperature. The hood above the reservoir allows for experimentation with plants and helps control potential flows of volatile pollutants. The reservoir's walls feature holes that can be fitted with sensors and provide access to various depths inside the reservoir, all along the unit. The system's configuration allows the reservoir to be split into up to 4 modules filled with different materials, water, sand, polluted or unpolluted soil, mining residues, sediments, etc., in order to conduct simultaneous experiments. These modules are formed by walls and dividers made of alloy, which resists corrosive pollutants, or of polypropylene, which can be used with electrical geophysical methods. The modularity and unique traits of the unit make it a one-of-a-kind system in Europe. As well as these systems, the PRIME initiative brings together expert teams from BRGM, who are ready to work with public and private partners on innovation and development, from design to execution and promotion, in the Centre region, in France and abroad, in order to better understand and preserve our environment.