At the BRGM Test Facility in France, PHISHES is advancing research on PFAS contaminated soil through controlled experiments and modelling approaches focused on contaminant transport, remediation technologies and soil functions.
The BRGM Test Facility, known as the PRIME platform, supports experiments under controlled conditions ranging from laboratory to semi-real scale. The facility helps researchers investigate pollutant migration from soil to groundwater while also testing remediation and mitigation technologies.
Several remediation technologies have previously been tested at the BRGM facility, including in situ flushing using non-Newtonian fluids (NNF). Within PHISHES, particular attention is being given to this technology because of its relevance for the collaborative work between BRGM and the Swedish Geotechnical Institute (SGI) linked to the Örnsköldsvik Airport test site in Sweden.
From controlled conditions-experiments to integrated modellingFrom controlled experiments to integrated modelling
Previous long-term experiments conducted on a plurimetric platform (Figure 1) within the PROMISCES project generated datasets on PFAS migration, groundwater recharge, water flow, and contaminant transport under controlled conditions. These experiments also provided proof of concept for remediation technologies, including in situ flushing using NNF.
Figure 1: Schematic sketch of the plurimetric pilot.
Building on this existing knowledge and previous results, the PHISHES project is developing new experiments under both static (batch) and dynamic conditions (1D columns and 2D tanks) to assess the impacts of in situ flushing using Non-Newtonian Fluids (NNF) on the following soil functions: water retention, infiltration and recharge and pollutant transfer and buffering, and, to a lesser extent, carbon cycling and microbial diversity. The data generated from these experiments will be used to feed the modelling chain combining 1D-Hydrus, MODFLOW, MT3DMS and PHREEQC, which is being developed to simulate soil functions in PFAS-contaminated soils (Figure 2).
Figure 2: Sketch of the model train developed to simulate the main soil functions in PFAS contaminated soils.
Next steps: planned activities within PHISHES Next steps: planned activities within PHISHES
Although no new experimental activities have yet been carried out since the start of the project, the design of the upcoming experiments at the BRGM Test Facility has been finalized.
Planned activities include the first 1D column experiments and 2D tank experiment, together with the development of an initial version of the modelling chain capable of simulating the impacts of in situ flushing using NNF on soil water retention and infiltration, as well as pollutant transfer and buffering. Soil samples will also be preserved for future analyses aimed at assessing impacts on carbon cycling and microbial diversity.
Future work will also support the use of datasets obtained under controlled laboratory conditions to parameterize models simulating the impacts of in situ flushing using NNF on soil functions at the Örnsköldsvik Airport test site in Sweden.