Study of the feasibility of in-situ stabilization of PFAS by injection of surface-modified clay

Surface-modified clay has the ability to adsorb PFAS and thus remove them from water. Surface-modified-clay is already used for water treatment and for mixing with soil to reduce PFAS leaching. It has a large adsorption capacity and can also adsorb short-chain PFAS. Moreover, it retains its adsorption properties even at high pH values. However, it is not always practical to mix organoclay with soil. For deeper and hard-to-reach contamination, injection of this clay is a possibility to immobilize PFAS in soil. By adsorbing PFAS to surface-modified, the migration of PFAS into groundwater will be reduced. However, there is currently no experience with injection of this material into soil. This project will investigate whether surface-modified clay can be injected using Injectis’ innovative SPIN® injection technology at 2 sites with different lithology and contamination characteristics. This injection method allows injection substances to be injected homogeneously over a depth interval with different soil layers. In addition, lab tests, batch and column tests, will be performed by VITO to verify the effectiveness and durability of PFAS immobilization in both the short and long term under different stressing conditions. This project will allow to determine under which conditions organoclay can be applied for in situ stabilization of PFAS contamination.