Foam placement for soil remediation

Abstract

Environmental contextSoil pollution is an important concern and remediation techniques, especially in situ techniques, should be studied. We investigate a new technique based on foam generation and placement inside the porous soil to improve the pollutant extraction. This technique could be useful when the soils are heterogeneous because it allows a complete soil sweeping. AbstractFoam can be generated in porous media, mainly by snap-off phenomena, by co-injecting gas and a surfactant solution. The liquid films that separate the gas bubbles, called lamellae, and gas trapping in small pores where capillary pressure is high generate a resistance to flow that drastically decreases fluid mobilities in porous media. Experiments performed with a 2D laboratory pilot consisting of two layers with different properties clearly highlight that foam is generated in the high-permeability layer and will divert flow towards the low-permeability region. This behaviour is of great interest for the remediation of heterogeneous polluted soils.