Mobility and relative permeability effects on surfactant-enhanced remediation treatments

In order to study the influence of mobility and relative permeability effects on surfactant-enhanced remediation processes, carefully-designed porous media experiments have been conducted with trichloroethylene (TCE) as the contaminating phase in sandpacks prepared with Ottawa sand. Injection of an aqueous solution of the anionic surfactant MA-80 into linear sandpacks resulted in the removal of >99% of the residual TCE within 2 pore volumes. Multiple pressure taps along the sandpacks revealed a high pressure transient associated with the movement of the NAPL bank through the column; this is attributed to a relative permeability effect localised at the front of the NAPL bank. Experimental evidence for the formation of viscous NAPL/surfactant phases both within and outside the sandpacks were also obtained. The impact of these mobility and relative permeability effects on SEAR process efficiency was simulated by conducting parallel sandpack floods with one sandpack initially at residual TCE concentration and the other free of TCE. In the higher-dimensional parallel flood, in fact, these factors cause the majority of the surfactant solution injected to enter the clean column. Classificato ISI