Phase Diagrams to Optimize Surfactant Solutions for Oil and DNAPL Recovery in Aquifers

Abstract

AbstractPhase diagrams can be used to optimize the composition of surfactant solutions (cosurfactant/surfactant) designed for the recovery of DNAPLs at residual saturation in aquifer formations. The study also shows that the combination of cosurfactant (alcohol) and surfactant is more effective than the use of alcohols or surfactants separately. The suggested approach is based on miscible oil displacement using surfactant solutions at high concentrations. Most of the recent projects using surfactants for aquifer cleanup use low‐concentration solutions that promote immiscible oil displacement. The goal of the present study is to demonstrate the potential of optimized surfactant solutions to restore oil and DNAPL‐contaminated sites such as the one in Ville Mercier, Quebec (site contaminated with a mixture of petroleum and chlorinated solvents). The results show that alcohol/surfactant systems can be used to solubilize chlorinated solvents (TCE, PCE) and light oils (gasoline, diesel). For the dissolution of heavy and viscous oils (motor oil, ATF, creosote, Ville Mercier oil), an organic solvent must be added to the alcohol/surfactant system.