Effects of emulsion viscosity during surfactant‐enhanced soil flushing in porous media

Surfactants can potentially improve the efficiency of pump‐and‐treat technology for remediation of aquifers contaminated by nonaqueous phase liquids (NAPLs). However, the formation of emulsions during the removal process can Increase the viscosity in the system. This can result in pore clogging and reduction of flow, which inhibits the contaminant removal process. Formation of viscous emulsions has been identified in previous research as one of the probable causes for in situ field test failures using surfactant‐enhanced soil‐flushing technology. However, the effects of in situ emulsification and viscosity increases have not been quantified previously. The purpose of this article is to investigate effects of in situ emulsification on the remediation process. Laboratory column studies examined the mobilization of m‐xylene from porous media using a 1% alcohol ethoxylate surfactant solution (Witconol® SN90). Effects of in situ emulsification were determined. Glass columns (1.1 cm i.d. × 30 cm) were packed wi...