Recovery of coal tar in 1-D column test using surfactant enhanced aquifer remediation (SEAR)

Abstract

This paper presents the results of flow-through column testing using a new surfactant, Alfo–terra 123-8 PO sulfate, for the recovery of coal–tar from contaminated soil. Coal tar is a dense, non–aqueous phase liquid (DNAPL) that is difficult to recover due to its hydrophobic behavior and its high viscosity. Preliminary testing (phase behavior–batch tests) revealed a high degree of coal tar solubilization using a formulation of 12 wt.’%o Alfo–terra 123-8 PO sulfate surfactant, 4 wt.Yo secondary butanol, and 200 mg/L calcium chloride (as calcium). The formulation also exhibited rapid equilibration, without forming anisotropic gels. The column test was performed to verify compatibility of the formulation with the field-obtained DNAPL and soil, The column test was successful, resulting in low pressure drop, over 97 0/0 coal tar recovery, with no visible gel formation nor any coal tar mobilized. This experiment showed good compatibility of the selected surfactant using field soil and field DNAPL, and should be studied fiu-ther and considered for use in the field.