AbstractMicellar‐enhanced ultrafiltration (MELT) and air stripping were evaluated for surfactant‐contaminant separation and surfactant recovery. Two linear alkyl diphenyloxide disulfonate (DPDS) surfactants were evaluated with the contaminants naphthalene and trichloroethylene. A separation model developed from micellar partitioning principles showed a good correlation to batch MEUF studies, whereas flux analysis highlighted concentration polarization effects in relation to hydrophobe length. MEUF effectively concentrated the surfactant‐contaminant system (93 to 99 percent retention); however, this did not result in surfactant‐contaminant separation. Batch and continuous flow air stripping models were developed based upon air/water ratio, surfactant concentration, and Micellar partitioning; model predictions were validated by experimental data. Sensitivity analyses illustrated the decline in contaminant‐surfactant separation with increasing surfactant concentration (e.g., TCE removal efficiency declines from 83 percent to 37 percent as C‐16 DPDS concentration increases from 0 to 55 mM). This effect is greater for more hydrophobic contaminants (naphthalene vs. TCE) and surfactants with greater solubilization potential (C16‐DPDS vs. C‐12 DPDS). The resulting design equations can account for this effect and thus properly size air strippers to achieve the desired removal efficiency in the presence of surfactant micelles. Proper selection and design of surfactant‐contaminant separation and surfactant recovery systems are integral to optimizing surfactant‐enhanced sub
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