IN-SITU SURFACTANT WASHING OF POLYCHLORINATED-BIPHENYLS AND OILS FROM A CONTAMINATED FIELD SITE - PHASE-II PILOT-STUDY

An in situ surfactant washing process was previously developed and successfully pilot-tested at a field site contaminated with polychlorinated biphenyls (PCBs) and oils (Abdul et al., 1992). A second phase of the pilot study, conducted the following year at the same site, confirmed the technical viability of this process. The results of the phase II study surpassed the predictions of the long-term performance of this technology based on the phase I results. Soil cores taken from the plot before the phase I and phase II studies and after the phase II study showed mass reduction and redistribution of the contaminants. A continuous column washing study using the same contaminated soil showed consistency with field results. The amounts of PCBs removed in the laboratory and field studies, respectively, are 7% and 10% after 5.7 pore volume (PV) washings (phase I) acid 19% and 24% after 8 PV washings (phase II). More than 85% of the PCBs were removed from the laboratory soil column after 105 PV washings. This study supports the phase I study which indicates that the in situ surfactant washing process is a viable remediation technology for hydrophobic contaminants.