THE ROLE OF FIELD TRIALS IN DEVELOPMENT AND FEASIBILITY ASSESSMENT OFSURFACTANT-ENHANCED AQUIFER REMEDIATION

The development of surfactants for aquifer remediation involved simult aneous research at laboratory and field scale to expedite technology d evelopment. The results of field trials provided direction for laborat ory research by identifying the critical parameters that limit perform ance while the results of laboratory research helped design and interp ret the field trials. The combined field and laboratory work has ident ified the factors to be considered in a feasibility assessment of surf actant-enhanced remediation. The principal requirements are adequate h ydraulic conductivity (>10(-6) m/s), the ability to attain hydraulic c ontrol and ability to control downward dissolved nonaqueous phase liqu id migration. Field trials have demonstrated that surfactants can rapi dly remove mass; however, because heterogeneities cause tailing in con tamination removal, restoration to drinking water standards may not be achieved. Optimization of surfactant solution composition can increas e the rate of mass removal and hence minimize cost. The fraction of ma ss removal, the level of contamination remaining and the cost of remed iation using surfactants are all dependent upon a site's hydrogeology. Thus both minimization of cost and maximization of nonaqueous phase l iquid removal requires detailed site characterization as well as optim ization of surfactant solution composition. Field trials provide an es sential component both in technology development and derailed feasibil ity studies.