| The overall objective of this research is to systematically understand and evaluate basic causes and possible solutions to the soil clogging phenomena associated with surfactant enhanced remediation. This will involve a study of each of the five possible causes of the clogging phenomena (surfactant adsorption, precipitation, micelle size, dispersion, and soil fabric). After studying each of the possible mechanisms in batch mode, the most prevalent processes will be employed to explain the clogging behavior through the use of hydraulic conductivity testing in flexible wall permeameters.; Surfactant adsorption and precipitation will be studied through batch testing. Micelle size will be quantified through the use of both Atomic Force Microscopy (AFM), and Dynamic Light Scattering (DLS) testing. Dispersion tests will be carried out utilizing basic hydrometer analysis, as outlined in ASTM D 4221 Standard Test Method for Dispersive Characteristics of Clay Soil by Double Hydrometer. The determination of soil fabric will be characterized using Scanning Electron Microscope (SEM) techniques.; In order to determine the hydraulic conductivity of the study soil using various solutions and soil fabrics, ASTM D 5084 Standard Test Method for the Measurement for Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter will be followed. This research will focus on using trichloroethylene (TCE) as a representative contaminant, and utilizing a glacial till soil containing a high percentage of fines, as the study soil. The soil clogging phenomena will be examined while varying three testing parameters. These will be surfactant concentration, electrolyte concentration, and contaminant concentration. The surfactant selected for study is the anionic MA 80-I. The electrolyte used will be sodium chloride (NaCl), and the chosen contaminant will be TCE.; The results of this research will provide a better understanding of the causes of soil clogging during surfactant injection, and possible techniques to develop optimum surfactant formulation to provide efficient contaminant removal. |
