Laboratory Investigation of Surfactant-Enhanced Trichloroethene Solubilization Using Single-Well, 'Push-Pull' Tests

Autor: Thomas E. Sawyer, Martin H. Schroth, Jennifer A. Field, J. D. Istok, M. D. Humphrey
Rok vydání: 1999
Předmět:
Zdroj: Ground Water. 37:581-588
ISSN: 1745-6584
0017-467X
Popis: The objective of this study was to evaluate the ability of the single-well, "push-pull" test to characterize the enhanced solubilization of trichloroethene (TCE) by a hexadecyl diphenyl oxide disulfonate (DOWFAX) surfactant. Batch solubilization experiments indicated a linear relationship between TCE solubility and DOWFAX concentration characterized by weight- and molar-solubilization ratios of 0.26 and 1.25, respectively. Laboratory push-pull tests were performed in wedge-shaped physical aquifer models to simulate the alternating radially divergent/convergent flow field in the vicinity of an injection/extraction well. Experiments were conducted in a TCE-free sediment pack and in a sediment pack initially containing liquid TCE with an initial saturation of approximately 5% of the total pore volume. In an experiment conducted in the absence of DOWFAX, maximum TCE concentrations during the extraction phase were approximately 0.6 g/L. In contrast, in an experiment conducted with 13.5 g/L active DOWFAX, TCE concentrations during the extraction phase increased to approximately 3.2 g/L and TCE mass recovery increased by a factor of approximately 3. Two additional experiments conducted with DOWFAX in the same sediment pack yielded smaller maximum TCE concentrations and mass recoveries. The increased density of injected DOWFAX solutions due to TCE solubilization resulted in significant sinking of injected solutions and an accumulation of DOWFAX and TCE at greater depths in the sediment pack; however, no mobilization or sinking of liquid TCE was observed. The results indicate that push-pull tests can provide useful information on surfactant enhanced solubilization of nonaqueous phase liquids in the subsurface.
Databáze: OpenAIRE
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