Surfactant-Enhanced Remediation of a Trichloroethene-Contaminated Aquifer. 2. Transport of TCE

Abstract

Field studies were conducted under an induced gradient in a trichloroethene (TCE)-contaminated aquifer at Picatinny Arsenal, NJ, to study (a) the rate-limited desorption of TCE from aquifer sediments to water and (b) the effect of a surfactant (Triton X-100) on the desorption and transport of TCE. Clean water was injected into the contaminated aquifer for 206 day. Triton X-100 was added for a 36-day period (days 36-71 from the start of clean water injection). The effect of Triton X-100 on the desorption and transport of TCE in the field was examined by observing the concentrations of these two solutes in four monitoring wells 3-9 m from the injection wells. These data show a small but discernible increase in the TCE concentration in two of the wells corresponding approximately to the time when surfactant reaches the wells; in the other two monitoring wells, the increase in TCE concentration is negligible. A solute transport model that assumes local sorption equilibrium and used a laboratory-derived distribution coefficient could not adequately describe TCE desorption and transport observed in the aquifer. Two model formulations that accounted for rate-limited sorptionstwosite and multisite modelssfit the data well. TCE concentrations after surfactant injection were underpredicted by the models unless mass transfer rate was increased to account for the effect of surfactant on the rate of TCE desorption. The concentration data from the two wells and the model analysis suggest that the rate of TCE desorption is increased (by approximately 30%) as a result of Triton X-100 injection.

Influence of a Nonionic Surfactant (Triton X-100) on Contaminant Distribution between Water and Several Soil Solids

“…Although this condition can be met by applying very large quantities of surfactant to the system (i.e., X CMC) (13,14), it is desirable to explore conditions for effective soil/solid remediation by use of reduced surfactant loads. In studies of contaminant desorption from soil, it has been shown that low to moderate levels of some surfactants can significantly increase the rate of desorption by increasing the mass-transfer coefficients of contaminants (14,15,(20)(21)(22). In such studies, it is equally important to elucidate the effect of the added surfactant on the contaminant distribution coefficient between soil and water as it would also affect the rate of desorption by changing the contaminant concentration gradient.…”

Surfactants enhanced recovery of endosulfan from contaminated soils

“…The addition of surfactants enhanced the recovery, possibly by reducing the tortuosity of the soil organic matter (Sahoo et al, 1998). Decrease in tortuosity might be due to two mechanisms.…”

The sorption characteristics of PAHs onto soils in the presence of synthetic and bio surfactant

“…During the sorptiondesorption process, there are mainly three reactions occurring such as: (1) the dissolution of PAHs in the micelle phase, (2) the sorption of surfactant in the soil phase, (3) the partition of PAHs between aqueous and soil phase [7]. As all of three reactions reach equilibrium, the partition coefficient is defined as the ratio between the concentration of the PAHs in the soil phase and in the liquid phase (water+micelle), respectively.…”