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Experimental and modeling studies of the fate of organic contaminants in the presence of alfalfa plants

Conference ·
OSTI ID:491035
; ; ;  [1];  [2]
  1. Kansas State Univ., Manhattan, KS (United States)
  2. South Dakota State Univ., Brookings, SD (United States). Dept. of Civil Engineering
Experimental investigations were carried out in the laboratory to study the impact of vegetation in bioremediating soil and groundwater contaminated with hazardous organic substances. A 90 cm long chamber with 2 U-shaped channels, each 10 cm in width and 35 cm in depth, was set up. Alfalfa plants were chosen and they have been growing in the channels under laboratory conditions for nearly 2 years. The channels were packed with fine sandy soil collected from near a landfill. The groundwater fed to one channel was water contaminated with toluene solution at saturated concentrations {at} 25 C, whereas, the other channel was fed with water contaminated with phenol solution {at} 500 ppm (v/v). The contaminant concentrations in the groundwater of the channels were monitored at the sampling wells located along each of the channels. The influent and effluent flow rates from each channel were measured every day and recorded. Evapotranspiration significantly influenced the fate of the pollutants. Dispersion and adsorption processes in the channel were studied by introducing bromide tracer, as a broad pulse, into the toluene fed channel and by observing toluene and phenol concentrations, following a feed step change to pure water. Tracer studies indicated that short-circuiting in the end of the channel was quite significant. Models which were previously developed to describe the fate of the contaminants in variably-saturated soils in the presence of vegetation are being employed to simulate the fate of these hazardous organic substances in the laboratory chamber.
OSTI ID:
491035
Report Number(s):
CONF-9406250--
Country of Publication:
United States
Language:
English