The effect of physical heterogeneity on transport of gas-phase contamination in unsaturated structured porous media
- Univ. of Arizona, Tucson, AZ (United States)
The efficacy and rate of removal of volatile organic compounds from the vadose zone by soil venting tends to decrease with time of remediation. This decreasing efficiency is attributed to, among several factors, the physical (structured porous media) and chemical heterogeneity of porous media. We performed a laboratory column study to investigate the constraints of macroporous media on transport and removal of conservative (methane) and reactive (TCE, benzene, toluene) tracers. Dry glass beads and artificial macropores were used to simulate a structured porous medium. We quantified the contribution of axial diffusion, hydrodynamic dispersion and diffusion between macro- and microporous domains to the total dispersion of contaminant for gas velocities ranging from 6 to 200 cm/min. We found that axial diffusion and hydrodynamic dispersion were predominant components of total contaminant dispersion at gas velocities lower than 20 cm/min and between 40 to 110 cm/min, respectively. Mass transfer between macro- and microporous domains was the major contribution to total dispersion at gas velocities greater than 120 cm/min. The transport of TCE, benzene, and toluene was quantified and evaluated for the effect and contribution of physical vs. chemical processes to nonideal transport and removal.
- OSTI ID:
- 126383
- Report Number(s):
- CONF-950402-; TRN: 95:006086-0367
- Resource Relation:
- Conference: 209. American Chemical Society (ACS) national meeting, Anaheim, CA (United States), 2-6 Apr 1995; Other Information: PBD: 1995; Related Information: Is Part Of 209th ACS national meeting; PB: 2088 p.
- Country of Publication:
- United States
- Language:
- English
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