Water-to-Air Mass Transfer of VOCs: Laboratory-Scale Air Sparging System
Publication: Journal of Environmental Engineering
Volume 124, Issue 11
Abstract
Nonequilibrium air-water mass transfer experiments for six volatile organic compounds (VOCs) were conducted using a bench-scale air sparging system. VOCs used were carbon tetrachloride, trichloroethylene, tetrachloroethylene, chloroform, dichloromethane, and toluene. The average particle size of the porous media used ranged from 0.278 to 1.71 mm. The air-water mass transfer coefficients were estimated by fitting the experimental data to a lumped parameter model. The model assumed that the saturated porous media under air sparging conditions consisted of two zones. In the “mass transfer” zone, VOCs were directly impacted by the flow of air in the air channels, while in the “bulk water” zone, VOCs were not directly affected by the air flow in the air channels. The estimated air-water mass transfer coefficients (KGa) were found to increase for higher injected air flow rates and for larger mean particle sizes of porous media but were inversely proportional to the Henry's law constant of the VOCs. An empirical correlation was developed by correlating the Sherwood number with the Péclet number, the Henry's law constant, and the mean particle size of porous media. The estimated fraction (F) of the total volume of the porous media directly affected by air channels was between 5 and 20% for fine sand, indicating that a small fraction of the porous media was affected by the advecting air stream.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Ahlfeld, D. P., Dahmani, A., and Ji, W.(1994). “A conceptual model of field behavior of air sparging and its implications for applications.”Ground Water Monitoring and Remediation, 14(4), 132–139.
2.
Allison, L. E.(1960). “Wet-combustion apparatus and procedure for organic and inorganic carbon in soil.”Soil Sci. Soc. Am. Proc., 24(1), 36–40.
3.
Armstrong, J. E., Frind, E. O., and McClelland, R. D.(1994). “Nonequilibrium mass transfer between the vapor, aqueous, and solid phases in unsaturated soils during vapor extraction.”Water Resour. Res., 30(2), 355–368.
4.
Cho, H. J., and Jaffe, P. R.(1990). “The volatilization of organic compounds in unsaturated porous media during infiltration.”J. Contaminant Hydro., 6(4), 387–410.
5.
Hein, G. L., Hutzler, N. J., and Gierke, J. S. (1994). “Quantification of the mechanisms controlling the removal rate of volatile contaminants by air sparging.”Proc., 1994 Nat. Conf. on Envir. Engrg., J. N. Ryan and M. Edwards, eds., ASCE, New York, 556–563.
6.
Imhoff, P. T., and Jaffe, P. R.(1994). “Effect of liquid distribution on aqueous-vapor phase mass transfer in unsaturated sands during infiltration.”J. Contaminant Hydro., 16(4), 359–380.
7.
Ji, W., Dahmani, A., Ahlfeld, D., Lin, J. D., and Hill, E.(1993). “Laboratory study of air sparging: Air flow visualization.”Ground Water Monitoring and Remediation, 13(4), 115–126.
8.
Johnson, R. L., Johnson, P. C., McWhorter, D. B., Hinchee, R. E., and Goodman, I.(1993). “An overview of air sparging.”Ground Water Monitoring and Remediation, 13(4), 127–135.
9.
Karickhoff, S. W.(1984). “Organic pollutant sorption in aquatic systems.”J. Hydr. Engrg., ASCE, 110(6), 707–735.
10.
Mackay, D., Shiu, W. Y., and Sutherland, R. P.(1979). “Determination of air-water Henry's law constants for hydrophobic pollutants.”Envir. Sci. Technol., 13(3), 333–337.
11.
Marley, M. C., Hazebrouck, D. J., and Walsh, M. T.(1992). “The application of in-situ air sparging as an innovative soils and groundwater remediation technology.”Ground Water Monitoring and Remediation, 12(2), 137–145.
12.
Pavlostathis, S. G., and Mathavan, G. N.(1992). “Desorption kinetics of selected volatile organic compounds from field contaminated soils.”Envir. Sci. Technol., 26(3), 532–538.
13.
Rathfelder, K., Yeh, W. W.-G., and Mackay, D.(1991). “Mathematical simulation of soil vapor extraction systems: Model development and numerical examples.”J. Contaminant Hydro., 8(3/4), 263–297.
14.
Szatkowski, A., Imhoff, P. T., and Miller, C. T.(1995). “Development of a correlation for aqueous-vapor phase mass transfer in porous media.”J. Contaminant Hydro., 18(1), 85–106.
15.
Wilkins, M. D., Abriola, L. M., and Pennell, K. D.(1995). “An experimental investigation of rate-limited nonaqueous phase liquid volatilization in unsaturated porous media: Steady state mass transfer.”Water Resour. Res., 31(9), 2159–2172.
Information & Authors
Information
Published In
Copyright
Copyright © 1998 American Society of Civil Engineers.
History
Published online: Nov 1, 1998
Published in print: Nov 1998
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.