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Title (Primary) Air sparging for contaminant removal: theory
Title (Secondary) Encyclopedia of Agricultural, Food, and Biological Engineering, 2. ed.
Author Tilma, M.; Hilkert, E.J.; de Rooij, G.H.; Jesiek, J.; Mohtar, R.H.;
Publisher Heldman, D.R.; Moraru, C.I.;
Year 2012
Department BOPHY;
Language englisch;
Abstract Remediation of soil and groundwater contaminated with volatile organic compounds (VOCs) continues to
pose a major public challenge. Further understanding of the contaminant transport processes during cleanup
can improve innovative in situ remediation techniques such as air sparging (AS) (injecting pressurized air
through the soil). This entry presents an example study that uses a laboratory-scale contaminated soil column
to study the relationships among the soil medium, airflow, and contaminant transport and transfer through
liquid, air, and dissolved phases during air injection. We injected toluene and ethylbenzene into a saturated
soil column and applied several airflow regimes to remove the contaminants. Tenax resin trapped the
contaminant in the air stream leaving the column, and the resin trap effluent and soil water samples taken
at various heights in the column were analyzed. At the end of each experiment, residual contaminants in the
soil column were determined. Our results show that the initial contaminant removal was higher with higher
airflow rates until the contaminant removal became diffusion-limited and the removal process slowed down.
The contaminant concentration profiles along the soil column suggest that the combined advective air stream,
air bubbles, water flow, and upward movement of silt particles increased the contaminant concentration at the
top of the column and reduced the concentration in the middle of the column. Simultaneous injection of
toluene and ethylbenzene showed trends similar to single-contaminant injection. Air pulsing expedited
contaminant removal in the column, possibly by turbulent mixing and driving the system away from
diffusion-limited removal. These observations are consistent with other literature findings.
ID 13660
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=13660
Tilma, M., Hilkert, E.J., de Rooij, G.H., Jesiek, J., Mohtar, R.H. (2012):
Air sparging for contaminant removal: theory
In: Heldman, D.R., Moraru, C.I. (eds.)
Encyclopedia of Agricultural, Food, and Biological Engineering, 2. ed.
CRC Press / Taylor & Francis, Boca Raton, FL, p. 1 - 5