REMOVAL OF A MIXTURE OF IMMISCIBLE LIQUIDS BY IN-WELL AIR SPARGING

P. Gandhiš, L.E. Erickson˛ and L.T. Fan˛

šTapanAm Associates, Inc., 8010 State Line, Leawood, KS, 66208 and ˛Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, 913-532-5584


ABSTRACT

The performance of the in-well air sparging process has been examined for cleaning up a site contaminated with a mixture of non-aqueous phase liquids (NAPLs). The process remediates in situ a contaminated aquifer by combining chemical, physical and biological processes. A blower at the top of the well induces upward motion of air and water in the well, thereby creating a circulatory flow pattern in the aquifer. The flow of water in the aquifer has been modeled as a potential flow between the sources and sinks.

Biodegradation may be enhanced by installing a packed-bed bioreactor within the well casing. Since oxygen-enriched water flows out of the bioreactor into the aquifer at the upper screened segment of the well, biodegradation is also enhanced in the aquifer. The results of simulation demonstrate that the compositions of the NAPLs in the aquifer vary with time and that the size of the packed-bed bioreactor influences the pathway through which the contaminants are removed from the aquifer. As a general rule, however, biodegradation plays a more dominant role in removing the less soluble contaminants.

KEY WORDS

aquifer, biodegradation, modeling, air sparging

This paper is from the Proceedings of the 10th Annual Conference on Hazardous Waste Research 1995, published in hard copy and on the Web by the Great Plains/Rocky Mountain Hazardous Substance Research Center.