RESIDUAL SATURATION OF PACKED-COLUMNS WITH CHLORINATED SOLVENTS

Sparingly soluble organic contaminants (non-aqueous phase liquids or N APLs) spread laterally at the interface between layers of differing pe rmeability, in porous media, due to capillary forces. Less dense (than water) substances infiltrate and become trapped at the capillary frin ge. More dense substances (dense non-aqueous phase liquids or DNAPLs) penetrate to and through the saturated zone after passing through the unsaturated zone. However, residual DNAPL remains trapped as discrete pendular, funicular and capillary bodies. A Model has been developed t o estimate residual retentions in two-phase (DNAPL-water) systems unde r unsaturated (vadose zone) conditions, in the presence of air. (C) 19 98 Elsevier Science B.V. All rights reserved.