Department of Civil Engineering, Kansas State University, Manhattan, KS, 66506, 913-532-1586, FAX 913-532-7717, E-MAIL reddi@ksuvm.ksu.edu and smenon@ksu.ksu.edu
The mobilization of discrete ganglia, formed by the residual entrapment of NAPL (non-aqueous phase liquids) in the soil, is of utmost importance in subsurface remediation. This paper utilizes a network modeling approach to address the stability of ganglia of various dimensions and to come up with probabilities of mobilization, stagnation and break-up of individual ganglia. A random allocation of pore-sizes and connecting pore-throats is carried out, and the stability of a given ganglion is studied by using a mobilization criteria at each of the nodes it occupies. The approach takes into account spatial and temporal changes in capillary number during pumping due to changes in pumping velocities and accelerations. It also takes into account the changes in capillary number due to possible changes in pore structure. The model is used to study the effect of a number of random pore-size and pore-throat allocations of a given pore-size distribution, on a single ganglion. Using these results, the mobilization and stagnation probabilities are determined. Results from column and micromodel experiments are used to assess the usefulness of network modeling in evaluating the fate and transport of NAPL ganglia.
NAPL, network modeling, mobilization, stagnation probabilities
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.