Department of Civil Engineering, Seaton Hall, Kansas State University, Manhattan, KS, 66506, 913-532-1586, FAX 913-532-7717, E-MAIL firstname.lastname@example.org and email@example.com
The residual NAPL (non-aqueous phase liquid) ganglia remain entrapped in the saturated domain, posing a problem of paramount importance in ground water remediation. This paper addresses pumping with either pulsed or monotonic accelerations to recover trapped NAPL. Laboratory tests were conducted on both glass beads and sands to investigate the mechanisms involved. The results reveal that the durations of the accelerations are as important as the magnitudes in causing recovery. Though lower accelerations induce lower viscous forces, they allow unhindered transport of mobilized ganglia. Higher accelerations on the other hand result in sudden mobilization of a larger population of ganglia, consequently stranding them. The results are explained using capillary number approach that accounts for the effect of accelerations. The results suggest that controlled accelerations may be utilized for in situ recovery of residually trapped NAPL ganglia. This study provides a rational basis for implementation of pulsed pumping in the field. Ongoing studies are oriented towards optimizing the pulse pumping parameters for maximal recovery.
NAPL ganglia, pulse pumping, pore fluid accelerations, capillary number
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.