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COLLOID MOBILIZATION AND TRANSPORT IN CONTAMINANT PLUMES: FIELD EXPERIMENTS, LABORATORY EXPERIMENTS, AND MODELING (EPA/600/S-99/001)
Citation:
Ryan, J. N., R. A. Ard, R. D. Magelky, M. Elimelech, N. Sun, AND N. Sun. COLLOID MOBILIZATION AND TRANSPORT IN CONTAMINANT PLUMES: FIELD EXPERIMENTS, LABORATORY EXPERIMENTS, AND MODELING (EPA/600/S-99/001). U.S. Environmental Protection Agency, Washington, DC, 1999.
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Description:
The major hypothesis driving this research, that the transport of colloids in a contaminant plume is limited by the advance of the chemical agent causing colloid mobilization, was tested by (1) examining the dependence of colloid transport and mobilization on chemical perturbations, (2) assessing the relative transport of mobilized colloids and the chemicals that caused their mobilization, and (3) developing a colloid transport model that would begin to describe these effects. Through filed tests, laboratory experiments, and model development, we made significant advances toward the testing of the hypothesis. The field tests, conducted in the uncontaminated zones of a ferric oxyhydroxide-coated quartz sand aquifer, showed in almost all cases that colloids will not advance ahead of the plume that caused their mobilization. The laboratory experiments showed chemical perturbations that cause increasingly repulsive conditions produced more extensive and more rapid colloid release. In both the field and laboratory experiments, good correlations were observed between the surface properties of the colloid and aquifer grains and their transport and mobilization behavior. The colloid transport model was developed to describe colloid transport in physically and geochemically heterogeneous porous media similar to that encountered at the field site. The model results showed that physical and the geochemical heterogeneities could result in preferential flow of colloids in layered porous media, while random distributions of the two heterogeneities, especially the physical heterogeneity, lead to a random behavior of colloid transport.
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COLLOID MOBILIZATION AND TRANSPORT IN CONTAMINANT PLUMES: FILED EXPERIMENTS, LABORATORY EXPERIMENTS, AND MODELINGCOLLOID MOBILIZATION AND TRANSPORT IN CONTAMINANT PLUMES: FILED EXPERIMENTS, LABORATORY EXPERIMENTS, AND MODELING (PDF, NA pp, 1178 KB, about PDF)