Department of Civil Engineering, Kansas State University, Manhattan, KS, 66506, 913-532-1586
By virtue of their large surface area and high sorption potential, fine clay particles adsorb significant quantities of subsurface contaminants and may be considered particulate contaminants. Understanding the mobility of these particulate contaminants in porous media is essential to predict the contaminant transport in ground water. In a geoenvironmental engineering context, the mobility of the fine particles has recently been viewed as desirable in subsurface remediation. The stability of these particles depends on both physical and chemical effects induced through pore water flow. The combined effect of dynamics and composition of pore fluid may significantly alter the permeability and transport characteristics of the porous media. In this study, various hydraulic gradients were considered in a theoretical analysis to account for the effect of pore fluid dynamics on the mobility of the contaminants. Pore fluid characteristics such as ionic strength and valency were considered in the analysis by accounting for London-van der Walls attractive forces and electrical double-layer attractive or repulsive forces. The study addresses the interaction of forces at a microscopic level acting on individual clusters of particles to assess the significance of the two effects. Finally, the significance of the fine particle stability is assessed in light of the standard transport mechanisms (advection and diffusion).
particulate contaminants, pore fluid, permeability, porous media, transport mechanism
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.