Laboratory Investigation of Residual Liquid Organics from Spills, Leaks, and the Disposal of Hazardous Wastes in Groundwater

摘要

Organic liquids that are essentially immiscible with water migrate through the subsurface through the influence of capillary, viscous and buoyancy forces. Four experimental methods were employed. First, quantitative displacement experiments using short soil columns; second, additional quantitative displacement experiments using long soil columns; third, pore and blob casts; and fourth, etched glass micromodels were used to visually observe dynamic multi-phase displacement processes in pore networks. It was found that the spatial distribution and saturation of organic liquid within the porous media depends on a variety of factors, including: (1) the fluid properties of interfacial tension, viscosity, and density; (2) soil structure and heterogeneity; (3) the number of fluid phases present; and (4) the fluid flow rates. Photomicrographs on a pore scale show that the residual organic liquid appears as blobs, films, rings, and wedges of microscopic size. The size, shape, and spatial distribution of these blobs, films, rings, and wedges affects the dissolution of organic liquid into the water phase, volatilization into the air phase, and the adsorption and biodegradation of organic components. These four processes are of concern in the prediction of pollution migration and the design of aquifer remediation schemes.