Visualization Studies of Dense Leachate Plumes in Porous Media

In this paper, a series of flow visualization experiments investigating the behavior of dense leachate plumes are described. These experiments were performed in various flow containers which simulated phreatic aquifers. Relevant experimental parameters (saturated hydraulic conductivity K sat , horizontal Darcy velocity q x , leachate density ρ c , leachate loading rate Q L ) were varied in a systematic way, and the leachate plume behavior was observed and photographed. Experimental results show that an increase in the contrast between the leachate plume density and the ambient groundwater density results in an increase in the overall plume penetration depth. Additionally, under certain combinations of the experimental parameters, three-dimensional, time-variant instabilities may develop within the plumes. This phenomenon enhances the mixing of the plume with the ambient groundwater.