Transport of edible oil emulsions in clayey sands: 3D sandbox results and model validation

Injection of edible oils into the subsurface can provide an effective, low-cost alternative for stimulating anaerobic bioremediation processes. However, concerns have been raised about the effects of oil buoyancy and variations in aquifer permeability on the final distribution of oil in the subsurface. Three-dimensional (3D) sandbox experiments (1.2 m x 0.98 m x 0.98 m) were conducted to study the distribution of edible oil emulsions under homogeneous and heterogeneous conditions. A fine emulsion was first injected followed by chase water to distribute the emulsion throughout the sandbox. This approach was very effective, resulting in a reasonably uniform volatile solids distribution in the top, middle, and bottom layers, measured 5 and 7 weeks after the completion of emulsion injection. A standard colloidal transport model that includes a Langmuirian blocking function was used to simulate emulsion transport and retention in the 3D sandbox. All parameters for the emulsion transport model were measured independently. Simulations results generally matched observed values for both the homogeneous and heterogeneous injection tests demonstrating that this approach can be used to describe the transport and distribution of emulsified oil in sandy sediments.