Wu, M., J. Wu, J. Wu, and B.X. Hu.
Hydrology and Earth System Sciences 22(2):1001-1015(2018)

Two different microscale arrangements of sand particles were compared to reveal the effects of microstructure on contaminant migration and remediation. With the help of fractal theory, the mathematical expressions of permeability and entry pressure were conducted to delineate granular materials with regular triangle arrangement (RTA) and square pitch arrangement (SPA) at microscale. Using a sequential Gaussian simulation method, a synthetic heterogeneous site contaminated by PCE was then used to investigate the migration and remediation affected by two different microscale arrangements. PCE was released from an underground storage tank into the aquifer, and surfactant was used to clean up the subsurface contamination. Results suggest that RTA materials can not only expand groundwater contamination but also make remediation more difficult. PCE remediation efficiency of 60.01-99.78% with a mean of 92.52 and 65.53-99.74% with a mean of 95.83% was achieved for 200 individual heterogeneous realizations based on the RTA and SPA, respectively, indicating that the cleanup of PCE in an aquifer containing SPA materials is significantly easier. This study leads to a new understanding of the microstructures of porous media and shows how microscale arrangements can affect contaminant migration in aquifers. https://www.hydrol-earth-syst-sci.net/22/1001/2018/hess-22-1001-2018.pdf