Effects of microarrangement of solid particles on PCE migration and its remediation in porous media

Abstract

Abstract. Groundwater can be stored abundantly in granulacomposed aquifers with high permeability. The microstructure of granular materials has important effect on the permeability of aquifers and the contaminant migration and remediation in aquifers is also influenced by the characteristics of porous media. In this study, two different microscale arrangements of sand particles are compared to reveal the effects of microstructure on the contaminant migration and remediation. With the help of fractal theory, the mathematical expressions of permeability and entry pressure are conducted to delineate granular materials with regular triangle arrangement (RTA) and square pitch arrangement (SPA) at microscale. Using a sequential Gaussian simulation (SGS) method, a synthetic heterogeneous site contaminated by perchloroethylene (PCE) is then used to investigate the migration and remediation affected by the two different microscale arrangements. PCE is released from an underground storage tank into the aquifer and the surfactant is used to clean up the subsurface contamination. Results suggest that RTA can not only cause more groundwater contamination, but also make remediation become more difficult. The 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 % is achieved for 200 individual heterogeneous realizations based on the RTA and SPA, respectively, indicating that the cleanup of PCE in aquifer with SPA is significantly easier. This study leads to a new understanding of the microstructures of porous media and demonstrates how microscale arrangements control contaminant migration in aquifers, which is helpful to design successful remediation scheme for underground storage tank spill.

Simulação geoestatística e numérica para previsão da eficiência da remediação por oxidação química in situ

“…Em meios heterogêneos, a variação aparentemente errática do K e a incerteza de sua distribuição requer sua modelagem como função espacial aleatória, o que implica na necessidade do emprego de simulações estocásticas (FIORI et al, 2016). A avaliação das incertezas da eficiência de diferentes alternativas remediação decorrentes de heterogeneidades geológicas por intermédio de simulações estocásticas já foi previamente abordada em diversos trabalhos, exemplificando os trabalhos de Mylopoulos et al (1999), Lemke & Abriola (2003), Moreno & Paster (2017), Jiang et al (2018) e Wu et al (2018). Trabalhos abordando o emprego de simulações estocásticas para avaliar as incertezas relacionadas à remediação por ISCO em aquíferos heterogêneos, embora relevantes, são bastante escassos.…”