Numerical modeling of colloid-assisted BTEX transport in a saturated fractured aquifer

Colloid occurrence is a crucial factor influencing the movement of hydrophobic components like petroleum hydrocarbons in fractured aquifers. In this study, an attempt is made to examine the influence of colloids on the movement of Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) in a saturated fractured rock aquifer. A numerical model is developed to simulate the colloid-BTEX co-transport in a fracture-matrix system (F-M-S). The modeling investigation is performed by adopting the dual-porosity modeling approximation for the fractured aquifer. The study's outcome suggests that the colloid influence is more on the transport of less soluble BTEX components: ethylbenzene and xylene. The colloid presence does not influence the Benzene (component with the highest pure phase solubility) movement in F-M-S. The impact of various colloid parameters such as velocity, inlet concentration, filtration rate at fracture-matrix interface, attachment rate on the fracture surface, on BTEX transport in fracture and matrix, is estimated. Migration of Toluene, Ethylbenzene, and Xylene (TEX) in fracture and matrix is turned out to be sensitive to these parameters. The peak dissolved concentration and the peak location of these components are found to be sensitive to these parameters. The colloid impact on the dissolved concentration levels of TEX is more evident in the later simulation stages.