Abstract:
In the remediation injection of remedial amendment into groundwater, the amendment migration occurs mainly in the high permeability and hydraulically accessible zones, which results in the invalid contaminants removal in the low permeability zones. Using polymer (Xanthan gum fluid) to control the viscosity of groundwater can enhance the remedial amendments migration into low permeability zones, and improve the remediation efficiency. The migration of viscous fluid in the formation is the theoretical basis for the application of this technique. Therefore, in this study the sand-column one-dimensional simulations are used to analyze the characteristics of retention of the Xanthan gum fluid in the aquifer medium, the change in pressure and hydraulic conductivity before and after injection of Xanthan gum, and the synchronization migration of the Xanthan gum and KMnO4.The results indicate that when The Xanthan gum fluid was injected into the medium, the residual of The Xanthan gum led to the decrease in effective porosity, thus accelerating the solute transport in the subsequent solution to a certain extent. The greater the retention contributions are, the smaller the medium permeability conductivity is. The injection of the Xanthan gum fluid resulted in the decrease in the aquifer permeability, and increased the resistance of fluid migration. Especially, the hydraulic conductivity of fine sand and silt sand was reduced by an order of magnitude. There are some differences in the cover of migration of the KMnO4 and the Xanthan gum. After 2 h, the migration rate is basically the same with good synchronization.