|Van Genuchten, Martinus|
Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 7/10/2005
Publication Date: 10/1/2005
Citation: Bradford, S.A., Van Genuchten, M.T., Simunek, J. 2005. Modeling of colloid transport and deposition in porous media. Proceedings of the workshop on HYDRUS Applications, Oct. 19, 2005, Utrecht Univ., The Netherlands. p. 1-5. Interpretive Summary: This paper discusses recent advances in the HYDRUS computer model that is used to simulate the transport and fate of pathogenic microorganisms and other colloidal sized particles in soil and aquifer systems. Topics of discussion included the retention and transport velocity of colloids in soil environments.
Technical Abstract: A conceptual model for colloid transport is presented that accounts for colloid attachment, straining, and exclusion. Colloid attachment and detachment are modeled using conventional first-order rate expressions, whereas straining employs a first-order term that is depth-dependent. Time dependent colloid deposition as a result of blocking of favorable attachment sites or filling of straining sites is simulated using a Langmuirian type expression. The influence of colloid-colloid interactions on straining is also included using at term that is proportional to the concentration of colloids in suspension and strained on the solid phase. Finally, size exclusion is modeled by adjusting transport parameters for the colloid-accessible pore space. Numerical simulations are presented to highlight the various processes controlling colloid transport and deposition. The sensitivity of simulation results to selective model parameters is also demonstrated.