Colloid Transport Through Porous Media: Effects of Flow Rate and Aggregation Primary Researcher: Steven J. Kuhlman Advised by: Dr. Kevin Gardner Colloidal associated contaminant transport through aqueous environments has been an increasingly accepted mechanism for dispersion of certain contaminants. The behavior of colloids under varying conditions and their transport through aquifer systems has yet to be fully understood. This project set forth to investigate colloid transport behavior under varying flow fields. Specifically, deposition, aggregation, and the effects of shear stress were investigated. Breakthrough curve deposition experiments were conducted for latex colloids in a glass bead porous media. Shear stress experiments confirmed past findings that showed the colloid deposition rate to be inversely proportional to flow rate (see Figure 1). Measured particle size distributions of the effluent show that aggregated particles tend to have a smaller deposition rate than singlets under the same flow conditions. In addition, the hydrodynamics of the flow through the porous media tended to alter and enhance aggregation rates relative to diffusion-controlled aggregation. Finally, the breakthrough curves were analyzed with respect to the classical Brownian diffusion deposition rate and a physical model for colloid deposition which is analogous to sorption was developed. The very low flow rates and large media utilized in this experimentation allowed investigation of this mechanism that may have been difficult to distinguish in previous experimentation. This physical model, analogous to a sorption model, was implemented in an analytical solution of the convective dispersive mass transport equation in one dimension. This model was calibrated with a least squares parameter fit on ð, the thickness of the immobile fixed film surrounding the media. Optimized values of ð were found to vary between 61.9 and 129 mm and in inverse proportion to flow rate. The fastest flow rate experiment did not allow observation of this deposition mechanism. The modelŐs predicted breakthrough curves agree well with the first two phases of breakthrough while an additional term would be necessary to model the third segment of contaminant breakthrough (see Figure 2). CWRU Department of Civil Engineering Main Menu | Sitemap | Department Activities | On-Campus Menu Communication Click to request a Graduate | Undergraduate Application Form. Click to get in touch with a Graduate | Undergraduate Student. Click to Schedule a Tour of the Department.