Solute transport in aggregated media: Aggregate size distribution and mean radii

Abstract

An aggregate model was employed to study the effects of aggregate size distribution (ASD) on solute transport in a column. Instantaneous local sorption equilibria and nondegradation were assumed. The aggregate model was solved using an effective new iterative numerical scheme. Three ASDs from the literature were used in the calculations. The effects of aggregate size and size distribution can not be separated and are influenced by the flow regimes of the system. A mean variance radius was derived. This mean variance radius depends on the internal diffusion and mass transfer coefficient of the aggregates. It provided the best approximation among other types of mean aggregate radii used in the literature. Multiple mean variance radii should be used to represent the ASDs.