Simulation of Hindered-Settling Column Separations for Soil Remediation

Abstract

A phenomenological model was developed to describe the operation of a hindered-settling column. The model is based on the convection-diffusion equation as applied to hindered-settling conditions. Simulation results for the size classification of soil were compared with experimental results to validate the model. Subsequent simulations were carried out to evaluate column performance for separating heavy metal or organic contaminants from soil. The simulation results are presented in terms of fractional recovery (partition) curves, which give the probability that feed particles of a given size and density will be recovered in the column underflow stream. The results indicate that good separations are possible down to approximately 75 µm in some cases. The effective size range of separation depends on the design and operating conditions of the hindered-settling column and on the material being processed.

Keywords:

• Soil washing
• Waste remediation
• Density separation
• Gravity concentration
• Teeter bed