Removing Contaminants in a Secondary Sedimentation Clarifier

Wastewater treatment is a several-step process for removing contaminants. Firstly, large, solid particles are removed through sedimentation, flotation, and filtration. And then in a second step, biological treatment causes the smaller particles to aggregate, forming so called flocs. These flocs can be more easily removed by processes such as sedimentation.

In a circular secondary clarifier, flocs are removed from water through sedimentation, where gravity causes the flocs to fall toward the tank bottom. However, the turbulent flow in the tank tends to mix the phases together, and thus has a negative effect on the separation.

This example studies the separation of flocs from water in a circular secondary clarifier. The object is to study the complex turbulent multiphase flow using the Mixture Model application mode.

Revolved plot of the 2d model showing the volume fraction of the dispersed phase as a boundary plot and a streamline plot of the velocity field.