Spring 2008 Demo Plant Sedimentation Tank Design

The new sedimentation tank design proposed in Spring 2008 will address the problem of uneven flow lengths, rates, and shears through each lamella of the sedimentation tank in the Spring 2007 Demo Plant. This problem is further described in the Demo Plant Problems Encountered page.

The proposed sedimentation tank will be oriented perpendicular to the axis of the flocculator. Additionally, to accommodate the new design, water will exit the flocculator from the top, instead of the bottom. In order to eliminate differences in lengths of flow paths through the sedimentation tank, water exiting the flocculator will be split into several tubes of equal diameters and lengths, which will enter the bottom of the sedimentation tank. The tubes entering the sedimentation tank will be evenly spaced.

The sedimentation tank itself will be redesigned so that lamella still form the optimal 60 degree angle. However, the lamella will now guide the water in a path parallel to the axis of the flocculator, so that the whole tank will have an incline, and will need to be either very bottom-heavy, or have a support for the upper ends of the lamella. This design, along with the new entry method, will normalize the head loss through individual channels in the sedimentation tank.

The proposed sedimentation tank will also incorporate an open-top design, similar to the flocculator of the Fall 2007 Demo Plant.

This design also allows us to consider the incorporation of a drain for built up sediments in the sedimentation tank, adding the functionality to clean the sedimentation tank while the plant is still running.