Floc Blanket Formation

Although the plate settler spacing team is not directly concerned about the formation of floc blankets, we cannot ignore how they affect our system because of the effect they have on the quality of the effluent. Floc blankets form at different rates based on how the system is set up; one of the main differences we have noticed is that in the presence of a mesh, the blanket forms much more quickly. This is most likely due to the way the flow is dispersed as a result of the mesh.

For our tests, we have a digital camera set up that takes pictures of the floc blanket during formation. These pictures are taken every minute, allowing us to track the height of the floc blanket at any given time. We have tape on the sedimentation column that marks the height of the floc blanket to use as a reference.

With the Presence of a Mesh

This shows the height of the floc blanket in relation to the time the system has been on. There is a gap at the beginning of the data because there needs to be an initial accumulation of flocs in the colum in order to form a blanket.

We noticed that the latter portion of the graph was linear, and created a trendline to give the data about the rate of formation. This would imply that about an hour and a half into formation, the floc blanket builds at a rate of about 0.3cm per minute. It is hypothesized that during the initial hour and a half, the floc blanket is beginning to form and to compact upon itself, but only starts growing at a steady rate after this time has passed.