Apparatus Changes
Concerns
The Tube Floc research team has known for a while now that sedimentation was occurring within the flocculator and that such premature sedimentation was bad. The switch from a horizontally coiled flocculator to a vertically coiled one was made partly to try to overcome this issue. Throughout the Fall 2007 semester, the Lab Floc team performed numerous experiments with the flocculator apparatus despite not having completely eliminated sedimentation. It seemed, at the time, that the sedimentation accrued per run was minimal and that it would not contribute a significant amount of error into our measurements. However, further investigation by the Lab Floc team this semester has given new light into the significance of this premature sedimentation as well as a new problem of circulation of fluid inside the settling column immediate after the termination of flow through the apparatus. These issues are significant not only because they are unexpected and not optimal experimental conditions, but they also put into question the validity of the data obtained last semester and the method by which we have been analyzing and describing these past results. Below are more detailed discussions of the different aspects of these problems.