Author: AguaClara Pilot Plant Spring '08 Sub-Team

Sections on Testing of the Tapered Flocculator were written by:
* Rebecca Thompson: rnt3@cornell.edu
* Narayana Pappu: nvp4@cornell.edu

h2. Developing Turbidity Profiles along the Flocculator


h4. Profile Test Procedure

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h5. Picture of the Flocculator set-up.
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h5. Experimental Set-up of the Tube Settler Placement.
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The purpose of this experiment was to develop a profile of flocculation at different places along the flocculator. In order to do this, we moved the tube settlers to different points along the length of the flocculator and tested the turbidities of the water after it passed through the tube settler and reached the turbidimeter. In Experimental Set-up of the Tube Settler Placement above, you can see a schematic of the experimental set-up. A photograph of the same set-up is also shown. The experiment has three parts, A, B, and C, each lasting for 45 minutes. During the experiment, the location of tube settlers 2 and 3 were moved to different places along the flocculator as shown above. Turbidimeter 1 was always testing the incoming water, and turbidimeter 4 was always testing the turbidity of the water at the end of the flocculator (location 4 above). Along with moving tube settlers 2 and 3, we emptied tube settler 4 of water between parts A, B, and C of the experiment. This is because when the tube settler is filling with water, plug-flow conditions exist in which velocity gradients cannot develop, and flow up the tube settler is more even. So, by emptying tube settler 4 of water, we ensured that the potential effects of this condition in the tube settler were even across all the tube settlers.
Likewise, when performing the data analysis after the experiment, we found an increase in the turbidity to unreasonably high levels (on the order of 100 NTU) for about 10 minutes after moving the tube settlers. This was because the air in the tube settlers which was being pumped through the turbidimeters. Therefore, only the data at the end of each part of the experiment was used (approximately after 10 minutes of running). The removal of the air can be easily observed in the data when the system appears to have reached a steady-state.