Apparatus Changes - Progress

New Setup

In order to prevent premature sedimentation in the flocculator, we have changed the flocculator setup. The flocculator hollow PVC tube (black) has been replaced with a peg board by which the team can plug in pegs to wrap the flocculator tube around. The board is 75 inches tall by 35 inches wide and is supported by a wooden brace to stand vertical.

The flocculator tube wraps around 10 different pegs that form semi-circles on the vertical ends of the board. The 50 foot flocculator tube wraps around these pegs about three times between rapid mix and the settling column.
If the team wanted to shorten the vertical distance that the tube wraps around, it is an easy transition by just replacing the pegs to a different hole on the board. This new setup is convenient and provides a lot of different ways to achieve a vertical flocculator.

This new setup reduces the amount of horizontal pieces in the flocculator, and will hopefully reduce or remove the amount of settling altogether.

Pictures

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From Left to Right:
1) new tube flocculator setup on the board
2) Effluent Turbidimeter
3) The settling column with straight inlet and outlet (straws at the top)
4) Top of the new tube flocculator setup

Data Analysis

Data Analysis for the new flocculator setup can be viewed here.

Changing the Apparatus Setup for Turbulent Flow

In order to achieve turbulent flow in our flocculator setup, we needed to figure out if our pumps can handle very high flow rates to get high Reynolds number. For turbulent flow, our target Reynolds number is 2500, with flocculator inner diameter of 0.6cm. The calculation shows that the flow rate needs to be at least 11.8 mL/s for turbulent flow. (With our current setup, the max flow rate is 3.1 mL/s) Thus, one of our solutions was to add more pump heads, since the max flow rate of pump is limited by how fast a pump head motor can rotate.

In order to test out how many additional pump heads are needed, we added in new set points to Process Controller method - "3-Alum Number of Heads" and "3-Clay Number of Heads". We found that 2 alum pump heads, 2 clay pump heads, and 3 raw water pump heads are sufficient to provide our target flow rate of 11.8 mL/s.