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Using the Spring 2009 team's process controller methods, we subjected an ideal geometry to non-ideal conditions. Specifically we altered the alum dose to see how different alum doses affected the effluent turbidity. Though the Spring 2009 team had success with a 9.5 mm diameter tube, due to what we think was ineffective air bubble traps in the flocculator, or the addition of a flow accumulator to the method, we experienced failure with this geometry. We achieved an acceptable effluent turbidity (less than 1 NTU) with a 15.1 mm diameter tube that had a length of 30.5 mm. With the good experimental results, we then subjected this tube settler to varying alum dosage to investigate the affect of dosing on tube settler performance. At each alum dosage, the tube settler was tested at a variety of capture velocities and at two different floc blanket levels: the lower level is when the height of the floc blanket falls below the bottom of the tube settler, the high floc blanket level is when the floc blanket height is above that of the bottom of the tube settler.
Alum Dosing Theory
Experiment 1: Alum Dose = 45 mg/L
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