Experiment 2: Alum Dose = 35 mg/L
An alum dose of 35 mg/L is considered to be an under dose. The below graphs show the effluent turbidity vs. time for the same capture velocities used for Experiment 1.
Figure 1. Effluent Turbidity vs. Time, floc blanket on low, alum dose 35 mg/L.
Figure 2. Effluent Turbidity vs. Time, floc blanket on high, alum dose 35 mg/L.
Conclusions
Based on the results of this experiment, and alum dose of 35 mg/L is not an under dose. The system performed above expectations, so we are going to test the system with an alum dose at 25 mg/L to see how the tube settler performs with an actual under dose.
(Explain if possible the discrepancy between 15 and 20 m/day capture velocity. Why for the high is 15 m/day performing worse than 20 m/day? If you can't explain it, then it is an abberation and perhaps has to be re-run.)