...
Below in figures 1, 2 and 3 is the preliminary data from the experiment. The 2.5 cm plate settler was relatively stable, achieving a pH of over 12 for well over a week! The 5 cm plate settler, however, never reached a pH of 12 but rather oscillated around a value of approximately 11.5. As time went on, the amplitude of the data's wave increased and the pH started regularly dipping below 10.
Figure 1 - Experiment 9
The above graph is hours 0 to 40 of an experiment pulsing in 41.5 g/L of lime slurry at 380 mL/min for 1 minute every six hours.
Figure 2 - Experiment 9
The above graph is hours 40 to 80 of an experiment pulsing in 41.5 g/L of lime slurry at 380 mL/min for 1 minute every six hours.
Figure 3 - Experiment 9
The above graph is hours 80 to 120 of an experiment pulsing in 41.5 g/L of lime slurry at 380 mL/min for 1 minute every six hours.
Experiment 9 ran for nearly 10 days before the team shut it down. The performance of the 2.5 cm tube settler remained pretty consistent, with the pH remaining right around 12. The 5 cm tube settler continued its wave-like motion, as seen in Figure 4.
Figure 4 - Experiment 9, Day 9
This graph is zoomed in to display that the smaller apparatus does experience slight peaks with each lime pulse, and to not that the larger apparatus dips below a pH of 10 as the experiment continued.