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The experiment ran for almost 80 hours; results are divided in two plots to facilitate their reading. As can be seen in the first graphfigure, the effluent pH remained above 12 units for a short period of time in comparison with the total time. A1 lasted for 12.5 hours and A2 for 18 hours. It is longer than the results observed in experiment 3. However, it is important to remark that readings above 12.6 were observed; that is not chemically possible due to the saturation pH of lime. Those readings were associated with problems in the pH probes that the team wanted to fix for future experiments. The great drop in pH is due to a trial to calibrate the pH probe; that reading corresponds to buffer solutions.
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