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Figure 3 shows the three ramp states as a function of flow rate. The first ramp state has a significantly higher turbidity than the following two. This suggests that this film may have an effect on the performance of the filter. In order to prove or disprove this, experiments will be run with the filter column on its side so this film is unable to perform, and by comparing these results, we will find out reveal the importance of the film layer. Also, it is important to note that with this lower alum dose, not as many of the smaller particles are being made "larger" or "sticker" from contact with alum, since there is less alum to come in contact with. Therefore, the minimum turbidity achieved with a low alum dose is not as low as the minimum turbidity achieved with the high alum dose. This factor makes the turbidity levels achieved seem constant, versus the linear function achieved in Figure 1. However, Figure 1 and Figure 3 are actually showing similar results, with the exception that the higher alum dose is able to trap smaller particles at lower flow rates since more will come in contact with the alum. This can not be done with the lower alum dose, so the results appear to be more constant with flow rate.
Figure 3: Effluent Turbidity vs. Flow Rate
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