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The data processor failed to fit a curve on the gamma PDF graph . We speculate this is because at 5 NTU, the water is more difficult to flocculate because it is such a low turbidity and the fact that at the original length did not allow for enough time for flocs to form. using our turbidity data Thus, the turbidity data did not fit the statistical distribution function (a gamma pdf) that we are using.

Because We speculate failure of the data to fit because the experiment was conducted with such a low influent turbidity, there are less colloidal particles present in the water and less probability for these particles to collide with one another. Hence, for this experiment, the shortness of the flocculator and the limited effect of the alum caused the failure of producing a significant improvement in the turbidity of the water. There will need to be a higher collision potential for these particles to successfully collide and create bigger flocs necessary for a successful flocculation. The residual turbidity graph (Figure 1) shows the resulting mean turbidity settling down to around 2 NTU starting from the alum dose of 20 mg/L. (I see what you are trying to say. Condense this section about why you fail to fit the gamma function and then speculate the cause. We cannot say for certain.)

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FIGURE 1: The graph plots the residual turbidity vs. sedimentation velocity for each Alum dose ranging 10 mg/L~50 mg/L

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Looking at the gamma PDF curve (Figure 2A) the alum dosage of 10 mg/L demonstrates an unusual behavior compared to the other doses(I suspect ; it has a very narrow distribution focused at a particular sedimentation velocity. It is suspected that the statistical functions you we used to fit the data, did not fit the data right. 10 mg/L had a high residual turbidity and thus we should have a large portion of particle sizes in the lower sedimentation velocities. Either Also, it could possibly be the case that this resulted from an unexpected presence of a large floc that might not have been representative of 10mg/L dosage but rather at the time the process controller recorded that reading a large floc happened to intersect. An option would be to either re-run the experiment or we should accept that we cannot fit it to the data. Otherwise 20 and 30 mg/L follow the trend well) ; it has a very narrow distribution focused at a particular sedimentation velocity. We suspect that this has been resulted from an unexpected presence of a large floc that has not necessarily been produced from the flocculator (Then where was it produced?). From the residual turbidity graph (Figure 2B), there is also an unusual trend with the alum dose 40 mg/L; its turbidity unexpectedly peaks and results in an unusually high mean turbidity. (Can you speculate as to why this is the case?) In figure 2A, the alum doses 20 and 30 mg/L have wider distributions of floc sizes compared to those of other alum dosesdosages. The wider distributions (Comment on why they have wider distributions. Can you comment on the average particle size? Are they higher or lower) Overall, there seems to be discrepancies between the data recorded in the two graphs. From the values of mean turbidity at settling state, from 10 to 45 mg/L the mean turbidity seemed to start at a value of .608 NTU then rise to about .725 at 25mg/L, then rises to .829 and then back down to .755 at 35 mg/L.

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