Data Fluctuation
Our team ran a typical experiment multiple times repeatedly to see how the effluent turbidity data fluctuated during the settling state in each experiments and to compare the data fluctuation between experiments. The experiment set up was an influent turbidity of 50 NTU, a flocculator length of 25 feet, and a G of 3.1 1/s. We repeated this experiment at least ten times in a row. We extrapolated the data from just the settling state (600 seconds), we found the average and standard deviation of the influent turbidity and the effluent turbidity separately at each second interval.
Figure 1: Standard Deviations of the Influent and Effluent Settling Turbidities from 10 consecutive experiments using the same position of the settling column (top).
Figure 2: Standard Deviations of the Influent and Effluent Settling Turbidities from 10 consecutive experiments using a new position of the settling column (bottom).
The effluent turbidity standard deviations in both positions have a large range(Figure 1 and 2), and there is a trend of increasing standard deviations as the settling state time increases. The max standard deviation for the effluent turbidity when the turbidimeter was in its standard position (top) is 12.4. The max standard deviation for the effluent turbidity when the turbidimeter was in its new position (bottom) is 14.2. The influent turbidity standard deviations in both positions are generally lower than the effluent turbidity standard deviations, and maintain at low values.
These results definately show us some insights into our data. We see that the settling data in one experiment will not be the same as in the next experiment (when all variables of the experiment remain the same).