Experiment 1: Average Effluent Turbidity vs Velocity - Low Floc Blanket Formation

During Experiment 1, the following capture velocities were used: 0.058 mm/s, 0.116 mm/s, 0.174 mm/s and 0.231 mm/s. This experiment was set on low floc blanket formation.

Figure 1: Average Effluent Turbidity vs. Capture Velocity

Conclusions

As expected, the effluent turbidity significantly higher than that of the control experiment. The presence of saturated water in the influent has a negative effect on the effluent turbidity. In order to quantitatively examine the performance of the experiment with saturated water, data from the control ramp experiment was referenced. The average turbidity for each flow rate tested was graphically compared to the control experiment. The standard deviations, graphed above, give a good idea of the breadth of the data. Comparing the two sets of data, the saturated water experiment had higher effluent turbidity in all cases than that of the control experiment. This data supports the perviously noted observation that the floc blanket appeared cloudy. The bubbles released as a result of a pressure drop in the system disturbed floc formation, allowing less floc particles to settle and more, smaller, lighter particles to leave with the effluent.

Experiment 2: Average Effluent Turbidity vs Velocity - High Floc Blanket Formation

During Experiment 2, the following velocities were used: 5 m/day, 10 m/day, 15 m/day and 20 m/day. This experiment was set on high floc blanket formation.

Figure 2: Average Effluent Turbidity vs. Capture Velocity

Conclusion

There is not a large statistical difference between the saturated water experiment in comparison to the control experiment on high floc blanket formation. This could be due to several reasons. It is possible that because the tube settler was already in the floc blanket, air bubbles went through the system but did not perturb performance locally in the tube settler. Thus, this experiment did not reflect actual conditions. Another explanation is that saturated water did not affect the experiment significantly, but there was another factor causing worsened performance for the 5 m/day data. Based on the large error in the data, it is reasonable to say that there were small perturbations over short periods of time that caused the turbidity to be higher. In other words, the turbidity was not consistently higher.