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The wider tube settlers, as expected, provided more sensitive data. That is, the effluent turbidity was directly impacted by changes in flow rate, floc blanket height, and tube diameter. The table and graph below illustrates illustrate the average effluent turbidity for the three diameters described in the methods section above.
Table 2. Results
As the results show, the second lowest capture velocity for each diameter tube resulted in the optimum settling efficiency at the low floc blanket height. The results also show a general trend of increasing effluent turbidity once the capture velocity exceeds 11.0 m/day. This indicates that the current capture velocity design to in the current plants is appropriate.
what are the newest small tube data? this data could probably be reworked to fit better.
_The plot below displays the effluent turbidity vs. critical velocity graphed on a semi-log plot. Each flow state was run for 6 hours, however, the floc blanket was at the high setting of 60 cm, as opposed to the desired low setting, due to air blocking the flow through the solenoid valve. There were also error in both the initial calculations of the flow rate and the tubing size. Instead of testing at a Vc range of 5 to 20 m/day a much higher Vc range of around 39 to 131 m/day. The results are display in the graph below.
Graph 1 The average effluent turbidity of the 9.5 mm tubes at a high floc blanket, with very high Vc values.
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