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Figure 1: Raw Water and Effluent Turbidity vs. time for a flow rate of 100 m/day
A few things to note about the graph aboveFigure 1:
- When 5 NTU raw water is sent through the filtering device, the effluent water turbidity is about 2 NTU for the first 6 hours and slightly improves to about 1.5 NTU.
- The clay stock ran out after 14 hours, as evidenced by the drop in turbidity in the raw water.
- It is interesting to note that despite the drop in raw water turbidity, the filter is still effective. Raw water of about .6 NTU was filtered to about .12 NTU.
Figure 2: pC* vs. time for a flow rate of 100 m/day
The graph above Figure 2 is a plot of pC*, which is the percent of colloid removal.
A few things to note about Figure 2:
- The percent removal is approximately constant with time, though it does show some improvement in the first several hours.
- Even when the raw water turbidity dropped after 14 hours, the percent removal of colloids remained constant. This indicates that the percent colloid removal is independent of influent raw water turbidity, within this range of values.
- While this indicates that the filter material does indeed acheive a significant level of colloidal removal at about 60% , we would like this value to be higher, around 90%.
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Figure 3: Raw Water and Effluent Turbidity vs. time for a flow rate of 200 m/day
This graph Figure 3 indicates that the higher flow rate of 200 m/day increased the effluent turbidity to about 2 NTU. However, given the amount of planned space saved by the increased flow rate, this level of performance loss may be acceptable.
Figure 4: PC* vs. time for a flow rate of 200 m/day
As expected, Figure 4 shows that the percent colloid removal decreased with the increase in flow rate. At 200 m/day, only about 40% of colloids are removed. Again, we would optimally like to achieve a percent colloid removal of about 90%, therefore, we will investigate foam with a higher ppi (smaller pore size).
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