90 ppi Flat Foam Sheet

After testing the filtering capacity of the 60 ppi foam, 90 ppi foam was tested in hopes of achieving a greater filtering capacity. Instead of testing the foam at constant flow rates, a ramp state was employed. Over the course of a 24 hour period, the flow rate through the foam sheet was gradually increased from 50 m/day to 250 m/day. This enables us to see whether or not a change in flow rate will effect the filtering capacity of the foam.

Figure 1 shows the raw water and effluent turbidity plotted as a function of flow rate (m/day). Before both the effluent turbidity and the raw water turbidity decrease at about 130 m/day it appears as though the effluent turbidity remains constant, regardless of flow rate.

Figure 1: Raw Water and Effluent Turbidity vs Flow Rate

At about 130 m/day the clay stock ran out for this experiment and raw water turbidity dropped. Though the data collected after this point does not help with the flow rate experiment, the PC* graph (Figure 2) remains relatively constant, suggesting that the filtering capacity of foam may be dependent on particle size and the foam will filter a given particle size regardless of the influent turbidity.

Figure 2: PC* vs Flow Rate