SF. 4 - 



- \ 



V ZSV = 2.48 FT/HR 







Vv >v ZSV = 0.71 FT/HR 



^^- HOT SPOT 









^- COMPOSITE 



— 



\zSV = 1.42 FT/HR 

 t 1 1 1 1 



^^ CAPPING 



1 1 1 1 







TIME, HR 



Figure 3. Comparison of the interface depth versus time 



too high for those concentrations as a result of "bridging" against the column 

 walls. The bridging of the particles at those concentrations is believed to 

 result from using a small-diameter column. The settling of the solids inter- 

 face increases because the water that is displaced by the subsidence of solids 

 encounters less resistance flowing upward along the wall than the more diffi- 

 cult route between particles, as outlined in Montgomery (1978). The ADDAMS 

 generated a plot showing a linear relationship between the logarithm of the 

 zone velocities (feet per hour) and the slurry concentration (grams per litre) 

 (Figure 4) . An exponential equation was developed to determine the zone 

 velocity at any given concentration. 



29. The ADDAMS was also used to generate a solids loading curve using 

 the zone settling curve to show the relationship between solids loading, S 

 (pounds/hour-square foot) and solids concentration, C (pounds/cubic foot) 

 (Figure 5). 



15 



