Page 452 - Water and wastewater engineering

GRANULAR FILTRATION 11-25

A B C D
1 Example 11-5
2 Filter box dimensions for Ottawa Island
3
4
3
5 Q 18,400 m /d
max
3
6 Filtration rate 216 m /d − m 2
7 Number of filters 3
8
9 Area = 28.4 m 2
10
11 Width per cell = 2.66 m
12
13 Width per box = 5.33 m
14
15 L = 5.33 m
16
17 L:W = 2 :1
18
19
20
21 Solver dialog box inputs
22
23 Target cell B11
24 Equal to min
25 By changing B11
26 Subject to the constraints
27 B11 < or = 6
28 B17 > or = 2
29 B17 < or = 4
FIGURE 11-9
Solver solution for length and width of filter box for Example 11-5 .

where d 1 diameter of lighter media, m
d 2 diameter of denser media, m
3
density of water, kg/m
3
1 density of medium with diameter d 1 , kg/m
3
2 density of medium with diameter d 2 , kg/m
GLUMRB (2003) specifies the following effective sizes and uniformity coefficients:
• For sand, E of 0.45–0.55 mm and U 1.65
• For anthracite coal as a monomedium, E of 0.45–0.55 mm and U 1.65.
• For anthracite coal as a cap, E of 0.8–1.2 mm and U 1.85.