Page 363 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

318 Fundamentals of Water Treatment Unit Processes: Physical, Chemical, and Biological

pB Q Δh
ΔV
qB Q rB
B
Q
Q w

(a) (b)
FIGURE 11.18 Side baffled mixing basin. (a) Top view. (b) Side view.

TABLE 11.9
Design Data from Literature as Compiled by Haarhoff (1998, p. 143)
Facility Designation
B C
Flocculation Stage Flocculation Stage
Variable A #1 #2 #3 #1 #2 #3 D E F
3
Q (m =s) 0.283 0.500 0.500 0.500 0.116 0.116 0.016 0.010 0.100 1.00
1
G (s ) 40 70 35 20 50 35 25 50 50 50
Flocculation time (s) 1800 500 500 500 420 420 420 1000 1000 1000
n(channels) 20 22 18 14 23 17 14 18 18 18
Channel width, B (m) 0.763 2.590 3.170 4.070 0.450 0.62 0.770 0.288 0.944 2.86
Slot width ratio, p 0.33 0.21 0.31 0.36 1.51 1.50 1.56 0.52 0.50 0.52
Baffle overlap ratio, r 26.3 0.82 0.09 0.18 9.11 6.06 4.49 44.1 12.8 3.50
Water depth ratio, r 3.20 0.77 0.63 0.49 2.22 1.61 1.30 0.52 0.50 0.52
Channel velocity (m=s) 0.152 0.097 0.079 0.061 2.257 0.187 0.150 0.233 0.225 0.23
Time per turn (s) 95 24 29 38 19 26 32 59 59 59

TABLE 11.10
Full-Scale Baffled Flocculators in South Africa

Facility Designation
P6
Flocculation Stage
Variable P1 P2 P3 P4 P5 1 2 3
3
Q (m =s) 1.389 0.058 0.231 0.174 0.695 0.174 0.174 0.174
1
G (s )
Flocculation time (s) 630 279 576 619 331 76 244 115
n(channels) 19 29 43 26 17 6 17 7
Channel width, B (m) 2.000 0.370 0.900 1.175 1.400 0.680 0.870 1.174
Slot width ratio, p 1.000 1.000 1.000 1.000 0.98 1.000 1.000 1.000
Baffle overlap ratio, r 2.70 1.51 0.89 1.33 1.88 3.74 2.48 1.32
Water depth ratio, r 1.20 2.82 1.39 0.74 1.24 1.18 0.82 0.56
Channel velocity (m=s) 0.289 0.150 0.205 0.169 0.287 0.318 0.278 0.227
Time per turn (s) 33 10 13 24 19 13 14 18

Source: Haarhoff, J., Aqua, 47(3), 144, 1998.