Page 335 - Statistics for Environmental Engineers

L1592_frame_C38 Page 344 Tuesday, December 18, 2001 3:21 PM

10 13.3 20.0 1.8 7.43 20.55 3.0
11 13.3 26.7 3.0 6.06 12.20 3.7
12 13.3 26.7 3.0 6.14 12.56 3.6
13 13.3 26.7 0.6 6.36 11.94 6.9
14 13.3 26.7 0.6 5.40 10.57 6.9
15 13.3 26.7 1.8 6.18 11.80 5.0
16 13.3 26.7 1.8 6.26 12.12 4.0
Source: Adapted from Deitz J. D. and T. M. Keinath, J. WPCF, 56, 344–350.
(Original values have been rounded.)
38.4 Final Clarification. The influence of three factors on clarification of activated sludge effluent
was investigated in 36 runs. Three runs failed because of overloading. The factors were solids
retention time = SRT, hydraulic retention time = HRT, and overflow rate (OFR). Interpret the
data.

SRT HRT OFR Eff TSS SRT HRT OFR Eff TSS
Run (d) (h) (m/d) (mg/L) Run (d) (h) (m/d) (mg/L)
1 8 12 32.6 48 19 5 12 16.4 18
2 8 12 32.6 60 20 5 12 8.2 15
3 8 12 24.5 55 21 5 8 40.8 47
4 8 12 16.4 36 22 5 8 24.5 41
5 8 12 8.2 45 23 5 8 8.2 57
6 8 8 57.0 64 24 5 4 40.8 39
7 8 8 40.8 55 25 5 4 24.5 41
8 8 8 24.5 30 26 5 4 8.2 43
9 8 8 8.2 16 27 2 12 16.4 19
10 8 8 8.2 45 28 2 12 16.4 36
11 8 4 57.0 37 29 2 12 8.2 23
12 8 4 40.8 21 30 2 8 40.8 26
13 8 4 40.8 14 31 2 8 40.8 15
14 8 4 24.5 4 32 2 8 24.5 17
15 8 4 8.2 11 33 2 8 8.2 14
16 5 12 32.6 20 34 2 4 40.8 39
17 5 12 24.5 28 35 2 4 24.5 43
18 5 12 24.5 12 36 2 4 8.2 48
Source: Cashion B. S. and T. M. Keinath, J. WPCF, 55, 1331–1338.

© 2002 By CRC Press LLC