TM 5-814-3/AFM 88-11, Volume III
Taking the natural logarithm of both sides of the equation results as follows:
0.75
ln 0.143 '
ln e
0.67
Q
0.75
&1.94 '
1.0
0.67
Q
0.67
Q
=
0.75/1.94;
0.67
Q
=
0.387;
0.67
(0.387)1.49;
Q
=
=
0.243 gpm/sq ft.
Required surface area can be computed by:
Flow Q
Surface Area '
Q
0.2 106 gpd
1,440 min/day
Surface area '
' 5,715; use 5,720 sq ft.
0.243 gpm/sq ft
D2
Since A '
4
D2
' 5,720;
4
0.5
5,720 4
D'
' 85.4; use 86 ft.
Therefore, the filter dimension sould be:
86 ft diameter 12 ft deep.
Plastic media manufacturers should be consulted to determine the exact proportions of filter media that pro-
vide for a minimum of 5,720 sq ft area and 12 ft depth.
C-8. Activated sludge, closed-loop reactor. (Refer to para 13-3.)
a. The following design criteria are for an oxidation ditch with horizontal-shaft rotor aerators, using a
single- channel, oval configuration and miltiple units in parallel, operated in an extended aeration mode with
nitrification.
Influent requirements:
Q, avg daily flow
= 1.0 mgd;
Q, peak flow
= 2.0 mgd;
BOD5
= 250 mg/b, typical of Army installations;
TSS
= 250 mg/b, typical of Army installations;
VSS
= 200 mg/b;
TKN
= 25 mg/b (all NH3 N);
P
= 8mg/b;
pH
= 6.5 to 8.5;
= 10EC;
Minimum temp
= 25EC.
Maximum temp
C-21
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