UFC 3-280-03
23 JULY 2003
Polymer = 1% of dried solids by weight
5-4.1.3.2 Biological Sludge.
a. Sludge Feed Characteristics.
Concentration of solids = 2%
Liquid sludge stream (includes influent and recycle streams) = 10,900 L/d (2 gpm)
Specific gravity = 1.0
b. Sludge Cake Characteristics.
Cake thickness = 32 mm (1.25 inches)
Wet cake density = 1120 kg/m3 (70 lb/ft3)
Minimum solids = 30%
c. Optimum Chemical Conditioning.
Lime (CaO) = 30 % of dried solids by weight
5-4.1.4 Fixed-volume recessed plate filter presses will be used for this example.
Typical ranges of design criteria for this type of filter press are presented in Paragraphs
2-3 and 2-4. For each type of sludge the following filter press information applies (see
Table 2-4).
5-4.1.4.1 Metal Hydroxide Sludge.
Cycle time
=
240 minutes (maximum 4 cycles per day)
Operating pressure
=
690 or 1550 kPa (100 or 225 psi)
5-4.1.4.2 Biological Sludge (Assume Industrial Type).
Cycle time
=
240 minutes (maximum 4 cycles per day)
Operating pressure
=
1550 kPa (225 psi)
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