UFC 3-280-03
23 JULY 2003
3-4.1.2 Filter Press Volume. Based on the calculation of the "mass out" term of the
mass balance equation, the volumetric filter press capacity can be determined by the
following equation:
Cake volume produced per day = [(weight sludge dried solids per day) x (1 + fraction of condition-
ing chemical(s))] / [(% cake solids content) x (wet sludge cake density)]
Based on this volumetric calculation and the previously determined parame-
ters, the filter press can be sized based on the following calculation:
Filter press volume capacity per cycle = [(cake volume produced per day) x (hour per cycle)] /
[operating period (hour per day)]
Based on this capacity, a filter press should be selected from manufacturers'
information. The filter press selected and the accessories required can then be used to
determine utility requirements and subsequent sizing of other equipment.
3-4.2
Process Calculations. Process calculations include those that determine
design criteria and sizing of storage containers, chemical feed systems, and
accessories.
3-4.2.1 Storage Calculations. Several types of storage containers may be required
for filter presses, including tanks for storage of sludge, sludge conditioning, filter
precoat, filter media wash, acid wash, and sludge cake storage.
In general the sizing of these storage containers is either based on the
amount of detention required, or the frequency, duration, and quantity of material
required for the normal filter press operation.
3-4.2.1.1 Sludge Storage. The amount of storage required for the raw sludge is very
site specific and depends on requirements for equalizing flow and on sludge charac-
teristics, in addition to retention in a treatment process tank. A general rule provided by
the "Ten States Standards" is that a minimum of 4 days of storage shall be provided for
mechanical dewatering facilities unless other standby wet sludge facilities are available
(GLUMRB 1990). In general, the sludge storage capacity can be calculated by the
following equation:
Sludge storage volume requirement = (Volume of sludge produced per day) x (Number of days
required for storage)
3-4.2.1.2 Sludge Conditioning Storage. The size of the sludge conditioning tank will
be based on the amount of sludge to be processed and the conditioning chemicals
required. In general, vertical, cylindrical tanks equipped with a mixer and high and lower
level indication will be used for this. Based on the quantities of sludge and conditioning
chemicals required, a working volume should be calculated by the following equation:
Working volume of tank per cycle = (Volume of raw sludge per cycle + Volume of conditioning
chemicals required per cycle)
3-3
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