UFC 3-280-03
23 JULY 2003
Total cycle time, which includes all time required for sludge filtration, cake dis-
charge, and all other related time requirements (i.e., core blow).
Each data source used should be clearly identified within the design calcula-
tion and properly referenced with the date, title, or other pertinent information that will
identify the data source and its validity.
3-3.2
Reference Materials. Data and information from reference materials, other
than data from pre-engineering design and treatability studies, can be also used for filter
press design calculations. Reference materials consist of applicable codes, standards,
textbooks, standard tables, and manufacturers' catalogs and examples of
manufacturers' literature. Each source used should be properly referenced with the
date, title, issue, or other pertinent information.
3-3.3
Telephone Conversations Records. In addition to reference and design
data from the design analysis report, telephone conversations to equipment suppliers
and manufacturers and regulatory agencies may also be used for the design calcula-
tions.
3-4
COMPOSITION AND CONCENTRATION DEPENDENT CALCULATIONS.
Composition and concentration calculations provide the design basis for sizing the filter
press equipment and for related operation requirements. These types of calculations
can be categorized as pretreatment calculations and process calculations.
3-4.1
Pretreatment Calculations. Pretreatment calculations include those that are
required to provide the initial basis for sizing equipment and process conditions, such as
calculating mass balance and determining the required filter press volume.
3-4.1.1 Mass Balance Calculations. The mass balance calculations should be
based on previously determined hydraulic flow rates and solids concentrations for each
sludge generating stream to determine the total mass flow rate of sludge to be
dewatered. This calculation is based on the mass balance equation:
Mass out = Mass in.
The "mass out" term refers to the total solids to be removed by dewatering.
This term is determined from the "mass in" term, that is determined by the summation of
mass flow rates from each sludge generating unit as determined from multiplying the
sludge flow rate by solids concentration from each unit. The sludge generating units
may consist of clarifiers or biological treatment units, for example. To aid in these
calculations, a flow schematic showing both hydraulic flow rates, solid concentrations,
and mass flow rates to and from each process unit should be developed.
Based on the calculation of total daily mass of sludge generated , other
process calculations can determine the filter press volume and related sludge storage,
chemical feed systems, and other filter press accessories.
3-2
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