UFC 3-280-04
17 DEC 2003
8-3.5.12 To determine approximate run time between filter changes, use the following
equation:
Run time [days] = solids loading, 250 mm filter number of 250-mm filters / feed suspended
solids concentration 1440 min./day
8-3.6
Support Facility Requirements. Based on the initial selection of equipment,
utility requirements for ventilation, power, water, air, telephone, and other utilities can be
determined. Although some of these calculations may be needed for the entire treat-
ment facility, incremental calculations that apply specifically to equipment or facilities
required for the filter operation may be necessary. Generally, for the package systems
addressed, the manufacturer will supply required information. Additional calculations
and design data will need to be assembled for a variety of equipment to support the fil-
tration system. These items include but are not limited to:
Pumps. Head loss calculations and power requirements for backwash water
supply pumps, spent backwash water pumps to transfer filtrate back to the head of the
plant, settled sludge removal pumps from the spent backwash holding basin, filter feed
pumps.
Air Supply. For valve operations and air scour if provided.
Tankage. Filter feed pump tank, filtered water storage, clean backwash water
storage, spent backwash water storage.
Controls. Filter head loss rate, backwash sequence, flow rate, interlocks,
alarms.
Chemical Feed. Chemical storage, mixing, day tank, and chemical feed
pump sizing, chemical selection, feed concentration, and physical storage concerns.
Access. Issues related to sample collection, monitoring, and maintenance of
equipment.
Calculations. In addition to utility requirements, additional design and
calculations related to architectural and structural components will be required. These
types of calculations are application specific, and therefore no specific calculations are
provided.
8-10
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