UFC 3-280-03
23 JULY 2003
Based on this working volume, the diameter and working height of the tank
should be determined. As a final step in determining the total height required for the
sludge storage container, height allowances should be provided in both the top and
bottom of this storage container to allow for high and low level indicators, as well as pro-
viding adequate freeboard to reduce the potential for overfilling, excess volume for
moderate and vigorous mixing, and any anticipated excess storage volume.
3-4.2.1.3 Precoat Storage. If required, the filter media will be precoated before the
filtration cycle and a storage tank must be provided. As a general rule of thumb, the tank
for the precoat system should be approximately one and one-half times the volumetric
capacity of the filter press.
3-4.2.1.4 Filter Media Wash Storage. The size of the filter media wash tank should be
based on the filter media washing requirements (duration and frequency) of the specific
filter press. The total volume required should be equal to the working capacity of the
tank calculated in Subparagraph 3-4.2.1.2.
3-4.2.1.5 Acid Wash Storage. The size of the acid wash storage depends on the acid
wash requirements (frequency and duration) of the specific application. The calculation
of the working capacity and total size required should follow the method described in
Subparagraph 3-4.2.1.2.
3-4.2.1.6 Sludge Cake Storage. The size of the sludge cake storage is very applica-
tion specific and will be based on the method of disposal or frequency of disposal. For
example, for an intermittently operated filter press unit, such as a unit that is operated
only once a week, only weekly up to monthly storage should be provided. However, for
continuously operated filter presses, such as those working several cycles per day, the
minimum storage capacity should be determined on the basis of the daily sludge cake
volume produced, with additional allowances for up to several days of storage for
contingencies related to transportation. Additional storage considerations are also
presented in Paragraph 2-4.8.
3-4.2.2 Chemical Feed Systems. Chemical feed systems for filter presses may
include those required for sludge conditioning, filter media precoating, and filter media
acid washing.
3-4.2.2.1 Conditioning Chemicals Feed Systems. The chemical feed dosages for
each type of conditioning chemical required is determined from treatability studies, and
are usually expressed as a percentage of the sludge on a dry weight basis. Based on
the mass flow rate of sludge to be generated and the percent of chemical dosage
required, the chemical dosage required can be determined from the following equation:
Chemical dosage per day = [Mass flow rate of sludge (weight per day)] x [Percent of chemical
required based on sludge dried solids]
3-4
Previous Page
