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boss deformation, or plate warping that may indicate uneven pressure distribution or
plate deflection. These effects may eventually break the plate.
In addition to inspections for adverse wear, inspections for normal
maintenance should also be done. A summary of typical parameters and schedules for
periodic inspections for filter press equipment are presented in Table 2-10.
Safety Considerations. Inadvertent operation of the machinery while it is
being serviced is a primary hazard. Operation practices and precautions should be used
to prevent accidents.
2-9.7.1 Safety Features. The most common safety features on filter presses are
fixed guards and light curtains, which prevent injury by preventing access while plates
are being shifted. Detailed descriptions of these features are presented in
Subparagraphs 2-22.214.171.124 and 2-126.96.36.199, respectively.
2-9.7.2 Other Safety Considerations. Other areas of safety concern include protec-
tion from over-pressurization, proper chemical storage and handling, and adequate
ventilation. Additional information on these safety considerations are presented in EPA
(1986), WPCF (1983), and WEF (1992).
2-9.8.1 Heating. Heating requirements are a typical part of building design and
depend on site conditions (WPCF 1983). In general, the area around the press should
be heated to prevent any freezing. The temperature should be kept as constant as
possible because temperature can affect sludge dewatering characteristics. In addition
to adversely affecting the sludge, temperature can also affect the filter press equipment.
For example, in installations where rubber-coated steel plates are used, the filter press
and plate storage area should be maintained above 4 degrees C (40 degrees F) to
prevent thermal contraction and resulting damage.
2-9.8.2 Ventilation. The area of the filter press should be properly ventilated for
operator comfort, odor reduction, and protection from fumes (WEF 1992). The area
where the sludge is conditioned is the primary concern because odors and fumes are
generated there. For example, when sludge is conditioned with lime and ferric chloride,
the pH rises and significant amounts of ammonia may be generated and released in the
conditioning tank and filter press. The minimum ventilation rate should be six air
changes per hour for summer and three air changes per hour for winter (EPA 1986).
Fumes may also be emitted when the press is opened. Therefore, covering and
ventilating the area around the conditioning tank and filter press should be considered.
More detailed information on the design considerations for ventilation systems is
presented in WEF (1992).
DESIGN AND CONSTRUCTION PACKAGE. The design and construction
package for the filter press sludge dewatering system should include a design analysis,
drawings and plans, and project specifications (can be generated from guide