23 JULY 2003
supplies and to control power transformers that supply power to all other components of
the system having lower power requirements (i.e., 120 volt/one-phase/60 Hz).
2-9.3.2 Emergency Power. Because the operation of the filter press system is
primarily a batch operation, the need for emergency power depends on the overall
treatment system and related process system. Therefore, the need for emergency
power should be evaluated on the basis on the entire treatment scheme and not just on
for the dewatering system.
2-9.3.3 Air. Air is typically required for instrument controls (i.e., pneumatic controls),
sludge feed pumps (i.e., air diaphragm sludge pump), for core or air manifold blowing,
and for inflation of diaphragms for the variable-volume filter press. Air is typically
supplied at 690 kPa (100 psi) from the air compressor and should be dry and oil free. If
higher pressures are required, an air receiver tank and a pressure regulator should be
used in together with the air compressor. Additional design considerations for air
compressors and associated equipment are presented in Paragraph 2-4.8.
2-9.3.4 Water. Auxiliary water may be required for filter press operations, such as
chemical conditioning and preparing an acid wash solution, washing filter media, and
inflating the diaphragms for the variable-volume filter press. Specific requirements,
rates, and pressures at which auxiliary water will need to be supplied will be specific to
both application and equipment. A backflow preventor should be required for all utility
water sources to stop cross-contamination of clean water from sludge sources.
System Startup. System startup procedures and sequences of operation will
vary, depending upon the filter press application and type of equipment used. For
example, if the filter press requires sludge conditioning before startup of the pumps that
transfer sludge to the conditioning mixing tank, the conditioning chemical should be
prepared so that it can be added simultaneously with the raw sludge. In addition to
auxiliary systems, the filter press equipment will also have a specific sequence of
operation. Typical sequences of operation for fixed-volume and variable-volume filter
press systems are described in Subparagraphs 2-9.5.1 and 2-9.5.2, respectively. How-
ever, for specific types of equipment used, the manufacturers' or equipment suppliers'
startup procedures should be followed and incorporated with the use of other equip-
Sequence of Operation. The paragraphs that follow present typical
sequences of operation for both fixed-volume and variable-volume plate and frame filter
press systems. The sequences of operations provided are based on the assumptions
given for each of the systems described below. The sequence of operation used for
actual presses will be based on the type of filter press used and associated supporting
systems, such as conditioning, precoating, core blowing and air blowing manifolds, and
filter media wash (i.e., water wash or acid wash).
2-9.5.1 Fixed-Volume Press Operation. A typical sequence of operation for a fixed-
volume plate and frame filter press system is presented below. For the sequence
described, it is assumed that the system is semiautomatically controlled and that the