MIL-HDBK-1005/9A
d) Vacuum Filtration. There are three commonly used
vacuum filtration units that may be considered: rotary drum,
rotary belt, and coil filters. A typical rotary drum filter
installation consists of a horizontal compartmented drum, which
supports the filter media on its outer surface. The drum is
rotated, partially submerged, in a tank containing the sludge. As
each section of the drum passes through the tank, a vacuum pulls
the liquid inward and the solids are retained as a thin cake on
the filter media covering the outer drum surface.
The belt vacuum filter represents a recent improvement
in continuous rotary vacuum filtration. Rather than being fixed
to the drum, the filter medium belt is wrapped around the face of
the drum. The belt leaves the drum at approximately the two
o'clock lock position and is transported over a roll and wash
system which serves three purposes: cake washing, medium washing,
and belt alignment (prior to its being placed back on the drum).
The coil filter is similar in many respects to the belt
filter except that metal coil springs are used in place of a
filter belt. The metal coil springs are constructed of stainless
steel and are arranged in two layers in corduroy fashion around
the drum face. The coils, having approximately 10 percent open
area, do not function as a filter medium, but as support for the
filter medium developed from sludge solids.
Vacuum filtration apparatus is a complex system that
includes the following components: sludge feeding and conditioning
components, vacuum pump and receiver, vacuum filter, and filtrate
pump.
3.10.8.4 Sludge Disposal. The toxic characteristics of oily
sludges are specific to the oily waste treatment facility where
they are generated. An increase in the types of these sludges is
expected to be classified as hazardous due to the adoption of the
more stringent TCLP method for sludge toxicity characterization.
Consequently, these sludges will require handling and disposal
under RCRA. The final disposal of these sludges must be in
accordance with the applicable State and Federal regulations.
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