Sludge Dewatering Instrument
The filter press basically consists of a
number of chamber filter plates (also referred to as recessed filter
plate pack) mounted vertically on and between two sidebars or suspended
from an overhead support beam. A filter cloth is mounted over each of
the two faces of the filter plate. The cloth is joined at the feed eye
by an impervious sleeve or tube also known as a barrel neck.
Filter Press Feed Cycle:-
Step 1 : Sludge is fed into the filter press by a suitable pumping system and passes
through the feed eye of the succeeding plates along the length of the
plate pack until all chambers are full of slurry. This is known as the
fast fill portion of the filter cycle.
Step 2 : Flowing under pressure, the solid
particles begin to deposit on the surface of the filter cloth forming
the initial layer of filter cake referred to as the pre-coat. Once
applied, this pre-coat layer becomes the actual filtering medium.
Step 3 : As filtering continues the cake
thickness gradually increases, until the adjacent filter cake in each
chamber touch or bridge. At this point of the filter cycle, the
dewatering phase enters into final cake consolidation to achieve maximum
The filter cloths are woven
fabrics using monofilament or multifilament synthetic fibers or a
combination of both. The most commonly used materials are polypropylene,
polyester, and nylon. Filter cloths are primarily selected for
filtration, strength, and cake release properties.
Sludge Drying Bed
Sludge drying beds may be used for
dewatering sludge. Drying beds are confined, under drained and shallow
layers of sand over gravel on which wet sludge is distributed for
draining and air drying. Drying beds have proved satisfactory at most
small and medium-sized sewage treatment plants located in warm, dry