Filter Presses

In a filter press, dewatering is brought about through the use of high pressure to force the water out of the sludge. Benefits of the filter press are high sludge cake concentration, filtrate clarity and high solids capture. Instead, the system is characterized through high mechanical complexity, high labour costs, high chemical costs, and limited cloth life. The two most hugely used filter presses are the fixed-volume and the variable-volume recessed-plate kinds. The fixed-volume filter press consists of a series of rectangular plates which are supported face to face within a vertical position, along with a filter cloth hung over each plate. The conditioned sludge is pumped within the space among the plates and subjected to high pressure for 1 to 3 hours, so which the liquid is forced by the cloth and plate outlet ports. The plates are then separated and the sludge is erased. The variable-volume recessed-plate filter press is same to the fixed-volume type except in which a rubber diaphragm is placed among the plates to help reduce cake volume during compression.