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Centrifugal thickening and dewatering of sewage sludge is a high speed process that uses the force from rapid rotation of a cylindrical bowl to separate wastewater solids from liquid. Centrifuges have been used in wastewater treatment since the 1930s. Thickening before digestion or dewatering reduces the tankage needed for digestion and storage by removing water. Dewatering removes more water and produces a drier material referred to as “cake” which varies in consistency from that of custard to moist soil.