ApplicationNo. 06/055569 filed on 07/09/1979
US Classes:100/37, With separation from material of liquid expressed100/41, Forcing through constricted passage34/380With nondrying treating of material
ExaminersPrimary: Camby, John J.
Attorney, Agent or Firm
International ClassesB30B 9/12 (20060101)
B30B 9/02 (20060101)
B30B 9/26 (20060101)
C02F 11/12 (20060101)
B01D 36/02 (20060101)
B01D 36/00 (20060101)
B01D 29/13 (20060101)
B01D 29/25 (20060101)
AbstractSewage sludge is dewatered in a two-stage process. The first stage dewaters the sludge to a solids content above about 40 to 45 wt. %. The first zone comprises a cylindrical porous chamber with a centrally mounted screw conveyor which does not contact the porous wall of the chamber. The second stage further dewaters the sludge. The second stage applies pressure directly, as with a piston, to a stationary quantity of sludge which is in contact with a porous wall. The effectiveness of the second stage is increased through use of the first stage, which reduces the thixotropic nature of the sludge by dewatering it.