ABSTRACT
Solid/liquid separation occurs in a centrifuge as a result of rotating the liquid at high speeds to cause separation by gravity.
There are many types, but the most common centrifuge for dewatering sewage sludge is the solid bowl centrifuge. The solid bowl type has a rotating unit with a bowl and a conveyor. The unit has a conical section at one end that acts as a drainage device. The conveyor screw pushes the sludge solids to outlet ports and the cake to a discharge hopper.
The sludge slurry enters the rotating bowl through a feed pipe leading into the hollow shaft of the rotating screw conveyor. The sludge is distributed through ports into a pool inside the rotating bowl.
As the liquid sludge flows through the hollow shaft toward the overflow devices, the finer solids settle to the wall of the rotating bowl. The screw conveyor pushes the solids to the conical section where the solids are forced out of the water, and the water drains back into the pool.
