How Does a Screw Press Work?

Process Overview

Operating Steps

1. 1
   Polymer Conditioning

   Liquid sludge is mixed with polymer flocculant to form stable flocs. The polymer bridges fine particles into larger aggregates that can be mechanically separated.

2. 2
   Flocculation

   The conditioned sludge enters a flocculation chamber where gentle agitation allows flocs to mature and strengthen before entering the press.

3. 3
   Gravity Thickening Zone

   In the first section of the press, free water drains by gravity through the filtration gaps. The sludge begins to thicken as it moves along the screw.

4. 4
   Pressure Dewatering Zone

   As the screw pitch decreases and internal pressure increases, bound water is forced through the filtration gaps. The sludge is progressively compressed.

5. 5
   Cake Discharge

   The dewatered sludge cake is discharged at the end of the screw against a back-pressure plate. Cake dryness can be adjusted by modifying screw speed and back pressure.

6. 6
   Self-Cleaning

   Moving ring discs continuously clear the filtration gaps, preventing clogging and enabling stable long-term operation.