• Belt filter presses with integral sludge conditioner and rotary thickener
  • Manual or automatic filter presses with membrane squeeze option
  • Stainless steel frame and rollers for durability
  • Complete system with feed and wash pumps, air compressor, polymer system, and controls



A Belt Filter Press is a biosolids/sludge dewatering device that applies mechanical pressure to a chemically conditioned slurry, which is sandwiched between two tensioned porous belts, by passing those belts through a serpentine of decreasing diameter rollers. Water is then removed from the slurry and a non-liquid material is produced called cake.

Typically, a belt filter press receives a slurry ranging from 1-4% feed solids and produces a final product of 14-34% cake solids. Performance depends on the nature of the solids being processed.



  • Automatic Operation: Timer control to allow continuous operation for present period. No operator required during the operation except for preparation of a polymer solution.
  • Wide Application: Suitable for all types of sludge, irrespective of whether the sludge is organic or inorganic in nature.
  • Rotary Thickener: Patented thickener effectively concentrates the incoming conditioned slurry by removing excess water. Our thickener exhibits a dewatering capacity of more than 35-40% compared to conventional belt press.
  • Auto Tensioner and Alignment Setting: The belt press is equipped with a built-in automatic tension adjustment system and an alignment setting system.
  • Self-Cleaning Mechanism: The belt will be automatically sprayed with water so as to keep the belt clean at all times. Minimum water is required. When the spray nozzles are clogged, just turn the red button to clean out the obstruction.
  • Low Polymer Consumption: Minimum polymer is required to condition the sludge before dewatering.
  • Low Operation and Maintenance Cost: The belt press is constructed with a stainless steel structure and rollers. Low power is required to run the belt press.
  • Safety Shut-Off: The belt press is equipped with an emergency stop button and a safety alarm system.


Process Description

Process description

  1. Sludge Thickener. Normally the sludge is further concentrated by the gravity thickener to about 2% solid content before it is pumped to the belt press for dewatering.
  2. Sludge Conditioning. Polymer is injected into the thickened sludge in order to make larger flocks of sludge. The type of polymer to be used depends on the nature of the sludge.
  3. Rotary Thickener. The conditioned sludge is first fed to the rotary thickener of the belt press to remove the excessive free water quickly and facilitate further thickening of the sludge.
  4. Gravity Zone. When the thickened sludge leaves the rotary thickener, it reaches the first part of the roller which allows for further dewatering by gravity.
  5. Compression Zone. After the gravity dewatering section, the sludge is gradually carried into the press dewatering section. A thick sludge then passes into the shear dewatering section.
  6. High Pressure Shear Zone. When sludge enters the shear dewatering section, there are a number of S-type rollers to form the sludge cake by the shear force.
  7. Sludge Cake. The dewatered sludge normally has a water content of between 66-86%, depending on the type and nature of the sludge.


Napier-Reid sludge dewatering systems serve the following purposes:

  • Reducing volume, thus reducing storage and transportation costs.
  • Eliminating free liquids before landfill disposal.
  • Reducing fuel requirements if residuals are to be incinerated or dried.
  • Producing a material which will have sufficient void space and volatile solids for composting when blended with a bulking agent.
  • Avoiding the potential of biosolids pooling and runoff associated with liquid land application.
  • Optimizing subsequent processes such as thermal drying


Flow Chart


Flow Chart