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What Is Sludge Dewatering?
News & Media

What Is Sludge Dewatering?

Sludge dewatering is a process used in wastewater treatment and various industrial applications to reduce the moisture content of sludge. The primary purpose of sludge dewatering is to separate liquid from the solid components of the sludge, reducing its volume and weight. The dewatered solid is easier and more cost-effective to transport, store and further process.

Several Methods for Sludge Dewatering

Here are some common methods used in sludge dewatering:

1. Mechanical Dewatering:

Belt Filter Press: Sludge is squeezed between two permeable belts to remove water.

Screw Press: Sludge is compressed and dewatered by a rotating screw within a cylindrical screen.

Plate Filter Press: Sludge is passed through a series of filter plates and frames to separate water.

Decanter Centrifuge: A centrifuge rotates the sludge at high speeds to separate solids from liquids.

2. Thermal Dewatering:

This process involves applying heat to the sludge to promote evaporation and water removal.

3. Vacuum Filtration:

A vacuum is applied to a porous medium, such as a filter cloth, to draw out water from the sludge.

4. Gravity Thickening:

In this method, sludge is allowed to settle in a tank, and gravity helps in the separation of water from solids. The thickened sludge is then easier to dewater further using other methods.

At Tianzhong Machinery, we offer screw press dewatering machine and multi disc screw press to meet different needs for sludge dewatering.

Main Equipment Used for Sludge Dewatering

Below let’s overview these two kinds of mechanical dewatering equipment, the features and the sludge dewatering process.

Multi disc Screw Press

Multi disc screw press features fixed and movable rings stacked together with a central screw shaft forming the filtration unit. It achieves dewatering through gravity concentration and internal pressure created as sludge progresses against backpressure plates. Filtrate filters out through the gaps between fixed and movable rings, while dewatered sludge cakes are discharged from the end of the dewatering section.


  1. Self-cleaning, preventing clogging.
  2. Suitable for dewatering low-concentration sludge.
  3. Low rotational speed, energy-efficient, low noise and odor.
  4. Automatic operation, with 24/7 unmanned operation.
Mutil Disks
Multi Plates
Sludge Screw Press for Sale
Multic Disc Screw Press

Screw Press Dewatering Machine

The screw press dewatering is a process that applies pressure to sludge using a slowly rotating screw within a cylindrical screen. As the screw rotates, the material is push forward from the inlet to the outlet. The screw’s diameter gradually increases, reducing the volume between the screw blades. This compression separates the liquid from the solid. The liquid is squeezed out through the screen; while the solid is retained in the screen and pushed towards the outlet. Here are some key features and benefits of this equipment:


  1. Continuous Operation: Screw presses are capable of continuous operation, which means they can process sludge continuously without the need for frequent start-stop cycles.
  2. High Solids Content: They are highly efficient at removing water from sludge.The water content of the dewatered sludge cake is about 60%-80%.
  3. Low Energy Consumption: Screw presses generally consume less energy compared to other dewatering methods, making them cost-effective in the long run.
  4. Low Maintenance: These machines are relatively easy to maintain and have fewer moving parts, reducing the risk of breakdowns.

When choosing sludge dewatering equipment, you need to consider factors such as the scale of the wastewater treatment plant, sludge characteristics, desired water content of the dewatered cake, your budget, and more. Welcome to contact us for more details!

Screw Press Juice Extractor
Screw Press Machine
Reducing Screw
Reducing Screw


In conclusion, sludge dewatering aims at reducing the moisture content of sludge for easier handling and disposal. Tianzhong Machinery offers two kind of dewatering equipment for sludge, the multi-disc screw press and screw press dewatering machine. If you have any further questions about sludge dewatering, please feel free to contact us. Our team of experts is ready to assist you in finding the best solution for your dewatering needs.