Screw Sludge Dewatering Unit

The screw sludge dewatering unit is designed for the mechanical dewatering of thickened wastewater sludge after biological or physico-chemical treatment stages.

In simple terms:
while sludge remains liquid, it is a problem.
Once dewatered, it becomes a manageable by-product.

The equipment reduces moisture content, decreases sludge volume, and prepares it for disposal, transportation, or further processing.

This is a critical stage that directly affects the operational costs of wastewater treatment plants.

Without effective sludge dewatering, it is impossible to achieve stable and cost-efficient WWTP operation.

A screw sludge dewatering unit operates at low rotational speed — and that is precisely its advantage.

Before entering the unit, sludge undergoes preliminary thickening in a gravity thickener. This is mandatory, as the equipment is designed to process thickened sludge rather than raw liquid.

The process takes place in several stages:

1. Flocculation

The sludge enters a mixing chamber where it comes into contact with a flocculant.
Fine particles aggregate into stable flocs.

Proper flocculation is essential — without it, efficient dewatering cannot be achieved.

2. Gravity Drainage

The conditioned sludge is fed into a perforated cylindrical screen.
Free water begins to separate through the filtration gaps.

The process is gradual, without sudden loads or pressure spikes.

3. Compression

The screw rotates slowly, conveying the sludge toward the discharge end.
As it moves forward, compression progressively increases.

At the outlet, a “sludge plug” forms. This plug creates back pressure, ensuring additional mechanical compression.

The result is a dewatered sludge cake with reduced moisture content and significantly decreased volume.

That is how a screw sludge dewatering unit works:
gravity + controlled compression + properly selected chemistry.

No high-speed centrifuges.
No excessive energy consumption.
No mechanical shock loads.

• Low Energy Consumption

The slow rotational speed requires significantly less power compared to centrifuges or belt filter presses.

• Stable Dewatering Performance

The process is not sensitive to short-term fluctuations in sludge feed. Operation remains smooth and predictable.

• Low Noise and Vibration

The absence of high rotational speeds reduces dynamic loads and allows installation inside enclosed buildings.

• Reduced Flocculant Consumption

Optimized flocculation zones and extended contact time help lower chemical usage.

• Compact Design

The screw sludge dewatering unit can be easily integrated into existing wastewater treatment facilities without major reconstruction.