Screw Sludge Dehydrator

The screw press sludge dewatering machine is an energy-efficient and compact continuous sludge dewatering equipment. Its core structure consists of fixed rings, moving rings, a screw shaft, and a drive system. It pushes sludge forward through the rotation of the screw shaft, and at the same time realizes extrusion dewatering by utilizing the gap between the fixed rings and moving rings.
This equipment is suitable for sludge dewatering in municipal sewage and industrial wastewater (printing and dyeing, electroplating, food processing, etc.), especially for treating low-concentration and high-viscosity sludge (moisture content 99.5%-98%). It does not require the construction of a thickening tank and can directly treat sludge from biochemical tanks. With the characteristics of small floor space, high degree of automation, low risk of clogging, and low operation and maintenance costs, it is the preferred dewatering equipment for small and medium-sized sewage treatment stations and decentralized water treatment projects.

The core working principle of the screw press sludge dewatering machine is the dual effect of filtration thickening + screw extrusion. The entire process is continuous and does not require high pressure, which is specifically divided into three stages:
1.Mixing and Flocculation Stage: The sludge to be dewatered is fully stirred with flocculant (PAM) in the mixing tank, and sludge particles form flocs to achieve preliminary solid-liquid separation, laying the foundation for subsequent dewatering. This stage can improve the dewatering performance of sludge and avoid sludge clogging the filter gaps.
2.Thickening and Filtration Stage: The flocculated sludge is pushed to the thickening section by the screw shaft. The gap (0.5-2mm) between the fixed rings and moving rings traps sludge flocs, and free water is discharged through the filter gaps under the action of gravity. The moisture content of the sludge decreases from 99.5%-98% to 90%-85%, completing preliminary thickening.
3.Screw Extrusion Stage: The thickened sludge enters the extrusion section. The pitch of the screw shaft gradually decreases and the shaft diameter gradually increases, forming an increasing extrusion force. At the same time, the moving rings rotate with the screw shaft to continuously clean the filter gaps and prevent clogging. Under the action of extrusion force, capillary water in the sludge is forced out, and finally, sludge cakes with stable moisture content are formed and discharged through the sludge discharge port.
The entire process does not require a high-pressure pump and completes dewatering by relying on the mechanical thrust of the screw shaft, with low operating noise and energy consumption.

Screw press sludge dewatering machines can be divided into multiple series according to processing capacity, screw shaft diameter, and structural form, with core parameters and characteristics as follows:
1. Classification by Screw Shaft Diameter (Core Specification)
The screw shaft diameter directly determines the equipment processing capacity. The mainstream specifications and applicable scenarios are as follows:

• φ132 Type: Small-sized equipment with a single-unit processing capacity of 0.5-2m³/h sludge, suitable for laboratories and small sewage treatment stations (daily sewage treatment capacity ＜500m³);
• φ201 Type: Medium-sized equipment with a single-unit processing capacity of 2-8m³/h sludge, suitable for township sewage treatment stations and food processing plants (daily sewage treatment capacity 500-5000m³);
• φ301 Type: Medium-to-large-sized equipment with a single-unit processing capacity of 8-15m³/h sludge, suitable for medium-sized municipal sewage treatment stations and printing and dyeing factories (daily sewage treatment capacity 5000-20000m³);
• φ401 Type: Large-sized equipment with a single-unit processing capacity of 15-30m³/h sludge, suitable for large-scale industrial wastewater treatment stations and branch plants of municipal sewage treatment plants.

2. Classification by Structural Form

• Standard Screw Press Sludge Dewatering Machine: Integrates a mixing tank, thickening section, and extrusion section into one, with a compact structure and a floor space of ≤5m², suitable for projects with limited site space;
• Split-Type Screw Press Sludge Dewatering Machine: The mixing tank is separated from the main machine, and the flocculation reaction time can be adjusted according to working conditions, suitable for treating high-viscosity sludge (such as printing and dyeing sludge and pharmaceutical sludge);
• Explosion-Proof Screw Press Sludge Dewatering Machine: The motor and electrical system adopt explosion-proof design, suitable for sludge dewatering in flammable and explosive working conditions such as petrochemical and coal chemical industries.

3. Classification by Degree of Automation

• Semi-Automatic Type: Manually controls the flocculant dosage and starts/stops the equipment regularly, suitable for small-scale intermittent operation projects;
• Fully Automatic Type: Integrates an online sludge concentration detector and a PLC control system, which can automatically adjust the flocculant dosage and equipment operating parameters according to the incoming water concentration, realizing unattended operation, suitable for large-scale continuous production.

Selection Notes

When treating high-viscosity sludge (such as printing and dyeing sludge), the split-type structure is preferred to extend the flocculation reaction time;

When the sludge has a high sand content, a pre-installed sand-water separator should be added to avoid sand particles wearing the screw shaft and rings;

For explosion-proof working conditions, equipment with an explosion-proof grade of Ex d II BT4 or above should be selected.

With the characteristics of compactness, low energy consumption, and anti-clogging, the screw press sludge dewatering machine is widely used in municipal and industrial sludge dewatering fields, with core scenarios as follows:

1. Core Product Features

2. Practical Application Effects