Description

DAGYEE Multi-Disc Screw Press sludge dewatering system – Continuous, Low-Energy Dewatering for Municipal and Industrial Wastewater

Product Overview

This is a multi-disc screw press sludge dewatering system—a continuous, low-energy machine that removes water from sludge and produces a solid cake suitable for disposal. It is designed for municipal wastewater treatment plants and a wide range of industrial applications including food processing, petrochemical, pulp & paper, and aquaculture.

Unlike centrifuges that use high-speed rotation or belt presses that rely on high-pressure rollers, the screw press uses a gentle, low-speed extrusion process. A central screw shaft rotates at just 2-5 RPM, pushing sludge through a gradually narrowing chamber. Water is squeezed out through the gaps between fixed and moving discs. The result is a stable, stackable cake with 15-22% dry solids content, reducing sludge volume by up to 80-90%.

Raw sewage sludge typically has a solids content of only 0.5-6%. After dewatering, the cake can be easily transported, landfilled, incinerated, or used for agricultural purposes. The system operates continuously, requires minimal operator attention, and consumes far less energy than centrifuges or belt presses.

Working Principle

The multi-disc screw press uses an innovative design of fixed and moving discs arranged around a central screw shaft. As the screw rotates at low speed, the discs gradually compress the sludge, extracting water through the gaps between discs.

The Process Flow:

Step 1: Sludge Conditioning
Sludge is pumped from a storage tank or thickener into a flocculation mixing tank. Polymer flocculant is added to condition the sludge, binding fine particles into larger, more stable flocs that are easier to dewater.

Step 2: Gravity Thickening
The conditioned sludge flows into the thickening zone of the screw press. Here, free water drains through the gaps between discs under gravity. This is the first stage of water removal.

Step 3: Mechanical Compression
As the screw rotates, the sludge is pushed along the shaft toward the discharge end. The screw shaft is tapered—the volume available to the sludge gradually decreases. This creates a gentle but effective pressing action that squeezes water out. The gaps between discs become progressively smaller, increasing the pressure on the sludge.

Step 4: Water Discharge
Water is forced out through the gaps between the fixed and moving discs. The filtrate drains into a collection tank and is returned to the treatment plant or discharged.

Step 5: Cake Discharge
The dewatered cake exits through the discharge opening at the end of the press. The cake typically contains 15-22% dry solids, depending on the sludge type and conditioning.

Step 6: Self-Cleaning
The relative movement between fixed and moving discs creates a continuous self-cleaning action that prevents clogging. This is a key advantage over Belt filter presses and centrifuges, which are more prone to blockages with fibrous or greasy sludges.

Key Features

Low-Speed Operation
The screw operates at just 2-5 RPM, resulting in quiet, energy-efficient operation. Power consumption is only 0.05-0.15 kWh per kilogram of dry solids processed. This is significantly lower than centrifuges and comparable to belt filter presses.

Self-Cleaning Disc Design
The relative movement between fixed and moving discs creates a self-cleaning action that prevents clogging. Even fibrous sludges, greasy sludges, and sludges with high oil content are handled effectively without blinding the media. This self-cleaning feature is particularly valuable for industrial applications where sludges often contain challenging materials.

Gradual Pressure Increase
The screw shaft is tapered, gradually reducing the volume available to the sludge as it moves through the press. This creates a gentle but effective pressing action that squeezes water out without high shear forces or mechanical damage.

Enclosed Design
The system is fully enclosed, containing odours and preventing splashing. This makes it suitable for indoor installation without additional ventilation infrastructure.

Minimal Wash Water
The multi-disc design requires only minimal wash water—typically 24-320 litres per hour continuous depending on model—compared to the high wash water consumption of belt filter presses.

Compact Footprint
The screw press is significantly more compact than belt filter presses and filter presses of equivalent capacity. This saves valuable plant space and reduces civil works costs.

PLC Automation
The system is fully automated, with PLC controls and an HMI touch screen. It can run continuously with minimal operator attention and can be integrated into plant SCADA systems.

Technical Specifications

Standard models are listed below. Custom configurations are available upon request.

• Wear part life extended 2-3 times vs. standard machines

• Handles sludge with up to 40% solids concentration

• Processes abrasive materials (sand, grit, mineral fines) without excessive wear

• Reduced maintenance downtime (annual servicing vs. quarterly for standard units)

• Lower total cost of ownership over 5-10 year period

• Suitable for applications where grit and sand are present in sludge

• No filter belts or cloths to replace (reduced consumable cost)

• Standby capability for critical applications

Model	DS Capacity (kg/h)		Sludge Capacity (m³/h)			Power (kW)	Dimensions (mm)			Operating Weight (kg)
	Min	Max	2g/L	10g/L	20g/L		L	W	H
DL101	3	5	1.5	0.6	0.25	0.2	1816	756	1040	290
DL131	6	10	3.0	1.2	0.5	0.36	1969	756	1040	315
DL202	18	30	9.0	3.6	1.5	1.1	2930	1257	1470	1110
DL301	30	50	15.0	6.0	2.5	0.74	3255	985	1600	1320
DL302	60	100	30.0	12.0	5.0	1.1	3455	1295	1600	2230
DL352	120	200	60.0	24.0	10.0	6.0	4420	2100	2250	4850
DL403	180	300	90.0	36.0	15.0	6.0	4420	2100	2250	4850

Note: Capacity and cake dryness depend on sludge characteristics, polymer type, and dosage. A sludge test is recommended for accurate sizing.

Materials:

• Screw and rings – Stainless 304 (316L available for corrosive stuff)

• Housing – Stainless 304

• Frame – Carbon steel with epoxy coating

Cake solids: 15% to 30% depending on your sludge and chemical

Temperature range: 0°C to 60°C

Voltage: We match yours – 380V/50Hz, 460V/60Hz, or others

Comparison with Traditional Equipment

Each technology has appropriate applications. The selection depends on specific site requirements including sludge characteristics, available labor, energy costs, and budget constraints.

What this means for you:

• Want the driest cake possible? Get a centrifuge. But budget for power and repairs.

• Have almost no budget upfront? Get a belt press. But plan for labor and water.

• Want the lowest total cost and least headache? Get our screw press.

Applications

Municipal Wastewater Treatment Plants
Dewatering of primary and secondary sludge from municipal WWTPs. Achieves 15-22% cake dryness, significantly reducing disposal costs and meeting landfill acceptance criteria.

Food and Beverage Processing
Sludge from dairy, meat, brewery, and vegetable processing operations. The self-cleaning design handles high-fibre and greasy sludges effectively.

Pulp and Paper
Dewatering of primary sludge and fibre-laden residuals from pulp mills and paper machines. Excellent fibre handling capability prevents clogging.

Petrochemical and Oil Refineries
Sludge with elevated oil and grease content. The self-cleaning disc design prevents blinding.

Aquaculture and Fish Farming
Sludge and solid waste from fish farms. The screw press handles fibrous and high-solids waste effectively.

Chemical Processing
Dewatering of chemical sludge and metal hydroxide sludges.

Leather and Textile Industries
Sludge from leather tanning and textile dyeing operations. The system handles challenging, high-organic-content sludges.

Conditioning: The Key to Effective Dewatering

Why Choose DAGYEE Multi-Disc Screw Press?

Contact Us

DAGYEE offers a comprehensive range of sludge dewatering solutions to meet the diverse needs of municipal and industrial wastewater treatment facilities. From the energy-saving volute screw press and the high-performance decanter centrifuge to the heavy-duty belt filter press and the rapid-deployment mobile system, each product is engineered with the latest technology to deliver reliable performance, low operating costs, and minimal environmental impact.

With decades of experience in solid-liquid separation, DAGYEE provides not only high-quality equipment but also full technical support—from sludge analysis and equipment sizing to installation supervision and after-sales service. Our team of engineers works closely with each customer to ensure the selected system matches site conditions, sludge characteristics, and performance requirements.

Whether you are planning a new wastewater treatment facility, upgrading existing dewatering equipment, or responding to an emergency situation, DAGYEE has the right solution for you. Contact us today to discuss your specific requirements and receive a customized proposal.

DAGYEE — Your Trusted Partner in Sludge Dewatering Solutions.

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