How Sludge Dewatering Screw Press Machines Work: Efficiency Meets Simplicity

Core Components & Operating Principle

A Sludge Dewatering screw press employs continuous mechanical pressure to separate liquids from solids. Key structural elements include:

• Screw Shaft: Hardened stainless steel (HRC 58-62) with 5° tapered pitch

• Screening Drum: Laser-cut 316L slots (0.25-1.5mm adjustable)

• Back Pressure Plate: Hydraulic-controlled (0-15 bar adjustable)

• Drive System: 3-phase 5.5kW motor with 87% IE4 efficiency

5-Stage Dewatering Process

1. Sludge Feeding

   • Polymer-conditioned sludge (0.5-1.5% DS) enters via progressive cavity pump

   • Initial gravity drainage removes 15-20% free water

2. Compression Zone

   • Screw rotation speed: 2-8 rpm (VFD controlled)

   • Increasing pitch creates axial pressure up to 12 bar

3. Shear Filtration

   • Solids travel through narrowing screen gaps

   • 90-95% solids capture rate achieved

4. Cake Discharge

   • 18-35% DS cake expelled through adjustable cone

   • Automatic blade trims cake thickness

5. Self-Cleaning

   • Reverse flushing nozzles (10 bar) prevent screen blinding

   • <5 mins/day manual intervention

Technical Advantages vs Alternatives

Typical Applications

• Municipal WWTPs handling 50-120 m³/day sludge

• Food processing plants with high-fat sludge (＞8% lipid content)

• Petrochemical sludge containing 5-15% hydrocarbons

Why Operators Choose Screw Press Tech
✅ 24/7 operation with ≤1% downtime
✅ 40% lower OPEX vs thermal dryers
✅ Handles 3-12% feed solids without pre-thickening