Wastewater treatment screw press SDE-315

for sludge dewatering

Overview
The SDE Series disc-type screw press integrates an inclined bowl made of moving and stationary discs acting as the filtration element, mounted in a robust casing that houses mechanical and safety components. The disc arrangement prevents clogging and enables straightforward cleaning. The screw features a gradually narrowing pitch to increase filtration at the inlet and compression toward the discharge.

Operation and Process
A separate tank at the bowl final section collects filtrate with higher solids content; this filtrate can be pumped back to the wastewater feed or thickening tank to maximize solids capture. An automatic, low-consumption washing system keeps the bowl clean while minimizing water use. The motor is driven via a frequency converter for smooth start/stop, speed and power control. PLC management and pneumatic pistons adjust compression automatically according to variable solids to ensure high dryness with low energy consumption. Main wetted parts are manufactured in AISI 304 stainless steel. Screw flights in the discharge zone are fitted with replaceable polyamide or castermid parts to sweep solids cleanly from the bowl inner wall.

Operating Principle
Sludge fed into the machine is advanced by the screw through the inclined disc bowl. Moving discs dewater the sludge while filtrate passes through the gaps between discs. As filtrate is removed, solids dryness increases; the solid cake is progressively pressed toward the discharge cone to reach maximum dryness. The bowl is cleaned automatically by periodic pressurised water sprays. The pressure cone adjusts automatically to changes in inlet solids to maintain optimal compression and dryness.

SDE Series — Specific Components

• Moving Disc: The paired moving and stationary discs prevent clogging of the filtration structure, allowing continuous dewatering and optional washing at chosen intervals. Components in contact with the product are AISI 304 stainless steel.
• Screw Conveyor: The screw is designed with a gradually narrowing pitch to compress sludge in three dimensions, minimizing centrate leakage while maximizing dryness. Screw is AISI 304 stainless steel; discharge flights use replaceable polyamide/castermid wear parts.

Shared Features and Components

• Automatic Solid Discharge Gap: Discharge gap adjusts automatically via discharge pressure to respond to variable solids rates, eliminating manual adjustments.
• Drive Unit: Low-speed drive reduces noise and energy consumption. The drive requires no external lubrication and is controlled by an inverter for speed and power management, with smooth start/stop.
• Control Panel: Electrical panel with HMI and PLC enables automatic and manual control of discharge pressure, screw speed, wash cycles and frequency, feed flow rate, and optional auxiliaries.

Product Models — Technical Specifications
Model: SDE-315
Installed motor power: 0.55 kW
Dimensions (L x W x H): 2480 x 820 x 1720 mm
Weight: 850 kg

Model: SDE-405
Installed motor power: 1.1 kW
Dimensions (L x W x H): 3100 x 880 x 2130 mm
Weight: 1500 kg

Product Features / Advantages

• Wide operating range to increase process flexibility and enable energy optimization.
• Continuous dewatering without clogging due to moving and stationary discs.
• Washing system allows continuous feed during cleaning without affecting cake moisture.
• Washing time and frequency adjustable via solenoid valves.
• Low energy consumption from low-speed operation; noise level under 60 dB.

Technical specifications

• Series name: SDE Series (Disc-type Screw Presses).
• Bowl: inclined, moving and stationary discs (AISI 304), filtration gaps between discs.
• Screw: gradually narrowing pitch, AISI 304 stainless steel, discharge flights with replaceable polyamide/castermid parts.
• Separate final-section tank for filtrate recirculation to feed or thickening tank.
• Automatic bowl washing with pressurised water; adjustable wash time and frequency.
• Motor drive: frequency converter/inverter for smooth start/stop, speed and power control.
• Control: PLC with HMI, pneumatic pistons for automatic compression adjustment to variable solids.
• Automatic solid discharge gap adjustment by discharge pressure for variable solids rates.
• Low-speed drive unit, no external lubrication required, noise level < 60 dB.
• Materials: AISI 304 stainless steel for main wetted parts.
• Models and key specs: see Product Models — Technical Specifications section above.