Decanter Centrifuge for Sludge Dewatering and Thickening

A sludge centrifuge—specifically a decanter centrifuge—is one of the most advanced mechanical solutions for solid–liquid separation in modern wastewater treatment plants. Combining continuous operation, high throughput, and reliable performance, decanter centrifuges effectively reduce sludge volume and increase solids content by combining thickening and dewatering in a compact footprint. Whether used on primary, secondary, or mixed sludge streams, our decanter centrifuge systems deliver strong performance, energy savings, and long-term operational stability.

Key Features & Advantages of sludge centrifuge

• Continuous & automated operation: designed for 24/7 use with minimal intervention
• Dual-mode thickening and dewatering: able to operate in a “thickening mode” for moderate solids concentration or full dewatering mode for maximum dryness
• High solids discharge (cake dryness): typical outputs up to 25 %–35 % or more, depending on sludge type and conditioning
• Low energy consumption: optimized bowl geometry and differential speed control reduce power usage
• Integrated polymer system compatibility: built to pair with advanced polymer dosing, mixing, and aging setups
• Robust wear resistance: critical zones protected with abrasion-resistant materials
• Compact footprint & modular design: easy integration into existing plants
• Ease of maintenance & serviceability: quick access to key components, modular spares

Sludge Centrifuge Working Principle

Separation takes place in a horizontal cylindrical bowl equipped with a screw conveyor.
The feed enters the bowl through a stationary inlet tube and is accelerated smoothly by an inlet distributor. The centrifugal force that results from the rotation then causes sedimentation of the solids on the wall of the bowl.
The conveyor rotates in the same direction as the bowl, but slightly slower, thus moving the solids towards the conical end of the bowl. The cake leaves the bowl through the solids discharge openings into the casing. Separation takes place throughout the entire length of the cylindrical part of the bowl, and the clarified liquid leaves the bowl by flowing over adjustable overflow dams into the casing.

Sludge Centrifuge Applications

• Municipal wastewater treatment plants (primary and waste activated sludge)
• Industrial effluents (food & beverage, chemical, pharmaceutical)
• Sludge pre-thickening before anaerobic digestion
• Sludge dewatering for disposal, incineration, or land application
• Dewatering of mixed sludge (primary + secondary) or digested sludge

Modern sludge centrifuges help meet global standards for efficient biosolids processing and reuse. For additional technical guidance, see the U.S. EPA’s biosolids resources and the Water Environment Federation’s biosolids overview.

Typical Performance Ranges

Sludge Type	Feed Solids (% TS)	Expected Cake Solids (% TS)	Recovery / Efficiency
Primary sludge	4–8 %	25–40 %	> 90 %
Waste Activated Sludge (WAS)	1–4 %	16–25 %	> 85 %
Mixed Sludge / Digested	2–4 %	22–32 %	> 90 %

Actual performance depends on sludge character, polymer conditioning, sludge centrifuge configuration, and control optimization.

Design & Optimization Considerations

• Bowl geometry & pond depth: influences residence time, separation zone and liquid retention
• Differential speed control: adjusting scroll speed vs bowl speed allows fine tuning between cake dryness and throughput
• Polymer injection strategy: optimal polymer mix, aging, and gentle mixing are critical
• Automation & control systems: torque feedback, alarms, and PAC (process automation control) enhance performance
• Maintenance planning: service access, wear replacement strategy, balance checks

Typical process flow of sludge dewatering

Technical Parameters

Designation	Bowl ID (mm)	Bowl speed (rpm)	Primary motor (Kw)	Start method	Weight (Kgs)
SSC16*	160	6000	4	VFD	800
SSC20*	200	5500	5.5	VFD	900
SSC25*	250	4800	7.5	VFD	1000
SSC30*	300	4200	11	VFD	1600
SSC35*	355	4000	18.5	VFD	2200
SSC40*	400	3650	22	VFD	2500
SSC45*	450	3200	37	VFD	3000
SSC50*	500	3000	45	VFD	4000
SSC53*	530	2900	55	VFD	5000
SSC58*	580	2780	75	VFD	6500
SSC65*	650	2500	75	VFD	7000
SSC76*	760	2250	90	VFD	8500