With the rapid development of urbanization and industrialization, water pollution has become a global concern. Sewage and wastewater treatment is no longer just a regulatory requirement, but also an inevitable requirement for environmental protection and sustainable development. Therefore, it is crucial to choose the right treatment technology, especially the technology that strikes a balance between high performance and energy saving. Among the many wastewater treatment technologies, the decanter centrifuge (also known as the sedimentation centrifuge) is the first choice for modern sewage treatment facilities because it not only can efficiently separate solids and liquids, but also consumes significantly less energy than traditional systems.
What is a Decanter centrifuge?
1 Working Principle
A horizontal screw centrifuge is a high-speed rotating machine that uses centrifugal force to separate solid particles from liquid. It mainly consists of the following components:
Drum: It is cylindrical or conical and rotates at high speed to generate centrifugal force.
Screw conveyor (spiral scroll): It rotates at a slightly different speed from the drum and transports solid particles to the discharge end.
Feed pipe: Introduces the sludge mixture into the machine.
Discharge port: Separate outlets for clarified liquid and dehydrated solids.
After the solid-liquid mixture (sludge) enters the drum, it is quickly subjected to a centrifugal force thousands of times stronger than gravity. The heavier solid particles settle on the inner wall of the drum, while the clarified liquid (concentrated liquid) moves to the center and is discharged through the overflow port. The screw conveyor continuously transports the solid filter cake to the conical end and then discharges.
2 Types of Decanter Centrifuges
While the basic design is similar, there are several specialized types:
Two-phase centrifuges: Separate solids and one liquid phase.
Three-phase centrifuges: Separate solids from two immiscible liquids.
Why sludge dewatering is important
1 Volume reduction
Raw sludge contains up to 95-99% water. Dewatering significantly reduces volume and weight, making transportation and disposal more cost-effective.
2 Cost savings
Reduced sludge water content means:
Less energy required for further drying
Reduced landfill costs
Reduced transportation costs
3 Compliance and environmental impact
Proper sludge handling ensures:
Compliance with environmental regulations
Prevents leachate contamination
Reduces greenhouse gas emissions
Horizontal spiral centrifuges can efficiently achieve these goals, making them an integral part of wastewater treatment equipment.
Energy efficiency of decanter centrifuges
Lower energy consumption,Horizontal screw centrifuges consume significantly less energy. This is due to the optimized bowl design, which minimizes friction and consumes low power.
Efficient separation capabilities
1 High solids recovery
Horizontal spiral centrifuges can recover more than 95% of solids from sludge, resulting in:
Cleaner effluent
Reduce downstream treatment
Better environmental performance
2 Continuously dry sludge cake
The centrifuge produces a sludge cake with a dry solids content of 20-35%, depending on the feed material. This is much drier than the sludge cake produced by other technologies, resulting in reduced volume and improved ease of handling.
3 Handling difficult sludge
Whether the sludge is oily, fibrous or contains chemical flocculants, the horizontal spiral centrifuge can handle a wide range of sludge concentrations without frequent adjustments or plugging.
Real-world case studies
1 Wastewater treatment plant
Problem: Ageing belt filter press with high maintenance costs.
Solution: Replacement with horizontal screw centrifuge.
Results:
30% increase in dewatered solids production
40% reduction in energy consumption
50% reduction in sludge disposal
2 Food Processing Plant
Demand: Improve vegetable processing wastewater treatment.
Implementation: Replace traditional sedimentation tanks and belt filter presses.
Results:
Recover 90% of water resources and reuse
Reduce energy consumption by 45%
In a world where efficiency, sustainability, and regulatory compliance are critical, the horizontal screw centrifuge has proven to be a powerful tool in the sewage treatment sector. Its energy-saving capabilities, combined with high separation efficiency and operational advantages, make it an increasingly popular choice among municipalities and industries alike.
By reducing sludge volume, lowering operational costs, and producing cleaner effluent, this technology not only meets today’s wastewater treatment challenges but also aligns perfectly with future sustainability goals. Whether it’s for a sprawling municipal facility or a compact industrial plant, the horizontal screw centrifuge offers a smart, long-term investment in both performance and planet.
