4 Common Sludge Dewatering Methods and their Pros and Cons

Do you intend to cut down your sludge or waste disposal and transportation costs? Then sludge dewatering techniques are a perfect solution for such needs. These techniques cut your waste handling costs. This post highlights the importance of sludge dewatering, the technologies used, and their pros and cons.

Why Dewater Your Sludge?

Sludge dewatering methods help you to cut down the liquid volume from the slurry sludge. The technologies reduce water in sludge by an estimated 80%. The dewatering reduces waste disposal and transportation costs, while also allowing you to comply with the waste disposal regulatory measures.

Freshwater is scarce, and only a measly 3% of the earth’s water reserves hold freshwater. By dewatering your sludge, you can get substitute non-fresh water for other activities such as tree farming and plant cooling. The non-fresh water cuts down the usage of freshwater for industrial purposes, thus making more freshwater available for human and animal consumption.

Here are the typical sludge dewatering methods used in industrial water treatment systems, and their pros and cons

The Centrifuge Dewatering Method

The centrifuge dewatering system makes use of high rotational speed equipment to separate waste components having varying density. This system operates on the principle that relies on buoyancy. In the centrifugal process, sludge components with a high density often drop to the bottom of the mix in a centrifuge. But the less dense materials stay suspended above the dense stuff. This system separates about 25% to 35% of the solid matter.

When is the Centrifuge Method Preferable?

This method is preferable, where fast processing is necessary. It’s also ideal where oil separation is the target and the quality of solids is of less concern. It’s thus ideal for dewatering slurry sludge with oil waste.

Plate and Frame Filter Press Technique

The plate and frame method uses recessed-chamber plates to separate the liquids from solids via filtration. In this method, the sludge gets pumped into a chamber lined with filter cloth linings, whose sides get squeezed together to create pressure that drives out the liquids from the sludge. After a complete pressing process the solid components known as the filter cake are dropped onto a horizontal conveyor. This method often gives you 40% to 70% solids by weight, and it can maximize solids recovery.

When is the Plate and Frame Filter Press Technique Preferable?

This method is preferable when seeking to get waste that is easy to transport. The generated filter cakes are stackable and easy to load and transport.

The Belt Filter Press

This process is akin to the plate and frame method, and the method uses pressure to squeeze out the liquid part of the sludge on a belt system. But it leaves in more moisture than the plate and frame method. The process gives a filter cake with approximately 18% to 25% solids by weight, and it’s also an efficient solids removal technique. It’s a continual process and thus ideal for significant waste volume processing.

When is the Belt Filter Press Method Preferable?

This technique is preferable in instances where a high moisture level is acceptable within the filter cake. This belt press system is common in municipal waste processing and other industries such as paper mills.

Takeaway:

Slurry sludge needs to get dewatered to reduce the liquid volume in it so that the remaining solid components can be transported with ease. The process also simplifies the waste treatment and disposal process while also fulfilling waste management and disposal regulations. The three common sludge dewatering methods operate in different ways, but they achieve the same goals.

The selection of the ideal method to use for your industrial or municipal waste treatment depends on the amount of sludge, the kind of materials in your sludge, the number of specific components in the sludge, and your goals and budget. By factoring most of these variables into your decision-making process, you can determine the perfect method to choose.

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