The Importance of Sludge Dewatering

02 Feb 2021 | Family

While it’s not pretty, sludge is a significant part of many industrial processes. Dredging, sewer management, oil refinement, and more all result in some form of a sludge being produced. This solid and liquid mixture needs to be managed before filtration or disposal are carried out for a cost-effective and straightforward process. This process, referred to as sludge dewatering, is essential to waste management and wastewater processing for a variety of industries.

Keep reading to learn how sludge dewatering can help you, and your options for implementing it.

Sludge dewatering is the process of separating solids and liquids from each other. The solids are isolated and collected separately through a variety of techniques that allow them to be dried, pressed, or otherwise easier to manage. The residual wastewater can then also be processed by a filtration system or removed more easily through standard disposal methods like piping or drainage.

Sludge dewatering helps to simplify wastewater disposal and lower processing costs by making the sludge more easily manageable. When the sludge begins, it is often full of solids that are retaining moisture. This causes the material to be heavier in addition to being thicker, which makes it harder to move through piping or other efficient methods of transfer. As a result, it is more expensive to dispose of based on weight. When it is dewatered, the solids are minimized and compacted in a dry, lightweight form that can be processed through standard waste management. The liquid aspect of the sludge – the part that made the mixture heavier – is then handled as wastewater which can be recycled for use elsewhere.

Overall, the process lowers wastewater processing costs by minimizing the risk of damage to machines and pipes handling unknown sludge mixtures. It also makes waste disposal simpler and allows for the recycling of wastewater after the separation occurs, lowering costs.

Sludge Dewatering Techniques

Depending on the viscosity of the sludge being treated, the capacity required, the space available, and budget, there are a few different ways to dewater sludge.

Belt Filter

Belt filters are one of the less intense sludge dewatering techniques, relying on gravity dewatering for much of the process. This leads to higher water content in the final product, but these systems are also often cheaper.  Another option is the Interfil Vacuum Belt Filter that offers the additional vacuum to help suck the water content from the filter cake.  Reducing the water content similar to a frame filter but more automated and easier to manage.

A belt filter uses filtered belts that carry the sludge through a series of steps that allow water to drain from the sludge via gravity or vacuum. It also has ploughs that work the sludge to squeeze more water out, which falls through the belt again. This process is repeated 2-3 times until there are primarily solids leftover, which can then be pressed one last time before being removed at the end of the system.


Centrifuges offer a greater level of separation than belt presses, producing solid “cakes” with lower moisture content. They are space-efficient but can be more expensive to manage and louder in operation.

The centrifuge works by spinning a cylindrical bowl that holds the sludge. As it spins at high speed, the centrifugal force causes the wastewater and solid particles to separate based on density. This results in two separate wastes that can be managed separately, with wastewater being recycled and solids being disposed of.

Frame Filter

Frame filters come in two forms: high-pressure and low-pressure. High-pressure systems can produce lower moisture content because of the higher pressure in the chamber allows more solids to accumulate from the sludge.

A frame filter works by filling multiple chambers at once. These chambers are separated by filters that strain the sludge into separate water and solids as the pressure inside builds, draining the wastewater out of the bottom and forming cakes within the filters.

Finding Your Sludge Dewatering Solution

If you’re looking to lower waste management and wastewater processing costs, consider implementing a sludge dewatering system from Interfil. Offering a wide array of industrial filtration systems and wastewater management solutions, your business can benefit from almost 25 years of experience in the industry to help you find the perfect solution for you.

Read also:

All About the Dieselcraft OC50 Centrifuge

All About the Interfil 2000 Surface Oil Skimmer