Handex Insights

What is Sludge Dewatering?

Written by Jim Caccese | April 6, 2021


When you think of dewatering these three questions might pop into your head; what is the purpose of dewatering? What is the dewatering process? And why is dewatering necessary? Continue reading for these answers and more.

What is the Purpose of Dewatering?

Sludge dewatering separates sludge into liquids and solids for waste minimization. There are various technologies for sludge dewatering, including plate & frame and belt filter presses, centrifuging, screw pressing and geomembranes. In addition to these, there are other options available.

It is important to note that dewatering is not intended to treat the sludge or liquid, it only separates the solid and liquid components so that it is easier and more cost-effective to handle the separate phases for final disposal. Once the sludge has been dewatered, both the solid and liquid components may contain contaminates that will need to be treated separately.

What is the Dewatering Process?

Before the dewatering process can begin, sludge has to be conditioned through either mineral chemical such as iron salts and lime. Or organic chemicals such as coagulants and flocculants. After conditioning the sludge, it is then thickened through either flotation, gravity belt, a thickening drum/screw drum, or a Centrifuge.

Once the conditioning step is complete it is now time to analyze which dewatering technique is appropriate. The choice of a sludge treatment method is dependent on several factors including the characteristics, volume, timing and the available disposal options. The three most common dewatering options are belt filter, Centrifuge, and frame filter press. To find out which dewatering method is right for you, check out our more in-depth explanation of the three methods.

Why is Dewatering Necessary?

The two main purposes of sludge dewatering is for waste minimization and to achieve overall cost efficiency for disposal. Additionally, stabilized sludge can be handled more safely and can reduce health hazards. Some sludges actually have a great beneficial reuse and can be land applied. Generally, both the public and private sectors are required to dispose of sludge in a manner that is approved by regulatory agencies and are in line with their own organizational requirements and environmentally safe.

Sludge dewatering is typically focused on reducing the weight and volume of the sludge so that disposal costs - including transportation - are kept to a minimum. Water removal is the primary means of volume reduction before sludge waste can be treated or disposed of in the most economical manner.

Choosing the Optimal Technology?

As we mentioned before the choice of a sludge treatment method is dependent on several factors including the characteristics, volume, timing and the available disposal options.

When searching for dewatering services, it is important to look for a partner who can offer a comprehensive suite of dewatering services and apply the right technology for your specific issues to provide the most cost effective solution.

About Handex

Handex is a provider of Pumping, Dredging, Sludge Dewatering and Treatment of industrial and process wastes. Our staff includes experienced Project Managers, Engineers, Operators, Technicians, Fabricators, Scientists, Mechanics, and Health and Safety Professionals. Our objective is to meet and exceed client expectations while providing quality, safe and cost-effective services. In some cases, our clients find that the value of the materials returned to the plant pays partially for the cost of the sludge dewatering service.

For more information about dewatering, request a free quote today, or contact us here.

Originally published Sep 15, 2016, updated April 6, 2021



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Written by Jim Caccese
Jim Caccese is a senior client relationship manager for Handex. He is committed to providing the highest level of safe and quality service to our clients. Jim has extensive experience in the environmental industry including consulting, operations, construction, management, research/development and sales.

Topics: Dewatering