Pressing Onward: A Dewatering Blog

4 Things to Know When Sizing and Specifying Filter Presses

By Michael Stock



Selecting a filter press that will meet all of the dewatering needs of your facility can be daunting, whether you are installing a filter press for the first time or replacing old equipment. You might be wondering "Do I need a small or large capacity press? What type of filter cloths do I need?"

We want to help answer those questions. Read on to find out the 4 things that our dewatering experts recommend knowing when sizing and specifying filter presses.


#1 Slurry Composition

When you start thinking about what type of filter press your facility needs and gathering information, a good place to start is with your slurry composition. There are 3 key pieces of information you need to know about your slurry composition:

  1. Total Suspended Solids (TSS) - The TSS will impact what material filter plates and cloths are made of.
  2. Specific gravity - This number is used to calculate mass of dry solids per day to be dewatered.
  3. Temperature - Is used to select the appropriate construction materials for the filter press frame as well as determine operating parameters.


#2 Desired Slurry Input and Filter Cake Output

It is important to have an idea of how many gallons of slurry need to be dewatered and how many pounds of dry solids need to be produced per day by the filter press. The desired input and output will determine the size of the press and the number of filter plates.

If a small amount of slurry is being dewatered, a small capacity press with fewer filter plates might be a good choice. At the opposite end of the spectrum, if a large amount of slurry is being dewatered, a large capacity press with more filter plates will be required.

The amount of dry solids (or filter cakes) produced will impact the system you have in place for transporting and storing the filter cakes. There are a variety of options including dumpsters and drum disposal systems.


#3 Filter Cake Composition

Filter cake composition will impact a variety of things about your filter press including:

  • The types of filter cloths and filter plates used
  • If a sludge dryer is needed
  • If cloth washing is needed

There are 2 statistics you will need to know in regards to filter cake composition, total solids and wet cake density. If the filter cakes are very dense, extra structural support will need to be added to the press.


#4 Equipment Operating Hours

Knowing how many hours per day and how many days per week the press will operate is crucial. Operating hours determine how many times a press cycles and how long those cycles last. Most importantly, it helps determine the size of the filter press.

Let's say the say there are 2 filter presses, both dewater the same amount of slurry and operate in 4 hour cycles. One operates 12 hours a day and the other 24 hours a day. The filter press that operates for 12 hours will need to be twice as large in order to dewater the same amount of slurry as the one operating around the clock.

Do you want
expert advice on choosing the right dewatering system and filter press? Take our free assessment and get recommendations from our dewatering experts.

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