Pressing Onward: A Dewatering Blog

Overview of Evoqua's Lab Service Request Form

By Michael Stock


Choosing an Evoqua brand filter press is a multi-step process. One of the first steps is sending a sample of the slurry you will be dewatering to our state-of-the-art laboratory for testing. Based on the lab results we can recommend a filter press and dewatering system that will meet all of your dewatering needs.

Along with the slurry sample, we need a completed copy of our lab request form telling us a little bit about your current dewatering process and the sample. As with most forms, it asks for a lot of information. Some of which you might know, some you might not. But there are a few key pieces of information that we need to have. Read on to find out what those pieces of information are.


Dewatering Process

 For our lab to help you design the best dewatering system, we need to know a little bit more about your application. You can either draw it out or write it down as best you can. This information will give us a picture of the current process and what can be done (or what equipment you will need) to improve that process.

  • What treatment processes are employed (chemical, biological, etc)?
  • How many days a week does equipment operate and produce a slurry?
  • What volume of slurry and dry solids are produced per day?

Slurry Characteristics

Next, we need to know a little bit about the slurry that you will be dewatering, in order to run the proper tests and make equipment recommendations. We will need to know:

  • Composition of solids and liquids
  • TSS (total suspended solids) as a percent of weight
  • Specific gravity (g/ml)
  • pH level of the slurry

Cake Characteristics

Proper filter cake formation is an important part of a smoothly running dewatering system. We will need to know what goals need to be met in terms of filter cake formation, which includes:

  • Desired solids concentration, as a percent of weight
  • Desired wet cake density

With this information we can recommend the best material for filter cloths and if it would be beneficial to add a sludge dryer to the planned dewatering system.


Test Conditions

Finally, the following questions will need to be answered to guide our lab technicians as they test the sample:

  • Are there any limitations to what can be used to condition the slurry?
  • Can the slurry be heated?
  • Is cake washing required?
  • Are there any equipment materials of construction issues?

Are you ready to start your journey to a new filter press? Or maybe you just want more information about designing a dewatering system? Either way, our assessment is free for you to take along as a resource.

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