Why Screen Printers Should Use a Filtration System  | Screenprinting.com

If you have ever had to pay for a drain cleaning service or plumber to come to your shop to unclog your drain, you already know why you should be using a filtration system underneath your washout booth. Filtration systems keep solids from washing down the drain, clogging up your pipes, and creating a lot of stress for you. Let’s go over why printers need a filtration system and how to use it. 

A filtration system sits under a washout booth as water drips into the filters

Photo by Symmetree Clothing

WHAT IS A FILTRATION SYSTEM?

The purpose of a filtration system is to capture solids that come from emulsion and ink that do not dissolve in water and prevent them from going down the drain. Over time, as the reclaimed emulsion and small bits of ink travel down the pipes, they will stick to the sides and eventually completely clog the pipes. Rather than spending a ton of money to dig up and replace those pipes, invest in a filtration system. Here’s how it works.

A filtration system has a PVC pipe, which attaches underneath your washout booth, that funnels the water to a tank with filters designed to catch different sizes of particulate. The first filter catches all the big particles. Then the water goes through a series of three reusable screens: 110, 156, and 200 meshes.

Next, the filtered water flows into a holding tank where a high-powered industrial sump pump is triggered, pushing the water through the final two stages: a 70- and 20-micron disposable filter.

Once the refuse has gone through this six-stage filtering process, the water has been strained multiple times and most solids have been removed. Any remaining particulate has been reduced to 20 microns (0.000787402 inches), making it small enough to go down the drain without constantly worrying about clogging your drain. 

The main goal is to catch the solids. These are emulsions, and if you’re cleaning your screens and squeegees in the sink, inks, and pigments too. Every time you spray out a screen or reclaim that screen, the emulsion is going down the drain. Inks often remain congealed as a glob and sometimes even pieces of tape can get washed off and go down the drain. If you’re not using a filtration system, all of these go through your pipes.

WHO SHOULD USE A FILTRATION SYSTEM?

The short answer is simple: everyone should be using a filtration system. Small operations that clean five screens or less a day may not be flushing enough solids down the drain to draw the attention of city regulators or clog up pipes, but it’s still a good practice to have. Whether you purchase a filtration unit or create your own (more on this later), filtering solids out of the wastewater is always recommended. 

If your shop is cleaning 10 or more screens a day, at least five days a week, a filtration system will save your bacon. Would you rather filter out solids now, or pay out-of-pocket to replace your pipes later? The answer is simple: invest now and cut out the worry.

RELATED: DISPOSING OF HAZARDOUS SCREEN PRINT SHOP WASTE

A hand holds a pressure washer and points it at a screen sitting in a washout booth

Photo by Symmetree Clothing

FOLLOWING THE RULES

Every city has its own regulations and ordinances regarding what screen printing shops can legally put down the drain. All printers need to be aware of these for wherever their shop is located. If you want to be proactive, it’s a good idea to have an independent water testing service come out to evaluate.

This allows you to take measures to eliminate any problems before you get fined, and you also have the peace of mind of knowing if you are compliant or not. If you are using a water filtration system, the evaluation also can tell you how effectively the system is working.

RELATED: HOW TO DO ECO-FRIENDLY SCREEN PRINTING

CREATE YOUR OWN DIY FILTRATION SYSTEM

Need filtration, but don’t have the budget to buy a system? You can make one using barrels, a hose, and some creativity. Here’s how: 

  1. Source a couple of barrels or large tubs to catch water and solids from your washout setup.
  2. Run a hose from your washout booth to the first barrel. Think of this system as a fountain. Water and particulates should be allowed to settle, then run into the next barrel for extra filtration.
  3. Place a 16x20 screen in each barrel to filter out solids. Depending on the clean water standards in your area, use 2 or 3 screens of different mesh sizes:110, 156, and 200 mesh.
  4. Do a test run to make sure that your DIY filtration system is catching the solids properly. Make adjustments if necessary.

A pipe brings water to a bucket with mesh on top

Photo by Abi-Saad Print & Design

CHECK THE FILTERS OFTEN

Over time, the screens or filters in a filtration system will fill up with solids. While you can clean the screens with a rag or compressed air, eventually they’ll need to be replaced. Check the filters regularly to gauge when you’ll need to replace them. 

DISPOSING OF SOLIDS

If any solids in your filtration system are still wet, pull them out of the filtration system and allow them to fully dry before disposing of them. Depending on your city’s regulations, you may not be able to throw dried filters in the regular trash. If not, you’ll need to contact a waste removal service to come and pick it up.

The good news is that screens for the filtration system are easy and inexpensive to replace: they’re just 16x20 screen printing screens. Pick new ones up wherever you buy screen printing screens. Remember, you’ll need 3 different mesh counts—110 mesh, 156 mesh, and 200 mesh—to properly filter out solids. 

Filtration is great for your pipes and the environment. Investing in a filtration system means investing in your plumbing, too. You can keep reclaiming screens without worrying about having to replace those pipes. 

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