Static Screens in Wastewater Treatment: Applications and Advantages

One of the first steps a wastewater treatment plant takes to treat water is to run it through a static screen. If your plant isn’t performing this preliminary treatment step, it’s worth your consideration as they’re a cost-effective way to get a jump start on wastewater treatment.

What Does a Static Screen Do?

When wastewater flows into a treatment plant, a static screen sits in front of the remaining wastewater equipment. Wastewater enters the system, passing through a stationary static screen first to remove as many solids as possible.

Think of it like a mesh screen that keeps bugs from entering your window at home. In this case, it’s a durable screen that catches particles like plastics, feminine products, foods that weren’t digested, hardened particles of grease, and paper products. 

Items that get captured are composted or removed and taken to a landfill. Many plants compost them over time, and that compost can be used in forests. This makes it easier for the next stages of wastewater treatment, such as grit removal.

In addition to a municipal wastewater treatment system, static screens benefit businesses that are under orders to pre-treat industrial wastewater or who want to do their part. It includes companies like chemical processing plants, paper mills, breweries, food processing plants, and plastic and metal processing plants. If you have a stormwater system, they are fantastic for removing plastics, trash, and fallen sticks and branches after a storm.

Learn About the Different Types of Static Screens

There are different types of static screens, including two primary ones that most plants use. The options include:

Band Screens

Band screens are typically installed at the start of a single flow or direct flow channel. It has guides along each edge of the screen panels to ensure movement and alignment remain steady as the chains move around the system to keep the static screens in constant motion. 

The filter mesh is welded and has a frame that acts as a bucket that deposits materials into a collection area. As materials are deposited, spray nozzles clear the grills of debris.

Step Screens

Step screens have different stainless-steel bars with the screen that moves upward to the top, depositing the solids they collect. It almost resembles an escalator. If you can imagine an escalator with mesh that catches the materials instead of solid steps, you have a good understanding of what step screens look like.  

Wedge Wire Screens

Wire wedge screens are self-supporting and either a cylinder or flat panel. Wastewater travels onto the panel or cylinder and falls through the mesh, while solids go over the top to the collection area. It’s usually made from stainless steel due to its durability and anti-corrosion qualities. 

Step and wedge wire screens are the most commonly used static screens, but it’s important to consider what’s best for your wastewater treatment plant. The current design, space, and budgetary constrictions all influence your final decision.

Advantages of Static Screens in Wastewater Treatment

What are the advantages of static screens in wastewater treatment? One of the first benefits is that they’re cost-effective. They do not require electricity, and the purchase and installation costs are not out of reach, especially when you consider that they help make the rest of the wastewater treatment process a little easier to manage. Static screens also require very little maintenance, so you won’t need to spend a lot of time training or hiring additional workers to keep the screens maintained.

They clean themselves with water spray or bar rakes that clear the screen’s bars as the system moves around with the water’s current. Some are also self-reversing to clear any jams that may occur after a storm where large branches enter systems that combine wastewater and stormwater runoff.

Static screens do their job effectively. The mesh screens capture a lot. They can remove small particles of solidified grease, corn skins that are harder for a body to digest, or bone particles from animals that get into a sewer and end up in wastewater. With these items removed before the remaining wastewater treatment measures take place, it eases wear and tear on equipment and gets the treatment process started faster.

With a static screen, they don’t need ideal conditions in order to work correctly. It doesn’t matter if flow rates increase or decrease or if temperatures are colder or hotter than usual. Static screens will work effectively in any condition.

Because static screens come in a variety of sizes and formats, it’s easy to fit one into your existing system. Some require very little headroom. When you’re shopping for the best static screen, finding a variety of sizes ends up helping out if you have little space.

Tips for Choosing the Right Static Screen for Your Facility

The best static screen for wastewater treatment depends on your current setup. Work with an expert in wastewater treatment equipment to learn more about your options, the costs, and how to incorporate static screens in your plant.

Lakeside Equipment brings decades of expertise in water treatment to the table. We offer a variety of screens to ensure every customer gets the right equipment for their needs. Our line-up includes:

  • Raptor® FalconRake Bar Screen: This step system doesn’t require much space and is a cost-effective and low-maintenance option. Bars can be spaced as close as ¼ inch.
  • Raptor® Fine Screen: The Fine Screen is a cylinder static mesh screen that’s angled and has a rotating rake that travels around the screen to clean between the bars, which prevents clogs.
  • Raptor® Micro Strainer: The Micro Strainer is meant for lower use in a smaller facility. It’s a great option for a business that wants to pre-treat wastewater or for a smaller municipality. Stainless steel components and thicker baskets and tubes increase the system’s durability and lifespan.
  • Raptor® Multi-Rake Bar Screen: Stainless steel construction, including the roller chain, with rectangular or trapezoidal bars that act as steps and capture solids. This system has an auto-reverse to prevent jams.
  • Raptor® Rotary Strainer Screen: This wedge wire system is designed with mesh openings of 0.01 to 0.1 inches. It’s in a self-contained unit with stainless-steel construction to prevent corrosion. 
  • Raptor® Rotating Drum Screen: Wedge screen systems can use the cylinder mesh system, and that’s what this rotating drum screen does. The stainless-steel drum captures solids, while the liquids pass through. It’s a multi-purpose system that screens, washes, compacts, and dewaters.

Ask us about our line of Raptor® screens for your larger wastewater treatment plant or the Raptor® Micro Strainer for small facilities. Our wastewater equipment specialists help you make the right choice that’s in your budget and does everything you expect.