Wastewater contains organic materials, but inorganic and organic solids also make their way into sewer and septic systems. How do these items get into the wastewater? It depends on the setting. Homeowners with a septic system may not realize the damage that’s caused by flushing tampon applicators or using too much toilet paper. Children may flush toys, coins, or marbles down the toilet and never tell their parents. In a city setting, items like candy wrappers or water bottles may blow into the street on recycling days and end up in storm drains.
When items like children’s small toys, plastic wrappers, and other personal products get flushed or go down a drain, it’s a problem. Whether it’s intentional or not, plastics, glass, and metal items do not break down. Items like paper towels, cigarette butts, and diapers may break down, but they do so slowly. If they’re not removed in the early stages of water treatment, it can block pipes and damage water treatment equipment. The screening process is an essential first step in any water treatment plant.
Wastewater treatment plants have screens to capture these items before they make it into grit removal systems, clarifiers, aerators, etc. Screens are also helpful in industrial settings like paper mills with wood pulp, wineries where the grape skins and pulp need to be removed before the yeast is added, or breweries where grains and hops need removal before yeast is added for the fermentation process.
Who removes the items from the screens that are getting blocked by these solids? That’s where a mechanical rake comes in. Rakes continually move across a screen to remove the items that are trapped. There are different types of rakes. One of the most efficient is the Lakeside Raptor® FalconRake® Bar Screen. How does this system work, and how does it compare to the Duperon FlexRake?
How a Bar Screen Works?
A bar screen is a vertical screening system with multiple rakes. Those rakes are on a link system that continually moves them around the vertical screen. The rakes are spaced evenly and continually rotate around the screen and tank floor. The screen captures items like plastics, sticks, logs, rocks, glass, etc. and the rakes scoop them up as it passes under the bottom of the screen. They travel up the back and are dropped into a discharge chute as the rakes pass back over the top of the bar screen. From there, items can be washed and recycled or composted, and the rakes continue in another circle to repeat the process.
When you’re looking at bar screens. There are a few things to keep in mind. First, look for construction that prevents corrosion. Stainless steel is the best. After that, you want to look at the placement of bearings, bushings, guides, and sprockets. If they’re underwater, repairs may be more common and difficult to manage. Efficiency and headroom are other factors to consider.
The Pros and Cons of the Duperon FlexRake
The Duperon FlexRake is engineered specifically to meet your demands in many of the same ways the Raptor® FalconRake® Bar Screen does. The link system can hold up to a total of 60,000 pounds, which is impressive. The links are self-lubricating, so the maintenance is minimal. Gear motors are also sealed to help prevent excessive wear. Bearings, bushings, guides, and sprockets are in higher positions to also reduce the risk of jamming, which can lead to excessive maintenance or repair. It’s also designed to avoid jams when the debris is larger than usual. If something larger goes through the screen rake, you do not have to shut it down and have someone manually remove it.
The bar screen is cleaned automatically. That makes it possible to run it 24 hours a day without having a person to operate it. It’s installed in a vertical or almost vertical position. The motor is low RPM and energy-efficient.
There are several models available. Some are better for industrial settings like food processing plants and breweries, others are ideal for wastewater plants. To find the right screen rake, you need to look at the bar opening (as small as 1/5th of an inch up to just over an inch). Look at the installation angle, too.
How Does the Lakeside Raptor® FalconRake® Bar Screen Compare?
How does the Lakeside Raptor® FalconRake® Bar Screen compare? Much of it, including the chain link system, is crafted from stainless steel, and you get a choice. You can choose 304 stainless steel or 316. Both provide protection from corrosion, but 316 has more nickel and offers more protection in water that is chlorinated or contains more chlorides. If you treat water that has high chloride levels, consider 316 for the best protection from corrosion.
The drive system is low horsepower and incredibly efficient. Lower electricity costs in your municipality by choosing this bar screen. Variable speeds ensure comprehensive cleaning of the screen. The rake is stainless steel, and the ultra-high-molecular-weight polyethylene scraper is also durable and long-lasting. Teeth on the rake fit into the screening for optimal removal. If you’re worried about possible damage happening, don’t worry about it with this model. The bearings, bushings, guides, and sprockets are located near the top to reduce repairs from jams. It’s very unlikely that this bar screen system will need repairs. If it ever does, the drive system is above the water, which makes it much easier to manage.
With over a dozen rakes working together to remove solids, it’s an efficient removal process and headloss is minimal. It’s also adjustable, so you can space the bars to meet your needs. Bar spacing can be as little as ¼th of an inch to much larger sizes. You can also have a cover added to minimize odors. Teardrop-shaped bars are optional and reduce headloss even more. There’s also an optional weather protection system and explosion-proof design to provide peace of mind. Our Lakeside experts will help you determine the appropriate bar screen.
Where should you use the Raptor® FalconRake® Bar Screen? It’s useful in industrial and municipal settings. It’s an ideal screening system in a wastewater treatment plant. You can use it in your pump stations or sewer overflows. If you own a brewery, winery, or food processing plant, it’s good in those settings, too. As the system is customized to match the depth you need, you’re certain to have a screening and rake system that matches your needs.
Pair the Raptor® FalconRake® Bar Screen with a Raptor® Wash Press to clean, compact, and dewater the items that the bar screen removes. The Raptor® Wash Press cleans and presses the trapped materials to reduce the volume and weight of materials that go to the landfill. Lower volume and weight mean less money spent disposing of these items in a landfill. It also helps reduce the amount of waste going to the landfill.
For more than 90 years, Lakeside Equipment has provided solutions for treatment plant designers and engineers. Lakeside’s experience with water purification and water treatment processes cannot be matched. Our engineers will design a system that meets your needs and matches your budget. Our goal is to design a system that is built to last, and should you ever need parts, we have a stellar parts department who are happy to help you.
For more information on how you can achieve Lakeside quality and performance, contact one of our experts at 630-837-5640, email us at sales@lakeside-equipmnet.com or visit our website www.lakeside-equipment.com
