Hydro International Grit Removal System Adaptable For Intermittent Pumping

Hydro International Grit Removal System Adaptable For Intermittent Pumping
HeadCell grit removal system from Hydro International

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The HeadCell grit removal system from Hydro International can be adapted for intermittent operation by incorporating a deeper grit sump and can be configured to accept submersible pumps within the separation chamber.

“The HeadCell has been around for about 15 years and has generally been applicable to a range of plant sizes. Basically we’ve offered one operating mode and one pump configuration,” says Marcia Sherony, national sales manager for Hydro International in North America. “We now offer a larger-diameter grit sump for intermittent pumping or to utilize a submersible pump.”

Designed for new plant construction and retrofits, the modular, multiple-tray solids settleable concentrator features a stacked design that can remove grit 75 microns and larger. Tray diameters range from 4 feet to 12 feet; the number of trays can be varied to treat a range of flows.

Influent enters trays tangentially via the distribution header, splitting flow equally between the trays, setting up a rotary flow pattern that forces particles into a boundary layer. This forces grit particles toward the center of the unit into the underflow collection sump. De-gritted effluent leaves the chamber over a high-level weir that can be positioned on any of the basin’s four walls.

“We have systems installed at smaller plants that have a peak of about 2 mgd. Our largest installation is over 500 mgd,” Sherony says. “For a 2 mgd plant, we can use a 4-foot-diameter unit and a couple of trays. When you get into very large flows, 100 mgd, you need multiple units. But because they are the stacked-tray design, even if you have four large HeadCells, it’s a very small footprint. You could process about 92 mgd with a 100-micron cut point in a roughly 16- by 65-foot footprint.”

The grit removal system operates continuously without power. When intermittent pumping is utilized — and it is not necessarily recommended for every plant — at predetermined periods according to site conditions, fluidizing agitates the collected grit prior to it being pumped to the classifying and dewatering systems. The HeadCell can be designed to remove 85 to 95 percent of all grit entering the plant.

“Using our cost of grit calculator, you can input numbers from your plant and it will tell you how much grit costs you,” she says. “People don’t think about cleaning up the aeration basin; they don’t think that’s caused by poor grit removal. They think it’s normal maintenance that has to be done on a regular schedule, but it is often largely due to poor grit removal.”

The grit removal system is also suitable for pretreatment for membrane bioreactor and other advanced treatment processes. 866/615-8130; www.hydro-int.com.


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