Rim-Flo® Circular Clarifier- Achieves Greater Than 50% Hydraulic Efficiency Compared to Traditional Center Feed Clarifiers.

Used as secondary activated sludge clarifiers, Rim-Flo® circular clarifiers offer greater capacity, higher overflow rates, optimum hydraulic stability, full surface and feed channel skimming, maximum design versatility and lower construction costs.

Rim-Flo® Circular Clarifier

Because of its hydraulic efficiency, a Rim-Flo® Circular Clarifier can be designed with as much as 50 percent less surface area than a conventional center feed clarifier, with a corresponding decrease in cost.  The Rim-Flo® clarifier also makes full use of its tank volume by eliminating short circuiting.  Locating the influent and effluent channels around the tank periphery permits effective skimming of the entire tank surface as well as the influent raceway.

The Rim-Flo® circular clarifier is a peripheral-feed, peripheral-overflow clarifier designed for optimum activated sludge secondary settling tank performance. More than 650 basins around the world ranging in size from 15m (50ft) to 67m (220ft) have been equipped with Rim-Flo® peripheral feed channels.

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Siemens Video

More Information

  • Channels - varied cross section maintains constant velocity, prevents deposition of solids; confined influent assures controlled headloss; peripheral effluent reduces short circuiting and makes weir and channel cleaning easy 
  • Orifices - correct size, length and spacing eliminates ‘jetting action’ into basin and spiral flow vectors; spacing prevents solids deposition and permits equal flow distribution around tank periphery
  • Influent Skirt Baffle - extends five feet below water surface to define clear liquid zone; allows low inlet velocities, defines inlet completely around the periphery for uniform flow distribution
  • Raceway Scum Removal - scum is concentrated in a small area easily accessible from outside the basin


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Allen Lepak
Product Manager - Circular Clarifiers
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Rim-Flo® Circular Clarifier

Featured Case Studies
Rim-Flo® Clarifier at Neuse River WWTP 

Click here for a narrated presentation on the benefits of Rim-Flo® Circular Clarifiers

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