The Highest Quality Effluent

The Spiraflo is a peripheral feed clarifier designed for superior removal of suspended solids that could be used in a primary, secondary or tertiary clarification system. The wastewater enters the outer perimeter of the clarifier tank and is directed along the narrow raceway formed by the skirt and the outer wall. This flow pattern dissipates the wastewater’s hydraulic energy as it flows around the raceway, eventually spiraling down underneath the skirt and into the main settling area. The flow travels inward from the skirt towards the center of the tank, coinciding with the direction of the sludge, and the clarified water rises into the centrally located effluent weir trough. The combination of the spiraling flow pattern and the skirt eliminates all possibility of short-circuiting and provides better utilization of the total tank volume for more effective settling.


  • Hydraulic flow pattern minimizes problems usually associated with center-feed clarifiers such as waterfall effect, sludge wall creep and short circuiting
  • Suspended solids are retained in the sludge blanket as flow travels underneath the skirt
  • Wastewater travels inward from the skirt towards the center of the tank which assists in moving sludge to the central hopper
  • Independent laboratory tests confirm peripheral-feed spiral clarifiers perform two to four times better hydraulically than center-feed clarifiers.