WesTech Engineering, Inc.

- High-Rate Sludge Thickener Clarifier


The CONTRAFAST high-rate clarifier combines clarification and sludge thickening and eliminates the need for an additional sludge thickener.


The innovative CONTRAFAST clarifier is a high-rate sludge thickening clarifier/softener that combines clarification and sludge thickening in a single operation with a footprint 25-50% smaller than a conventional clarifier alone! Effluent from the CONTRAFAST system is ready to be sent to filter press for most applications.

The CONTRAFAST is capable of running at rise rates of 6 gpm/sq.ft. and higher - over 4 times the rate typically used for conventional clarifiers. In addition, the CONTRAFAST unit produces sludge with more than 10% solids by weight.



  • High rise rate
  • Thickened sludge
  • Pre-engineered design
  • Slude return pump
  • Pilot unit available


  • Small Footprint
  • Minimezes foundation size and cost
  • Eliminates separate sludge thickener
  • Less waste
  • Save design time and cost
  • Sludge thickening control
  • Confirm process sizing

  • Lime-soda softening
  • Surface water clarification
  • Backwash waste recovery
  • Cooling tower blowdown/side stream treatment