Designed to reduce the amount of sludge produced and related water losses, Actiflo® HCS (for High Concentration Sludge) is an Actiflo system equipped with an outside recycling loop.

ACTIFLO® HCS’ principal feature is that it comes with a specific hydrocylone* and an external recirculation loop.
After settling, the sludge/microsand mixture is pumped to the hydrocyclone where the microsand is thoroughly washed before being injected back into the flocculation tank. The flow of sludge is directed in part towards the recirculation loop with the other part being discharged. Thanks to a fine regulation system, Actiflo HCS reduces the amount of sludge produced by 2 to 3 times, while still maintaining a high clarification level.


  • A 50 – 80% reduction in sludge volume
  • Water losses reduced to under 0.5%
  • A reduction (in size and number) of the facilities used to treat dirty water/sludge from the Actiflo
  • Easy to implement in refurbishing projects


ACTIFLO® HCS is applicable to several industrial and municipal situations.

Municipal applications

  • Treatment of river water and turbidity peaks

Industrial applications

  • Effluents treatment
  • Process water production