Sludge Concenration

Backwashwater from drumfilters, sludge cones or fixed bed filters usually has a relatively poor TSS content. As a result big volumes and surfaces are needed for the storage of the sludge what results in high leaching rates, especially of Phosphorous.

WATER proved offers two systems to increase the TSS concentration in backwash water quickly and with a small footprint:

  • concentration with a Radial flow settler
  • concentration with a beltfilter
Radial Flow Settler

Radial flow settler are connected directly to the solids-outlet of the drumfilter. Because of their special design, solids sediment in the conical bottom of the device where they can be taken out automatically. Clear water is constantly going back to the system. TSS concentrations of up to 2% can be reached like that.

Depending on the water temperature, fish species, type of feed, etc., a certain fraction of the sludge in the radial flow settler may start to float. This can be handled with our automatic skimmer.

All our radial flow settlers are custom made.


With a beltfilter the TSS concentration can be raised up to 13%. To increase the TSS concentration a flocculant is added to the incoming backwash water from drumfilters, sludge cones or fixed bed filters. The flocculated particles dry on the beltfilter's belt and are scraped into a hopper at the end of the filter.

Regulation of the process is water level depending and automatic.

The thickened sludge can used as manure, in biogas plants or be composted.

Of course we provide all necessary accessories:

  • Flocculant - Polymer
  • Dosing and mixing units for flocculants
  • Mixer tanks
  • Sludge pumps
  • Switch cabinet construction
  • Phosphorus precipitation


Sludge thickening with a beltfilter
Your Advantages
  • Reduction of the storage footprint
  • Prevention of nutrient leaching
  • Improved effluent loads
  • Low energy consumption