Many wastewater streams contain suspended solids that cannot be disposed of or cause problems in ‘downstream’ wastewater treatment systems.

To remove these solids from the wastewater Paques developed a compact settling system, the ASTRASEPARATOR®. The settling system combines compactness with trouble free operation and minimum maintenance. It removes suspended solids in a simple and effective way.

The ASTRASEPARATOR® can be used in both industrial and municipal wastewater treatment plants and in drinking and process water schemes.

Applications of solids removal by ASTRASEPARATOR®

  • Pre settlement in wastewater treatment systems
  • Post settlement of wastewater treatment schemes
  • Settlement in physical/chemical plants
  • Back-wash water treatment in drinking and process water production processes (see below)
  • Surface water treatment

Back-wash water treatment

Back wash water from sand filters, or granular activated carbon filters, in drinking water production schemes can be reused by implementing dedicated and highly efficient wash water treatment installations. Paques has substantial experience in this field applying ASTRASEPARATOR® tilted plate separators.

After passing the ASTRASEPARATOR® treated wash water is low in turbidity (typical output levels < 5 NTU) and may easily be reused in the primary water production plant. Furthermore, the concentrated sludge flow will be easier to handle. Waste water discharge is minimized while overall net production of the plant is increased.


  • Compact installation
  • Small footprint
  • High efficiency
  • Process integrated mixing and flocculation (if necessary)
  • Standardized components for all necessary capacities
  • Rigid polypropylene plate packs, resistant against corrosive media

Working principle

The water containing suspended solids is fed (1) into the inlet compartment (2) of the ASTRASEPARATOR®. It flows downwards into the tank and enters the plate pack at both sides through the inlet slots (3). The plate pack (4) consists of a number of flat plates, which are positioned at an angle. The total settling area and the plate distance are determined by the sludge settling characteristics. During the upward (laminar) transport of water (6), the sludge settles on the plates (5) and the clean water leaves the ASTRASEPARATOR® through the outlet duct (7) and outlet nozzle (8). The special design of this duct promotes high settling efficiencies. The sludge on the plates flows downwards (5) as counter current to the water flow (6). The water inlet at the sides of the plate pack promotes unhindered sludge flow, preventing the accumulation of sludge and possible plugging between the plates. The sludge is collected in the sludge hopper (9), where further thickening takes place. The configuration of the sludge hopper enables a homogeneous sludge discharge (10).