Biosolids ScreeningHydro International

Hydro-Sludge Screen™


Hydro-Sludge ScreenThe Hydro-Sludge™ Screen is a horizontal in-line coarse material separator comprising an inlet screening zone and a pressing (compacting) zone. The coarse material retained on the stainless steel inner screen surface, is transported to the stainless steel pressing zone and onward to the outlet by an Archimedean screw.

Compacted coarse material (screenings) are discharged by the action of a regulating cone controlled by detection of increased torque on the drive motor, into a suitable container.

The optimum pressure for sludge supply to the screen is between 14.5 and 17.4 psi. While the unit will tolerate higher pressure for brief periods, continuous increased pressure is not desirable.


  • Designed for either direct tanker, pumped feed or combination sludges
  • Ship-board preliminary treatment
  • Primary, secondary or imported sludge screening 



  • Enclosed system, reducing odor problems
  • Screening, dewatering and coarse material discharge in one operation
  • No washwater requirement
  • Fully automatic for either continuous or intermittent screening of sludges with varying dry solids content
  • Continuous coarse material separation under pressure with loss of pressure dependent on sludge thickness only 0.12" to 0.39" diameter screen perforations
  • Rugged construction using stainless steel and cast iron components
  • Fully manufactured, assembled, and tested in-house
  • PLC controls with HMI interface
  • Stellite tipped screw flighting
  • Bolted access hatch for inlet end access
  • Auto-reverse backpressure cone retraction
  • Reinforced dewatering zone screen


Operation:Hydro Sludge Screen

  • Flow enters through the center of a sludge inlet (red arrow)

  • Sludge passes through the perforation and exits via the sludge outlet (blue arrow), while the screenings are trapped inside

  • A rotating screw moves the screenings off the inside of the drum to the pressing zone

  • In the pressing zone, screenings are pressed against a retention cone which is balanced against the drive load of the screw

  • Dewatered screenings are discharged by gravity via the screenings outlet (brown arrow) 


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