RSS Externally Fed Drum Screens

Self-Cleaning Externally Fed Rotary Drum Screen

The RSS Externally Fed Rotary Drum Screen is a reliable self-cleaning wedge wire screen for both municipal wastewater operations as well as many industrial screen applications. This screening technology performs particularly well in wastewater with high oil or grease loadings as well as scum applications that can blind other types of screens.

Within municipal wastewater, RSS screens are used for fine screening primary sewage influent at the headworks as well as the screening of clarifier scum. Industrial screen applications that commonly use JWC’s externally fed drum screens include meat and poultry processing, seafood offal effluent, and pulp and paper debarking.

The RSS Externally Fed Rotary Drum Screen is constructed of slotted stainless wedge wire and cylindrical drums that rotate on two pillow block bearings. The screen typically has openings ranging from 0.100 to 0.010 inches and features 100% overflow protection from blinding for flows up to 5.0 mgd.

Method of Operation

Raw influent enters a headbox which distributes the flow evenly across the full length of the rear, upper external surface of the rotating drum screen. As water passes through the screen, solids are retained on the outside of the screen drum and are carried by rotation around to the front of the screen, where they are removed by a fixed doctor blade. The screened water cascades down inside the drum and falls through the bottom, creating a vigorous backwash action. This action, together with the use of internal water sprays, has a combined effect of self-cleaning the drum on every revolution.


  • 100% overflow protection for designed flow up to 5.0 mgd
  • More material recovery for re-use or improved industrial wastewater production
  • Customized to fit into existing infrastructure


  • All 304 stainless steel construction
  • Headbox with overflow protection
  • Solid unitary frame
  • Wedge wire drum
  • Doctor blade assembly with Monel blade
  • Internal spray bar


  • Flows from 110 to 4000 GPM
  • Drum diameters range from 25 to 36 inches
  • Drum lengths range from 12 to 120 inches