PERFODRUM DRD Rotary Drum Screw-Screen

Typical Applications:
  • Pre-treatment of Municipal Wastewater
  • Solids Recovery and Processing from Industrial Efflients
  • MBR Membrane Bioreactor Inlet Screening
  • Storm Overflows and Sea Outfalls

Operating Principle

DRD Rotary Drum Screw-Screens are integrated machines consisting of a screen, a screw conveyor and compactor. During operation, solids within the incoming flow will enter into the drum screen and progressively collect onto the screen mesh and cause it to gradually blind. The upstream water level will rise and at a predetermined level, the drum screen and screw conveyor will activate and rotate immersing a clean section of the screen into the effluent.
During rotation the solids or screenings will become inverted and then fall into the screw conveyor. Spray nozzles and a roller brush fixed to the periphery of the drum screen will clean away any residual solids from the mesh. The screenings are conveyed, compacted and dewatered and depending upon the solid properties, a volume reduction of around 40% DS or greater can be achieved prior to disposing the screenings into a skip or wheel bin.
A jet wash facility in the compaction zone will break down and remove faecal and other semi-solid or soluble matter and return it to the inlet flow. Additional jets can be installed in the transport zone to meet higher specifications of organic solids removal. Faecal matter washing efficiencies greater than 90% and screenings weight reduction of 50% can be achieved.
The compactor and wash system can be omitted to suit requirements such as CSO applications where the screenings are returned to the downstream sewer.

DRD rotary drum screw-screens can be supplied for direct installation into a channel or as a complete package inside a stainless-steel tank with or without the option of a bypass rake screen. Continuous bagging systems are available to receive screenings and abate odour, the screenings can then be sealed without any personal contact.

PERFODRUM DRD Specifications
Flow Capacities Up to 2100 l/s depending upon perforation size, effluent and solids contained within the flow
Fabrication: AISI: 304 or 316 Spiral: Mild steel or AISI: 304 or 316
Screen basket nominal ø 600, 800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, and 2400 mm diameter
Screen Perforation Sizes 0.5, 1, 2 mm in wedge wire
2, 3, 6, 7 mm perforated holes
DRD Operating Principle