The Alfa Laval ALDRUM system is ideal for thickening of sludge prior to digestion or dewatering, and for reducing sludge volume prior to storage or transportation.


Compact, robust and efficient

  • Long-lasting filter cloth
  • Intermittent flushing saves water
  • Gentle treatment of flocculated feed saves polymer and gives high recovery
  • Safe design with bolted, hinged cover
  • Clean, enclosed, odour-free solution
The Alfa Laval ALDRUM rotary drum filters are designed for small to medium capacity sludge thickening. Installation couldn’t be simpler – just bolt it in place and connect the external power and piping. This well-proven solution is known for its robust, straightforward design, making the ALDRUM drum thickener a reliable and user-friendly product. You benefit from low water consumption as the drum is cleaned intermittently using either potable water, final effluent or treated filtrate.

How it works

The ALDRUM drum thickener works on the principle of conveying polyelectrolyte-treated sludge (a.k.a. flocculated sludge) through a slowly rotating drum filter. The sludge remains in the drum while the water phase passes through the filter cloth.

You can achieve the most efficient thickening by varying feed rate, polymer type and dosage, drum speed and spraying interval. Get the most cost-effective flocculation and polymer dosage by installing a flocculation reactor and/or mixing valve upstream of the actual drum thickener. A variety of filter cloths are available for new applications.

Discover our range of auxiliary equipment

  • Mixing valve: Ensures thorough mixing of polymer and sludge. Can be installed directly on to the drum thickener inlet or before the flocculation reactor
  • Flocculation reactor: Simple open reactor that kick-starts the creation of large and strong flocks. Can be installed directly onto the drum thickener inlet
  • Sludge hopper: Leads the thickened sludge to the sludge pump in a controlled and efficient manner
  • Basic control panel: For easy control of the drum thickener, including control of the level in the flocculation reactor (if fitted)
  • Advanced control panel: All-in-one control solution. Control of the plant’s feed pump, sludge pump and polymer pump, as well as the drum thickener, the level in the flocculation reactor and the sludge hopper