The ALDRUM sludge thickening system enables you to reduce your sludge volume by as much as 90%. It is ideal for thickening prior to processes such as digestion or dewatering, and for reducing sludge volume prior to storage or transportation.


Easy to install and maintain, the ALDRUM mechanical sludge thickener could not 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.

Optimized thickening

ALDRUM drum thickeners can be adjusted to suit particular sludge thickening needs. The most efficient thickening is found by varying the feed rate, the polymer type and dosage, flocculation mixer speed (if fitted), drum speed, angle of the drum, and the spraying interval. A variety of different filter cloths are also available for new applications.

Alfa Laval provides a full range of solutions for wastewater facilities such as decanter centrifuges, spiral heat exchangers and auxiliary equipment.



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.

Water consumption is low due to intermittent cleaning of the drum using either potable water, final effluent or treated filtrate. The ALDRUM can be adjusted to suit individual sludge thickening needs. It is possible to achieve the most efficient thickening by varying the feed rate, the polymer type and dosage, the drum speed and the spraying interval. The most cost-effective flocculation and polymer dosage is achieved by installing a flocculation reactor and/or mixing valve upstream of the actual drum thickener.

Meeting your exact requirements

A selection of auxiliary equipment is available for the complete ALDRUM range

Mixing valve: Ensures thorough mixing of polymer and sludge. Can be installed directly onto the inlet of the drum thickener, or before the flocculation reactor

Flocculation reactor: Simple open reactor that kick-starts the creation of largeand strong flocks. Can be installed directly onto the inlet ofthe drum thickener

Sludge hopper: Leads the thickened sludge to the sludge pump in a controlled and efficient manner

Basic control panel: Straightforward, user-friendly 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.