What: Purification of sewage
Where: Sneek, Netherlands
Who: Bob van Zanten and Hans Wouters
When: 2014
Source: CADos

Cellulose Assisted Dewatering of Sludge

The object of the CADoS project is to develop and to build a prototype of the Cellulose Assisted Dewatering of Sludge (CADoS) water treatment concept at the Ulrum sewage-treatment plant. The CADoS principle will be applied to use a new sieving technology innovatively within an existing wastewater treatment process. The innovation consists of the sustainable reuse of toilet paper in sewage treatment plants. CADoS is the winner of the Waterinnovator of the Year 2014.

Wastewater carried via sewers to the treatment plant contains solid matter that includes a large proportion of cellulose. The cellulose stems from the use of toilet paper. The project will separate the solid matter containing cellulose that is present in the sewage water by means of a fine sieve and will use the separated solid matter for the dewatering of sewage sludge. The CADoS principle is being applied to attempt to reduce significantly the use of chemicals at the treatment plant, to consume less energy and to lower sludge processing costs. CADoS will also increase the energy yield from biogas in the fermentation of sludge.


The benefits are immediately visible: sludge dewatering is getting very simple, chemical consumption is minimized, biological treatment is relieved (lower energy), the biological sludge keeps all bound phosphate solid and much less sludge volume to be removed resulting in fewer transport movements.