PUTTART® vertical dryer - granulator

The PUTTART® vertical dryer-granulator is a high capacity installation for simultaneous sludge drying and granulating and can be used for municipal and industrial sludge.

The unique drying-granulating combination results in a valuable pathogen-free, easy storage fertilizer end-product.

Vertical dryer - granulator

Mechanically dewatered sludge is extracted from the reception bunker and pumped to the coater. The coater puts a fresh layer of wet sludge around dry recycled granules. The coated granules enter the dryer from the top and fall onto the first tray. The tray is internally heated with thermal oil. This means that drying is done in an indirect way (no fire and explosion risk).

The granules are transported from the inner to the outer circumference of the tray by raking arms, mounted on a slowly rotating central shaft. At the outer side of the tray, the granules fall on the tray below is slightly larger in diameter than the one above. The granules are now transported back to the center. This zig-zag movement is repeated on the trays below.

At the bottom of the dryer the granules are collected and transported by a screw system and a bucket elevator to a screen. The screen separates the larger granules from the smaller ones. The small granules are recycled to the coater; the large granules are cooled and evacuated to storage.

Vapours are condensed while uncondensable gases (odours, VOC) are evacuated and destroyed by thermal oxidation.


  • Drying of municipal sludge (primary, secondary, digested,...)
  • Industrial sludge
  • Paper mill sludge
  • Manure, chicken litter...
  • Organic waste


  • Drying and granulating in one
  • Safe drying process: indirect dryer. No fire and explosion risk.
  • Wide range of capacities (from 3.000 to 14.0 00 kg/h water evaporation)
  • Low operating costs
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