Optimised & user-friendly solutions


Digestate evaporation

The digestate evaporation system Vapogant processes the digestate from the biogas plant to such an extent that a usable, concentrated fertiliser with reduced water content is produced.
We remove a large part of the water from the digestate by vacuum evaporation using the waste heat from the CHP unit. At the same time, volatile nitrogen is bound so that losses during application are minimised and the nitrogen is available in the form of ammonium sulphate solution (ASS).
The aim is to use the available waste heat to thicken or refine 100% of the fermentation products produced in the biogas plant. This is achieved through a very high evaporation capacity of 2.5 litres per kW of thermal output. With a plant size of 500 kW thermal, this corresponds to a volume reduction of approx. 10,000 m³ per year.
The plant is available in a module size of 400 kW or 500 kW.

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What can the VAPOGANT?

Waste heat utilisation

  • Automatically controlled 100% heat reduction
  • Multiple use (multistage) through vacuum system
  • Even at high outside temperatures
  • Heat recovery:
    • 1. evaporation
    • 2. fermenter heating
  • Sichere Zusatzeinnahme durch KWK wenn vorhanden

Digestate storage capacity

  • Reduction of the fermentation residue quantity up to 70 %/ annual quantity approx. 10,000 m³
  • Enormous thickening of the liquid phase to up to 20 % TS
  • Low space requirement of only 100 m²
  • No additional fermentation residue storage capacity required
  • No Major Accidents Ordinance necessary
  • Fermentation residue storage usually brings no additional benefit

170 kg N-problem

  • Own ASS production
  • Use of nitrogen fertiliser beyond 170 kg N-limit possible
  • ASS is a valuable commercial fertiliser
  • Very low N-loss during storage and application
  • Targeted nutrient delivery is not a cost factor, but an additional income


  • 100 % closed system
  • Complete condensate treatment
  • No smells
  • No waste gases
  • No noise (60 dB in 10 m)
  • No fine dust
  • Exhaust gas recirculation Vacuum pump into the gas system of the biogas plant or activated carbon filter
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How does the Vapogant work?


How does our Vapogant digestate evaporation system actually work? Patrick Fries explains in our video our evaporation technology of the digestate evaporation Vapogant.

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Circuit of the digestate evaporation Vapogant

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Technical process of digestate evaporation Vapogant

Usage of the recovered ammonium sulphate solution (ASS)

The ammonium sulphate obtained in the plant can be processed in various ways according to customer requirements:

For your company

The ASS is stored in separate storage tanks (e.g. 100 m³, horizontal) and can then be sprayed with a field sprayer or CULTAN Technology to be spread. - Ideal for supplying the plants with nitrogen according to their needs.

For commercial purposes

As ASS is considered a mineral fertiliser, it can be resold as a valuable commercial fertiliser.

Distillate utilisation

The distillate discharged from the evaporation process and cleaned by means of a vapour scrubber can be further processed in different ways depending on customer requirements.

Use of the distillate for operational purposes

Various possibilities of operational use are available here: Storage of water for use as washing water for stables and areas, as dilution water for plant protection products and liquid fertilisers, etc.

Evaporation of the distillate via the wet cooling tower

As a cooling unit is necessary for the operation of the plant, part of the water can also be evaporated directly and continuously via a cooling tower. In addition, the cooled water is used as cooling medium.

Indirect and direct discharge of the distillate

The water is fed continuously, if necessary combined with an upstream distillate treatment module, into a receiving watercourse or can be percolated.

Reference customers

Need more information?

Then you can download technical information here, or just give us a call!