Digestate Drying

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Biogas operators face increasing challenges in respect to the liquid manure ordinance, storage issues, the nutritional balance of fertilizer, and the application of liquid digestate. Pelletizing digestate is an excellent way to combat these challenges.

Benefits of Digestate:

  • Turn heavy liquid digestate into a dry product to lower transport costs
  • Store more digestate by reducing volume
  • Keep all beneficial nutrients intact while eradicating harmful bacteria
  • Use the resulting pellet fertilizer or market it for profit
  • Energy from a CHP can be reused instead of expelled
  • Evaporate 11 tons of water per day


A higher volume must be stored to allow for reduced application times. That means high investment costs and, as the case may be, a reclassification in the Hazardous Incident Ordinance. An Exhaust gas drying procedure is not only a very interesting economical solution, but considerably improves the overall situation of the plant and serves as active environmental protection.

Our exhaust gas drying is the ideal solution for these problems. There is half of the thermal energy of your CHP in the exhaust gas flow. It can be directed into the dryer instead of being discharged into the atmosphere. While the liquid is completely evaporated, all nutrients remain in the dried digestate in a concentrated form. You then have a valuable fertilizer for your own purposes or for marketing purposes.

The evaporation rate of water amounts to approximately 750 W per liter (2839 W per gallon) which is very close to ideal physical conditions.  Liquid digestate is mixed to a moisture content of 70% by a drying return line and screw conveyor and then transported into the dryer. In less than 6 minutes, the humidity is reduced to a residual moisture content of 10%. Your digestate product is completely hygienized. Thus, you have the option to market your dried digestate product as a fertilizer according to the fertilizer law.

The entire process is fully automated and is adjusted to varying outputs by means of an intelligent control. It does not matter if a smaller amount of gas is available at your CHP or if it is operated by control energy in different power ranges, the drying process is regulated automatically. An ARC (active remote control) monitors the procedure in real-time and saves all drive, temperature and control-relevant data in an interval of 5 seconds. The supplied energy quantity as well as the throughput are measured and recorded for determining the co-generation bonus.

We will be pleased to give you advice without obligation within the scope of a personal meeting.