Drying Solid Digestate

Biogas is produced by fermenting food waste, garden waste, biomass and slurry. This process generates digestate, which is then separated into solid digestate and liquid digestate.

Solid digestate contains relatively few nutrients. However, once dried, it can be used to improve soil structure. Our SWISS COMBI ecoTwin, which combines a SWISS COMBI ecoDry rotary dryer with a SWISS COMBI Belt Dryer, is ideal for this application. In the ecoDry, the material’s strong odour is neutralised during the drying process. The belt dryer uses the waste heat from the ecoDry rotary dryer to complete the drying of the solid digestate or to gently dry other materials. This makes the drying process particularly energy-efficient. However, it is also possible to dry solid digestate using an ecoDry rotary dryer alone.

Liquid digestate can be processed into granular or pelletised fertiliser in the SWISS COMBI ecoFertiliser Plant (eFP).