Digestate Treatment


Module with SiC-membrane stack
Pilot test unit for digestate treatment

The increase of recently built biogas plants throughout the last years led to a strong increase of the amount of digestate that has to be spread as fertilizer on agricultural land. All costs taken into account, i.e. for rental of this land or transport and storage of the digestate, biogas plants are often unable to be run economically feasible. Thus specific digestate treatment is necessary to reduce the amount of material that has to be deposed as well as raising its quality as a fertilizer. Therefore mechanical dewatering followed by ultrafiltration for a complete solid-liquid separation with sub sequential pelleting can be used. The gained nutrient-rich fractions can be marketed specifically.




  • Studies regarding solid-liquid separation using various dewatering equipment
  • Analysis of nutrient concentration in all fractions at solid-liquid separations (feed, retentate, filtrate)
  • Studies regarding the eligibility of membrane separation for digestate treatment
  • Studies regarding the eligibility of using the residues from mechanical dewatering and membrane filtration as a fertilizer


Technical equipment


  • Chamber filter press (with several filtercloth qualities; chamber volume: 3 - 15 L)
  • Oszillating sieve
  • Membrane filtration (modules for tubular and flat-sheet membranes usable; max. flow rate: 2 m³/h)
  • Extruder