Modified stripping process, wherein the ammonium nitrogen is removed from digestates by using only exhaust heat from the CHP without the use of bases, acids or external stripping media. Binding of ammonia preferred with FGD gypsum to produce a concentrated ammonium sulfate solution and solid calcium carbonate fertilizer.
Advantages of the GNS Technology compared with Conventional Stripping or Evaporation Processes:
– Removal of NH4-N from a roughly separated liquid digestate (TS 5 – 7 %) without fine separation.
– Secure control of foaming behavior.
– No use of acids and bases in the digestate.
– Combined removal of CO2 and NH3 and combined chemical bond with FGD gypsum.
– Halved salinity and retained pH buffering ability after treatment (digestate will be not alkaline).
– At > 70 °C sanitizing effect and additional disintegration effect.