Fermentation residues from biogas plants contain phosphorus, which is in great demand in agriculture as a fertilizer. As the natural deposits of phosphorus are dwindling, processes for recovering this nutrient offer a sustainable alternative for the production of phosphorus-based fertilizers.
Like phosphorus, nitrogen is also a component of bio-plant fermentation residues and can be recovered using processes developed at the Fraunhofer IGB.
Thermal digestion of fermentation residues
Using thermal processes, the Fraunhofer IGB scientists succeed in breaking down the fermentation residues from biogas plants into their components and recovering important valuable materials from them.
Stabilization trough drying, torrefaction or carbonization
In the production, preparation and processing of solids, drying is usually an essential process step. Drying processes are used, for example, to stabilize the shape of granulates, pellets or powders.
Torrefaction aims to increase the mass-related energy density and thus the calorific value of the raw material. It also increases the transport and storage capability of the raw material.
Recovery of nutrients and organic matter from agricultural residues