NFF
Non Fossil Fertilizer - Nitrogen recovery in industrial fertiliser quality
Duration: 01.03.2023-30.09.2023
Initial situation:
Sustainable energy sources such as biogas from organic substrates or residues are becoming increasingly important. In addition to methane, fermentation also produces large quantities of fermentation product, which contains nitrogen compounds, among other things. Although this is an essential nutrient, it can pollute the ecosystem in excessive concentrations and is therefore limited in its application as fertiliser. This means that fermentation products can only be used to a limited extent as a source of nutrients in agriculture in areas with high nitrate pollution of the groundwater. Fermentation products from industrial residues are generally prohibited as fertilisers under the Fertiliser Ordinance. The recovery of nutrients from fermentation products is therefore an important method of closing the biological cycle with the optimal utilisation of fermentation products.
The project:
Within the project, a prototype of an alternative membrane contactor is being constructed. This will be constructed using natural rubber materials as a hydrophobic membrane with which nitrogen can be recovered from fermentation products. The structure of the reactor is shown in the figure above.
The focus is on investigating the permeability of natural rubber for ammonium and its resistance to ammonium acceptors. The aim is to remove nitrogen in the form of ammonium from the fermentation product and bind it by reaction with an ammonium acceptor. This produces a nitrogen fertiliser that can be sold. The nitrogen-reduced fermentation products can also be used within "red areas" (areas where the nitrate content of the groundwater is higher than 50 mg per litre) if they are of agricultural origin. The nitrogen-reduced fermentation products from industrial residues can be utilised in accordance with the circular economy, e.g. within the construction industry.
Objectives:
The aim of the project is to generate ammonium compounds that have a significantly better transportability of the generated nitrogen-containing product compared to the products from existing processes. By dispensing with high process temperatures and pressures, this innovative process will require significantly less energy. It is envisaged that the products of the new technology can be used not only in agriculture but also in the chemical industry.
