Membrane stripping - production of nitrogen-rich fertilizers
Production of nitrogen-rich fertilizers starting from WWTP anaerobic sludge by membrane stripping
Digestion sludge contains an important amount
of nitrogen. The so-called centrate (the liquid part of these sludges, after
centrifugation), is normally conveyed back to the inlet of the WWTP. A new
process developed by Alpha Wassertechnik (https://www.alphawt.ch) and
Membratec allows the extraction of a large part of this nitrogen to be
exploited as a mineral fertilizer. This technology is based on a membrane
process that allows the dissolved gaseous components to be separated from their
liquid. 85% of the nitrogen contained in the centrate is thus concentrated as a
fertilizer in the form of ammonium sulphate, at a concentration of 80 gN / l.
This process has the following benefits for WWTPs:
- Valorisation of nitrogen waste as fertilizer.
- Reduction of the ammonium load in the wastewater treatment:
- Reduction in the use of oxygen in the biological treatment step;
- Reduction of the ammonium load in the treated waste water;
- Reduction of the N2O production (the main greenhouse gas produced by WWTPs), with the possibility of accessing Klik subsidies.
- Limited space requirement and modularity of the process (unlike stripping towers).
For further information: https://www.aquaetgas.ch/fr/eau/eaux-us%C3%A9es/ag2018-01_fa_p%C3%BCrro/
