| abstract |
The invention relates to a method for the treatment of a material flow comprising at least one valuable substance of each of the following groups (A) amino acids, (B) carboxylic acids differing from amino acids, having 1 to 5 carbon atoms, and (C) inorganic salts, the method comprising the following steps: (1) treating the material flow by means of nanofiltration in order to obtain a retentate enriched with a valuable substance (A), (2) treating the permeate of step (1) by means of electrodialysis in order to obtain a concentrate enriched with a valuable substance (C), (3) treating the diluate of step (2) by means of a system (3) of two steps (4) and (5) interconnected either directly or indirectly, wherein (4) a treatment is carried out by means of reverse osmosis, and (5) a treatment is carried out by means of electrodialysis, wherein a concentrate enriched with a valuable substance (B) is obtained, (6) at least part of the retentate of step (4) is fed to step (5) either directly or indirectly, and (7) at least part of the diluate of step (5) is fed to step (4) either directly or indirectly. |