Protocols for electrodialysis. Membrane selection, membrane fouling and design

Spent regenerate streams from anion exchange (AIX) processes are rich in natural organic matter (NOM) and salts, and are formed during the implementation of this technology. Recently, new initiatives consider these streams as a resource for regeneration salts and fertilizers (NOM). At Vitens the well-known HumVi technology using nanofiltration (NF) is exactly aiming at this; and the HumVi process is recently implemented at full-scale in Spannenburg. The HumVi technology could not directly be employed at Andijk III because of the presence of sulphates in the spent AIX regenerate of PWN. An alternative was found in double electrodialysis (ED) treatment recovering regeneration salts and a potential fertilizer (NOM). The so-called TKI NOMixed was successfully constructed together with project partners PWN, PWN Technologies and KWR, and was awarded by RvO. The TKI NOMixed project aimed at developing tools to support the full-scale ED design for the treatment of spent AIX regenerate streams from Andijk III.