PWN Technologies, Dijkweg 1, 1916HA, Andijk, the Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands; Department of Biotechnologies, TU Delft, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands. Electronic address: [Email]
The results of this sampling campaign on pilot scale processes aim to evaluate the occurrence and behavior of trace organic micro-pollutants and metal elements during anion exchange treatment of surface water and the subsequent treatment of generated spent brine with two types of electrodialysis membrane pairs. This knowledge is relevant to assess the quality and reusability of secondary products created during brine treatment; specifically the excess of sodium chloride to be recycled onsite and the natural organic matter, mostly consisting of humic substances, which find multiple applications in the agricultural industry. This study highlights that (1) the attachment mechanism of organic micro-pollutants to anion exchange resin occurs through electrostatic interaction and the subsequent transfer through ion exchange membranes is restricted by size exclusion; and (2) the complexation of trace metals compounds with the natural organic matter partly explains their removal by anion exchange. Complexes remain stable during treatment of the brine with electrodialysis.