Magnetic ion exchange drinking water treatment in a large-scale facility

Although the magnetic ion exchange(MIEX (R)) process for treating drinking water has been studied at both laboratory and pilot scale, it had not been demonstrated in a large-capacity plant until recently. This article describes the world's first large-scale application of the MIEX process at the Wanneroo Groundwater Treatment Plant-which has a capacity of 225 ML/d-in Perth, Western Australia. At Wanneroo, the MIEX drinking water treatment process is followed by conventional alum coagulation (MIEX-C), and this combined process operates in parallel with an enhanced coagulation (EC) treatment process with alum. On two occasions (summer and winter) with different influent water quality, water samples were collected from various points throughout the treatment plant and subjected to a range of analyses. The purpose of this study was to investigate the changes in the amount and type of organic carbon at various stages in the MIEX and coagulation treatment processes. Biologically available organic carbon was of particular interest. Overall, the MIEX-C process produced higher-quality water than the EC process. The MIEX pretreatment step appeared to increase the efficiency of the EC process for reducing dissolved organic carbon concentration and chlorine demand.