Performance of a vibratory shear membrane fi ltration system during the treatment of magnetic ion exchange process concentrate

The performance of a vibratory shear enhanced processing (VSEP) unit used to treat waste generated from a magnetic ion exchange (MIEX) process is assessed. The unit was fitted with a NF-270 membrane (97% nominal rejection of MgSO4) with an internal membrane surface area of 37 m2. The vibration amplitude of the module was set at 12.7 mm. The system removes greater than 97% dissolved organic carbon as well as 70−85% multivalent solutes (Mg2+, Ca2+, SO2−) from the MIEX waste. The permeate generated was high in salt and was successfully 4 recycled to reduce the brine requirement for MIEX resin bead regeneration. Early operation in recirculating batch mode examined the effect of volumetric recoveries (in the permeate) ranging from 75–85%. Higher recovery had no significant influence on the performance of the system. System chemical cleaning was carried out every 14–16 batches. Batch durations generally extended in each subsequent cycle prior to cleaning, with the last batches taking up to five times longer than the first batch. The installation of VSEP has resulted in a reduced frequency of waste disposal from the facility and has also reduced the amount of make-up brine required for resin regeneration by 78%. © 2015 Elsevier B.V. All rights reserved.

The VSEP system unit implemented at Wanneroo groundwater treatment plant has been utilised to successfully treat waste produced from the MIEX regeneration process. In all cases, over 97% of the dissolved organic carbon in the MIEX waste was removed. Characterisation of collected samples indicates that the system removed a majority of divalent ions but is less selective towards monovalent and uncharged ions. Furthermore, organic characterisation of the permeate and feed streams showed that the permeate consisted of organics that were 400 Da smaller in average molecular weight than that observed in the feed. Changing the overall permeate recovery of the system between 75%, 80% and 85% exhibited no significant changes in performance. Exploration of batches in a collective sequence indicated a significant deterioration in flux as well as an extension in batch times for batches prior to chemical cleaning. Increasing the frequency of chemical cleaning could improve the overall performance of the system, reduce the time of operation and protect the membrane installed in the unit.