The requirements for the selective removal of sodium from drain water i.e. the 100% separation of sodium from nitrate and phosphate and the need to be able to keep them separate after removal from the water, were explained to the audience. Further, it was shown that ion exchange is the only commercially available technology that can achieve such a separation. The results of a successful demonstration during the 2018 season of a specific ion exchange process called the Sodium Reduction Unit (SRU) were shared with the audience. Lastly, the demonstration in 2018 highlighted two aspects, pH-control and the treatment of the NaCl concentrate, that needed to be finalised before the SRU-process will be market ready.
Ion exchange in the treatment of irrigation water