In making an economic validation of RO and IX processes, the cost of discharging the concentrate is often important. However, the salt concentration of the feed is usually of primary interest. While the specific costs for demineralized water using IX is dependent on the salt concentration of the feed water, the specific cost for an RO plant is constant for a broad range of salt concentrations.
Secondly, the specific costs of the RO treated water are starting at a higher level so that the breakeven point (intersection) shows the designer where the salinity value of IX and RO have the same costs. Apart from the economic validation other reasons may appear as to why a RO or IX is selected for a process. In general, RO process is preferred if easy handling is a critical selection issue while IX is preferred if high selectivity is beneficial.
Process Solutions – On the Way for Future Growth
Lanxess believes that both IX and RO technologies will continue to strongly grow in the near future. Seawater desalination is rapidly growing with an expected growth rate of 12 per cent; brackish water at a slightly lower growth rate. The RO membrane process clearly has a bright future. And, with water treatment processes, demanding greater efficiency IX has a bright future.
The modern technology of water treatment requires the combination of several technologies, for example, the integration of different membrane processes (e.g Ultrafiltration and RO membrane separation) or the combination of several techniques like RO and IX, or RO and EDI. Lanxess now offers two state-of-the-art process solutions (RO and IX) to allow the process designer to optimize the water treatment process with the goal of a lower cost and higher reliability of water treatment for the user.
* Courteousy of PROCESS India. All authors work for branches of Lanxess