Brackish Water Desalination Using a Mixed Bed of Anion Exchangers to Prevent Sulfate Scaling Without External Addition of Chemicals


Lehigh University has developed a reversible ion exchange-desalination (RIX-D) process. Desalination is a common method of salt-water purification, which is practiced throughout the world. The two products of salt water purification drinking water and leftover salty brine called concentrate. Unfortunately, the amount of drinking water that can be produced from a given volume of salt water is limited. Attempting to operate the desalination process at high recoveries causes the concentrate to become so salty that the solubility of some salts can be exceeded. This causes the formation of solid particles that can clog and damage the desalination plant. In order to prevent the formation of solids, two methods are practiced – chemicals called antiscalants are dosed in the feed water, and the recovery of the process is intentionally limited. Furthermore, the leftover brine must be disposed of through costly measures. The Reversible Ion Exchange Process (RIX-D) uses ion exchange to selectively remove certain ions, like sulfate, from the feed water. In the absence of sulfate, solids can no longer form and the desalination process is able to operate higher recovery resulting in significant cost savings to the desalination plant in three ways – more drinking water can be produced, antiscalants are no longer needed to be dosed, and less brine is produced which reduces disposal costs. The RIX-D process can be applied to any pre-existing desalination plant with minimal cost and requires no chemical input and little to no operator input.


Lehigh Tech ID#052113-01



Water pumping and purification systems, water filtration system, desalination and purification system, and water treatment or waste water recycling.


The technology’s process reduces the volume of concentrate brine for disposal, and savings will be made in the reduction in cost of disposal. The total cost of disposal varies, but can cost up to double the cost of desalination itself. For example, operations costs for the El Paso Desalination Plant are roughly $15.4 million per a year. A 50% reduction in volume of concentrate could, in theory, provide plant saving of up to $5 million a per a year.



Lehigh University is initially interested in licensing the technology.

App Type Country Serial No. Patent No. File Date Issued Date Expire Date
Provisional [PR] United States 61/828,477 5/29/2013   5/29/2014
Utility United States 14/289,134 5/28/2014    
For Information, Contact:
Alan Snyder
VP, Research & Grad Programs
Lehigh University
Arup Sengupta
Ryan Smith