Reusing and recycling dialysis reverse osmosis system reject water

Water is at the very core of the dialytic process—both water quantity and water quality—the two being interdependent. Meanwhile, both are under increasing global stress.1 Coincident with this, despite the uncertainties around accurate data from emerging nations, worldwide incident and prevalent dialysis numbers are burgeoning, especially as nations such as China and India begin to swell the dialysis population. Finally, water stresses appear most evident in the very regions where dialysis demand is set to exponentially increase.

Current hemodialysis (HD) systems are water-hungry. Global HD is currently almost exclusively provided by single-pass, proportioning dialysis systems paired with low-efficiency reverse osmosis (RO) system water filtration that rejects 60–70% of the presented mains, tank, bore, or well water at the RO system membrane. As about 0.5 liters per minute of dialysis-grade water must be generated for 35:1 proportioning with a chemical concentrate to create dialysis fluid, a total of about 1.5 liters per minute is required to be drawn from the supportive water source. Depending on treatment duration (mean 4 hours per session), RO system efficiency (60–70%), and intertreatment sterilize and rinse phases, the total feed water draw per treatment will approach 500 liters.