IFM recently completed design and construction of a double pass reverse osmosis (D.P.R.O.) that will provide the owners a Return on Investment (R.O.I.) in less than 18 months.
The client requires 16.0 Meg ohm quality water for their process. They were employing a single pass R.O. followed by mixed bed deionizers (MB D.I.) to fulfill their needs. The MBDI tanks were in the form of portable exchange, so there was no on-site regeneration.
With a typical city water conductance of 300 microseimens (150 ppm tds), a single pass R.O. produce permeate of 6 to 8 microseimens (3 â€“ 5 ppm). Their daily usage of 200,000 gallons per day resulted in a cubic foot per day demand of 4.6 or 1679 cubic feet per year.
By taking the permeate from the first pass and using this as feed to the second pass, the second pass of this system produced a quality of almost 1 million ohms! The efficiency was also increased by taking the concentrate from the 2nd pass to be part of the feed to the first pass.
By reducing the conductance of the water flowing to the MB DI tanks by over 90%, the client reduced their annual MBDI usage from 1680 cubic feet per year to 168 cubic feet, a savings of over $50,000 per year!