Ion Exchange Systems
This calculation is “fully-burdened” including ongoing operating costs and routine & long-term service requirements. While calculated for a 10 gpm CIX10S, it can be generally applied to all CIX systems. Based upon known CIX operating parameters and typical water & chemical costs, with 24-hour operation 26 days per month at 10 gpm flow with feed water @ 200-ppm TDS.
Labor: Assumed $12 per hour wage and a routine daily operating requirement of 1.5 hour – $468 per month
Electricity: Assumed 460V 3Ph power @ $0.10 per KWH to operate feed & DI Water pumps – $35 per month
Bag Filters: Assumed 2X per week change out of 20-inch 5 micron filters @ $5 each – $40 per month.
Resin Replacement: Conservatively-assumed every 4 years of 5-ft3 cation @ $100/ft3 & anion @ $250/ft3, 1 man-day labor at $150, waste disposal of 2.5 drums @ $150 each; for $2,350 total or $49 per month.
Carbon Replacement: Once per year including 3-ft3 @ $250 & ½ man-day at $75 for $255 total or $27 per month.
Regeneration chemistry: Assumed 2 cation regens per day using 9.8-gal 32% HCl @ $2/gal or $19.60/Day & 3 anion regens per day using 5.1 gal 50% NaOH @ $3/gal or $15.30/day for $39.20/day or $1,019 per month
Wastewater: Assumed 1 carbon backwash/week producing 80-gallons or a total of 320-gallons per month, 3 cation regenerations per day producing 255-gallons or a total of 6,630-gallons per month, and 3 anion regenerations per day producing 285-gallons or a total of 7,410-gallons per month with a combined water/sewer cost of $6/1,000-gallons and treatment costs of $9/1,000-gallons, for a combined cost of $215 per month.
Total Operating Cost: Total estimated operating cost as detailed per above is $1,853 per month.
DI Water Cost: At 10-gpm service 24 hours-per-day/26 days-per-month, 374,400 gallons of rinsewaters would be processed each month with 14,360 gallons lost to backwash & regeneration for a total volume of DI water produced of 359,640. $1,853/359,640=$0.00515 or $5.15 per 1,000 gallons of DI water produced.
Comparison with Alternatives: While every facility is different, the assumed combined cost for wastewater treatment and water/sewer is $15 per 1,000 gallons or nearly 3X rinsewater recycling by ion exchange so for 374,400 gallons per day, the expense for conventional treatment is $5,616 per month. The expense for DI Water from Service DI is typically $50 or more per 1,000-gallons or 10X or more than on-site regenerable ion exchange for a relative monthly expense for SDI of $18,700. Another alternative is Reverse Osmosis (RO) followed by Service DI with an operating cost somewhat less than recycling by ion exchange although “back-end” RO is problematic because of the potential for membrane fouling which greatly increases its need for membrane replacement and overall operating cost.
This calculation was performed by Steven A. Ward, Vice President of Sales for Water Innovations which engineers and markets ion exchange water recycling systems. Steven earned an MPH degree, completed his thesis examining the economics of wastewater treatment in the printed circuit board industry. For more information please contact Sales@waterinnovations.net or by telephone at 760.294.1888 to discuss how this estimate may differ from other applications.
