Sanitization of Resins

Peracetic acid, a derivative of hydrogen peroxide, is a good treatment against a wide variety of microbes. Research has shown that peracetic acid will be used to an ever-increasing degree in the field of medicine due to its anti-bacterial, fungicidal, sporicidal and anti-viral action.

Work done by the Degussa Technical Applications Department in conjunction with Chemiewerk Homburg AG determined that peracetic acid is suitable as a disinfectant for deionizers because of its wide spectrum of attack. Using a 0.1% peracetic acid solution in water with a reaction time of one hour, a slime and mold concentration of 104–105/mL was reduced to almost zero. The short rinsing time after using peracetic acid is of importance (typically about 45 minutes or 10–15 BV).

If peracetic acid is used as a disinfectant, the following procedure should be used for both cation and anion resin.  

• Ensure anion resins are fully exhausted as peracetic acid performs best at a pH < 8.

• Make up 1 bed volume (BV) of peracetic acid solution containing 0.1% peracetic acid.

• Inject 1 BV of disinfectant at a flow rate of 5 BV/h (0.6 USGM/ft³) with displacement discharged to a drain approved for chemical waste disposal.

• When all the peracetic acid has been injected, close all valves and retain the disinfectant for at least one hour to soak the resin and pipe work.

• Carry out a displacement rinse using raw water for at least 60 minutes at 5 BV/h, followed by a fast flush for 30 minutes.

• Regenerate the resin once and return the unit to service.