Title: Cleaning and Sterilization of Ion Exchange resins
The purpose of this presentation is to provide a comprehensive reference guide to cleaning and sterilizing ion exchange resins
How resins get dirty, fouled, and biologically contaminated and the most common types of contamination.
Cleaning techniques and procedures
Sterilizing techniques and procedures
Despite our best efforts, ion exchange resins all too frequently become organically fouled, dirty, coated with precipitants, plugged up with suspended solids, contaminated with various bio-growths, or so broken up that resin fragments interfere with the flow of water through the resin. Although some types of contamination are relatively easily removed, others are more problematic to remove and result in greater cleaning costs than the cost of resin replacement. Worse, some of the chemicals we might like to use to clean resin present issues with worker exposure and/or wastewater disposal.
A second issue with ion exchange resins is their susceptibility to bio fouling. Resin beds are generally good incubators for biological organisms such as bacteria, mold, and even algae. Since we generally dechlorinate IX feedwaters, bio fouling is a common problem. Most cleaning procedures call for bleach, which is ineffective at low doses and damages resin plus reacts with the resin to form harmful byproducts at high doses. Other sterilization products such as peracetic acid can be problematic to rinse out of the resin after use and actually exchange into anion resins. Although hydrogen peroxide can be effective, it also carries risks of over pressurizing and/or overheating the ion exchange vessel and resin. And finally, one of the most effective sterilizing chemicals, chlorine dioxide, is almost never mentioned in discussions about resin sterilization.
Although some resin manufacturers publish basic cleaning and sterilization procedures it may be useful to have a more complete discussion on the subject of resin cleaning. In this admittedly long discussion we tackle both cleaning and sterilization in detail. This information is intended to be a reference guide, irrespective of type of equipment or the manufacture of the ion exchange resin itself.
Peter Meyers, the Technical Director for ResinTech, Inc., has a fascination with ion-exchange that began in high school chemistry class and has never ended. During a career that now spans nearly a half-century, Peter has experienced virtually every aspect ion exchange — from engineering & process design, to field installation, start-up, & troubleshooting. His passion for the “industry that kept [him] gainfully employed all these years” has made him of the industry’s most prolific and sought-after speakers and authors. He has presented around the world on a wide range of ion exchange topics from demineralization, polishing, and softening to industrial process design and operation. Mr. Meyers’ name also appears on 5 U.S. Patents related to ion exchange, including one for ResinTech’s well-known Arsenic-selective media (ASM-10).