Ion exchange continues to gain popularity as the method of choice in removing trace contaminants from groundwater and other effluents that must be treated prior to discharge. Generally speaking, these are fairly new and rapidly growing applications.

The number of substances on the EPA’s Maximum Contaminants List (MCL) continues to grow. The MCL levels and purity requirements in all applications are becoming more stringent as our ability to measure lower concentrations of all substances and correlate them with health and production benefits improves. When trace contaminants are to be removed, it is not unusual to have two or more trace contaminants present that are simultaneously removed in a single resin bed. Before simulation technology, there was very little resin performance data available for these kinds of applications.

For some trace ions, the service run lengths of an ion exchange resin are enormous. In these cases, it is more practical to change out the exhausted resins for virgin resins instead of regenerating them. However, in cases where multiple trace contaminants are removed by a single resin bed, the throughput for each contaminant is likely different than for the other(s). In these cases, the resin must either be regenerated or changed out when leakage of the first contaminant reaches its limiting value. In other cases, a contaminant that is present but at levels below discharge limits could be concentrated by the ion exchange resin and then released at excessive concentrations later in the exhaustion cycle.

ResinTech's MIST-X Simulation Technology combines mass action and kinetic relationships to simulate exhaustion and regeneration cycles of most types of ion exchange resin. ResinTech’s Simulation program is designed to deal directly with ionized substances removed by ion exchange resins. It calculates the exhaustion profile for each ion in each portion of the water and the resin bed as the water (or liquid) passes through the resin. Variations in operating conditions can be studied quickly and efficiently. MIST-X provides a (calculated) effluent history for every ionic substance passing through the resin bed. The results are generally displayed graphically, but can also be presented in tabular format. There is virtually no limit to the amount of ions, valences or number of exhaustion and regeneration cycles that can be studied.