In general we can assume the following:
Municipal or City Treated water contains little or no contaminants that are harmful to drink; therefore, it is unlikely the used resin has any contaminants on it to prevent it from being land filled as ordinary trash.
Well water and untreated surface water supplies may contain contaminants that can remain on the resin after regeneration. These contaminants are usually metals and are found on the cation resin. They may include but are not limited to lead, copper, and arsenic. For more specific information about contaminants we recommend this site.
How to dispose of used ion exchange resin is determined first and foremost by state and local government agencies. Regulations do vary from state to state. To satisfy local regulations it is recommended that you or your environmental manager call your regular waste removal company and ask them what to do. Most likely you will be asked to provide a TCLP test (Toxicity Leachate Characteristic Procedure) for your particular ion exchange resin, see attached pdf file for more specific information about this test.
Most likely the waste removal company will ask for an MSDS on the ion exchange resin you want to throw away. MSDS for most ion exchange resins can be found on this site using the search function.
As part of our rebed service (service to change out spent ion exchange resin or activated carbon) Res-Kem will arrange for proper disposal of spent ion exchange resin or activated carbon on your behalf. This assumes we are providing turnkey removal and installation and the ion exchange resin or activated carbon is purchased from Res-Kem Corp. Sorry, we don't handle hazardous rebed applications.