Persulfate crystals should never be discarded to trash bins. Contact with moisture, contaminants, and/or reducing agents can initiate a chemical reaction or a persulfate decomposition. Persulfate crystals which become a waste material are classified as hazardous waste because they are oxidizers. Persulfates that are spilled on the floor, or otherwise contaminated, are best dissolved in copious quantities of water. 

An acceptable disposal method for spent persulfate solutions is to dilute with large quantities of water and dispose via a treatment system.

Any disposal method must be in full accordance with all local, state and federal regulations.