Abstract: Apparatus and methods are disclosed that provide a quasicontinuous thermal regeneration system for ion exchange resins and adsorption media ("matter") as used, for example, in desalinization processes, comprising an operating (desalinization) vessel, means for transferring measured amounts of matter therefrom to successive regeneration and cooling means and recycle back to the operating vessel. Heat exchange means are provided to transfer residual heat from the cooling step to the regeneration step, transport water is recycled in the process with minimal losses, and optional water softening and decarbonizing pre-treatment and chemical post-treatment steps may be included, the latter to remove dirt and heavy metals from the regenerated matter prior to recycle to the operating vessel.