A method for disposal of desalination concentrated brine waste product from a desalination process provides that the desalination concentrated brine waste product is injected, along with a carbon dioxide waste product, typically into an imperviously capped porous rock formation, typically including a saline aquifer. The desalination concentrated brine waste product and the carbon dioxide waste product (i.e., which may be injected as a supercritical liquid) may be injected simultaneously or sequentially. The method provides for environmentally acceptable disposal of the desalination concentrated brine waste product and the carbon dioxide waste product.