Process for treatment of wastewater containing inorganic ammonium salts

A process for treating an aqueous wastewater containing ammonium compounds (46) comprises the steps of preheating a liquid influent (50) and introducing the preheated influent, an oxygen-containing gas and the wastewater (if this is not the liquid influent) into a reaction vessel (54) for undergoing wet oxidation, withdrawing an oxidized effluent from the reaction vessel, the effluent including a gas phase containing ammonia and carbon dioxide and a liquid phase containing the ammonium compounds, reducing the temperature of the effluent to a value sufficient to condense a substantial portion of the ammonia into the liquid phase (68), separating the remaining gas phase containing a substantial portion of the carbon dioxide from the resulting liquid phase (72), adjusting the pH of the liquid phase, either prior to or subsequent to the separation of said remaining gas phase, to a level whereby a substantial portion of the ammonia remains in the liquid phase when the liquid phase is subsequently subjected to an elevated temperature above the boiling point of water, and reducing the water content of the pH-adjusted liquid phase by evaporation (80).