Process for treating ammonia-containing exhaust gases

A method for reducing ammonia emissions in combustion exhaust gases and other waste streams using an oxidation catalyst, whereby unreacted ammonia (ammonia "slip") is reduced downstream of a Selective Catalytic Reduction ("SCR") system simultaneously with the reduction of other gaseous pollutants. The invention utilizes a noble metal-based catalyst, such as Pt, Pd or Ru, such that the ammonia is oxidized in the presence of oxygen to a species having a higher oxidation state of nitrogen, preferably elemental nitrogen N2. The efficiency of the process can be increased by optimizing the catalyst operating conditions and adjusting the temperature and space velocity, or the position of the metal-based catalyst relative to the SCR system.