Low NOx (deNOxidizer Systems) Thermal Oxidation of nitrogen-bearing wastes require a specialized combustion approach. Single-stage combustion of these wastes can produce NOx emissions in excess of those allowed by most regulatory agencies. To maintain NOx emissions within acceptable limits, Callidus uses a three-stage process to destroy wastes. The waste is burned in the first stage under substoichiometric, or reducing conditions. The high temperatures and lack of oxygen in the first stage cause the nitrogen-bearing compounds to form elemental nitrogen rather than NOx. In the second stage, flue gas from the first stage is cooled to approximately 1400∞F by injection of water, steam or cooled recycled flue gas. The combustion process is completed in stage three where the flue gas is oxidized at a temperature of 1700˚F to 2000˚F with excess oxygen present. NOx in the final flue gas typically ranges from 80 to 200 ppm depending on the waste composition. A destruction efficiency of 99.99 percent can be achieved for most compounds.