Waste liquid incineration using a triple coaxial tube burner in a riser with upper stream is proposed. The effect of hold up of FCC particles on NOx concentration in the burnt gas and conversion of nitrogen in the model waste liquid into NOx is experimentally studied. The experimental results show that the region in which NOx is generated is almost independent of the existence of the particles. However, a rise in the hold up of the particles reduces NOx emission in the exhaust gas. The behavior of the NOx emission can be summarized by applying Fenimore＇s correlation.