AbstractAntibiotic mycelial dreg (AMD) is one of typical industrial wastes with high moisture and nitrogen contents which are difficult to be dealt with. The previous works demonstrated that the hydrothermal pretreatment is feasible for removing moisture and nitrogen contents from AMD so as to upgrade this waste into solid biofuel. Nevertheless, the NO emission characteristics of its combustion are still unknown and needed to be tested. The present work was aimed to clarify this understanding in a laboratory drop tube reactor under the temperature of 1273K. The raw AMD, the hydrothermally pretreated AMD and coal were respectively supplied into the reactor for combustion. The concentration of NO in the flue gas for different samples were measured and compared to evaluate the emission performance of the fuels. Compared to raw AMD, the NO emission of mono-combustion of hydrothermally pretreated AMD was dramatically reduced, whose reduction rate was above 30%. In order to investigate the mechanism of NO reduction, some analyses using Thermo Gravimetric Analyzer (TGA), X-ray Photoelectron Spectroscopy (XPS) and others were performed to reveal the properties of the raw AMD, hydrothermally pretreated AMD and coal. It was shown that the intermediates produced from releasing volatile maters act as reductants for the reduction of NO. The hydrothermal pretreatment can control the NO emission.