1. Overview High-concentration ammonia nitrogen wastewater has a wide range of sources and emissions. Such as fertilizers, coking, petrochemicals, pharmaceuticals, food, landfills, etc., all generate a large amount of high-concentration ammonia nitrogen wastewater. A large amount of ammonia nitrogen wastewater discharged into the water body will not only cause eutrophication of the water body and cause the black odor of the water body, but will also increase the difficulty and cost of water supply treatment, and even have a toxic effect on people and organisms. The impact of ammonia nitrogen wastewater on the environment has attracted attention in the field of environmental protection and around the world. Over the past 20 years, more research has been carried out on ammonia nitrogen wastewater treatment at home and abroad. Its research scope covers various treatment processes of biological and physicochemical methods, such as nitrification and algae cultivation; physical methods include reverse osmosis, distillation, soil irrigation; chemical methods include ion exchange, ammonia blowing, chemical precipitation, vertex chlorination, electrochemical treatment, catalytic cracking, etc. New technologies continue to emerge, showing promising prospects in the application of ammonia nitrogen wastewater treatment. This note focuses on the blow off method widely used by our unit. 2. Technical description The basic principle of the blow-off method is to pass air into the wastewater, so that the dissolved gases and volatile solutes in the wastewater are transferred from the liquid phase to the gas phase, and the process of treating the wastewater is called blowing off. The difference in concentration of the blown material in the liquid phase and the gas phase is the driving force for the transfer from the liquid phase to the gas phase. The basic principle of the blow off method is the theory of gas-liquid phase equilibrium and mass transfer velocity. The blowing method is used to remove ammonia nitrogen from water, that is, the gas passes into the water, so that the gas-liquid fully contacts each other, so that the free ammonia dissolved in the water passes through the gas-liquid interface and transfers to the gas phase, so as to achieve the purpose of removing ammonia nitrogen.