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1) Improve the emission standards for ammonia nitrogen to enhance the level of prevention and control of ammonia nitrogen pollution. Currently, there are 26 existing emission standards for water pollutants in China that set control values for ammonia nitrogen emissions. Overall, among the current national and local emission standards regarding ammonia nitrogen in our country, those established earlier no longer meet the requirements of today’s environmental management practices in those areas ； The local standards issued in recent years are generally sufficient to meet the requirements of local environmental management work. Given the low standards for ammonia nitrogen emissions set for existing industrial enterprises, it is necessary to improve the **environmental quality standard system. Efforts should be intensified to revise industry-specific emission standards, while reducing the scope of application of general and comprehensive emission standards. Emission standards that have been in use for a long time should be thoroughly reviewed and revised, with stricter requirements imposed on ammonia nitrogen emissions. This will encourage enterprises to carry out more thorough treatment measures, thereby improving the level of control over ammonia nitrogen emissions in industry. Given the high concentration of ammonia nitrogen in the wastewater entering industrial wastewater treatment facilities, many enterprises face difficulties in achieving the required standards for ammonia nitrogen levels in the treated water. Moreover, the characteristics of wastewater vary across different industries; therefore, a one-size-fits-all approach should be avoided. Requirements for \"upgrading treatment standards\" should be established based on technical and economic feasibility, taking into account both the requirements regarding water quality and the actual economic capacity and treatment capabilities of various industries. Through \"upgrading standards,\" the transformation and improvement of enterprises will be promoted, and industrial ammonia nitrogen emissions are expected to decrease further. 2) Promote the construction and upgrading of ammonia nitrogen wastewater treatment facilities in towns to significantly enhance the reduction of ammonia nitrogen. Due to factors such as large fluctuations in the volume of incoming water, the impact of industrial wastewater, and high concentrations of SS (solid suspended solids) in the incoming water, the effectiveness of ammonia nitrogen removal in China’s wastewater treatment processes is not satisfactory. The vast majority of wastewater treatment plants in our country lack effective means to control ammonia nitrogen levels. The effectiveness of nitrification largely depends on the natural cycles of spring, summer, autumn, and winter. Some wastewater treatment plants attempt to improve nitrification by simply reducing sludge discharge or increasing aeration volume, but this does not achieve optimal operational results. Some older wastewater treatment plants were not designed to carry out nitrification; they only had the capability to remove COD, which results in high levels of ammonia nitrogen in the wastewater discharged from these plants. The aeration tanks in these wastewater treatment plants have a small volume, failing to meet the sludge age requirements for nitrification ； The sedimentation tank has a relatively small volume, which is not sufficient to accommodate the high sludge concentration required for nitrification ； The aeration equipment has limited capacity and cannot provide the amount of oxygen required for nitrification. By leveraging the synergistic effects of COD reduction in wastewater treatment plants and upgrading these facilities to improve the efficiency of removing ammonia nitrogen from domestic sources, ammonia nitrogen emissions can be effectively reduced. On the one hand, it focuses on tapping potential by improving the load capacity and operational efficiency of existing facilities. Based on the water quality conditions in the watershed, where it is feasible to make modifications, efforts will continue in phases to add nitrogen and phosphorus removal functions to urban sewage treatment plants ； Wastewater treatment plants discharging into enclosed water bodies and areas where there is a direct impact on the water quality of coastal waters should adopt treatment processes with enhanced phosphorus and nitrogen removal capabilities; new wastewater treatment plants are encouraged to use the removal of total nitrogen from water as one of the indicators for pollution control ； For those with a low load rate, improve the sewage collection network and take measures such as network upgrades to increase the load rate. On the other hand, full-scale efforts should be made to build sewage treatment plants in every county, and the development of decentralized sewage treatment facilities in rural areas should be promoted; regions with the necessary resources are encouraged to establish such decentralized facilities according to local conditions. At the same time, efforts to recycle wastewater are being vigorously promoted, with a focus on water-scarce areas; other regions are also encouraged to engage in wastewater recycling, with an emphasis on increasing the rate of wastewater reuse. It should be noted that nitrifying bacteria grow slowly and it is difficult to maintain high biological concentrations; therefore, both sludge return and nitrified liquid return must be carried out simultaneously. During denitrification, carbon sources such as methanol and alkalis often need to be added separately. These issues need to be addressed in a comprehensive manner. Efforts should focus on upgrading existing sewage treatment plants, and companies should be encouraged to adopt technical measures to reduce energy consumption in the sewage treatment process, eliminate outdated technologies, and optimize operations in order to achieve optimal reduction of ammonia nitrogen emissions. 3) By focusing on key industries, efforts should be intensified to adjust the industrial structure and improve the control of industrial pollution. Many industrial wastewater streams have high COD levels; the proportion of COD that is difficult to degrade is high, while readily degradable organic carbon sources account for only about 10% of the total COD. The available carbon sources are not sufficient to meet the requirements for biological nitrogen removal processes, which makes it difficult to ensure that the ammonia nitrogen and total nitrogen levels in the wastewater discharged from treatment plants meet the specified standards. According to the 2007 Annual Report on China’s Environmental Statistics, in 2007 the removal rate of ammonia nitrogen in industrial processes was 60.3%, which was 10 percentage points lower than the removal rate of COD in industrial processes ； The ammonia nitrogen emissions from domestic sources amount to 983,000 tons, with a removal rate of only 26.1%, which is 13 percentage points lower than the removal rate of COD from urban domestic sources ； Based on an analysis of the ammonia nitrogen removal rates in the major industries that generate ammonia nitrogen emissions, except for the petrochemical industry where the removal rate exceeds 90%, all other industries have potential for improvement. The structural issues related to ammonia nitrogen pollution emissions are prominent; the ammonia nitrogen emissions from 8 industries, including chemicals, non-ferrous metals, petrochemicals, agricultural and sideline products, and textiles, account for 85.9% of the total industrial emissions. The chemical industry is the main source of ammonia nitrogen emissions, accounting for over 40% of the total ammonia nitrogen emissions from industrial enterprises. Followed by industries such as papermaking, food processing, textiles, ferrous metallurgy, petrochemicals, and food manufacturing. Industrial sectors with significant problems related to high ammonia nitrogen wastewater emissions include oil refining, fertilizer production, inorganic chemicals, pesticides, ferroalloys, glass manufacturing, as well as food and feed production. Furthermore, the ammonia nitrogen content in wastewater such as that discharged from farms and leachate generated from landfills is also very high. Focusing on key industries such as chemicals, non-ferrous metals, petrochemicals, agricultural and sideline products, and textiles can effectively control the total amount of ammonia nitrogen emissions from industry. Following the approach of first controlling new emissions and then reducing existing stockpiles, strict environmental approval standards are applied at the project approval stage to properly regulate the pace of industry development and economic scale; efforts are made to reduce emissions at the source, thereby controlling the increase in ammonia nitrogen pollutants ； Secondly, strictly enforce **industrial policies** and intensify efforts to adjust the industrial structure; mandatory clean production audits should be carried out on key industries and river basins in accordance with the law, and those that fail to meet the standards for clean production should be shut down or phased out ； Third, focus on end-of-pipe treatment in enterprises, strengthen the supervision of the operation of pollution control facilities, and ensure that industrial enterprises achieve comprehensive and stable compliance with emission standards. 4) Adopt a multi-pronged approach with comprehensive pilot projects to effectively prevent and control pollution from agricultural sources. In some areas, efforts to reduce ammonia nitrogen emissions from industrial point sources and urban domestic sources alone are not sufficient to ensure that all environmental zones meet the required standards. To address the ammonia nitrogen pollution problem at its root, it is necessary to gradually bring under control the ammonia nitrogen pollutants originating from agricultural sources. Due to inadequate foundational work, lack of supervision over projects, difficulties in identifying the entities subject to management, and a shortage of governance mechanisms, agricultural sources will be a key area that requires concerted efforts in water pollution control during the 12th Five-Year Plan period. This is true for COD, and the same holds true for the prevention and control of ammonia nitrogen pollution. At the current stage, agricultural source control should focus on large-scale livestock and poultry farming, by implementing various management systems and policy measures to address pollution control in large-scale livestock and poultry farms (complexes) as well as in areas with high concentrations of free-range livestock and poultry. Large-scale livestock and poultry farming enterprises are managed in accordance with the principles applicable to point sources, under strict requirements, with the goal of ensuring stable emissions that meet the specified ammonia nitrogen standards. For free-range livestock and poultry farms, comprehensive utilization should be the main approach, with the promotion of biological treatment technologies for livestock and poultry manure and the development of ecological agriculture. For the control of agricultural non-point source pollution, management measures are primarily used to prevent problems at their source; where conditions permit, engineering measures are employed as well, with active implementation of pilot projects. By promoting soil testing and fertilization methods, the area dedicated to organic agricultural production can be expanded, thereby reducing the use of chemical fertilizers in agriculture. Promote the research, development, production, transportation, and sales of slow-release/controlled-release fertilizers, improve the structure of fertilizer products, and enhance nitrogen utilization efficiency. Research is being conducted to establish a comprehensive operational model and supply chain that connects large-scale livestock and poultry farms, organic fertilizers, farmers, and farmland, thereby achieving simultaneous reduction of both diffuse and point source pollutants and promoting sustainable agricultural development.