How can ammonia-nitrogen wastewater recycling treatment achieve simultaneous water resource reuse and improve overall recycling rates?
Publish Time: 2025-10-01
In the process of industrial production and urban development, ammonia-nitrogen wastewater has become a significant source of water pollution. Wastewater discharged from industries such as fertilizer, aquaculture, food processing, landfill leachate, and coal chemical industry often contains high concentrations of ammonia-nitrogen. If discharged without proper treatment, it can lead to serious consequences such as eutrophication, decreased dissolved oxygen, and ecosystem imbalance. Traditional treatment methods often rely on biochemical denitrification, converting ammonia-nitrogen into nitrogen gas and releasing it into the atmosphere. While this achieves standard emissions, it wastes resources. With the advancement of the "dual carbon" goals and the concept of a circular economy, resource-based recycling of ammonia-nitrogen wastewater recycling treatment is becoming a new industry trend. A key advantage lies in its ability to not only recover nitrogen resources but also simultaneously reuse water resources, significantly improving overall recycling rates and promoting enterprises' transition to a green and low-carbon future.1. Limitations of Traditional Treatment Models: Resource Loss and Water WasteThe core of traditional biological denitrification processes is "removal," converting ammonia nitrogen into harmless nitrogen gas through the nitrification-denitrification process. This process consumes large amounts of carbon sources and electricity. While the treated effluent can be discharged, it typically still contains certain salts and trace pollutants, making it difficult to directly reuse in high-demand processes. Furthermore, nitrogen, a vital agricultural and industrial raw material, is completely destroyed during the treatment process, resulting in resource waste. More critically, large amounts of treated water are discharged, forcing companies to continuously source fresh water, exacerbating water resource pressures.2. Water Reuse Pathways in Recycling TechnologiesAmmonia-nitrogen wastewater recycling treatment utilizes a "separation + concentration + reuse" approach, removing ammonia nitrogen while maximizing water usability. Its core processes, such as steam stripping, air stripping, membrane absorption, ion exchange, and electrodialysis, all have the potential to achieve water reuse.Take the steam stripping-condensation method as an example: wastewater enters a stripping tower, where high-temperature steam extracts free ammonia from the water. The ammonia is then condensed and absorbed, converting it into high-purity ammonia water or further processing it into ammonium sulfate fertilizer. The ammonia nitrogen concentration in the purified water after deammonification can be reduced to below 10 mg/L, resulting in clear water with only a small amount of inorganic salts. This water can be directly reused in cooling systems, boiler feed water, or as process flush water, achieving in-plant recycling.In membrane absorption technology, hydrophobic hollow fiber membranes separate the wastewater from the absorption liquid. Ammonia gas selectively permeates the membrane pores and is captured by the absorption liquid, forming ammonium sulfate. Water molecules, however, cannot pass through the membrane. As a result, the treated effluent is virtually free of ammonia nitrogen and absorption liquid components, achieving water quality close to that of the original water and increasing its reuse value.In addition, membrane technologies such as electrodialysis and reverse osmosis can be coupled with ammonia nitrogen recovery processes. RO membranes efficiently intercept ammonia nitrogen and other ions, producing water that meets reuse standards. The concentrated water then enters an ammonia nitrogen recovery unit for resource recovery, forming a closed-loop system combining "reduction and concentration + resource recovery."3. Comprehensive Benefits of Improving Overall Recycling RatesBy synergizing ammonia nitrogen recovery with water reuse, enterprises can significantly improve their water resource recycling rates. For example, a livestock wastewater treatment project employs a "pretreatment + stripping + RO reuse" process, achieving an ammonia nitrogen recovery rate exceeding 90%. The produced ammonia water is used in the plant's denitrification system. After RO treatment, 80% of the deammonified water is reused for flushing and cooling, raising the overall water reuse rate to over 75%, significantly reducing fresh water consumption and wastewater discharge.In industrial parks, centralized ammonia nitrogen recovery units can centrally treat high-ammonia wastewater from multiple enterprises. The recovered ammonia water or ammonium sulfate can be sold externally, while the purified water serves as a unified reuse water source for the park, fostering a regional circular economy.Ammonia-nitrogen wastewater recycling treatment is not only a pollution control measure but also an innovative approach to resource recycling and water conservation and efficiency improvement. By using advanced technology to convert ammonia nitrogen into usable resources, high-quality reuse of purified water is achieved, significantly improving the overall recycling rate of water resources.
