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Recently, the Beijing Fangzhuang Urban Sewage Anaerobic Ammonium Oxidation Project, the world's first short-range nitrification anaerobic ammonium oxidation urban sewage treatment project independently developed, designed, constructed and successfully and stably operated by Beijing Drainage Group, won the 2024 International Water Association (IWA) Project Innovation Awards (PIA) R&D Breakthrough Gold Award. This is the first time that an Asian project has won the IWA Project Innovation Award for R&D Breakthrough since the establishment of the R&D Breakthrough Award.

This technology of treating urban sewage using "red bacteria" can reduce costs while improving effluent quality, promote the recycling of sewage resources and energy, and effectively reduce carbon emissions. In the future, this technology will be further promoted in the field of urban sewage treatment in the city.

Approaching the biological pool of Fangzhuang Wastewater Treatment Plant of Beijing Drainage Group, the brown sewage being treated tumbles out fine bubbles under the action of the aeration device. There is a lifting device at intervals in the biological pool. The staff shakes the handle, and the cable pulls out a square or spherical module carrier from the sewage, with a layer of red bacteria densely attached to the surface. "This is the core of this sewage treatment technology, the anaerobic ammonia oxidizing bacteria that play a role in sewage denitrification, also called 'red bacteria'." said Zhang Shujun, chief scientist of Beijing Drainage Group, senior technical director of the Science and Technology Research and Development Center, and Beijing scholar.

"If the nitrogen in nitrogen-containing wastewater such as urban sewage exceeds the standard and is discharged into the water body, it will cause environmental pollution such as black and smelly water, algal blooms, and red tides. Therefore, denitrification is the key and difficulty of water pollution prevention and control." Zhang Shujun introduced that sewage anaerobic ammonia oxidation is a recognized green and low-carbon sewage denitrification upgrading technology. Compared with traditional biological denitrification processes, anaerobic ammonia oxidation has a short reaction pathway and a fast rate, which can reduce aeration energy consumption, save denitrification agents, reduce sludge production, and reduce greenhouse gas emissions. It is a core key technology for the future in the environmental field and a high-tech tool for achieving the "dual carbon" goal in the sewage treatment field.

Zhang Shujun introduced that the "red bacteria" is a primitive bacterial community that is almost as old as the earth. 100 million of them put together have the same volume as a sesame seed, but they can "eat" ammonia nitrogen pollutants that are 10 times their own weight, and almost no sludge is produced. Using "red bacteria" to treat pollution can effectively solve the problems of black and smelly water, algal blooms, and red tides caused by ammonia nitrogen pollution that are commonly faced in water environment management.

Fangzhuang Wastewater Treatment Plant is the world's first mainstream anaerobic ammonium oxidation project for urban sewage, with a design scale of 7,200 cubic meters per day. Here, after physical treatment such as fine screens, grit chambers, and primary sedimentation tanks, sewage flows into the biological pool for biological treatment. It is at this stage that the "red bacteria" comes into play. Zhang Shujun said that the use of "red bacteria" for denitrification can significantly reduce aeration energy consumption by 60%, and the addition of denitrification agents can save 100%, and minimize sludge production.

The denitrification effect of "red bacteria" is very significant. After being treated with "red bacteria", the sewage in the biological pool flows to the secondary sedimentation tank, where the activated sludge and water can be separated. The water quality of the secondary sedimentation tank is clear, without a trace of odor, with water plants growing in the water and fish swimming happily. "These are the small fish fry we put in before. Now they have grown up, and some have even bred small fish, which also indirectly confirms the effect of sewage treatment." Zhang Shujun said that at present, the Fangzhuang urban sewage anaerobic ammonia oxidation project has achieved stable operation, and the effluent water quality is close to Class IV surface water. When the water temperature is between 11.6℃-28.9℃ and there is no external carbon source and phosphorus removal agent, the average total nitrogen and total phosphorus concentrations of the effluent are 4.21mg/L and 0.22mg/L respectively, and the total nitrogen removal contribution rate of the integrated anaerobic ammonia oxidation zone reaches 78.2%. Compared with traditional sewage treatment processes, the sewage treatment cost of the project is significantly reduced, energy consumption is reduced by more than 40%, and operating costs are reduced by more than 25%.

According to calculations, if all urban sewage treatment plants in Beijing adopt the anaerobic ammonium oxidation process, under the condition of achieving the same effluent quality, it can save 250 million kWh of electricity consumption, 88,000 tons of methanol, 108,000 tons of polyaluminium chloride, reduce 44,000 tons of residual sludge (dry sludge), and reduce carbon dioxide emissions by 162,000 tons each year. In the future, Beijing Drainage Group will continue to improve the sewage treatment capacity of the Fangzhuang project and further promote the application of the "red bacteria" technology to treat urban sewage.

Source: Beijing Daily Client

Reporter: Wang Tianqi

Process Editor: u070