A method and device for realizing simultaneous carbon and phosphorus recovery in deep treatment of municipal sewage by side-flow steel slag fermentation in A-B method
Patent Information
- Application Number
- CN202610952492.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-29
- Publication Date
- 2026-09-25
AI Technical Summary
污泥发酵产物中富含的短链脂肪酸是污水脱氮过程中的优质碳源，但由于经过碱性发酵，污泥释放的氮磷以及污泥脱水性恶化等原因影响了其应用
[0010]综上所述，本发明通过A-B法的独有优势在A段进行碳和磷的捕获，利用钢渣粉进行污泥碱性发酵产生短链脂肪酸（SCFAs）并将产生的磷进行吸附回收，B段通过接种部分A段的污泥快速实现短程硝化同时接种厌氧氨氧化填料进行氮素的去处，同时可以引入部分富含SCFAs的污泥发酵液实现市政污水的深度脱氮除磷同步碳磷回收。本发明通过侧流钢渣发酵以及A-B法工艺的耦合，同时实现市政污水的污染物去除、固体废弃物循环利用以及资源回收，实现污染物去除与资源循环协同增效的目标。
Smart Images
Figure CN122809641A_ABST
Abstract
Description
Technical Field
[0001] This invention designs a method and apparatus for achieving deep treatment of municipal wastewater and simultaneous carbon and phosphorus recovery through AB process using side-flow steel slag fermentation. It belongs to the field of municipal wastewater treatment technology. Specifically, it fully captures carbon and phosphorus in municipal wastewater through AB process, and combines it with sludge fermentation mediated by side-flow steel slag to release carbon sources and recover phosphorus from the remaining sludge. At the same time, it achieves deep and efficient denitrification, phosphorus removal and resource recovery of urban domestic wastewater through anaerobic ammonia oxidation and the introduction of some fermentation products. Background Technology
[0002] Traditional wastewater treatment processes primarily rely on heterotrophic bacteria to remove organic matter in the aerobic stage, aerobic nitrification and anoxic denitrification to remove nitrogen, and anaerobic phosphorus release and aerobic phosphorus uptake, along with the removal of excess sludge to remove phosphorus. The majority of pollutant removal is transferred to the excess sludge, which accumulates 30-50% COD, 15-30% TN, and 90% TP from the wastewater, possessing both pollutant and resource-related attributes. The AB process addresses this by having stage A handle efficient carbon capture, capturing organic matter in the wastewater before oxidation for subsequent energy recovery. Wastewater treated in stage A exhibits a low carbon-to-nitrogen ratio. Stage B then employs new low-carbon technologies to further remove pollutants while reducing carbon emissions and carbon source consumption.
[0003] Sludge fermentation involves controlling the anaerobic fermentation process of sludge at the hydrolysis and acidification stage to accumulate short-chain fatty acids. These fatty acids can be recycled or used directly as a superior carbon source for denitrification in wastewater treatment, achieving sludge reduction and resource utilization. There are many methods to enhance sludge fermentation and acid production, but the simplest and most efficient is to control the pH at 10-11 by adding alkaline reagents and suppressing methanogenic bacteria through a short sludge age (6-8 days), thus accumulating short-chain fatty acids. The short-chain fatty acids abundant in sludge fermentation products are excellent carbon sources for wastewater denitrification; however, their application is limited by the release of nitrogen and phosphorus from the sludge during alkaline fermentation and the deterioration of sludge dewatering properties. Steel slag, a byproduct of steelmaking, mainly consists of residual iron and other steelmaking byproducts. Its RO phase typically results in highly alkaline leachate, potentially polluting soil and posing environmental risks during storage. However, this characteristic of steel slag can be combined with sludge fermentation. The alkalinity released by steel slag can enhance the acid production of sludge fermentation. At the same time, the RO in steel slag has a good adsorption and complexation effect on the phosphorus produced by fermentation. The acid production of sludge mediated by steel slag can realize the simultaneous recovery of short-chain fatty acids and phosphorus elements, and realize the resource utilization and recycling of sludge.
[0004] A method and apparatus for simultaneous carbon and phosphorus recovery in the AB process of municipal wastewater deep treatment via side-flow steel slag fermentation. This method captures organic carbon sources in wastewater using the AB process, releases and accumulates short-chain fatty acids and phosphorus in wastewater and sludge through steel slag-mediated sludge fermentation, and achieves deep nitrogen and phosphorus removal from wastewater through a combination of autotrophic and heterotrophic processes. By controlling microbial operation and coordinating with solid waste management, this approach achieves both "waste-to-waste" treatment and resource and energy recovery from wastewater and sludge, as well as deep wastewater treatment, demonstrating significant advantages in terms of low carbon emissions and high efficiency. Summary of the Invention
[0005] This invention proposes a method and apparatus for achieving simultaneous carbon and phosphorus recovery in the deep treatment of municipal wastewater using the AB process through side-flow steel slag fermentation. By coupling side-flow steel slag fermentation with the AB process, pollutant removal, solid waste recycling, and resource recovery of municipal wastewater can be achieved simultaneously, thus realizing the goal of synergistic efficiency improvement in pollutant removal and resource recycling.
[0006] This invention is mainly achieved through the following technical solutions: Start-up of the waste sludge fermentation tank: The waste sludge fermentation tank (19) is a semi-continuous reactor with a sludge retention time (SRT) of 6-8 days. Initially, waste sludge from the water plant is used for start-up, with the sludge concentration MLSS controlled at 12000-16000 mg / L. The pH value is adjusted to 10±0.2 daily by adding steel slag powder. The steel slag powder is converter steel slag with free calcium oxide <40%, which is ground by a rod mill and magnetically separated to a particle size of less than 200 μm and an iron content of <5%. The waste sludge fermentation tank (19) settles for 2 hours daily, and the sludge fermentation liquid is discharged from the top into the fermentation liquid storage tank (16). After discharging the fermentation liquid, stirring is restarted for 10 minutes before sludge discharge begins, and an equal amount of fresh waste sludge is added at the same time. The discharged waste sludge and steel slag mixture can be used to recover phosphorus resources through incineration or liquid phase extraction.
[0007] Start-up of the A-section phosphorus-rich short-cut nitrification reactor: During the initial start-up of the A-section first-sequence batch reactor (4), mature activated sludge from the wastewater treatment plant is added as seed sludge. The seed sludge is taken from the wastewater treatment plant's excess sludge, and the MLSS concentration of the seed sludge is 3000-4000 mg / L. Actual domestic sewage is used as the influent. The operation adopts an anaerobic-aerobic (AO) mode, with an anaerobic time of 3 hours and an aerobic time of 20 minutes. The dissolved oxygen concentration is maintained at 2.5-3 mg / L. Each cycle includes five stages: influent, anaerobic stirring, aeration, sedimentation, and drainage. The drainage ratio is 50%. No sludge is discharged in the initial stage. Polyphosphate-accumulating bacteria are enriched and cultivated through the AO operation mode to inhibit the occurrence of nitrification. After operating in this mode for more than 7 days, the NH4 in the effluent of the system is reduced. +The system startup is complete when N degradation is <5 mg / L, P <0.5 mg / L, and COD <60 mg / L. At this point, sludge discharge begins each cycle, maintaining a SRT of 14 days. The discharged excess sludge is initially collected as seed sludge for the B-stage startup and later enters the excess sludge fermentation tank for fermentation and phosphorus recovery.
[0008] Start-up of the B-stage short-cut nitrification-anaerobic ammonium oxidation-denitrification integrated reactor (PNAD): In the initial stage of start-up of the B-stage second sequencing batch reactor (5), the residual sludge discharged from the A-stage is used, and the sludge concentration is controlled at 2000-3000 mg / L. The influent uses the drainage from the A-stage and is pumped into the system through the second peristaltic pump (7). The system adopts an aerobic-anoxic (OA) operating mode. First, ammonium oxidizing bacteria (AOB) are enriched, and dissolved oxygen is maintained at 0.5-1 mg / L to ensure that the ammonia nitrogen degradation rate in the aerobic stage reaches more than 50% and to prevent over-aeration. During the ammonium oxidizing bacteria enrichment stage, after the aerobic stage ends, sludge fermentation liquid is pumped into the system through the third peristaltic pump (13) for denitrification to prevent the growth of nitrite oxidizing bacteria (NOB) after obtaining substrate in the next cycle. After the aerobic stage ends, when NH4 + -N and NO2 - When the mass concentration ratio of -N is 1:1 to 1:1.2, there is no NO3 in the system. - -N generation indicates that AOB enrichment is complete. At this time, a fixed packing rack is installed in the system with a packing ratio of 10%. The blank packing rack needs 30-40 days to enrich anaerobic ammonia oxidizing bacteria. Alternatively, the blank packing can be replaced with mature anaerobic ammonia oxidizing packing to accelerate the system startup process. After the anaerobic ammonia oxidizing bacteria are enriched, the OA operating mode is maintained. In the anoxic section, part of the sludge fermentation liquid is pumped in through the third peristaltic pump (13) to simultaneously remove the nitrate nitrogen produced during the anaerobic ammonia oxidation process and the ammonia nitrogen in the sludge fermentation liquid. The system is operated according to the above operating mode until the remaining NH4 in the system is reached in each cycle. + The system is started when -N is less than 1 mg / L and TN is less than 5 mg / L.
[0009] After the reactors in sections A and B are started, they are connected in series and run in a cycle, with two cycles per day: Urban domestic sewage first enters the first sequencing batch reactor (4) of section A for anaerobic stirring for 1.5-2 hours, then the first air compressor (8) is started to aerate section A for 15-20 minutes, with dissolved oxygen maintained at 2.5-3 mg / L. After aeration, sedimentation is carried out for 15 minutes, and the supernatant is discharged to the intermediate water tank (15), with a drainage ratio of 50%. The remaining sludge is discharged from the bottom to the remaining sludge fermentation tank (19), with a remaining sludge discharge rate of 10%. The remaining sludge fermentation tank (19) is allowed to settle for 2 hours daily, and the sludge fermentation liquid is discharged from the top to the fermentation liquid storage tank (16). The sewage in the intermediate water tank is introduced into the second sequencing batch reactor (5) of section B by the second peristaltic pump (7), and then the second air compressor (9) is started to aerate for 1.5-2 hours, with dissolved oxygen maintained at 0.5-1 mg / L. After aeration, anoxic anaerobic ammonia oxidation and deep denitrification are assisted by a third peristaltic pump (13) containing sludge fermentation broth with 100-120 mg / L ammonia nitrogen and 5000-6000 mg / L short-chain fatty acids. The anoxic stirring time is 2.5-3 hours, during which the anaerobic ammonia oxidizing bacteria enriched in the system remove the NH4 introduced from the fermentation broth. + -N and the remaining NO2 in the system - -N and NO3 produced by the reaction - -N is further removed, and NO3 is produced by the anaerobic oxidation of ammonia by denitrifying bacteria. - -N is further removed to achieve deep denitrification of the system. After the anoxic period, the system is allowed to settle for 30 minutes, drain for 15 minutes, and then left idle until the start of the next cycle.
[0010] In summary, this invention leverages the unique advantages of the AB process to capture carbon and phosphorus in stage A. Steel slag powder is used for alkaline fermentation of sludge to produce short-chain fatty acids (SCFAs), and the generated phosphorus is adsorbed and recovered. In stage B, partial inoculation with sludge from stage A rapidly achieves short-cut nitrification while simultaneously inoculating anaerobic ammonia oxidation packing for nitrogen removal. Additionally, a portion of the SCFA-rich sludge fermentation broth can be introduced to achieve deep nitrogen and phosphorus removal from municipal wastewater, with simultaneous carbon and phosphorus recovery. This invention, through the coupling of side-flow steel slag fermentation and the AB process, simultaneously achieves pollutant removal, solid waste recycling, and resource recovery in municipal wastewater, realizing the goal of synergistic efficiency in pollutant removal and resource recycling. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of the structure of the present invention. In the diagram: 1 – PLC process controller; 2 – First agitator; 3 – Third agitator; 4 – First sequencing batch reactor; 5 – Second sequencing batch reactor; 6 – First peristaltic pump; 7 – Second peristaltic pump; 8 – First air compressor; 9 – Second air compressor; 10 – Second agitator; 11 – pH controller; 12 – Temperature controller; 13 – Third peristaltic pump; 14 – Domestic sewage tank; 15 – Intermediate water tank; 16 – Fermentation broth storage tank; 17 – First microporous aeration disc; 18 – Second microporous aeration disc; 19 – Residual sludge fermentation tank. The domestic sewage tank has a volume of 60L, and the fermentation broth storage tank has a volume of 5L and is made of organic plastic. The sequencing batch reactor has an effective volume of 10L and is made of plexiglass.
[0012] Figure 2 The operating mode of each structure. Detailed Implementation
[0013] The patent application will be further explained with reference to the accompanying drawings and examples: such as Figure 1 As shown, this invention includes a PLC process controller, a first agitator, a third agitator, a first sequencing batch reactor (SBR), a second SBR, a first peristaltic pump, a second peristaltic pump, a first air compressor, a second air compressor, a second agitator, a pH controller, a temperature controller, a third peristaltic pump, a domestic sewage tank, an intermediate water tank, a fermentation broth storage tank, a first microporous aeration disc, a second microporous aeration disc, and a waste sludge fermentation tank. The domestic sewage tank and intermediate water tank have a volume of 60L, and the fermentation broth storage tank has a volume of 40L, both made of organic plastic. The effective volume of the SBR and waste sludge fermentation tank is 10L, and they are made of plexiglass.
[0014] The device mainly includes a first sequencing batch reactor (4) in section A, which is connected to a domestic sewage tank (14) via a first peristaltic pump (6). The first sequencing batch reactor (4) is equipped with a first agitator (2) and a first microporous aeration disc (17). The first microporous aeration disc (17) is connected to a first air compressor (8) to aerate the section A system. The effluent from the first sequencing batch reactor (4) in section A enters an intermediate water tank (15). The remaining sludge in section A enters a remaining sludge fermentation tank (19) after sedimentation. The remaining sludge fermentation tank (19) is equipped with a second agitator (10), a pH controller (11), and a temperature controller. The fermentation liquid produced by the fermentation tank (12) and the fermentation tank (19) after fermentation in each cycle enters the fermentation liquid storage tank (16); the second sequencing batch reactor (5) of section B is connected to the intermediate water tank (15) through the second peristaltic pump (7) and to the fermentation liquid storage tank (16) through the third peristaltic pump (13). The second sequencing batch reactor (5) is equipped with a third stirrer (3) and a second microporous aeration disc (18) and a fixed packing frame is installed inside. The second microporous aeration disc (18) is connected to the second air compressor (9) for aeration of section B system. All devices are centrally controlled by PLC process controller (1).
[0015] The urban domestic sewage used in the specific implementation experiment came from a septic tank in a residential area in Chaoyang District, Beijing, with a chemical oxygen demand (COD) of 160-240 mg / L and NH4+ of... + The -N concentration is 45-80 mg / L and the P concentration is 5-10 mg / L, which is typical of domestic sewage with low carbon-nitrogen ratio and low carbon-phosphorus ratio. The excess sludge used for anaerobic fermentation comes from the excess sludge discharged from the reactor daily.
[0016] The specific implementation process is as follows: Start-up of the waste sludge fermentation tank: The waste sludge fermentation tank (19) is a semi-continuous reactor with a sludge retention time (SRT) of 6-8 days. Initially, waste sludge from the water plant is used for start-up, and the sludge concentration MLSS is controlled at 12000-16000 mg / L. The pH value is adjusted to 10±0.2 daily by adding steel slag powder. The steel slag powder is the converter steel slag from the steel plant after pressurized hot quenching. After being ground by a rod mill and magnetically separated, the steel slag powder has a particle size of less than 200 μm. The steel slag powder is the converter steel slag with free calcium oxide <40%. After being ground by a rod mill and magnetically separated, the steel slag powder has a particle size of less than 200 μm and an iron content of <5%. The waste sludge fermentation tank (19) settles for 2 hours daily. The sludge fermentation liquid is discharged from the top and enters the fermentation liquid storage tank (16). After the fermentation liquid is discharged, stirring is restarted for 10 minutes before sludge discharge begins. At the same time, an equal amount of fresh waste sludge is added. The discharged sludge and steel slag mixture can be used to recover phosphorus resources through incineration or liquid phase extraction.
[0017] Start-up of the A-section phosphorus-rich short-cut nitrification reactor: During the initial start-up of the A-section first-sequence batch reactor (4), mature activated sludge from the wastewater treatment plant is added as seed sludge. The seed sludge is taken from the wastewater treatment plant's excess sludge, and the MLSS concentration of the seed sludge is 3000-4000 mg / L. Actual domestic sewage is used as the influent. The operation adopts an anaerobic-aerobic (AO) mode, with an anaerobic time of 3 hours and an aerobic time of 20 minutes. The dissolved oxygen concentration is maintained at 2.5-3 mg / L. Each cycle includes five stages: influent, anaerobic stirring, aeration, sedimentation, and drainage. The drainage ratio is 50%. No sludge is discharged in the initial stage. Polyphosphate-accumulating bacteria are enriched and cultivated through the AO operation mode to inhibit the occurrence of nitrification. After operating in this mode for more than 7 days, the NH4 in the effluent of the system is reduced. + The system startup is complete when N degradation is <5 mg / L, P <0.5 mg / L, and COD <60 mg / L. At this point, sludge discharge begins each cycle, maintaining a SRT of 14 days. The discharged excess sludge is initially collected as seed sludge for the B-stage startup and later enters the excess sludge fermentation tank for fermentation and phosphorus recovery.
[0018] Start-up of the B-stage short-cut nitrification-anaerobic ammonium oxidation-denitrification integrated reactor (PNAD): In the initial stage of start-up of the B-stage second sequencing batch reactor (5), the residual sludge discharged from the A-stage is used, and the sludge concentration is controlled at 2000-3000 mg / L. The influent uses the drainage from the A-stage and is pumped into the system through the second peristaltic pump (7). The system adopts an aerobic-anoxic (OA) operating mode. First, ammonium oxidizing bacteria (AOB) are enriched, and dissolved oxygen is maintained at 0.5-1 mg / L to ensure that the ammonia nitrogen degradation rate in the aerobic stage reaches more than 50% and to prevent over-aeration. During the ammonium oxidizing bacteria enrichment stage, after the aerobic stage ends, sludge fermentation liquid is pumped into the system through the third peristaltic pump (13) for denitrification to prevent the growth of nitrite oxidizing bacteria (NOB) after obtaining substrate in the next cycle. After the aerobic stage ends, when NH4 + -N and NO2 - When the mass concentration ratio of -N is 1:1 to 1:1.2 (NH4) + -N 30±10mg / L, NO2 - -N 36±10mg / L), no NO3 in the system. - -N generation indicates that AOB enrichment is complete. At this time, a fixed packing rack is installed in the system with a packing ratio of 10%. The blank packing rack needs 30-40 days to enrich anaerobic ammonia oxidizing bacteria. Alternatively, the blank packing can be replaced with mature anaerobic ammonia oxidizing packing to accelerate the system startup process. After the anaerobic ammonia oxidizing bacteria are enriched, the OA operating mode is maintained. In the anoxic section, part of the sludge fermentation liquid is pumped in through the third peristaltic pump (13) to simultaneously remove the nitrate nitrogen produced during the anaerobic ammonia oxidation process and the ammonia nitrogen in the sludge fermentation liquid. The system is operated according to the above operating mode until the remaining NH4 in the system is reached in each cycle. +The system is started when -N is less than 1 mg / L and TN is less than 5 mg / L.
[0019] After the reactors in sections A and B are started, they are connected in series and run in a cycle, with two cycles per day: Urban domestic sewage first enters the first sequencing batch reactor (4) of section A for anaerobic stirring for 1.5-2 hours, then the first air compressor (8) is started to aerate section A for 15-20 minutes, with dissolved oxygen maintained at 2.5-3 mg / L. After aeration, sedimentation is carried out for 15 minutes, and the supernatant is discharged to the intermediate water tank (15), with a drainage ratio of 50%. The remaining sludge is discharged from the bottom to the remaining sludge fermentation tank (19), with a remaining sludge discharge rate of 10%. The remaining sludge fermentation tank (19) is allowed to settle for 2 hours daily, and the sludge fermentation liquid is discharged from the top to the fermentation liquid storage tank (16). The sewage in the intermediate water tank is introduced into the second sequencing batch reactor (5) of section B by the second peristaltic pump (7), and then the second air compressor (9) is started to aerate for 1.5-2 hours, with dissolved oxygen maintained at 0.5-1 mg / L. After aeration, anoxic anaerobic ammonia oxidation and deep denitrification are assisted by a third peristaltic pump (13) containing sludge fermentation broth with 100-120 mg / L ammonia nitrogen and 5000-6000 mg / L short-chain fatty acids. The anoxic stirring time is 2.5-3 hours, during which the anaerobic ammonia oxidizing bacteria enriched in the system remove the NH4 introduced from the fermentation broth. + -N and the remaining NO2 in the system - -N and NO3 produced by the reaction - -N is further removed, and NO3 is produced by the anaerobic oxidation of ammonia by denitrifying bacteria. - -N is further removed to achieve deep denitrification of the system. After the anoxic period, the system is allowed to settle for 30 minutes, drain for 15 minutes, and then left idle until the start of the next cycle.
[0020] Experimental results showed that the phosphorus-rich carbon adsorption reactor in section A completed startup in 7-8 days, with a COD removal rate exceeding 60% and a phosphorus removal rate exceeding 95%. High-throughput sequencing revealed that the main polyphosphate-accumulating bacteria in the system were... Ca. AccumulibacterThe abundance reaches over 30%. Section B introduces the excess sludge discharged from Section A to initiate short-cut nitrification, achieving stable nitrification within 3-4 days. The nitrite accumulation rate within the system reaches over 90%. After anaerobic ammonia-oxidizing bacteria complete enrichment / inoculation, a fermentation broth rich in short-chain fatty acids and some ammonia nitrogen is introduced, achieving a total nitrogen removal rate of over 95% in domestic sewage. The system's aeration time is reduced by more than half compared to traditional biological systems. The system exhibits good shock resistance and can achieve deep nitrogen and phosphorus removal from domestic sewage with low carbon-to-nitrogen and carbon-to-phosphorus ratios. Excess sludge discharged from the phosphorus-rich carbon adsorption reactor in Section A is added to the excess sludge fermentation tank daily. Through alkaline fermentation, SCFAs content can accumulate to over 4500-6000 mg / L. Phosphorus is mainly adsorbed and complexed by steel slag and recovered after incineration or liquid-phase extraction. Through the coupling of side-flow steel slag fermentation and the AB process, pollutant removal, solid waste recycling, and resource recovery are simultaneously achieved in municipal sewage, realizing the goal of synergistic efficiency in pollutant removal and resource recycling.
Claims
1. A device for simultaneous carbon and phosphorus recovery in the AB process for deep treatment of municipal wastewater via side-flow steel slag fermentation, characterized in that: The first sequencing batch reactor (4) of section A is connected to the domestic sewage tank (14) via the first peristaltic pump (6). The first sequencing batch reactor (4) is equipped with a first agitator (2) and a first microporous aeration disc (17). The first microporous aeration disc (17) is connected to the first air compressor (8) to aerate the section A system. The effluent from the first sequencing batch reactor (4) of section A enters the intermediate water tank (15). The remaining sludge of section A enters the remaining sludge fermentation tank (19) after sedimentation. The remaining sludge fermentation tank (19) is equipped with a second agitator (10), a pH controller (11), and a temperature controller (12). 2) The fermentation liquid produced by the fermentation tank (19) after fermentation in each cycle enters the fermentation liquid storage tank (16); the second sequencing batch reactor (5) of section B is connected to the intermediate water tank (15) through the second peristaltic pump (7) and to the fermentation liquid storage tank (16) through the third peristaltic pump (13). The second sequencing batch reactor (5) is equipped with a third stirrer (3) and a second microporous aeration disc (18) and a fixed packing frame is installed inside. The second microporous aeration disc (18) is connected to the second air compressor (9) for aeration of section B system. All devices are centrally controlled by PLC process controller (1).
2. A method for simultaneous carbon and phosphorus recovery in AB process municipal wastewater deep treatment using the apparatus described in claim 1. Its features include the following steps: 1) Start-up of the waste sludge fermentation tank: The waste sludge fermentation tank (19) is a semi-continuous reactor with a sludge retention time (SRT) of 6-8 days. Initially, waste sludge from the water plant is used for start-up. The sludge concentration MLSS is controlled at 12000-16000 mg / L. The pH value is adjusted to 10±0.2 by adding steel slag powder daily. The steel slag powder is converter steel slag with free calcium oxide <40%, which is ground by a rod mill and magnetically separated, with a particle size of less than 200μm and an iron content of <5%. The waste sludge fermentation tank (19) settles for 2 hours daily. The sludge fermentation liquid is discharged from the top and enters the fermentation liquid storage tank (16). After the fermentation liquid is discharged, stirring is restarted for 10 minutes before sludge discharge begins. At the same time, an equal amount of fresh waste sludge is added. 2) Start-up of the phosphorus-rich short-cut nitrification reactor in section A: When starting up the first sequencing batch reactor (4) in section A, mature activated sludge from the sewage treatment plant is added as seed sludge. The seed sludge is taken from the excess sludge of the sewage treatment plant, and the MLSS concentration of the seed sludge is 3000-4000 mg / L. The influent is actual domestic sewage. The operation adopts the anaerobic-aerobic (AO) mode, with an anaerobic time of 3 hours and an aerobic time of 20 minutes. The dissolved oxygen concentration is maintained at 2.5-3 mg / L. Each cycle includes five stages: influent, anaerobic stirring, aeration, sedimentation and drainage. The drainage ratio is 50%. No sludge is discharged in the initial stage. Polyphosphate-accumulating bacteria are enriched and cultured through the AO operation mode to inhibit the occurrence of nitrification. After operating in this mode for more than 7 days, the NH4 in the effluent of the system is 3000-4000 mg / L. + When -N degradation is <5mg / L, P <0.5mg / L, and COD <60mg / L, the system is fully started. At this time, sludge discharge begins each cycle, maintaining SRT at 14 days. The discharged excess sludge is initially collected as seed sludge for the start-up of Section B, and later enters the excess sludge fermentation tank for fermentation and phosphorus recovery. 3) Start-up of the B-section short-cut nitrification-anaerobic ammonium oxidation-denitrification integrated reactor (PNAD): In the initial stage of the B-section second sequencing batch reactor (5), the residual sludge discharged from the A-section is used, and the sludge concentration is controlled at 2000-3000 mg / L; the influent is the drainage from the A-section, which is pumped into the system through the second peristaltic pump (7). The system adopts an aerobic-anoxic (OA) operation mode. First, ammonium oxidizing bacteria (AOB) are enriched, and dissolved oxygen is maintained at 0.5-1 mg / L to ensure that the ammonia nitrogen degradation rate in the aerobic section reaches more than 50% and to prevent over-aeration; in the ammonium oxidizing bacteria enrichment stage, after the aerobic section ends, the sludge fermentation liquid is pumped into the system through the third peristaltic pump (13) for denitrification to prevent the growth of nitrite oxidizing bacteria (NOB) after obtaining the substrate in the next cycle; after the aerobic section ends, when NH4 + -N and NO2 - When the mass concentration ratio of -N is 1:1 to 1:1.2, there is no NO3 in the system. - -N generation proves that AOB enrichment is complete; at this time, a fixed packing rack is installed in the system with a packing ratio of 10%; the blank packing rack needs 30-40 days to enrich anaerobic ammonia oxidizing bacteria, or the blank packing can be replaced with mature anaerobic ammonia oxidizing packing to speed up the system startup process; after the anaerobic ammonia oxidizing bacteria are enriched, the OA operation mode is maintained, and part of the sludge fermentation liquid is pumped into the anoxic section through the third peristaltic pump (13) to remove the nitrate nitrogen produced in the anaerobic ammonia oxidation process and the ammonia nitrogen in the sludge fermentation liquid simultaneously; operate according to the above operation mode, and wait until the remaining NH4 in the system in each cycle + The system is started when -N is less than 1 mg / L and TN is less than 5 mg / L; 4) After the reactors in sections A and B are started, they are connected in series and run in a cycle, with two cycles per day: the urban domestic sewage first enters the first sequence batch reactor (4) of section A for anaerobic stirring for 1.5-2 hours, then the first air compressor (8) is started to aerate section A for 15-20 minutes, and the dissolved oxygen is maintained at 2.5-3 mg / L; after aeration, the sedimentation is carried out for 15 minutes, and the supernatant is discharged to the intermediate water tank (15) with a drainage ratio of 50%; the remaining sludge is discharged from the bottom to the remaining sludge fermentation tank (19) with a remaining sludge discharge rate of 10%; the remaining sludge fermentation tank (19) is kept still daily. After settling for 2 hours, the sludge fermentation liquid is discharged from the top to the fermentation liquid storage tank (16); the sewage in the intermediate water tank is introduced into the second sequencing batch reactor (5) of section B by the second peristaltic pump (7), and then the second air compressor (9) is started for aeration for 1.5-2 hours, with dissolved oxygen maintained at 0.5-1 mg / L; after aeration, the sludge fermentation liquid containing 100-120 mg / L ammonia nitrogen and 5000-6000 mg / L short-chain fatty acids is used by the third peristaltic pump (13) to assist in anoxic anaerobic ammonia oxidation and deep denitrification; the anoxic stirring time is 2.5-3 hours, and the anaerobic ammonia oxidizing bacteria enriched in the system remove the NH4 introduced in the fermentation liquid. + -N and the remaining NO2 in the system - -N and NO3 produced by the reaction - -N is further removed, and NO3 is produced by the anaerobic oxidation of ammonia by denitrifying bacteria. - -N is further removed to achieve deep denitrification of the system; after the anoxic period, the system is allowed to settle for 30 minutes, drain water for 15 minutes, and then left idle until the start of the next cycle.