A method for enhancing short-cut denitrification coupled with anaerobic ammonia oxidation reaction efficiency to remove nitrogen and phosphorus

Abstract

The present application belongs to the field of sewage treatment, and particularly relates to a method for enhancing short-cut denitrification coupled with anaerobic ammonia oxidation reaction efficiency to remove nitrogen and phosphorus. The device for removing nitrogen and phosphorus comprises a municipal domestic sewage raw water tank, a nitrate wastewater tank and a short-cut denitrification coupled with anaerobic ammonia oxidation reactor. The present application adds the biochar loaded nano zero-valent iron material into the short-cut denitrification coupled with anaerobic ammonia oxidation reactor, uses the double characteristics of the biochar loaded nano zero-valent iron material, i.e. electron donor and mediator, to improve the denitrification rate, and improves the phosphorus removal efficiency by the precipitation of iron ions and phosphate ions, promotes the growth of anaerobic ammonia oxidation bacteria, improves the contribution rate of anaerobic ammonia oxidation to denitrification, and shortens the system start-up response time. Therefore, the addition of the biochar loaded nano zero-valent iron material is beneficial to the rapid start-up and efficient operation of the short-cut denitrification coupled with anaerobic ammonia oxidation system.

Description

Technical Field

[0001] This invention relates to the field of water pollution control and wastewater treatment technology, and in particular to a method for nitrogen and phosphorus removal that enhances the efficiency of short-cut denitrification coupled with anaerobic ammonia oxidation. Background Technology

[0002] Traditional wastewater treatment processes are based on the activated sludge process. However, the activated sludge process generally requires aeration and chemical dosing, relying on energy and resource inputs, resulting in high energy consumption and carbon emissions. Therefore, it is necessary to innovate wastewater treatment technologies and develop and apply new green and environmentally friendly wastewater treatment technologies.

[0003] In recent years, with the continuous advancement of research on anammox technology, its application in wastewater treatment has gradually become a trend and a promising approach. Currently, short-cut nitrification coupled with anammox has made significant progress, especially in treating side-stream sludge digestate. Despite the great success of side-stream anammox, its mainstream application still faces numerous challenges. Short-cut denitrification, due to its more relaxed and stable operating conditions, has great potential in mainstream wastewater treatment. However, current short-cut denitrification coupled with anammox technology still has some problems: the start-up time is relatively long in practical applications; competition exists between denitrifying bacteria and anammox bacteria in coupled systems, especially integrated systems; anammox contributes little to nitrogen removal; the system's electron transfer efficiency is low; there is a certain demand for external carbon sources; and there are still some greenhouse gas emissions, such as N2O.

[0004] As a widely available and relatively inexpensive carbon-rich material, biochar has been reported to promote denitrification and anaerobic ammonium oxidation processes, showing great potential in wastewater treatment applications. Nano-zero-valent iron can act as an electron donor to replace external carbon sources (such as sodium acetate) to promote denitrification, and the Fe produced during oxidation... 3+ It can also react with phosphate to form precipitates, thus achieving phosphorus removal. However, there are still few reports on the use of biochar and nano-zero-valent iron composite materials to simultaneously achieve high-efficiency nitrogen and phosphorus removal in short-cut denitrification coupled with anaerobic ammonium oxidation systems, significantly shortening response time and saving energy. Summary of the Invention

[0005] To address the problems in existing short-cut denitrification coupled anammox systems, such as competition between denitrifying bacteria and anammox bacteria leading to overgrowth of denitrifying bacteria and thus a low contribution of anammox to nitrogen removal, slow growth of anammox bacteria, and long system start-up response time, as well as other issues like low electron transfer efficiency, reliance on external carbon sources, and lack of phosphorus removal, this invention provides a method for enhancing the nitrogen and phosphorus removal efficiency of short-cut denitrification coupled anammox. This invention utilizes biochar-supported nano-zero-valent iron material to provide an electron donor for the short-cut denitrification coupled anammox system, enhancing electron transfer to improve nitrogen removal efficiency while reducing dependence on external carbon sources, and simultaneously achieving phosphorus removal. The biochar material provides a carrier for microbial growth, improves sludge settling performance, reduces sludge loss, and enhances system stability. Therefore, the addition of biochar-supported nano-zero-valent iron material can promote the application of short-cut denitrification coupled anammox systems in practical engineering.

[0006] The purpose of this invention is to provide a method for nitrogen and phosphorus removal by enhancing short-cut denitrification coupled with anaerobic ammonium oxidation using biochar-supported nano-zero-valent iron materials. The nitrogen and phosphorus removal device utilizing the enhanced efficiency of short-cut denitrification coupled with anaerobic ammonium oxidation includes the following steps:

[0007] S1. Start-up phase: The mixed sludge is placed in the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3; the temperature, dissolved oxygen and pH in the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 are monitored online in real time by the water quality analyzer 5, and a supplementary carbon source is added. After running for a period of time, once the total nitrogen removal rate is stable, only urban domestic sewage is used as the carbon source, and biochar-supported nano-zero-valent iron material is added.

[0008] S2 Operation Phase: Urban domestic sewage and nitrate wastewater are added to the short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor 3, and an external carbon source is added; then anoxic stirring is carried out, without aeration; finally, sedimentation and drainage are carried out. The short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor 3 does not actively discharge sludge, and the supernatant after sedimentation is discharged.

[0009] In some embodiments of the present invention, in step S1, the mixed sludge includes anaerobic ammonia oxidation granular sludge and short-cut denitrification sludge;

[0010] The volume ratio of the anaerobic ammonia oxidation granular sludge to the short-cut denitrification sludge is (3:2) to (3:1).

[0011] In some embodiments of the present invention, in step S1, the concentration of the mixed sludge is 2000~4000 mg / L.

[0012] In some embodiments of the present invention, in step S1, the mass ratio of carbon to iron in the biochar-supported nano-zero-valent iron material is (8~12):1.

[0013] In some embodiments of the present invention, in step S1, the concentration of the biochar-supported nano-zero-valent iron material is 800~2000 mg / L.

[0014] In some embodiments of the present invention, the preparation method of the biochar-supported nano-zero-valent iron material in step S1 is as follows:

[0015] (1) Wash, dry, grind and sieve the biochar (100-200 mesh);

[0016] (2) Dissolve the iron source and the biochar described in step (1) in a solvent, then place them in an ultrasonic cleaner for ultrasonic cleaning and stirring, then add a reducing agent and stir with strong magnetic force to ensure that the growth of nano zero-valent iron is completed. After removing oxygen and allowing it to settle, wash and dry to obtain biochar-supported nano zero-valent iron.

[0017] In some embodiments of the present invention, in step S1, the supplementary carbon source is selected from one or more of sodium acetate, glucose, and methanol;

[0018] The temperature inside the short-path denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor 3 is 24℃~26℃, pH 7.2~7.4, and dissolved oxygen is 0~0.2mg / L.

[0019] In some embodiments of the present invention, in step S1, the total nitrogen removal rate is stabilized when it is >80% and the C / N value is 2~3; the operation period is 30~60 days.

[0020] In some embodiments of the present invention, in step S2, the volume ratio of urban domestic sewage to nitrate wastewater is 0.8:1 to 1.2:1;

[0021] The total amount of urban domestic sewage and nitrate wastewater added is 40-60% of the total effective volume of the short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3).

[0022] In some embodiments of the present invention, during step S2, when stirring in the absence of oxygen, the dissolved oxygen concentration is controlled to be below 0.2 mg / L by a water quality analyzer 5; the sedimentation and drainage time is 10-30 min; and the drainage ratio is 40-60%.

[0023] In some embodiments of the present invention, the nitrogen and phosphorus removal device for enhancing the efficiency of short-cut denitrification coupled with anaerobic ammonium oxidation reaction includes a nitrate wastewater storage tank 1, a domestic sewage storage tank 2, a short-cut denitrification coupled with anaerobic ammonium oxidation nitrogen and phosphorus removal reactor 3, an external carbon source storage tank 4, an online detection system, and an automatic control system.

[0024] The nitrate wastewater storage tank 1 is connected to the first inlet 3.1 of the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 via a first peristaltic pump 1.1. The domestic sewage storage tank 2 is connected to the second inlet 3.2 of the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 via a second peristaltic pump 2.1. The external carbon source storage tank 4 is connected to the third inlet 3.3 of the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 via a third peristaltic pump 4.1. The effluent is discharged through the effluent valve 3.5.

[0025] The short-path denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor 3 is equipped with a first inlet 3.1, a second inlet 3.2, a third inlet 3.3, a first sampling port 3.4, a drain valve 3.5, a second sampling port 3.6, a third sampling port 3.7, a stirrer 7, and an exhaust port 8;

[0026] The online detection system includes a water quality analyzer 5 and an online parameter analyzer host 6; the water quality analyzer 5 is connected to the online parameter analyzer host 6;

[0027] The automatic control system includes a process controller 9 and a computer 10; the process controller 9 is connected to the computer 10 to control the first peristaltic pump 1.1, the second peristaltic pump 2.1, the third peristaltic pump 4.1, the stirrer 7, the drain valve 3.5, the water quality analyzer 5, and the online parameter analyzer host 6 as an online detection system;

[0028] The short-path denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor 3 contains biochar-supported nano-zero-valent iron material.

[0029] The present invention specifically utilizes biochar-supported nano-zero-valent iron materials to enhance short-range denitrification coupled with anaerobic ammonium oxidation for nitrogen and phosphorus removal, as detailed below:

[0030] 1) Material pretreatment: The biochar-supported nano-zero-valent iron material was washed three times with deionized water and anhydrous ethanol respectively, and then dried in a vacuum drying oven.

[0031] 2) System Start-up: Mix anaerobic ammonia oxidation granular sludge and short-cut denitrification sludge in a ratio of 2:1 and inoculate them into the short-cut denitrification coupled anaerobic ammonia oxidation reactor 3 to achieve a sludge concentration of 2000~4000 mg / L. Monitor the temperature, dissolved oxygen, and pH in the reactor online in real time using a water quality analyzer 5. Adjust the room temperature to 24℃~26℃ using air conditioning, control the influent pH to 7.2~7.4, and the dissolved oxygen to 0~0.2 mg / L. During the start-up phase, add sodium acetate as a supplementary carbon source and control the C / N ratio to 2~3. After running for a period of time (30~60 days) until the total nitrogen removal rate stabilizes (>80%), use only domestic sewage as the carbon source and add biochar-supported nano-zero-valent iron material (800~2000 mg / L) to improve the nitrogen and phosphorus removal efficiency of the short-cut denitrification coupled anaerobic ammonia oxidation reactor.

[0032] 3) The operation is as follows:

[0033] 3.1) Wastewater from nitrate wastewater storage tank 1 is pumped into the short-cut denitrification coupled anammox reactor 3 via the first inlet pump 1.1, and wastewater from domestic sewage storage tank 2 is pumped into the reactor via the second inlet pump 2.1. The external carbon source (sodium acetate) in the external carbon source storage tank is pumped into the reactor via the third inlet pump 4.1. The volume ratio of domestic sewage to nitrate wastewater is 1:1, and the influent volume is 50% of the total effective volume of the short-cut denitrification coupled anammox reactor 3. The influent time of the short-cut denitrification coupled anammox reactor 3 is set to 10 min.

[0034] 3.2) After the water intake stage, a 5-hour anoxic mixing stage begins. No aeration is required. During the anoxic mixing stage, the dissolved oxygen concentration is controlled to be below 0.2 mg / L using a water quality analyzer.

[0035] 3.3) After the anoxic stirring stage, the sedimentation and drainage stage begins. The short-cut denitrification coupled anaerobic ammonia oxidation reactor (3) does not actively discharge sludge. The sedimentation time is 10~30 min, the drainage ratio is 50%, and the supernatant after sedimentation is discharged through the drainage valve 3.5.

[0036] The basic principle of this invention, which utilizes biochar-supported nano-zero-valent iron materials to promote nitrogen and phosphorus removal in a short-cut denitrification coupled anaerobic ammonia oxidation reactor, is as follows:

[0037] Nano-sized zero-valent iron exhibits strong reducing activity, providing an electron donor for reducing nitrates in short-pathway denitrification coupled with anaerobic ammonium oxidation (ANO). Biochar itself possesses electron-transfer capabilities and can act as an electron mediator, accelerating electron transfer within the short-pathway denitrification coupled with ANO system. Zero-valent iron can serve as an electron donor for reducing nitrate nitrogen, reducing dependence on external carbon sources. The generated Fe... 3+It can also form precipitates with phosphates, therefore, the addition of biochar-supported nano-zero-valent iron materials can simultaneously promote the denitrification and phosphorus removal efficiency of short-cut denitrification coupled anammox reactors. Meanwhile, the iron ions generated in the system promote the metabolic activity of anammox microorganisms, regulate the activity of key enzymes and the expression of key genes, and promote the secretion of extracellular polymers. Therefore, the addition of biochar-supported nano-zero-valent iron materials is beneficial to the growth of anammox microorganisms and the improvement of anammox efficiency, especially the contribution rate of anammox, in short-cut denitrification coupled anammox systems, thereby shortening the system start-up response time. Furthermore, biochar-supported nano-zero-valent iron materials can also provide a carrier for microbial growth, improve sludge settling performance, reduce sludge loss, and enhance system stability.

[0038] The technical solution of the present invention has the following advantages compared with the prior art:

[0039] (1) The present invention can simultaneously improve the denitrification and phosphorus removal efficiency of short-path denitrification coupled anaerobic ammonia oxidation reactor by adding biochar-supported nano-zero-valent iron material.

[0040] (2) By adding biochar-supported nano-zero-valent iron material, the present invention can reduce the dependence of the short-range denitrification coupled anaerobic ammonia oxidation reactor on external carbon sources, reduce the addition of external carbon sources, and at the same time, the system does not require aeration during operation, thus saving energy and resources from the perspective of energy conservation.

[0041] (3) The present invention improves the growth of anaerobic ammonia oxidation microorganisms and the anaerobic ammonia oxidation effect in the short-range denitrification coupled anaerobic ammonia oxidation system by adding biochar-supported nano-zero-valent iron material, thereby increasing the nitrogen removal contribution rate of anaerobic ammonia oxidation and shortening the system start-up response time.

[0042] (4) The biochar-supported nano-zero-valent iron material provided by the present invention can provide a carrier for microbial growth, improve sludge settling performance, reduce sludge loss in short-range denitrification coupled with anaerobic ammonia oxidation system, and improve system stability. Attached Figure Description

[0043] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0044] Figure 1 This is a schematic diagram of a device that utilizes biochar-supported nano-zero-valent iron materials to enhance the nitrogen and phosphorus removal efficiency of a short-path denitrification coupled anaerobic ammonia oxidation reactor.

[0045] Explanation of reference numerals in the accompanying drawings: 1 is the nitrate wastewater storage tank; 1.1 is the first peristaltic pump; 2 is the domestic sewage storage tank; 2.1 is the second peristaltic pump; 3 is the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor; 3.1 is the first inlet; 3.2 is the second inlet; 3.3 is the third inlet; 3.4 is the first sampling port; 3.5 is the drain valve; 3.6 is the second sampling port; 3.7 is the third sampling port; 4 is the external carbon source storage tank; 4.1 is the third peristaltic pump; 5 is the water quality analyzer; 6 is the online parameter analyzer main unit; 7 is the stirrer; 8 is the exhaust port; 9 is the process controller; 10 is the computer. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0047] The present invention will be further described in detail below through examples:

[0048] 1. The experimental apparatus of the present invention is as follows: Figure 1 As shown, an apparatus for improving the nitrogen and phosphorus removal efficiency of a short-cut denitrification coupled anammox reactor by utilizing biochar-supported nano-zero-valent iron materials includes a nitrate wastewater storage tank 1, a domestic sewage storage tank 2, a short-cut denitrification coupled anammox reactor 3, and an external carbon source storage tank 4. The nitrate wastewater storage tank 1 is connected to the first inlet 3.1 of the short-cut denitrification coupled anammox reactor 3 via a first peristaltic pump 1.1. The domestic sewage storage tank 2 is connected to the second inlet 3.2 of the short-cut denitrification coupled anammox reactor 3 via a second peristaltic pump 2.1. The external carbon source storage tank 4 is connected to the third inlet 3.3 of the short-cut denitrification coupled anammox reactor 3 via a third peristaltic pump 4.1. The effluent is discharged through an outlet valve 3.5. A water quality analyzer 5 is connected to an online parameter analyzer host 6.

[0049] The short-range denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor 3 is equipped with a first inlet 3.1, a second inlet 3.2, a third inlet 3.3, a first sampling port 3.4, a drain valve 3.5, a second sampling port 3.6, a third sampling port 3.7, and an exhaust port 8. In addition, a process controller 9 connected to a computer 10 is provided to control the first peristaltic pump 1.1, the second peristaltic pump 2.1, the third peristaltic pump 4.1, the stirrer 7, the drain valve 3.5, the water quality analyzer 5, and the online parameter analyzer host 6 as an online detection system. The process controller 9 and the computer 10 form an automatic control system.

[0050] 2. The experimental water used in this invention was domestic sewage taken from a residential community, and its water quality was as follows: COD concentration was 130~210 mg / L, NH4+ concentration was...+ -N concentration is 58~80 mg / L, NO2 - -N<=0.5mg / L, NO3 - -N <= 0.5 mg / L, TP concentration is 8~10 mg / L; nitrate wastewater was simulated using laboratory-prepared water, NH4 + -N<=0.5mg / L, NO2 - -N<=0.5mg / L, NO3 - -N concentration was 60 ± 5 mg / L; the test system was as follows: Figure 1 As shown, all reactors are made of plexiglass. The effective volume of the short-cut denitrification coupled anaerobic ammonia oxidation reactor is 8L, and it is well sealed.

[0051] 3. The method for synthesizing the materials involved in this invention:

[0052] (1) Biochar synthesis: Bamboo was ground into powder and then dried in an electric thermostatic drying oven at 105 °C for 24 h. Afterwards, the pre-dried bamboo powder was pyrolyzed in a tube furnace under anaerobic conditions using pure nitrogen instead of air, and dried at 400 °C for 2 h to obtain powder. The obtained powder was sieved to obtain a uniform particle size (20-40 μm), washed three times with deionized water and three times with anhydrous ethanol, and then dried at 105 °C for 24 h to obtain biochar.

[0053] (2) Biochar loaded with nano-zero valent iron: bamboo powder biochar was washed twice with deionized water and then twice with anhydrous ethanol. After drying to constant weight, it was ground and sieved (100 mesh-200 mesh).

[0054] 1.24 g of FeSO4·7H2O and 2 g of washed biochar were dissolved in 150 ml of ethanol-water (ethanol:water = 1:2, v / v) to prepare biochar-supported zero-valent iron nanomaterials. The solution was first ultrasonicated for 30 min in an ultrasonic cleaner, followed by continuous stirring at 300 rpm for 60 min. Then, 50 ml of NaBH4 reducing agent was added to the solution at a rate of 1.5 ml·min. -1 The flow rate was adjusted, and the mixture was stirred for 1 h under strong magnetic stirring (300 rpm) to ensure the complete growth of nano-zero valent iron. After removing oxygen and allowing it to settle, some water was poured off, and the solid particles were washed twice with deoxygenated deionized water, then washed twice with anhydrous ethanol. After that, the solid particles were placed in a vacuum drying oven and dried at 60 °C for 24 h to obtain biochar-supported nano-zero valent iron.

[0055] (3) Synthesis of nano-zero valent iron: 1.24 g FeSO4·7H2O was dissolved in 150 ml ethanol-water (ethanol:water = 1:2, v / v), and then 50 ml NaBH4 reducing agent was added to the solution at a concentration of 1.5 ml·min-1 The flow rate was adjusted, and the mixture was stirred for 1 h under strong magnetic stirring (300 rpm) to ensure the completion of nano-zero valent iron growth. After removing oxygen and allowing it to settle, some water was poured off, and the solid particles were washed twice with deoxygenated deionized water, then washed twice with anhydrous ethanol. After that, the solid particles were placed in a vacuum drying oven and dried at 60 °C for 24 h to obtain nano-zero valent iron.

[0056] Example 1

[0057] This embodiment provides a method for enhancing nitrogen and phosphorus removal in a short-cut denitrification coupled anaerobic ammonium oxidation reactor using biochar-supported nano-zero-valent iron materials. The specific operation is as follows:

[0058] 1) Material pretreatment: Biochar-supported nano-zero-valent iron material with a carbon-to-iron mass ratio of 8:1 was washed three times with deionized water and anhydrous ethanol respectively, and then dried in a vacuum drying oven.

[0059] 2) System Start-up: Anaerobic ammonia oxidation granular sludge and short-cut denitrification sludge are mixed and inoculated into activated sludge at a ratio (sludge dry weight ratio of 2:1) and added to the short-cut denitrification coupled anaerobic ammonia oxidation reactor (SAO reactor 3) to achieve a sludge concentration of 3000 mg / L. The temperature (25℃±1), dissolved oxygen, and pH inside the reactor are monitored online in real time using a water quality analyzer (5). The room temperature is adjusted to 24℃~26℃ using air conditioning, and the influent pH is controlled at 7.2~7.4, with dissolved oxygen at 0~0.2 mg / L. During the start-up phase, sodium acetate is added as a supplementary carbon source, controlling the C / N ratio to 3. After running for a period of time (approximately 30 days), once the total nitrogen removal rate stabilizes (>80%), only domestic sewage is used as the carbon source. Biochar-supported nano-zero-valent iron material (1000 mg / L) is added to improve the nitrogen and phosphorus removal efficiency of the short-cut denitrification coupled anaerobic ammonia oxidation reactor.

[0060] In this embodiment, the urban domestic sewage was taken from the domestic sewage of a certain residential community, and its water quality was as follows: COD concentration was 150 ± 10 mg / L, NH4+ concentration was 10 mg / L. + -N concentration was 60±5 mg / L, NO2 - -N <= 0.5 mg / L, NO3 - -N <= 0.5 mg / L, TP concentration is 8~10 mg / L; nitrate wastewater was simulated using laboratory-prepared water, NH4 + -N<=0.5mg / L, NO2 - -N<=0.5mg / L, NO3 - -N concentration is 60 ± 5 mg / L.

[0061] 3) The operation is as follows:

[0062] 3.1) Wastewater in nitrate wastewater storage tank 1 is pumped into the short-cut denitrification coupled anaerobic ammonium oxidation reactor 3 through the first inlet pump 1.1, and sewage in domestic sewage storage tank 2 is pumped into the reactor through the second inlet pump 2.1. The external carbon source (sodium acetate) in the external carbon source storage tank is fed into the reactor through the third inlet pump 4.1. The volume ratio of domestic sewage to nitrate wastewater is 1:1, the inlet volume is 50% of the total effective volume of the short-cut denitrification coupled anaerobic ammonium oxidation reactor 3, and the inlet time of the short-cut denitrification coupled anaerobic ammonium oxidation reactor 3 is set to 10 min.

[0063] 3.2) After the water intake stage, a 5-hour anoxic stirring stage is entered. During the anoxic stirring stage, the dissolved oxygen concentration is controlled to be below 0.2 mg / L using a water quality analyzer.

[0064] 3.3) After the anoxic stirring stage, the sedimentation and drainage stage begins. The short-cut denitrification coupled anaerobic ammonia oxidation reactor (3) does not actively discharge sludge. The sedimentation time is 20 min and the drainage ratio is 50%. The supernatant after sedimentation is discharged through the drainage valve (3.5).

[0065] Detecting NH4 in the final discharged water + -N, NO3 - The contents of -N, TN, and TP, as well as the contribution rate of anaerobic ammonia oxidation denitrification and the system start-up response time, are shown in Table 1.

[0066] Comparative Example 1 (Biochar alone)

[0067] Similar to Example 1, the difference is that the biochar-supported nano-zero-valent iron material was replaced with an equal amount of biochar. The experimental results are shown in Table 1.

[0068] Comparative Example 2 (Using nano-zero valent iron alone)

[0069] Similar to Example 1, the difference is that only nano-zero valent iron of the same mass as the iron contained in the biochar-supported nano-zero valent iron material was added. The experimental results are shown in Table 1.

[0070] Comparative Example 3

[0071] Similar to Example 1, except that no materials were added. The experimental results are shown in Table 1.

[0072] Table 1

[0073]

[0074] As shown in Table 1, the reactor using biochar-supported nano-zero-valent iron materials has the best operating performance and the fastest system start-up.

[0075] Therefore, the device and method of the present invention, which utilizes biochar-supported nano-zero-valent iron materials to enhance nitrogen and phosphorus removal in a short-cut denitrification / anaerobic ammonium oxidation system, facilitates the rapid start-up and efficient operation of the short-cut denitrification coupled anaerobic ammonium oxidation system, promotes the application of the nitrogen and phosphorus removal efficiency process of the short-cut denitrification coupled anaerobic ammonium oxidation reactor in wastewater treatment, and can be applied to the denitrification of nitrate wastewater and municipal sewage.

[0076] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for nitrogen and phosphorus removal using biochar-supported nano-zero-valent iron materials to enhance short-range denitrification coupled with anaerobic ammonium oxidation, characterized in that, A nitrogen and phosphorus removal unit utilizing enhanced short-cut denitrification coupled with anaerobic ammonia oxidation includes the following steps: S1. Start-up stage: The mixed sludge is placed in the short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3); the temperature, dissolved oxygen and pH in the short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3) are monitored online in real time by a water quality analyzer (5), and a supplementary carbon source is added. After running for a period of time, when the total nitrogen removal rate is stable, only urban domestic sewage is used as the carbon source, and biochar-loaded nano zero-valent iron material is added. S2 Operation Stage: Urban domestic sewage and nitrate wastewater are added to the short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3), and an external carbon source is added; then anoxic stirring is carried out without aeration; finally, sedimentation and drainage are carried out. The short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3) does not actively discharge sludge, and the supernatant after sedimentation is discharged. In step S1, the mixed sludge includes anaerobic ammonia oxidation granular sludge and short-cut denitrification sludge; the temperature in the short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3) is 24℃~26℃, the pH is 7.2~7.4, and the dissolved oxygen is 0~0.2mg / L.

2. The method according to claim 1, characterized in that, The volume ratio of the anaerobic ammonia oxidation granular sludge to the short-cut denitrification sludge is (3:2) to (3:1).

3. The method according to claim 1, characterized in that, In step S1, the concentration of the mixed sludge is 2000~4000 mg / L.

4. The method according to claim 1, characterized in that, In step S1, the concentration of the biochar-supported nano-zero valent iron material is 800~2000 mg / L; the mass ratio of carbon to iron in the biochar-supported nano-zero valent iron material is (8~12):

1.

5. The method according to claim 1, characterized in that, In step S1, the supplementary carbon source is selected from one or more of sodium acetate, glucose, and methanol.

6. The method according to claim 1, characterized in that, In step S1, the total nitrogen removal rate is considered to be stable when it is >80% and the C / N ratio is 2~3; the operation period is 30~60 days.

7. The method according to claim 1, characterized in that, In step S2, the volume ratio of urban domestic sewage to nitrate wastewater is (0.8:1) to (1.2:1). The total amount of urban domestic sewage and nitrate wastewater added is 40-60% of the total effective volume of the short-cut denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3).

8. The method according to claim 1, characterized in that, In step S2, during the anoxic stirring, the dissolved oxygen concentration is controlled to be below 0.2 mg / L using a water quality analyzer (5); the sedimentation and drainage time is 10-30 min; and the drainage ratio is 40-60%.

9. The method according to claim 1, characterized in that, The nitrogen and phosphorus removal device for enhancing the efficiency of short-cut denitrification coupled with anaerobic ammonium oxidation includes a nitrate wastewater storage tank (1), a domestic sewage storage tank (2), a short-cut denitrification coupled with anaerobic ammonium oxidation nitrogen and phosphorus removal reactor (3), an external carbon source storage tank (4), an online detection system, and an automatic control system. The nitrate wastewater storage tank (1) is connected to the first inlet (3.1) of the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) via a first peristaltic pump (1.1). The domestic sewage storage tank (2) is connected to the second inlet (3.2) of the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) via a second peristaltic pump (2.1). The external carbon source storage tank (4) is connected to the third inlet (3.3) of the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) via a third peristaltic pump (4.1). The effluent is discharged through a drain valve (3.5). The short-path denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3) is equipped with a first inlet (3.1), a second inlet (3.2), a third inlet (3.3), a first sampling port (3.4), a drain valve (3.5), a second sampling port (3.6), a third sampling port (3.7), a stirrer (7), and an exhaust port (8); The online detection system includes a water quality analyzer (5) and an online parameter analyzer host (6); the water quality analyzer (5) is connected to the online parameter analyzer host (6); The automatic control system includes a process controller (9) and a computer (10); the process controller (9) is connected to the computer (10) to control the first peristaltic pump (1.1), the second peristaltic pump (2.1), the third peristaltic pump (4.1), the stirrer (7), the drain valve (3.5), and the water quality analyzer (5) and the online parameter analyzer host (6) form an online detection system; The short-path denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor (3) contains biochar-supported nano-zero-valent iron material.

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