Method for nitrogen and phosphorus removal by enhancing short-cut denitrification coupling anaerobic ammonia oxidation reaction efficiency

Abstract

The invention belongs to the field of sewage treatment, and particularly relates to a nitrogen and phosphorus removal method for enhancing short-cut denitrification coupling anaerobic ammonia oxidation reaction efficiency. The nitrogen and phosphorus removal device comprises an urban domestic sewage raw water tank, a nitrate wastewater tank and a short-cut denitrification coupling anaerobic ammonia oxidation reactor. According to the invention, the biochar-loaded nano zero-valent iron material is added into the short-cut denitrification coupled anaerobic ammonia oxidation reactor, and the biochar-loaded nano zero-valent iron material has dual characteristics of electron donors and mediators, so that the nitrogen removal rate is increased, and the phosphorus removal efficiency is improved through the precipitation effect of iron ions and phosphate ions; in addition, the growth of anaerobic ammonium oxidation bacteria is promoted, the contribution rate of anaerobic ammonium oxidation to denitrification is increased, and the starting response time of the system is shortened. Therefore, the addition of the charcoal-loaded nano zero-valent iron material is beneficial to quick start and efficient operation of the short-cut denitrification coupled anaerobic ammonia oxidation system.

Description

Technical Field

[0001] The invention relates to the technical field of water pollution control and sewage treatment, and in particular to a method for denitrification and phosphorus removal by enhancing the efficiency of short-range denitrification coupled with anaerobic ammonium oxidation reaction. Background Art

[0002] Traditional sewage treatment technology is developed based on the activated sludge method. However, the activated sludge method generally requires aeration and dosing, and relies on energy and resource input, resulting in high energy consumption and carbon emissions. Therefore, it is necessary to innovate sewage treatment technology and develop and apply new green and environmentally friendly sewage treatment technology.

[0003] In recent years, with the continuous advancement of anaerobic ammonium oxidation technology research, the application of anaerobic ammonium oxidation process to treat sewage has gradually become a trend and a promising approach. At present, the short-term nitrification coupled anaerobic ammonium oxidation process has made a lot of progress, especially in the treatment of sidestream sludge digestate. Although sidestream anaerobic ammonium oxidation has achieved great success, the application of mainstream anaerobic ammonium oxidation still faces many challenges. Short-term denitrification has great potential in the application of mainstream sewage treatment due to its advantages of more relaxed and more stable operating conditions. However, there are still some problems in the short-term denitrification coupled anaerobic ammonium oxidation process technology: the short-term denitrification coupled anaerobic ammonium oxidation process has a long start-up time in actual application, in the short-term denitrification and anaerobic ammonium oxidation coupling system, especially the integrated coupling system, there is competition between denitrifying bacteria and anaerobic ammonium oxidizing bacteria, the contribution rate of anaerobic ammonium oxidation in denitrification is not high, the system electron transfer efficiency is low, there is a certain demand for external carbon sources, and there is still a certain emission of greenhouse gases 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 and has great potential in wastewater treatment applications. Nano-zero-valent iron can be used as an electron donor to replace external carbon sources (such as sodium acetate) to promote denitrification and oxidize the Fe 3+ It can also react with phosphate to form precipitation to achieve phosphorus removal. However, in a short-range denitrification coupled anaerobic ammonia oxidation system, there are still few reports on the use of biochar and nano zero-valent iron composite materials to simultaneously achieve efficient nitrogen and phosphorus removal, significantly shorten the response time and save energy. Summary of the invention

[0005] In order to solve the problem that in the short-range denitrification coupled anaerobic ammonium oxidation system in the prior art, there is competition between denitrifying bacteria and anaerobic ammonium oxidizing bacteria, which leads to excessive growth of denitrifying bacteria, so that the contribution rate of anaerobic ammonium oxidation in denitrification is not high, the growth of anaerobic ammonium oxidizing bacteria is slow, and the system startup response time is long. In addition, the short-range denitrification coupled anaerobic ammonium oxidation system also has low electron transfer efficiency, certain demand for external carbon sources, and no consideration of phosphorus removal. Therefore, the present invention provides a method for denitrification and phosphorus removal that enhances the efficiency of short-range denitrification coupled anaerobic ammonium oxidation reaction. The present invention provides an electron donor for the short-range denitrification coupled anaerobic ammonium oxidation system by adding biochar-loaded nano zero-valent iron materials, and strengthens electron transfer to reduce dependence on external carbon sources while improving denitrification efficiency, and can take into account phosphorus removal. Biochar materials can provide carriers for microbial growth, improve sludge settling performance, reduce sludge loss, and improve system stability. Therefore, the addition of biochar-loaded nano zero-valent iron materials can promote the application of short-range denitrification coupled anaerobic ammonium oxidation systems in practical engineering.

[0006] The purpose of the present invention is to provide a method for denitrification and phosphorus removal by using biochar loaded nano zero-valent iron material to strengthen short-range denitrification coupled with anaerobic ammonium oxidation reaction, and a denitrification and phosphorus removal device using the enhanced short-range denitrification coupled with anaerobic ammonium oxidation reaction efficiency, comprising the following steps:

[0007] S1, startup stage: placing the mixed sludge in the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3; and monitoring the temperature, dissolved oxygen and pH in the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 in real time online through the water quality online detector 5, adding a supplementary carbon source, and running for a period of time. After the total nitrogen removal rate is stable, only urban domestic sewage is used as a carbon source, and biochar-loaded nano zero-valent iron material is added;

[0008] S2 operation stage: add urban domestic sewage and nitrate wastewater into the short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3, and add an external carbon source; then perform anoxic stirring without aeration; finally, perform sedimentation and drainage, the short-range denitrification coupled anaerobic ammonium 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 ammonium oxidation granular sludge and short-cut denitrification sludge;

[0010] The volume ratio of the anaerobic ammonium 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-loaded 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-loaded nano zero-valent iron material is 800-2000 mg / L.

[0014] In some embodiments of the present invention, in step S1, the method for preparing the biochar-loaded nano zero-valent iron material is:

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

[0016] (2) dissolving the iron source and the biochar described in step (1) in a solvent, and then placing them in an ultrasonic cleaning machine for ultrasonication and stirring, and then adding a reducing agent and performing strong magnetic stirring to ensure that the growth of nano zero-valent iron is complete, removing oxygen, allowing the nano zero-valent iron to stand and precipitate, and then washing and drying to obtain biochar-loaded 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 in the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 is 24° C. to 26° C., the pH is 7.2 to 7.4, and the dissolved oxygen is 0 to 0.2 mg / L.

[0019] In some embodiments of the present invention, in step S1, the total nitrogen removal rate is stabilized, which means >80%, and the C / N value is 2-3; and 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-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3).

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

[0023] In some embodiments of the present invention, the denitrification and phosphorus removal device for enhancing the efficiency of the short-range denitrification coupled anaerobic ammonium oxidation reaction comprises a nitrate wastewater storage tank 1, a domestic sewage storage tank 2, a short-range denitrification coupled anaerobic ammonium oxidation denitrification 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 water inlet 3.1 of the short-distance denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 through the first peristaltic pump 1.1, and the domestic sewage storage tank 2 is connected to the second water inlet 3.2 of the short-distance denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 through the second peristaltic pump 2.1; the external carbon source storage tank 4 is connected to the third water inlet 3.3 of the short-distance denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 through the third peristaltic pump 4.1, and the outlet water is discharged through the outlet valve 3.5;

[0025] The short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 is provided with a first water inlet 3.1, a second water inlet 3.2, a third water 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 meter 5 and an online parameter meter host 6; the water quality meter 5 is connected to the online parameter meter 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 meter 5 and the online parameter meter host 6 to form an online detection system;

[0028] Biochar-loaded nano zero-valent iron material is placed in the short-range denitrification-coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 .

[0029] The specific method of the present invention for removing nitrogen and phosphorus by using biochar loaded nano zero-valent iron material to strengthen short-range denitrification coupled with anaerobic ammonium oxidation reaction is as follows:

[0030] 1) Material pretreatment: The biochar-loaded 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) Start-up system: The anaerobic ammonium oxidation granular sludge and the short-cut denitrification sludge are mixed and inoculated into the short-cut denitrification coupled anaerobic ammonium oxidation reactor 3 in a ratio of (2:1) to make the sludge concentration 2000-4000 mg / L, and the temperature, dissolved oxygen and pH in the reactor are monitored online in real time by the water quality online detector 5; the room temperature is adjusted to 24°C-26°C by air conditioning, the influent pH is controlled to 7.2-7.4, and the dissolved oxygen is controlled to 0-0.2 mg / L. Sodium acetate is added as a supplementary carbon source in the startup stage, and the C / N is controlled to 2-3. After running for a period of time (30-60 days), only domestic sewage is used as a carbon source after the total nitrogen removal rate is stable (>80%), and biochar-loaded nano zero-valent iron material (800-2000 mg / L) is added to improve the denitrification and phosphorus removal efficiency of the short-cut denitrification coupled anaerobic ammonium oxidation reactor.

[0032] 3) The operation is as follows:

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

[0034] 3.2) After the water inlet stage, a 5-hour anoxic stirring stage begins. No aeration is required. During the anoxic stirring stage, the dissolved oxygen concentration is controlled below 0.2 mg / L by an online water quality detector 5;

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

[0036] The basic principle of using biochar loaded nano zero-valent iron materials to promote short-range denitrification coupled with anaerobic ammonium oxidation reactors for nitrogen and phosphorus removal is:

[0037] Nano-zero-valent iron has a strong reducing activity and can provide electron donors for the short-range denitrification coupled anaerobic ammonium oxidation system to reduce nitrate. Biochar itself has the ability to transfer electrons and can act as an electron mediator to accelerate the electron transfer in the short-range denitrification coupled anaerobic ammonium oxidation system. Zero-valent iron can act as an electron donor to reduce nitrate nitrogen, reducing the dependence on external carbon source addition. The Fe 3+It can also form precipitation with phosphate, so the addition of biochar-loaded nano zero-valent iron materials can simultaneously promote the denitrification and phosphorus removal efficiency of the short-range denitrification coupled anaerobic ammonium oxidation reactor. At the same time, the iron ions produced in the system have the functions of promoting the metabolic activity of anaerobic ammonium oxidizing microorganisms, regulating the activity of key enzymes and the expression of key genes, and promoting the secretion of extracellular polymers. Therefore, the addition of biochar-loaded nano zero-valent iron materials is beneficial to the growth of anaerobic ammonium oxidizing microorganisms and the anaerobic ammonium oxidation effect in the short-range denitrification coupled anaerobic ammonium oxidation system, especially the improvement of the anaerobic ammonium oxidation contribution rate, thereby shortening the system startup response time. In addition, biochar-loaded nano zero-valent iron materials can also provide a carrier for microbial growth, which can improve sludge settling performance, reduce sludge loss, and improve system stability.

[0038] The above 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 a short-range denitrification coupled anaerobic ammonium oxidation reactor by adding biochar-loaded nano zero-valent iron material.

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

[0041] (3) The present invention adds biochar loaded nano zero-valent iron material, which is beneficial to the growth of anaerobic ammonium oxidizing microorganisms and the improvement of anaerobic ammonium oxidation effect in the short-range denitrification coupled anaerobic ammonium oxidation system, thereby improving the denitrification contribution rate of anaerobic ammonium oxidation and shortening the system startup response time.

[0042] (4) The biochar-loaded nano-zero-valent iron material provided by the present invention can provide a carrier for microbial growth, improve sludge settling performance, and the short-range denitrification coupled anaerobic ammonia oxidation system can reduce sludge loss and improve system stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0044] Figure 1 The schematic diagram of the device structure is a device that utilizes biochar loaded nano zero-valent iron materials to promote the denitrification and phosphorus removal efficiency of a short-range denitrification coupled anaerobic ammonium oxidation reactor;

[0045] Description of the accompanying drawings: 1 is a nitrate wastewater storage tank, 1.1 is a first peristaltic pump, 2 is a domestic sewage storage tank, 2.1 is a second peristaltic pump, 3 is a short-range denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor, 3.1 is a first water inlet, 3.2 is a second water inlet, 3.3 is a third water inlet, 3.4 is a first sampling port, 3.5 is a drain valve, 3.6 is a second sampling port, 3.7 is a third sampling port, 4 is an external carbon source storage tank, 4.1 is a third peristaltic pump, 5 is a water quality meter, 6 is an online parameter meter host, 7 is a stirrer, 8 is an exhaust port, 9 is a process controller, and 10 is a computer. DETAILED DESCRIPTION

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

[0047] The present invention is further described in detail below by way of examples:

[0048] 1. The experimental device of the present invention is as follows Figure 1 As shown, a device for promoting the denitrification and phosphorus removal efficiency of a short-range denitrification coupled anaerobic ammonium oxidation reactor by using biochar-loaded nano zero-valent iron materials comprises a nitrate wastewater storage tank 1, a domestic sewage storage tank 2, a short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3, and an external carbon source storage tank 4; the nitrate wastewater storage tank 1 is connected to the first water inlet 3.1 of the short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 through a first peristaltic pump 1.1, the domestic sewage storage tank 2 is connected to the second water inlet 3.2 of the short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 through a second peristaltic pump 2.1, the external carbon source storage tank 4 is connected to the third water inlet 3.3 of the short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor 3 through a third peristaltic pump 4.1, the effluent is discharged through an outlet valve 3.5, and a water quality meter 5 is connected to an online parameter meter host 6;

[0049] The short-range denitrification coupled anaerobic ammonia oxidation denitrification and phosphorus removal reactor 3 is provided with a first water inlet 3.1, a second water inlet 3.2, a third water 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 agitator 7, the drain valve 3.5, the water quality meter 5 and the online parameter meter host 6 as an online detection system, and the process controller 9 and the computer 10 are an automatic control system.

[0050] 2. The domestic sewage used in the test water of the present invention was taken from the domestic sewage of a certain community, and its water quality is as follows: COD concentration is 130-210 mg / L, NH4+ -N concentration is 58~80mg / L, NO 2- -N<=0.5mg / L, NO3 - -N<=0.5mg / L, TP concentration is 8~10mg / L; nitrate wastewater is simulated by laboratory water distribution, NH4 + -N<=0.5mg / L, NO 2- -N<=0.5mg / L, NO 3- -N concentration is 60±5mg / L; the test system is as follows Figure 1 As shown, each reactor is made of plexiglass, and the effective volume of the short-range denitrification coupled anaerobic ammonium oxidation reactor is 8L and is well sealed.

[0051] 3. Synthesis method of materials involved in the present invention:

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

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

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

[0056] Example 1

[0057] This embodiment provides a method for strengthening the denitrification and phosphorus removal of a short-range denitrification coupled anaerobic ammonium oxidation reactor by using biochar loaded nano zero-valent iron material. The specific operation is as follows:

[0058] 1) Material pretreatment: The biochar-loaded nano-zero-valent iron material with a carbon-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) Start the system: the anaerobic ammonium oxidation granular sludge and the short-cut denitrification sludge are mixed and inoculated into the activated sludge in proportion (the sludge dry weight ratio is 2:1), and added to the short-cut denitrification coupled anaerobic ammonium oxidation reactor, so that the sludge concentration of the short-cut denitrification coupled anaerobic ammonium oxidation reactor 3 is 3000 mg / L, and the temperature (25°C ± 1), dissolved oxygen and pH in the reactor are monitored online in real time by the water quality online detector 2.3; the room temperature is adjusted to 24°C ~ 26°C by air conditioning, the influent pH is controlled to 7.2 ~ 7.4, and the dissolved oxygen is 0 ~ 0.2 mg / L. Sodium acetate is added as a supplementary carbon source in the startup stage, and the C / N is controlled to 3. After running for a period of time (about 30 days), only domestic sewage is used as a carbon source after the total nitrogen removal rate is stable (> 80%), and biochar-loaded nano zero-valent iron material (1000 mg / L) is added to improve the denitrification and phosphorus removal efficiency of the short-cut denitrification coupled anaerobic ammonium oxidation reactor;

[0060] In this example, the urban domestic sewage was taken from a residential area, and its water quality was as follows: COD concentration was 150±10mg / L, NH4 + -N concentration is 60±5mg / L, NO 2- -N<=0.5mg / L, NO 3- -N<=0.5mg / L, TP concentration is 8~10mg / L; nitrate wastewater is simulated by laboratory water distribution, NH4 + -N<=0.5mg / L, NO 2- -N<=0.5mg / L, NO 3- -N concentration is 60±5mg / L.

[0061] 3) The operation is as follows:

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

[0063] 3.2) After the water inlet stage, the anoxic stirring stage is entered for 5 hours. During the anoxic stirring stage, the dissolved oxygen concentration is controlled to be below 0.2 mg / L by an online water quality detector (5);

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

[0065] Detection of NH4 in the final discharged water + -N, NO 3- The experimental results of -N, TN, TP contents, anaerobic ammonium oxidation denitrification contribution rate, and system startup response time are shown in Table 1.

[0066] Comparative Example 1 (using biochar alone)

[0067] The same as Example 1, the difference is that the biochar-loaded nano zero-valent iron material is 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] The same as Example 1, except that only nano zero-valent iron of the same mass as the iron contained in the biochar-loaded nano zero-valent iron material is added. The experimental results are shown in Table 1.

[0070] Comparative Example 3

[0071] The same as Example 1, except that no material is added. The experimental results are shown in Table 1.

[0072] Table 1

[0073]

[0074] It can be seen from Table 1 that the reactor using biochar loaded with nano zero-valent iron material has the best operating effect and the fastest system startup.

[0075] Therefore, the device and method of the present invention for strengthening the denitrification and phosphorus removal of the short-range denitrification / anaerobic ammonium oxidation system by using biochar-loaded nano zero-valent iron materials is conducive to the rapid startup and efficient operation of the short-range denitrification coupled anaerobic ammonium oxidation system, promotes the application of the short-range denitrification coupled anaerobic ammonium oxidation reactor denitrification and phosphorus removal efficiency process in sewage treatment, and can be applied to the denitrification of nitrate wastewater and urban sewage.

[0076] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for denitrification and phosphorus removal by using biochar loaded nano zero-valent iron material to strengthen short-range denitrification coupled with anaerobic ammonium oxidation reaction, characterized in that: The denitrification and phosphorus removal device using enhanced short-range denitrification coupled with anaerobic ammonium oxidation reaction efficiency comprises the following steps: S1, startup phase: placing the mixed sludge in a short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3); and using a water quality online detector (5) to monitor the temperature, dissolved oxygen and pH in the short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) in real time, adding a supplementary carbon source, and running for a period of time. After the total nitrogen removal rate is stable, only urban domestic sewage is used as a carbon source, and biochar-loaded nano zero-valent iron material is added; S2 operation stage: add urban domestic sewage and nitrate wastewater into the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3), and add an external carbon source; then perform anoxic stirring without aeration; finally perform sedimentation and drainage, the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) does not actively discharge sludge, and the supernatant after sedimentation is discharged.

2. The method according to claim 1, characterized in that In step S1, the mixed sludge includes anaerobic ammonium oxidation granular sludge and short-cut denitrification sludge; The volume ratio of the anaerobic ammonium 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-loaded nano zero-valent iron material is 800-2000 mg / L; the mass ratio of carbon to iron in the biochar-loaded 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; The temperature in the short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) is 24°C to 26°C, the pH is 7.2 to 7.4, and the dissolved oxygen is 0 to 0.2 mg / L.

6. The method according to claim 1, characterized in that In step S1, the total nitrogen removal rate is stabilized, which means >80%, and the C / N value is 2-3; and 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-range denitrification coupled anaerobic ammonium 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 by means of the water quality online detector (5); the sedimentation and drainage time is 10 to 30 minutes; and the drainage ratio is 40 to 60%.

9. The method according to claim 1, characterized in that: The denitrification and phosphorus removal device for enhancing the efficiency of short-range denitrification coupled anaerobic ammonium oxidation reaction comprises a nitrate wastewater storage tank (1), a domestic sewage storage tank (2), a short-range denitrification coupled anaerobic ammonium oxidation denitrification 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 water inlet (3.1) of the short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) through a first peristaltic pump (1.1); the domestic sewage storage tank (2) is connected to the second water inlet (3.2) of the short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) through a second peristaltic pump (2.1); the external carbon source storage tank (4) is connected to the third water inlet (3.3) of the short-range denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) through a third peristaltic pump (4.1), and the outlet water is discharged through an outlet valve (3.5); The short-cut denitrification coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3) is provided with a first water inlet (3.1), a second water inlet (3.2), a third water 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), an agitator (7) and an exhaust port (8); The online detection system comprises a water quality measuring instrument (5) and an online parameter measuring instrument host (6); the water quality measuring instrument (5) is connected to the online parameter measuring instrument host (6); The automatic control system comprises 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 meter (5) and the online parameter meter host (6) to form an online detection system; Biochar-loaded nano zero-valent iron material is placed in the short-range denitrification-coupled anaerobic ammonium oxidation denitrification and phosphorus removal reactor (3).

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