Method for efficiently treating nitrogen-containing wastewater by using iron accelerant

Abstract

The invention discloses a method for efficiently treating nitrogen-containing wastewater by using an iron accelerant. The method comprises the following steps: S1, inoculating seed sludge with high anaerobic ammonia oxidation activity into a reactor of an anaerobic ammonia oxidation system; s2, nanoscale hematite is added into the reactor at a time to serve as an iron accelerant; s3, controlling the operation conditions of the reactor; s4, running in a continuous flow form, controlling the ammonia nitrogen concentration of inlet water to be 300-400 mg / L, and controlling the nitrite nitrogen / ammonia nitrogen concentration ratio of the inlet water to be 1.1 + / -0.1; s5, trace elements, calcium ions and phosphorus ions are supplemented according to the water quality characteristics of the inlet water, so that the sludge particle density of the anaerobic ammonium oxidation bacteria is improved, and the growth speed and activity of the anaerobic ammonium oxidation bacteria are further improved. The nanoscale hematite is fully contacted and mixed with the anaerobic ammonium oxidation flora to serve as a conductive material, so that extracellular electron transfer of microorganisms can be enhanced, starting of anaerobic ammonium oxidation reaction is accelerated, and relative abundance of anaerobic ammonium oxidation bacteria in the microbial community is improved.

Description

Technical Field

[0001] The invention belongs to the field of nitrogen-containing wastewater treatment, and more specifically, particularly relates to a method for efficiently treating nitrogen-containing wastewater by utilizing an iron promoter. Background Art

[0002] Ammonia nitrogen is one of the main indicators of water pollution in my country and one of the main targets for pollution source reduction. With the rapid development of petrochemical, pharmaceutical and agricultural and sideline food industries, the nitrogen concentration in wastewater has gradually increased. The traditional biological denitrification process has high requirements for organic matter and is difficult to meet the denitrification requirements of low C / N (COD / ammonia nitrogen) wastewater. Short-range nitrification-anaerobic ammonia oxidation effectively makes up for the defects of traditional biological denitrification processes. It has many advantages such as low oxygen demand, no need to add additional carbon source, low sludge production, and saving aeration. It has broad application prospects. However, the stability of the anaerobic ammonia oxidation process is relatively strict. It is necessary to ensure that there is enough oxygen in the reactor to convert enough ammonia nitrogen into nitrite, and it is necessary to avoid excessive oxygen supply, which will cause nitrite oxidizing bacteria to oxidize nitrite and inhibit anaerobic ammonia oxidizing bacteria. At the same time, because anaerobic ammonia oxidizing bacteria are more sensitive to the environment, they are also easily lost in the process system, resulting in low denitrification efficiency of the anaerobic ammonia oxidation system and poor bacterial retention capacity in the system.

[0003] Iron is one of the important trace elements for microorganisms. Adequate iron ion concentration in the reactor can promote the transfer of energy in microorganisms and play a key role in the metabolism and growth of microorganisms. Iron can also affect the metabolism of anaerobic ammonium oxidizing bacteria. When divalent iron and trivalent iron are added to the anaerobic ammonium oxidation system, the interaction between iron ions and negatively charged extracellular polymers can improve the density of anaerobic ammonium oxidizing bacteria biomass particles and protect cells from external pressure, thereby effectively improving the biomass retention capacity in the reactor; at the same time, the addition of trivalent iron ions can promote the growth rate of anaerobic ammonium oxidizing bacteria. When the concentration of trivalent iron ions gradually increases within a suitable range, the growth rate of anaerobic ammonium oxidizing bacteria shows a gradually increasing trend. The addition of trivalent iron can improve the activity of anaerobic ammonium oxidizing sludge and enhance the sludge's tolerance to organic matter. The relative abundance of anaerobic ammonium oxidizing bacteria in the anaerobic ammonium oxidation reactor is positively correlated with the concentration of trivalent iron added. The addition of trivalent iron can promote the enrichment and growth of anaerobic ammonium oxidizing bacteria.

[0004] In the prior art, anaerobic ammonium oxidizing bacteria grow slowly, have a long doubling time, have few highly active inocula, and are difficult to enrich and culture, resulting in a slow start-up of the anaerobic ammonium oxidizing process. Adding admixtures to the anaerobic ammonium oxidizing process system is an effective method to stabilize the process, enhance sludge activity, and promote bacterial enrichment. Hydrazine and iron ions are two commonly used admixtures, but the addition of hydrazine admixtures has a high operating cost, and in the anaerobic ammonium oxidizing process, if a good operating state is to be maintained, hydrazine needs to be continuously added to the reaction system, resulting in a certain dependence of anaerobic ammonium oxidizing bacteria on hydrazine. The addition of iron ions to the anaerobic ammonium oxidizing system is generally done by setting a dosing box in the water inlet tank. The iron ions will gradually be lost during the process of water inlet and outlet, and it is difficult to be recycled. The continuous addition of iron ions causes a waste of resources, poor denitrification efficiency, and excessive iron adsorption and precipitation by the sludge in the system, and the cost of addition is also high.

[0005] In order to further illustrate the problems existing in the above-mentioned prior art, the patent CN 117923655 A proposes a method for improving the denitrification performance of the anaerobic ammonium oxidation system in treating sewage, which includes the following steps: inoculating anaerobic ammonium oxidation granular sludge into the bottom of the reactor of the anaerobic ammonium oxidation system, adding hydrophilic polystyrene microspheres to the surface of the anaerobic ammonium oxidation granular sludge, and adding trace element I preparation liquid and trace element II preparation liquid to the influent; the trace element I preparation liquid includes the following components: ferrous sulfate heptahydrate, ferrous titanate, disodium ethylenediaminetetraacetic acid; the trace element II preparation liquid includes the following components: cobalt chloride hexahydrate, nickel chloride hexahydrate, sodium molybdate dihydrate, zinc chloride, manganese chloride tetrahydrate. Through the above-mentioned technical scheme, the problem of low removal rate of ammonia nitrogen and nitrite nitrogen in the anaerobic ammonium oxidation system in the prior art is solved;

[0006] Another example is the patent CN 117945551 A, which provides a device and method for promoting biological treatment of high-ammonia nitrogen wastewater by strengthening iron reduction using MEC, belonging to the field of water treatment and environmental protection purification treatment technology. The invention first adds iron hydroxide to the anaerobic ammonium oxidation granular sludge to induce Fe (III) reduction coupling anaerobic ammonium oxidation denitrification; then the resulting sludge is added to the anaerobic MEC reactor to strengthen Fe (III) reduction coupling anaerobic ammonium oxidation denitrification; during the operation of the anaerobic MEC reactor, iron hydroxide is added every 40 to 70 days to supplement the aged Fe (III). The invention participates in the treatment of high ammonia nitrogen in wastewater by adding Fe (III) as an alternative electron acceptor, and uses MEC to strengthen the extracellular electron transfer process of anaerobic ammonium oxidizing bacteria, thereby improving the denitrification efficiency. The device and method can efficiently treat wastewater with a ratio of influent ammonia nitrogen to nitrite nitrogen between 1.0 and 1.5. Compared with anaerobic ammonium oxidation reactors that need to be coupled with technologies such as short-range nitrification, it can save construction costs and energy consumption to a large extent, and has broad application prospects.

[0007] In summary, we proposed a method for efficiently treating nitrogen-containing wastewater using iron promoters, focusing on controlling the operating environment of the anaerobic ammonium oxidation system. By adding nano-scale hematite inside the reactor, the nano-scale hematite is fully mixed with microorganisms. Under the conditions of reducing costs and improving the utilization rate of hematite, the growth rate of anaerobic ammonium oxidizing bacteria, the specific anaerobic ammonium oxidation activity of anaerobic ammonium oxidizing sludge and the relative abundance of anaerobic ammonium oxidizing bacteria, and the biomass retention capacity in the reactor are effectively increased. Summary of the invention

[0008] The purpose of the present invention is to solve the shortcomings of the prior art and propose a method for efficiently treating nitrogen-containing wastewater using an iron promoter. Nano-scale hematite is fully contacted and mixed with the anaerobic ammonium-oxidizing bacteria community. As a conductive material, it can enhance the extracellular electron transfer of microorganisms, accelerate the start-up of the anaerobic ammonium-oxidizing reaction, and increase the relative abundance of anaerobic ammonium-oxidizing bacteria in the microbial community.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A method for efficiently treating nitrogen-containing wastewater using an iron promoter comprises the following steps:

[0011] S1. Inoculating seed mud with high anaerobic ammonium oxidation activity into the reactor of the anaerobic ammonium oxidation system;

[0012] S2, adding nano-scale hematite as an iron promoter into the reactor at one time;

[0013] S3, controlling the operating conditions of the reactor;

[0014] S4, continuous flow operation, the inlet ammonia nitrogen concentration is controlled at 300-400 mg / L, and the inlet nitrite nitrogen / ammonia nitrogen concentration ratio is controlled at 1.1±0.1;

[0015] S5. Supplement trace elements and calcium and phosphorus ions according to the characteristics of the influent water quality to increase the sludge particle density of anaerobic ammonium oxidizing bacteria, thereby increasing the growth rate and activity of anaerobic ammonium oxidizing bacteria.

[0016] Preferably, in step S1, the reactor is inoculated with anaerobic ammonia oxidation seed mud with a high abundance, and the inoculation amount is 25%.

[0017] Preferably, the anaerobic ammonium oxidation system supplements trace elements according to the influent water quality characteristics, wherein the trace elements are added in the form of a concentrated solution, and the formula of the concentrated solution is (g / L): H3BO4 0.014, MnCl2·4H2O 0.99, ZnSO4·7H2O 0.43, (NH4)6Mo7O 24·4H2O 0.177, CoCl2·6H2O 0.24, CuSO4·5H2O 0.25, NiCl2·6H2O 0.199, dosage is 1 mL / L.

[0018] Preferably, the anaerobic ammonium oxidation system supplements calcium and phosphorus ions according to the influent water quality characteristics, and the concentrations of calcium and phosphorus ions are controlled at 40 mg / L and 10 mg / L, respectively.

[0019] Preferably, the continuous flow operation in step S4 is achieved by a timed water inlet and outlet system to maintain a constant hydraulic retention time in the reactor.

[0020] Preferably, the reactor is built with a high-efficiency biological filler to form biofilm, thereby achieving the enrichment of anaerobic ammonia-oxidizing bacteria.

[0021] Preferably, in step S3, the operating conditions of the reactor include maintaining the temperature at 30-35°C, controlling the pH value between 7.5 and 8.3, and maintaining the dissolved oxygen concentration below 0.5 mg / L.

[0022] Preferably, the concentration of nano-hematite added in the anaerobic ammonium oxidation stage is in the range of 0.1-2.0 g / L to promote the growth and activity of anaerobic ammonium oxidizing bacteria.

[0023] Preferably, after the treatment cycle is completed, the sludge in the reactor is settled and separated to recover and reuse the microbial flora therein, thereby reducing the cost and environmental impact of sludge treatment.

[0024] The technical effects and advantages of the present invention are as follows: the present invention provides a method for efficiently treating nitrogen-containing wastewater using an iron promoter. Compared with the conventional technology, the present invention can shorten the start-up time of anaerobic ammonia-oxidizing bacteria by adding an external nano-hematite promoter, and realize the rapid expansion of bacterial strains. At the same time, the present invention adds nano-hematite in the reactor to synergistically treat nitrogen-containing wastewater, which can effectively increase the growth rate of anaerobic ammonia-oxidizing bacteria, increase the activity of anaerobic ammonia-oxidizing sludge and the relative abundance of anaerobic ammonia-oxidizing bacteria in the reactor, and increase the biomass retention capacity in the reactor;

[0025] Nano-scale hematite is fully contacted and mixed with the anaerobic ammonium-oxidizing bacteria. As a conductive material, it can enhance the extracellular electron transfer of microorganisms, accelerate the start-up of the anaerobic ammonium-oxidizing reaction, and increase the relative abundance of anaerobic ammonium-oxidizing bacteria in the microbial community.

[0026] Adding nano-scale hematite as condensation nuclei promotes the formation of anaerobic ammonium oxidation granular sludge, reduces microbial loss, and improves the stability of the anaerobic ammonium oxidation system;

[0027] Nano-scale hematite only needs to be added once, and long-term stable operation reduces operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a data diagram of the content of each component in the effluent of the nitrogen-containing wastewater after treatment in the reactor without adding nano-scale hematite in Example 1 of the present invention;

[0029] Figure 2 This is a data graph showing the effect of nano-hematite on the start-up time of anaerobic ammonia-oxidizing bacteria in Example 2 of the present invention;

[0030] Figure 3 This is a data graph showing the change in the specific anaerobic ammonium oxidation activity of anaerobic ammonium oxidizing bacteria over time in Example 3 of the present invention;

[0031] Figure 4 This is a data diagram of the relative abundance of Planctomyces at the phylum level in two reactors in Example 4 of the present invention;

[0032] Figure 5 This is a data diagram of the relative abundance of the dominant species of anaerobic ammonia-oxidizing bacteria in the microbial community at the genus level in the two reactors in Example 4 of the present invention;

[0033] Figure 6 This is a diagram of the method for efficiently treating nitrogen-containing wastewater using an iron promoter according to the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] The present invention provides a method for efficiently treating nitrogen-containing wastewater using an iron promoter, comprising the following steps:

[0036] A method for efficiently treating nitrogen-containing wastewater using an iron promoter, such as Figure 6 , including the following steps:

[0037] S1. Inoculate the reactor of the anaerobic ammonium oxidation system with seed mud having high anaerobic ammonium oxidation activity; in step S1, inoculate the reactor with seed mud having high anaerobic ammonium oxidation abundance, with an inoculation amount of 25%.

[0038] S2, adding nano-scale hematite as an iron promoter into the reactor at one time;

[0039] S3, controlling the operating conditions of the reactor;

[0040] S4, continuous flow operation, the inlet ammonia nitrogen concentration is controlled at 300-400 mg / L, and the inlet nitrite nitrogen / ammonia nitrogen concentration ratio is controlled at 1.1±0.1;

[0041] S5. Supplement trace elements and calcium and phosphorus ions according to the characteristics of the influent water quality to increase the sludge particle density of anaerobic ammonium oxidizing bacteria, thereby increasing the growth rate and activity of anaerobic ammonium oxidizing bacteria.

[0042] As mentioned above, anaerobic ammonium oxidation supplements trace elements according to the characteristics of the influent water quality, where the trace elements are added in the form of concentrated solution, and the formula of the concentrated solution is (g / L): H3BO4 0.014, MnCl2·4H2O 0.99, ZnSO4·7H2O 0.43, (NH4)6Mo7O 24 ·4H2O 0.177, CoCl2·6H2O 0.24, CuSO4·5H2O 0.25, NiCl2·6H2O 0.199, dosage is 1 mL / L.

[0043] Furthermore, the present invention uses an anaerobic ammonium oxidation process to treat nitrogen-containing wastewater. In the embodiment, the anaerobic ammonium oxidation system consists of a plexiglass reactor (total volume of 2.5L, effective volume of 2L), a high-efficiency biological carrier and a dosing box. Two groups of experiments are set up, namely AMXⅠ and AMXⅡ, wherein AMXⅠ is a reactor without adding nano-scale hematite, and AMXⅡ is a reactor with a one-time addition of (0.1-2.0) g / L hematite. Both reactors are inoculated with anaerobic ammonium oxidation seed mud with a high abundance, the inoculation amount is 25%, the temperature is controlled at 30±0.5 ℃, and it is operated in a continuous flow form, with built-in high-efficiency biological filler biofilm to achieve the enrichment of anaerobic ammonium oxidizing bacteria;

[0044] The influent ammonia nitrogen concentration is controlled at 300-400 mg / L, and the influent nitrite nitrogen / ammonia nitrogen concentration ratio is controlled at 1.1±0.1; anaerobic ammonia oxidation supplements trace elements according to the influent water quality characteristics, where trace elements are added in the form of concentrated solution, and the formula of the concentrated solution is (g / L): H3BO4 0.014, MnCl2·4H2O 0.99, ZnSO4·7H2O 0.43, (NH4)6Mo7O 24 ·4H2O 0.177, CoCl2·6H2O 0.24, CuSO4·5H2O 0.25. NiCl2·6H2O 0.199, dosage is 1 mL / L.

[0045] The anaerobic ammonium oxidation system supplements calcium and phosphorus ions according to the characteristics of the influent water quality, and the concentrations of calcium and phosphorus ions are controlled at 40 mg / L and 10 mg / L respectively.

[0046] The operation control factors of this system mainly include the following aspects:

[0047] ①Temperature: The temperature is controlled between 30 and 35°C;

[0048] ②pH: pH value should be controlled between 7.5 and 8.3;

[0049] ③Dissolved oxygen: The dissolved oxygen concentration is controlled below 0.5 mg / L.

[0050] The above method can accelerate the start-up of the anaerobic ammonium oxidation reaction, promote the formation of anaerobic ammonium oxidation granular sludge, increase the activity of anaerobic ammonium oxidation sludge and the relative abundance of anaerobic ammonium oxidation bacteria in the reactor, increase the biomass retention capacity in the reactor, and improve the stability of the anaerobic ammonium oxidation system during operation by adding nano-sized hematite to the anaerobic ammonium oxidation system, which is fully mixed with the anaerobic ammonium oxidation bacteria and operated in combination with a high-efficiency biological carrier.

[0051] Example 1

[0052] like Figure 1 As shown, AMXⅠ maintains the inlet ammonia nitrogen concentration at (300-400) mg / L, the inlet nitrite nitrogen at (340-440) mg / L, and the inlet nitrite nitrogen / ammonia nitrogen concentration ratio is stable at about 1.2. The system does not add nano-hematite. The removal rate of total nitrogen in the reactor effluent is 84.8-99.0%, the pH value in the reactor is stable between 7.5 and 8.3, and the dissolved oxygen is stable below 0.2 mg / L. The denitrification load of AMXⅠ increased to 1.4 g / L·d within 70 days of operation, while the denitrification load of AMXⅡ showed a steady growth trend within 23 days (see Figure 2 ), which not only shortens the start-up time of anaerobic ammonia-oxidizing bacteria, but also effectively promotes the rapid expansion of bacterial strains.

[0053] Example 2

[0054] like Figure 2 As shown in the figure, the AMXⅡ system maintains the inlet ammonia nitrogen concentration at (300-400) mg / L, the inlet nitrite nitrogen at (340-440) mg / L, and the inlet nitrite nitrogen / ammonia nitrogen concentration ratio is stable at about 1.2. The system adds 1g / L of nano-hematite in the reactor, and the total nitrogen removal rate ranges from 83.2 to 96.7%; the pH value in the reactor is stable between 7.5 and 8.0, the dissolved oxygen is stable below 0.2 mg / L, and the denitrification load steadily increases to 1.6 g / L·d within 23 days of operation ( Figure 2 ), and then it has been in a relatively stable growth trend, while AMXⅠ needs to run for 70 days before the denitrification load can steadily increase to more than 1.4 g / L·d ( Figure 1 );

[0055] Example 3

[0056] like Figure 3 The activity of anaerobic ammonium oxidizing bacteria in the two groups of reactors was measured. On the 23rd day of operation of the AMXⅡ reactor, the specific anaerobic ammonium oxidation activity (SAA) of the anaerobic ammonium oxidizing sludge increased from 0.16 gN·g-VSS to -1 ·d -1 Increased to 0.27 gN·g-VSS -1 ·d -1 On the 70th day, SAA increased to 0.32 gN·g-VSS -1 ·d -1 After 23 days of operation, the SAA of the AMXⅠ reactor increased from 0.16 gN·g-VSS to -1 ·d -1 Increased to 0.19 gN·g-VSS -1 ·d -1 , SAA increased to 0.23gN·g-VSS on the 70th day of operation -1 ·d -1 ,The data showed that by adding nano-scale hematite in the reactor, the start-up time of anaerobic ammonium-oxidizing bacteria can be shortened and the activity of anaerobic ammonium-oxidizing sludge can be effectively improved.

[0057] Example 4

[0058] like Figure 4 and Figure 5 After the reactors had been running for 70 days, appropriate amounts of mud-water mixture were taken from the AMXⅠ and AMXⅡ reactors for bacterial diversity analysis. The microbial community structure of anaerobic ammonia-oxidizing bacteria in the two reactors was determined based on 16S rRNA sequencing analysis. The dominant genus of anaerobic ammonia-oxidizing bacteria in the two groups of reactors was mainly Ca. Brocadia.

[0059] According to the results of diversity analysis, the phylum-level distribution diagrams of the microbial communities in the two reactors were drawn as follows: Figure 4 As shown, in AMXⅠ, the relative abundance of the phylum Planctomyces, where the anaerobic ammonium oxidizers are located, is 1.54% at the phylum level, while in AMXⅡ, the relative abundance of the phylum Planctomyces, where the anaerobic ammonium oxidizers are located, is 6.20% at the phylum level.

[0060] According to the results of diversity analysis, the genus-level distribution diagram of the microbial communities in the two reactors was drawn as follows: Figure 5 As shown, for AMXⅠ, the relative abundance of Ca.Brocadia in the microbial community at the genus level was 1.16%, and in AMXⅡ, the relative abundance of Ca.Brocadia in the microbial community at the genus level was 5.62%.

[0061] The data showed that by adding nano-sized hematite into the reactor, the relative abundance of anaerobic ammonia-oxidizing bacteria in the reactor could be effectively increased.

[0062] In summary: the present invention adds nanometer-sized hematite to the anaerobic ammonium oxidation system, and by fully mixing it with the anaerobic ammonium oxidizing bacteria and operating it together with a high-efficiency biological carrier, the start-up of the anaerobic ammonium oxidation reaction can be accelerated, the formation of anaerobic ammonium oxidation granular sludge can be promoted, the activity of the anaerobic ammonium oxidation sludge and the relative abundance of anaerobic ammonium oxidizing bacteria in the reactor can be increased, the biomass retention capacity in the reactor can be increased, and the stability of the anaerobic ammonium oxidation system can be improved during operation.

[0063] Based on the above, the present invention can intuitively derive the following effects:

[0064] 1. Anaerobic ammonium oxidizing bacteria are difficult to enrich and culture, have a long doubling time and a long start-up time. By adding nano-scale hematite, the start-up time of anaerobic ammonium oxidizing bacteria can be shortened and the rapid expansion of the strain can be achieved.

[0065] 2. The present invention adds nano-scale hematite in the reactor to synergistically treat nitrogen-containing wastewater with microbial flora, which can effectively increase the growth rate of anaerobic ammonia-oxidizing bacteria, increase the activity of anaerobic ammonia-oxidizing sludge and the relative abundance of anaerobic ammonia-oxidizing bacteria in the reactor, and improve the biomass retention capacity in the reactor.

[0066] 3. Compared with the method of continuously adding iron ions and hydrazine and other additives to the influent, nano-hematite can be fully mixed with microorganisms and retained in the reactor. While greatly reducing the cost of reagents, it allows the anaerobic ammonia-oxidizing bacteria to enrich and grow in a stable environment, and has good application prospects.

[0067] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for efficiently treating nitrogen-containing wastewater using an iron accelerator, characterized in that: The steps include: S1. Inoculating seed mud with high anaerobic ammonium oxidation activity into the reactor of the anaerobic ammonium oxidation system; S2, adding nano-scale hematite as an iron promoter into the reactor at one time; S3, controlling the operating conditions of the reactor; S4, continuous flow operation, the inlet ammonia nitrogen concentration is controlled at 300-400 mg / L, and the inlet nitrite nitrogen / ammonia nitrogen concentration ratio is controlled at 1.1±0.1; S5. Supplement trace elements and calcium and phosphorus ions according to the characteristics of the influent water quality to increase the sludge particle density of anaerobic ammonium oxidizing bacteria, thereby increasing the growth rate and activity of anaerobic ammonium oxidizing bacteria.

2. A method for efficiently treating nitrogen-containing wastewater using an iron accelerator according to claim 1, characterized in that: The reactor was inoculated with anaerobic ammonium oxidation sludge with a high abundance, with an inoculation amount of 25%.

3. A method for efficiently treating nitrogen-containing wastewater using an iron accelerator according to claim 1, characterized in that: Anaerobic ammonium oxidation supplements trace elements according to the characteristics of the influent water quality. The trace elements are added in the form of concentrated solution. The formula of the concentrated solution is (g / L): H3BO4 0.014, MnCl2·4H2O 0.99, ZnSO4·7H2O 0.43, (NH4)6Mo7O 24 ·4H2O0.177, CoCl2·6H2O 0.24, CuSO4·5H2O 0.25, NiCl2·6H2O 0.199, dosage is 1 mL / L.

4. A method for efficiently treating nitrogen-containing wastewater using an iron accelerator according to claim 1, characterized in that: The anaerobic ammonium oxidation system supplements calcium and phosphorus ions according to the influent water quality characteristics, and the concentrations of calcium and phosphorus ions are controlled at 40 mg / L and 10 mg / L, respectively.

5. The method for efficiently treating nitrogen-containing wastewater using an iron accelerator according to claim 1, characterized in that: The continuous flow operation in step S4 is achieved by a timed water inlet and outlet system to maintain a constant hydraulic retention time in the reactor.

6. A method for efficiently treating nitrogen-containing wastewater using an iron accelerator according to claim 1, characterized in that: The reactor is built with high-efficiency biological filler to form biofilm, so as to achieve the enrichment of anaerobic ammonia-oxidizing bacteria.

7. A method for efficiently treating nitrogen-containing wastewater using an iron accelerator according to claim 6, characterized in that: In step S3, the operating conditions of the reactor include maintaining the temperature at 30-35°C, controlling the pH value between 7.5 and 8.3, and maintaining the dissolved oxygen concentration below 0.5 mg / L.

8. A method for efficiently treating nitrogen-containing wastewater using an iron accelerator according to claim 7, characterized in that: The concentration of nano-hematite added in the anaerobic ammonium oxidation stage is in the range of 0.1-2.0 g / L to promote the growth and activity of anaerobic ammonium oxidizing bacteria.

9. A method for efficiently treating nitrogen-containing wastewater using an iron accelerator according to claim 1, characterized in that: After the treatment cycle is completed, the sludge in the reactor is settled and separated to recover and reuse the microbial flora therein, reducing the cost and environmental impact of sludge treatment.

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