CN105271514A - Biological nitrogen removal method based on anaerobic Feammox and application thereof - Google Patents

Abstract

The invention discloses a biological denitrification method based on anaerobic iron oxidation of ammonia, comprising the following steps: adding sludge containing Feammox microorganisms to an anaerobic reactor, passing ammonia-containing sewage into the reactor, and using Fe(III ) NTA oxidizes NH ₄ ⁺ in sewage to generate NO ₂ ^- , and then performs denitrification treatment. The specific steps are: 1. Cultivate and enrich Feammox microorganisms: 1) Sludge pretreatment, 2) Feammox microorganism cultivation; 2. Use Feammox Microbial treatment of NH ₄ ⁺ in sewage: 1) sewage pretreatment, 2) sewage treatment using Feammox microorganisms; 3, denitrification of the liquid collected after the aforementioned anaerobic Feammox treatment. The method has the advantages of lower energy consumption, less demand for carbon sources, less greenhouse gas emissions, less NO ₃ ^- generation, low investment and operating costs, and broad application prospects.

Description

Biological denitrification method based on anaerobic iron oxidation of ammonia and its application

technical field

The invention belongs to the technical field of sewage treatment, and in particular relates to a method for treating ammonia in sewage by using anaerobic iron to oxidize ammonia and its application in sewage denitrification.

Background technique

At present, the microbial processes that can realize NH ₄ ⁺ oxidation in sewage treatment are mainly aerobic ammonium oxidation and anaerobic ammonium oxidation. Although the traditional aerobic ammonium oxidation process has been widely used in sewage treatment, this process needs oxygen from the outside to be able to experiment with the oxidation of NH ₄ ⁺ . At the same time, there are oxygen and product NO ₂ ^- in the aerobic ammonium oxidation system. Therefore, there are usually nitrite oxidizing bacteria in the system to oxidize NO ₂ ^- to NO ₃ ^- , and then after the denitrification process, NO ₃ ^- can be reduced to N ₂ to achieve the removal of NH ₄ ⁺ , so the traditional nitrification and denitrification The process needs to add O ₂ and organic matter, and at the same time, the sludge output is high. Although the anaerobic ammonium oxidation process can oxidize NH ₄ ⁺ under anaerobic conditions, it needs to provide NO ₂ ^- to realize the oxidation of NH ₄ ⁺ , so this process needs to be combined with the aerobic ammonium oxidation process to realize NH ₄ ⁺ Oxidation.

Iron is a type of transition metal, which is the second most abundant metallic element in the earth's crust. Redox reactions of Fe with C, O, N, and S drive global biochemical cycles. Fe(Ⅲ) reduction by microbial dissimilation is an important biological and geochemical process, which not only affects the distribution and mineralogy of iron, but also has been gradually applied because the reduction process of microbial dissimilation Fe(Ⅲ) is coupled with the oxidative degradation of organic matter. It is used in biometallurgy, bioremediation of heavy metal (uranium, chromium, arsenic, etc.) polluted environment and biodegradation of petrochemical organic sewage. Fe also plays a role in the chemical and microbial redox processes of N-containing species, including the production of the greenhouse gas _N2O . There are a wide variety of microorganisms that can reduce Fe(III) iron in nature, ranging from archaea to bacteria. However, the biochemical properties of microbial Fe(III) reduction are still a relatively new field of research.

Current studies have found that in rice fields, sediments, freshwater ecosystems and other environments, the phenomenon of relying on Fe(III) to oxidize NH4+ under anaerobic conditions is ubiquitous. This phenomenon is called Feammox (iron oxidation ammonia).文献如：1)河流沉积物中：Clement等(Ammoniumoxidationcoupledtodissimilatoryreductionofironunderanaerobicconditionsinwetlandsoils，2005)；2)湿地生态系统：Shrestha等.(OxidationofAmmoniumtoNitriteUnderIron-ReducingConditionsinWetlandSoilsLaboratory,FieldDemonstrations,andPush-PullRateDetermination，2009)；3)山地土壤：Yang等(Nitrogenlossfromsoilthroughanaerobicammoniumoxidationcoupledtoironreduction ,2012)；4)河岸草地：HuangandJaffe等(Characterizationofincubationexperimentsanddevelopmentofanenrichmentculturecapableofammoniumoxidationunderiron-reducingconditions，2015)；5)厌氧消化污泥：Sawayama等(Possibilityofanoxicferricammoniumoxidation.JournalofBioscienceandBioengineering，2006)；6)稻田土壤：Ding等.(NitrogenLossthroughAnaerobicAmmoniumOxidationCoupledtoIronReductionfromPaddySoilsinaChronosequence,2014) ; 7) Freshwater lake sediment: Melton et al (Microbialiron (II) oxidation in littoral fresh water lake sediment: the potential for competition between phototrophic vs. rs, 2012). Existing studies believe that the Feammox reaction principle is as follows

Jaffé of Princeton University in the United States found Feammox bacteria in the soil of riverbank grasslands, which can realize Feammox. They took soil samples from the site and used anaerobic reactors in the laboratory to pass ferrihydrite or goethite through 180 days. Feammox bacteria were cultured, but because of the low solubility and poor bioavailability of iron in ferrihydrite or goethite, the enrichment effect is not very ideal.

Feammox microorganisms can oxidize NH ₄ ⁺ to NO ₂ ^- under anaerobic conditions. Combining this process with the anaerobic ammonium oxidation (Anammox) process in sewage treatment systems, it is possible to achieve NH ₄ ⁺ under anaerobic conditions. Compared with the traditional nitrification-denitrification process, this coupled process will have lower energy consumption, less carbon source demand, less greenhouse gas emissions (such as N ₂ O ₎ , less The advantages of NO ₃ ^-production and lower sludge production. Therefore, this reaction has broad application prospects in sewage treatment.

Although the content of iron in the surface environment and sediments is very high, the solubility of Fe(Ⅲ) is only 10 ^-9 mol under neutral conditions. In most cases, Fe(Ⅲ) in the aquifer is insoluble in the form of iron oxides. This limits the abundance of Fe-ammox microorganisms, so by increasing the content of bioavailable Fe(III), the Fe-ammox process can be effectively promoted, for example, by adding NTA (nitrilotriacetic acid), EDTA (ethylenediamine Soluble chelated iron is formed under the action of chelating agents such as tetraacetic acid) and polyphosphate, and is transported to the surface of microorganisms by diffusion, thereby enhancing the Feammox process.

Contents of the invention

The purpose of the present invention is to provide a biological denitrification method based on anaerobic iron ammonia oxidation with low energy consumption, low investment and operating costs and broad application prospects.

The technical scheme of the present invention is as follows: a kind of biological denitrification method based on anaerobic ferric ammonium oxidation comprises the following steps: adding the sludge containing Feammox microorganism in the anaerobic reactor, passing ammonia-containing sewage into the reactor, utilizing Fe(III)NTA oxidizes NH ₄ ⁺ in sewage to generate NO ₂ ^- , and then performs denitrification treatment. The specific steps are as follows:

1. Cultivate and enrich Feammox microorganisms

1) Sludge pretreatment: mix the provenance sludge containing Feammox microorganisms with a culture solution to obtain a mud-water mixture, and the culture solution is obtained by mixing a nutrient solution and a trace element solution, and the composition ratio is as follows: Add 1.0-1.5mL trace element solution; the nutrient solution contains 0.16-0.20mM Fe(III)NTA, 2.00-2.30mM NH ₄ ⁺ and minerals;

2) Cultivation of Feammox microorganisms: Connect the aforementioned mud-water mixture into an anaerobic reactor, first expose to _N2 until the dissolved oxygen in the mud-water mixture is 0mg/L, then start the reactor, add half the volume of the mud-water mixture for the aforementioned cultivation The solution runs for 180-240 minutes, then stops running for 15-25 minutes, and discharges the supernatant after precipitation. The discharge volume is the same as the volume of the added culture solution. At this point, a treatment cycle is completed; Culture liquid, start a new treatment cycle, and complete multiple operation cycles in this way; the operating temperature of the reactor is 30-35°C, and the pH of the mud-water mixture in the reactor is controlled at 7.0-8.0; the reaction is discharged from the reactor once a day One-fifteenth of the total volume of the final mud-water mixture is discarded, and then refilled with a new culture solution of the same volume as the discarded solution; a total of 70 to 110 days of operation;

2. Using Feammox microorganisms to treat NH ₄ ⁺ in sewage

1) Sewage pretreatment: Add 0.16-0.20mMFe(III)NTA to the ammonia-containing sewage to be treated, dissolve and mix the minerals to obtain a mixed solution, and then add trace elements at a rate of 1.0-1.5mL of trace element solution per liter of the mixed solution The element solution is mixed to obtain the sewage pretreatment liquid;

2) Drain half of the volume of the mud-water mixture obtained after enriching and cultivating Feammox microorganisms, and then add it to the anaerobic reactor for sewage treatment: add the same volume of the mud-water mixture in the reactor as the aforementioned sewage pretreatment The solution runs for 180-240 minutes, then stops to settle for 15-25 minutes, discharges the solution with the same volume as the sewage pretreatment solution added after the precipitation and collects the liquid, and completes a treatment cycle; Volume of sewage pretreatment liquid, start a new treatment cycle, so that the sewage treatment can be carried out continuously; the operating temperature of the reactor is 30-35 ℃, and the pH of the mud-water mixture in the reactor is controlled at 7.0-8.0; once a day Discard one-fifteenth of the total volume of the reacted mud-water mixture from the reactor, and then replenish the same volume of sewage pretreatment liquid as the effluent; so far, the conversion of NH ₄ ⁺ in sewage into NO ₂ ^- the process of;

3. The liquid collected after the aforementioned anaerobic Feammox treatment is subjected to denitrification treatment.

Preferably, the concentration of Fe(III)NTA in the nutrient solution is 0.18mM, the concentration of NH ₄ ⁺ is 2.15mM, and the concentration of Fe(III)NTA in the sewage pretreatment solution is 0.18mM.

Preferably, the Fe(III)NTA is prepared from Fe ₂ (SO ₄ ) ₃ and NTA at a molar ratio of 1:1, and the NH ₄ ⁺ is derived from ammonium sulfate or ammonium chloride.

In the above technical solution, the mineral components and ratios contained in the nutrient solution and the sewage pretreatment solution are: NaH ₂ PO ₄ 0.04～0.06g/L, CaCl ₂ ·2H ₂ O0.2～ 0.4g/L, MgSO ₄ ·7H ₂ O 0.2～0.4g/L, KHCO ₃ 1.0～1.5g/L, FeSO ₄ 0.0060～0.0065g/L, EDTA0.0060～0.0065g/L; The element solution includes components with the following concentrations: _EDTA13 ～17g/L, _H3BO40.010 ～0.016g/L, MnCl2 _{· 4H2O0.90} ～1.10g/L, CuSO4 _{· 5H2O0.20} ～0.30 g/L, ZnSO ₄ ·7H ₂ O 0.35～0.50g/L, NiCl ₂ ·6H ₂ O0.15～.025g/L, Na ₂ SeO ₄ ·10H ₂ O0.15～0.26g/L, Na ₂ MoO ₄ ·2H ₂ O 0.17-0.27g/L, Na ₂ WO ₄ ·2H ₂ O 0.03-0.07g/L.

Preferably, the mineral components and ratios contained in the nutrient solution and the sewage pretreatment solution are: NaH ₂ PO ₄ 0.05g/L, CaCl ₂ ·2H ₂ O 0.3g/L, MgSO ₄ 7H ₂ O 0.3g/L, KHCO ₃ 1.25g/L, FeSO ₄ 0.00625g/L, EDTA 0.00625g/L; the trace element solution includes the following components: EDTA 15g/L, H ₃ BO ₄ 0.014 g/L, MnCl ₂ 4H ₂ O 0.99g/L, CuSO ₄ 5H ₂ O 0.25g/L, ZnSO ₄ 7H ₂ O 0.43g/L, NiCl ₂ 6H ₂ O 0.19g/L, Na ₂ SeO ₄ ·10H ₂ O 0.21 g/L, Na ₂ MoO ₄ ·2H ₂ O 0.22 g/L, Na ₂ WO ₄ ·2H ₂ O 0.05 g/L.

Preferably, the method of denitrifying the liquid collected after anaerobic Feammox treatment is anaerobic ammonium oxidation process, which converts NO ₂ ⁻ in the solution into N ₂ .

In the above technical scheme, the anaerobic reactor is an SBR reactor or a UASB reactor or an EGSB reactor.

Preferably, the added amount of the trace element solution is: 1.25mL trace element solution is added to every liter of nutrient solution, and 1.25mL trace element solution is added to every liter of mixed solution during sewage pretreatment.

Preferably, the operating temperature in the reactor is 30-32° C., and the pH of the mud-water mixture in the reactor is controlled at 7.0-7.5.

The principle of this method is to use Feammox microorganisms to oxidize NH ₄ ⁺ in sewage to NO ₂ ^- under anaerobic conditions. Combined with the existing NO ₂ ^- denitrification treatment process, NH ₄ ⁺ in sewage can be converted into N ₂ So as to realize the denitrification treatment of sewage.

Another object of the present invention is to provide the application of the above-mentioned biological denitrification method based on anaerobic iron ammonia oxidation in sewage denitrification treatment.

The beneficial effects of the present invention are: compared with the traditional aerobic ammonium oxidation or anaerobic ammonium oxidation, the method of the present invention can oxidize NH ₄ ⁺ to NO ₂ ^- under anaerobic conditions. The advanced Anammox process can realize the removal of NH ₄ ⁺ . These two processes are anaerobic processes, and the conditions are easy to control, eliminating the need for O ₂ in the aerobic treatment process and saving costs; Compared with the traditional nitrification-denitrification process, this coupled process has the advantages of lower energy consumption, less carbon source demand, less greenhouse gas emissions (such as N ₂ O), and less NO ₃ ^-production . The method has low energy consumption, low investment and operation costs, and has good application prospects.

Description of drawings

Fig. 1 is in the embodiment of the present invention in the SBR reactor Fe (III) NTA oxidation process flow chart of NH ₄ ⁺ ; Wherein, 1 SBR reactor, 2 hollow interlayers, 3 water bath inlets, 4 water bath outlets, 5 water bath pumps, 6 Water bath, 7 water inlet pump, 8 water inlet tank, 9 water outlet pump, 10 water outlet tank, 11pH meter, 12 online dissolved oxygen analyzer, 13 magnetic stirrer, 14 air outlet.

detailed description

The specific implementation manners of the present invention will be described in detail below in conjunction with the technical solutions and accompanying drawings, but the present invention is not limited to the following examples.

In the laboratory, the SBR reactor with a total reaction volume of 3L in Figure 1 is used to carry out the Fe(III)NTA oxidation of NH ₄ ⁺ in the method of the present invention. Ammonia (Feammox) sludge provenance (from the secondary sedimentation tank sludge of Chongqing Wastewater Treatment Plant). The specific operation steps are as follows:

1. Cultivate and enrich Feammox microorganisms

(1) Sludge pretreatment: Take 1000ml of the aforementioned provenance sludge, wash the sludge with culture medium for 3-5 times under continuous nitrogen aeration, and then use the culture medium to make the volume to 2L to obtain the treated mud-water mixture. The culture solution is obtained by mixing the nutrient solution and the trace element solution, and its composition ratio is to add 1.25mL of the trace element solution to each liter of the nutrient solution.

The content of each component in each liter of nutrient solution is: Fe ₂ (SO ₄ ) ₃ 0.036 grams, (NH ₄ ) ₂ SO ₄ 0.14 grams or NH ₄ Cl 0.113 grams, NTA 0.034 grams, NaH ₂ PO ₄ 0.05 grams, CaCl ₂ ·2H ₂ O 0.3g, MgSO ₄ ·7H ₂ O 0.3g, KHCO ₃ 1.25g, FeSO ₄ 0.00625g, EDTA 0.00625g.

The content of each component in each liter of trace element solution is: _EDTA15g , _H3BO40.014g , MnCl2 _{· 4H2O0.99g} , CuSO4 _{· 5H2O0.25g} , ZnSO4 _{· 7H2O0.43g} , _NiCl2 0.19 g of 6H ₂ O, 0.21 g of Na ₂ SeO ₄ .10H ₂ O, 0.22 g of Na ₂ MoO ₄ .2H ₂ O, and 0.050 g of Na ₂ WO ₄ .2H ₂ O.

(2) Cultivation of Feammox microorganisms: put the 2L mud-water mixture obtained above into the SBR reactor 1 for strain cultivation, the prepared culture solution is stored in the water inlet tank ₈ , and first exposed to N until the dissolved oxygen is 0mg /L, then start to run SBR reactor 1, a cycle of operation is 240min, and run for 210min under agitation (in the first 12min, 1L culture solution is pumped out from the water inlet tank 8 by the inlet pump 7 into the SBR reactor 1) 1. After running for 210 minutes, stop stirring and settling for 18 minutes, then discharge water for 12 minutes (1L of the reacted mud-water mixture is pumped out from the SBR reactor 1 by the discharge pump 9 to the discharge tank 10), so far a treatment cycle is completed. Then, 1L of culture solution is pumped out from the water inlet tank 8 again by the water inlet pump 7 into the SBR reactor 1, and a new treatment cycle is started, and multiple operation cycles are completed in this way. The operating temperature of the reactor is 30-32° C., the pH of the mud-water mixture in the reactor is controlled at 7.0-7.5, and the stirring speed of the magnetic stirrer is 100-200 rpm. Once a day, 200ml of the reacted mud-water mixture was discharged from the SBR reactor 1 and discarded, and then 200ml of new culture solution was added. A total of 90 days of operation (multiple experiments have proved that the purpose of the present invention can be achieved by running for 70-110 days), so that the Feammox microorganisms in the sludge can be enriched, and the obtained sludge can be used for the oxidation of NH ₄ ⁺ in sewage. Other reactors or other equipment can also be used to inoculate and cultivate Feammox microorganisms in sludge. The preservation method of the sludge enriched with Feammox microorganisms is as follows: take the enriched sludge, wash it three times with the culture solution under the condition of continuous exposure to N ₂ , and store the washed sludge in a light-proof In an anaerobic glass bottle, add 0.5L of anaerobic culture solution and seal it, and store it in a refrigerator at 4°C for use as provenance sludge (usually it can be stored for 6 months).

2. Using Feammox microorganisms to treat NH ₄ ⁺ in sewage

In this step, the Feammox microbial treatment of NH ₄ ⁺ in sewage is still carried out in the SBR reactor 1 shown in FIG. 1 . If the culture and enrichment of Feammox microorganisms is carried out in other equipment, the sludge obtained after the enrichment and cultivation of Feammox microorganisms can be connected to the anaerobic reactor for sewage treatment.

(1) Sewage pretreatment: Add the following components in the following ratio to the sewage to be treated containing 2.15mMNH ₄ ⁺ to obtain a sewage pretreatment liquid: add Fe ₂ (SO ₄ ) ₃ 0.036 grams, NTA0.034 per liter of sewage gram, NaH ₂ PO ₄ 0.05g, CaCl ₂ 2H ₂ O 0.3g, MgSO ₄ 7H ₂ O 0.3g, KHCO ₃ 1.25g, FeSO ₄ 0.00625g, EDTA 0.00625g, dissolve and mix well, then add the aforementioned 1.25mL trace element solution mixed; the sewage pretreatment liquid is stored in the water inlet tank 8 in the SBR reactor 1 (if the same SBR reactor used for cultivating Feammox microorganisms mentioned above is used, the original water inlet tank 8 The culture solution in the tank is discharged and replaced with the sewage pretreatment solution), and N is exposed in the water inlet tank 8. The dissolved oxygen in the sewage is ₀ mg/L to reach the anaerobic condition.

(2) discharge 1L of liquid from the SBR reactor 1 after the aforementioned enrichment and cultivation of Feammox microorganisms under the condition of exposure to N ₂ , and then start to carry out sewage treatment: each operating cycle of SBR reactor 1 during sewage treatment is 240min, stirring running for 210 minutes under normal conditions (in the first 12 minutes, 1L of sewage pretreatment liquid is pumped out from the water inlet tank 8 by the water inlet pump 7 into the SBR reactor 1), after running for 210 minutes, the stirring and sedimentation are stopped for 18 minutes, and the water is discharged for 12 minutes (by the water outlet pump 9 1L of treated sewage is pumped out from the SBR reactor 1 to the outlet tank 10); thus far, a treatment cycle is completed. Next, the water inlet pump 7 pumps out 1L of sewage pretreatment liquid from the water inlet tank 8 again into the SBR reactor 1 to start a new treatment cycle, so that the sewage can be treated continuously in this cycle. The operating temperature of the reactor is 30-32° C., the pH of the mud-water mixture in the reactor is controlled at 7.0-7.5, and the stirring speed of the magnetic stirrer is 100-200 rpm. Once a day, 200ml of the reacted mud-water mixture is discharged from the SBR reactor 1 and discarded, and then 200ml of the aforementioned sewage pretreatment solution is added.

The oxidation effect of NH ₄ ⁺ was measured during the sewage treatment process. The experiment ran continuously for 4 hours, and the NH ₄ ⁺ in the sewage to be treated was 2.15mM. During the continuous 4-hour test, the average oxidation rate of NH ₄ ⁺ was 156.16mgN/ (L·d), the average accumulation rate of NO ₂ ⁻ in the treated water collected in the outlet tank 10 is also 156.16 mgN/(L·d).

3. Anaerobic ammonium oxidation treatment of sewage after anaerobic Feammox treatment

The effluent collected in the effluent tank 10 after the aforementioned anaerobic iron ammonium oxidation treatment is subjected to anaerobic ammonium oxidation treatment. The anaerobic ammonium oxidation process is a very mature process at present and will not be described in detail here. The NO ₂ ^- in the water is converted into N ₂ through the anaerobic ammonium oxidation process, and the anaerobic removal of NH ₄ ⁺ in the sewage is realized.

Through experimentation, in the nutrient solution described in the inventive method, sewage pretreatment liquid, the distribution ratio of each component in the trace element solution also can realize the inventive method in the following scope: described nutrient solution and sewage pretreatment liquid comprise Mineral components: NaH ₂ PO ₄ 0.04～0.06g/L, CaCl ₂ 2H ₂ O 0.2～0.4g/L, MgSO ₄ 7H ₂ O 0.2～0.4g/L, KHCO ₃ 1.0～1.5g /L, FeSO ₄ 0.0060~0.0065g/L, EDTA 0.0060~0.0065g/L; Fe ₂ (SO ₄ ) ₃ 0.032~0.04g, (NH ₄ ) ₂ SO ₄ 0.13~0.15g in the nutrient solution Or 0.11-0.12 grams of NH ₄ Cl, 0.03-0.034 grams of NTA; 0.032-0.04 grams of Fe ₂ (SO ₄ ) ₃ and 0.03-0.034 grams of NTA in the sewage pretreatment solution; the trace element solution Contains the following components: _EDTA13 ～17g/L, _H3BO40.010 ～0.016g/L, MnCl2 _{· 4H2O0.90} ～1.10g/L, CuSO4 _{· 5H2O0.20} ～0.30g/L L, ZnSO ₄ 7H ₂ O 0.35～0.50g/L, NiCl ₂ 6H ₂ O 0.15～.025g/L, Na ₂ SeO ₄ 10H ₂ O 0.15～0.26g/L, Na ₂ MoO ₄ 2H ₂ O 0.17～0.27g/L, Na ₂ WO ₄ 2H ₂ O0.03～0.07g/L;

The method of the invention realizes the conversion of NH ₄ ⁺ in sewage into NO ₂ ^- under anaerobic and anaerobic conditions, and combines this process with the anaerobic ammonium oxidation process in the sewage treatment system to realize the conversion of NH under anaerobic conditions. ₄ ⁺ final conversion into _N2 , compared with the traditional nitrification-denitrification process, this coupled process will have lower energy consumption, less carbon source demand, and less greenhouse gas emissions (such as _N2O ) , less NO ₃ -production ^and other advantages.

Claims (10)

1. A biological denitrification method based on anaerobic iron ammonia oxidation, it is characterized in that, comprises the steps: in anaerobic reactor, add the sludge that contains Feammox microorganism, ammoniacal sewage is passed in reactor, utilizes Feammox (III) NTA oxidizes NH ₄ ⁺ in sewage to generate NO ₂ ^- , and then performs denitrification treatment. The specific steps are as follows: 1. Cultivate and enrich Feammox microorganisms 1) Sludge pretreatment: mix the provenance sludge containing Feammox microorganisms with a culture solution to obtain a mud-water mixture, and the culture solution is obtained by mixing a nutrient solution and a trace element solution, and the composition ratio is as follows: Add 1.0-1.5mL trace element solution; the nutrient solution contains 0.16-0.20mM Fe(III)NTA, 2.00-2.30mM NH ₄ ⁺ and minerals; 2) Cultivation of Feammox microorganisms: Connect the aforementioned mud-water mixture into an anaerobic reactor, first expose to _N2 until the dissolved oxygen in the mud-water mixture is 0mg/L, then start the reactor, add half the volume of the mud-water mixture for the aforementioned cultivation The solution runs for 180-240 minutes, then stops running for 15-25 minutes, and discharges the supernatant after precipitation. The discharge volume is the same as the volume of the added culture solution. At this point, a treatment cycle is completed; Culture liquid, start a new treatment cycle, and complete multiple operation cycles in this way; the operating temperature of the reactor is 30-35°C, and the pH of the mud-water mixture in the reactor is controlled at 7.0-8.0; the reaction is discharged from the reactor once a day One-fifteenth of the total volume of the final mud-water mixture is discarded, and then refilled with a new culture solution of the same volume as the discarded solution; a total of 70 to 110 days of operation; 2. Using Feammox microorganisms to treat NH ₄ ⁺ in sewage 1) Sewage pretreatment: Add 0.16-0.20mMFe(III)NTA to the ammonia-containing sewage to be treated, dissolve and mix the minerals to obtain a mixed solution, and then add trace elements at a rate of 1.0-1.5mL of trace element solution per liter of the mixed solution The element solution is mixed to obtain the sewage pretreatment liquid; 2) Drain half of the volume of the mud-water mixture obtained after enriching and cultivating Feammox microorganisms, and then add it to the anaerobic reactor for sewage treatment: add the same volume of the mud-water mixture in the reactor as the aforementioned sewage pretreatment The solution runs for 180-240 minutes, then stops to settle for 15-25 minutes, discharges the solution with the same volume as the sewage pretreatment solution added after the precipitation and collects the liquid, and completes a treatment cycle; Volume of sewage pretreatment liquid, start a new treatment cycle, so that the sewage treatment can be carried out continuously; the operating temperature of the reactor is 30-35 ℃, and the pH of the mud-water mixture in the reactor is controlled at 7.0-8.0; once a day Discard one-fifteenth of the total volume of the reacted mud-water mixture from the reactor, and then refill the same volume of sewage pretreatment liquid as the effluent; so far, the conversion of NH ₄ ⁺ in sewage into NO _2- the process of; 3. The liquid collected after the aforementioned anaerobic Feammox treatment is subjected to denitrification treatment. 2. The biological denitrification method based on anaerobic iron ammonia oxidation as claimed in claim 1, wherein the concentration of Fe(III)NTA in the nutrient solution is 0.18mM, and the concentration of NH ₄ ⁺ is 2.15mM , the concentration of Fe(III)NTA in the sewage pretreatment liquid is 0.18mM. 3. the biological denitrification method based on anaerobic iron ammonia oxidation as claimed in claim 1, is characterized in that, described Fe (III) NTA is by Fe ₂ (SO ₄ ) ₃ and NTA by the molar ratio of 1:1 Yes, the NH ₄ ⁺ is derived from ammonium sulfate or ammonium chloride. 4. The biological denitrification method based on anaerobic iron ammonium oxidation as claimed in claim 1, wherein the mineral components and proportions contained in the nutrient solution and the sewage pretreatment solution are: NaH ₂ PO ₄ 0.04～0.06g/L, CaCl ₂ 2H ₂ O 0.2～0.4g/L, MgSO ₄ 7H ₂ O 0.2～0.4g/L, KHCO ₃ 1.0～1.5g/L, FeSO ₄ 0.0060 ～0.0065g/L, EDTA0.0060～0.0065g/L; the trace element solution includes the following components: EDTA13～17g/L, H ₃ BO ₄ 0.010～0.016g/L, MnCl ₂ ·4H ₂ O0.90～1.10g/L, CuSO ₄ 5H ₂ O0.20～0.30g/L, ZnSO ₄ 7H ₂ O0.35～0.50g/L, NiCl ₂ 6H ₂ O0.15～.025g/L , Na ₂ SeO ₄ ·10H ₂ O 0.15-0.26 g/L, Na ₂ MoO ₄ ·2H ₂ O 0.17-0.27 g/L, Na ₂ WO ₄ ·2H ₂ O 0.03-0.07 g/L. 5. The biological denitrification method based on anaerobic iron ammonium oxidation as claimed in claim 4, characterized in that, the mineral components and proportions contained in the nutrient solution and the sewage pretreatment solution are: NaH ₂ PO ₄ 0.05g/L, CaCl ₂ 2H ₂ O 0.3g/L, MgSO ₄ 7H ₂ O 0.3g/L, KHCO ₃ 1.25g/L, FeSO ₄ 0.00625g/L, EDTA 0.00625g/L; The trace element solution includes components at the following concentrations: EDTA 15g/L, H ₃ BO ₄ 0.014g/L, MnCl ₂ 4H ₂ O 0.99g/L, CuSO ₄ 5H ₂ O 0.25g/L, ZnSO ₄ . 7H ₂ O 0.43g/L, NiCl ₂ 6H ₂ O 0.19g/L, Na ₂ SeO ₄ 10H ₂ O 0.21g/L, Na ₂ MoO ₄ 2H ₂ O 0.22g/L, Na ₂ WO ₄ 2H ₂ O 0.05g/L. 6. the biological denitrification method based on anaerobic iron ammonium oxidation as claimed in claim 1, is characterized in that, the method that the liquid collected after the anaerobic Feammox treatment is carried out denitrification treatment is anaerobic ammonium oxidation process treatment , to convert NO ₂ ^- in the solution into N ₂ . 7. The biological denitrification method based on anaerobic iron ammonia oxidation as claimed in claim 1, wherein the anaerobic reactor is an SBR reactor or a UASB reactor or an EGSB reactor. 8. The biological denitrification method based on anaerobic ferric ammonium oxidation as claimed in claim 1, characterized in that, the added amount of said trace element solution is: add 1.25mL trace element solution in every liter of nutrient solution, during sewage pretreatment Add 1.25mL trace element solution per liter of mixed solution. 9 . The biological denitrification method based on anaerobic ferric ammonium oxidation as claimed in claim 1 , wherein the operating temperature in the reactor is 30-32° C., and the pH of the mud-water mixture in the reactor is controlled at 7.0-7.5. 10. Application of the biological denitrification method based on anaerobic iron ammonia oxidation in sewage denitrification treatment as described in any one of claims 1 to 8.