Method for reducing total nitrogen in nitrogenous wastewater to ultralow concentration

Abstract

The invention belongs to the technical field of nitrogen-containing wastewater biological treatment, and relates to a method for reducing total nitrogen in nitrogen-containing wastewater to ultralow concentration, the method combines nitrification with Biotrar-DN, the formed system does not need a sedimentation tank and a sludge discharge system, the occupied area is small, the investment is low, and the method is suitable for industrial production. The TN of lake water desilting water and / or demolition lake water, aquaculture wastewater, industrial wastewater, municipal wastewater and river channel water can be reduced to 1 mg / L or below, only simple backwashing is needed, the residence time is short, daily operation and maintenance are simple, and the operation cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of biological treatment of nitrogen-containing wastewater, and particularly relates to a method for reducing total nitrogen in nitrogen-containing wastewater to an ultra-low concentration. Background Art

[0002] Water resources, especially fresh water resources that can be used by humans, are very scarce today as the world's per capita resource consumption accelerates. This makes it more important to protect limited fresh water resources and treat polluted water bodies. The nitrogen-containing pollutants in sewage are mainly organic nitrogen (protein, urea, etc.), ammonia nitrogen (NH4 + -N), nitrite nitrogen (NO2 - -N) and nitrate nitrogen (NO3 - -N) and other forms. Nitrogen exists in every corner of nature and is of great significance to every aspect of the ecosystem. However, excessive nitrogen input will cause environmental pollution and endanger the health of the water ecosystem. Too much nitrogen will cause a large number of algae to reproduce, causing algal blooms in rivers and lakes and red tides in seawater, which not only affects the appearance, but also consumes a large amount of dissolved oxygen in the water, causing a decrease in the dissolved oxygen concentration in the water, a large number of aquatic organisms to die, and the water quality of the water body to deteriorate and become black and smelly. At the same time, NO3 - -N and NO2 - -N exceeding the standard also has a great harmful effect on humans and aquatic life.

[0003] In order to remove total nitrogen from water, physical, chemical and biological methods are generally used. Physical technology mainly removes pollutants through physical means, such as removing bottom sludge, diverting water for dilution, mechanical algae removal, etc. Mud removal is to remove pollutants from the river system, which can greatly reduce the contribution of bottom sludge to the pollution of the overlying water body, thereby improving water quality. Water diversion is to introduce clean water sources upstream or near the polluted river through the regulation of water conservancy facilities such as gates and pumping stations to improve the water quality of the downstream polluted river. Mechanical algae removal uses filters, screens, etc. to quickly salvage algae on the surface. The physical method has simple process equipment, easy operation, high cost, and only treats the symptoms but not the root cause. It generally does not meet the emission standards and is mostly used as pretreatment or emergency measures.

[0004] The chemical method is to remove pollutants in the water by adding appropriate chemical agents to react with pollutants in the water to generate gas, precipitate and separate from the water, or degrade and transform into low-toxic or non-toxic chemical forms, so as to achieve the purpose of removing pollutants in the water. Generally, coagulation and sedimentation, addition of chemical agents to kill algae, addition of lime to denitrify, etc. are used. For low ammonia nitrogen wastewater, adsorption method, breakpoint chlorination method, ion exchange method, etc. can also be used. The chemical method has the most obvious temporary effect, but it is very easy to cause secondary pollution of the water body, and the cost of use is relatively high. The effect is not lasting, and it only treats the symptoms but not the root cause. Usually, chemical agents need to be added repeatedly, the cost of treatment is high, and long-term use will also cause water ecological imbalance. It is generally used as an auxiliary or emergency control technology.

[0005] It can be seen that physical and chemical methods are usually expensive, only treat the symptoms but not the root cause, and are prone to introduce other by-products, causing secondary pollution to the water body. Biotechnology mainly coordinates environmental pollution factors outside the system by improving the self-regulation ability of the ecosystem, improving system functions, and realizing feedback regulation mechanisms. Biotechnology is a biological measure that uses specific biological plants, microorganisms or protozoa to absorb, transform, remove or degrade environmental pollutants to achieve environmental purification and ecological effect restoration. It mainly uses in-situ remediation, complete degradation, low cost, and can be combined with a variety of technologies. Biological methods are the mainstream process in the field of wastewater denitrification because they are economical and efficient, and the treatment process does not cause secondary pollution. They are environmentally friendly and sustainable.

[0006] Biotechnology includes natural ecological purification and microbial treatment. Natural ecological purification includes the purposeful introduction of excellent aquatic plant species or the restoration of the original damaged plants, promoting the recovery of aquatic vegetation in degraded water ecosystems, and achieving a virtuous cycle of water ecosystems. It is suitable for water bodies with low pollution levels and is green and environmentally friendly. It is suitable for water bodies with low pollution levels, has strong specificity, long removal time, and occupies a large area. The harvesting and placement of plants in the later stage need to be solved.

[0007] Microbial treatment: Microbial agents can be directly added to the water body for treatment, but the amount of addition is usually large and needs to be repeated. Therefore, the traditional activated sludge method and biofilm method are mainly used to colonize microorganisms to prevent loss. The activated sludge method is now widely used to treat various wastewaters. It uses the activated sludge suspended in the sewage to adsorb and decompose organic matter or certain inorganic salts in the sewage. The biofilm method is a new type of sewage treatment technology that organically combines membrane filtration technology with the activated sludge method. It uses a membrane separation device to effectively intercept the activated sludge and macromolecular organic matter in the biochemical reaction tank, increase the sludge concentration and organic matter degradation rate in the biochemical reaction tank, and improve the effluent water quality. In recent years, due to the continuous in-depth research and improvement of the biochemical reaction mechanism of microorganisms by researchers, many new processes have emerged, making the application scope of this technology increasingly wide and the treatment efficiency has been significantly improved. Pollutants can be completely removed by microbial treatment, with little impact on the environment, short repair time, small capital investment, simple in-situ repair operation, low energy consumption, no secondary pollution, and can restore the self-purification capacity of the water body.

[0008] Traditional biological denitrification processes include oxidation ditch, O / A, A / O, A 2 O, SBR, MBR, etc., all rely on nitrification-denitrification. Nitrification requires aeration, which increases energy consumption, and denitrification requires the addition of carbon sources, which increases operating costs. They have poor treatment effects on low C / N sewage, long residence time, large footprint, large sludge production, complex operation and management, and it is difficult to achieve a low concentration in the effluent.

[0009] New denitrification processes include simultaneous nitrification and denitrification, anaerobic ammonium oxidation, short-term nitrification-denitrification process, heterotrophic nitrification-aerobic denitrification, semi-nitrification-anaerobic ammonium oxidation process, autotrophic denitrification, etc. Most of the new processes have the advantages of saving energy and land, reducing carbon source dosage, reducing carbon emissions and sludge production; however, in the new denitrification process, simultaneous nitrification-denitrification is an integrated reaction, with complex bacterial distribution, large oxygen influence, and unstable process operation; anaerobic ammonium oxidation culture has strict requirements and needs to provide stable NO2-N, and generally needs to be combined with other processes, such as setting up a partial nitrification process at the front end of the project to ensure the high denitrification efficiency of the system; the short-term nitrification-denitrification process needs to inhibit NOB from enriching AOB, which is difficult to control; heterotrophic nitrification-aerobic denitrification has high requirements for carbon source and aeration rate, which increases energy consumption and operating costs. Summary of the invention

[0010] The purpose of the present invention is to provide a method for reducing the total nitrogen in nitrogen-containing wastewater to an ultra-low concentration in response to the problems existing in the prior art. The method combines nitrification with Biotra-DN. The formed system does not require a sedimentation tank and a sludge discharge system, has a small footprint, and has low investment. It can reduce the TN in the wastewater to below 1 mg / L, only requires simple backwashing, has a short residence time, is simple in daily operation and maintenance, and has low operating costs.

[0011] To this end, the present invention provides a method for reducing total nitrogen in wastewater to an ultra-low concentration, comprising:

[0012] Step A, in a reaction tank I of a nitrification system, a nitrifying composite microbial preparation is mixed and cultured with a carrier I and nitrogen-containing wastewater to obtain a carrier I with a nitrifying composite microbial membrane stably attached thereto;

[0013] Step B, directly introducing nitrogen-containing wastewater into the reaction tank I of the nitrification system at full load to degrade ammonia nitrogen, thereby obtaining primary ammonia nitrogen-reduced wastewater;

[0014] Step C, in the reaction tank II of the Biotra-DN system, the Biotra-DN composite microbial preparation is mixed and cultured with the carrier II and the primary ammonia nitrogen reduction wastewater to obtain the carrier II with the Biotra-DN composite biofilm stably attached;

[0015] Step D, directly introducing the primary ammonia nitrogen reduction wastewater into the reaction tank II of the Biotra-DN system at full load to degrade the total nitrogen to obtain dischargeable water;

[0016] Among them, the ammonia nitrogen of the first-level ammonia nitrogen reduction wastewater is less than 0.5 mg / L; the total nitrogen of the dischargeable water is less than 1 mg / L.

[0017] According to some embodiments of the present invention, step A comprises:

[0018] Step S1, adding the nitrifying composite microorganism preparation into a reaction tank I containing a carrier I, so that the preparation is evenly distributed on the carrier I, and adding nitrogen-containing wastewater into the reaction tank I, so that the water level rises to just immerse the carrier I, to obtain a mixture of the nitrifying composite microorganism preparation-carrier I-nitrogen-containing wastewater;

[0019] Step S2, aeration, culturing the mixture of nitrifying composite microorganism preparation-carrier I-nitrogen-containing wastewater, allowing the nitrifying composite microorganism group to stably attach to carrier I to form a biofilm, obtaining carrier I with a stably attached nitrifying composite microbial film, and draining the liquid in reaction tank I.

[0020] According to some other embodiments of the present invention, step C comprises:

[0021] Step T1, adding the Biotra-DN composite microbial preparation to the reaction tank II containing the carrier II, so that it is evenly distributed on the carrier II, and adding the primary ammonia nitrogen reduction wastewater to the reaction tank II, so that the water level rises to just immerse the carrier II, and obtains a mixture of Biotra-DN composite microbial preparation-carrier II-primary ammonia nitrogen reduction wastewater;

[0022] Step T2, bottom stirring or internal circulation, culturing the Biotra-DN composite microbial preparation-carrier II-primary ammonia nitrogen reduction wastewater mixture, allowing the Biotra-DN composite microbial community to stably attach to carrier II to form a biofilm, obtaining carrier II with stably attached Biotra-DN composite microbial film, and draining the liquid in reaction tank II.

[0023] Preferably, in steps S2 and T2, the water temperature is maintained between 18 and 30° C.; preferably, the culturing time is 3 to 5 days.

[0024] In the present invention, the nitrifying composite microbial preparation comprises nitrifying bacteria, biological additive I and nutrient agent I.

[0025] Preferably, the nitrifying bacteria include Nitrosomonas and / or Nitrobacter.

[0026] According to the present invention, the biological additive I includes microcarrier I, growth promoting factor I, and protective agent I.

[0027] In some embodiments of the present invention, the microcarrier I comprises one or more of talc powder, pumice powder, zeolite powder, powdered activated carbon, bamboo charcoal powder, white carbon black, diatomaceous earth, polycaprolactone and calcium alginate.

[0028] In some embodiments of the present invention, the growth promoting factor I includes trace metal elements and / or vitamins.

[0029] In some embodiments of the present invention, the protective agent I comprises one or more of glycerol, trehalose, nitrite and nitrate;

[0030] In some embodiments of the present invention, the nutrient agent I is a substance I containing CNP, which includes one or more of glucose, urea, peptone and potassium dihydrogen phosphate;

[0031] Preferably, the dosage ratio of nitrifying bacteria, biological aid I and nutrient agent I in the nitrifying composite microbial preparation is 1-5:1-5:1-5.

[0032] According to the present invention, the Biotra-DN composite microbial preparation comprises denitrifying bacteria, biological additive II and nutrient II

[0033] Preferably, the denitrifying bacteria include Pseudomonas and / or Bacillus;

[0034] According to the present invention, the biological additive II includes microcarrier II, growth promoting factor II and protective agent II.

[0035] In some embodiments of the present invention, the microcarrier II includes one or more of Fumei powder, powdered activated carbon, bamboo charcoal powder, white carbon black, diatomaceous earth, polycaprolactone, calcium alginate, cassava starch and corn starch.

[0036] In some embodiments of the present invention, the growth factor II includes trace metal elements and / or vitamins.

[0037] In some embodiments of the present invention, the protective agent II includes glycerol and / or trehalose;

[0038] In some embodiments of the present invention, the nutrient agent II is a substance II containing CNP, which includes one or more of glucose, urea, peptone and potassium dihydrogen phosphate.

[0039] Preferably, the dosage ratio of denitrifying bacteria, biological aid II and nutrient II in the Biotra-DN composite microbial preparation is 1-5:1-5:1-5.

[0040] According to the present invention, the nutrient agent I and the nutrient agent II are the same or different; preferably, the mass ratio of carbon, nitrogen and phosphorus in the nutrient agent I and the nutrient agent II is 100:5:1.

[0041] In some embodiments of the present invention, the carrier I comprises a bio-rope; preferably, the bio-rope is composed of PET nano-modified composite fibers, and more preferably, the bio-rope has a diameter of 80-85 mm, a specific surface area of ​​>0.55 m2 / g, a dry weight of >50 g / m, and a breaking strength of >2800 N.

[0042] In the present invention, the carrier II includes activated carbon and / or activated coke.

[0043] In some embodiments of the present invention, the activated carbon is coal-made granular activated carbon; preferably, the activated carbon has an iodine value of 600-1100 mg / g, a strength of >90%, and a specific surface area of ​​500-1200 m 2 / g.

[0044] In some embodiments of the present invention, the activated coke has an iodine value of 400-800 mg / g, a strength of more than 90%, and a specific surface area of ​​400-800 m 2 / g.

[0045] In some embodiments of the present invention, the nitrogen-containing wastewater includes one or more of lake desilting water, lake demolition water, aquaculture wastewater, industrial wastewater, municipal wastewater and river water.

[0046] The method of the present invention combines nitrification with Biotra-DN (coupling). The inside of the nitrification system is a carrier inoculated with self-developed nitrifying bacteria, which mainly converts ammonia nitrogen into nitrite nitrogen in an aerobic environment and then into nitrate nitrogen. The inside of the Biotra-DN system is a specially selected activated carbon inoculated with a self-developed denitrifying bacterial agent. In an anaerobic environment, heterotrophic denitrifying bacteria using organic matter as a carbon source degrade nitrate nitrogen into nitrogen gas; in the system formed by combining nitrification with Biotra-DN (coupling), the bacterial agent and the carrier are added once, and no subsequent addition is required. Only the nitrification system needs aeration. The coupled system can efficiently treat nitrogen-containing wastewater. When TN reaches the requirement of <1mg / L, the system produces little sludge, does not require a sedimentation tank and a sludge discharge system, and the entire system occupies a small area, has low investment, requires only simple backwashing, has a short residence time (HRT), is simple in daily operation and maintenance, has low operating costs, is green and environmentally friendly, has no secondary pollution, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be further described below in conjunction with the accompanying drawings.

[0048] Figure 1 It is a schematic diagram of the device for removing total nitrogen from nitrogen-containing wastewater used in the present invention.

[0049] Figures 2 to 8 The total nitrogen removal results of the nitrogen-containing wastewater in Examples 1 to 7 are shown respectively. DETAILED DESCRIPTION

[0050] To make the present invention easy to understand, the present invention will be described in detail below in conjunction with examples. However, before describing the present invention in detail, it should be understood that the present invention is not limited to the specific embodiments described. It should also be understood that the terms used herein are only for describing specific embodiments and are not intended to be limiting.

[0051] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, preferred methods and materials are now described.

[0052] I. Terminology

[0053] The term "dischargeable water" used in the present invention refers to water that meets the Class III discharge standard in the surface water environmental quality discharge standard (GB 3838-2002).

[0054] The term "self-fermenting denitrifying bacteria" mentioned in the present invention refers to microbial denitrifying bacteria species selected from nature that can remove nitrate-nitrogen in water. They are professionally formulated with biological additives and nutrients to form self-fermenting denitrifying bacteria agents, which are mainly used to start or improve the nitrate-nitrogen removal capacity of sewage treatment systems.

[0055] The term "Biotra-DN" used in the present invention is a trademark of Shanghai Diyu Technology Co., Ltd., which is the anoxic denitrification process in the "high-efficiency biological activated carbon filter process" Biotra. The Biotra process integrates "adsorption-concentration-online regeneration" and is a combination technology of special microbial flora and specially screened biological activated carbon. This technology can effectively remove pollutants such as difficult-to-degrade COD, ammonia nitrogen or total nitrogen in water. It is green and environmentally friendly without secondary pollution, and is divided into aerobic and anoxic processes. Biotra-DN is the anoxic denitrification process.

[0056] The term "ultra-low concentration" in the present invention means that the TN of water is reduced to 1 mg / L.

[0057] The term "EBCT" (Empty Bed Contact Time) used in the present invention refers to the time required for water to flow through the space occupied by the filter bed assuming that no filter bed is added, and the unit is min.

[0058] The term "nitrogen-containing wastewater" in the present invention refers to wastewater containing ammonia nitrogen and total nitrogen, which can be used interchangeably with "nitrogen-containing wastewater raw water", which includes but is not limited to one or more of lake dredging water, lake demolition water, aquaculture wastewater, industrial wastewater, municipal wastewater and river water.

[0059] The terms "wastewater" and "sewage" in the present invention can be used interchangeably.

[0060] The terms "about," "approximately," "substantially," and "substantially," as used herein, when used in conjunction with a range of an element, concentration, temperature, or other physical or chemical property or characteristic, cover variations that may exist in the upper and / or lower limits of the range of the property or characteristic, including variations caused, for example, by rounding, measurement methods, or other statistical variations. For example, as used herein, with respect to numerical values ​​associated with amounts, weights, etc., "about" is defined as all numerical values ​​plus or minus 1% for each specific value. For example, the term "about 10%" should be understood as "9% to 11%."

[0061] II. Implementation Plan

[0062] As mentioned above, the traditional biological denitrification process has poor treatment effect on nitrogen-containing sewage, long residence time, large floor space, large sludge production, complex operation and management, and it is difficult to achieve a low concentration of effluent. Although most new processes have the advantages of saving energy and land, reducing carbon source dosage, reducing carbon emissions and sludge production; however, the synchronous nitrification-denitrification in the new denitrification process is an integrated reaction, the bacterial distribution is complex, the oxygen influence is large, and the process operation is unstable; anaerobic ammonia oxidation culture is demanding, and stable NO2-N needs to be provided. It generally needs to be combined with other processes, such as setting up a partial nitrification process at the front end of the project to ensure the high denitrification efficiency of the system; the short-range nitrification-denitrification process needs to suppress NOB enrichment AOB, which is difficult to control; heterotrophic nitrification-aerobic denitrification has high requirements for carbon source and aeration rate, which increases energy consumption and operating costs. In view of this, the inventors have conducted extensive and in-depth research on nitrogen-containing sewage treatment technology.

[0063] The inventors have found that by combining nitrification with Biotra-DN (coupling), the nitrification system contains a biological rope inoculated with self-fermenting nitrifying bacteria, which mainly converts ammonia nitrogen into nitrite nitrogen and then into nitrate nitrogen in an aerobic environment. The Biotra-DN system contains modified activated carbon inoculated with a self-developed denitrifying bacterial agent, and in an anaerobic environment, heterotrophic denitrifying bacteria using organic matter as a carbon source degrade nitrate nitrogen into nitrogen gas. In the system formed by combining nitrification with Biotra-DN (coupling), the bacterial agent and the carrier are added at one time, and no subsequent addition is required. The nitrification system only requires aeration, and Biotra-DN can treat TN in nitrogen-containing sewage to below 1 mg / L.

[0064] Therefore, the sewage treatment system of the present invention is composed of a nitrification system 1 and a Biotra-DN system 2 coupled in series, such as Figure 1 shown.

[0065] The nitrification system 1 is composed of a raw water tank 11, a nitrification system water inlet pump 12, a reaction tank I 13 and an intermediate water storage tank 21 connected in series in sequence; the raw water tank 11 is connected to the bottom feed port 131 of the reaction tank I through the nitrification system water inlet pump 12; the upper discharge port 132 of the reaction tank I is connected to the intermediate water storage tank 21 through a pipeline. An air inlet 133 is also provided at the bottom of the reaction tank I, which is connected to the nitrification system air inlet pump 14.

[0066] The Biotra-DN system is composed of an intermediate water storage tank 21, a Biotra-DN system water inlet pump 22, a reaction tank II 23 and a water production tank 24 connected in series in sequence; the intermediate water storage tank 21 is connected to the bottom feed port I 231 of the reaction tank II through the Biotra-DN system water inlet pump 22; the upper discharge port 232 of the reaction tank II is connected to the water production tank 24. The reaction tank II is also provided with a carbon source dosing device 26, which is connected to the bottom feed port II 233 of the reaction tank II through a carbon source feed pump 25.

[0067] The reaction tank I 13 of the nitrification system 1 is connected to the reaction tank II 23 of the Biotra-DN system 2 through the intermediate water storage tank 21 and the Biotra-DN system water inlet pump 22 .

[0068] There is no particular limitation on the reaction tank I and the reaction tank II in the present invention, and conventional filter tanks in the art can be used as long as the present invention can be realized; for example, the filter tank in Chinese patent CN 113185005 A can be used.

[0069] Correspondingly, the method for removing total nitrogen in water involved in the present invention comprises the following steps:

[0070] (1) adding the nitrifying composite microbial preparation into the reaction pool I containing the biological rope so that the preparation is evenly distributed on the carrier I, and adding the nitrogen-containing wastewater raw water into the reaction pool I so that the water level rises to just immerse the carrier I, thereby obtaining a mixture of the nitrifying composite microbial preparation-carrier I-nitrogen-containing wastewater;

[0071] (2) maintaining the water temperature between 18 and 30° C. and aerating, culturing the mixture of the nitrifying composite microbial preparation-carrier I-nitrogen-containing wastewater for 3 to 5 days, so that the nitrifying composite microbial community is stably attached to the carrier I to form a biofilm, obtaining the carrier I with a stably attached nitrifying composite microbial film, and draining the liquid in the reaction tank I.

[0072] (3) directly introducing nitrogen-containing wastewater at full load into the reaction tank I of the nitrification system to degrade ammonia nitrogen, thereby obtaining first-level ammonia nitrogen-reduced wastewater with ammonia nitrogen less than 0.5 mg / L;

[0073] (4) adding the Biotra-DN composite microbial preparation into the reaction tank II containing the carrier II so that it is evenly distributed on the carrier II, and adding the primary ammonia nitrogen reduction wastewater into the reaction tank II so that the water level rises to just immerse the carrier II, thereby obtaining a mixture of the Biotra-DN composite microbial preparation-carrier II-primary ammonia nitrogen reduction wastewater;

[0074] (5) The mixture of Biotra-DN composite microbial preparation-carrier II-primary ammonia nitrogen reduction wastewater is cultured by stirring at the bottom or circulating internally, so that the Biotra-DN composite microbial community is stably attached to carrier II to form a biofilm, and carrier II with a stably attached Biotra-DN composite microbial film is obtained, and the liquid in reaction tank II is drained.

[0075] (6) The primary ammonia nitrogen reduction wastewater is directly introduced into the reaction tank II of the Biotra-DN system at full load to degrade the total nitrogen and obtain dischargeable water with a total nitrogen content of <1 mg / L.

[0076] In the present invention, the nitrifying composite microbial preparation comprises nitrifying bacteria, biological additive I and nutrient agent I.

[0077] In the present invention, the nitrifying bacteria are obtained by adding aerobic pool sludge taken from a biochemical pool of a sewage treatment plant in Wujin Textile Industrial Park, Changzhou City, Jiangsu Province, into water containing ammonia nitrogen, and culturing for 5 days under aeration to obtain extraction. The results of bacterial flora analysis show that the nitrifying bacteria mainly include Nitrosomonas and Nitrobacter, and the ratio of Nitrosomonas to Nitrobacter is 3:5 (quantity ratio); wherein the water containing ammonia nitrogen is wastewater prepared by using river water to obtain an ammonia nitrogen concentration of 100 mg / L.

[0078] According to the present invention, the biological additive I includes microcarrier I, growth promoting factor I, and protective agent I.

[0079] In the present invention, the microcarrier I is mainly used for bacteria that can attach to biofilms, providing a place for bacterial growth and quickly forming biofilms; preferably, the microcarrier I includes but is not limited to one or more of talcum powder, pumice powder, zeolite powder, powdered activated carbon, bamboo charcoal powder, white carbon black, diatomaceous earth, polycaprolactone and calcium alginate.

[0080] In the present invention, the growth-promoting factor I can provide trace components required for bacterial growth; preferably, the growth-promoting factor I includes one or more of all trace metal elements and / or one or more of all vitamins.

[0081] In the present invention, the protective agent I can put the bacteria in a dormant state, maintain a certain activity of the bacteria, prevent the bacteria from dying, and prolong the stability time of the bacterial agent; preferably, the protective agent I includes one or more of glycerol, trehalose, nitrite and nitrate.

[0082] In some embodiments of the present invention, the nutrient agent I is a substance I containing CNP, which includes one or more of glucose, urea, peptone and potassium dihydrogen phosphate.

[0083] Preferably, the dosage ratio of nitrifying bacteria, biological aid I and nutrient agent I in the nitrifying composite microbial preparation is 1-5:1-5:1-5.

[0084] In some specific examples of the present invention, the nitrifying composite microbial preparation is composed of Nitrosomonas, Nitrobacter, talcum powder, pumice powder, zeolite powder, diatomaceous earth, glycerol, nitrite, nitrate, glucose, urea, potassium dihydrogen phosphate, and peptone; wherein, Nitrosomonas and Nitrobacter are extracted from natural water, and the remaining biological additives, nutrients, etc. are purchased from common markets.

[0085] In some specific preferred examples of the present invention, the nitrifying composite microbial preparation is composed of Nitrosomonas, Nitrobacter, talc, pumice powder, zeolite powder, diatomaceous earth, glycerol, nitrite, nitrate, glucose, urea, potassium dihydrogen phosphate, and peptone in a ratio of 3:5:5:4:4:1:1:2:2:1:1:1:1.

[0086] According to the present invention, the Biotra-DN composite microbial preparation comprises denitrifying bacteria, biological additive II and nutrient II.

[0087] In the present invention, the denitrifying bacteria are composed of Pseudomonas stutzeri DY-2316 (strain collection number is GCMCC No. 28879) and Bacillus licheniformis DY-2306 (strain collection number is CGMCC No. 28526). Moreover, Pseudomonas stutzeri: Bacillus licheniformis = 5:5 (quantity ratio).

[0088] According to the present invention, the biological additive II includes microcarrier II, growth promoting factor II and protective agent II.

[0089] In the present invention, the microcarrier II is mainly used for bacteria that can attach to biofilms, providing a place for bacterial growth and quickly forming biofilms; preferably, the microcarrier II includes one or more of Fumei powder, powdered activated carbon, bamboo charcoal powder, white carbon black, diatomaceous earth, polycaprolactone, calcium alginate, cassava starch and corn starch.

[0090] In the present invention, the growth-promoting factor II can provide trace components required for bacterial growth; the growth-promoting factor II includes one or more of all trace metal elements and / or one or more of all vitamins.

[0091] In the present invention, the protective agent II can put the bacteria in a dormant state, maintain a certain activity of the bacteria, prevent the bacteria from dying, and prolong the stability time of the bacterial agent; preferably, the protective agent II includes glycerol and / or trehalose.

[0092] In some embodiments of the present invention, the nutrient agent II is a substance II containing CNP, which includes one or more of glucose, urea, peptone and potassium dihydrogen phosphate.

[0093] Preferably, the dosage ratio of denitrifying bacteria, biological aid II and nutrient II in the Biotra-DN composite microbial preparation is 1-5:1-5:1-5.

[0094] According to the present invention, the nutrient agent I and the nutrient agent II are the same or different; preferably, the mass ratio of carbon, nitrogen and phosphorus in the nutrient agent I and the nutrient agent II is 100:20:1.

[0095] In some specific examples of the present invention, the Biotra-DN composite microbial preparation consists of Pseudomonas, Bacillus, Fumei powder, powdered activated carbon, bamboo charcoal powder, diatomaceous earth, calcium alginate, glycerol, trehalose, glucose, urea, potassium dihydrogen phosphate, and peptone.

[0096] In some specific preferred examples of the present invention, the Biotra-DN composite microbial preparation is composed of Pseudomonas, Bacillus, Fumei powder, powdered activated carbon, bamboo charcoal powder, diatomaceous earth, calcium alginate, glycerol, trehalose, glucose, urea, potassium dihydrogen phosphate, and peptone in a ratio of 5:5:5:4:2:2:1:2:2:1:1:1:1.

[0097] In some embodiments of the present invention, the carrier added to the nitrifying composite microbial preparation includes but is not limited to biological ropes, which are composed of PET nano-modified composite fibers. Preferably, the diameter of the biological rope is 80-85 mm, and the specific surface area is greater than 0.55 m 2 / g, dry weight>50g / m, breaking strength>2800N.

[0098] In the present invention, the activated carbon carrier includes but is not limited to activated carbon and / or activated coke.

[0099] In some embodiments of the present invention, the activated carbon is coal-made granular activated carbon; preferably, the activated carbon has an iodine value of 600-1100 mg / g, a strength of >90%, and a specific surface area of ​​500-1200 m 2 / g.

[0100] In some embodiments of the present invention, the activated coke has an iodine value of 400-800 mg / g, a strength of more than 90%, and a specific surface area of ​​400-800 m 2 / g.

[0101] In the present invention, the COD in the wastewater is 7-220 mg / L, the alkalinity is 41.3-123.7, the total nitrogen is 3.6-80 mg / L, and the ammonia nitrogen is 1.43-17.3 mg / L.

[0102] In some embodiments of the present invention, the nitrogen-containing wastewater includes but is not limited to lake dredging water and / or lake demolition water, aquaculture water, etc.

[0103] It should be understood by those skilled in the art that, in the present invention, sodium acetate is a type of carbon source, is the main nutrient required for the Biotra-DN system to degrade total nitrogen during operation, and is also a necessary condition for the system to degrade total nitrogen (not unique to the system, other denitrification processes also require a carbon source); and the nutrient agent (CNP) is added as a nutrient agent when the system is started, because it needs to stand for 3 to 5 days without water intake, and the bacterial agent cannot continuously absorb nutrients. In order to allow the bacterial agent to grow and reproduce in large quantities.

[0104] III. Detection Method

[0105] 1. Ammonia nitrogen detection experiment

[0106] The required instruments mainly include: UV-visible spectrophotometer (DR3900, HACH).

[0107] The operation steps mainly include:

[0108] (1) Turn on the UV-visible spectrophotometer (DR3900, HACH) and select program 380.

[0109] (2) Take two 1-inch cuvettes that come with the Hach test instrument.

[0110] (3) Add 10 mL of the supplied deionized water (or nitrogen-free water to replace the supplied deionized water) to one of the cuvettes as a blank, and add 10 mL of the sample to the other cuvette.

[0111] (4) Add mineral stabilizer to two cuvettes respectively and shake evenly.

[0112] (5) Add polyvinyl alcohol dispersant to two cuvettes respectively and shake evenly.

[0113] (6) Add 0.4 mL of Nessler’s reagent to each of the two cuvettes and shake well.

[0114] (7) Start the instrument timer and time the reaction for 1 minute.

[0115] (8) After the timing is finished, wipe the blank cuvette clean and place it in the adapter. Press the "Zero" button to zero the instrument.

[0116] (9) Wipe the colorimetric tube containing the sample clean and place it in the adapter. Press the "Read" button to read the ammonia nitrogen content.

[0117] 2. Total nitrogen detection experiment

[0118] The required instruments mainly include: digestion reactor (DRB200, HACH), UV-visible spectrophotometer (DR3900, HACH).

[0119] The operation steps mainly include:

[0120] (1) Take a low-range total nitrogen digestion reagent tube (detection range is 0-25 mg / L) and add a pack of total nitrogen persulfate reagent powder.

[0121] (2) Add 2 mL of the supplied deionized water (or water that is completely nitrogen-free to replace the supplied deionized water) to one reagent tube as a blank, and add 2 mL of the sample to each of the remaining reagent tubes.

[0122] (3) Cover the reagent tube with a lid and shake vigorously for at least 30 seconds to mix thoroughly.

[0123] (4) Open the DRB200 digester and heat to 105°C. Insert the reagent tube into the digester, cover it, and heat and digest for 30 minutes. After the digestion time is over, immediately remove it from the digester and place it on the reagent tube cooling rack to cool to room temperature.

[0124] (5) Open the lid of the reagent tube and add one pack of TNA (total nitrogen A) reagent powder pack to each reagent tube. Close the lid and shake the reagent tube up and down for 15 seconds. Start the instrument timer and time the reaction for 3 minutes.

[0125] (6) After the timing is over, open the lid of the reagent tube and add one pack of TNB (total nitrogen B) reagent powder pack to each reagent tube. Close the lid and shake the reagent tube up and down for 15 seconds. Start the instrument timer and time the reaction for 2 minutes.

[0126] (7) After the timing is over, open the two TNC (total nitrogen C) reagent tubes and add 2 mL of digestion solution to each TNC reagent tube. Cover the lid and slowly invert the reagent tube 10 times to mix evenly. Start the instrument timer and time the reaction for 5 minutes.

[0127] (8) After the timing is over, turn on the DR3900 and select the TN LR program. Wipe the blank reagent tube clean and place it in the 16 mm circular adapter. Press the "Zero" button to zero the instrument.

[0128] (9) Wipe the reagent tube containing the sample clean and place it into the 16 mm round adapter. Press the "Read" button to read the total nitrogen content.

[0129] Example

[0130] The present invention is described in detail below through specific examples. The experimental methods described below, unless otherwise specified, are all routine laboratory methods. The experimental materials described below, unless otherwise specified, can all be obtained from commercial channels.

[0131] use Figure 1 The total nitrogen removal device for nitrogen-containing wastewater shown in the figure first mixes the nitrifying composite microbial preparation with the biological rope carrier and the nitrogen-containing wastewater raw water, aerates and cultivates, obtains the biological rope carrier with the nitrifying composite microbial film stably attached, and empties the liquid in the reaction tank I; mixes and cultivates the Biotra-DN composite microbial preparation with the activated carbon carrier and the first-level ammonia nitrogen reduction wastewater, obtains the activated carbon carrier with the Biotra-DN composite microbial film stably attached, and fully introduces the first-level ammonia nitrogen reduction wastewater into the reaction tank II of the Biotra-DN system to degrade the total nitrogen. Wastewater and a corresponding proportion of nutrient solution are introduced into the reaction tank to degrade the target pollutants and obtain dischargeable water.

[0132] Embodiment 1:

[0133] (I) Wastewater indicators

[0134] At present, reducing non-point source pollution, cutting off point source pollution, and measures such as dredging and dismantling fences have become the main means of water environment management. Generally, the sludge in the lake that has been cleared will be compressed to produce dredging water, which needs to be treated to meet the Class III water standard (TN≤1mg / L) before it can be discharged back to the original water body. The specific pollutant indicators of the dredging water of a lake are shown in Table 1 below, among which TN is mainly difficult to meet the standard and difficult to treat.

[0135] Table 1

[0136] index COD Alkalinity TN Ammonia nitrogen Nitrate pH Value (mg / L) 7 90.1 3.6 2 0.5 7.24

[0137] (II) Preparation of nitrifying composite microbial preparations and Biotra-DN composite microbial preparations

[0138] (1) Preparation of nitrifying composite microbial preparation (nitrifying bacteria, biological aid I and nutrient I):

[0139] The nitrifying bacteria are obtained by adding aerobic pool sludge taken from a biochemical pool of a sewage treatment plant in Wujin Textile Industrial Park, Changzhou City, Jiangsu Province, into water containing ammonia nitrogen, and culturing for 5 days under aeration to obtain extraction. The results of bacterial flora analysis show that they mainly include Nitrosomonas and Nitrobacter, and the ratio of Nitrosomonas to Nitrobacter is 3:5 (quantity ratio); wherein the water containing ammonia nitrogen is wastewater prepared by using river water to have an ammonia nitrogen concentration of 100 mg / L;

[0140] Biological additives I include microcarriers I, growth promoting factors I, and protective agents I;

[0141] The microcarrier I is a mixed reagent comprising talc powder, pumice powder, zeolite powder and diatomaceous earth in a mass ratio of 5:4:4:1;

[0142] Growth factor I is a mixed reagent containing trace metal elements (magnesium sulfate, ferrous sulfate, zinc chloride in a mass ratio of 1:1:1); the protective agent I is a mixed reagent containing glycerol, nitrite, and nitrate in a mass ratio of 1:2:2;

[0143] The above-mentioned nutrient agent I is a substance I containing CNP, which is a mixed reagent comprising glucose, urea, peptone and potassium dihydrogen phosphate in a mass ratio of 8:1:1:1;

[0144] The dosage ratio of nitrifying bacteria, biological additive I and nutrient agent I in the above-mentioned nitrifying composite microbial preparation is 5:4:1.

[0145] (2) Preparation of Biotra-DN composite microbial preparation (denitrifying bacteria, biological additive II and nutrient II):

[0146] The denitrifying bacteria are composed of Pseudomonas stutzeri DY-2316 (strain collection number is GCMCC No. 28879) and Bacillus licheniformis DY-2306 (strain collection number is CGMCC No. 28526). In addition, Pseudomonas stutzeri: Bacillus licheniformis = 5:5 (quantity ratio);

[0147] Biological additives II include microcarriers II, growth promoting factors II, and protective agents II;

[0148] The microcarrier II is a mixed reagent comprising beauty-enhancing powder, powdered activated carbon, bamboo charcoal powder, diatomaceous earth, and calcium alginate in a mass ratio of 5:4:2:2:1; the growth-promoting factor II is a mixed reagent comprising trace metal elements (magnesium sulfate, ferrous sulfate, and zinc chloride in a mass ratio of 1:1:1); the protective agent II is a mixed reagent comprising glycerol and trehalose in a mass ratio of 1:1;

[0149] The nutrient agent II is a substance II containing CNP, which is a mixed reagent comprising glucose, urea, peptone and potassium dihydrogen phosphate in a mass ratio of 8:1:1:1.

[0150] The dosage ratio of denitrifying bacteria, biological additive II and nutrient agent II in the above-mentioned Biotra-DN composite microbial preparation is 5:3:1.

[0151] (III) Treatment of the lake water

[0152] (1) Based on the carrier mass, 1‰ of the nitrifying composite microbial preparation is added to the reaction tank I containing the biological rope carrier, so that it is evenly distributed on the biological rope and other carriers, and nitrogen-containing wastewater is added to the reaction tank I to raise the water level to just immerse the biological rope and other carriers, thereby obtaining a composite microbial preparation-biological rope and other carriers-nitrogen-containing wastewater mixture;

[0153] (2) maintaining the water temperature between 18 and 30° C. and aerating, culturing the mixture of microbial composite culture solution-bio-rope and other carriers-nitrogen-containing wastewater for 3 to 5 days, so that the nitrifying composite microbial community is stably attached to the bio-rope and other carriers to form a biofilm, obtaining the bio-rope and other carriers with stably attached nitrifying composite microbial film, and draining the liquid in reaction tank I.

[0154] (3) directly introducing nitrogen-containing wastewater at full load into the reaction tank I of the nitrification system to degrade ammonia nitrogen, thereby obtaining first-level ammonia nitrogen-reduced wastewater with ammonia nitrogen less than 0.5 mg / L;

[0155] (4) Based on the mass of the carrier, 1% of the Biotra-DN composite microbial preparation was added to the reaction tank II containing the activated carbon carrier, so that it was evenly distributed on the activated carbon carrier, and the first-level ammonia nitrogen reduction wastewater was added to the reaction tank II, so that the water level was raised to just immerse the activated carbon carrier, and a composite microbial preparation-activated carbon carrier-first-level ammonia nitrogen reduction wastewater mixture was obtained;

[0156] (5) The mixture of composite microbial preparation-activated carbon carrier II-primary ammonia nitrogen reduction wastewater is cultured by stirring at the bottom or circulating internally, so that the Biotra-DN composite microbial community is stably attached to the activated carbon carrier to form a biofilm, and an activated carbon carrier with a stably attached Biotra-DN composite microbial film is obtained, and the liquid in the reaction tank II is drained.

[0157] (6) The primary ammonia nitrogen reduction wastewater is directly introduced into the reaction tank II of the Biotra-DN system at full load to degrade the total nitrogen and obtain dischargeable water with a total nitrogen content of <1 mg / L.

[0158] (IV) Operating parameters

[0159] The nitrification system is aerated to ensure that the dissolved oxygen is higher than 4 mg / L, and EBCT = 30 min. The Biotra-DN system uses activated carbon A as the carrier, and sodium acetate is added to provide a carbon source, and EBCT = 4 h.

[0160] (V) Operation data

[0161] Running data such as Figure 2 As shown in Table 2 below:

[0162] Table 2

[0163] Influent (mg / L) Outlet water (mg / L) Removal rate (%) TN 3.38±0.53 0.97±0.49 72.21±9.91

[0164] From the above and Figure 2As can be seen from Table 2, the raw water that needs to remove total nitrogen (including ammonia nitrogen and nitrate nitrogen) is pumped into the nitrification system by the nitrification system inlet pump. The nitrification system is filled with biological ropes inoculated with nitrifying bacteria, which can convert ammonia nitrogen into nitrate nitrogen under aerobic conditions. At present, ammonia nitrogen can be reduced to below 0.5 mg / L under sufficient alkalinity conditions. If the alkalinity in the raw water is insufficient or the pH is acidic, an alkalinity or pH monitoring device can be added for real-time regulation. Oxygen is supplied by an air pump. The water produced by the nitrification system is pumped into the reactor by the Biotra-DN system inlet pump. Carbon source needs to be added to convert nitrate nitrogen into nitrogen gas and water, thereby removing total nitrogen. This process will increase the pH, so it is necessary to control the pH of the inlet water not too high, and acid is added for adjustment when necessary. Through the combined action of the two systems, the total nitrogen in the produced water can be controlled below 1 mg / L, at least meeting the total nitrogen and ammonia nitrogen requirements of Class III water in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0165] Embodiment 2:

[0166] To illustrate the effectiveness of the present invention in more detail, a lake desilting gas floating water was selected, wherein the influent pollutant index is shown in Table 3 below. The present invention was used to operate and adjust the process parameters. Sodium acetate was added to the Biotra-DN system to provide a carbon source, EBCT = 3h, and the system was operated continuously for about 15 days. The influent and effluent TN were tested. The results are as follows: Figure 3 As shown, in the first 6 days, the system effluent was 1-1.5 mg / L, and then the system effluent TN was stable <1 mg / L. It at least meets the requirements of total nitrogen and ammonia nitrogen for Class III water in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0167] Table 3

[0168] index COD Alkalinity TN Ammonia nitrogen pH Value (mg / L) 16 105 5.6 4.1 7.85

[0169] Embodiment 3:

[0170] To illustrate the effectiveness of the present invention in more detail, a lake desilting gas floating water was selected, wherein the influent pollutant index is shown in Table 4 below. The present invention was used to operate and adjust the process parameters. Sodium acetate was added to the Biotra-DN system to provide a carbon source, and activated carbon C was used as a carrier. EBCT = 2h. After continuous operation for 2 months, the influent and effluent TN were tested. The results are shown in Table 4. Figure 4 As shown in the figure, the system effluent was 1-2 mg / L in the first 10 days, and then the TN of the system effluent fluctuated around 1 mg / L until the effluent stabilized at <1 mg / L. This at least meets the requirements for total nitrogen and ammonia nitrogen of Class III water in the Environmental Quality Standards for Surface Water (GB 3838-2002).

[0171] Table 4

[0172] index COD Alkalinity TN Ammonia nitrogen Nitrate Nitrite Value (mg / L) 27±4.08 117±7.53 4.65±1.40 2.75±1.34 0.53±0.25 0.07±0.03

[0173] Embodiment 4:

[0174] To illustrate the effectiveness of the present invention in more detail, a lake dredging sludge filter water was selected, wherein the influent pollutant index is shown in Table 5 below, and the process parameters were adjusted by the present invention, wherein the Biotra-DN system used two different activated carbon carriers in series, EBCT = 1h + 1h, and was continuously operated for 20 days, and the influent and effluent TN were tested, and the results are as follows: Figure 5 As shown, the TN of the system outlet water is stable <1mg / L. It at least meets the requirements for total nitrogen and ammonia nitrogen of Class III water in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0175] Table 5

[0176] index COD Alkalinity TN Ammonia nitrogen pH Value (mg / L) 10 46.3 7.0 6.48 8.23

[0177] Embodiment 5:

[0178] To illustrate the effectiveness of the present invention in more detail, a lake dredging sludge filter water was selected, wherein the influent pollutant index is shown in Table 6 below, and the process parameters were adjusted by the present invention, wherein the Biotra-DN system used two different activated carbon carriers in series, EBCT = 40min + 40min, and was continuously operated for one week, and the influent and effluent TN were tested, and the results are shown in FIG. Figure 6 As shown, the TN of the system outlet water is stable <1mg / L. It at least meets the requirements for total nitrogen and ammonia nitrogen of Class III water in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0179] Table 6

[0180] index COD Alkalinity TN Ammonia nitrogen pH Value (mg / L) 10±0 41.3±7.07 11.05±5.73 10.24±5.32 7.85±0.54

[0181] Embodiment 6:

[0182] To illustrate the effectiveness of the present invention in more detail, a lake dredging sludge filter water was selected, wherein the influent pollutant index is shown in Table 7 below, and the process parameters were adjusted by the present invention, wherein the Biotra-DN system used a two-stage series connection EBCT = 30min + 30min, and was continuously operated for 56 days, and the influent and effluent TN were tested, and the results are as follows: Figure 7 As shown, the TN of the system outlet water is stable <1mg / L. It at least meets the requirements for total nitrogen and ammonia nitrogen of Class III water in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0183] Table 7

[0184] index COD Alkalinity TN Ammonia nitrogen pH Value (mg / L) 17.67±5.13 60.0±15.8 14.13±4.37 13.25±4.18 7.70±0.62

[0185] Embodiment 7:

[0186] To illustrate the effectiveness of the present invention in more detail, a certain aquaculture wastewater was selected, wherein the influent pollutant index is shown in Table 8 below, and the effluent TN is required to be <5 mg / L. The present invention was used to operate and adjust the process parameters, wherein the nitrification system EBCT = 4h, the denitrification system EBCT = 6h, and the Biotra-DN system EBCT = 30min. The influent and effluent TN were tested, and the results are as follows: Figure 8 As shown in the figure, the final effluent TN of the system is less than 1mg / L, which meets the effluent requirements.

[0187] Table 8

[0188] index COD TN Ammonia nitrogen Nitrate pH TP Value (mg / L) 220 80 4.65 56 7.49 16

[0189] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A method for reducing total nitrogen in nitrogen-containing wastewater to an ultra-low concentration, comprising: Step A, in a reaction tank I of a nitrification system, a nitrifying composite microbial preparation is mixed and cultured with a carrier I and nitrogen-containing wastewater to obtain a carrier I with a nitrifying composite microbial membrane stably attached thereto; Step B, directly introducing nitrogen-containing wastewater at full load into the reaction tank I of the nitrification system to degrade ammonia nitrogen, thereby obtaining primary ammonia nitrogen-reduced wastewater; Step C, in the reaction tank II of the Biotra-DN system, the Biotra-DN composite microbial preparation is mixed and cultured with the carrier II and the primary ammonia nitrogen reduction wastewater to obtain the carrier II with the Biotra-DN composite biofilm stably attached; Step D, directly introducing the primary ammonia nitrogen reduction wastewater into the reaction tank II of the Biotra-DN system at full load to degrade the total nitrogen to obtain dischargeable water; Among them, the ammonia nitrogen of the first-level ammonia nitrogen reduction wastewater is less than 0.5 mg / L; the total nitrogen of the dischargeable water is less than 1 mg / L.

2. The method according to claim 1, characterized in that: Step A includes: Step S1, adding the nitrifying composite microorganism preparation into a reaction tank I containing a carrier I, so that the preparation is evenly distributed on the carrier I, and adding nitrogen-containing wastewater into the reaction tank I, so that the water level rises to just immerse the carrier I, to obtain a mixture of the nitrifying composite microorganism preparation-carrier I-nitrogen-containing wastewater; Step S2, aeration, culturing the mixture of nitrifying composite microorganism preparation-carrier I-nitrogen-containing wastewater, allowing the nitrifying composite microorganism group to stably attach to carrier I to form a biofilm, obtaining carrier I with a stably attached nitrifying composite microbial film, and draining the liquid in reaction tank I.

3. The method according to claim 1, characterized in that Step C includes: Step T1, adding the Biotra-DN composite microbial preparation to the reaction tank II containing the carrier II, so that it is evenly distributed on the carrier II, and adding the primary ammonia nitrogen reduction wastewater to the reaction tank II, so that the water level rises to just immerse the carrier II, and obtains a mixture of Biotra-DN composite microbial preparation-carrier II-primary ammonia nitrogen reduction wastewater; Step T2, bottom stirring or internal circulation, culturing the Biotra-DN composite microbial preparation-carrier II-primary ammonia nitrogen reduction wastewater mixture, allowing the Biotra-DN composite microbial community to stably attach to carrier II to form a biofilm, obtaining carrier II with stably attached Biotra-DN composite microbial film, and draining the liquid in reaction tank II.

4. The method according to claim 2 or 3, characterized in that: In steps S2 and T2, the water temperature is maintained between 18 and 30°C; preferably, the culturing time is 3 to 5 days.

5. The method according to any one of claims 1 to 4, characterized in that: The nitrifying composite microbial preparation comprises nitrifying bacteria, biological aid I and nutrient agent I; Preferably, the nitrifying bacteria include Nitrosomonas and / or Nitrobacter; And / or, the biological additive I includes microcarrier I, growth promoting factor I, and protective agent I; further preferably, the microcarrier I includes one or more of talcum powder, pumice powder, zeolite powder, powdered activated carbon, bamboo charcoal powder, white carbon black, diatomaceous earth, polycaprolactone and calcium alginate; and / or, the growth promoting factor I includes trace metal elements and / or vitamins; and / or, the protective agent I includes one or more of glycerol, trehalose, nitrite and nitrate; And / or, the nutrient agent I is a substance I containing CNP, which includes one or more of glucose, urea, peptone and potassium dihydrogen phosphate; More preferably, the dosage ratio of nitrifying bacteria, biological aid I and nutrient agent I in the nitrifying composite microbial preparation is 1-5:1-5:1-5.

6. The method according to any one of claims 1 to 4, characterized in that: The Biotra-DN composite microbial preparation includes denitrifying bacteria, biological additive II and nutrient II; Preferably, the denitrifying bacteria include Pseudomonas and / or Bacillus; And / or, the biological additive II includes microcarrier II, growth factor II, and protective agent II; further preferably, the microcarrier II includes one or more of auxiliary beauty powder, powdered activated carbon, bamboo charcoal powder, white carbon black, diatomaceous earth, polycaprolactone, calcium alginate, cassava starch and corn starch; and / or, the growth factor II includes trace metal elements and / or vitamins; and / or, the protective agent II includes glycerol and / or trehalose; And / or, the nutrient II is a substance II containing CNP, which includes one or more of glucose, urea, peptone and potassium dihydrogen phosphate; More preferably, the dosage ratio of denitrifying bacteria, biological additive II and nutrient agent II in the Biotra-DN composite microbial preparation is 1-5:1-5:1-5.

7. The method according to claim 5 or 6, characterized in that: The nutrient agent I and the nutrient agent II are the same or different; preferably, the mass ratio of carbon, nitrogen and phosphorus in the nutrient agent I and the nutrient agent II is 100:5:

1.

8. The method according to any one of claims 1 to 7, characterized in that: The carrier I comprises a biological rope; preferably, the biological rope is composed of PET nano-modified composite fibers, and more preferably, the diameter of the biological rope is 80-85 mm, and the specific surface area is greater than 0.55 m 2 / g, dry weight>50g / m, breaking strength>2800N.

9. The method according to any one of claims 1 to 7, characterized in that: The carrier II comprises activated carbon and / or activated coke; preferably, the activated carbon is coal-made granular activated carbon; more preferably, the activated carbon has an iodine value of 600 to 1100 mg / g, a strength of >90%, and a specific surface area of ​​500 to 1200 m 2 / g; and / or, preferably, the activated coke has an iodine value of 400-800 mg / g, a strength of >90%, and a specific surface area of ​​400-800 m 2 / g.

10. The method according to any one of claims 1 to 9, characterized in that: The nitrogen-containing wastewater includes one or more of lake desilting water, lake demolition water, aquaculture wastewater, industrial wastewater, municipal wastewater and river water.

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