Integrated micro-nano aeration gradient biofilm reaction system

Abstract

The utility model relates to the technical field of sewage and wastewater treatment, in particular to an integrated micro-nano aeration gradient biological membrane reaction system. The system comprises a water inlet pump, a micro-nano aeration unit, a sewage storage tank, an overflow port and a gradient biological membrane reaction unit, the water inlet pump, the micro-nano aeration unit and the sewage storage tank are sequentially connected, and the overflow port is formed between the sewage storage tank and the gradient biological membrane reaction unit; the gradient biological membrane reaction unit comprises a rough filtration adsorption layer, a nitration reaction layer and a denitrification nitrogen removal layer which are arranged from top to bottom. On the basis of sewage aerated by the micro-nano aeration unit, stage treatment of the sewage is realized, so that the sewage can be well degraded, and the sewage treatment effect is improved. Meanwhile, the system is simple in structure and low in cost, and solves the problems of high cost and high system operation energy consumption in the prior art.

Description

TECHNICAL FIELD

[0001] The utility model relates to sewage wastewater treatment technical field especially relates to a integrated micro - nanometer aeration gradient biological membrane reaction system. BACKGROUND

[0002] The efficient treatment of black and odorous water and ammonia-nitrogen-containing wastewater is a core challenge in the field of environmental engineering. Black and odorous water is mainly caused by the anaerobic decomposition of organic matter to produce hydrogen sulfide, ammonia and other foul-smelling substances, accompanied by problems such as oxygen deficiency and sediment accumulation. Ammonia-nitrogen-containing wastewater is widely derived from industries such as chemical industry, pharmaceutical industry and landfill leachate, and its high ammonia-nitrogen concentration (usually > 50 mg / L) has a significant inhibitory effect on microbial activity. Traditional biological treatment technologies (such as activated sludge method and biological filter) have low oxygen mass transfer efficiency, insufficient degradation capacity and high energy consumption. SUMMARY

[0003] The utility model provides a integrated micro - nanometer aeration gradient biological membrane reaction system to solve one or more technical problems existing in the prior art, at least provide a beneficial choice or create conditions.

[0004] Other characteristics and advantages of the utility model will become apparent from the following detailed description, or will be learned partly by the practice of the utility model.

[0005] According to an aspect of the embodiment of the utility model, an integrated micro - nanometer aeration gradient biological membrane reaction system is provided, the system includes water inlet pump, micro - nanometer aeration unit, sewage storage box, overflow and gradient biological membrane reaction unit;

[0006] The water inlet pump, the micro - nanometer aeration unit, the sewage storage box are connected in proper order,

[0007] The overflow is located between the sewage storage box and the gradient biological membrane reaction unit, and the sewage storage box and the gradient biological membrane reaction unit are communicated through the overflow;

[0008] The gradient biological membrane reaction unit includes coarse filter adsorption layer, nitrification reaction layer and denitrification layer from top to bottom;

[0009] The water inlet pump is used to send sewage into the micro - nanometer aeration unit, and the micro - nanometer aeration unit is used to carry out aeration treatment to the sewage and send the sewage after aeration treatment into the sewage storage box;

[0010] The sewage after aeration treatment flows into the gradient biological membrane reaction unit through the overflow and is filtered and decomposed in turn through the coarse filter adsorption layer, the nitrification reaction layer and the denitrification layer to carry out graded treatment to the sewage after aeration treatment.

[0011] In one embodiment of the utility model, based on aforementioned scheme, the micro-nano aeration unit includes whirl cut type venturi and micro-nano aeration pump, whirl cut type venturi is located between water inlet pump with sewage storage tank, micro-nano aeration pump is connected with whirl cut type venturi, be used for producing the bubble of 50 nanometer ~ 200 nanometer diameter in the sewage.

[0012] In one embodiment of the utility model, based on aforementioned scheme, the sewage storage tank with gradient biological membrane reaction unit between be provided with baffle, overflow port is located in the baffle, to make the sewage from overflow port flow into gradient biological membrane reaction unit.

[0013] In one embodiment of the utility model, based on aforementioned scheme, the installation mode of coarse filter adsorption layer in gradient biological membrane reaction unit is horizontal paving, the coarse filter adsorption layer has a plurality of first through holes, the aperture of first through hole is 5 nanometer ~ 10 nanometer, the sewage from overflow port flows into nitrification reaction layer through first through hole, the surface of coarse filter adsorption layer is attached with iron-based catalyst, and the material of coarse filter adsorption layer is modified polyethylene foam.

[0014] In one embodiment of the utility model, based on aforementioned scheme, the installation mode of nitrification reaction layer in gradient biological membrane reaction unit is horizontal paving, the nitrification reaction layer has a plurality of second through holes, the aperture of second through hole is 2 nanometer ~ 5 nanometer, liquid from first through hole flows into denitrification layer through second through hole, the material of nitrification reaction layer is polyurethane porous elastic filler, calcium carbonate particles are pre-buried in the nitrification reaction layer, so that the pH value of nitrification reaction layer is in the range of 7.0 ~ 8.5.

[0015] In one embodiment of the utility model, based on aforementioned scheme, the installation mode of denitrification layer in gradient biological membrane reaction unit is inclined paving, the denitrification layer has a plurality of third through holes, the aperture of third through hole is 0.5 nanometer ~ 2 nanometer, liquid from second through hole is discharged from third through hole, the material of denitrification layer is pyrite-zeolite composite filter material, and the surface of denitrification layer is covered with sulfur / limestone composite slow-release layer.

[0016] In one embodiment of the utility model, based on aforementioned scheme, the system further includes water outlet, and the water outlet is arranged at the bottom of the gradient biological membrane reaction unit, and the liquid discharged from the third through hole is discharged through the water outlet.

[0017] In an embodiment of the utility model, based on preceding scheme, the system still includes backwash water inlet and backwash water outlet, backwash water inlet and backwash water outlet all are located in the lateral wall of gradient biological membrane reaction unit, backwash water inlet is located below denitrification layer, backwash water outlet is located above rough filtration adsorption layer and below overflow port,

[0018] Wherein, backwash water inlet and backwash water outlet are on the same side, backwash water outlet and overflow port are located on both sides of gradient biological membrane reaction unit respectively.

[0019] The utility model discloses the beneficial effect is: through water inlet pump, sewage is introduced into micro -nano aeration unit and is carried out aeration treatment, through micro -nano level aeration treatment, can cut the mode of high -speed gyration and dissolve into sewage in air, produce nanometer level bubble in sewage, thereby air is dissolved into water fast and efficiently, can improve the dissolution efficiency of air, meet the requirement of sewage treatment.

[0020] Further, overflow port is arranged between sewage storage box and gradient biological membrane reaction unit, so that the sewage after aeration treatment of micro -nano aeration unit can only flow into gradient biological membrane reaction unit from overflow port, and then the sewage can be sequentially treated by the rough filtration adsorption layer, nitrification reaction layer and denitrification layer, so that the sewage is filtered and decomposed layer by layer, and finally the degradation treatment of the sewage is completed.

[0021] Compared with the traditional technology, the traditional technology usually only designs a single carrier or a single filter degradation layer to treat sewage, and the problem caused by the single function of the filter material of the traditional technology is low oxygen mass transfer efficiency and insufficient degradation capacity. The traditional technology can also further treat sewage by combining a single carrier or a single filter degradation layer with other auxiliary equipment with high cost, but this way will cause high cost and high energy consumption.

[0022] Therefore, the integrated micro -nano aeration gradient biological membrane reaction system of the utility model realizes the hierarchical treatment of sewage on the basis of the sewage treated by the micro -nano aeration unit, so that the sewage can be well degraded and the treatment effect of the sewage is improved. At the same time, the system structure of the utility model is simple and the cost is low, which solves the problems of high cost and high system operation energy consumption in the traditional technology. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly describe the drawings needed in the embodiment description. Obviously, the described drawings are only part of the embodiments of the present application, not all embodiments, and the person skilled in the art can obtain other design schemes and drawings according to these drawings without creative labor.

[0024] Figure 1 The overall logic block diagram of the integrated micro-nano aeration gradient biological membrane reaction system according to the embodiment of the present application is shown.

[0025] Figure 2 The specific structure diagram of the integrated micro-nano aeration gradient biological membrane reaction system according to the embodiment of the present application is shown.

[0026] Figure 3 The top view of the integrated micro-nano aeration gradient biological membrane reaction system according to the embodiment of the present application is shown.

[0027] Reference signs

[0028] Controller 1, micro-nano aeration unit 2, sewage storage tank 3, gradient biological membrane reaction unit 4, water inlet pump 5, aeration pump 6, backwashing water outlet 7, backwashing water inlet 8, water outlet 9, coarse filtration and adsorption layer 10, nitrification reaction layer 11, denitrification layer 12, overflow outlet 13. DETAILED DESCRIPTION

[0029] Example implementations are now described with reference to the drawings. However, example implementations can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example implementations to those skilled in the art.

[0030] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the present application. One skilled in the relevant art will recognize, however, that the technology can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail in order to avoid obscuring aspects of the present application.

[0031] The block diagrams shown in the drawings are merely functional entities, and do not necessarily correspond to physically independent entities. These functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller nodes.

[0032] The flowcharts shown in the drawings are merely exemplary illustrations, and do not necessarily include all contents and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be further decomposed, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to actual conditions.

[0033] It should be noted that "multiple" referred to herein means two or more. The association relationship of "and / or" describes the associated objects, which means that there can be three relationships, for example, A and / or B can represent the three cases of A alone, A and B together, and B alone. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0034] The background art of the present application is described in detail as follows:

[0035] Efficient treatment of black and odorous water bodies and ammonia-nitrogen-containing wastewater is a core challenge in the field of environmental engineering. Black and odorous water bodies are mainly caused by the anaerobic decomposition of organic matter to produce hydrogen sulfide, ammonia and other foul-smelling substances, accompanied by problems such as oxygen deficiency and sediment accumulation. Ammonia-nitrogen-containing wastewater is widely derived from industries such as chemical industry, pharmaceutical industry and landfill leachate, and its high ammonia-nitrogen concentration (usually > 50 mg / L) has a significant inhibitory effect on microbial activity. Traditional biological treatment technologies (such as activated sludge method and biological filter) have the bottlenecks of low oxygen mass transfer efficiency, insufficient nitrogen removal capacity and high energy consumption.

[0036] Among the current mainstream technologies, the Biological Aerated Filter (BAF) is widely used because it integrates biological degradation and filtration functions. However, traditional BAF has the following limitations:

[0037] (1) Poor aeration uniformity: single-point aeration is prone to form local over-oxygenation or dead zones, resulting in an oxygen utilization rate of less than 30%.

[0038] (2) Single function of filter material: homogeneous filter material (such as ceramic granules) cannot achieve the staged removal of COD, ammonia-nitrogen and total nitrogen, and the nitrogen removal efficiency is usually less than 70%.

[0039] (3) Manual backwashing: frequent shutdown and washing are required after filter material clogging, which has low automation and high maintenance cost.

[0040] Drawbacks of prior art

[0041] (1) Aeration system defects:

[0042] Traditional aeration bubble is large (millimeter level), oxygen dissolution rate is only 20%-30%, and energy consumption is high (≥0.5 kW·h / m³).

[0043] Traditional aeration pipe is easy to be blocked by biofilm or suspended matter, and the maintenance period is short (usually <3 months).

[0044] (2) Low biological treatment efficiency:

[0045] Single biological carrier cannot degrade COD, ammonia nitrogen and total nitrogen in stages, resulting in insufficient denitrification efficiency (total nitrogen removal rate <70%).

[0046] High ammonia nitrogen wastewater inhibits the activity of nitrifying bacteria, and additional carbon source (such as methanol) needs to be added, increasing the operation cost.

[0047] The purpose of the integrated micro-nano aeration gradient biofilm reaction system is achieved:

[0048] (1) Improve oxygen mass transfer efficiency: by combining the gradient biofilm reaction unit and the micro-nano aeration unit, the oxygen transfer efficiency is increased to ≥85%, and the energy consumption is reduced by 40%.

[0049] (2) Realize the staged treatment of pollutants: through the design of layered carriers (i.e. the coarse filtration and adsorption layer, the nitrification reaction layer and the denitrification and nitrogen removal layer for staged treatment), COD (chemical oxygen demand), ammonia nitrogen and total nitrogen are degraded in a targeted manner, and the total nitrogen removal rate is ≥90%.

[0050] (3) Reduce the dependence on carbon source: the release of endogenous electron donor (Fe²⁺) by pyrite-zeolite composite filter material reduces the carbon source addition amount by more than 50%.

[0051] The implementation details of the technical scheme of the embodiment of the utility model are described in detail as follows:

[0052] According to an aspect of the embodiment of the utility model, an integrated micro-nano aeration gradient biofilm reaction system is provided, which comprises a water inlet pump, a micro-nano aeration unit, a sewage storage tank, a water overflow port and a gradient biofilm reaction unit, as shown in Figure 1 、 Figure 2 and Figure 3 , Figure 1 is the overall logic diagram of the integrated micro-nano aeration gradient biofilm reaction system, Figure 2 is the specific structure diagram of the integrated micro-nano aeration gradient biofilm reaction system, Figure 3 is the top view of the integrated micro-nano aeration gradient biofilm reaction system. It should be noted that the aeration pump and the water inlet pump of the utility model are adjusted by the controller.

[0053] The integrated micro-nano aeration gradient biological membrane reaction system comprises a water inlet pump, a micro-nano aeration unit, a sewage storage tank, a sewage overflow port and a gradient biological membrane reaction unit.

[0054] The water inlet pump, the micro-nano aeration unit and the sewage storage tank are sequentially connected,

[0055] The sewage overflow port is arranged between the sewage storage tank and the gradient biological membrane reaction unit, and the sewage storage tank and the gradient biological membrane reaction unit are communicated through the sewage overflow port.

[0056] The gradient biological membrane reaction unit comprises a coarse filtration and adsorption layer, a nitrification reaction layer and a denitrification layer arranged from top to bottom.

[0057] The water inlet pump is used for feeding sewage into the micro-nano aeration unit, and the micro-nano aeration unit is used for performing aeration treatment on the sewage and feeding the aeration-treated sewage into the sewage storage tank.

[0058] The aeration-treated sewage flows into the gradient biological membrane reaction unit through the sewage overflow port and is sequentially subjected to filtration and decomposition treatment of the coarse filtration and adsorption layer, the nitrification reaction layer and the denitrification layer, so as to perform a hierarchical treatment on the aeration-treated sewage.

[0059] Specifically, the sewage is first pretreated by the micro-nano aeration unit, that is, air is dissolved into the sewage by means of high-speed rotary cutting, so as to generate nanoscale bubbles in the sewage, thereby quickly and efficiently dissolving air into water, improving the air dissolution efficiency and meeting the preliminary requirements for sewage treatment.

[0060] On the basis of the aeration treatment, the sewage flows into the gradient biological membrane reaction unit from the sewage overflow port, and then the sewage can be sequentially subjected to hierarchical treatment of the coarse filtration and adsorption layer, the nitrification reaction layer and the denitrification layer, so that the sewage is subjected to layer-by-layer filtration and decomposition and finally completes the degradation treatment of the sewage.

[0061] The integrated micro-nano aeration gradient biological membrane reaction system of the utility model realizes hierarchical treatment of the sewage on the basis of the aeration treatment of the sewage by the micro-nano aeration unit through the gradient biological membrane reaction unit with multiple filter materials and degradation functions, so that the sewage can be well degraded and the treatment effect of the sewage is improved.

[0062] Furthermore, the micro-nano aeration unit includes a rotary venturi tube and a micro-nano aeration pump. The rotary venturi tube is located between the influent pump and the wastewater storage tank. The micro-nano aeration pump is connected to the rotary venturi tube to generate bubbles with a diameter of 50 nanometers to 200 nanometers in the wastewater.

[0063] Specifically, the micro-nano aeration unit adopts a rotary-cut venturi tube structure, which mixes high-speed sewage flow (flow velocity 8-12 m / s) with air to generate bubbles with a diameter of 50 nm-200 nm. This results in an oxygen transfer efficiency (OTE) ≥85% and a bubble residence time in sewage ≥120 seconds (compared to only 20-30 seconds for bubbles generated by traditional aeration). The energy consumption of the micro-nano aeration unit is 0.28-0.35 kW·h / m³, which is 40% lower than that of traditional blower aeration.

[0064] Furthermore, a baffle is provided between the wastewater storage tank and the gradient biofilm reaction unit, and the overflow outlet is located in the baffle so that the wastewater flows into the gradient biofilm reaction unit from the overflow outlet.

[0065] Specifically, such as Figure 2 As shown, Figure 2 The overflow outlet is located above the baffle. In this way, the wastewater treated by aeration can accumulate and rise in the wastewater storage tank. When the liquid level exceeds the overflow outlet, the wastewater will flow from the overflow outlet into the gradient biofilm reaction unit, so that the wastewater can pass through the coarse filtration adsorption layer, the nitrification reaction layer and the denitrification denitrification layer from top to bottom to achieve step-by-step stratified degradation.

[0066] Furthermore, the coarse filtration adsorption layer is installed horizontally in the gradient biofilm reaction unit. The coarse filtration adsorption layer has multiple first through holes with a pore size of 5 nm to 10 nm. The wastewater flowing out from the overflow outlet flows into the nitrification reaction layer through the first through holes. The surface of the coarse filtration adsorption layer is coated with an iron-based catalyst, and the material of the coarse filtration adsorption layer is modified polyethylene foam.

[0067] Specifically, the gradient biofilm reaction unit is divided into three layers, each using a biological carrier with different pore sizes and materials. The three biological carriers (i.e., the coarse filtration adsorption layer, the nitrification reaction layer, and the denitrification denitrification layer) target large particulate organic matter, ammonia nitrogen oxidation, and denitrification denitrification, respectively, to achieve stepwise degradation.

[0068] The specific parameters are as follows:

[0069] (1) Coarse filtration adsorption layer (upper layer):

[0070] Material: modified polyethylene (PE) foam, pore size 5nm~10 mm, porosity ≥85%, thickness 500 mm.

[0071] Function of coarse filtration and adsorption layer: intercept large particle suspended solids (SS) and part of COD, and preliminarily reduce pollutant load through physical adsorption and facultative microbial degradation.

[0072] Installation method: horizontal paving, thickness 30 cm, carrier surface loaded with iron-based catalyst (FeOOH) to enhance the oxidation capacity of sulfides.

[0073] Further, the installation method of the nitrification reaction layer in the gradient biofilm reaction unit is horizontal paving, the nitrification reaction layer has a plurality of second through holes with a pore size of 2nm~5nm, and the liquid flowing out of the first through holes flows into the denitrification layer through the second through holes; the material of the nitrification reaction layer is polyurethane porous elastic filler, and calcium carbonate particles are pre-embedded in the nitrification reaction layer to maintain the pH value of the nitrification reaction layer in the range of 7.0~8.5.

[0074] Specifically, the nitrification reaction layer (in the middle layer):

[0075] Material: polyurethane (PU) porous elastic filler, pore size 2nm~5 mm, specific surface area 1200 m² / m³, thickness 600 mm.

[0076] Function: enrich nitrifying bacteria (such as nitrosomonas and nitrosospira), and convert ammonia nitrogen into nitrite / nitrate through aeration oxygen supply.

[0077] Installation method: horizontal paving, filling rate 70%, pre-embedded pH buffer particles (CaCO3) in the carrier to maintain the pH of the layer in the range of 7.0~8.5.

[0078] Further, the installation method of the denitrification layer in the gradient biofilm reaction unit is inclined paving, the denitrification layer has a plurality of third through holes with a pore size of 0.5nm~2nm, and the liquid flowing out of the second through holes is discharged from the third through holes; the material of the denitrification layer is pyrite-zeolite composite filter material, and the surface of the denitrification layer is covered with a sulfur / limestone composite slow-release layer.

[0079] Specifically, the denitrification layer (in the lower layer):

[0080] Material: pyrite-zeolite composite filter material, pore size 0.5nm~2 mm, specific surface area 1500 m² / m³, thickness 800 mm.

[0081] Function: Enrichment of denitrifying bacteria (such as Pseudomonas, Thiobacillus denitrificans), use of pyrite to release electron donors (Fe2 + ) and organic matter in water for denitrification.

[0082] Installation method: arranged at an angle of 15°, filling rate 60%, carrier surface coated with sulfur / limestone composite slow-release layer, providing the required electron donor for denitrification.

[0083] Further, as shown in Figure 3 , Figure 3 is a top view of the system, the system further comprises a water distributor, which adopts a perforated pipe water distribution method, the pipe diameter of the water distributor connected pipe is 10 mm, and the spacing is 200 mm, which ensures that the water flow passes through each layer of biological carrier (i.e. each layer of gradient biological membrane reaction unit) uniformly.

[0084] Further, the system further comprises a water outlet, the water outlet is arranged at the bottom of the gradient biological membrane reaction unit, and the liquid flowing out of the third through hole is discharged through the water outlet.

[0085] Specifically, the liquid flowing out of the third through hole is the liquid after the staged degradation of the sewage, at this time the liquid is discharged through the water outlet arranged below.

[0086] Further, the system further comprises a backwashing inlet and a backwashing outlet, the backwashing inlet and the backwashing outlet are both arranged on the side wall of the gradient biological membrane reaction unit; the backwashing inlet is located below the denitrification layer, and the backwashing outlet is located above the coarse filtration and adsorption layer and below the overflow outlet.

[0087] Among them, the backwashing inlet and the backwashing outlet are on the same side, and the backwashing outlet and the overflow outlet are respectively arranged on both sides of the gradient biological membrane reaction unit.

[0088] Specifically, as shown in Figure 2 , the backwashing inlet can introduce clean water with strong pressure, at this time the introduced clean water can pass through the denitrification layer, the nitrification reaction layer and the coarse filtration and adsorption layer in turn from bottom to top, so as to realize the effect of backwashing, that is, by means of backwashing, high-pressure water flow (pressure 0.2 MPa, lasting for 5 minutes) is injected in reverse to flush the pipeline and each layer of biological carrier. In this way, when the sewage is degraded or filtered, some decomposed substances will adhere to each layer of biological carrier and cause blockage, so a water flow opposite to the filtering direction is needed to clean the filter layer, and the conventional filtering process is operated alternately, so as to prevent the internal blockage of the gradient biological membrane reaction unit.

[0089] In summary, the gradient biofilm reaction unit can realize targeted degradation of pollutants, and the micro-nano aeration unit can prolong the service life of the whole system.

[0090] The gradient biofilm reaction unit and the micro-nano aeration unit are used to process and clean the black and odorous water body and ammonia-nitrogen-containing wastewater, and the problems of high energy consumption, low nitrogen removal efficiency and frequent maintenance are solved.

[0091] Therefore, the integrated micro-nano aeration gradient biofilm reaction system has the advantages of simple structure, low cost, and solves the problems of high cost and high energy consumption of the traditional technology.

[0092] In addition, the above-mentioned figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, and are not for limiting purposes. It is easy to understand that the processes shown in the above-mentioned figures do not indicate or limit the time sequence of the processes. In addition, it is also easy to understand that the processes can be executed synchronously or asynchronously in multiple modules.

[0093] It should be understood that the present application is not limited to the precise construction which has been described above and illustrated in the accompanying drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the claims that follow.

Claims

1. An integrated micro-nano aeration gradient biofilm reactor system, characterized in that, The system comprises a water inlet pump, a micro-nano aeration unit, a sewage storage tank, a water overflow port and a gradient biological membrane reaction unit. The water inlet pump, the micro-nano aeration unit and the sewage storage tank are connected in sequence, The water overflow port is arranged between the sewage storage tank and the gradient biological membrane reaction unit, and the sewage storage tank and the gradient biological membrane reaction unit are communicated through the water overflow port. The gradient biological membrane reaction unit comprises a coarse filtration and adsorption layer, a nitrification reaction layer and a denitrification and nitrogen removal layer arranged from top to bottom. The water inlet pump is used to send sewage into the micro-nano aeration unit, and the micro-nano aeration unit is used to perform aeration treatment on the sewage and send the aeration-treated sewage into the sewage storage tank. The aeration-treated sewage flows into the gradient biological membrane reaction unit through the water overflow port and is subjected to filtration and decomposition treatment in sequence through the coarse filtration and adsorption layer, the nitrification reaction layer and the denitrification and nitrogen removal layer, so as to perform a hierarchical treatment on the aeration-treated sewage.

2. The integrated micro-nano aeration gradient biofilm reactor system of claim 1, wherein, The micro-nano aeration unit comprises a rotary cutting type Venturi tube and a micro-nano aeration pump, the rotary cutting type Venturi tube is arranged between the water inlet pump and the sewage storage tank, and the micro-nano aeration pump is connected with the rotary cutting type Venturi tube to generate bubbles with a diameter of 50-200 nanometers in the sewage.

3. The integrated micro-nano bubble aeration gradient biofilm reactor system of claim 1, wherein, A baffle is arranged between the sewage storage tank and the gradient biological membrane reaction unit, and the water overflow port is arranged in the baffle, so that the sewage flows into the gradient biological membrane reaction unit from the water overflow port.

4. The integrated micro-nano bubble aeration gradient biofilm reactor system of claim 1, wherein, The coarse filtration and adsorption layer is horizontally laid in the gradient biological membrane reaction unit, has a plurality of first through holes with a pore diameter of 5-10 nanometers, and the sewage flowing out of the water overflow port flows into the nitrification reaction layer through the first through holes; the surface of the coarse filtration and adsorption layer is attached with an iron-based catalyst, and the material of the coarse filtration and adsorption layer is modified polyethylene foam.

5. The integrated micro-nano diffused aeration gradient biofilm reactor system of claim 4, wherein, The nitrification reaction layer is horizontally laid in the gradient biological membrane reaction unit, has a plurality of second through holes with a pore diameter of 2-5 nanometers, and the liquid flowing out of the first through holes flows into the denitrification and nitrogen removal layer through the second through holes; the material of the nitrification reaction layer is polyurethane porous elastic filler, and calcium carbonate particles are pre-embedded in the nitrification reaction layer to make the pH value of the nitrification reaction layer in the range of 7.0-8.

5.

6. The integrated micro-nano diffused aeration gradient biofilm reactor system of claim 5, wherein, The denitrification and nitrogen removal layer is obliquely laid in the gradient biological membrane reaction unit, has a plurality of third through holes with a pore diameter of 0.5-2 nanometers, and the liquid flowing out of the second through holes is discharged from the third through holes; the material of the denitrification and nitrogen removal layer is pyrite-zeolite composite filter material, and the surface of the denitrification and nitrogen removal layer is covered with a sulfur / limestone composite slow-release layer.

7. The integrated micro-nano diffused aeration gradient biofilm reactor system of claim 6, wherein, The system further comprises a water outlet arranged at the bottom of the gradient biological membrane reaction unit, and the liquid flowing out of the third through holes is discharged through the water outlet.

8. The integrated micro-nano diffused aeration gradient biofilm reactor system of claim 1, wherein, The system further comprises a backwash inlet and a backwash outlet, both of which are arranged on the side wall of the gradient biological membrane reaction unit; the backwash inlet is located below the denitrification layer, and the backwash outlet is located above the coarse filtration and adsorption layer and below the overflow outlet. The backwash inlet and the backwash outlet are on the same side, and the backwash outlet and the overflow outlet are arranged on the two sides of the gradient biological membrane reaction unit, respectively.

Images