An air self-diffusion microbial membrane for sewage treatment and its preparation method and application

Abstract

The present invention relates to an air self-diffusion microbial membrane for sewage treatment and a preparation method and application thereof, and belongs to the technical field of biofilm preparation. The air self-diffusion microbial membrane disclosed by the present invention includes a hydrophobic layer, an adhesive layer, a hydrophilic layer and a microbial layer from the outside to the inside, wherein the adhesive layer has the functions of supporting, connecting the waterproof layer and the hydrophilic layer, waterproofing and air permeability, and the air diffusion flux size is regulated by adjusting the thickness of the adhesive layer. The present invention realizes the diffusion of air from the hydrophobic layer side to the hydrophilic layer side by constructing an air self-diffusion microbial membrane, replacing the traditional aeration or mechanical aeration oxygen supply method; at the same time, the present invention enhances its hydrophilicity and microbial biofilm performance by modifying the hydrophilic layer material, thereby improving the loading capacity of microorganisms. The air self-diffusion microbial membrane disclosed by the present invention has low preparation cost, and the process is simple to construct when used for sewage treatment, and does not require aeration, secondary sedimentation tanks and geotechnical construction, etc., which can reduce the investment cost and operation cost of sewage treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of biofilm preparation, and relates to an air self-diffusion microbial film for sewage treatment and a preparation method and application thereof. Background Art

[0002] Aeration and sludge-water separation are the two core elements of sewage treatment technology. Traditional activated sludge processes rely on forced aeration or mechanical aeration to provide oxygen for microorganisms. This method consumes extremely high energy, and aeration energy consumption accounts for 50% to 70% of the total energy consumption of sewage treatment plants. High energy consumption not only leads to increased operating costs, but also puts pressure on achieving low-carbon environmental protection. In order to achieve the separation of sludge and water, traditional activated sludge processes must be equipped with large sedimentation tanks and reaction tanks, which occupy nearly half of the land resources of sewage treatment plants, significantly increasing investment and construction costs; at the same time, sludge return is required, which consumes energy and cannot enrich functional microorganisms, reducing treatment efficiency. Especially in urban sewage treatment, land resources are tight, and this large-scale process significantly increases infrastructure and operating costs.

[0003] Although the biofilm process has improved the separation of sludge and water, and has effectively reduced the need for sedimentation tanks through membrane filtration, aeration is still its key link. The aeration process consumes huge amounts of energy, and the efficiency of bubble dissolved oxygen is low, which affects the sufficient oxygen supply to microorganisms and reduces the efficiency of sewage treatment. At the same time, membrane components face serious membrane pollution and blockage problems, and need to be regularly returned for cleaning, and the cost of membrane components is expensive. The membrane aeration process mainly uses commercial hollow fiber membranes as microbial attachment carriers. The membrane components are expensive and have large gas diffusion resistance. A high-pressure gas source is required to drive oxygen transmission to supply oxygen to the microbial membrane.

[0004] Therefore, in view of the problems of high aeration energy consumption, serious sludge loss and large area of ​​secondary sedimentation tank in the existing activated sludge process, as well as the challenges faced by the existing membrane process such as high membrane component cost, high-pressure air source requirement and easy clogging, it is necessary to conduct in-depth research on air self-diffusion microbial membranes that can be used for sewage treatment. Summary of the invention

[0005] In view of this, one of the objects of the present invention is to provide an air-diffusion microbial membrane for sewage treatment; a second object of the present invention is to provide a method for preparing an air-diffusion microbial membrane for sewage treatment; a third object of the present invention is to provide an application of an air-diffusion microbial membrane for sewage treatment in simultaneous nitrification-denitrification adaptive denitrification.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] 1. An air-diffusion microbial membrane for sewage treatment, the air-diffusion microbial membrane comprising a hydrophobic layer, an adhesive layer, a hydrophilic layer and a microbial layer from the outside to the inside,

[0008] The bonding layer has the functions of supporting, connecting the waterproof layer and the hydrophilic layer, and being waterproof and breathable. The air diffusion flux size in the air self-diffusion microbial membrane is regulated by adjusting the thickness of the bonding layer.

[0009] Preferably, the bonding layer is prepared according to the following method:

[0010] (1) Slurry preparation: a hydrophobic powder with a particle size of 200 mesh or more is used as a slurry raw material, ethanol and water are added in sequence for dispersion to obtain a slurry, wherein the mass ratio of the slurry raw material, ethanol and water is 1:4 to 7:4, and then a PTFE emulsion or a Nafion aqueous solution is added as a slurry binder to bond the slurry, and the slurry is stirred and kneaded into a plasticine-textured material, wherein the mass ratio of the raw material slurry to the binder is 1:1.5 to 3;

[0011] (2) Pressing and forming a film: placing the plasticine texture material in step (1) in molds of different thicknesses, rolling and pressing it to flatten and spread it out to form a film to obtain a bonding layer; the mold is obtained by milling a groove with a depth of 0.2 to 1.3 mm on the surface of a hard plate, wherein the hard plate is stainless steel or organic glass;

[0012] The hydrophobic powder includes any one of carbon black, activated carbon, sulfur powder or polymer high molecular powder material or a combination of several materials. The polymer high molecular powder material is any one of polypropylene (PP), polyamide (PA), polyphenylene ether (PPO), ABS plastic or polytetrafluoroethylene (PTFE).

[0013] Preferably, the material of the hydrophobic layer is a waterproof and breathable film formed by any one of polytetrafluoroethylene, polyvinylidene fluoride, ultra-high molecular weight polyethylene, polyethylene terephthalate or polypropylene, or a composite of several of them.

[0014] Preferably, the hydrophilic layer is made of non-woven fabric, carbon cloth or carbon felt.

[0015] 2. The preparation method of the above-mentioned air self-diffusion microbial film comprises any one of the following methods 1 or 2:

[0016] Method 1: Press the hydrophobic layer and the hydrophilic layer materials onto the front and back sides of the adhesive layer respectively, compact them by a cold laminator or a sheet press, and burn them at 140-220°C for 2-5 hours; brush or spray a viscous slurry containing bacterial powder or a viscous slurry containing an activated sludge mixture obtained from a sewage treatment plant onto the surface of the hydrophilic layer to form a microbial layer, thereby obtaining an air self-diffusion microbial film.

[0017] Method 2: First, select two or more materials of any hydrophobic layer to form a composite membrane, and press two or three layers of composite membrane into one layer by high-temperature hot-melt pressing to achieve thickness control and improve waterproof performance; then evenly apply a layer of adhesive on the surface of any side of the pressed membrane, and then hot-press and bond the hydrophilic layer material; finally, brush or spray a viscous slurry containing bacterial powder or a viscous slurry containing an activated sludge mixture obtained from a sewage treatment plant onto the surface of the hydrophilic layer to form a microbial layer, thereby obtaining an air self-diffusion microbial membrane.

[0018] Preferably, the preparation method further comprises performing a hydrophilic treatment on the hydrophilic layer, and the specific method is: using an amino-containing silane coupling agent as a hydrophilic agent, preparing a dilute hydrophilic agent solution with a volume fraction of 2% to 5% with ethanol, spraying the solution onto the surface of the hydrophilic layer or soaking the hydrophilic layer with the solution, and then drying the solution at 60 to 80° C. for 30 to 90 minutes;

[0019] The amino-containing silane coupling agent is any one of 3-aminopropyltrimethoxysilane, 4-amino-3, 3-dimethylbutyltrimethoxysilane or γ-aminopropyltriethoxysilane.

[0020] Preferably, the mass ratio of bacterial powder, sodium carboxymethyl cellulose and water in the viscous slurry containing bacterial powder is 2-4:2:25-50;

[0021] The preparation method of the viscous slurry containing the activated sludge mixed liquor obtained from the sewage treatment plant is as follows: the activated sludge obtained from the sewage treatment plant is concentrated to a sludge concentrate having an MLSS of 1.5 to 3 g / L, and sodium cellulose is added according to the standard of adding 0.05 g of sodium cellulose per milliliter of the sludge concentrate to prepare a viscous slurry containing the activated sludge mixed liquor obtained from the sewage treatment plant;

[0022] The microbial layer in the air diffusion microbial membrane is prepared by a suspension inoculation or immobilization method. The specific operation of suspension inoculation is: a suspension containing bacterial powder with an MLSS of 1.5-3g / L or a suspension containing activated sludge obtained from a sewage treatment plant is directly added into the reactor, and the microorganisms are naturally attached to the hydrophilic layer material under stirring to form a microbial layer.

[0023] 3. Application of the above-mentioned air self-diffusion microbial membrane in simultaneous nitrification-denitrification adaptive denitrification.

[0024] Preferably, the startup method of the synchronous nitrification-denitrification adaptive denitrification is: ① Step-by-step startup: assemble the air self-diffusion microbial membrane to the reaction device, first batch culture under the condition of ammonia nitrogen influent to achieve the startup and stabilization of the nitrification function, and then +The mass ratio of COD and NH4 is 1-3:1, and a carbon source is added to the influent, wherein the carbon source is any one of sodium acetate, sucrose or glucose, to culture denitrifying functional bacteria; ② Synchronous start: according to the COD and NH4 + The mass ratio of is 1 to 3, and ammonia nitrogen and carbon source are added to the influent conditions to start synchronously.

[0025] The beneficial effects of the present invention are as follows: the present invention discloses an air self-diffusion microbial membrane for sewage treatment, which includes a hydrophobic layer, an adhesive layer, a hydrophilic layer and a microbial layer from the outside to the inside, wherein the adhesive layer has the functions of supporting, connecting the waterproof layer and the hydrophilic layer, being waterproof and breathable, and the air diffusion flux size is regulated by adjusting the thickness of the adhesive layer in the air self-diffusion microbial membrane. The present invention realizes air diffusion from the hydrophobic layer side to the hydrophilic layer side by constructing an air self-diffusion microbial membrane, replacing the traditional aeration or mechanical aeration oxygen supply mode; at the same time, the present invention enhances its hydrophilicity and microbial biofilm performance by modifying the hydrophilic layer material, thereby improving the loading capacity of microorganisms. The air self-diffusion microbial membrane for sewage treatment disclosed by the present invention has low preparation cost, simple process construction when used for sewage treatment, no aeration, secondary sedimentation tank and geotechnical construction, etc., can reduce the investment cost and operation cost of sewage treatment.

[0026] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0028] Figure 1 This is a structural diagram of the air self-diffusion microbial membrane used for sewage treatment in Example 1;

[0029] Figure 2 This is a flow chart of the preparation of an air self-diffusion microbial membrane for sewage treatment in Example 1;

[0030] Figure 3 An air-diffusion microbial membrane reactor containing the air-diffusion microbial membrane for sewage treatment in Example 1;

[0031] Figure 4 To use Figure 3 The dissolved oxygen curve measured by the air self-diffusion biofilm reactor;

[0032] Figure 5To use Figure 3 The nitrification performance curve of the air self-diffusion microbial membrane reactor;

[0033] Figure 6 To use Figure 3 Performance curve of simultaneous nitrification-denitrification in the air self-diffusion microbial membrane reactor. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0035] Example 1

[0036] An air diffusion microbial membrane for sewage treatment (its structure is as follows Figure 1 The preparation process is as shown in Figure 2 As shown, it is prepared according to the following method:

[0037] (1) Preparation of bonding layer material: Add carbon black (particle size greater than or equal to 200 mesh), water and ethanol in a mass ratio of 1:4:4 into a glass bottle, fully disperse the carbon black powder by shaking and ultrasonication to obtain a carbon black slurry, and then add PTFE emulsion into the prepared carbon black slurry in a mass ratio of carbon black to PTFE emulsion of 1:1.5, shake and mix evenly, and stir thoroughly with a glass rod to form a material with a plasticine texture, which is the bonding layer material.

[0038] (2) Preparation of bonding layer: Select a mold as needed. In this embodiment, a mold with a size of 60 mm*50 mm*0.3 mm is selected. To control the uniform thickness of the bonding layer, 5 g of the bonding layer material is weighed and placed in the mold (such as Figure 2 Then, the adhesive layer material is rolled and flattened in the mold to form a film (such as Figure 2 In step 2, a bonding layer is prepared, which can be made into a large-sized bonding layer by splicing (such as Figure 2 Step 3) in the above example can meet the actual needs.

[0039] (3) Pressing, firing and modification (such as Figure 2Step 4~7): Use commercial PTFE waterproof film (thickness between 200um~300um) as the waterproof layer and cheap and easily available cotton non-woven fabric as the hydrophilic layer. Use a cold laminator to press the PTFE film and non-woven fabric to the front and back sides of the adhesive layer, and then burn it at 220℃ for 2h. The fired film is placed in a 2% dilute solution of 3-aminopropyltrimethoxysilane hydrophilic reagent (ethanol preparation), soaked for 10min, and then taken out and dried at 80℃ for 30min.

[0040] (4) Preparation of microbial layer (inoculation): Add bacterial powder, sodium carboxymethyl cellulose and water in a mass ratio of 2:1:50 into a beaker to prepare a viscous slurry, which is then applied to one side of the hydrophilic layer (e.g. Figure 2 In step 8), a microbial layer is formed to obtain an air self-diffusion microbial membrane for standby use.

[0041] Example 2

[0042] An air self-diffusion microbial membrane for sewage treatment is prepared according to the following method:

[0043] (1) Preparation of bonding layer material: Add carbon black (particle size greater than or equal to 200 mesh), water and ethanol in a mass ratio of 1:4:7 into a glass bottle, fully disperse the carbon black powder by shaking and ultrasonication to obtain a carbon black slurry, then add PTFE emulsion binder into the prepared carbon black slurry in a mass ratio of carbon black to PTFE emulsion of 1:3, shake and mix evenly, and stir with a glass rod to form a material with a plasticine texture, which is the bonding layer material.

[0044] (2) Preparation of bonding layer: A mold is selected as required. In this embodiment, a mold with a size of 60 mm*50 mm*0.5 mm is selected. To control the uniform thickness of the bonding layer, 7 g of the bonding layer material is weighed and placed in the mold. The bonding layer material is then rolled and flattened in the mold to form a film to prepare the bonding layer. A large-sized bonding layer can be made by splicing to meet actual needs.

[0045] (3) Lamination, firing and modification: A commercial PTFE waterproof film (thickness between 200um and 300um) was used as the waterproof layer, and a cheap and easily available cotton non-woven fabric was used as the hydrophilic layer. The PTFE film and the non-woven fabric were pressed and bonded to the front and back sides of the adhesive layer by a cold laminator, and then fired at 150°C for 5h. The fired film was placed in a 2% dilute solution of 3-aminopropyltrimethoxysilane hydrophilic reagent (ethanol preparation), soaked for 15min, and then taken out and dried at 80°C for 30min.

[0046] (4) Preparation of microbial layer (inoculation): Add bacterial powder, sodium carboxymethyl cellulose and water in a mass ratio of 1:1:25 into a beaker to prepare a viscous slurry, which is then applied to one side of the hydrophilic layer to form a microbial layer to prepare an air-diffusion microbial membrane for standby use.

[0047] Example 3

[0048] An air self-diffusion microbial membrane for sewage treatment, the specific preparation method is as follows:

[0049] Firstly, two hydrophobic layer materials of ethylene (PTFE) and polypropylene (PP) are selected to form a composite membrane, and the two layers of the composite membrane are pressed into one layer by high-temperature hot-melt pressing to achieve thickness control and improve waterproof performance; then a layer of PTFE emulsion adhesive is evenly applied on the surface of either side of the pressed membrane, and then the hydrophilic layer material is hot-pressed and hydrophilic modified to enhance the microbial biofilm performance; finally, a viscous slurry containing an activated sludge mixture obtained from a sewage treatment plant (the preparation method is: the activated sludge obtained from the sewage treatment plant is concentrated to a sludge concentrate with an MLSS of 1.5 g / L, and cellulose sodium is added according to the standard of adding 0.05 g cellulose sodium per milliliter of sludge concentrate to prepare a viscous slurry containing an activated sludge mixture obtained from the sewage treatment plant) is sprayed on the surface of the hydrophilic layer to form a microbial layer, and an air self-diffusion microbial membrane can be obtained.

[0050] Example 4

[0051] An air self-diffusion microbial membrane for sewage treatment, the specific preparation method is as follows:

[0052] Firstly, three hydrophobic layer materials of polyvinylidene fluoride (PVDF), ultra-high molecular weight polyethylene (UHMWPE) and polyethylene terephthalate (PET) are selected to form a composite membrane, and the three-layer composite membrane is pressed into one layer by high-temperature hot-melt pressing to achieve thickness control and improve waterproof performance; then a layer of PTFE emulsion adhesive is evenly applied on the surface of either side of the pressed membrane, and then the hydrophilic layer material is hot-pressed and laminated; finally, a viscous slurry containing an activated sludge mixture obtained from a sewage treatment plant (the preparation method is: the activated sludge obtained from the sewage treatment plant is concentrated to a sludge concentrate with an MLSS of 3g / L, and cellulose sodium is added according to the standard of adding 0.05g cellulose sodium per milliliter of sludge concentrate to prepare a viscous slurry containing an activated sludge mixture obtained from the sewage treatment plant) is sprayed on the surface of the hydrophilic layer to form a microbial layer, and an air self-diffusion microbial membrane can be obtained.

[0053] Performance Testing

[0054] An air diffusion microbial membrane reactor, such as Figure 3As shown, specifically: the hydrophobic layer of the air self-diffusion microbial membrane for sewage treatment prepared in Example 1 is facing the air side and assembled to both sides of the reactor for rapid start-up to achieve rapid degradation of pollutants. Air freely diffuses through the membrane assembly to provide oxygen for aerobic microorganisms without the need for external aeration facilities; the gas flux can be controlled by adjusting the thickness of the biofilm, and the oxygen concentration extends from the membrane surface to the liquid chamber to form an aerobic-anaerobic / anoxic gradient; on the dissolved oxygen gradient, nitrification reaction (aerobic) and denitrification reaction (anaerobic) are directed in a confined space to transfer mass, achieving adaptive denitrification without any manual intervention such as effluent reflux; in actual applications, each reactor is used as an independent treatment device, which is amplified by stacking reactors in series / parallel, without the need for the construction process of the traditional activated sludge process, and the engineering construction is simple and fast, with the ability to face decentralized sewage treatment. The flow of liquid (sewage) between reactor units is controlled to achieve the continuity of sewage treatment.

[0055] 1. Zero-power air self-diffusion oxygen supply test

[0056] Using the above Figure 3 The reactor configuration in the reactor was assembled with air diffusion microbial membranes on both sides of the reactor for air diffusion oxygen supply test (the thickness of the air diffusion biofilm used in this test was 0.3 mm). The dissolved oxygen curve measured by the reactor was as follows: Figure 4 As shown in the figure, air can freely diffuse through the biofilm to transport oxygen into the reactor without the need for additional aeration power, and the solution (180 mL) can reach dissolved oxygen saturation in a short time (150 min).

[0057] 2. Membrane respiration nitrification

[0058] The above-mentioned air self-diffusion microbial membrane reactor was used to carry out membrane respiration nitrification (NH4 + →NO3 - ), the effective area of ​​the air self-diffusion microbial membrane in the reactor is 60cm 2 The membrane thickness is 0.3mm, and the total volume of the reactor is 0.18L. The air diffusion microbial membrane is assembled on both sides of the reactor, and the suspended sludge is inoculated to form functional bacteria to start the nitrification reactor. After 2-3 days of biofilm formation, the sludge suspension in the reactor is discharged, and the microorganisms on the biofilm are used as the main body of nitrification functional bacteria; the oxygen required for nitrification is provided by air diffusion, and there is no additional aeration facility. In this application, the influent NH4 + The concentration is 100 mg / L. The reactor is operated in batch mode with a hydraulic retention time of 24 h. The nitrification performance curve is as follows: Figure 5 As shown in the figure, a stable nitrifying biofilm can be formed in about 15 to 20 days; the NH4 + Can be completely converted into NO3 -The ammonia nitrogen removal efficiency (NRR) is as high as about 80%, and the nitrification is stable during the operation time of more than 80 days. This shows that the air self-diffusion microbial membrane for sewage treatment prepared by the present invention can realize zero-power air self-diffusion oxygen supply to provide oxygen for microorganisms, and realize the rapid start-up and stable operation of nitrification.

[0059] 3. Simultaneous nitrification-denitrification

[0060] The above-mentioned air self-diffusion microbial membrane reactor was used to carry out membrane respiration synchronous nitrification-denitrification (NH4 + →N2). The effective area of ​​the air self-diffusion microbial membrane in the reactor is 60cm 2 , membrane thickness is 0.3mm, and the total volume of the reactor is 0.18L. In this implementation case, the nitrification reaction is started and stabilized by a step-by-step start-up method, specifically: air self-diffusion microbial membranes coated with nitrifying bacteria liquid are assembled on both sides of the reactor to start the reaction, and NH4 + The concentration was 100 mg / L, and the reactor was operated in batch mode with a hydraulic retention time of 24 h. After the nitrification was stabilized, the influent was adjusted according to COD / NH4 + =3, add carbon source to start denitrification, and sodium acetate is selected as the carbon source. The performance curve of simultaneous nitrification-denitrification is as follows Figure 6 As shown in the figure, nitrification is started within 15 to 20 days. After stabilization, adding sodium acetate as a carbon source can quickly start denitrification within 1 to 2 days. Air self-diffusion penetrates the respiratory membrane to supply oxygen to the reactor, and the oxygen concentration extends from the membrane surface to the liquid chamber to form an aerobic-anaerobic / anoxic gradient; on the dissolved oxygen gradient, nitrification reaction (aerobic) and denitrification reaction (anaerobic) are directed in a confined space to achieve adaptive denitrification. NH4 in the solution + It can be completely converted into N2, with a total nitrogen removal efficiency (TNR) of up to about 100%, and the synchronous nitrification-denitrification is stable during the operation time of more than 80 days. This shows that the air self-diffusion microbial membrane for sewage treatment prepared by the present invention can realize zero-power air self-diffusion oxygen supply and can realize the rapid start-up and stable operation of synchronous nitrification-denitrification in a confined space.

[0061] Similarly, the air-diffusion microbial membranes for sewage treatment prepared by different preparation methods in the above-mentioned Examples 2, 3 and 4 were also subjected to the above-mentioned performance test, and the results were similar to the performance test results of the air-diffusion microbial membranes for sewage treatment in the above-mentioned Example 1.

[0062] In addition, the hydrophobic powder used in the bonding layer in Examples 1 to 2 can be replaced by any one or a combination of carbon black, activated carbon, sulfur powder or polymer powder material (wherein the polymer powder material is any one of polypropylene (PP), polyamide (PA), polyphenylene ether (PPO), ABS plastic or polytetrafluoroethylene (PTFE)) to prepare an air-diffusing microbial membrane for sewage treatment, and its performance is similar to that of the air-diffusing microbial membrane for sewage treatment prepared in Examples 1 to 4.

[0063] In summary, the present invention discloses an air self-diffusion microbial membrane for sewage treatment, which includes a hydrophobic layer, an adhesive layer, a hydrophilic layer and a microbial layer from the outside to the inside, wherein the adhesive layer has the functions of supporting, connecting the waterproof layer and the hydrophilic layer, being waterproof and breathable, and the air diffusion flux size is regulated by adjusting the thickness of the adhesive layer in the air self-diffusion microbial membrane. The present invention realizes the diffusion of air from the hydrophobic layer side to the hydrophilic layer side by constructing an air self-diffusion microbial membrane, replacing the traditional aeration or mechanical aeration oxygen supply mode; at the same time, the present invention enhances its hydrophilicity and microbial biofilm performance by modifying the hydrophilic layer material, thereby improving the loading capacity of microorganisms. The air self-diffusion microbial membrane for sewage treatment disclosed by the present invention has low preparation cost, simple process construction when used for sewage treatment, no aeration, secondary sedimentation tank and geotechnical construction, etc., can reduce the investment cost and operation cost of sewage treatment.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. An air-diffusion microbial membrane for sewage treatment, characterized in that: The air self-diffusion microbial membrane includes a hydrophobic layer, an adhesive layer, a hydrophilic layer and a microbial layer from the outside to the inside. The bonding layer has the functions of supporting and connecting the waterproof layer and the hydrophilic layer, and is waterproof and breathable. The air diffusion flux size in the air self-diffusion microbial membrane is regulated by adjusting the thickness of the bonding layer; The bonding layer is prepared as follows: (1) Slurry preparation: a hydrophobic powder with a particle size of 200 mesh or more is used as a slurry raw material, ethanol and water are added in sequence for dispersion to obtain a slurry, wherein the mass ratio of the slurry raw material, ethanol and water is 1:4 to 7:4, and then a PTFE emulsion or a Nafion aqueous solution is added as a slurry binder to bond the slurry, and the slurry is stirred and kneaded into a plasticine-textured material, wherein the mass ratio of the raw material slurry to the binder is 1:1.5 to 3; (2) Pressing and forming a film: placing the plasticine texture material in step (1) in molds of different thicknesses, rolling and pressing it to flatten and spread it out to form a film to obtain a bonding layer; the mold is obtained by milling a groove with a depth of 0.2 to 1.3 mm on the surface of a hard plate, wherein the hard plate is stainless steel or organic glass; The hydrophobic powder includes any one of carbon black, activated carbon, sulfur powder or polymer high molecular powder material or a combination of several materials. The polymer high molecular powder material is any one of polypropylene, polyamide, polyphenylene ether, ABS plastic or polytetrafluoroethylene.

2. The air-diffusion microbial membrane according to claim 1, characterized in that: The material of the hydrophobic layer is a waterproof and breathable film formed by any one of polytetrafluoroethylene, polyvinylidene fluoride, ultra-high molecular weight polyethylene, polyethylene terephthalate or polypropylene, or a composite of several of them.

3. The air-diffusing microbial membrane according to claim 1, characterized in that: The hydrophilic layer is made of non-woven fabric, carbon cloth or carbon felt.

4. The method for preparing the air self-diffusion microbial film according to any one of claims 1 to 3, characterized in that: The preparation method comprises any one of the following methods 1 or 2, Method 1: Press the hydrophobic layer and the hydrophilic layer materials onto the front and back sides of the adhesive layer respectively, compact them by a cold laminator or a sheet press, and burn them at 140-220℃ for 2-5h; brush or spray a viscous slurry containing bacterial powder or a viscous slurry containing an activated sludge mixture obtained from a sewage treatment plant onto the surface of the hydrophilic layer to form a microbial layer, thereby obtaining an air self-diffusion microbial membrane. Method 2: First, two or more materials of any hydrophobic layer are selected to form a composite film, and two or three layers of composite films are pressed into one layer by high-temperature hot-melt pressing to achieve thickness control and improve waterproof performance; Then, a layer of adhesive is evenly applied on the surface of either side of the pressed membrane, and the hydrophilic layer material is hot-pressed and laminated; finally, a viscous slurry containing bacterial powder or a viscous slurry containing an activated sludge mixture obtained from a sewage treatment plant is applied or sprayed onto the surface of the hydrophilic layer to form a microbial layer, thereby obtaining an air self-diffusion microbial membrane.

5. The preparation method according to claim 4, characterized in that: The preparation method further comprises performing a hydrophilic treatment on the hydrophilic layer, and the specific method is: using an amino-containing silane coupling agent as a hydrophilic agent, preparing a dilute hydrophilic agent solution with a volume fraction of 2% to 5% with ethanol, spraying the solution onto the surface of the hydrophilic layer or soaking the hydrophilic layer with the solution, and then drying the solution at 60 to 80° C. for 30 to 90 minutes; The amino-containing silane coupling agent is any one of 3-aminopropyltrimethoxysilane, 4-amino-3, 3-dimethylbutyltrimethoxysilane or γ-aminopropyltriethoxysilane.

6. The preparation method according to claim 4, characterized in that: The mass ratio of the bacterial powder, sodium carboxymethyl cellulose and water in the viscous slurry containing the bacterial powder is 2-4:2:25-50; The preparation method of the viscous slurry containing the activated sludge mixed liquor obtained from the sewage treatment plant is as follows: the activated sludge obtained from the sewage treatment plant is concentrated to a sludge concentrate having an MLSS of 1.5 to 3 g / L, and sodium cellulose is added according to the standard of adding 0.05 g of sodium cellulose per milliliter of the sludge concentrate to prepare a viscous slurry containing the activated sludge mixed liquor obtained from the sewage treatment plant; The microbial layer in the air diffusion microbial membrane is prepared by a suspension inoculation or immobilization method. The specific operation of suspension inoculation is: a suspension containing bacterial powder with an MLSS of 1.5-3g / L or a suspension containing activated sludge obtained from a sewage treatment plant is directly added into the reactor, and the microorganisms are naturally attached to the hydrophilic layer material under stirring to form a microbial layer.

7. Application of the air self-diffusion microbial membrane according to any one of claims 1 to 3 in simultaneous nitrification-denitrification adaptive denitrification.

8. The use according to claim 7, characterized in that: The startup method of the synchronous nitrification-denitrification adaptive denitrification is as follows: ① Step-by-step startup: assemble the air self-diffusion microbial membrane onto the reaction device, first batch culture under the condition of ammonia nitrogen influent to achieve the startup and stabilization of the nitrification function, and then + The mass ratio of COD and NH4 is 1-3:1, and a carbon source is added to the influent, wherein the carbon source is any one of sodium acetate, sucrose or glucose, to culture denitrifying functional bacteria; ② Synchronous start: according to COD and NH4 + The mass ratio is 1~3, and ammonia nitrogen and carbon source are added to the inlet water conditions to start synchronously.

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