Composite biological carrier for town sewage treatment

Abstract

The invention discloses a composite biological carrier for town sewage treatment, which is characterized in that bamboo fiber, acrylic fiber, hydrophilic polyurethane and ethylene-vinyl acetate copolymer are subjected to five-layer laminated treatment from top to bottom: the first layer is a bamboo fiber and acrylic fiber composite layer, and the second layer is a hydrophilic polyurethane and ethylene-vinyl acetate copolymer composite layer; the first layer is an ethylene-vinyl acetate copolymer layer, the second layer is an ethylene-vinyl acetate copolymer layer, the third layer is a bamboo fiber and acrylic fiber composite layer, the fourth layer is a hydrophilic polyurethane layer, the fifth layer is a bamboo fiber and acrylic fiber composite layer, and the bamboo fiber and acrylic fiber composite layers of the first layer, the third layer and the fifth layer are different in thickness and are reinforced by adopting an air entanglement method. Denitrification phosphorus-accumulating bacteria are respectively subjected to biofilm culturing on the first, third and fifth bamboo fiber and acrylic fiber composite layers, then the first, second, third, fourth and fifth layers are reinforced by adopting a spunlace and air thorn combination method, and the four materials are subjected to five-layer laminated treatment to obtain the composite biological carrier, so that the nitrogen and phosphorus removal rate of town sewage is more favorably improved.

Description

Technical Field

[0001] The present invention relates to the field of urban sewage treatment, and particularly refers to a composite biological carrier capable of effectively removing nitrogen and phosphorus in urban sewage. Background Art

[0002] At present, urban sewage contains a large amount of nitrogen-containing compounds, phosphate and other pollutants. If the nitrogen-containing compounds and phosphate are not treated in time or the treatment effect is not good, it will cause serious harm to humans and the entire ecological environment.

[0003] Since the current biological carriers have limited effects on removing nitrogen and phosphorus in urban sewage: on the one hand, regarding the structure of the biological carrier: biological carriers are mostly used in the biological contact oxidation method. Several commonly used fillers in biological contact oxidation tanks include plate fillers, honeycomb fillers, fiber combination fillers, three-dimensional elastic fillers, etc. Single fibrous fillers such as polyester and nylon will have agglomeration problems during use; for fiber combination fillers, they usually consist of a connecting rope, a fiber support, a fiber bundle, and a support tube. This structure usually gets entangled and forms agglomeration when the water flow velocity is slow or the bubbles are large, thus greatly reducing the effect of using the filler to treat sewage. On the other hand, regarding the types of biological carriers: there are various biological carriers in urban sewage treatment, such as inorganic biological membrane carriers, organic synthetic polymer biological membrane carriers, and natural biodegradable polymer biological membrane carriers. Commonly used inorganic carriers include carbon fiber, activated carbon, zeolite, ceramics, slag, etc. However, inorganic biological membrane carriers often have a relatively large density, are not suitable for fluidized movement, and have relatively single surface properties; commonly used organic synthetic polymers include polyvinyl chloride, polypropylene resin, plastics, etc. Currently, the commonly used suspended fillers in biological contact oxidation tanks are made of polyethylene and polypropylene, but their production cost is high, the production process is complex, and their durability is poor. They need to be replaced in time and are also prone to causing secondary pollution to the environment; natural biodegradable polymers are mainly cellulose, chitosan, protein membranes, etc., but their mechanical strength is low, their service life is short, and the sources of some natural polymer materials are limited. Therefore, it is necessary to develop a composite biological carrier capable of effectively removing nitrogen and phosphorus in urban sewage for urban sewage treatment. Summary of the Invention

[0004] The purpose of the present invention is to provide a composite biological carrier capable of effectively removing nitrogen and phosphorus in urban sewage.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] (1) Take four materials: bamboo fiber, acrylic fiber, hydrophilic polyurethane, and ethylene-vinyl acetate copolymer, and perform a 5-layer lamination treatment. From top to bottom, they are: the first layer is a composite layer of bamboo fiber and acrylic fiber, the second layer is an ethylene-vinyl acetate copolymer layer, the third layer is a composite layer of bamboo fiber and acrylic fiber, the fourth layer is a hydrophilic polyurethane layer, and the fifth layer is a composite layer of bamboo fiber and acrylic fiber.

[0007] (2) For the composite layers of bamboo fiber and acrylic fiber in the first, third, and fifth layers, respectively, use the air-jet needling method for reinforcement, and make composite layers of bamboo fiber and acrylic fiber with the same length and width but different thicknesses. By adjusting the thicknesses of bamboo fiber and acrylic fiber in the bamboo fiber and acrylic fiber composite layers, the thickness of the bamboo fiber and acrylic fiber composite layers can be changed.

[0008] (3) The process parameters in the air-jet needling method, such as air pressure and jet speed, etc., are optimized and designed to meet the mechanical strength of the composite layer of bamboo fiber and acrylic fiber. The air pressure is 0.4 MPa to 1.0 MPa, the pore diameter of the air-jet needle outlet is 1 mm, the jet speed is between 60 m / s and 110 m / s, the distance between air-jet needles is between 10 mm and 12 mm, and the air-jet frequency is 150 times per minute; among them, the air pressure P a and the temperature T satisfy a specific functional relationship: P a = |-3T + 200|, 200 ≤ T ≤ 400; the jet speed ν of the air-jet needling method and the time t satisfy a specific functional relationship: ν = |-70t + 10|, 1 < t < 3.

[0009] (4) Perform three-step treatment on the first, third, and fifth composite layers of bamboo fiber and acrylic fiber reinforced by the air-jet needling method respectively: the first step is to wash with distilled water for 6 minutes, the second step is to sterilize in high-pressure steam at 121 °C and 103.4 KPa for 20 minutes, and the third step is to dry in an oven at 60 °C for 2 hours.

[0010] (5) Use Acinetobacter junii with denitrifying polyphosphorus to perform static immersion inoculation and biofilm formation treatment on the first, third, and fifth composite layers of bamboo fiber and acrylic fiber after the three-step treatment: Configure Acinetobacter junii with denitrifying polyphosphorus into a bacterial suspension with a concentration of 10 5 CFU / mL to 10 7 CFU / mL. Immerse the first, third, and fifth composite layers of bamboo fiber and acrylic fiber into the prepared bacterial suspension respectively, and the immersion time is 24 hours each. By controlling the concentration of the bacterial suspension and the thickness of the composite layer of bamboo fiber and acrylic fiber, three microbial films with different thicknesses can be obtained on the first, third, and fifth composite layers of bamboo fiber and acrylic fiber, thereby improving the nitrogen and phosphorus removal rate of the composite biological carrier for municipal sewage.

[0011] (6) The bamboo fiber acrylic fiber composite layers of the first, third, and fifth layers after biofilm attachment, a layer of ethylene-vinyl acetate copolymer with a certain thickness, and a layer of hydrophilic polyurethane with a certain thickness are arranged from top to bottom in the following order: the first layer is the bamboo fiber and acrylic fiber composite layer, the second layer is the ethylene-vinyl acetate copolymer layer, the third layer is the bamboo fiber and acrylic fiber composite layer, the fourth layer is the hydrophilic polyurethane layer, and the fifth layer is the bamboo fiber and acrylic fiber composite layer. They are reinforced by the method of first air-needling and then water-needling. Process parameters such as the water jet pressure and the diameter of the water jet holes are optimized and designed, and the microbial film on the bamboo fiber and acrylic fiber composite layer will not be damaged; the water jet pressure is from 70 bar to 165 bar, the diameter of the water jet holes is from 0.1 mm to 0.4 mm, the water-needling distance is between 6 mm and 9 mm, and the water-needling frequency is 300 times per minute; the air pressure is from 0.4 MPa to 0.6 MPa, the pore diameter of the air jet nozzle of the air jet needle is 1 mm, the air jet speed is between 60 m / s and 110 m / s, the distance between the air-needling heads is between 10 mm and 12 mm, and the air-needling frequency is 150 times per minute; among them, the water jet pressure P w of the water-needling method and the water jet speed ω satisfy P w = (ω + 2) 2 + 21, 5 ≤ ω ≤ 10; there is a specific functional relationship between the water jet speed and the diameter of the water jet holes in the water-needling method: ω = -2.4g + 3.3, 0.1 ≤ g ≤ 0.4.

[0012] (7) Put the composite biological carrier in this patent after reinforcement into urban sewage. The dissolved oxygen in the anaerobic section of the urban sewage needs to be strictly controlled below 0.2 mg / L, the dissolved oxygen concentration in the anoxic section needs to be strictly controlled below 0.5 mg / L, and the pH values in both the anaerobic section and the anoxic section need to be controlled between 7 and 8. Among them, there is a specific relationship between the dissolved oxygen concentration x1 in the anaerobic section and the dissolved oxygen concentration x2 in the anoxic section and the nitrogen and phosphorus removal rate γ of the composite biological carrier in this patent: 0 < x1 < 0.2, 0 < x2 < 0.5.

[0013] Advantages of the present invention: The raw materials are widely sourced and low in cost, not prone to agglomeration, with good durability, good hydrophilicity, easy to degrade and will not cause secondary pollution to the environment. By using Acinetobacter junii with denitrifying phosphorus removal to attach a biofilm to the composite biological carrier in this patent, the nitrogen and phosphorus removal effect of the composite biological carrier in this patent on urban sewage is improved. Description of the Drawings

[0014] In order to further illustrate the technical solutions in the embodiments of the present invention, the drawings in the embodiments will be briefly introduced below. The drawings are only partial embodiments of the present invention.

[0015] Figure 1It is a schematic structural diagram of a composite biological carrier for urban sewage treatment in an embodiment of the present invention.

[0016] Figure 2 It is a schematic process diagram of a composite biological carrier for urban sewage treatment in an embodiment of the present invention. Specific embodiments

[0017] In order to further describe the present invention in detail, the technical solutions of the present invention will be further described below through specific embodiments.

[0018] As Figure 1 shown, a composite biological carrier for urban sewage treatment is divided into 5 layers, from top to bottom in turn: the first layer is a composite layer of bamboo fiber and acrylic fiber, the second layer is an ethylene-vinyl acetate copolymer layer, the third layer is a composite layer of bamboo fiber and acrylic fiber, the fourth layer is a hydrophilic polyurethane layer, and the fifth layer is a composite layer of bamboo fiber and acrylic fiber; and the thickness of each layer varies due to various process parameters in the hydrospinning method and the needling method.

[0019] As Figure 2 shown, the process of a composite biological carrier for urban sewage treatment is divided into 7 steps in turn: material preparation, air-needling reinforcement, pretreatment, film hanging, determination of denitrification and phosphorus removal rates, combined hydrospinning and air-needling reinforcement, determination of denitrification and phosphorus removal rates. Material preparation includes bamboo fiber, acrylic fiber, ethylene-vinyl acetate copolymer, and hydrophilic polyurethane; air-needling reinforcement is to reinforce the composite layers of bamboo fiber and acrylic fiber in the first, third, and fifth layers; pretreatment includes the first step: washing with distilled water, the second step: high-pressure steam sterilization, and the third step: drying in an oven; film hanging: selecting Acinetobacter junii for denitrifying phosphorus removal to hang the film on the reinforced composite layers of bamboo fiber and acrylic fiber in the first, third, and fifth layers; determination of denitrification and phosphorus removal rates: determining the denitrification and phosphorus removal rates of the composite layers of bamboo fiber and acrylic fiber in the first, third, and fifth layers after film hanging; combined hydrospinning and air-needling reinforcement: reinforcing the first, second, third, fourth, and fifth layers; determination of denitrification and phosphorus removal rates: determining the composite biological carrier in this patent.

[0020] Example 1

[0021] (1) Take four materials of bamboo fiber, acrylic fiber, hydrophilic polyurethane, and ethylene-vinyl acetate copolymer for 5-layer laminated treatment. From top to bottom in turn: the first layer is a composite layer of bamboo fiber and acrylic fiber, the second layer is an ethylene-vinyl acetate copolymer layer, the third layer is a composite layer of bamboo fiber and acrylic fiber, the fourth layer is a hydrophilic polyurethane layer, and the fifth layer is a composite layer of bamboo fiber and acrylic fiber.

[0022] (2) In the first layer of bamboo fiber and acrylic fiber composite layer, the thickness of bamboo fiber is 2.8 mm and the thickness of acrylic fiber is 0.8 mm; the thickness of the second layer of ethylene-vinyl acetate copolymer layer is 2.3 mm; in the third layer of bamboo fiber and acrylic fiber composite layer, the thickness of bamboo fiber is 2.7 mm and the thickness of acrylic fiber is 0.7 mm; the thickness of the fourth layer of hydrophilic polyurethane layer is 2.3 mm; in the fifth layer of bamboo fiber and acrylic fiber composite layer, the thickness of bamboo fiber is 2.6 mm and the thickness of acrylic fiber is 0.6 mm.

[0023] (3) The bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers are respectively reinforced by air-jet needling. The air pressure of the air-jet needling method is 0.4 MPa to 1.0 MPa, the pore diameter of the air outlet of the jet needle is 1 mm, the jet speed is between 60 m / s and 110 m / s, the distance between the air-jet needles is between 10 mm and 12 mm, and the air-jet frequency is 150 times per minute.

[0024] (4) The bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers that have been reinforced by air-jet needling are each subjected to three steps of treatment: the first step is to wash with distilled water for 6 minutes, the second step is to sterilize in high-pressure steam at 121 °C and 103.4 KPa for 20 minutes, and the third step is to dry in an oven at 60 °C for 2 hours.

[0025] (5) Configure Acinetobacter junii for denitrifying polyphosphorus into a bacterial suspension with a concentration of 10 5 CFU / mL to 10 7 CFU / mL. Immerse the bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers into the prepared bacterial suspension respectively, and the soaking time is 24 hours for all. After the soaking is over, the microbial film thicknesses on the bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers are different. The microbial film thickness on the first layer of bamboo fiber and acrylic fiber composite layer is 1.5 mm, the microbial film thickness on the third layer of bamboo fiber and acrylic fiber composite layer is 1.3 mm, and the microbial film thickness on the fifth layer of bamboo fiber and acrylic fiber composite layer is 1.1 mm; from the different microbial film thicknesses on the bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers, the denitrification and phosphorus removal rates of the bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers can be obtained. The denitrification and phosphorus removal rate of the first layer of bamboo fiber and acrylic fiber composite layer is 99.6%, the denitrification and phosphorus removal rate of the third layer of bamboo fiber and acrylic fiber composite layer is 99.4%, and the denitrification and phosphorus removal rate of the fifth layer of bamboo fiber and acrylic fiber composite layer is 99.0%.

[0026] (6) The bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers after film formation, the second ethylene-vinyl acetate copolymer layer, and the fourth hydrophilic polyurethane layer are stacked from top to bottom in the following order: the first layer is the bamboo fiber and acrylic fiber composite layer, the second layer is the ethylene-vinyl acetate copolymer layer, the third layer is the bamboo fiber and acrylic fiber composite layer, the fourth layer is the hydrophilic polyurethane layer, and the fifth layer is the bamboo fiber and acrylic fiber composite layer. They are reinforced by a method of first air-needling and then water-needling. The water jet pressure of the water-needling method is 70 bar to 165 bar, the diameter of the water jet holes is 0.1 mm to 0.4 mm, the water-needling distance is between 6 mm and 9 mm, and the water-needling frequency is 300 times per minute; the air pressure of the air-needling method is 0.4 MPa to 0.6 MPa, the diameter of the air outlet holes of the air-jet needles is 1 mm, the air-jet speed is between 60 m / s and 110 m / s, the distance between the air-needling heads is between 10 mm and 12 mm, and the air-needling frequency is 150 times per minute.

[0027] (7) The composite biological carrier in this patent after reinforcement is placed in urban sewage. The dissolved oxygen in the anaerobic section of the urban sewage needs to be strictly controlled below 0.2 mg / L, the dissolved oxygen concentration in the anoxic section needs to be strictly controlled below 0.5 mg / L, and the pH values in both the anaerobic section and the anoxic section need to be controlled between 7 and 8; after 48 hours, the nitrogen and phosphorus removal rate of the composite biological carrier in this patent is 99.0%.

[0028] Example 2

[0029] (1) Take four materials: bamboo fiber, acrylic fiber, hydrophilic polyurethane, and ethylene-vinyl acetate copolymer for 5-layer lamination treatment. Stacked from top to bottom, they are: the first layer is the bamboo fiber and acrylic fiber composite layer, the second layer is the ethylene-vinyl acetate copolymer layer, the third layer is the bamboo fiber and acrylic fiber composite layer, the fourth layer is the hydrophilic polyurethane layer, and the fifth layer is the bamboo fiber and acrylic fiber composite layer.

[0030] (2) In the first-layer bamboo fiber and acrylic fiber composite layer, the thickness of the bamboo fiber is 2.9 mm and the thickness of the acrylic fiber is 0.8 mm; the thickness of the second-layer ethylene-vinyl acetate copolymer layer is 2.4 mm; in the third-layer bamboo fiber and acrylic fiber composite layer, the thickness of the bamboo fiber is 2.8 mm and the thickness of the acrylic fiber is 0.7 mm; the thickness of the fourth-layer hydrophilic polyurethane layer is 2.4 mm; in the fifth-layer bamboo fiber and acrylic fiber composite layer, the thickness of the bamboo fiber is 2.7 mm and the thickness of the acrylic fiber is 0.6 mm.

[0031] (3) The bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers are respectively reinforced by air-lancing. The air-lancing pressure is 0.4 MPa to 1.0 MPa, the pore diameter of the air-jet needle outlet is 1 mm, the air-jet speed is between 60 m / s and 110 m / s, the distance between the air-lancing heads is between 10 mm and 12 mm, and the air-lancing frequency is 150 times per minute.

[0032] (4) The bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers that have been reinforced by air-lancing are each subjected to three steps of treatment: the first step is to wash with distilled water for 6 minutes, the second step is to sterilize in high-pressure steam at 121 °C and 103.4 KPa for 20 minutes, and the third step is to dry in an oven at 60 °C for 2 hours.

[0033] (5) The Acinetobacter junii for denitrifying phosphorus removal is configured into a bacterial suspension with a concentration of 10 5 CFU / mL to 10 7 CFU / mL. The bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers are respectively immersed in the prepared bacterial suspension for 24 hours. After the immersion, the microbial film thicknesses on the bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers are different. The microbial film thickness on the bamboo fiber and acrylic fiber composite layer of the first layer is 1.51 mm, the microbial film thickness on the bamboo fiber and acrylic fiber composite layer of the third layer is 1.31 mm, and the microbial film thickness on the bamboo fiber and acrylic fiber composite layer of the fifth layer is 1.12 mm; from the different microbial film thicknesses on the bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers, the denitrification and phosphorus removal rates of the bamboo fiber and acrylic fiber composite layers of the first, third, and fifth layers can be obtained. The denitrification and phosphorus removal rate of the bamboo fiber and acrylic fiber composite layer of the first layer is 99.7%, the denitrification and phosphorus removal rate of the bamboo fiber and acrylic fiber composite layer of the third layer is 99.5%, and the denitrification and phosphorus removal rate of the bamboo fiber and acrylic fiber composite layer of the fifth layer is 99.2%.

[0034] (6) The bamboo fiber acrylic fiber composite layers of the first, third, and fifth layers after film formation, the second ethylene-vinyl acetate copolymer layer, and the fourth hydrophilic polyurethane layer are arranged from top to bottom in the following order: the first layer is the bamboo fiber and acrylic fiber composite layer, the second layer is the ethylene-vinyl acetate copolymer layer, the third layer is the bamboo fiber and acrylic fiber composite layer, the fourth layer is the hydrophilic polyurethane layer, and the fifth layer is the bamboo fiber and acrylic fiber composite layer. First, needling is carried out by air and then by water. The water jet pressure of the water needling method is 70 bar to 165 bar, the diameter of the water jet hole is 0.1 mm to 0.4 mm, the water needling distance is between 6 mm and 9 mm, and the water needling frequency is 300 times / minute; the air pressure of the air needling method is 0.4 MPa to 0.6 MPa, the pore diameter of the air outlet of the air jet needle is 1 mm, the air jet speed is between 60 m / s and 110 m / s, the distance between the air needling heads is between 10 mm and 12 mm, and the air needling frequency is 150 times / minute.

[0035] (7) Put the composite biological carrier in this patent after reinforcement into urban sewage. The dissolved oxygen in the anaerobic section of the urban sewage needs to be strictly controlled below 0.2 mg / L, and the dissolved oxygen concentration in the anoxic section needs to be strictly controlled below 0.5 mg / L. The pH values of both the anaerobic section and the anoxic section need to be controlled between 7 and 8; after 48 hours, the nitrogen and phosphorus removal rate of the composite biological carrier in this patent is 99.1%.

Claims

1. A composite biological carrier for urban sewage treatment, characterized in that: Step 1: The first, third and fifth layers of bamboo fiber and acrylic fiber composite layers are reinforced by air puncture method respectively, and bamboo fiber and acrylic fiber composite layers of the same length and width and different thickness are respectively made, wherein the air pressure during the air puncture method is 0.4MPa to 1.0MPa, the air outlet aperture of the air jet needle is 1mm, the air jet speed is between 60m / s and 110m / s, the air puncture head spacing is between 10mm and 12mm, and the air puncture frequency is 150 times / minute; wherein the air pressure P of the air puncture method is 0.4MPa to 1.0MPa, the air outlet aperture of the air jet needle is 1mm, the air jet speed is between 60m / s and 110m / s, the air puncture head spacing is between 10mm and 12mm, and the air puncture frequency is 150 times / minute. a , in KPa and temperature T, in °C, satisfy a specific functional relationship: P a =|-3T+200|, 200≤T≤400; the jet velocity ν of the air puncture method, in units of m / s and the time t, in units of s, satisfy a specific functional relationship: ν=|-70t+10|, 1<t<3; Step 2: The first, third and fifth layers of bamboo fiber and acrylic fiber composite layers reinforced in step 1 are respectively subjected to three-step treatment: the first step is distilled water washing, the second step is high-pressure steam sterilization, and the third step is oven drying; wherein the distilled water washing time is 6 minutes; The temperature of the high-pressure steam sterilizer is set to 121°C, the operating pressure is 103.4KPa, the sterilization time is 20 minutes, and the high-pressure steam sterilizer is taken out after depressurization and cooling; the oven temperature is set to 60°C, and the drying time is set to 2 hours; Step 3: Use the denitrifying polyphosphate-accumulating Acinetobacter junae to perform static immersion inoculation biofilm treatment on the first, third, and fifth layers of the bamboo fiber acrylic fiber composite layer treated in step 2: configure the denitrifying polyphosphate-accumulating Acinetobacter junae to a concentration of 10 5 CFU / mL to 10 7 CFU / mL of bacterial suspension, immersing the first, third and fifth bamboo fiber acrylic fiber composite layers in the prepared bacterial suspension respectively, and the immersion time is 24 hours. After the immersion, three microbial films of different thicknesses can be obtained on the first, third and fifth bamboo fiber acrylic fiber composite layers; Step 4: Put the first, third and fifth bamboo fiber acrylic fiber composite layers after the biofilm formation in step 3 into urban sewage, and after 48 hours, the first, third and fifth bamboo fiber acrylic fiber composite layers have different denitrification and phosphorus removal rates for urban sewage. , where the denitrification and phosphorus removal rates η1, η3, and η5 of the first, third, and fifth bamboo fiber acrylic fiber composite layers for urban sewage are respectively related to the microbial film thickness h1 on the first bamboo fiber acrylic fiber composite layer, the unit is mm, the microbial film thickness h3 on the third bamboo fiber acrylic fiber composite layer, the unit is mm, and the microbial film thickness h5 on the fifth bamboo fiber acrylic fiber composite layer, the unit is mm, and satisfy the specific functional relationship: η1=0.1×(h1+2)+0.646, 1.5≤h1<2.0; η3=0.15×(1+h3 )+0.649, 1.3≤h3<1.5; η5=0.1×h5+0.88, 1.0≤h5<1.3; Step 5: The first, third and fifth bamboo fiber acrylic fiber composite layers after the film hanging in step 3, the ethylene-vinyl acetate copolymer layer of a certain thickness and the hydrophilic polyurethane layer of a certain thickness are arranged in the following order from top to bottom: the first layer is the bamboo fiber and acrylic fiber composite layer, the second layer is the ethylene-vinyl acetate copolymer layer, the third layer is the bamboo fiber and acrylic fiber composite layer, the fourth layer is the hydrophilic polyurethane layer, and the fifth layer is the bamboo The order of the fiber and acrylic fiber composite layer is reinforced by a combination of water spunlace and air spunlace, wherein the water jet pressure is 70 bar to 165 bar, the water jet hole diameter is 0.1 mm to 0.4 mm, the water spunlace distance is between 6 mm and 9 mm, and the water spunlace frequency is 300 times / minute; the air pressure is 0.4 MPa to 0.6 MPa, the air outlet hole diameter of the air jet needle is 1 mm, the air jet speed is between 60 m / s and 110 m / s, the air spunlace head spacing is between 10 mm and 12 mm, and the air spunlace frequency is 150 times / minute; wherein the water jet pressure P of the water spunlace method is w , in bar, and the water jet velocity ω, in m / s, satisfy the specific functional relationship: P w =(ω+2) 2 +21, 5≤ω≤10; Step 6: Place the composite biological carrier in this patent reinforced in step 5 into urban sewage for 48 hours to obtain the denitrification and phosphorus removal rate of the composite biological carrier in this patent. The denitrification and phosphorus removal effect of the composite biological carrier in this patent on urban sewage is judged by the denitrification and phosphorus removal rate formula of the composite biological carrier: Where: γ is the denitrification and phosphorus removal rate of the composite biological carrier in this patent, which is used to judge the denitrification and phosphorus removal effect of the composite biological carrier in this patent on urban sewage; h1, h2, h3, h4, and h5 are respectively the thickness of the microbial film on the first layer of bamboo fiber and acrylic fiber composite layer, with a value range of 1.5≤h1<2.0, the thickness of the second layer of ethylene-vinyl acetate copolymer layer, with a value range of 2.0≤h2<2.5, the thickness of the microbial film on the third layer of bamboo fiber and acrylic fiber composite layer, with a value range of 1.3≤h3<1.5, the thickness of the fourth layer of hydrophilic polyurethane layer, with a value range of 2.0≤h4<2.5, and the thickness of the fifth layer of microbial film on the bamboo fiber and acrylic fiber composite layer, with a value range of 1.0≤h5<1.3; all units are mm; 0.3, 0.15, 0.25, 0.1, and 0.2 are weight factors for the thickness of the microbial film on the first layer of bamboo fiber and acrylic fiber composite layer, the second layer of ethylene-vinyl acetate copolymer layer, the third layer of bamboo fiber and acrylic fiber composite layer, the fourth layer of hydrophilic polyurethane layer, and the fifth layer of bamboo fiber and acrylic fiber composite layer, respectively. Z1, Z3, and Z5 are respectively the thickness of the first layer of bamboo fiber and acrylic fiber composite layer, with a value range of 3.6≤Z1<4.0, the thickness of the third layer of bamboo fiber and acrylic fiber composite layer, with a value range of 3.4≤Z3<3.6, and the thickness of the fifth layer of bamboo fiber and acrylic fiber composite layer, with a value range of 3.2≤Z5<3.4; all units are mm; P a is the air pressure of the air puncture method, the unit is KPa; P w is the water jet pressure of the hydroentanglement method, in bar; ν is the jet velocity of the airentanglement method, in m / s.

2. A composite biological carrier for urban sewage treatment according to claim 1, characterized in that: The thickness of the bamboo fiber in the first, third and fifth bamboo fiber acrylic fiber composite layers is determined by the air pressure of the air stab method, the water jet pressure of the water stab method and the jet speed of the air stab method and all satisfy a specific relationship: m1=0.5P a +0.2P w +0.3ν Where: P a is the air pressure of the air puncture method, the unit is KPa; P w is the water jet pressure of the hydroentanglement method, in bar; ν is the jet velocity of the air entanglement method, in m / s; m1 can be the bamboo fiber thickness in the first layer of bamboo fiber acrylic fiber composite layer, can be the bamboo fiber thickness in the third layer of bamboo fiber acrylic fiber composite layer, or can be the bamboo fiber thickness in the fifth layer of bamboo fiber acrylic fiber composite layer, all in mm; 0.5 is the weight factor of the air pressure of the air entanglement method to the bamboo fiber thickness; 0.2 is the weight factor of the water jet pressure of the hydroentanglement method to the bamboo fiber thickness; 0.3 is the weight factor of the jet velocity of the air entanglement method to the bamboo fiber thickness; The thickness of the acrylic fiber in the first, third and fifth bamboo fiber acrylic fiber composite layers is determined by the air pressure of the air stab method, the water jet pressure of the water stab method and the jet speed of the air stab method and all satisfy a specific relationship: m2=0.3P a +0.2P w +0.5ν Where: P a is the air pressure of the air puncture method, the unit is KPa; P w is the water jet pressure of the hydroentanglement method, and the unit is bar; ν is the jet speed of the air entanglement method, and the unit is m / s; m2 can be the acrylic fiber thickness in the first layer of bamboo fiber acrylic fiber composite layer, can be the acrylic fiber thickness in the third layer of bamboo fiber acrylic fiber composite layer, or can be the acrylic fiber thickness in the fifth layer of bamboo fiber acrylic fiber composite layer, all in mm; 0.3 is the weight factor of the air pressure of the air entanglement method to the bamboo fiber thickness; 0.2 is the weight factor of the water jet pressure of the hydroentanglement method to the bamboo fiber thickness; 0.5 is the weight factor of the jet speed of the air entanglement method to the bamboo fiber thickness.

3. The composite biological carrier for urban sewage treatment according to claim 1, characterized in that: The water jet velocity and the water jet hole diameter satisfy a specific functional relationship: ω=-2.4g+3.3, wherein ω represents the water jet velocity in m / s, g represents the water jet hole diameter in mm, and the value range of the water jet hole diameter is 0.1≤g≤0.

4.

4. The composite biological carrier for urban sewage treatment according to claim 1, characterized in that: The thickness of the microbial film on the first, third and fifth bamboo fiber acrylic fiber composite layers are all related to the concentration of the bacterial suspension prepared by denitrifying polyphosphate-accumulating Acinetobacter junae, the thickness of the first bamboo fiber and acrylic fiber composite layer, the thickness of the second ethylene-vinyl acetate copolymer layer, the thickness of the third bamboo fiber and acrylic fiber composite layer, the thickness of the fourth hydrophilic polyurethane layer, the thickness of the fifth bamboo fiber and acrylic fiber composite layer, the dissolved oxygen concentration of the anaerobic section, the dissolved oxygen concentration of the anoxic section, the pH of the anaerobic section, and the pH of the anaerobic section, and satisfy a specific relationship: Wherein: h1, h2, h3, h4, h5 are respectively the thickness of the microbial film on the first layer of bamboo fiber and acrylic fiber composite layer, the value range is 1.5≤h1<2.0, the thickness of the second layer of ethylene-vinyl acetate copolymer layer, the value range is 2.0≤h2<2.5, the thickness of the microbial film on the third layer of bamboo fiber and acrylic fiber composite layer, the value range is 1.3≤h3<1.5, the thickness of the fourth layer of hydrophilic polyurethane layer, the value range is 2.0≤h4<2.5, the fifth layer is the thickness of the microbial film on the bamboo fiber and acrylic fiber composite layer, the value range is 1.0≤h5<1.3; the unit is mm; Z1, Z3, and Z5 are respectively the thickness of the first layer of bamboo fiber and acrylic fiber composite layer, with a value range of 3.6≤Z1<4, the thickness of the third layer of bamboo fiber and acrylic fiber composite layer, with a value range of 3.4≤Z3<3.6, and the thickness of the fifth layer of bamboo fiber and acrylic fiber composite layer, with a value range of 3.2≤Z5<3.4; all units are mm; c is the concentration of the bacterial suspension prepared by denitrifying phosphorus-accumulating Acinetobacter junae, and the value range is 10 5 ≤c≤10 7 , the unit is CFU / mL; x1 represents the dissolved oxygen concentration in the anaerobic section, with a value range of 0<x1<0.2, and the unit is mg / L; x2 represents the dissolved oxygen concentration in the anoxic zone, with a value range of 0<x2<0.5 and a unit of mg / L; p1 is the pH of the anaerobic section, and its value range is 7<p1<8; p2 is the pH of the anoxic phase, and its value range is 7<p2<8; 0.3, 0.25, 0.2, 0.15, and 0.1 are the weight factors of the thickness of the first, third, and fifth bamboo fiber acrylic fiber composite layers, the weight factors of the thickness of the second ethylene-vinyl acetate copolymer layer and the fourth hydrophilic polyurethane layer, the weight factor of the concentration of the bacterial suspension configured with denitrifying polyphosphate Acinetobacter junii, the weight factor of dissolved oxygen in urban sewage, and the weight factor of pH in urban sewage.

5. The composite biological carrier for urban sewage treatment according to claim 1, characterized in that: The thickness of the second layer of ethylene-vinyl acetate copolymer h2, in mm, is related to the air pressure P of the air puncture method. a , unit is KPa, water jet pressure P of hydroentanglement w , in bar, and the jet velocity ν of the air piercing method, in m / s, satisfies a specific functional relationship: Wherein: 0.5 is the weight factor of the total pressure composed of the air pressure of the air spunlace method and the water jet pressure of the water spunlace method on the thickness of the ethylene-vinyl acetate copolymer layer; 0.2 is the weight factor of the water spunlace method on the thickness of the ethylene-vinyl acetate copolymer layer; 0.3 is the weight factor of the air spunlace method on the thickness of the ethylene-vinyl acetate copolymer layer; The thickness of the fourth hydrophilic polyurethane layer h4, in mm, is related to the air pressure P of the air puncture method. a , unit is KPa, water jet pressure P of hydroentanglement w , in bar, and the jet velocity ν of the air piercing method, in m / s, satisfies a specific functional relationship: In the formula: 0.3 is the weight factor of the total pressure composed of the air pressure of the air spunlace method and the water jet pressure of the water spunlace method on the thickness of the hydrophilic polyurethane layer; 0.2 is the weight factor of the water spunlace method on the thickness of the hydrophilic polyurethane layer; 0.5 is the weight factor of the air spunlace method on the thickness of the hydrophilic polyurethane layer.

6. The composite biological carrier for urban sewage treatment according to claim 1, characterized in that: The water-entanglement and air-entanglement combined method adopts the order of air-entanglement first and water-entanglement second and satisfies the specific functional relationship: γ = e d +P w 2 +4.5P a , where P a Indicates the air pressure of the air puncture method, the unit is KPa, P w represents the water jet pressure of the hydroentanglement method, the unit is bar, d represents the order of air entanglement first and then hydroentanglement, γ represents the nitrogen and phosphorus removal rate of the composite biological carrier in this patent, where 0.3<P a ≤0.7,50≤P w <100, the values ​​of d are 1 and 0, d taking 1 represents air puncture first and then water puncture, and d taking 0 represents water puncture first and then air puncture; and it can be concluded from the formula that the order of air puncture first and then water puncture has an exponentially increasing effect on the nitrogen and phosphorus removal rate of the composite biological carrier in this patent.

7. The composite biological carrier for urban sewage treatment according to claim 1, characterized in that: The dissolved oxygen in the anaerobic section of the urban sewage needs to be strictly controlled below 0.2 mg / L, and the dissolved oxygen concentration in the anoxic section needs to be strictly controlled below 0.5 mg / L, and the dissolved oxygen concentrations in the anaerobic section and the anoxic section have a specific relationship with the denitrification and phosphorus removal rate γ of the composite biological carrier in this patent: 0<x1<0.2, 0<x2<0.5; wherein x1 represents the dissolved oxygen concentration of the anaerobic section, the unit is mg / L, and x2 represents the dissolved oxygen concentration of the anoxic section, the unit is mg / L; from the formula, it can be concluded that when the dissolved oxygen concentration of the anaerobic section is 0.2 mg / L and the dissolved oxygen concentration of the anoxic section is 0.5 mg / L, the denitrification and phosphorus removal rate γ of the composite biological carrier in this patent reaches the minimum value; and when the dissolved oxygen concentration of the anaerobic section is 0.1 mg / L and the dissolved oxygen concentration of the anoxic section is 0.4 mg / L, the denitrification and phosphorus removal rate γ of the composite biological carrier in this patent reaches the maximum value; the pH of the anaerobic section and the anoxic section both need to be controlled between 7 and 8, and pH<7 or pH>8 will destroy the cell structure of the microorganisms on the bamboo fiber acrylic fiber composite layer.

8. The composite biological carrier for urban sewage treatment according to claim 1, characterized in that: The denitrification and phosphorus removal rates of the first, third and fifth bamboo fiber acrylic fiber composite layers for urban sewage and the denitrification and phosphorus removal rates of the composite biological carrier in this patent for urban sewage satisfy a specific relationship: γ=min(γ0) Where: γ is the nitrogen and phosphorus removal rate of the composite biological carrier in this patent for urban sewage; γ0 represents three values, which are the denitrification and phosphorus removal rates of the first layer of bamboo fiber and acrylic fiber composite layer for urban sewage, the denitrification and phosphorus removal rates of the third layer of bamboo fiber and acrylic fiber composite layer for urban sewage, and the denitrification and phosphorus removal rates of the fifth layer of bamboo fiber and acrylic fiber composite layer for urban sewage; η1 is the nitrogen and phosphorus removal rate of the first layer of bamboo fiber and acrylic fiber composite layer on urban sewage; η3 is the nitrogen and phosphorus removal rate of the third layer of bamboo fiber and acrylic fiber composite layer on urban sewage; η5 is the nitrogen and phosphorus removal rate of the fifth layer of bamboo fiber and acrylic fiber composite layer for urban sewage.

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