Microbial carrier with sewage treatment function and application thereof

Abstract

The invention provides a microbial carrier with a sewage treatment function and application thereof, and belongs to the technical field of fracturing fluid. Comprising a large ball body, a middle ball body, a small ball body, polyurethane filler and immobilized functional bacteria, the large ball body is the outermost layer, and the middle ball body is located in the large ball body, fixed to a rotating shaft of the large ball body and rotates around the rotating shaft by 360 degrees; the large ball and the middle ball are concentric; the rotating shaft of the large ball is coaxial with the top hole of the middle ball; and the small ball and the polyurethane filler are positioned in the middle ball. A novel functional microbial carrier is designed, a microbial technology, a biological carrier technology and a signal molecule regulation and control technology are combined, the defects of an existing microbial carrier are overcome, the problem that a biological membrane is difficult to form is solved, the biochemical reaction capacity in the sewage treatment process is remarkably improved, and the sewage treatment efficiency is improved. The microbial diversity and the sewage treatment efficiency are improved, and the starting time of the sewage treatment reactor is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of fracturing fluid, and in particular to a sewage treatment functional microbial carrier and application thereof. Background Art

[0002] Mud film symbiosis is an efficient and stable sewage treatment method with the characteristics of small amount of sludge, strong resistance to shock load, good adaptability to changes in wastewater quality and water volume, and simple operation and management. Microbial carriers are key components in the mud film symbiosis treatment process and are widely used in water treatment. They are the habitat and growth carrier of microorganisms. The performance of microorganisms is directly related to the difficulty of biofilm formation, the type and quantity of microorganisms, and thus directly affects the sewage treatment efficiency.

[0003] The selection and colonization of microorganisms are the key to the startup and stable operation of sewage treatment reactors. The startup process of traditional sewage treatment reactors is too dependent on the enrichment of indigenous microorganisms, but the enrichment process is slow and leads to slow startup of water treatment equipment.

[0004] The current microbial carriers themselves do not participate in the biochemical reaction of water treatment, but only increase the specific surface area, increase the porosity, further improve the hydraulic conditions, increase the hydraulic retention time, interception capacity and nutrient supply, and ultimately improve the microbial proliferation and water treatment capacity. However, the existing carriers have the following defects: (1) The assembly method is single, and the microbial filler must be loaded into the carrier in advance, and it cannot be assembled by post-loading; (2) The gap between the separators in the suspended carrier is small, which is not conducive to the passage of sewage and its full contact with the carrier; (3) The current microbial carriers have the problem of slow biofilm formation speed and long time; (4) The lack of introduction of functional strains for sewage treatment and excessive reliance on indigenous microorganisms resulted in a single community structure, poor sewage treatment effects, and a long reactor startup time. Summary of the invention

[0005] The purpose of the present invention is to solve the problems existing in the existing microbial carriers, and solve the problems of slow biofilm growth rate, poor impact resistance and long startup time in sewage treatment reactors. The problem of slow microbial colonization and single microbial community structure in sewage treatment equipment is solved. The present invention has more abundant filler assembly forms, which solves the problem that fillers cannot be loaded into the carrier by post-loading; a new type of microbial carrier with large specific surface area, good microbial attachment performance, long service life, uniform biofilm distribution and resistance to water flow impact is proposed. The carrier can intercept suspended matter and provide an attachment site for microbial flora. At the same time, combined with internal functional bacteria, it can promote the production of biofilms, improve the diversity and stability of microbial communities, and increase the relative abundance of functional bacteria such as quorum sensing, nitrification and denitrification, thereby improving the removal efficiency of different pollutants in sewage and shortening the startup time of sewage treatment reactors.

[0006] The technical solution of the present invention is achieved in this way: The present invention provides a functional microbial carrier for sewage treatment, comprising three different spheres of large, medium and small sizes, as well as polyurethane fillers and immobilized functional bacteria, wherein the large sphere is the outermost layer, the medium sphere is located inside the large sphere and is fixed on the rotating shaft of the large sphere and rotates 360° around the rotating shaft; the large sphere is concentric with the medium sphere; the rotating shaft of the large sphere is coaxial with the top hole of the medium sphere; the small sphere and the polyurethane filler are located inside the medium sphere.

[0007] The diameter of the large ball is 7-12 cm, the diameter of the medium ball is 4-8 cm, and the diameter of the small ball is 1-3 cm.

[0008] The three spheres can be made of materials such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and polyurethane (PU).

[0009] The polyurethane filler is close to a rectangular parallelepiped in shape, with a side length of 1-2 cm, a pore size of 4-6 ppi, and a density of 0.4-0.6 g / cm 3 .

[0010] The microbial carrier of the present invention comprises a basic framework composed of three different spheres, large, medium and small, a polyurethane filler filled inside the medium sphere and a functional bacterial composition filled inside the small sphere; wherein both the large sphere and the medium sphere are frame structures formed by crisscrossing dividing strips, and can be opened and installed in half, and the small sphere is an internal hollow porous structure. When used, the functional bacterial composition is added to the inside of the small sphere and loaded into the medium sphere together with the polyurethane filler. The medium sphere is fixed by the rotating shaft protruding inward from the large sphere and can rotate 360° along the center line of the shaft, and the large sphere is the outermost layer. The functional bacteria inside the microbial carrier can grow and reproduce rapidly from the inside to the outside, promote the secretion of extracellular polymers and the formation of biofilms, and increase the diversity of microbial communities, while increasing the relative abundance of functional microorganisms such as quorum sensing, nitrification and denitrification, thereby improving the removal effect of different pollutants in sewage. This method not only improves the diversity and stability of the microbial community, but also promotes the treatment efficiency of the integrated sewage treatment equipment.

[0011] Specifically, the big ball is made of two completely mirror-symmetrical hemispheres that are aligned with each other, rotated 90 degrees, and pressed downward. A hollow shaft is provided on the top of each hemisphere, and a small rib that can be pressed open is provided at the bottom of the shaft. The small ball and polyurethane filler can be loaded through this hollow shaft. When the pressure is released, the rib can rebound and reduce the gap in the hole to prevent the small ball and polyurethane filler from falling out; each hemisphere is composed of criss-crossing separators, and meshes are formed between the separators; a circle of reinforcement rings is set at the maximum diameter of each hemisphere, and a barb-shaped structure that interlocks the two hemispheres is provided inside the reinforcement ring.

[0012] The middle ball is made of two completely mirror-symmetrical hemispheres that are aligned with each other, rotated 90°, and pressed down. Each hemisphere has a hole on the top that matches the large ball's rotation axis. During assembly, this hole is set on the large ball's rotation axis and can rotate 360° around the rotation axis. When the large ball and the middle ball are assembled, the small ball and polyurethane filler can be installed into the middle ball through the hollow rotation axis of the large ball. Each hemisphere is composed of criss-crossing separators, and meshes are formed between the separators. A circle of reinforcement rings is set at the maximum diameter of each hemisphere, and a barb-shaped structure that interlocks the two hemispheres is set inside the reinforcement ring.

[0013] The ball is formed by docking two completely mirror-symmetrical hollow hemispheres. Each hemisphere has a hole at the top, and small ribs that can be pressed open are arranged around the hole. The immobilized bacterial composition can fall into the ball through the gap formed by pressing the ribs. When the pressure is released, the ribs can rebound and reduce the gap in the hole to prevent the immobilized bacterial composition from flowing out. The top of each hemisphere is the thinnest, and the maximum radius is the thickest. In addition to the top, each hemisphere is equipped with evenly arranged small holes to form a spherical mesh porous structure. The aperture of these small holes is smaller than that of the immobilized bacterial composition, which can facilitate the entry and exit of sewage and air, and wrap the immobilized bacterial composition.

[0014] The functional bacteria have quorum sensing, nitrification or denitrification functions, and are composed of one or more of Bacillus, Pseudomonas, Acinetobacter, Xanthomonas, Comamonas, Nitrosomonas, and Acidovorax.

[0015] Specifically, Pseudomonas can secrete signal molecules to improve the pollutant removal effect through quorum sensing; Bacillus, Pseudomonas and Acinetobacter are heterotrophic nitrifying bacteria that can efficiently remove COD and ammonia nitrogen; Xanthomonas, Comamonas and Acidovorax are heterotrophic denitrifying bacteria that can efficiently remove pollutants such as COD, nitrate nitrogen and total nitrogen in sewage; Nitrosomonas is a chemoautotrophic bacterium that can efficiently remove ammonia nitrogen in sewage in the absence of a carbon source.

[0016] Furthermore, the immobilized functional bacteria are immobilized by polyvinyl alcohol-sodium alginate embedding method, and a single bacterial species is immobilized in the same microsphere, or a composite bacterial species is immobilized in the same microsphere to prepare an immobilized bacterial composition with different functions.

[0017] Furthermore, after the immobilized bacterial composition is mixed in different proportions and the large ball and the medium ball are assembled, the small ball and the polyurethane filler are loaded into the inside of the medium ball through the hollow rotating shaft of the large ball to obtain a multi-ball suspended microbial carrier containing bacterial compositions with different functions. The assembled combined carrier structure is as follows: the large ball is the outermost layer, the medium ball is located inside the large ball and is fixed on the rotating shaft of the large ball and can rotate 360 ​​degrees around the rotating shaft; the large ball is concentric with the medium ball; the rotating shaft of the large ball is coaxial with the top hole of the medium ball; the small ball and the polyurethane filler are located inside the medium ball.

[0018] Furthermore, the above-mentioned multi-spherical suspended microbial carrier was added to the laboratory A / O sewage treatment reactor. The removal rates of COD, ammonia nitrogen and total nitrogen by the microbial carrier of the present invention were higher than those of the commercially available double-spherical carrier, and the stabilization time of the effluent was shortened, which had a better removal effect on COD, ammonia nitrogen and total nitrogen.

[0019] Furthermore, adding the microbial carrier of the present invention into a laboratory A / O sewage treatment reactor can significantly increase the content of protein and polysaccharide, thereby increasing the content of extracellular polymers.

[0020] Furthermore, adding the microbial carrier of the present invention into a laboratory A / O sewage treatment reactor can significantly improve the diversity of the bacterial community structure in the biofilm, while increasing the relative abundance of different sewage treatment functional strains such as quorum sensing bacteria (Pseudomonas), heterotrophic nitrifying bacteria (Bacillus, Pseudomonas and Acinetobacter), heterotrophic denitrifying bacteria (Xanthobacterium, Comamonas and Acidovorax) and chemoautotrophic bacteria (Nitrosomonas) in the microbial carrier.

[0021] Furthermore, the microbial carrier of the present invention is added into the Panda-Box-500 bioreactor for actual sewage treatment. The microbial carrier of the present invention can improve the removal effect of COD, ammonia nitrogen and total nitrogen in sewage, the effluent is stably up to the standard, and the time for effluent stabilization is shortened, and the removal effect of COD, ammonia nitrogen and total nitrogen is better.

[0022] Furthermore, when the microbial carrier of the present invention is added into the Panda-Box-500 bioreactor for actual sewage treatment, the biofilm amount per unit filler of the microbial carrier of the present invention is significantly higher than that of the commercially available double-ball microbial carrier, and has a better biofilm effect.

[0023] The present invention has the following beneficial effects: In order to overcome the shortcomings of the prior art, the present invention provides a functional microbial carrier for sewage treatment. The carrier is composed of a basic structure consisting of three different spheres, large, medium and small, a polyurethane filler filled inside the medium sphere and a functional bacterial composition filled inside the small sphere. The functional bacteria can significantly improve the adhesion of microorganisms and increase the biomass in the biofilm by releasing quorum sensing signal molecules. In addition, these functional bacteria also have the functions of organic matter degradation, nitrification and denitrification, which can quickly realize the rapid startup of the sewage treatment system and enhance the treatment efficiency of the sewage treatment equipment.

[0024] The multi-spherical suspended microbial carrier of the present invention adopts a three-layer spherical structure, a polyurethane filler is filled in the middle ball, and an immobilized bacterial composition is loaded in the small ball. This optimized structural configuration provides more attachment sites for microorganisms, improves the types and quantity of microorganisms, promotes the mass transfer efficiency between gas-liquid-solid three-phase substances, and accelerates the removal efficiency of pollutants in water. In addition, the microbial carrier of the present invention can be suspended and flowed in a sewage treatment pool, the middle ball and the large ball can rotate in opposite directions, and the small ball and the polyurethane filler can roll inside the middle ball, so that sewage, air and the biofilm grown on the surface of the filler are fully contacted, which can effectively intercept the suspended microorganisms, promote the rapid formation of the biofilm, and also can keep the microorganisms in the biofilm active. As the microorganisms continue to attach and grow on the floating ball filler, the aerobic zone, the anoxic zone, and the anaerobic zone formed in sequence from the outside to the inside of the microbial carrier can simultaneously carry out aerobic, anoxic and anaerobic biochemical reactions, which is conducive to strengthening the nitrification reaction and denitrification reaction, and improving the biological denitrification effect. The functional water treatment bacteria fixed inside have functions such as quorum sensing, nitrification and denitrification, which can promote the production of extracellular polymers and the formation of biofilms, promote the growth and colonization of functional microorganisms, improve the diversity and stability of microbial communities, and increase the relative abundance of functional bacteria themselves in biofilms, ultimately improving the treatment efficiency of sewage treatment equipment.

[0025] In summary, the present invention designs a new type of functional microbial carrier, which combines microbial technology, biological carrier technology and signal molecule regulation technology. It not only makes up for the shortcomings of existing microbial carriers and solves the problem of difficulty in biofilm formation, but also significantly improves the biochemical reaction capacity of the sewage treatment process, improves microbial diversity and sewage treatment efficiency, and shortens the startup time of the sewage treatment reactor.

[0026] Compared with the prior art, the present invention has the following beneficial effects: (1) The novel functional microbial carrier designed in the present invention can realize rapid biofilm formation on the microbial carrier.

[0027] (2) The novel functional microbial carrier designed by the present invention can significantly enhance the capacity of biochemical reactions related to sewage treatment and improve the removal effect of pollutants.

[0028] (3) The novel functional microbial carrier designed by the present invention can improve the diversity of microbial communities and increase the relative abundance of water treatment functional bacteria in biofilms.

[0029] (4) The novel functional microbial carrier designed by the present invention can be assembled by post-loading, which has a richer assembly form. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 This is a structural diagram of the functional microbial carrier for sewage treatment; Figure 2 This is the COD removal effect diagram under different treatments; Figure 3 It is the trend diagram of COD removal rate under different treatments; Figure 4 This is the effect diagram of ammonia nitrogen removal under different treatments; Figure 5 It is the trend diagram of ammonia nitrogen removal rate under different treatments; Figure 6 This is the total nitrogen removal effect diagram under different treatments; Figure 7 It is the trend diagram of total nitrogen removal rate under different treatments; Figure 8 is a graph of the extracellular polymer content in microbial carriers; Fig. 9Figure 2 is the relative abundance diagram of bacterial genus level under different treatments; Fig.10 This is a diagram of the actual sewage treatment process; Fig.11 This is the actual sewage COD treatment effect diagram; Fig.12 This is the actual sewage ammonia nitrogen treatment effect diagram; Fig.13 This is the actual sewage total nitrogen treatment effect diagram; Fig.14 The biofilm effect diagram of different microbial carriers (a and b are the control group and the experimental group respectively); Fig.15 These are the biofilm effects of different microbial carriers. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1 Preparation of a bacterial composition containing heterotrophic nitrifying bacteria The Bacillus used in the present invention ( Bacillus )、Acinetobacter( Acinetobacter ) and Pseudomonas ( Pseudomonas ) is a heterotrophic nitrifying bacteria that can efficiently remove COD and ammonia nitrogen. In addition, Pseudomonas is also a type of quorum sensing bacteria that can secrete signal molecules hexanoyl-L-homoserine lactone (C6-HSL) and octanoyl-L-homoserine lactone (C8-HSL), promote the formation of biofilms and the secretion of extracellular polymers, and improve the treatment effect of various pollutants.

[0034] Inoculate the above heterotrophic nitrifying bacteria into 300 mL LB medium and culture at 30 °C and 150 rpm for a certain period of time. Mix the above strains in a ratio of 1:1:1. Prepare a 10% polyvinyl alcohol-1% sodium alginate mixture and heat it for a certain period of time to fully dissolve and mix it. Mix the bacterial solution and the polyvinyl alcohol-sodium alginate mixture in a ratio of 1:4 and shake well. Remove bubbles with low-power ultrasound for 10 min. Inject the above mixture into 7% H 3 BO 3 -4% CaCl 2 After cross-linking, wash the remaining cross-linking agent with clean water and then use 7.1% Na 2 SO 4After the two cross-linking steps, the residual cross-linking agent is washed off with clean water to prepare a bacterial composition containing Bacillus, Acinetobacter and Pseudomonas.

[0035] Example 2 Preparation of a bacterial composition containing heterotrophic denitrification The yellow bacterium used in the present invention ( Flavobacterium ), from Comamonas Comamonas ) and acidophilus bacteria ( Acidovorax ) is a heterotrophic denitrifying bacteria, which can efficiently remove pollutants such as COD, total nitrogen, and nitrate nitrogen in sewage. The above heterotrophic denitrifying bacteria were inoculated in 300 mL LB culture medium for culture, and the subsequent preparation method was the same as that in Example 1, and finally a bacterial composition containing heterotrophic denitrifying bacteria was obtained.

[0036] Example 3 Preparation of a bacterial composition containing Nitrosomonas The Nitrosomonas used in the present invention ( Nitrosomonas ) belongs to chemoautotrophic bacteria, which can efficiently remove ammonia nitrogen from sewage under the condition of no carbon source. It is inoculated in a Nitrosomonas culture medium (the formula is shown in Table 1) for culture, and the subsequent preparation method is the same as that in Example 1, and finally a bacterial composition containing Nitrosomonas is obtained.

[0037] Table 1 Nitrosomonas culture medium formula Nitrosomonas culture medium components Addition amount Trace element components Addition amount <![CDATA[NH 4 Cl]]> 535 mg Deionized water 975 ml <![CDATA[KH 2 AFTER 4 ]]> 54 mg 1M HCl 25 ml KCl 74 mg <![CDATA[MnSO 4 x 4 H 2 O]]> 45 mg <![CDATA[MgSO 4 x 7 H 2 O]]> 49 mg <![CDATA[H 3 BO 3 ]]> 49 mg <![CDATA[CaCl 2 x 2 H 2 O]]> 147 mg <![CDATA[ZnSO 4 x 7 H 2 O]]> 43 mg Trace Elements 1 ml <![CDATA[(NH 4 ) 6 Mon 7 O 24 x 4 H 2 O]]> 37 mg Deionized water 1000 ml <![CDATA[FeSO 4 x 7 H 2 O]]> 973 mg pH 7.8 <![CDATA[CuSO 4 x 5 H 2 O]]> 25 mg Example 4 Preparation of multispherical suspension microbial carrier containing bacterial composition like Figure 1 The bacterial compositions of Example 1, Example 2 and Example 3 were mixed in a ratio of 50 parts: 30 parts: 20 parts. Ten of the mixed bacterial compositions were pressed into the small ball structure through the holes at the top of the small ball. After the large ball and the middle ball were assembled, the small ball and the polyurethane filler (length, width and height of 2×2×1 cm) were loaded into the middle ball through the hollow shaft of the large ball to obtain a multi-ball suspended microbial carrier containing bacterial compositions with different functions.

[0038] The large ball is formed by aligning two completely mirror-symmetrical hemispheres with each other, rotating 90°, and pressing downward. A hollow rotating shaft is provided on the top of each hemisphere, and a fine rib that can be pressed open is provided at the bottom of the rotating shaft. The small balls and polyurethane fillers are installed through this hollow rotating shaft. When the pressure is released, the ribs rebound by themselves and reduce the gaps in the holes to prevent the small balls and polyurethane fillers from falling out. Each hemisphere is composed of criss-cross dividing strips, and meshes are formed between the dividing strips. A circle of reinforcement rings is set at the maximum diameter of each hemisphere, and a barb-type structure that interlocks two hemispheres is provided inside the reinforcement ring.

[0039] The middle ball is formed by aligning two completely mirror-symmetrical hemispheres, rotating 90°, and pressing them downward. A hole is provided on the top of each hemisphere to match the rotating shaft of the large ball. During assembly, the hole is sleeved on the rotating shaft of the large ball and rotates 360° around the rotating shaft. After the large ball and the middle ball are assembled, the small ball and the polyurethane filler are loaded into the middle ball through the hollow rotating shaft of the large ball. Each hemisphere is composed of criss-cross dividing strips, and meshes are formed between the dividing strips. A circle of reinforcement rings is provided at the maximum diameter of each hemisphere, and a barb-type structure that interlocks the two hemispheres is provided inside the reinforcement ring.

[0040] The small ball is formed by docking two completely mirror-symmetrical hollow hemispheres, each of which is provided with a hole at the top, and fine ribs that can be pressed open are provided around the hole, and the immobilized bacterial composition falls into the small ball through the gap formed by pressing the ribs open, and when the pressure is released, the ribs rebound and reduce the gap in the hole to prevent the immobilized bacterial composition from flowing out; each hemisphere is thinnest at the top and thickest at the maximum radius; each hemisphere, except the top, is provided with evenly arranged small holes to form a spherical mesh porous structure, and the pore size of the small holes is smaller than the immobilized bacterial composition, so that the immobilized bacterial composition is wrapped therein.

[0041] Example 5 Preparation of multispherical suspension microbial carrier containing bacterial composition The bacterial compositions of Example 1, Example 2 and Example 3 were mixed in a ratio of 30 parts: 40 parts: 30 parts. The subsequent preparation method was the same as that of Example 4, and finally a multispherical suspended microbial carrier containing bacterial compositions with different functions was obtained.

[0042] Comparative Example 1 Preparation of multi-spherical suspended microbial carrier without bacteria A bacteria-free multi-spherical suspended microbial carrier, the preparation method comprising: according to the preparation method in Example 1, LB culture medium and polyvinyl alcohol-sodium alginate mixed solution are mixed and shaken at a ratio of 1:4. The subsequent preparation method is the same as that in Example 1 to obtain a sterile polyvinyl alcohol-sodium alginate gel. Then, according to the method in Example 4, the sterile polyvinyl alcohol-sodium alginate gel, polyurethane filler and three different spheres of large, medium and small are assembled into a multi-spherical suspended microbial carrier.

[0043] Comparative Example 2 A commercially available double-sphere suspended microorganism carrier comprises two PE spheres of different sizes and a polyurethane filler in the center of the spheres.

[0044] Example 6 Sewage Treatment Reactor Operation Method The suspended microbial carriers in Example 4, Example 5, Comparative Example 1 and Comparative Example 2 were added to the laboratory A / O sewage treatment reactor. The reactor system was 100 L (a rectangular parallelepiped with a length of 50 cm, a width of 40 cm and a height of 50 cm), including an anoxic tank and an aerobic tank with a volume ratio of 1:1. The suspended microbial carriers in Example 4, Example 5, Comparative Example 1 and Comparative Example 2 were added to 5 reactors at 25% - 35% of the volume of the reactor. The hydraulic retention time of the reactor was 20 h, and the influent was simulated municipal sewage (COD concentration was in the range of 160-180 mg / L, ammonia nitrogen concentration was in the range of 40-50 mg / L, and total nitrogen concentration was in the range of 70-80 mg / L).

[0045] Example 7 Sewage treatment effects of various sewage treatment reactors The COD concentration and removal rate of the effluent from each sewage treatment reactor are as follows: Figure 2 , Figure 3 As shown, after the effluent stabilized, the average COD concentration of the four groups of reactors was lower than 40 mg / L, reaching the Class A standard for water pollutant discharge from urban sewage treatment plants. Among them, the effluent COD of Comparative Examples 1 and 2 tended to stabilize after 45 days and 51 days, respectively, and the average removal rates of COD after stabilization were 82.15% and 78.73%, respectively, indicating that the COD removal effect of the suspended microbial carrier of the present invention is better than that of the traditional commercially available double-ball biological carrier. In addition, the effluent COD of Example 4 and Example 5 tended to stabilize after 30 days and 33 days, respectively, and the average removal rates of COD after stabilization were higher than those of Comparative Example 1, which were 87.46% and 86.58%, respectively, indicating that inoculating different functional strains in the multi-ball suspended microbial carrier of the present invention can significantly improve the removal effect of COD.

[0046] The changes in the effluent ammonia nitrogen quality and removal rate of each sewage treatment reactor are as follows Figure 4 , Figure 5 As shown, after the effluent is stabilized, the concentration of ammonia nitrogen in the effluent of each group of reactors is lower than 8 mg / L, reaching the Class B standard for water pollutant discharge of urban sewage treatment plants. The effluent ammonia nitrogen of Comparative Example 1 and Comparative Example 2 tends to be stable after 48 days and 51 days, respectively, and the average removal rates of ammonia nitrogen after stabilization are 89.64% and 83.94%, respectively, indicating that the removal effect of ammonia nitrogen by the multi-spherical suspended microbial carrier of the present invention is better than that of the traditional commercially available double-spherical biological carrier. In addition, the effluent ammonia nitrogen of Example 4 and Example 5 tends to be stable after 36 days, and the average removal rates after stabilization are 93.61% and 92.71%, respectively, indicating that inoculating different functional strains in the multi-spherical suspended microbial carrier of the present invention can significantly improve the removal effect of ammonia nitrogen.

[0047] The changes in the total nitrogen water quality and removal rate of the effluent from each sewage treatment reactor are as follows Figure 6 , Figure 7 As shown. The total nitrogen in the effluent of Comparative Example 1 and Comparative Example 2 tended to be stable after 48 days and 54 days, respectively, and the average removal rates of total nitrogen after stabilization were 65.00% and 58.02%, respectively, indicating that the removal effect of total nitrogen by the multi-spherical suspended biological carrier of the present invention is better than that of the traditional commercially available double-spherical biological carrier. In addition, the total nitrogen in the effluent of Example 4 and Example 5 tended to be stable after 45 days, and the average concentrations of total nitrogen after stabilization were 18.05 and 19.19 mg / L, respectively, reaching the Class B standard for water pollutant discharge from urban sewage treatment plants; and the average removal rates were higher than those of Comparative Example 1, at 75.24% and 73.68%, respectively, indicating that inoculating different functional strains in the multi-spherical suspended biological carrier of the present invention can significantly improve the removal effect of total nitrogen.

[0048] Example 9 Differences in extracellular polymer content in suspended biological carriers in various sewage treatment reactors After the reactor stopped running, the protein and polysaccharide contents in the samples were detected by BCA kit method and phenol-sulfuric acid method respectively. The specific steps are as follows: BCA kit method for protein content detection: Using bovine serum albumin (BSA) as the standard, the BCA protein concentration assay kit (Biosharp BL521A) was used to detect the protein content. Take 100 μL of the sample to be tested, add 2 mL of BCA working solution, mix well, and place at 37 °C for 30 min. Measure the absorbance at 562 nm. Use the PBS buffer treatment group as a blank control. Calculate the protein content based on the standard curve.

[0049] Phenol-sulfuric acid method to detect polysaccharide content: Take 1.0 mL of polysaccharide sample, then add 0.5 mL of 6% phenol, quickly add 2.5 mL of concentrated sulfuric acid, shake on a vortex, mix thoroughly, let stand for 30 min, and measure the absorbance at 490 nm. Use the distilled water treatment group as a blank control. Calculate the polysaccharide content based on the standard curve.

[0050] like Figure 8 As shown, the extracellular polymer contents of Example 4, Example 5, Comparative Example 1 and Comparative Example 2 are 175, 171, 130 and 95.2 mg / L, respectively. Among them, the extracellular polymer content of Comparative Example 1 is significantly higher than that of Comparative Example 2, indicating that the extracellular polymer content of the multi-spherical suspended biological carrier of the present invention is higher than that of the commercially available double-spherical suspended biological carrier. In addition, the extracellular polymer content of Examples 4 and 5 is significantly higher than that of Comparative Example 1, indicating that adding different functional strains to the multi-spherical suspended biological carrier of the present invention can increase the content of extracellular polymers, including proteins and polysaccharides. The significant increase in the content of extracellular polymers promotes the removal of pollutants such as COD, ammonia nitrogen and total nitrogen.

[0051] Example 10 Analysis of the diversity of microbial communities in biofilms of various sewage treatment reactors The biofilm genomic DNA in each sewage treatment reactor was extracted, the 16S sequence of the genomic DNA was amplified by PCR, and then sequenced and the bacterial community structure was analyzed.

[0052] Alpha diversity is an indicator of species richness, diversity and uniformity. The results are shown in Table 2. The number of OTUs (Operational Taxonomic Units, OTUs, OTUs is an indicator of alpha diversity, reflecting the richness of the microbial community structure) and the Shannon index (Shannon) in Comparative Example 1 are significantly higher than those in Comparative Example 2, while the number of OTUs and the Shannon index in Example 4 and Example 5 are significantly higher than those in Comparative Example 2. It shows that compared with the traditional commercially available double-sphere suspended biological carrier, the multi-sphere suspended biological carrier of the present invention has more microbial species and richer community composition. In addition, inoculating different functional strains in the multi-sphere suspended biological carrier of the present invention can improve its alpha diversity in the sewage treatment process, and can have more microbial species and richer community composition.

[0053] Table 2 Analysis of bacterial α diversity index in biofilms of various sewage treatment reactors Sample name Number of OTUs Shannon Index Example 4 2012±23a 6.35±0.12a Example 5 2015±27a 6.26±0.08a Comparative Example 1 1790±32b 5.91±0.07b Comparative Example 2 1656±22c 5.65±0.05c Note: Means (± error) in the same column with the same letter after them are not significantly different (p> 0.05).

[0054] The bacterial community structure in biofilms of different sewage treatment reactors Fig. 9 As shown, the Nitrospira in Comparative Example 1 ( Nitrospira )、Bacillus( Bacillus )、Xanthomonas aureus( Flavobacterium ) and Nitrosomonas ( Nitrosomonas ) were 5.53%, 1.12%, 0.91% and 0.82% respectively, which were higher than 4.93%, 0.08%, 0.64% and 0.35% in Comparative Example 2, indicating that the bio-carrier of the present invention can better promote the colonization of microorganisms with sewage treatment functions, thereby improving the treatment effect of sewage treatment reactors on pollutants such as ammonia nitrogen, total nitrogen and COD. On the other hand, the Bacillus and Acinetobacter ( Acinetobacter )、Pseudomonas( Pseudomonas ), yellow bacillus, from the Comonas Comamonas )、Acidovorax( Acidovorax) and Nitrosomonas were in the range of 4.12%-4.76%, 1.76%-2.27%, 5.55%-6.85%, 1.25%-1.66%, 2.07%-2.54% and 0.97%-1.25%, respectively, which were significantly higher than 1.12%, 0.02%, 0.08%, 0.91%, 0.05%, 0.23% and 0.82% of Comparative Example 1. This indicates that the sewage treatment functional bacteria (such as heterotrophic nitrifying bacteria, quorum sensing bacteria, heterotrophic denitrifying bacteria and chemoautotrophic bacteria) fixed inside the biological carrier of the present invention grow in situ, diffuse from the inside to the outside and increase the relative abundance in the biofilm, thereby enhancing the bacterial quorum sensing, biofilm adhesion ability and pollutant removal ability of the sewage treatment system, improving the microbial activity and diversity in the system, enhancing the shock load resistance of the sewage treatment system, and maintaining efficient and stable treated water.

[0055] Example 11 Sewage treatment effect in actual sewage treatment process like Fig.10 The present invention uses Panda-Box-500 bioreactor (the equipment adopts mud membrane symbiotic ammonia oxidation biological treatment technology, with a size of 1.2*0.6*1.2 m) to verify the actual application effect of the microbial carrier of the present invention, and the sewage treatment capacity is 0.5 m 3 / d. The control group and the experimental group were respectively added with a commercially available double-ball biological carrier and a bioreactor added with the microbial carrier of the present invention (the carrier contained the bacterial composition of Example 1, Example 2 and Example 3 in equal proportions). The present invention uses actual sewage as experimental water to explore the effects of different microbial carriers on the actual sewage treatment effect.

[0056] Actual sewage COD treatment effect Fig.11 As shown, the COD effluent of the control group and the experimental group tended to stabilize after 45 days and 30 days, respectively. After stabilization, the average COD concentrations of the control group and the experimental group were 33.66 and 24.33 mg / L, respectively, and the average removal rates were 81.37% and 86.53%, respectively, indicating that compared with commercially available biological carriers, the addition of the microbial carrier of the present invention can achieve COD effluent stabilization faster and improve the COD removal rate.

[0057] The actual sewage ammonia nitrogen treatment effect is as follows Fig.12 As shown, the ammonia nitrogen effluent of the control group and the experimental group tended to stabilize after 48 days and 42 days, respectively. The average ammonia nitrogen concentrations after stabilization were 6.69 and 4.50 mg / L, respectively, and the average removal rates were 86.00% and 90.59%, respectively, indicating that compared with commercially available microbial carriers, the addition of the microbial carrier of the present invention can achieve ammonia nitrogen effluent stabilization faster and improve the ammonia nitrogen removal rate.

[0058] Actual sewage total nitrogen treatment effect Fig.13 As shown, the total nitrogen effluent of the control group and the experimental group tended to stabilize after 45 days and 36 days, respectively. The average total nitrogen concentrations after stabilization were 17.67 and 14.92 mg / L, respectively, and the average removal rates were 75.86% and 79.63%, respectively, indicating that compared with commercially available microbial carriers, the addition of the microbial carrier of the present invention can achieve total nitrogen effluent stabilization faster and improve the total nitrogen removal rate.

[0059] Example 12 Biofilm formation effects of different microbial carriers in actual sewage treatment process Take out the multi-spherical suspended microbial carrier from the reactor, rinse the surface of the microbial carrier with deionized water to remove impurities on the surface. Place the microbial carrier in a forced air drying oven, dry it at 105 °C to constant weight, weigh it and record it as W1; then pour the biological filler into a beaker, add a NaOH solution with a concentration of 1 mol / L, and bathe it in a water bath for 40 min. Then put it in an ultrasonic cleaner for 50 min, then use deionized water to clean the biofilm that falls off the surface of the filler, place it in a 105 °C oven to dry it to constant weight, weigh it and record it as W2. The calculation method of the weight of the biofilm on the unit weight of the biological filler is: ; Fig.14 and Fig.15 The figures are respectively the biofilm effect diagrams of different microbial carriers and the biofilm amount per unit carrier. The color of the microbial carrier of the experimental group is light yellow, the internal polyurethane filler is brown, and the biofilm amount of the control group and the experimental group are 0.044 and 0.066 g / g, respectively. This shows that the microbial carrier of the present invention has more microbial growth and colonization, and the effect is better than the commercially available microbial carrier, and the growth and colonization of microorganisms further enhance the removal effect of pollutants such as COD, ammonia nitrogen and total nitrogen.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A functional microbial carrier for sewage treatment, characterized in that: It consists of three different spheres, large, medium and small, as well as polyurethane fillers and immobilized functional bacteria. The large sphere is the outermost layer, the medium sphere is located inside the large sphere and is fixed on the rotating axis of the large sphere, rotating 360° around the rotating axis; the large sphere is concentric with the medium sphere; the rotating axis of the large sphere is coaxial with the top hole of the medium sphere; the small sphere and polyurethane fillers are located inside the medium sphere.

2. According to the sewage treatment functional microbial carrier according to claim 1, the diameter of the large ball is 7-12 cm, the diameter of the medium ball is 4-8 cm, and the diameter of the small ball is 1-3 cm.

3. The sewage treatment functional microbial carrier according to claim 1, characterized in that: The polyurethane filler is close to a rectangular parallelepiped in shape, with a side length of 1-2 cm, a pore size of 4-6 ppi, and a density of 0.4-0.6 g / cm 3 .

4. The sewage treatment functional microbial carrier according to claim 1, characterized in that: The large ball is formed by aligning two completely mirror-symmetrical hemispheres with each other, rotating 90°, and pressing downward. A hollow rotating shaft is provided on the top of each hemisphere, and a fine rib that can be pressed open is provided at the bottom of the rotating shaft. The small balls and polyurethane fillers are installed through this hollow rotating shaft. When the pressure is released, the ribs rebound by themselves and reduce the gaps in the holes to prevent the small balls and polyurethane fillers from falling out. Each hemisphere is composed of criss-cross dividing strips, and meshes are formed between the dividing strips. A circle of reinforcement rings is set at the maximum diameter of each hemisphere, and a barb-type structure that interlocks two hemispheres is provided inside the reinforcement ring.

5. The sewage treatment functional microbial carrier according to claim 1, characterized in that: The middle ball is formed by aligning two completely mirror-symmetrical hemispheres, rotating 90°, and pressing them downward. A hole is provided on the top of each hemisphere to match the rotating shaft of the large ball. During assembly, the hole is sleeved on the rotating shaft of the large ball and rotates 360° around the rotating shaft. After the large ball and the middle ball are assembled, the small ball and the polyurethane filler are loaded into the middle ball through the hollow rotating shaft of the large ball. Each hemisphere is composed of criss-cross dividing strips, and meshes are formed between the dividing strips. A circle of reinforcement rings is provided at the maximum diameter of each hemisphere, and a barb-type structure that interlocks the two hemispheres is provided inside the reinforcement ring.

6. The sewage treatment functional microbial carrier according to claim 1, characterized in that: The small ball is formed by docking two completely mirror-symmetrical hollow hemispheres, each of which is provided with a hole at the top, and fine ribs that can be pressed open are provided around the hole, and the immobilized bacterial composition falls into the small ball through the gap formed by pressing the ribs open, and when the pressure is released, the ribs rebound and reduce the gap in the hole to prevent the immobilized bacterial composition from flowing out; each hemisphere is thinnest at the top and thickest at the maximum radius; each hemisphere, except the top, is provided with evenly arranged small holes to form a spherical mesh porous structure, and the pore size of the small holes is smaller than the immobilized bacterial composition, so that the immobilized bacterial composition is wrapped therein.

7. The sewage treatment functional microbial carrier according to claim 1, characterized in that: The immobilized functional bacteria are composed of one or more of Bacillus, Pseudomonas, Acinetobacter, Xanthomonas, Comamonas, Nitrosomonas, and Acidovorax.

8. The sewage treatment functional microbial carrier according to claim 6, characterized in that: The immobilized functional bacteria are immobilized by a polyvinyl alcohol-sodium alginate embedding method, and a single bacterial species is immobilized in the same microsphere, or a composite bacterial species is immobilized in the same microsphere to prepare an immobilized bacterial composition with different functions.

9. The sewage treatment functional microbial carrier according to claim 1, characterized in that: The immobilized bacteria composition is mixed in different proportions, and after the large ball and the medium ball are assembled, the small ball and the polyurethane filler are loaded into the inside of the medium ball through the hollow rotating shaft of the large ball to obtain a sewage treatment functional microbial carrier.

10. Use of the sewage treatment functional microbial carrier according to any one of claims 1 to 9 in the field of sewage treatment.

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