Microbial carrier and preparation method thereof

Abstract

The invention relates to the technical field of sewage treatment, and discloses a microbial carrier and a preparation method thereof. The microbial carrier is of a columnar three-layer structure and sequentially comprises a microbial core, a coating interlayer and an outer supporting layer from inside to outside, the microbial core is a cross-linked porous short fiber column, the coating interlayer is made of fine denier fibers, and the outer supporting layer is made of coarse denier fibers. The pores in the surface of the microbial core can load a large number of microorganisms, it is guaranteed that the microorganisms have high concentration, the middle coating interlayer can intercept organic matter, sufficient nutrients are provided for the microorganisms, meanwhile, the microorganisms are prevented from falling off, the outer supporting layer has a dispersion effect on water flow, the microorganisms are prevented from making direct contact with the water flow, and the water quality is improved. The stable survival of microorganisms is ensured. The microbial carrier disclosed by the invention can be mounted in a honeycomb type fixed bed bioreactor and is used for continuously and efficiently treating sewage and wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly relates to a microbial carrier and a preparation method thereof. Background Art

[0002] Generally, the treatment methods of sewage and wastewater include physical methods, chemical methods, and microbial methods. The physical method has a large treatment capacity, but has disadvantages such as many equipment, long process, and high cost. The chemical method has high treatment accuracy, but has the problem of introducing other substances. The microbial method can efficiently degrade pollutants such as organic matter, ammonia nitrogen, and total phosphorus in sewage, and convert them into simple inorganic substances. Compared with traditional sewage treatment methods, the microbial treatment technology does not require expensive equipment and complex operation processes, has a low maintenance cost, does not produce secondary pollution, and the treated water quality can meet the agricultural irrigation water standard, and can even be directly used for farmland irrigation, realizing the resource utilization of sewage.

[0003] The core technology of the microbial treatment method is how to ensure the long-term activity, reusability, and high efficiency of sewage and wastewater treatment of microorganisms. If microorganisms are directly placed into sewage and wastewater, it is very difficult to achieve the recovery and concentration of microorganisms, and it can only be used for single treatment, and the effect of continuous treatment cannot be achieved. Chinese Patent Application CN113666573A discloses a biofilm carrier, a biofilm, and a sewage treatment device for sewage treatment, which adopts an inner and outer two-layer fiber filter layer structure, and the outer fiber filter layer is set to extend in a spiral shape, increasing the surface area of the carrier structure, thereby increasing the microorganism inoculation amount of the carrier structure, and at the same time increasing the contact area between the carrier structure and the sewage during sewage treatment, improving the sewage treatment efficiency. When the sewage flushes the outer fiber filter layer, since the fiber wire bundle extends in a spiral shape and the two ends of the fiber wire bundle are fixed and immovable, the rest of the fiber wire bundle can vibrate under the flushing of the sewage. When the fiber wire bundle vibrates, it will generate a certain impact force on the outer surface of the inner fiber filter layer, forcing the microorganisms on the inner fiber filter layer to vibrate to a certain extent, increasing the contact area between the microorganisms on the inner fiber filter layer and the sewage. The above technical solution realizes the continuous treatment of sewage, but only uses spiral fibers to load microorganisms, and cannot increase the concentration of the loaded microorganisms. Moreover, the way that microorganisms increase the contact area with sewage by the vibration of the fiber wire bundle impacted by sewage will cause the microorganisms to fall off, further reducing the concentration of microorganisms, and the long-term treatment of sewage cannot be achieved. Summary of the Invention

[0004] Aiming at the problems of the existing microbial carriers for treating sewage and wastewater, such as less microbial adhesion amount, low adhesion concentration, and insufficient contact with sewage and wastewater, the present invention provides a microbial carrier and a preparation method thereof.

[0005] The microbial carrier of the present invention has a columnar three-layer structure, which consists of a microbial core, a coating interlayer and an outer support layer from the inside to the outside. Among them, the microbial core is a cross-linked porous short fiber column loaded with microorganisms, the coating interlayer is a fine denier fiber, and the outer support layer is a coarse denier fiber.

[0006] In the microbial carrier of the present invention, the function of the microbial core is to load microorganisms, and the cross-linked porous structure on the surface of the fiber column can provide a large number of attachment points for the stable growth of the microbial community; the function of the coating interlayer outside the microbial core is, firstly, to disperse the impact of water flow to prevent the microorganisms from falling off, and secondly, to intercept the organic matter particles in the sewage to enrich nutrients for the microorganisms; the outermost support layer plays a protective role of skeleton support to prevent the internal structure of the microbial carrier from being damaged during the processes of processing, transportation and installation. The total length of the microbial carrier of the present invention is 30-60 cm, and the ratio of the radius of the microbial core, the layer thickness of the coating interlayer and the layer thickness of the outer support layer is 10:(1-5):(1-5).

[0007] Furthermore, the diameter of the microbial core is 0.2-1 cm, the surface pores are 0.1-5 μm, the short fibers are selected from one or more of PET short fibers, nylon short fibers or aramid short fibers, and PLA, PEG or EVA is used as the cross-linking agent; the fine denier fiber used for the coating interlayer is PA66 fiber or PET fiber with a fineness of 0.3 D-2 D; the coarse denier fiber used for the outer support layer is PA66 fiber or PA6 fiber with a fineness of 5 D-50 D.

[0008] The preparation method of the microbial carrier of the present invention is as follows: I. Preparation of the microbial core Mix the short fibers and the powder of the cross-linking agent evenly, then heat to melt the cross-linking agent, stir evenly to disperse the short fibers evenly in the melt to obtain a mixed melt, inject the mixed melt into a circular mold, demold after natural cooling to obtain a short fiber column, blow the short fiber column with hot nitrogen under uniform rotation, observe the cross-linking agent on its surface to melt and then cool, clean it and then place it in the microbial slurry, soak for 1-5 months to obtain the microbial core; II. Preparation of the microbial carrier Coat the microbial core obtained in step I with fine denier fiber and coarse denier fiber respectively, cut it into the required length and then fix both ends to obtain it.

[0009] In the first step of the above method, the short fibers are made of PET, nylon or aramid, and the cross-linking agent is made of PLA, PEG or EVA. The melting point of the short fibers is much higher than that of the cross-linking agent, and the short fibers can stably exist in the melt of the cross-linking agent. After being prepared into a short fiber column, the cross-linking agent melts and flows out under the purging of hot nitrogen. After cooling, the cross-linking agent melt attached to the surface of the short fibers solidifies again to weld the short fibers, forming a structure with a large number of holes on the surface. According to the diameter of the microbial core and the pore diameter of the surface voids, the present invention controls the weight ratio of the short fibers to the cross-linking agent to be (3-7):1. For easy demolding, the material of the circular mold is selected from polytetrafluoroethylene, 304 stainless steel or 316 stainless steel.

[0010] The pores on the surface of the microbial core inside the microbial carrier of the present invention can load a large number of microorganisms, ensuring a high concentration of microorganisms during the continuous treatment of sewage and wastewater. The intermediate coating layer can intercept organic matter, provide sufficient nutrients for the microorganisms while preventing the microorganisms from falling off, and the outer support layer has a certain dispersing effect on the water flow, avoiding direct contact between the microorganisms and the water flow, and ensuring that the microorganisms can stably survive in the voids for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic longitudinal sectional view of the microbial carrier of the present invention.

[0012] Figure 2 It is a schematic cross-sectional view of the microbial carrier of the present invention.

[0013] Figure 3 It is a schematic view of the honeycomb fixed-bed bioreactor of the present invention.

[0014] Figure 4 It is a photograph of the microbial carrier before use in the honeycomb fixed-bed bioreactor of the present invention.

[0015] Figure 5 It is a photograph of the microbial carrier on the suspension beam after 1 year of use in the honeycomb fixed-bed bioreactor of the present invention.

[0016] Reference numerals: 1, microbial carrier; 11, microbial core; 12, coating layer; 13, outer support layer; 2, vertical frame; 3, fixing plate; 4, square frame; 5, suspension beam. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Embodiment 1

[0018] As Figure 1 and Figure 2As shown, a microbial carrier 1, with a length of 50 cm, is a columnar three-layer structure, which from the inside to the outside is successively a microbial core 11, a coating interlayer 12 and an outer support layer 13. The microbial core 11 is a cross-linked porous short fiber column loaded with microorganisms, the coating interlayer 12 is a fine denier fiber, and the outer support layer 13 is a coarse denier fiber. The ratio of the radius of the microbial core 11, the thickness of the coating interlayer 12 and the thickness of the outer support layer 13 is 10:5:3.

[0019] Specifically, the diameter of the microbial core 11 is 0.5 cm, the surface pores are 5 μm, the short fibers are PET short fibers, and the cross-linking agent is PLA; the fine denier fibers of the coating interlayer 12 are PA66 fibers with a fineness of 2 D; the coarse denier fibers of the outer support layer 13 are PA66 with a fineness of 50 D.

[0020] The preparation method of the microbial carrier 1 in this embodiment includes the following steps: 1) Mix PET short fibers and PLA powder evenly according to a weight ratio of 5:1, then heat to 210 °C to melt the PLA, stir evenly to disperse the PET short fibers evenly in the PLA melt to obtain a mixed melt. Inject the mixed melt into a polytetrafluoroethylene ring mold with an inner diameter of 0.5 cm, demold after natural cooling to obtain a short fiber column. Blow the short fiber column with hot nitrogen at 190 °C while rotating at a constant speed to melt the PLA on the surface. After cooling, observe whether the surface of the short fiber column has a porous structure. After confirmation, clean the excess PLA on the surface, place it in microbial slurry, and soak for 3 months to obtain the microbial core 11 loaded with microorganisms; 2) Wrap the microbial core 11 obtained in step 1) with fine denier fibers and coarse denier fibers respectively, cut it into the required length, and then fix both ends to obtain it. Example 2

[0021] As Figure 1 and Figure 2 shown, a microbial carrier 1, with a length of 60 cm, is a columnar three-layer structure, which from the inside to the outside is successively a microbial core 11, a coating interlayer 12 and an outer support layer 13. The microbial core 11 is a cross-linked porous short fiber column loaded with microorganisms, the coating interlayer 12 is a fine denier fiber, and the outer support layer 13 is a coarse denier fiber. The ratio of the radius of the microbial core 11, the thickness of the coating interlayer 12 and the thickness of the outer support layer 13 is 10:3:1.

[0022] Specifically, the diameter of the microbial core 11 is 1 cm, the surface pores are 3 μm, the short fibers are para-aramid short fibers, and the cross-linking agent is EVA; the fine denier fibers of the coating interlayer 12 are PET fibers with a fineness of 1 D; the coarse denier fibers of the outer support layer 13 are PA6 with a fineness of 30 D.

[0023] The preparation method of the microbial carrier 1 in this embodiment includes the following steps: 1) Mix para-aramid short fibers and EVA powder evenly at a weight ratio of 7:1, then heat to 110°C to melt the EVA. Stir evenly to disperse the para-aramid short fibers uniformly in the EVA melt, obtaining a mixed melt. Inject the mixed melt into a 304 stainless steel tube circular mold with an inner diameter of 1 cm. After natural cooling, demold to obtain a short fiber column. Blow the short fiber column with hot nitrogen at 120°C while rotating it at a constant speed to melt the EVA on the surface. After cooling, observe whether the surface of the short fiber column has a porous structure. After confirmation, clean the excess EVA on the surface and place it in microbial mud, soak for 1 month to obtain the microbial core 11 loaded with microorganisms; 2) Wrap the microbial core 11 obtained in step 1) with fine denier fibers and coarse denier fibers respectively, cut to the required length, and fix both ends to obtain it. Example 3

[0024] As Figure 1 and Figure 2 shown, a microbial carrier 1 has a length of 30 cm and is a columnar three-layer structure, which consists of a microbial core 11, a coating sandwich layer 12, and an outer support layer 13 from the inside to the outside. The microbial core 11 is a cross-linked porous short fiber column loaded with microorganisms, the coating sandwich layer 12 is fine denier fibers, and the outer support layer 13 is coarse denier fibers. The ratio of the radius of the microbial core 11, the thickness of the coating sandwich layer 12, and the thickness of the outer support layer 13 is 10:1:5.

[0025] Specifically, the diameter of the microbial core 11 is 0.2 cm, the surface pores are 0.1 μm, the short fibers are PA66 short fibers, and the cross-linking agent is PEG4000; the fine denier fibers of the coating sandwich layer 12 are PA66 fibers with a fineness of 0.3 D; the coarse denier fibers of the outer support layer 13 are PA66 with a fineness of 5 D.

[0026] The preparation method of the microbial carrier 1 in this example includes the following steps: 1) Mix PA66 short fibers and PEG4000 powder evenly at a weight ratio of 3:1, then heat to 70°C to melt the PEG4000. Stir evenly to disperse the PA66 short fibers uniformly in the PEG4000 melt, obtaining a mixed melt. Inject the mixed melt into a 316 stainless steel tube circular mold with an inner diameter of 0.2 cm. After natural cooling, demold to obtain a short fiber column. Blow the short fiber column with hot nitrogen at 80°C while rotating it at a constant speed to melt the PEG4000 on the surface. After cooling, observe whether the surface of the short fiber column has a porous structure. After confirmation, clean the excess PEG4000 on the surface and place it in microbial mud, soak for 5 months to obtain the microbial core 11 loaded with microorganisms; 2) Wrap the microbial core 11 obtained in step 1) with fine denier fibers and coarse denier fibers respectively, cut to the required length, and fix both ends to obtain it.

[0027] AsFigure 3 As shown, a honeycomb fixed-bed bioreactor for sewage treatment. The honeycomb fixed-bed bioreactor is a cuboid composed of four hollow vertical frames 2 and two upper and lower square frames 4. A number of fixed plates 3 are provided parallel to the long side of the square frame 4, and both ends of the fixed plate 3 are fixed on the vertical frame 2. A number of suspension beams 5 are provided parallel to the short side of the square frame 4, and both ends of each suspension beam 5 are fixed on the fixed plate 3. The distance between adjacent suspension beams 5 is 40 cm. Both ends of the microbial carrier 1 obtained in Example 1 are respectively fixed between two adjacent suspension beams 5. In the above honeycomb fixed-bed bioreactor, the microbial carrier 1 can swing freely, and there is no need to adjust the flow direction of the sewage, nor will there be a problem of uneven contact between the microorganisms and the sewage.

[0028] Figure 4 This is a photo of the microbial carrier in the honeycomb fixed-bed bioreactor of the present invention before use. It can be seen that the unused microbial carrier is in a fluffy state as a whole, and the microbial core is evenly wrapped without being exposed. Figure 5 This is a photo of the microbial carrier on the suspension beam after 1 year of use in the honeycomb fixed-bed bioreactor of the present invention. It can be seen that after 1 year of use, the microbial carrier as a whole maintains a complete structure, without falling off or agglomerating, and the organic matter in the sewage is evenly attached to the coating sandwich layer and the outer support layer.

[0029] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A microbial carrier, characterized in that, The microbial carrier (1) has a columnar three-layer structure, which consists of a microbial core (11), a coating interlayer (12), and an outer support layer (13) from the inside to the outside. The microbial core (11) is a cross-linked porous short fiber column loaded with microorganisms. The coating interlayer (12) is a fine denier fiber, and the outer support layer (13) is a coarse denier fiber.

2. The microbial carrier according to claim 1, wherein The ratio of the radius of the microbial core (11), the layer thickness of the coating interlayer (12), and the layer thickness of the outer support layer (13) is 10:(1~5):(1~5).

3. The microbial carrier according to claim 2, characterized in that, The diameter of the microbial core (11) is 0.2~1 cm, the surface pores are 0.1~5 μm, and the short fibers are selected from one or more of PET short fibers, nylon short fibers, or aramid short fibers. PLA, PEG, or EVA is used as the cross-linking agent.

4. The microbial carrier according to claim 2, characterized in that, The fine denier fiber is a PA66 fiber or a PET fiber with a fineness of 0.3D~2D.

5. The microbial carrier according to claim 2, wherein The coarse denier fiber is a PA66 fiber or a PA6 fiber with a fineness of 5D~50D.

6. The microbial carrier according to any one of claims 3 to 5, characterized in that, The length of the microbial carrier (1) is 30~60 cm.

7. A method for preparing the microbial carrier according to claim 6, characterized in that, It includes the following steps: I. Prepare the microbial core (11) Mix the short fibers and the powder of the cross-linking agent evenly, then heat to melt the cross-linking agent, stir evenly to disperse the short fibers uniformly in the melt, obtain a mixed melt, inject the mixed melt into a circular mold, demold after natural cooling, obtain a short fiber column, blow the short fiber column with hot nitrogen while rotating at a constant speed, observe the cross-linking agent on its surface to melt and then cool, clean it and then place it in the microbial slurry, soak for 1~5 months to obtain the microbial core (11); II. Prepare the microbial carrier (1) Coat the microbial core (11) obtained in step I with fine denier fiber and coarse denier fiber respectively, cut it into the required length, and then fix both ends to obtain it.

8. The preparation method of the microbial carrier according to claim 7, wherein, In step I, the weight ratio of the short fibers to the cross-linking agent is (3~7):

1.

9. The preparation method of the microbial carrier according to claim 7, characterized in that, In step I, the circular mold is a polytetrafluoroethylene tube, a 304 stainless steel tube, or a 316 stainless steel tube.

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