Immersed membrane module device for MBR (Membrane Bioreactor) water treatment

Abstract

The invention relates to the technical field of MBR water treatment, in particular to an immersed membrane module device for MBR water treatment, which comprises an MBR membrane module device, the MBR membrane module device comprises a membrane assembly, the membrane assembly is a graphene ultrafiltration membrane assembly, the membrane assembly comprises a plurality of membrane filaments and a water production box, the upper end seal and the lower end of each membrane filament are inserted into a hole of the water production box for sealing and packaging, and the membrane filaments are arranged in the water production box. The MBR membrane module further comprises an aeration pipe I, an aeration pipe II, a water outlet, an aeration air inlet main opening, a water collecting pipe and a stainless steel frame; and the membrane module is mounted on the stainless steel frame. The flow rate of liquid on the surface of the membrane is changed in a mode of simultaneously aerating from the bottom and the side body of the membrane module, so that the adhesion of sludge flocs and pollutants on the surface of the membrane is reduced, the cleaning and replacing times in the use process of the membrane are reduced, and the operation and maintenance cost is reduced; the device has the advantages of compact structure, small occupied area, high membrane bundle strength, difficulty in scaling, good cleaning effect, less cleaning times compared with other products in the use process of the membrane component, convenience in installation and the like.

Description

Technical Field

[0001] The invention relates to the technical field of MBR water treatment, in particular to an immersed membrane module for MBR water treatment. Background Art

[0002] Membrane bioreactor is an advanced water treatment technology that integrates biological treatment technology and membrane separation technology. It uses microorganisms to degrade organic matter in sewage, and separates water and biological solids through the membrane separation process, so as to achieve the purpose of simultaneous biological reaction and solid-liquid separation. It has the advantages of excellent effluent quality, small footprint, low sludge production, and complete separation of hydraulic retention time and sludge retention time. According to the placement of the membrane assembly, the MBR process can be divided into external and submerged types. In the external MBR process, the bioreactor and the membrane assembly are set separately, and the mud and water are separated by a circulating pump. The submerged MBR means that the membrane assembly is directly placed in the bioreactor and the water is discharged by a pump. The operation of the external MBR is relatively independent and easy to control. The membrane assembly is placed outside the reactor, which is convenient for cleaning, replacement and membrane addition. Although the controllability of the submerged MBR is relatively poor and the membrane cleaning is relatively complicated, it greatly reduces the energy consumption and floor space of the treatment system. At present, submerged MBR is also widely used in actual engineering applications.

[0003] However, membrane pollution seriously limits the promotion and application of submerged MBR technology. Membrane pollution not only leads to frequent cleaning and replacement of membranes, increases the operation and maintenance costs of the system, but also affects the filtration and separation functions of the membrane, resulting in a decrease in the treatment effect of the system, and ultimately affects the effluent water quality. Therefore, it is of great significance to control and slow down membrane pollution. In the process of sewage treatment, the existing MBR will intercept impurities in sewage on the outside of the MBR. Although the existing aeration device and method can slow down the attachment of impurities in sewage to the membrane assembly to a certain extent, the impurities will eventually be gradually adsorbed on the outside of the MBR, which will affect the water filtration efficiency of the MBR. At present, when cleaning the impurities on the MBR by centrifugal mechanical means, the membrane bioreactor is disassembled, and then the disassembled MBR water treatment membrane is cleaned by a high-pressure water gun. Because the water flushing method will cause some positions to be unable to be flushed, workers are required to manually clean the positions that cannot be flushed. The above method takes a lot of time and the cleaning efficiency is extremely low. In order to address the shortcomings of the existing technology, the concentration, method and position of aeration on the module are changed to change the liquid flow rate on the membrane surface, thereby reducing the attachment of sludge flocs and pollutants on the membrane surface. An submerged membrane module for MBR water treatment is designed to reduce the number of cleaning and replacement times during the use of the membrane and reduce operation and maintenance costs. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned shortcomings in the prior art and to propose a submerged membrane module for MBR water treatment.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A submerged membrane module for MBR water treatment is designed, comprising an MBR membrane module, wherein the MBR membrane module comprises a membrane assembly, wherein the membrane assembly is a graphene ultrafiltration membrane assembly, wherein the membrane assembly comprises a plurality of membrane filaments and a water production box, wherein the upper end seal and the lower end of the membrane filament are both inserted into the hole of the water production box for sealing and packaging;

[0007] The MBR membrane module also comprises an aeration pipe 1, an aeration pipe 2, a water outlet, an aeration air inlet main port, a water collecting pipe, and a stainless steel frame, and the membrane assembly is installed on the stainless steel frame.

[0008] In detail, the aeration pipe 1 is installed at one side of the stainless steel frame, and the aeration pipe 2 is installed at the lower end of the stainless steel frame. The aeration pipe 1 and the aeration pipe 2 are connected to each other.

[0009] In detail, the water collecting pipe and the water outlet form a water collecting device, and the water collecting device is installed on a stainless steel frame.

[0010] In detail, an aeration main inlet is installed on one side of the stainless steel frame, and the aeration main inlet is fixedly connected to an aeration pipe.

[0011] In detail, the membrane fibers are hollow fiber structures and are made of PVDF material.

[0012] The design scheme proposed by the present invention has the following beneficial effects during application:

[0013] 1. By simultaneously aerating from the bottom and sides of the membrane module, the liquid flow rate on the membrane surface is changed, thereby reducing the attachment of sludge flocs and pollutants on the membrane surface, reducing the number of cleaning and replacement times during the use of the membrane, and reducing operation and maintenance costs.

[0014] 2. It has the advantages of compact structure, small footprint, high membrane bundle strength, not easy to scale, good cleaning effect, fewer cleaning times during the use of membrane components than other products, and easy installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the front view structure of a submerged membrane module for MBR water treatment according to the present invention;

[0016] Figure 2 A schematic diagram of a top view of a submerged membrane assembly for MBR water treatment according to the present invention;

[0017] Figure 3The figure is a schematic diagram of the side view structure of a submerged membrane assembly for MBR water treatment according to the present invention.

[0018] In the figure: 1. Aeration tube 1; 2. Aeration tube 2; 3. Membrane assembly; 4. Water outlet; 5. Aeration main air inlet; 6. Water collecting pipe; 7. Stainless steel frame. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] Reference Figure 1-3 , an immersed membrane module for MBR water treatment, including an MBR membrane module, the MBR membrane module includes a membrane assembly 3, the membrane assembly 3 is a graphene ultrafiltration membrane assembly, the membrane assembly 3 includes a plurality of membrane filaments and a water production box, the upper end of the membrane filament is sealed and the lower end is inserted into the hole of the water production box for sealing and packaging, and the upper and lower ends of the membrane filament are inserted into the water production box, and the generated clean water can be collected through the water production box and then output to the water outlet 4 through the water collection pipe 6, the upper and lower ends of the filament are sealed but not fixed, and under the natural flow of the water body or the airflow of the two aeration pipes, the unfixed membrane filaments can swing freely, which is conducive to removing the scale on the surface of the membrane filaments and enhancing the aeration cleaning effect;

[0021] The MBR membrane module also includes an aeration pipe 1, an aeration pipe 2, a water outlet 4, an aeration air inlet main port 5, a water collecting pipe 6, and a stainless steel frame 7, and the membrane assembly 3 is installed on the stainless steel frame 7.

[0022] It should be further explained that aeration pipe 1 is installed on one side of the stainless steel frame 7, and aeration pipe 2 is installed at the lower end of the stainless steel frame 7. Aeration pipe 1 and aeration pipe 2 are interconnected. When in use, the two aeration pipes located at the bottom and side are aerated at the same time, which can accelerate the biochemical reaction and reduce the adhesion of sludge on the membrane fibers to a certain extent.

[0023] It should be further explained that the water collecting pipe 6 and the water outlet 4 form a water collecting device, and the water collecting device is installed on the stainless steel frame 7 .

[0024] It should be further explained that an aeration main air inlet 5 is installed on one side of the stainless steel frame 7, and the aeration main air inlet 5 is fixedly connected to the aeration pipe 1.

[0025] It should be further explained that the membrane filaments are hollow fiber structures and are made of PVDF material.

[0026] Working method: During operation, due to the excellent filtering performance of the graphene ultrafiltration membrane and the simultaneous aeration of the aeration pipes located below and on the side during use, the membrane assembly described in the present disclosure can be cleaned in the following manner in actual operation and maintenance:

[0027] (1) Automatic backwash

[0028] Once every 12 hours (when the TMP device shows that the maximum transmembrane pressure difference is below 50kpa, the equipment is operating normally; when it shows greater than 50kpa, the equipment should be automatically backwashed with clean water).

[0029] (II) Online chemical cleaning

[0030] It is recommended to use sodium hypochlorite (NaClO) once a month. The dosage is 2.0L / m2 per time, plus the pipe volume. The concentration of the agent should be 1‰-3‰. When cleaning online, stop water production; stop aeration; start the backwash pump, and inject all the cleaning liquid into the membrane for 30min-40min; soak for 20min-30min; discharge the waste cleaning liquid. The waste cleaning liquid is discharged into the waste liquid storage tank or sewage pretreatment tank. Cleaning agent: sodium hypochlorite (NaClO) solution; agent preparation concentration: 500ppm; total amount of injected liquid: 2-4L / m2 membrane area.

[0031] Cleaning steps:

[0032] 1. Before online cleaning, first stop the suction pump to stop filtering, and close the valve on the suction water pipe; empty the membrane pool to a certain liquid level; stop aeration.

[0033] 2. Open the liquid injection tube and inject the liquid; add the liquid three times, one-third of the amount each time. Adding method: add the liquid for 5 minutes for the first time, and let it stand for 5 minutes; then add the liquid for the second time, add the liquid for 5 minutes, and let it stand for 3 minutes; then add the liquid for the third time, add the liquid for 5 minutes; after all the liquid is added, let it stand for 60-90 minutes. If the water temperature is low, consider heating the cleaning solution appropriately to increase the temperature, which can improve the cleaning effect (the recommended cleaning temperature is 20-35℃).

[0034] 3. After completing the above operations, open the suction tube, start the suction pump, and run it at half-flux for 30 minutes before starting normal operation again.

[0035] (III) Immersion cleaning (offline cleaning)

[0036] It is recommended to use once a year. The off-line cleaning agent should be sodium hypochlorite plus sodium hydroxide (NaCIO+NaOH) with a weight ratio of 1:1 and citric acid, and the concentration of the agent should be 3‰-5‰. The waste cleaning liquid is treated with activated carbon or sodium bisulfite and then returned to the

[0037] Pretreatment device. Immersion cleaning is performed when recovery cleaning cannot restore the pressure difference between membranes, or when sludge is attached between membranes due to a machine failure (sludge accumulation). The entire membrane assembly is soaked in liquid for a long time to remove membrane fouling and restore the pressure difference between membranes to the initial value. Compared with recovery cleaning, immersion cleaning has a better cleaning effect. Please perform immersion cleaning in the following order:

[0038] 1. Liquid concentration and soaking time

[0039] NaClO (effective chlorine concentration 3000mg / L): 6h-24h; acid (1-2% oxalic acid or citric acid, 0.1-0.5N sulfuric acid or hydrochloric acid): 2-4h.

[0040] 2. When cleaning the membrane components

[0041] ① Wash the membrane components before soaking;

[0042] ② Wash the membrane components again after soaking;

[0043] ③ In case of membrane separation tank separation type MBR system, the membrane components can be left unchanged, and only the sludge in the membrane separation tank can be replaced with liquid medicine and then soaked.

[0044] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A submerged membrane module for MBR water treatment, comprising an MBR membrane module, characterized in that: The MBR membrane module comprises a membrane assembly (3), the membrane assembly (3) is a graphene ultrafiltration membrane assembly, and the membrane assembly (3) comprises a plurality of membrane filaments and a water production box, the upper end seal and the lower end of the membrane filament are both inserted into the hole of the water production box for sealing and packaging; The MBR membrane module also comprises an aeration pipe 1 (1), an aeration pipe 2 (2), a water outlet (4), an aeration air inlet main port (5), a water collecting pipe (6), and a stainless steel frame (7), and the membrane assembly (3) is installed on the stainless steel frame (7).

2. The submerged membrane module for MBR water treatment according to claim 1, characterized in that: The aeration pipe 1 (1) is installed at one side of the stainless steel frame (7), and the aeration pipe 2 (2) is installed at the lower end of the stainless steel frame (7). The aeration pipe 1 (1) and the aeration pipe 2 (2) are connected to each other.

3. The submerged membrane module for MBR water treatment according to claim 1, characterized in that: The water collecting pipe (6) and the water outlet (4) form a water collecting device, and the water collecting device is installed on a stainless steel frame (7).

4. The submerged membrane module for MBR water treatment according to claim 1, characterized in that: An aeration air inlet main port (5) is installed on one side of the stainless steel frame (7), and the aeration air inlet main port (5) is fixedly connected to the aeration pipe 1 (1).

5. The submerged membrane module for MBR water treatment according to claim 1, characterized in that: The membrane fibers are hollow fiber structures and are made of PVDF material.

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