AnDMBR dynamic membrane assembly for sludge anaerobic digestion

Abstract

The application discloses an AnDMBR dynamic membrane assembly for sludge anaerobic digestion, which comprises a membrane frame, a plurality of flat plate membranes, a detachable aeration pipe and a sludge feeding mechanism, the membrane frame is used for bearing various components of the AnDMBR dynamic membrane assembly; the plurality of flat plate membranes are arranged in parallel and equidistantly in the membrane frame; a membrane water outlet is arranged above the flat plate membranes; the detachable aeration pipe is arranged below the flat plate membranes, and the detachable aeration pipe utilizes circulating biogas to form a cross flow on the surface of the flat plate membranes; a plurality of air guide holes are arranged below the detachable aeration pipe; the sludge feeding mechanism is used for introducing low-concentration sludge between the flat plate membranes, and comprises a sludge feeding main pipe arranged above the plurality of flat plate membranes and a plurality of sludge feeding branch pipes communicated with the sludge feeding main pipe; the plurality of sludge feeding branch pipes and the plurality of flat plate membranes are alternately arranged in the membrane frame, and a plurality of flow guide holes are arranged on the sludge feeding branch pipes. The application can effectively control dynamic membrane pollution, reduce operation and management cost and realize long-term stable operation of the reactor.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sludge anaerobic digestion, and relates to an AnDMBR dynamic membrane assembly for sludge anaerobic digestion. BACKGROUND

[0002] The anaerobic dynamic membrane bioreactor (AnDMBR) is a water treatment technology combining membrane separation technology and activated sludge method. When applied to sludge anaerobic digestion, the AnDMBR can realize the increase of operating concentration by decoupling the hydraulic retention time (HRT) and the solid retention time (SRT). However, long-term high sludge concentration operation will inevitably make the dynamic membrane too thick, cause the formation of a linked sludge cake on the membrane surface, and thus result in excessively high membrane pressure or excessively low membrane flux, reducing the operation efficiency of the dynamic membrane, and even making the dynamic membrane unable to continue to be used. Therefore, the dynamic membrane assembly needs to be cleaned or replaced.

[0003] In a conventional AnDMBR process, the way of biogas circulation is generally adopted to form a membrane surface cross-flow rate to alleviate the sludge deposition on the membrane surface, so as to control the dynamic membrane pollution. However, the way of biogas circulation alone to control the membrane pollution has the following disadvantages: first, the sludge concentration in the AnDMBR system is high, the viscosity is large, and the sludge is a non-Newtonian fluid, so the membrane surface cross-flow rate formed by biogas circulation is limited; second, the biogas circulation amount depends on the sludge digestion effect. When the sludge digestion effect is poor and the biogas production is insufficient, the sludge cake on the membrane surface will rapidly deposit, so that the membrane assembly loses its efficiency.

[0004] In view of the above situation, in order to effectively control the dynamic membrane pollution and reduce the cleaning or replacement frequency of the membrane assembly, a new dynamic membrane assembly needs to be designed, which can effectively control the dynamic membrane pollution, reduce the operation and management cost, and realize the long-term stable operation of the reactor. SUMMARY

[0005] In view of the above defects in the prior art, the purpose of the present application is to provide an AnDMBR dynamic membrane assembly for sludge anaerobic digestion, which adopts a sludge inlet branch pipe to introduce low-concentration sludge to dilute the high-concentration sludge between the flat plate membranes, and uses a detachable gas pipe to accurately control the flushing of the flat plate membrane surface by the circulating biogas, so as to effectively control the dynamic membrane pollution, reduce the operation and management cost, and realize the long-term stable operation of the reactor.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] The present application provides an AnDMBR dynamic membrane assembly for sludge anaerobic digestion, comprising:

[0008] A membrane frame for carrying various components of the AnDMBR dynamic membrane assembly; the membrane frame is composed of a stainless steel grid;

[0009] A plurality of flat sheet membranes are arranged in parallel and equidistantly in the membrane frame; a membrane water outlet is arranged above the flat sheet membranes;

[0010] A detachable aeration pipe is arranged below the flat sheet membranes, which uses circulating biogas to form cross flow on the surface of the flat sheet membranes; a plurality of air guide holes are arranged below the detachable aeration pipe.

[0011] A sludge introduction mechanism is arranged to introduce low-concentration sludge between the flat sheet membranes; the sludge introduction mechanism comprises a sludge introduction main pipe arranged above the plurality of flat sheet membranes and a plurality of sludge introduction branch pipes connected to the sludge introduction main pipe; the plurality of sludge introduction branch pipes and the plurality of flat sheet membranes are arranged alternately in the membrane frame, and a plurality of flow guide holes are arranged on the sludge introduction branch pipes.

[0012] Preferably, the number of the detachable aeration pipes is consistent with the number of the flat sheet membranes.

[0013] Preferably, the angle between the air guide hole and the vertical direction on the detachable aeration pipe is 40-50°.

[0014] Preferably, the diameter of the air guide hole is 0.2-1.0 cm, and the distance between adjacent air guide holes is 2-8 cm.

[0015] Preferably, the number of the sludge introduction branch pipes is one more than the number of the flat sheet membranes.

[0016] Preferably, the diameter of the flow guide hole is 0.5-2.0 cm, and the distance between adjacent flow guide holes is 3-15 cm.

[0017] Advantages:

[0018] 1. The AnDMBR dynamic membrane assembly for sludge anaerobic digestion of the present application uses the sludge introduction branch pipe to introduce low-concentration sludge to dilute the high-concentration sludge between the flat sheet membranes, and uses the detachable aeration pipe to precisely control the circulating biogas to flush the surface of the flat sheet membranes, effectively controls the pollution of the dynamic membrane, reduces the operation and management cost, and realizes the long-term stable operation of the reactor.

[0019] 2. The AnDMBR dynamic membrane assembly for sludge anaerobic digestion of the present application uses the sludge introduction branch pipe to introduce low-concentration sludge to dilute the high-concentration sludge between the flat sheet membranes, and uses the circulating biogas to generate floating bubbles to form a certain cross flow rate on the surface of the dynamic membrane, generate membrane surface shear effect, effectively control membrane pollution, slow down the frequency of membrane assembly cleaning or replacement, and realize the long-term effective operation of the AnDMBR.

[0020] 3. The AnDMBR dynamic membrane assembly for sludge anaerobic digestion has low manufacturing cost and convenient maintenance and replacement, effectively controls dynamic membrane pollution by using sludge dilution and biogas circulation, reduces the frequency of membrane assembly cleaning or replacement, realizes long-term operation of the reactor, and can be popularized.

[0021] 4. The AnDMBR dynamic membrane assembly for sludge anaerobic digestion can realize rapid dilution of high-concentration sludge between flat membranes and accurately control the circulating biogas flushing area, relieve dynamic membrane pollution, and realize AnDMBR membrane pollution control.

[0022] 5. The AnDMBR dynamic membrane assembly for sludge anaerobic digestion effectively solves the problem of membrane surface mud cake deposition caused by the operation of AnDMBR under high-concentration sludge, prolongs the service life of the dynamic membrane, and helps the long-term stable operation of the AnDMBR reactor. BRIEF DESCRIPTION OF DRAWINGS

[0023] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the following drawings:

[0024] Figure 1 is a structural schematic view of the AnDMBR dynamic membrane assembly for sludge anaerobic digestion of the present application;

[0025] Figure 2 is a structural schematic view of the dynamic membrane assembly and the sludge inlet mechanism of the present application;

[0026] Figure 3 is a structural schematic view of the dynamic membrane assembly and the aeration pipe of the present application. DETAILED DESCRIPTION

[0027] In order to better understand the above technical solutions of the present application, the technical solutions of the present application will be further described below in combination with embodiments.

[0028] In combination with Figure 1 , Figure 2 , the present application provides an AnDMBR dynamic membrane assembly for sludge anaerobic digestion, which comprises a membrane frame 10, a plurality of parallel flat membranes 20 arranged in the membrane frame 10, a detachable aeration pipe 40 arranged below the flat membranes 20, and a sludge inlet mechanism for introducing low-concentration sludge between the flat membranes 20.

[0029] In combination with Figure 1 , the membrane frame 10 is used to carry various components of the AnDMBR dynamic membrane assembly; the membrane frame 10 is a cuboid composed of four stainless steel grids, which can fix the plurality of flat membranes 20 and the sludge inlet mechanism.

[0030] In combination withFigure 1 , Figure 2 As shown, multiple flat sheet membranes 20 are fixed in parallel and at equal intervals within the membrane frame 10; a membrane outlet 21 is provided above the flat sheet membrane 20; the substrate of the flat sheet membrane 20 is nylon, polyester and stainless steel wire mesh.

[0031] Combination Figure 1 , Figure 2 , Figure 3 As shown, the detachable aeration pipe 40 is parallel to the membrane surface of the flat sheet membrane 20 and is specifically installed below the flat sheet membrane 20. This detachable aeration pipe 40 utilizes the circulating biogas to create a cross-flow on the surface of the flat sheet membrane 20, which is used to precisely control the circulating biogas's scouring of the dynamic membrane layer formed on the surface of the flat sheet membrane 20 (see...). Figure 3 (As shown); the number of detachable aeration pipes 40 is the same as the number of flat sheet membranes 20, that is, when the number of flat sheet membranes 20 is n, the number of detachable aeration pipes 40 is also n, and the detachable aeration pipes 40 are arranged equidistantly and parallelly directly below the flat sheet membranes 20. Multiple air guide holes 41 are provided below each detachable aeration pipe 40. In a specific embodiment, the air guide holes 41 are located diagonally below the detachable aeration pipe 40, specifically, the angle between the air guide holes 41 and the vertical direction is 40-50°, to prevent sludge from depositing in the air guide holes 41 and causing blockage. Within a certain biogas circulation intensity range, such as 10-40m... 3 / (m 2 Under biogas circulation intensity of h), the airflow direction of the circulating biogas (see h) Figure 3 The direction shown in K is deviated from directly below by 40 to 50 degrees, which can form a crossflow velocity of 0.1 to 0.3 m / s on the surface of the dynamic membrane layer 22, generating a membrane shearing effect, thereby effectively controlling dynamic membrane fouling.

[0032] Combination Figure 2As shown, the sludge inlet mechanism is used to introduce low concentration sludge between the flat sheet membranes 20; the sludge inlet mechanism includes a sludge inlet main pipe 30 arranged above the plurality of flat sheet membranes 20 and a plurality of sludge inlet branch pipes 31 connected with the sludge inlet main pipe 30; the plurality of sludge inlet branch pipes 31 and the plurality of flat sheet membranes 20 are alternately arranged in the membrane frame 10, and the sludge inlet branch pipe 31 is arranged between the flat sheet membranes 20 from top to bottom at the side of the flat sheet membranes 20, the length of a single sludge inlet branch pipe 31 and the number of flow guide holes 32 are designed according to the height of the flat sheet membranes 20, in a specific embodiment, the number of sludge inlet branch pipes 31 is one more than the number of flat sheet membranes 20, for example, when the number of flat sheet membranes 20 is n, then the sludge inlet main pipe 30 in the main reaction zone is connected with n+1 sludge inlet branch pipes 31, the diameter of the gas guide pipe is 0.2-1.0 cm, and the distance between adjacent gas guide holes is 2-8 cm; in a specific embodiment, the diameter of the flow guide hole 32 is 0.5-2.0 cm, and the distance between adjacent flow guide holes 32 is 3-15 cm. The AnDMBR dynamic membrane assembly for sludge anaerobic digestion of the present application will be further described below with specific examples.

[0033] Example 1

[0034] In this embodiment, the AnDMBR dynamic membrane assembly for sludge anaerobic digestion described above is used for concentrating and separating the sludge after anaerobic digestion:

[0035] For the sludge anaerobic digestion AnDMBR system with a hydraulic retention time of 10 days, a solid retention time of 30 days, and a membrane zone sludge concentration of 32.4 g / L, taking one pair of symmetrical dynamic membrane assemblies as an example, the number of flat sheet membranes is 4, the distance between adjacent flat sheet membranes is 5 cm, the distance between the flat sheet membrane and the membrane frame is 3 cm, the height of the flat sheet membrane is 30 cm, the sludge inlet main pipe from the main reaction zone to the membrane zone is connected with 5 sludge inlet branch pipes, the sludge inlet branch pipes are inserted from top to bottom at the side of the flat sheet membranes, the distance between adjacent sludge inlet branch pipes is 5 cm, the vertical distance from the central axis of the sludge inlet branch pipe to the membrane surface of the flat sheet membrane is 2.5 cm, the inner diameter of the sludge inlet branch pipe is 1 cm, the length of a single sludge inlet branch pipe is 25 cm, 5 flow guide holes are symmetrically arranged on both sides of the sludge inlet branch pipe, the distance between adjacent flow guide holes is 5 cm, and the diameter of the flow guide hole is 0.5 cm; a detachable aeration pipe is arranged at the bottom of the membrane frame of the flat sheet membrane, the number of the detachable aeration pipe is 4, the detachable aeration pipe is arranged in parallel and equidistantly below the flat sheet membrane, when the biogas circulation intensity is 30 m 3 / (m 2 h), the outflow direction of the circulating biogas deviates 45° from the directly below, the diameter of the gas guide hole on the detachable aeration pipe is 0.5 cm, and the distance between adjacent gas guide holes is 5 cm. Under the conditions of a membrane flux of 5 LMH and a transmembrane pressure difference of less than 10 kPa, the AnDMBR system can be continuously and stably operated for more than 50 days without membrane cleaning.

[0036] Example 2

[0037] This example uses the above-mentioned AnDMBR dynamic membrane module for sludge anaerobic digestion to concentrate and separate sludge after anaerobic digestion:

[0038] This example is mostly the same as Example 1, the difference is that the hydraulic retention time is 10 days, the solid retention time is 40 days, the sludge concentration in the membrane zone is 51.2 g / L, the sludge anaerobic digestion AnDMBR system, the biogas circulation intensity is 35 m 3 / (m 2 h), under the conditions of membrane flux of 5 LMH and transmembrane pressure difference less than 10 kPa, the AnDMBR system can be continuously and stably operated for more than 50 days without membrane cleaning.

[0039] In summary, the present application introduces high-concentration sludge between the dilute sludge flat membranes by the sludge inlet branch pipe, and uses the circulating biogas to generate floating bubbles, to form a certain cross-flow rate on the surface of the dynamic membrane, to generate membrane surface shear effect, to effectively control membrane pollution, to slow down the frequency of membrane module cleaning or replacement, to realize long-term effective operation of AnDMBR; the AnDMBR dynamic membrane module for sludge anaerobic digestion of the present application has low manufacturing cost, convenient maintenance and replacement, effectively controls dynamic membrane pollution by using sludge dilution and biogas circulation, reduces the frequency of membrane module cleaning or replacement, realizes long-term operation of the reactor, and can be popularized.

[0040] Those skilled in the art in this technical field should realize that the above examples are only used to illustrate the present application, and are not used as a limitation on the present application, as long as the changes and modifications of the above-described examples are within the spirit and scope of the present application, they will fall within the scope of the claims of the present application.

Claims

1. An AnDMBR dynamic membrane assembly for anaerobic digestion of sludge, characterized in that, The application relates to a dynamic membrane bioreactor (DMBR) and a method for treating wastewater. The application comprises: a membrane frame for carrying various components of the DMBR dynamic membrane assembly; the membrane frame is composed of a stainless steel grid; a plurality of flat sheet membranes arranged in parallel and equidistantly in the membrane frame; the flat sheet membranes are provided with membrane water outlets above; a detachable aeration pipe arranged below the flat sheet membranes; the detachable aeration pipe utilizes circulating biogas to form a cross flow on the surface of the flat sheet membranes; a plurality of air guide holes are arranged below the detachable aeration pipe, Under the biogas circulation intensity of 10-40 m 3 / (m 2 h), the gas flow direction of the circulating biogas deviates 40-50° from the vertical direction, a cross flow rate of 0.1-0.3 m / s is formed on the surface of the dynamic membrane layer, a membrane surface shearing effect is generated, thereby effectively controlling the dynamic membrane pollution. the angle between the air guide holes and the vertical direction on the detachable aeration pipe is 40-50 DEG, which prevents sludge from depositing in the air guide holes and causing blockage, a sludge inlet mechanism for introducing low-concentration sludge between the flat sheet membranes; the sludge inlet mechanism comprises a sludge inlet main pipe arranged above the plurality of flat sheet membranes and a plurality of sludge inlet branch pipes connected with the sludge inlet main pipe; the plurality of sludge inlet branch pipes and the plurality of flat sheet membranes are alternately arranged in the membrane frame, and a plurality of flow guide holes are arranged on the sludge inlet branch pipes, 2. The AnDMBR dynamic membrane assembly for sludge anaerobic digestion according to claim 1, characterized in that, the number of the sludge inlet branch pipes is one more than that of the flat sheet membranes.

3. The An DMBR dynamic membrane assembly for sludge anaerobic digestion according to claim 1, characterized in that, The number of the detachable aeration pipes is consistent with that of the flat sheet membranes.

4. The An DMBR dynamic membrane assembly for sludge anaerobic digestion according to claim 1, characterized in that, The diameter of the air guide holes is 0.2-1.0 cm, and the distance between adjacent air guide holes is 2-8 cm. The diameter of the flow guide holes is 0.5-2.0 cm, and the distance between adjacent flow guide holes is 3-15 cm.

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