AnDMBR membrane zone integrated structure for sludge anaerobic digestion

Abstract

The application discloses an AnDMBR membrane area integrated structure 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 the dynamic membrane pollution, reduce the 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 membrane area integrated structure 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 running 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 it impossible 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 problem. However, the following disadvantages exist in the way of biogas circulation alone to control the membrane pollution: first, the sludge concentration in the AnDMBR system is high, and the viscosity is large, which is a non-Newtonian fluid. 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 digestion condition is poor and the biogas production is insufficient, the sludge cake on the membrane surface will be rapidly deposited, 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 membrane area integrated structure 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 circulating biogas to flush the flat plate membrane surface, 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 membrane area integrated structure for sludge anaerobic digestion, comprising:

[0008] A membrane frame for bearing 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 gas 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 angle between the gas guide hole and the vertical direction on the detachable aeration pipe is 40-50°.

[0013] Preferably, the diameter of the gas guide hole is 0.2-0.5 cm, and the distance between adjacent gas guide holes is 2-8 cm.

[0014] Preferably, the number of sludge introduction branch pipes is one more than the number of flat sheet membranes.

[0015] 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.

[0016] Preferably, the distance between adjacent flat sheet membranes is 3-8 cm, and the distance between the flat sheet membrane arranged close to the membrane frame and the membrane frame is > 2 cm.

[0017] Preferably, the circulating intensity of the circulating biogas of the detachable aeration pipe is 10-40 m 3 / (m 2 ·h), and the gas flow rate at the gas guide hole is 0.3-3 m / s.

[0018] Preferably, the sludge introduction branch pipe is arranged vertically to the sludge introduction main pipe.

[0019] Preferably, the sludge flow rate at the flow guide hole of the sludge introduction branch pipe is 0.05-0.30 m / s.

[0020] Preferably, the length of the sludge introduction branch pipe is less than the height of the flat sheet membrane.

[0021] The AnDMBR membrane zone integrated structure for sludge anaerobic digestion provided by the present application also has the following beneficial effects:

[0022] 1. The AnDMBR membrane area integrated structure for sludge anaerobic digestion of the present application adopts a sludge inlet branch pipe to dilute high-concentration sludge between flat membranes with low-concentration sludge, and utilizes a detachable air pipe to precisely control the flushing of the flat membrane surface by circulating biogas, effectively controls dynamic membrane pollution, reduces operation and management costs, and realizes long-term stable operation of the reactor

[0023] 2. The AnDMBR membrane area integrated structure for sludge anaerobic digestion of the present application introduces low-concentration sludge into high-concentration sludge between flat membranes through a sludge inlet branch pipe, optimizes the air guide hole diameter and spacing on the detachable aeration pipe, utilizes the circulating biogas to generate floating air bubbles, ensures that the cross flow formed by the biogas on the flat membrane surface has a suitable strength, forms a certain cross flow rate on the dynamic membrane surface, produces a membrane surface shearing effect, effectively controls membrane pollution, slows down the frequency of membrane module cleaning or replacement, and realizes long-term effective operation of the AnDMBR

[0024] 3. The AnDMBR membrane area integrated structure for sludge anaerobic digestion of the present application has low manufacturing cost and is convenient to repair and replace, utilizes sludge dilution and biogas circulation to effectively control dynamic membrane pollution, reduces the frequency of membrane module cleaning or replacement, realizes long-term operation of the reactor, and can be popularized

[0025] 4. The AnDMBR membrane area integrated structure for sludge anaerobic digestion of the present application can quickly dilute high-concentration sludge between flat membranes, precisely control the flushing area by circulating biogas, alleviate the pollution problem of the dynamic membrane, and effectively control AnDMBR membrane pollution

[0026] 5. The AnDMBR membrane area integrated structure for sludge anaerobic digestion of the present application effectively solves the problem of membrane surface mud cake deposition caused by the operation of AnDMBR with high-concentration sludge, prolongs the service life of the dynamic membrane through sludge dilution and biogas circulation mechanisms, and is helpful for the long-term stable operation of the AnDMBR reactor. BRIEF DESCRIPTION OF DRAWINGS

[0027] 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:

[0028] Figure 1 FIG. 1 is a structural schematic diagram of the AnDMBR membrane area integrated structure for sludge anaerobic digestion of the present application;

[0029] Figure 2 FIG. 2 is a structural schematic diagram of the dynamic membrane assembly and sludge inlet mechanism of the present application;

[0030] Figure 3 FIG. 3 is a structural schematic diagram of the dynamic membrane assembly and aeration pipe of the present application. DETAILED DESCRIPTION

[0031] In order to better understand the above technical solutions of the present application, the technical solutions of the present application are further described below in combination with examples.

[0032] As shown in Figure 1 , Figure 2 , the present application provides an AnDMBR membrane area integrated structure for sludge anaerobic digestion, which comprises a membrane frame 10, a plurality of parallelly arranged flat sheet membranes 20 arranged in the membrane frame 10, a detachable aeration pipe 40 arranged below the flat sheet membranes 20, and a sludge inlet mechanism for introducing low-concentration sludge between the flat sheet membranes 20.

[0033] As shown in Figure 1 , the membrane frame 10 is used for bearing various components of the AnDMBR dynamic membrane assembly; the membrane frame 10 is a cuboid shaped by four stainless steel grids, and can fix the plurality of flat sheet membranes 20 and the sludge inlet mechanism.

[0034] As shown in Figure 1 , Figure 2 , the plurality of flat sheet membranes 20 are fixed in the membrane frame 10 in parallel and equidistantly; a membrane water outlet 21 is arranged above the flat sheet membranes 20; and the base material of the flat sheet membranes 20 is nylon, polyester and stainless steel wire mesh. In a specific example, the spacing between adjacent flat sheet membranes is 3-8 cm, and the spacing between the flat sheet membrane arranged close to the membrane frame and the membrane frame is >2 cm; the present application equidistantly arranges the plurality of flat sheet membranes and controls the spacing between adjacent flat sheet membranes and the spacing between the flat sheet membrane on the outer side and the membrane frame, thereby ensuring the formation of the dynamic membrane layer on the surface of the flat sheet membrane.

[0035] As shown in Figure 1 , Figure 2 , Figure 3 , the detachable aeration pipe 40 is parallel to the membrane surface direction of the flat sheet membrane 20 and is specifically installed below the flat sheet membrane 20; the detachable aeration pipe 40 utilizes the circulating biogas to form a cross flow on the surface of the flat sheet membrane 20, and is used for precisely controlling the circulating biogas to flush the dynamic membrane layer formed on the surface of the flat sheet membrane 20 (see Figure 3 ); wherein the number of the detachable aeration pipe 40 is consistent with the number of the flat sheet membrane 20, that is, when the number of the flat sheet membrane 20 is n, the number of the detachable aeration pipe 40 is also n, and the detachable aeration pipe 40 is equidistantly and parallelly arranged directly below the flat sheet membrane 20. A plurality of air guide holes 41 are arranged below the detachable aeration pipe 40; in a specific example, the air guide holes 41 are arranged obliquely below the detachable aeration pipe 40, and specifically, the included angle between the air guide holes 41 and the vertical direction is 40-50°, so as to prevent the sludge from depositing in the air guide holes 41 and causing blockage. Within a certain range of biogas circulation intensity, such as 10-40 m 3 / (m2 h) the biogas circulation intensity, the gas flow direction of the circulating biogas (see the direction indicated by arrow K) deviates 40-50° from the direction directly below, and a cross-flow rate of 0.1-0.3 m / s can be formed on the surface of the dynamic membrane layer 22 to generate a membrane surface shearing effect, thereby effectively controlling the dynamic membrane pollution. Figure 3

[0036] In a specific embodiment, the diameter of the gas guide hole 41 on the detachable aeration pipe 40 is 0.2-0.5 cm, the distance between adjacent gas guide holes 41 is 2-8 cm, the circulation intensity of the circulating biogas of the detachable aeration pipe 40 is 10-40 m 3 / (m 2 ·h), and the gas flow rate at the gas guide hole 41 is 0.3-3 m / s. The present application optimizes the diameter and distance of the gas guide hole 41 on the detachable aeration pipe 40, and cooperates with the circulation intensity of the circulating biogas to ensure the gas flow rate at the gas guide hole 41, so that the cross-flow formed on the surface of the flat sheet membrane 20 has a suitable intensity, thereby effectively controlling the membrane pollution.

[0037] In combination with FIG. 1, the sludge feeding mechanism is used to introduce low-concentration sludge between the flat sheet membranes 20; the sludge feeding mechanism includes a sludge feeding main pipe 30 arranged above the plurality of flat sheet membranes 20 and a plurality of sludge feeding branch pipes 31 connected to the sludge feeding main pipe 30; the plurality of sludge feeding branch pipes 31 and the plurality of flat sheet membranes 20 are alternately arranged in the membrane frame 10, and the sludge feeding branch pipe 31 is provided with a plurality of flow guide holes 32. The sludge feeding branch pipe 31 is inserted between the flat sheet membranes 20 from top to bottom at the side of the flat sheet membranes 20, and the length of a single sludge feeding branch pipe 31 and the number of flow guide holes 32 are designed according to the height of the flat sheet membrane 20. In a specific embodiment, the number of sludge feeding 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, the sludge feeding main pipe 30 in the main reaction zone communicates with n+1 sludge feeding branch pipes 31. Figure 2 In a specific embodiment, the diameter of the flow guide hole 32 on the sludge feeding branch pipe 31 of the sludge feeding mechanism is 0.5-2.0 cm, and the distance between adjacent flow guide holes 32 is 3-15 cm. The sludge flow rate at the flow guide hole 32 of the sludge feeding branch pipe 31 is 0.05-0.30 m / s. The present application optimizes the diameter and distance of the flow guide hole 32 on the sludge feeding branch pipe 31 to ensure the flow rate of the low-concentration sludge to the flow guide hole, thereby effectively diluting the high-concentration sludge between the flat sheet membranes.

[0038] The AnDMBR membrane zone integrated structure for sludge anaerobic digestion of the present application is further described below in combination with a specific example.

[0039] Example 1

[0040]

[0041] ​​The AnDMBR membrane zone integrated structure for sludge anaerobic digestion is used for concentrating and separating sludge after anaerobic digestion.

[0042] For the sludge anaerobic digestion AnDMBR system with a hydraulic retention time of 10 days, a solid retention time of 30 days and a sludge concentration in the membrane zone of 32.4 g / L, one pair of symmetrical dynamic membrane assemblies is taken as an example, the number of flat plate membranes is 4, the distance between adjacent flat plate membranes is 5 cm, the distance between the flat plate membrane and the membrane frame is 3 cm, the height of the flat plate membrane is 30 cm, the main sludge inlet pipe of the main reaction zone is connected with 5 sludge inlet branch pipes, the sludge inlet branch pipes are inserted into the flat plate membrane from top to bottom at equal intervals on the side of the flat plate membrane, the distance between adjacent sludge inlet branch pipes is 5 cm, the vertical distance between the central axis of the sludge inlet branch pipe and the membrane surface of the flat plate 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, the hole diameter is 0.8 cm, the sludge injection flow rate is 1.5 m 3 / h, the sludge flow rate at the flow guide hole is 0.17 m / s; a detachable aeration pipe is arranged at the bottom of the membrane frame of the flat plate membrane, the number of the detachable aeration pipe is 4, the detachable aeration pipe is arranged below the flat plate membrane in parallel and at equal intervals with the direction of the flat plate membrane, when the biogas circulation intensity is 30 m 3 / (m 2 h), the outflow direction of the circulating biogas deviates from the directly below by 45°, the hole diameter of the gas guide hole on the detachable aeration pipe is 0.5 cm, the distance between adjacent gas guide holes is 4 cm, and the gas flow rate at the gas guide hole is 0.53 m / s. 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.

[0043] Example 2

[0044] The AnDMBR membrane zone integrated structure for sludge anaerobic digestion is used for concentrating and separating sludge after anaerobic digestion.

[0045] Most of the embodiment is the same as that of example 1, the difference is that the sludge anaerobic digestion AnDMBR system has a hydraulic retention time of 10 days, a solid retention time of 40 days and a sludge concentration in the membrane zone of 51.2 g / L, the hole diameter of the sludge inlet branch pipe flow guide hole is 1.0 cm, the sludge injection flow rate is 2.5 m 3 / h, the sludge flow rate at the flow guide hole is 0.18 m / s; when the biogas circulation intensity is 35 m 3 / (m 2 h), 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.

[0046] Example 3

[0047] This example uses the above-mentioned AnDMBR membrane zone integrated structure for sludge anaerobic digestion to concentrate and separate sludge after anaerobic digestion:

[0048] This example is mostly the same as Example 1, the difference being that the hydraulic retention time is 15 days, the solid retention time is 30 days, the membrane zone sludge concentration is 26.5 g / L of the sludge anaerobic digestion AnDMBR system, the aperture of the sludge inlet branch pipe guide hole is 0.5 cm, the sludge injection flow rate is 0.5 m 3 / h, the sludge flow rate at the guide hole is 0.14 m / s; when the biogas circulation intensity is 25 m 3 / (m 2 h), the gas flow rate at the gas guide hole is 0.45 m / s, 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 needing to clean the membrane.

[0049] In summary, the present application introduces high-concentration sludge between the dilute sludge inlet flat membranes by the sludge inlet branch pipe, and uses the circulating biogas to generate floating gas bubbles, to form a certain cross-flow rate on the dynamic membrane surface, to generate a membrane surface shear effect, to effectively control membrane pollution, to slow down the frequency of membrane module cleaning or replacement, to achieve long-term effective operation of the AnDMBR; the AnDMBR membrane zone integrated structure for sludge anaerobic digestion of the present application has low manufacturing cost and is convenient to repair and replace, effectively controls dynamic membrane pollution by using the dilution effect of the sludge inlet and the circulation effect of the biogas, reduces the frequency of membrane module cleaning or replacement, and achieves long-term operation of the reactor, and can be promoted.

[0050] Those skilled in the art of the present technology should recognize that the above examples are only used to illustrate the present application, and are not used as a limitation on the present application, and as long as the variations and modifications of the above-described examples are within the scope of the spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. An AnDMBR membrane zone integrated structure for sludge anaerobic digestion, characterized by, The application relates to a dynamic membrane bioreactor (DMBR) and a method for treating sewage. The application comprises: a membrane frame for bearing various components of the AnDMBR dynamic membrane assembly; the membrane frame is composed of a stainless steel grid; a plurality of flat plate membranes arranged in parallel and equidistantly in the membrane frame; the flat plate membranes are provided with membrane water outlets above; a detachable aeration pipe arranged below the flat plate membranes; 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 circulating strength of the circulating biogas of the detachable aeration pipe is 10-40 m 3 / (m 2 ·h), and the gas flow rate at the gas guide hole is 0.3-3 m / s; 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 pollution of the dynamic membrane. the angle between the air guide holes and the vertical direction on the detachable aeration pipe is 40-50 DEG, so as to prevent sludge from depositing in the air guide holes and causing blockage; a sludge feeding mechanism for introducing low-concentration sludge between the flat plate membranes; the sludge feeding mechanism comprises a sludge feeding main pipe arranged above the plurality of flat plate membranes and a plurality of sludge feeding branch pipes connected 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; 2. The AnDMBR membrane zone integrated configuration for sludge anaerobic digestion according to claim 1, wherein, the diameter of the flow guide holes is 0.5-2.0 cm, the distance between adjacent flow guide holes is 3-15 cm, and the sludge flow rate at the flow guide holes of the sludge feeding branch pipes is 0.05-0.30 m / s, so as to ensure the flow rate of the low-concentration sludge to the flow guide holes and effectively dilute the high-concentration sludge between the flat plate membranes.

3. The AnDMBR membrane zone integrated configuration for sludge anaerobic digestion according to claim 1, wherein, the diameter of the air guide holes is 0.2-0.5 cm, and the distance between adjacent air guide holes is 2-8 cm.

4. The AnDMBR membrane zone integrated configuration for sludge anaerobic digestion according to claim 1, wherein, The number of the sludge feeding branch pipes is one more than that of the flat plate membranes.

5. The AnDMBR membrane zone integrated configuration for sludge anaerobic digestion according to claim 1, wherein, The distance between adjacent flat plate membranes is 3-8 cm, and the distance between the flat plate membrane arranged close to the membrane frame and the membrane frame is greater than 2 cm.

6. The AnDMBR membrane zone integrated configuration for sludge anaerobic digestion according to claim 1, wherein, The sludge feeding branch pipes are arranged vertically with the sludge feeding main pipe. The length of the sludge feeding branch pipes is less than the height of the flat plate membranes.

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