Device and method for reducing aerobic granular sludge MBR membrane pollution and energy consumption

Abstract

The invention relates to the technical field of sewage treatment, in particular to a device and method for reducing aerobic granular sludge MBR membrane pollution and energy consumption, the device comprises an anaerobic zone, an aerobic zone and an anoxic zone, the anaerobic zone and the anoxic zone are arranged side by side in parallel, and the anaerobic zone, the aerobic zone and the anoxic zone are sequentially connected according to the water flow direction; sludge in the anaerobic zone is in a satiation state, and the size of the anaerobic zone is respectively smaller than the size of the anoxic zone and the size of the aerobic zone; a plurality of aeration units for supplying oxygen to sludge and increasing hydraulic shear force are arranged in the aerobic zone; sludge at the tail end of the aerobic zone and in the anoxic zone is in a starvation state, a vibrating membrane assembly is arranged in the anoxic zone, and the vibrating membrane assembly generates low-amplitude vibration to enable membrane filaments and a water body to form relative movement. According to the invention, the vibration MBR bioreactor is utilized, high shear force caused by strong aeration can be avoided, and by combining satiation-hunger and sludge screening design, the formation of aerobic granular sludge can be promoted, the sludge can be intercepted by the membrane assembly, and a secondary sedimentation tank is saved.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a device and a method for reducing aerobic granular sludge MBR membrane pollution and energy consumption. Background Art

[0002] Wastewater treatment is a typical high-energy consumption industry and an important source of global carbon emissions. The water industry urgently needs to develop and apply pollution reduction and carbon reduction synergistic technologies to support the development of green and low-carbon wastewater treatment.

[0003] Aerobic granular sludge process is considered to be one of the most promising wastewater biological treatment technologies. It has a dense particle structure, good sedimentation performance, high biomass and activity. Aerobic granular sludge has an oxygen distribution gradient from the inside to the outside, forming an anaerobic, anoxic and aerobic coupling structure. Therefore, it has the function of simultaneously removing organic matter, nitrogen and phosphorus, and can significantly improve the degradation capacity of pollutants. In addition, aerobic granular sludge produces less sludge and settles faster than traditional activated sludge method, so it can significantly reduce the floor space and operating costs. At present, aerobic granular sludge is basically cultivated in sequencing batch reactors, which does not match the operation mode of existing continuous flow sewage treatment plants. Compared with sequencing batch aerobic granular sludge, continuous flow aerobic granular sludge technology has more research value and application potential, but its stability and start-up time are difficult to control and solve.

[0004] Membrane bioreactor (MBR) is a technology that combines biological treatment units with membrane separation units. This technology can maintain a high sludge concentration in the bioreactor, reduce floor space, improve effluent quality and reduce sludge production. It has been widely used in the water industry. However, MBR generally requires high aeration intensity to flush the membrane surface or use a high-pressure pump to provide a pressure difference to deal with membrane fouling, so there is a problem of high energy consumption. The characteristics of aerobic granular sludge can greatly reduce the fouling of membrane pores. Coupling aerobic granular sludge and membrane bioreactors provides the possibility of controlling membrane fouling.

[0005] MBR requires high aeration intensity to flush the membrane fibers to slow down pollution, but aerobic granular sludge is easy to disintegrate under high aeration intensity. Using different aeration intensities in the biochemical zone and membrane separation zone can slow down the disintegration of granular sludge, but providing high aeration intensity consumes a lot of energy. In addition, aerobic granular sludge processes usually adopt anaerobic-aerobic operation mode, so before the formation of mature granular sludge, the system may lack sufficient anoxic zone and have insufficient denitrification and denitrification capacity. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a device and method for reducing aerobic granular sludge MBR membrane pollution and energy consumption. The use of a vibrating MBR bioreactor can avoid high shear force caused by strong aeration. Combined with the satiation-starvation and sludge screening design, the formation of aerobic granular sludge can be promoted. The membrane module intercepts the sludge, saving the secondary sedimentation tank. The anoxic tank maintains a higher sludge concentration, eliminating the need for a return sludge setting from the bottom of the secondary sedimentation tank to the anoxic zone, and the structure is simpler.

[0007] The objective of the present invention is achieved through the following technical solutions: A device for reducing aerobic granular sludge MBR membrane pollution and energy consumption, comprising an anaerobic zone, an aerobic zone and an anoxic zone, wherein the anaerobic zone and the anoxic zone are arranged side by side in parallel, and the anaerobic zone, the aerobic zone and the anoxic zone are sequentially connected according to the direction of water flow; The sludge in the anaerobic zone is in a saturated state, and the size of the anaerobic zone is smaller than the size of the anoxic zone and the size of the aerobic zone respectively; The aerobic zone is provided with a plurality of aeration units for supplying oxygen to the sludge and increasing the hydraulic shear force; The sludge in the anoxic zone is in a starved state. A vibrating membrane assembly is provided in the anoxic zone. The vibrating membrane assembly generates low-amplitude vibrations to cause the membrane filaments to form relative motion with the water body.

[0008] Furthermore, the aeration unit includes an aeration plate disposed at the bottom of the aerobic zone and a blower connected to the aeration plate, and the blower is disposed outside the aerobic zone.

[0009] Furthermore, the vibration membrane assembly is driven by a motor.

[0010] Furthermore, the anaerobic zone is provided with a stirrer.

[0011] Furthermore, a sludge hopper is provided in the anoxic zone, and the sludge hopper is connected to the anaerobic zone through a sludge return pipe.

[0012] Furthermore, the anoxic zone is provided with a mud hopper mounting portion and a membrane assembly mounting portion, the surface of the mud hopper mounting portion is lower than the membrane assembly mounting portion, the sludge hopper is arranged in the mud hopper mounting portion, and the top surface of the sludge hopper is flush with the surface of the membrane assembly mounting portion; The vibrating membrane assembly is disposed at the membrane assembly mounting portion.

[0013] Furthermore, a plurality of the vibration membrane assemblies are provided, and the plurality of the vibration membrane assemblies are distributed in a rectangular array.

[0014] Furthermore, the hydraulic retention time of the anaerobic zone is 1 h-3 h, the hydraulic retention time of the aerobic zone is 4 h-6 h, and the hydraulic retention time of the anoxic zone is 4 h-6 h.

[0015] Furthermore, the volume of the anaerobic zone is less than 1 / 4 of the total volume of the anaerobic zone, the aerobic zone and the anoxic zone.

[0016] A sewage treatment method based on a device for reducing aerobic granular sludge MBR membrane pollution and energy consumption comprises the following steps: Step 1: Sewage continuously flows into the anaerobic zone and is fully mixed with sludge under the action of the agitator to form a mud-water mixture. The sludge fully utilizes the organic matter in the influent and converts part of the organic matter into an internal carbon source, while achieving anaerobic phosphorus release; Step 2: The mud-water mixture in step 1 enters the aerobic zone. Under aerobic conditions, the organic matter in the mud-water mixture is transformed and degraded, and part of the nitrogen and phosphorus are removed through microbial assimilation. At the same time, driven by the hydraulic shear force generated by the aeration unit and the alternating conditions of satiety and hunger, the microorganisms secrete extracellular polymers. Step 3: The sludge-water mixture in step 2 enters the anoxic zone, and the vibrating membrane assembly intercepts the sludge, so that the sludge concentration in the anoxic zone increases. At the same time, the vibrating membrane assembly generates low-amplitude vibration to make the membrane wire and the water body move relative to each other. The aerobic granular sludge with good settling performance first settles to the bottom of the anoxic zone under the action of the vibrating membrane assembly and gravity, thereby realizing sludge screening; Step 4: Return the aerobic granular sludge that first settles to the bottom of the anoxic zone in step 3 to the anaerobic zone.

[0017] The beneficial effects of the present invention are: 1) The present invention utilizes a vibrating MBR bioreactor to avoid high shear forces caused by strong aeration. Combining the satiation-starvation and sludge screening designs, the formation of aerobic granular sludge can be promoted. The membrane module intercepts sludge, saving the secondary sedimentation tank. The anoxic tank maintains a high sludge concentration, eliminating the need for a return sludge setting from the bottom of the secondary sedimentation tank to the anoxic zone, and the structure is simpler.

[0018] 2) At the same time, it ensures that during the startup phase (when particles are not formed), the system has sufficient anoxic environment for denitrification, which further improves the denitrification effect of the system and helps ensure that the effluent meets the standard stably; 3) Aerobic granular sludge operating in continuous flow has lower operating costs, is easier to operate, and has a larger sewage treatment capacity than sequencing batch aerobic granular sludge, so it has greater research value and application potential.

[0019] 4) The overall configuration is closer to a sewage treatment plant operating in AAO mode, and the engineering transformation is relatively simple.

[0020] 5) The sludge screening effect is increased, and the sludge with good settling performance is preferentially returned to obtain organic matter in the influent, which is beneficial to promote the formation of aerobic granular sludge. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The overall structure diagram of the device for reducing aerobic granular sludge MBR membrane pollution and energy consumption in the embodiment of the present invention; Figure 2 It is a cross-sectional view of the aerobic and anoxic zones; In the figure, 1, anaerobic zone; 2, aerobic zone; 3, anoxic zone; 4, aeration unit; 5, vibrating membrane assembly; 6, aeration plate; 7, blower; 8, agitator; 9, sludge hopper; 10, sludge return pipe. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1-Figure 2 , the present invention provides a technical solution: Embodiment 1: like Figure 1 and Figure 2 As shown, a device for reducing membrane pollution and energy consumption of aerobic granular sludge MBR comprises an anaerobic zone 1, an aerobic zone 2 and an anoxic zone 3, wherein the anaerobic zone 1 and the anoxic zone 3 are arranged side by side in parallel, and the anaerobic zone 1, the aerobic zone 2 and the anoxic zone 3 are sequentially connected according to the direction of water flow; The sludge in the anaerobic zone 1 is in a saturated state, and the size of the anaerobic zone 1 is smaller than the size of the anoxic zone 3 and the size of the aerobic zone 2; The aerobic zone 2 is provided with a plurality of aeration units 4 for supplying oxygen to the sludge and increasing the hydraulic shear force; The sludge at the end of the aerobic zone 2 and in the anoxic zone 3 is in a hungry state. A vibrating membrane assembly 5 is provided in the anoxic zone 3. The vibrating membrane assembly 5 generates low-amplitude vibrations to cause the membrane filaments to move relative to the water body (and thus flush the membrane filaments). The vibrating membrane assembly 5 intercepts the sludge, and under the combined effect of the force provided by its reciprocating motion and the vertical gravity, the aerobic granular sludge with better settling performance will preferentially settle to the bottom, so the membrane separation zone also has a screening effect on the intercepted sludge.

[0024] The aeration unit 4 includes an aeration plate 6 disposed at the bottom of the aerobic zone 2 and a blower 7 connected to the aeration plate 6 , and the blower 7 is disposed outside the aerobic zone 2 .

[0025] The vibration membrane assembly 5 is driven by a motor.

[0026] The anaerobic zone 1 is provided with a stirrer 8. Sewage continuously flows into the anaerobic zone 1 and is fully mixed with the sludge under the action of the stirrer 8. The sludge in the anaerobic zone 1 has sufficient available organic matter, and the sludge can fully utilize the organic matter in the influent and convert part of the organic matter into an internal carbon source, while achieving anaerobic phosphorus release.

[0027] The anoxic zone 3 is provided with a sludge hopper 9, which is connected to the anaerobic zone 1 through a sludge return pipe 10. The sludge hopper 9 cooperates with the sludge return pipe 10 and the air stripping device (the air stripping device is a prior art, and its working principle and specific structure are not described here) to realize the return of sludge to the anaerobic zone 1.

[0028] The anoxic zone 3 is provided with a mud hopper mounting portion and a membrane assembly mounting portion, the surface of the mud hopper mounting portion is lower than the membrane assembly mounting portion, the sludge hopper 9 is arranged in the mud hopper mounting portion, and the top surface of the sludge hopper 9 is flush with the surface of the membrane assembly mounting portion; The vibrating membrane assembly 5 is arranged at the membrane assembly installation portion, so that the sludge intercepted by the vibrating membrane assembly 5 can enter the sludge hopper 9 conveniently.

[0029] The vibrating membrane components 5 are provided in plurality, and the plurality of vibrating membrane components 5 are distributed in a rectangular array.

[0030] The hydraulic retention time of the anaerobic zone 1 is 1 h to 3 h, the hydraulic retention time of the aerobic zone 2 is 4 h to 6 h, and the hydraulic retention time of the anoxic zone 3 is 4 h to 6 h.

[0031] The volume of the anaerobic zone 1 is less than 1 / 4 of the total volume of the anaerobic zone 1 , the aerobic zone 2 and the anoxic zone 3 .

[0032] Working principle: (1) Sewage flows continuously into the anaerobic zone 1 and is fully mixed with the sludge by the agitator 8 to form a sludge-water mixture. The sludge in the anaerobic zone 1 has sufficient available organic matter (the sludge is in a saturated state). The sludge can fully utilize the organic matter in the influent and convert part of the organic matter into an internal carbon source, while achieving anaerobic phosphorus release.

[0033] (2) The sludge-water mixture enters the aerobic zone 2. Under aerobic conditions, aerobic microorganisms can further transform and degrade organic matter, and remove some nitrogen and phosphorus through microbial assimilation. The aeration unit 4 of the aerobic zone 2 can increase hydraulic shear force while providing oxygen to the sludge. The concentration of organic matter entering the aerobic zone 2 is low, and the sludge is mainly in a hungry state. Driven by hydraulic shear force and the alternating conditions of satiation and starvation, microorganisms can secrete more extracellular polymers, which is conducive to the formation and maintenance of aerobic granular sludge.

[0034] (3) The sludge-water mixture continues to enter the anoxic zone 3, and the effluent is separated by the membrane assembly and discharged into the subsequent treatment unit. Due to the interception effect of the vibrating membrane assembly 5, the anoxic zone 3 has a higher sludge concentration, and the sludge can make full use of the stored internal carbon source to achieve efficient denitrification and denitrification.

[0035] (4) The membrane assembly is driven by a motor to produce a slight horizontal reciprocating motion, causing the membrane filaments to move relative to the water body, thereby reducing membrane fouling. Compared with traditional aeration-type membrane fouling control technology, the vibration-type can achieve membrane fouling control while significantly reducing operating energy consumption.

[0036] Since aerobic granular sludge has a faster settling speed than flocculent sludge, under the combined effect of the force provided by the reciprocating motion of the vibrating membrane assembly 5 and the vertical gravity, aerobic granular sludge with better settling performance will first settle to the bottom, so the membrane separation zone also has a screening effect on the retained sludge.

[0037] The aerobic granular sludge that settles to the bottom first flows back to the front anaerobic zone 1 through the air stripping device, and is completely mixed with the influent water under the action of the agitator 8, so as to fully absorb and utilize the organic matter in the influent water.

[0038] Activated sludge goes through three stages: anaerobic-aerobic-anoxic. The anaerobic zone 1 is small, and there are more organic matter available to microorganisms, which is in a saturated environment. In the aerobic zone 2 and the anoxic zone 3, there are fewer organic matter available in the sewage, and the hydraulic time is longer, so the microorganisms are in a long-term starvation stage. In the alternating cycle, it will promote the microorganisms to convert more organic matter into internal carbon sources in the anaerobic zone 1. At the same time, the alternation of satiation and starvation promotes the microorganisms to secrete more extracellular polymers (EPS), which promotes the continuous aggregation of microorganisms. Under the combined action of appropriate hydraulic shear force and sludge screening, the agglomerated sludge has better sedimentation performance, will preferentially settle to the bottom, and be returned to the water inlet end, so that the cycle eventually forms dense granular sludge. In the traditional activated sludge-MBR bioreactor, due to the strong aeration flushing, the formed microbial aggregates are easily dispersed and disintegrated, and the formation of granular sludge is more difficult. The use of vibrating MBR bioreactors can avoid high shear forces caused by strong aeration, and combined with satiation-starvation and sludge screening designs, can promote the formation of aerobic granular sludge.

[0039] The present invention utilizes membrane components to intercept sludge, thus saving the secondary sedimentation tank. The anoxic tank maintains a relatively high sludge concentration, and eliminates the need for reflux sludge from the bottom of the secondary sedimentation tank to the anoxic zone 3, resulting in a simpler structure.

[0040] At the same time, it ensures that during the startup phase (when particles are not formed), the system has sufficient anoxic environment for denitrification and denitrification, which further improves the denitrification effect of the system and helps ensure that the effluent meets the standard stably. Aerobic granular sludge operating in continuous flow has lower operating costs, is easier to operate, and has a larger sewage treatment capacity than sequencing batch aerobic granular sludge, so it has greater research value and application potential.

[0041] The overall configuration is closer to a sewage treatment plant operating in AAO mode, and the engineering transformation is relatively simple.

[0042] The sludge screening effect is increased, and the sludge with good settling performance is preferentially returned to obtain organic matter in the influent, which is beneficial to promote the formation of aerobic granular sludge.

[0043] Embodiment 2: A sewage treatment method based on a device for reducing aerobic granular sludge MBR membrane pollution and energy consumption comprises the following steps: Step 1: Sewage continuously flows into the anaerobic zone 1, and is fully mixed with the sludge under the action of the agitator 8 to form a mud-water mixture. The sludge fully utilizes the organic matter in the influent and converts part of the organic matter into an internal carbon source, while achieving anaerobic phosphorus release; Step 2: The mud-water mixture in step 1 enters the aerobic zone 2, where the organic matter in the mud-water mixture is transformed and degraded under aerobic conditions, and part of the nitrogen and phosphorus are removed through microbial assimilation; at the same time, driven by the hydraulic shear force generated by the aeration unit 4 and the alternating conditions of satiety / hunger, the microorganisms secrete extracellular polymers; Step 3: The sludge-water mixture in step 2 enters the anoxic zone 3, and the vibrating membrane assembly 5 intercepts the sludge, so that the sludge concentration in the anoxic zone 3 increases. At the same time, the vibrating membrane assembly 5 generates low-amplitude vibration to make the membrane wire and the water body move relative to each other. The aerobic granular sludge with good settling performance first settles to the bottom of the anoxic zone 3 under the action of the vibrating membrane assembly 5 and gravity, thereby achieving sludge screening; Step 4: Return the aerobic granular sludge that first settles to the bottom of the anoxic zone 3 in step 3 to the anaerobic zone.

[0044] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A device for reducing aerobic granular sludge MBR membrane pollution and energy consumption, characterized by: It includes an anaerobic zone, an aerobic zone and an anoxic zone, wherein the anaerobic zone and the anoxic zone are arranged side by side in parallel, and the anaerobic zone, the aerobic zone and the anoxic zone are connected in sequence according to the direction of water flow; The sludge in the anaerobic zone is in a saturated state, and the size of the anaerobic zone is smaller than the size of the anoxic zone and the size of the aerobic zone respectively; The aerobic zone is provided with a plurality of aeration units for supplying oxygen to the sludge and increasing the hydraulic shear force; The sludge at the end of the aerobic zone and in the anoxic zone is in a starved state. A vibrating membrane assembly is provided in the anoxic zone. The vibrating membrane assembly generates low-amplitude vibrations to cause the membrane filaments to move relative to the water body.

2. The device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to claim 1, characterized in that: The aeration unit includes an aeration plate disposed at the bottom of the aerobic zone and a blower connected to the aeration plate, and the blower is disposed outside the aerobic zone.

3. The device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to claim 1, characterized in that: The vibrating membrane assembly is driven by a motor.

4. The device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to claim 1, characterized in that: The anaerobic zone is provided with a stirrer.

5. The device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to claim 1, characterized in that: A sludge hopper is provided in the anoxic zone, and the sludge hopper is connected to the anaerobic zone through a sludge return pipe.

6. The device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to claim 5, characterized in that: The anoxic zone is provided with a mud hopper mounting part and a membrane assembly mounting part, the surface of the mud hopper mounting part is lower than the membrane assembly mounting part, the sludge hopper is arranged in the mud hopper mounting part, and the top surface of the sludge hopper is flush with the surface of the membrane assembly mounting part; The vibrating membrane assembly is disposed at the membrane assembly mounting portion.

7. The device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to claim 6, characterized in that: The vibration membrane components are provided in plurality, and the plurality of vibration membrane components are distributed in a rectangular array.

8. The device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to claim 1, characterized in that: The hydraulic retention time of the anaerobic zone is 1 h to 3 h, the hydraulic retention time of the aerobic zone is 4 h to 6 h, and the hydraulic retention time of the anoxic zone is 4 h to 6 h.

9. The device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to claim 8, characterized in that: The volume of the anaerobic zone is less than 1 / 4 of the total volume of the anaerobic zone, the aerobic zone and the anoxic zone.

10. A method for treating sewage based on the device for reducing aerobic granular sludge MBR membrane pollution and energy consumption according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: Sewage continuously flows into the anaerobic zone and is fully mixed with sludge under the action of the agitator to form a mud-water mixture. The sludge fully utilizes the organic matter in the influent and converts part of the organic matter into an internal carbon source, while achieving anaerobic phosphorus release; Step 2: The mud-water mixture in step 1 enters the aerobic zone. Under aerobic conditions, the organic matter in the mud-water mixture is transformed and degraded, and part of the nitrogen and phosphorus are removed through microbial assimilation. At the same time, driven by the hydraulic shear force generated by the aeration unit and the alternating conditions of satiety / starvation, the microorganisms secrete extracellular polymers. Step 3: The sludge-water mixture in step 2 enters the anoxic zone, and the vibrating membrane assembly intercepts the sludge, so that the sludge concentration in the anoxic zone increases. At the same time, the vibrating membrane assembly generates low-amplitude vibration to make the membrane wire and the water body move relative to each other. The aerobic granular sludge with good settling performance first settles to the bottom of the anoxic zone under the action of the vibrating membrane assembly and gravity, thereby realizing sludge screening; Step 4: Return the aerobic granular sludge that first settles to the bottom of the anoxic zone in step 3 to the anaerobic zone.

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