Membrane bioreactor system and sludge activation reduction method

Abstract

The invention provides a membrane bioreactor system and a sludge activation reduction method, and belongs to the technical field of sewage treatment, an MBR unit is communicated with a sludge property improvement unit through a feed inlet and a reflux inlet, the ratio of activated sludge MLVSS / MLSS at the reflux inlet is increased, activated sludge particles are reduced, the specific surface area is increased, and the activity is enhanced; concentration and inorganic matter enrichment of residual sludge at a sludge discharge port are realized, and the moisture content of the residual sludge is reduced after the residual sludge is treated by an original system. The sludge property improvement unit is provided with an intelligent control module, the sludge discharge amount is determined through inlet and outlet water quality, sludge concentration and the like, and operation parameters are regulated and controlled in real time according to the sludge discharge amount and the sludge concentration. The ratio of MLVSS / MLSS of the MBR unit is increased at the reflux inlet of the system, so that the system can operate at low sludge concentration, the aeration efficiency of the system is improved, the membrane pollution rate is reduced, sludge concentration and inorganic matter enrichment are realized at the sludge outlet, the factory water content of residual sludge or the dosage of a sludge dewatering agent can be reduced, and the investment cost and the operation cost are reduced.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a membrane bioreactor system and a method for sludge activation and reduction. Background Technology

[0002] Membrane bioreactor (MBR) technology, a wastewater treatment process combining ultrafiltration / microfiltration membrane separation with activated sludge, has developed rapidly due to its advantages such as good effluent quality, small footprint, and low sludge production. Currently, MBR projects with a capacity of over 10,000 tons account for more than 10% of the total wastewater treatment capacity. However, due to the high-precision membrane retention and long sludge age characteristics of the MBR process, the sludge contains high levels of impurities such as sand, slag, and microplastics, resulting in a low MLVSS / MLSS ratio in the activated sludge, typically only 0.4-0.5. To ensure wastewater treatment efficiency, wastewater treatment plants need to maintain a high sludge concentration, leading to low oxygen transfer efficiency, rapid membrane fouling, and long sludge age making dewatering difficult. This also results in high direct operating costs for electrochemical sludge treatment at wastewater treatment plants. Summary of the Invention

[0003] The purpose of this invention is to provide a membrane bioreactor system and a sludge activation and reduction method to solve at least one of the technical problems existing in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a membrane bioreactor system, comprising:

[0006] The membrane bioreactor unit and the sludge property improvement unit are connected by pipelines; wherein, the membrane bioreactor unit includes an anaerobic tank, a pre-anoxic tank, an aerobic tank, a post-anoxic tank and a membrane tank arranged in sequence.

[0007] Agitators are installed in the anaerobic tank, the pre-anoxic tank, and the post-anoxic tank; an aerator is installed in the aerobic tank; and a membrane module is installed in the membrane tank.

[0008] The sludge property improvement unit is equipped with a feed inlet, a return outlet, and a sludge discharge outlet. The sludge property improvement unit is connected to the membrane tank through the feed inlet and the return outlet. The feed inlet of the feed pump is located in the return channel of the membrane tank, the return outlet is located in the water distribution channel of the membrane tank, and the sludge discharge outlet is located at the front end of the excess sludge discharge pump.

[0009] The sludge property improvement unit is equipped with an intelligent control module, which adjusts the operating parameters of the sludge property improvement unit in real time according to the concentration effect of the sludge property improvement unit; a pressure gauge and a flow meter are installed at the feed inlet, and an online sludge concentration meter and a flow meter are installed at the discharge outlet.

[0010] As a further limitation of the first aspect of the present invention, the membrane tank is aerated by a blower to control membrane fouling, and the air-to-water ratio of the membrane tank is 6-10.

[0011] As a further limitation of the first aspect of the present invention, the return flow from the end of the pre-anoxic tank to the front of the anaerobic tank is a return flow ratio R1; the return flow from the end of the aerobic tank to the front of the pre-anoxic tank is a return flow ratio R2; when the membrane tank is aerated by a blower, the return flow from the end of the membrane tank to the front of the aerobic tank is a return flow ratio R3.

[0012] As a further limitation of the first aspect of the present invention, the membrane tank is controlled by a vibrating motor to control membrane fouling; the membrane module is reciprocated horizontally by a vibrating motor with a vibration frequency of 0.5-1Hz and an amplitude of 5-10cm.

[0013] As a further definition of the first aspect of the present invention, the recirculation from the end of the pre-anoxic tank to the front of the anaerobic tank is a recirculation ratio R1; the recirculation from the end of the aerobic tank to the front of the pre-anoxic tank is a recirculation ratio R2; when membrane fouling is controlled by a vibrating motor, the recirculation from the end of the membrane tank to the front of the pre-anoxic tank is a recirculation ratio R3.

[0014] As a further limitation of the first aspect of the present invention, an online sludge concentration meter and a water quality monitoring instrument are installed in the membrane tank to monitor the sludge concentration and the effluent water quality, and in combination with the influent water quality, thereby determining a suitable range of sludge concentration for the MBR unit.

[0015] Secondly, the present invention provides a method for sludge activation and reduction using the membrane bioreactor system described above, comprising: wastewater to be treated, after pretreatment, enters an anaerobic tank and mixes with sludge, remaining under anaerobic stirring conditions; the sludge mixture from the anaerobic tank is pushed into a pre-anoxic tank, remaining under stirring conditions; the sludge mixture from the pre-anoxic tank is pushed into an aerobic tank, remaining under aeration conditions; the sludge mixture from the aerobic tank is pushed into a post-anoxic tank, remaining under stirring conditions; the sludge mixture from the post-anoxic tank is pushed into a membrane tank, remaining there, where the membrane tank separates sludge and water by pumping permeate; the sludge mixture from the membrane tank is pumped into a sludge property improvement unit through an inlet located in the membrane tank return channel, the sludge from the return channel returns to the membrane tank distribution channel, and the remaining sludge is discharged from the sludge discharge outlet, the daily sludge discharge volume being determined by calculation based on the influent and effluent water quality and the membrane tank sludge concentration; the remaining sludge is discharged through the sludge discharge outlet of the sludge property improvement unit, based on the MLSS at the sludge discharge outlet. 排 and its relationship with MBR membrane pool MLSS 膜 Adjust the feed flow rate and sludge discharge flow rate according to the concentration ratio (i.e., the concentration factor). The sludge discharge flow rate should be 5%-15% of the feed flow rate of this unit to ensure MLSS at the sludge discharge port. 排The concentration ratio is between 1.4 and 4 times, while controlling the inlet pressure within a safe and economical range; based on the MLSS at the discharge port... 排 Calculate and control the operating time of the sludge property improvement unit by measuring EAS and sludge discharge flow rate.

[0016] As a further limitation of the second aspect of the present invention, the reflux ratio R1 is 100%-200%, the reflux ratio R2 is 200%-600%, the reflux ratio R3 is 400%-500% when the membrane tank is controlled by a blower aeration, and the reflux ratio R3 is 200%-300% when the membrane tank is controlled by a vibrating motor.

[0017] As a further limitation of the second aspect of the present invention, the formula for calculating the daily sludge discharge volume is as follows:

[0018]

[0019] Where TSS represents the total sludge volume; Q 设 Indicates the design influent flow rate; HRT 膜 HRT 后 HRT 好 HRT 前 HRT 厌 These represent the design hydraulic retention times (MLSS) for the membrane tank, post-anoxic tank, aerobic tank, pre-anoxic tank, and anaerobic tank, respectively. 膜 R1 represents the sludge concentration in the membrane tank; R3, R2, and R1 represent the membrane tank return ratio, aerobic tank return ratio, and pre-anoxic tank return ratio, respectively.

[0020]

[0021] EAS represents the amount of excess sludge; TN 进 TN 出 These represent the total nitrogen monitoring values ​​for influent and product water, respectively. These represent the ammonia nitrogen monitoring values ​​for influent and product water, respectively; TN 设 This indicates the set value for total nitrogen in the produced water; This indicates the set value for ammonia nitrogen in the produced water.

[0022] As a further limitation of the second aspect of the present invention, according to the MLSS of the sludge discharge port... 排 Calculate and control the operating time of the sludge property improvement unit based on EAS and sludge discharge flow rate:

[0023]

[0024] Where T represents the operating time of the sludge property improvement unit; MLSS 排 Indicates the sludge concentration at the sludge discharge outlet; Q 排 This indicates the flow rate at the sludge discharge outlet.

[0025] The beneficial effects of this invention are as follows: The MLVSS / MLSS ratio of the membrane bioreactor system can be increased by 10%-20%, enabling the system to operate under low MLSS conditions. This further increases oxygen mass transfer efficiency, reduces aeration in the aerobic tank, and mitigates membrane fouling. It replaces the original MBR membrane tank sludge discharge method, allowing excess sludge to be discharged via a sludge property improvement unit. MLSS concentration can be achieved by 1.4-4 times while enriching inorganic matter. New water plants do not need to design sludge thickeners, and existing water plants can surpass their existing sludge thickeners, reducing investment and operating costs. Inorganic matter enrichment improves sludge dewatering performance, further reducing the moisture content of excess sludge at the effluent or the dosage of sludge dewatering agents. It achieves enhanced sludge activity, reduced aeration, mitigated membrane fouling, reduced moisture content of excess sludge, and reduced dewatering agents, resulting in a reduction of electrochemical sludge costs by more than 10% compared to the original system.

[0026] The advantages of additional aspects of the invention will be set forth more clearly in the following description or will be learned by practice of the invention. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a functional principle block diagram of the improved membrane bioreactor system described in an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the MLVSS / MLSS separation effect according to an embodiment of the present invention.

[0030] Figure 3 This is a schematic diagram illustrating the sludge concentration effect at the sludge discharge port according to an embodiment of the present invention.

[0031] The system includes: 1. Pretreatment unit; 2. Anaerobic tank; 3. Agitator; 4. Pre-anoxic tank; 5. Aerobic tank; 6. Aerator; 7. Post-anoxic tank; 8. Aeration blower; 9. Membrane tank; 10. Membrane module; 11. Vibrating motor; 12. Feed pump; 13. Sludge property improvement unit; R1. Return from pre-anoxic tank to anaerobic tank; R2. Return from aerobic tank to pre-anoxic tank; R3. Return from membrane tank to pre-anoxic tank or aerobic tank. Detailed Implementation

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0033] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as here.

[0035] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or groups thereof.

[0036] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0037] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In the description of this specification, the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this technology and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this technology.

[0039] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of these terms in this art according to the specific circumstances.

[0040] To facilitate understanding of the present invention, the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. However, the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0041] Those skilled in the art should understand that the accompanying drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily essential for implementing the present invention.

[0042] like Figure 1As shown in this embodiment, a membrane bioreactor system is first provided. This system includes an MBR unit and a sludge property improvement unit connected by pipelines. Wastewater enters the MBR unit after passing through a pretreatment unit 1. The MBR unit comprises an anaerobic tank 2, a pre-anoxic tank 4, an aerobic tank 5, a post-anoxic tank 7, and a membrane tank 9 arranged sequentially. Agitators 3 are installed in the anaerobic tank 2, the pre-anoxic tank 4, and the post-anoxic tank 7 of the MBR unit, an aerator 6 is installed in the aerobic tank 5, and a membrane module 10 is placed in the membrane tank 9. The membrane tank 9 in the MBR unit can be aerated using a blower 8 or controlled for membrane fouling using a vibrating motor 11. When aeration is used with a blower, the air-to-water ratio in the membrane tank is 6-10. When a vibrating motor is used, the membrane module 10 achieves horizontal reciprocating motion via the vibrating motor 11, with a vibration frequency of 0.5-1Hz and an amplitude of 5-10cm. In the MBR system, reflux 1 is as follows: reflux from the end of the pre-anoxic tank 4 to the front of the anaerobic tank 2, with the ratio of reflux flow rate to influent flow rate being the reflux ratio R1; reflux 2 is as follows: reflux from the end of the aerobic tank 5 to the front of the pre-anoxic tank 4, with the ratio of reflux flow rate to influent flow rate being the reflux ratio R2; reflux 3 is as follows: when the membrane tank uses blower 8 for aeration, reflux from the end of membrane tank 9 to the front of the aerobic tank 5, with the ratio of reflux flow rate to influent flow rate being the reflux ratio R3; when the membrane tank uses vibrating motor 11, reflux from the end of membrane tank 9 to the front of the pre-anoxic tank 4, with the ratio of reflux flow rate to influent flow rate being the reflux ratio R3. The sludge property improvement unit 13 has an inlet, a return outlet, and a sludge discharge outlet. The sludge property improvement unit 13 is connected to the MBR membrane tank 9 through the inlet and return outlet. The inlet of the feed pump 12 is located in the return channel of the MBR membrane tank 9, the return outlet is located in the water distribution channel of the MBR membrane tank 9, and the sludge discharge outlet is located before the excess sludge discharge pump. The sludge property improvement unit 13 is equipped with an intelligent control module that adjusts operating parameters, including feed flow rate, sludge discharge ratio, and operating time, in real time based on information such as influent and effluent water quality and sludge concentration.

[0043] In this embodiment, the sludge property improvement unit 13 is connected to the MBR membrane tank 9 through an inlet and a return outlet. Excess sludge from the MBR unit is discharged through the sludge discharge outlet of the sludge property improvement unit, replacing the conventional sludge discharge method of the MBR unit. Online sludge concentration (MLSS) meters and water quality monitoring instruments are installed in the influent and MBR membrane tank 9 to monitor sludge concentration and effluent water quality. Combined with the influent water quality, a suitable range for sludge concentration in the MBR unit is determined.

[0044] In this embodiment, specifically, the sludge property improvement unit 13 is equipped with an intelligent control module. A pressure gauge and a flow meter are installed at the feed inlet, and an online MLSS meter and a flow meter are installed at the sludge discharge outlet. Based on the concentration effect of the sludge property improvement unit 13, the operating parameters of the sludge property improvement unit 13, including the feed inlet flow rate and the sludge discharge outlet flow rate, are adjusted in real time to maintain a stable concentration and separation effect. Based on the influent and effluent water quality and sludge concentration, the operating time of the sludge property improvement unit 13 is adjusted in real time to control the sludge concentration in the membrane tank and effectively prevent membrane fouling.

[0045] The sludge property improvement unit 13 increases the MLVSS / MLSS ratio of the MBR unit at the return port, enabling the system to operate at low sludge concentration. At the sludge discharge port, sludge thickening and inorganic matter enrichment are achieved. New water plants may not need to design sludge thickeners, and existing water plants can surpass their sludge thickeners. Furthermore, it can reduce the moisture content of the remaining sludge at the effluent or reduce the dosage of sludge dewatering agents, thereby reducing investment and operating costs.

[0046] In this embodiment, the sludge activation and reduction method using the above-mentioned modified MBR system includes the following steps:

[0047] 1) After pretreatment, the wastewater to be treated enters anaerobic tank 2 and is mixed with sludge. Under anaerobic stirring conditions, it stays for 1-3 hours with MLSS of 3-5 g / L.

[0048] 2) The sludge mixture from anaerobic tank 2 is pushed into pre-anoxic tank 4 and held for 4-6 hours under stirring conditions, with MLSS of 6-8 g / L.

[0049] 3) The sludge mixture from the pre-anoxic tank 4 is pushed into the aerobic tank 5 and stays for 4-6 hours under aeration and oxygenation conditions. The DO concentration in the aeration zone of the aerobic tank is 0.5-2 mg / L and the MLSS is 8-10 g / L.

[0050] 4) The sludge mixture from aerobic tank 5 is pushed into anoxic tank 7 and held for 3-4 hours under stirring conditions, with MLSS of 8-10 g / L.

[0051] 5) The sludge mixture from the post-anoxic tank 7 is pushed into the membrane tank 9, where it stays for 1.5 hours. The MLSS is 12-15 g / L. The membrane tank separates the sludge and water by pumping the permeate.

[0052] 6) The reflux ratio R1 is 100%-200%, the reflux ratio R2 is 200%-600%, when the membrane tank 9 uses the blower 8 to aerate and control membrane fouling, the reflux ratio R3 is 400%-500%, and when the membrane tank uses the vibrating motor 11 to control membrane fouling, the reflux ratio R3 is 200%-300%.

[0053] 7) The sludge mixed liquor from MBR membrane tank 9 is pumped into sludge property improvement unit 13 through the feed inlet located in the return channel of MBR membrane tank 9. The sludge from the return inlet returns to the water distribution channel of MBR membrane tank 9, and the remaining sludge is discharged from the sludge discharge outlet. The daily sludge discharge volume is determined by calculation based on the influent and effluent water quality and the sludge concentration in the membrane tank. The calculation process is as follows:

[0054]

[0055] Where TSS represents the total sludge volume, in kg; Q 设 Indicates the design influent flow rate, m 3 / h; HRT 膜 HRT 后 HRT 好 HRT 前 HRT 厌 The design hydraulic retention times (in hours) for the membrane tank, post-anoxic tank, aerobic tank, pre-anoxic tank, and anaerobic tank are respectively; MLSS 膜 This indicates the sludge concentration in the membrane tank, in g / L.

[0056]

[0057] Where EAS represents the amount of residual sludge, in kg; TN 进 TN 出 These represent the total nitrogen monitoring values ​​for influent and product water, respectively, in mg / L; These represent the ammonia nitrogen monitoring values ​​for influent and product water, respectively, in mg / L; TN 设 This indicates the set value for total nitrogen in the produced water, in mg / L; This indicates the set value for ammonia nitrogen in the produced water, in mg / L.

[0058] The remaining sludge is discharged through the sludge discharge port of sludge property improvement unit 13, according to the MLSS of the sludge discharge port. 排 and its relationship with MBR membrane pool 9MLSS 膜 Adjust the MLSS concentration ratio (MLSS factor) to control the feed and discharge flow rates. The discharge flow rate should be 5%-15% of the unit's feed flow rate to ensure adequate MLSS concentration at the discharge port. 排 The concentration ratio is between 1.4 and 4 times, while the inlet pressure is controlled within a safe and economical range (≤0.3MPa).

[0059] Furthermore, based on the MLSS of the sludge discharge port 排 Calculate and control the operating time of the sludge property improvement unit (13) based on EAS and sludge discharge flow rate:

[0060]

[0061] Where T represents the operating time of the sludge property improvement unit, in hours; MLSS 排Q indicates the sludge concentration at the sludge discharge point, in g / L; 排 The flow rate at the sludge discharge outlet is expressed in m. 3 / h.

[0062] In one specific embodiment, during operation of the modified MBR system, the MBR unit is inoculated with ordinary activated sludge from a wastewater treatment plant. The MBR unit has a treatment capacity of 8,000-10,000 tons / day, a hydraulic retention time (HRT) of 18-22 hours, and the membrane tank is aerated using blowers. The MLSS concentration in the membrane tank is 12-15 g / L, and the initial MLVSS / MLSS ratio is 0.43-0.45. The sludge activation modification unit is connected to the membrane tank through an inlet and an overflow outlet, and the feed pump has a feed flow rate of 50-60 m³ / h. 3 / h, intermittent operation, inlet flow rate set to 50-60m³ / h 3 The sludge discharge flow rate is 5%-15% of the feed flow rate, and the daily sludge discharge operation time is 8-16 hours. After nearly two months of continuous operation, the residual sludge concentration ratio at the discharge port is 1.4-4 times, the MLVSS / MLSS is 15%-25% lower than the feed, and the MBR unit's MLVSS / MLSS is increased to 0.52-0.55. After treatment by the original dewatering system, the moisture content of the transported sludge is reduced by 5%-10%, the blower energy consumption is reduced by about 10%, and the overall operating cost is reduced by about 5%-10%.

[0063] In summary, the improved MBR system and operation method described in this embodiment of the invention include an MBR unit and a sludge property improvement unit connected by pipelines. Wastewater, after pretreatment, enters the MBR unit. The sludge mixture is pumped into the sludge property improvement unit from the inlet via a feed pump. At the return outlet, the MLVSS / MLSS ratio of the MBR unit is increased, enabling the system to operate with low sludge concentration. This helps improve system aeration efficiency while reducing membrane fouling rate. At the sludge discharge outlet, sludge thickening and inorganic matter enrichment are achieved. New water plants may not need to design sludge thickeners, and existing water plants can surpass their existing sludge thickeners. Furthermore, it can reduce the moisture content of residual sludge at the effluent or reduce the dosage of sludge dewatering agents, thereby reducing investment and operating costs. The system determines the sludge discharge volume of the sludge property improvement unit based on influent and effluent water quality and sludge concentration. The sludge property improvement unit adjusts its operating parameters, including feed flow rate, sludge discharge ratio, and operating time, in real time based on the sludge discharge volume and sludge concentration. The sludge property improvement unit is equipped with an intelligent control module. A pressure gauge and flow meter are installed at the feed inlet, and an online MLSS meter and flow meter are installed at the discharge outlet. Based on the concentration effect of the sludge property improvement unit, the operating parameters of the sludge property improvement unit, including the feed inlet flow rate and the discharge outlet flow rate, are adjusted in real time to maintain a stable concentration and separation effect. Based on the influent and effluent water quality and sludge concentration, the operating time of the sludge property improvement unit is adjusted in real time to control the sludge concentration in the membrane tank and effectively prevent membrane fouling.

[0064] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions disclosed in the present invention, various modifications or variations that can be made by those skilled in the art without creative effort should be included within the scope of protection of the present invention.

Claims

1. A membrane bioreactor system, characterized in that, include: The membrane bioreactor unit and the sludge property improvement unit are connected by pipelines; wherein, the membrane bioreactor unit includes an anaerobic tank (2), a pre-anoxic tank (4), an aerobic tank (5), a post-anoxic tank (7) and a membrane tank (9) arranged in sequence; Agitators (3) are provided in the anaerobic tank (2), the pre-anoxic tank (4) and the post-anoxic tank (7); an aerator (6) is provided in the aerobic tank (5); and a membrane module (10) is provided in the membrane tank (9). The sludge property improvement unit (13) is provided with a feed inlet, a return outlet and a sludge discharge outlet. The sludge property improvement unit (13) is connected to the membrane tank (9) through the feed inlet and the return outlet. The feed inlet of the feed pump (12) is set in the return channel of the membrane tank (9), the return outlet is set in the water distribution channel of the membrane tank (9), and the sludge discharge outlet is set at the front end of the residual sludge discharge pump. The sludge property improvement unit (13) is equipped with an intelligent control module, which adjusts the operating parameters of the sludge property improvement unit (13) in real time according to the concentration effect of the sludge property improvement unit (13); a pressure gauge and a flow meter are installed at the feed inlet, and an online sludge concentration meter and a flow meter are installed at the discharge outlet.

2. The membrane bioreactor system according to claim 1, characterized in that, The membrane tank (9) uses a blower (8) for aeration to control membrane fouling, and the air-to-water ratio in the membrane tank is 6-10.

3. The membrane bioreactor system according to claim 2, characterized in that, The flow rate from the end of the pre-anoxic tank (4) is returned to the front end of the anaerobic tank (2), and the ratio of the return flow rate to the influent flow rate is the return ratio R1; the flow rate from the end of the aerobic tank (5) is returned to the front end of the pre-anoxic tank (4), and the ratio of the return flow rate to the influent flow rate is the return ratio R2; when the membrane tank is aerated by a blower (8), the flow rate from the end of the membrane tank (9) is returned to the front end of the aerobic tank (5), and the ratio of the return flow rate to the influent flow rate is the return ratio R3.

4. The membrane bioreactor system according to claim 1, characterized in that, The membrane tank (9) uses a vibrating motor (11) to control membrane fouling; the membrane module (10) uses the vibrating motor (11) to achieve horizontal reciprocating motion with a vibration frequency of 0.5-1Hz and an amplitude of 5-10cm.

5. The membrane bioreactor system according to claim 4, characterized in that, The flow rate from the end of the pre-anoxic tank (4) back to the front of the anaerobic tank (2) is the ratio of the return flow rate to the influent flow rate as the return ratio R1; the flow rate from the end of the aerobic tank (5) back to the front of the pre-anoxic tank (4) is the ratio of the return flow rate to the influent flow rate as the return ratio R2; when the membrane fouling is controlled by the vibrating motor (11), the flow rate from the end of the membrane tank (9) back to the front of the pre-anoxic tank (4) is the ratio of the return flow rate to the influent flow rate as the return ratio R3.

6. The membrane bioreactor system according to claim 1, characterized in that, The membrane tank (9) is equipped with an online sludge concentration meter and a water quality monitoring instrument to monitor the sludge concentration, influent water quality and effluent water quality, thereby determining the appropriate range of sludge concentration in the MBR unit.

7. A method for sludge activation and reduction using a membrane bioreactor system as described in any one of claims 1-6, characterized in that, include: After pretreatment, the wastewater to be treated enters the anaerobic tank (2) and mixes with the sludge, and remains under anaerobic stirring conditions; The sludge mixture from the anaerobic tank (2) is pushed into the pre-anoxic tank (4) and remains under stirring conditions; the sludge mixture from the pre-anoxic tank (4) is pushed into the aerobic tank (5) and remains under aeration conditions; the sludge mixture from the aerobic tank (5) is pushed into the post-anoxic tank (7) and remains under stirring conditions; the sludge mixture from the post-anoxic tank (7) is pushed into the membrane tank (9) and remains there. The membrane tank separates sludge and water by pumping permeate; the sludge mixture from the membrane tank (9) is pumped into the sludge property improvement unit (13) through the feed inlet located in the return channel of the membrane tank (9). The sludge from the return inlet returns to the water distribution channel of the membrane tank (9), and the remaining sludge is discharged from the sludge discharge outlet. The daily sludge discharge volume is determined by calculation based on the influent and effluent water quality and the sludge concentration in the membrane tank; the remaining sludge is discharged through the sludge discharge outlet of the sludge property improvement unit (13), according to the MLSS of the sludge discharge outlet. 排 and its relationship with MBR membrane pool (9) MLSS 膜 Adjust the feed flow rate and sludge discharge flow rate accordingly. The sludge discharge flow rate should be 5%-15% of the feed flow rate of this unit to ensure MLSS at the sludge discharge port. 排 The concentration ratio is between 1.4 and 4 times, while controlling the inlet pressure within a safe and economical range; based on the MLSS at the discharge port... 排 The operating time of the sludge property improvement unit (13) is calculated and controlled by EAS and sludge discharge flow rate.

8. The sludge activation and reduction method according to claim 7, characterized in that, The reflux ratio R1 is 100%-200%, the reflux ratio R2 is 200%-600%, when the membrane tank (9) uses a blower (8) to aerate and control membrane fouling, the reflux ratio R3 is 400%-500%, and when the membrane tank uses a vibrating motor (11) to control membrane fouling, the reflux ratio R3 is 200%-300%.

9. The sludge activation and reduction method according to claim 7, characterized in that, The formula for calculating daily sludge discharge volume is as follows: Where TSS represents the total sludge volume; Q 设 Indicates the design influent flow rate; HRT 膜 HRT 后 HRT 好 HRT 前 HRT 厌 These represent the design hydraulic retention times (MLSS) for the membrane tank, post-anoxic tank, aerobic tank, pre-anoxic tank, and anaerobic tank, respectively. 膜 Indicates the sludge concentration in the membrane tank; EAS represents the amount of excess sludge; TN 进 TN 出 These represent the total nitrogen monitoring values ​​for influent and product water, respectively. These represent the ammonia nitrogen monitoring values ​​for influent and product water, respectively; TN 设 This indicates the set value for total nitrogen in the produced water; This indicates the set value for ammonia nitrogen in the produced water.

10. The sludge activation and reduction method according to claim 7, characterized in that, According to the MLSS of the sludge discharge port 排 Calculate and control the operating time of the sludge property improvement unit (13) based on EAS and sludge discharge flow rate: Where T represents the operating time of the sludge property improvement unit; MLSS 排 Indicates the sludge concentration at the sludge discharge outlet; Q 排 This indicates the flow rate at the sludge discharge outlet.

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