Double-layer aeration system for preventing MBR (membrane bioreactor) double-layer component membrane pool from wire breakage and sludge deposition

Abstract

The invention discloses a double-layer aeration system for preventing wire breakage and sludge deposition of an MBR double-layer component membrane pool, which comprises a raw water pool, a raw water inlet peristaltic pump, an MBR double-layer component membrane pool, a perforated aeration pipe, a pulse aeration box, an aeration pump, a gas meter, a water outlet gear pump, an ultrafiltration membrane component, a pressure sensor, a transmembrane pressure difference display, a sludge discharge peristaltic pump and a water outlet pool, the MBR double-layer assembly membrane pool comprises a first MBR membrane assembly and a second MBR membrane assembly, the first MBR membrane assembly and the second MBR membrane assembly are arranged in parallel, and the perforated aeration pipe and the pulse aeration box are configured to be used as aeration assemblies of the first MBR membrane assembly and the second MBR membrane assembly. According to the invention, the membrane is physically scrubbed by utilizing different aeration modes and a double-layer aeration mode, so that the phenomena of membrane pollution, sludge accumulation and wire breakage are effectively relieved, a reliable theoretical basis is provided for transforming an MBR membrane tank into a double-layer aeration mode in a water purification plant using the MBR hollow fiber membrane, and meanwhile, the method has important significance on reducing pollution and carbon.

Description

Technical Field

[0001] The present invention relates to the technical field of water purification, and particularly to a water purification device for improving the utilization efficiency of an MBR membrane module, specifically a double-layer aeration system for preventing filament breakage and sludge accumulation in the membrane pool of an MBR double-layer module. Background Art

[0002] The application of the membrane bioreactor (MBR) process can provide important support for municipal sewage treatment. MBR is an advanced sewage treatment technology that combines the advantages of a bioreactor and membrane separation technology, and can efficiently remove organic matter, suspended solids, and microorganisms in sewage. However, problems such as membrane fouling inevitably occur during long-term operation, and its influencing factors and formation are complex. The main sources include organic matter in water bodies (such as humic acid, protein, polysaccharide, etc.), microorganisms (extracellular polymeric substances EPS on the cell surface and released soluble microorganisms SMP), and calcium scale inorganic substances.

[0003] To address the problem of membrane fouling during the water treatment process, systematically carrying out membrane fouling control, simultaneously reducing the operating energy consumption of the MBR process, and reducing the operating cost are important ways to implement the work of reducing carbon emissions and deeply fight the tough battle of pollution prevention and control, and help enterprises achieve green, low-carbon, and high-quality development.

[0004] Aeration purging is an important means to control membrane fouling. Constructing a precise regulation and control strategy for pollution control through aeration purging is beneficial to reducing aeration energy consumption and improving the stability and high efficiency of the membrane. Currently, in the single-layer aeration mode, the lower membrane filaments are prone to filament breakage, and the upper membrane filaments are prone to sludge accumulation, increasing the operating cost of the water purification plant.

[0005] The typical prior art CN209468274U discloses an automatic control dual-membrane reciprocal flushing sewage treatment device based on the MBR membrane process, which realizes water production or dual-membrane reciprocal flushing by opening or closing the water production pipe according to a predetermined program; a pressure sensor, a self-priming pump, and a security filter electrically connected to the automatic controller are installed in the equipment room. Through the pressure signal of the pressure sensor, the backwashing operation is started, and the corresponding group of membranes can be automatically switched to the valve for backwashing, and at the same time, bleaching water is added to clean the membrane filaments. By adopting an automatically controllable dual-membrane reciprocal flushing method to clean the MBR membrane, the service life of the membrane is extended, and the operating cost of the MBR membrane is reduced. However, in fact, the above process still does not carry out layered aeration during the aeration process, and it is inevitable that the lower layer has filament breakage while the upper layer is prone to sludge accumulation, resulting in the problem that the membrane is not fully utilized.

[0006] CN220012320U discloses a membrane bioreactor device with dual-mode operation, including a biochemical tank group, a membrane tank, and a control module. The biochemical tank group includes multiple biotreatment tanks arranged in parallel. Each biotreatment tank includes an anaerobic tank, an anoxic tank, and an aerobic tank connected to each other. A downward-opening adjustable weir gate is provided at the water outlet of the aerobic tank. In the MBR mode, the downward-opening adjustable weir gate in at least one of the biotreatment tanks in the biochemical tank group is at a high point, and water is continuously supplied to the membrane tank in a high liquid level state. In the submerged ultrafiltration mode, each biotreatment tank in the biochemical tank group alternately supplies water to the membrane tank. Each biotreatment tank operates periodically. In the water outlet stage of each cycle, the downward-opening adjustable weir gate in the biotreatment tank moves from a high point to a low point. The purpose is to operate in a periodic replacement mode to improve the operation efficiency of the membrane device.

[0007] The inventor redistributed the current aeration intensity of a water purification plant in Guangzhou, added an intermediate aeration module to the single-layer aeration of the MBR double-layer membrane tank, and on this basis, studied membrane pollution control, sludge accumulation and filament breakage phenomena, and the operation energy consumption of the MBR process. Under the action of bottom pulse aeration boxes and intermediate perforated aeration pipes in the MBR double-layer module membrane tank, the rate of membrane pollution accumulation slows down, the phenomena of sludge accumulation and filament breakage decrease, the operation and maintenance cost of the MBR process is reduced, and the water quality is the same as that of single-layer aeration, meeting the first-class A treatment standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002). Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a double-layer aeration system for preventing filament breakage and sludge accumulation in an MBR double-layer module membrane tank. To solve the above technical problem, the present invention discloses the following technical solutions: In a first aspect, the present application provides a double-layer aeration system for preventing filament breakage and sludge accumulation in an MBR double-layer module membrane tank, including a raw water tank, a raw water inlet peristaltic pump, an MBR double-layer module membrane tank, a perforated aeration pipe, a pulse aeration box, an aeration pump, a gas flow meter, an outlet gear pump, an ultrafiltration membrane module, a pressure sensor, a transmembrane pressure difference display, a sludge discharge peristaltic pump, and an outlet tank.

[0009] Further, the MBR double-layer module membrane tank includes a first MBR membrane module and a second MBR membrane module. The first MBR membrane module and the second MBR membrane module are arranged in parallel. The perforated aeration pipe and the pulse aeration box are configured as aeration components for the first MBR membrane module and the second MBR membrane module.

[0010] Further, the MBR double-layer module membrane tanks are arranged in parallel, and the number of the MBR double-layer module membrane tanks is at least two.

[0011] Further, the raw water tank is connected to the raw water inlet peristaltic pump and the MBR double-layer module membrane tank through pipelines, and the MBR double-layer module membrane tank is connected to the ultrafiltration membrane module.

[0012] Further, the water outlet tank is connected to the ultrafiltration membrane module through a water outlet gear pump and a pressure sensor.

[0013] Further, pressure sensors are provided in both the first MBR membrane module and the second MBR membrane module in the MBR double-layer module membrane tank. The first MBR membrane module and the second MBR membrane module are vertically arranged, and the first MBR membrane module is located in the vertical direction of the second MBR membrane module. The aeration intensity of the first MBR membrane module and the second MBR membrane module is less than 0.1 m 3 / m 2 •h.

[0014] Further, the pressure sensor is installed at the pipeline outlet of the ultrafiltration membrane module and is connected to a transmembrane pressure difference display.

[0015] Further, the pressure sensor transmits signals to the display. The display respectively shows the transmembrane pressure differences of the effluents of the upper and lower layers of the ultrafiltration membrane module. The aeration of the upper and lower layers is respectively controlled by an aeration pump, and the aeration intensity is controlled by a gas flow meter in the pipeline.

[0016] Further, at least one bent portion is provided at the end of the perforated aeration pipe.

[0017] Further, the ultrafiltration membrane module includes a plurality of parallel hollow fiber membranes and a water outlet connecting the hollow fiber membranes. The ultrafiltration membrane module is arranged inside the MBR double-layer module membrane tank.

[0018] Further, the aeration pump is connected to the perforated aeration pipe and / or the pulse aeration box through a gas flow meter to achieve double-layer aeration.

[0019] Further, the aeration intensity of the double-layer aeration of the first MBR membrane module + the second MBR membrane module is 0.04 (upper) + 0.08 (lower) m 3 / m 2 •h in a distribution manner.

[0020] Further, the aeration intensity of the double-layer aeration of the first MBR membrane module + the second MBR membrane module is 0.06 (upper) + 0.06 (lower) m 3 / m 2 •h in a distribution manner.

[0021] Further, there are hollow fiber membranes in the ultrafiltration membrane module. The hollow fiber membranes are connected to the raw water inlet, and the water filtered by the membrane flows out through the pipeline water outlet.

[0022] Further, the water outlet tank is connected to an external sludge tank through the sludge discharge port at the bottom of the MBR double-layer module membrane tank, which is used to regularly discharge the self-growth amount of sludge. The water outlet tank is connected to the MBR double-layer module membrane tank through a sludge discharge peristaltic pump. By discharging the mixed liquid of mud and water in the MBR double-layer module membrane tank device, the sludge concentration in the double layers of the MBR double-layer module membrane tank is maintained.

[0023] Further, the working process of the present invention is as follows: The raw water in the raw water inlet channel of the MBR membrane tank enters the MBR double-layer module membrane tank device from the raw water tank under the action of the raw water inlet peristaltic pump. The self-made ultrafiltration membrane module uses PVDF hollow fiber membranes. The hollow fiber membranes are placed vertically in the device. The filtered water enters the membrane module under the action pressure of the water outlet gear pump and flows to the water outlet tank through the membrane module outlet pipe.

[0024] A pressure sensor is provided at the membrane module outlet pipe and is connected to a transmembrane pressure difference display. The transmembrane pressure difference data collected by the transmembrane pressure difference display is used to judge the membrane fouling situation of the membrane module, and chemical cleaning is carried out regularly.

[0025] The raw water flows into the MBR double-layer module membrane tank under the action of the raw water inlet peristaltic pump. The ultrafiltration membrane module is placed vertically in the MBR double-layer module membrane tank device. Under the suction action of the water outlet gear pump on the hollow fiber membranes, the filtered water enters the cavity inside the hollow fiber membranes, flows out through the water outlet, and then flows to the pressure sensor. The pressure sensor is connected to the transmembrane pressure difference display, and the transmembrane pressure difference display collects the transmembrane pressure difference parameters monitored by the pressure sensor.

[0026] In a second aspect, the present application provides a water treatment method, specifically, a water treatment method is adopted using a double-layer aeration system for preventing filament breakage and mud accumulation in an MBR double-layer module membrane tank provided in the first aspect.

[0027] By adopting the above technical solutions, the present invention has the following technical effects: The present invention uses the double-layer aeration device of the double-layer module membrane tank to treat the raw water in the raw water inlet channel of the MBR membrane tank, and uses double-layer aeration to scrub the double layers of the module, which has a good effect of slowing down the pollution accumulation speed on the membrane surface and effectively reduces the operation and maintenance cost of the MBR process.

[0028] During the operation of the device of the present invention, the total aeration intensity is redistributed, reducing the phenomenon of filament breakage in the lower layer of membrane filaments and mud accumulation in the upper layer of membrane filaments; during the operation of the device of the present invention, a pressure sensor is combined with a transmembrane pressure difference display terminal, which can real-time monitor the change of transmembrane pressure difference and can realize automatic management.

[0029] I. When the sludge concentration is in the range of 6000 - 8000 mg / L, on the premise of ensuring that the effluent quality meets the Class A standard of "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918 - 2002), the aeration intensity combination is 0.04 (upper) + 0.08 (lower) m 3 / (m 2 •h). The increase in the transmembrane pressure difference of the upper and lower layer membrane filaments after three days of operation is 0.5 kPa and 0.5 kPa respectively, both of which are less than that of single - port aeration in the lower layer (the aeration intensity is 0.12 m 3 / (m 2 •h)). The increase in the transmembrane pressure difference of the upper and lower layer membrane filaments of single - port aeration in the lower layer after three days of operation is 0.9 kPa and 0.7 kPa. And for the double - layer aeration form, the sludge accumulation on the upper - layer membrane filaments is less than that of single - port aeration in the lower layer, and there is no filament breakage in the lower - layer membrane filaments.

[0030] II. In the long - term experiment, the sludge concentration was increased, that is, when the sludge concentration was in the range of 14000 - 15000 mg / L, on the premise of ensuring that the effluent quality meets the Class A standard of "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918 - 2002), the aeration intensity combination was 0.04 (upper) + 0.08 (lower) m 3 / (m 2 •h). The increase in the transmembrane pressure difference of the upper and lower layer membrane filaments after nine days of operation was 25.2 kPa and 24.6 kPa respectively, both of which were less than that of single - port aeration in the lower layer (the aeration intensity was 0.12 m 3 / (m 2 •h)). The increase in the transmembrane pressure difference of the upper and lower layer membrane filaments of single - port aeration in the lower layer after three days of operation was 30.2 kPa and 26.8 kPa. And for the double - layer aeration form, the sludge accumulation on the upper - layer membrane filaments was less than that of single - port aeration in the lower layer, and there was no filament breakage in the lower - layer membrane filaments. Description of the Drawings

[0031] Figure 1 、 One Schematic diagram of a double - layer aeration system for preventing filament breakage and sludge accumulation in the MBR double - layer module membrane tank; Figure 2 、Schematic diagram of the ultrafiltration membrane module structure; Figure 3 、Physical diagram of a double - layer aeration system for preventing filament breakage and sludge accumulation in the MBR double - layer module membrane tank of a certain embodiment; Figure 4 、0.12 m 3 / m 2 •h single - port aeration mode in the lower layer and 0.04 (upper) + 0.08 (lower) m 3 / m 2 •h layer - distributed double - layer aeration mode transmembrane pressure difference change diagram (three - day short - term test); Figure 5, 0.12 m 3 / m 2 • h Lower single - port aeration mode and 0.04 (upper) + 0.08 (lower) m 3 / m 2 • h Trans - membrane pressure difference change diagram of layer - distributed double - layer aeration mode (ten - day long - term test); Figure 6 , 0.12 m 3 / m 2 • h Lower single - port aeration mode and 0.06 (upper) + 0.06 (lower) m 3 / m 2 • h Trans - membrane pressure difference change diagram of layer - distributed double - layer aeration mode (30 - day periodic test); Figure 7 , 0.12 m 3 / m 2 • h Lower single - port aeration mode and 0.06 (upper) + 0.06 (lower) m 3 / m 2 • h Power consumption comparison diagram of layer - distributed double - layer aeration mode (30 - day periodic test); Figure 8 , Comparison diagram of sludge accumulation on upper membrane filaments under different aeration intensity conditions (low - concentration three - day short - term test); Figure 9 , Comparison diagram of sludge accumulation on upper membrane filaments under different aeration intensity conditions (high - concentration three - day short - term test); Figure 10 , Comparison diagram of sludge accumulation on upper membrane filaments under different aeration intensity conditions (high - concentration ten - day long - term test).

[0032] In the figure: Raw water tank 1, Raw water inlet peristaltic pump 2, MBR double - layer module membrane tank 3, Perforated aeration pipe 4, Pulse aeration box 5, Aeration pump 6, Gas flow meter 7, Effluent gear pump 8, Ultra - filtration membrane module 9, Hollow fiber membrane 901, Outlet 902, Pressure sensor 10, Trans - membrane pressure difference display 11, Sludge discharge peristaltic pump 12, Effluent tank 13. Detailed implementation manners

[0033] The following further describes the detailed implementation manners of the present invention with reference to the accompanying drawings. It should be noted here that the description of these implementation manners is for helping to understand the present invention, but does not constitute a limitation to the present invention. In addition, the technical features involved in the various implementation manners of the present invention described below can be combined with each other as long as they do not conflict with each other. Example 1

[0034] Please refer to Figures 1 - 10, the present invention provides a technical solution: a double-layer aeration system for preventing filament breakage and sludge accumulation in the membrane tank of an MBR double-layer component, including a raw water tank (1), a raw water inlet peristaltic pump (2), an MBR double-layer component membrane tank (3), a perforated aeration pipe (4), a pulsed aeration box (5), an aeration pump (6), a gas flow meter (7), an effluent gear pump (8), an ultrafiltration membrane module (9), a pressure sensor (10), a transmembrane pressure difference display (11), a sludge discharge peristaltic pump (12), and an effluent tank (13).

[0035] Among them, the raw water in the MBR membrane tank inlet channel is stored in the raw water tank (1). Under the transportation of the raw water inlet peristaltic pump (2), the raw water flows into the MBR double-layer component membrane tank (3), and during this process, the raw water contacts the hollow fiber membrane of the ultrafiltration membrane module. Then, the water in the ultrafiltration membrane module flows through the pressure sensor (10) under the action of the effluent gear pump (8) and finally flows into the effluent tank (13).

[0036] Among them, the MBR double-layer component membrane tank (3) includes a first MBR membrane module and a second MBR membrane module. The first MBR membrane module and the second MBR membrane module are arranged vertically in the MBR double-layer component membrane tank (3). The first MBR membrane module is vertically arranged above the second MBR membrane module. The first MBR membrane module and the second MBR membrane module are arranged in parallel. The perforated aeration pipe (4) and the pulsed aeration box (5) are configured for aeration of the first MBR membrane module and the second MBR membrane module. The perforated aeration pipe (4) is arranged between the first MBR membrane module (3) and the second MBR membrane module. The pulsed aeration box (5) is located at the bottom of the second MBR membrane module. Pressure sensors (10) are provided for both the first MBR membrane module (3) and the second MBR membrane module and are both located in the MBR double-layer component membrane tank. The aeration intensity of the first MBR membrane module and the second MBR membrane module is less than 0.1 m 3 / m 2 •h. The aeration intensity ratio of the double-layer aeration of the first MBR membrane module + the second MBR membrane module is 1:2; in this embodiment, the aeration intensity of the double-layer aeration of the first MBR membrane module + the second MBR membrane module is 0.04 (upper) + 0.08 (lower) m 3 / m 2 •h distribution method.

[0037] The pressure sensor (10) is installed at the pipe outlet of the ultrafiltration membrane module (9) and is connected to the transmembrane pressure difference display (11).

[0038] The pressure sensor (10) transmits the signal to the display, and the display respectively shows the transmembrane pressure difference of the effluent of the upper and lower ultrafiltration membrane modules. The upper and lower layer aerations are respectively controlled by the aeration pump (6), and the aeration intensity is controlled by the gas flow meter (7) in the pipeline.

[0039] The end of the perforated aeration pipe (4) has a bent portion.

[0040] The ultrafiltration membrane module (9) includes a number of hollow fiber membranes (901) connected in parallel and a water outlet (902) connecting the hollow fiber membranes. The ultrafiltration membrane module is arranged inside the MBR double-layer module membrane tank (3).

[0041] The aeration pump (6) is connected to the perforated aeration pipe (4) and / or the pulse aeration box (5) through a gas flow meter to achieve double-layer aeration.

[0042] The water outlet tank (13) is connected to an external sludge tank through the bottom sludge discharge port of the MBR double-layer module membrane tank (3) for regularly discharging the self-growth amount of sludge. The water outlet tank is connected to the MBR double-layer module membrane tank (3) through a sludge discharge peristaltic pump (12). By discharging the sludge-water mixture in the MBR double-layer module membrane tank (3), the sludge concentration in the MBR double-layer module membrane tank (3) is maintained.

[0043] The aeration intensity of the double-layer aeration is 0.04 (upper) + 0.08 (lower) m 3 / m 2 •h distribution method. Experiments were carried out on the raw water in the inlet channel of the membrane tank for three days (short-term) and ten days (long-term) within the range of sludge concentration of 6000 - 8000 mg / L and 14000 - 15000 mg / L.

[0044] The method includes the following steps: 1) Extract the raw water in the inlet channel of the membrane tank to the raw water bucket and add it to the first and second MBR double-layer module membrane tanks by using the inlet peristaltic pump; 2) Use the outlet gear pump for suction. The pressure sensor and the transmembrane pressure difference display detect the change of the transmembrane pressure difference. The sludge discharge peristaltic pump is turned on at the same time to maintain the sludge concentration in the membrane tank; 3) During this period, samples are taken from the upper layer for water quality detection, such as turbidity, ammonia nitrogen, COD cr etc.; 4) After the experiment, empty the raw water in the membrane tank and record the sludge accumulation phenomenon on the upper layer of the membrane filaments and the filament breakage phenomenon on the lower layer of the membrane filaments.

[0045] For specific results, please refer to the attached Figure 4 、 5 、8, 9 and 10. Example 2

[0046] The main difference between Example 3 and Example 1 is that: the aeration intensity ratio of the double-layer aeration of the first MBR membrane module + the second MBR membrane module is 1:1; the aeration intensity of the double-layer aeration of the first MBR membrane module + the second MBR membrane module is 0.06 (upper) + 0.06 (lower) m3 / m 2 • Distribution method of h.

[0047] Perform a periodic experiment on the raw water in the inlet channel of the membrane treatment tank for 30 days.

[0048] The method includes the following steps: 1) Extract the raw water in the inlet channel of the membrane treatment tank into the raw water bucket, and use the inlet peristaltic pump to add it into the first and second MBR double-layer module membrane treatment tanks; 2) Use the outlet gear pump for suction. The pressure sensor and transmembrane pressure difference display detect the change of transmembrane pressure difference, and the sludge discharge peristaltic pump is turned on at the same time to maintain the sludge concentration in the membrane treatment tank; 3) During this period, take samples along the upper layer for water quality detection, such as turbidity, ammonia nitrogen, CODcr, etc. Use a temperature, pressure and flow detector to detect the wind pressure and air volume parameters at the outlet of the aeration pump and the air inlet of the aeration module, and calculate the power consumption; 4) Perform maintenance cleaning every 3 days with a sodium hypochlorite solution concentration of 200 - 300 ppm, that is, use the outlet gear pump to reverse the solution into the inside of the membrane filaments for backwashing; 5) The maintenance cleaning plan in step 4) is as follows: In the first stage, use a sodium hypochlorite solution with a concentration of 200 - 300 ppm to reverse it into the inside of the membrane filaments, with a chemical addition time of 300 s, a standing time of 240 s, and an aeration time of 180 s. In the second stage, use a sodium hypochlorite solution with a concentration of 200 - 300 ppm to reverse it into the inside of the membrane filaments, with a chemical addition time of 30 s, a standing time of 240 s, and an aeration time of 30 s, and repeat 8 times; 4) After the experiment, drain the raw water in the membrane treatment tank, and record the sludge accumulation phenomenon on the upper layer of the membrane filaments and the filament breakage phenomenon on the lower layer of the membrane filaments.

[0049] For specific results, please refer to the attached Figure 6 and 7 . Comparative Example 1

[0050] A method for purifying water using an MBR double-layer module membrane treatment tank. The MBR double-layer module membrane treatment tank only has aeration from the bottom pulse aeration box (5). In the range of sludge concentration of 6000 - 8000 mg / L and 14000 - 15000 mg / L, it is controlled by one aeration pump, and the aeration intensity of the bottom pulse aeration box is 0.12 m 3 / m 2 •h, and experiments on the raw water in the inlet channel of the membrane treatment tank were carried out for three days (short-term) and ten days (long-term).

[0051] 1) Extract the raw water in the inlet channel of the membrane treatment tank into the raw water bucket, and use the inlet peristaltic pump to add it into the first and second MBR double-layer module membrane treatment tanks; 2) Use the effluent gear pump for suction. The pressure sensor and the transmembrane pressure difference display detect the change of the transmembrane pressure difference, and the sludge discharge peristaltic pump is turned on at the same time to maintain the sludge concentration in the membrane tank; 3) During this period, samples are taken along the height for water quality detection, such as turbidity, ammonia nitrogen, CODcr, etc.; 4) After the experiment is completed, drain the raw water in the membrane tank, and record the phenomenon of sludge accumulation on the upper-layer membrane filaments and the phenomenon of broken filaments of the lower-layer membrane filaments.

[0052] For the test results, please refer to the appendix of the specification Figures 4 - 5 and 8 - 10. Comparative Example 2

[0053] A method for purifying water using an MBR double-layer component membrane tank. The MBR double-layer component membrane tank only has aeration by the pulse aeration box (5) at the bottom. Within the range of sludge concentration of 6000 - 8000 mg / L, it is controlled by one aeration pump, and the aeration intensity of the bottom pulse aeration box is 0.12 m 3 / m 2 •h.

[0054] A periodic experiment on the raw water in the inlet channel of the membrane tank was carried out for 30 days.

[0055] The method includes the following steps: 1) Draw the raw water in the inlet channel of the membrane tank into the raw water bucket, and use the inlet peristaltic pump to add it into the MBR double-layer component membrane tank (3); 2) Use the effluent gear pump for suction. The pressure sensor and the transmembrane pressure difference display detect the change of the transmembrane pressure difference, and the sludge discharge peristaltic pump is turned on at the same time to maintain the sludge concentration in the membrane tank; 3) During this period, samples are taken along the height for water quality detection, such as turbidity, ammonia nitrogen, CODcr, etc., and a temperature, pressure and flow detector is used to detect the wind pressure and air volume parameters at the outlet of the aeration pump and the air inlet of the aeration component, and calculate the power consumption; 4) Perform maintenance cleaning every 3 days with a sodium hypochlorite solution concentration of 200 - 300 ppm, that is, use the effluent gear pump to reverse the solution into the inside of the membrane filaments for backwashing; 5) The maintenance cleaning plan in step 4) is as follows: In the first stage, use a sodium hypochlorite solution with a concentration of 200 - 300 ppm to reverse into the inside of the membrane filaments, the chemical addition time is 300 s, stand still for 240 s, and the aeration time is 180 s. In the second stage, use a sodium hypochlorite solution with a concentration of 200 - 300 ppm to reverse into the inside of the membrane filaments, the chemical addition time is 30 s, stand still for 240 s, and the aeration time is 30 s, repeat 8 times; 4) After the experiment is completed, drain the raw water in the membrane tank, and record the phenomenon of sludge accumulation on the upper-layer membrane filaments and the phenomenon of broken filaments of the lower-layer membrane filaments.

[0056] For the specific results, please refer to the appendix of the specification Figure 6 and7 .

[0057] Referring to Example 1 and 3 and Comparative Examples 1-2, when the aeration intensity of the double-layer aeration of the first MBR membrane module + the second MBR membrane module described in Example 1 is 0.04 (upper) + 0.08 (lower) m 3 / m 2 •h, the transmembrane pressure difference of the first MBR membrane module + the second MBR membrane module within 72 hours is lower than that of the single port at the lower layer, indicating that a lower aeration intensity and the distribution method of 0.04 (upper) + 0.08 (lower) m 3 / m 2 •h can more effectively prevent the increase of the pressure difference of the membrane module.

[0058] When the aeration intensity of the double-layer aeration of the first MBR membrane module (upper part) + the second MBR membrane module (lower layer) described in Example 1 is 0.04 (upper) + 0.08 (lower) m 3 / m 2 •h, as the time increases beyond 5 days, both the first MBR membrane module + the second MBR membrane module with double-port air intake show a lower transmembrane pressure difference, proving that the use of double-layer aeration and the distribution method of 0.04 (upper) + 0.08 (lower) m 3 / m 2 •h can delay the increase of the pressure difference of the membrane module, extend the time for replacing the membrane module, and increase the service life of the membrane module.

[0059] By comparing Example 3 and Comparative Example 2, it can be known that as time goes by, the transmembrane pressure difference of the membrane module with single-port aeration increases significantly, especially the transmembrane pressure difference of the upper membrane filaments increases greatly. Using single-port aeration can only keep the pressure difference of the lower membrane filaments at the same level as that of double-layer aeration.

[0060] Moreover, in the previous research, the double-port aeration mode (aeration intensity of 0.06 (upper) + 0.06 (lower) m 3 / (m 2 •h)) is the optimal power consumption solution. Comparing with the aeration power consumption of the single-port aeration mode (aeration intensity of 0.12 m 3 / (m 2 •h)), the power consumption of double-port (layer) aeration is smaller than that of single-port (layer) aeration.

[0061] In the double-port aeration mode, the power of the middle perforated pipe is about half of the power of the bottom pulse aeration box.

[0062] At the same time, the transmembrane pressure difference growth of the upper and lower membrane filaments in double-port (layer) aeration is slower than that in single-port (layer) aeration.

[0063] The "0.06 + 0.06" type double-orifice aeration can effectively alleviate the phenomenon of rapid increase in the transmembrane pressure difference in the upper layer. When the transmembrane pressure difference reaches 20 kPa, restorative cleaning is carried out, which lasts for 21 days and 33 days respectively, with an expected single-time extension of 12 days and a reduction of 6 times of restorative cleaning per year. Taking a certain water purification plant as an example, it is expected to save 1.4112 million yuan of drug consumption for restorative cleaning per year.

[0064] At the same time, verified by actual instruments, the "0.06 + 0.06" type double-orifice aeration actually saves 25% energy compared with single-orifice aeration. Taking the annual power consumption of the membrane pool blower in a certain water purification plant as 5,366,650 kWh as an example, it can save 1,341,660 kWh of electricity per year, about 912,300 yuan per year.

[0065] Thus, the operation cost in the production process of the water purification plant is reduced, and the purpose of carbon reduction is achieved.

[0066] The above has described in detail the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principle and spirit of the present invention, various changes, modifications, substitutions and variations made to these embodiments still fall within the protection scope of the present invention.

Claims

1. A double-layer aeration system to prevent wire breakage and mud accumulation in a double-layer MBR membrane pool, comprising a raw water pool, a raw water inlet peristaltic pump, a double-layer MBR membrane pool, a first aeration structure, a second aeration structure, an aeration pump, a gas meter, a water outlet gear pump, an ultrafiltration membrane module, a pressure sensor, a transmembrane pressure difference display, a mud discharge peristaltic pump, and a water outlet pool, characterized in that: The MBR double-layer component membrane pool includes a first MBR membrane component and a second MBR membrane component, which are arranged vertically in the MBR double-layer component membrane pool, and the first MBR membrane component and the second MBR membrane component are arranged in parallel, the first aeration structure is located between the first MBR membrane component and the second membrane component, and the second aeration structure is located at the lower part of the second membrane component, and the aeration intensity ratio of the first aeration structure to the second aeration structure is 0.5-1.

2. A double-layer aeration system for preventing membrane wire breakage and mud accumulation in a double-layer MBR module pool according to claim 1, characterized in that: The MBR double-layer membrane pools are provided in multiple parallel configurations, the number of the MBR double-layer membrane pools is at least 2, and the first aeration structure and the second aeration structure are perforated aeration tubes or pulse aeration boxes.

3. A double-layer aeration system for preventing broken wires and mud accumulation in a double-layer MBR module pool according to claim 1, characterized in that: The raw water pool is connected to the raw water inlet peristaltic pump and the MBR double-layer component membrane pool through a pipeline, and the ultrafiltration membrane component is arranged in the MBR double-layer component membrane pool.

4. A double-layer aeration system for preventing membrane wire breakage and mud accumulation in a double-layer MBR module pool according to claim 1, characterized in that: The water outlet pool is connected to the ultrafiltration membrane assembly through a water outlet gear pump and a pressure sensor.

5. A double-layer aeration system for preventing broken wires and mud accumulation in a double-layer MBR module membrane pool according to claim 4, characterized in that: The first MBR membrane assembly and the second MBR membrane assembly are both provided with pressure sensors in the MBR double-layer assembly membrane pool. The first MBR membrane assembly is located in the vertical direction of the second MBR membrane assembly. The lower parts of the first MBR membrane assembly and the second MBR membrane assembly are provided with perforated aeration pipes and / or pulse aeration boxes.

6. A double-layer aeration system for preventing membrane wire breakage and mud accumulation in a double-layer MBR module pool according to claim 4 or 5, characterized in that: The pressure sensor is installed at the pipeline outlet of the ultrafiltration membrane assembly and connected to the transmembrane pressure difference display.

7. A double-layer aeration system for preventing membrane breakage and mud accumulation in a double-layer MBR module pool according to claim 1, characterized in that: The end of the perforated aeration tube has at least one bent portion.

8. A double-layer aeration system for preventing membrane wire breakage and mud accumulation in a double-layer MBR module pool according to claim 1, characterized in that: The ultrafiltration membrane assembly comprises a plurality of hollow fiber membranes connected in parallel and a water outlet connected to the hollow fiber membranes. The ultrafiltration membrane assembly is arranged inside the MBR double-layer assembly membrane pool.

9. A double-layer aeration system for preventing membrane wire breakage and mud accumulation in a double-layer MBR module pool according to claim 1, characterized in that: The aeration pump is connected to the perforated aeration pipe and / or the pulse aeration box through a gas meter to achieve double-layer aeration.

10. A double-layer aeration system for preventing membrane wire breakage and mud accumulation in a double-layer MBR module pool according to claim 5, characterized in that: The aeration intensity of the first aeration structure and the second aeration structure is 0.04-0.08 m 3 / m 2 •h.

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