Low-energy-consumption AOA-MBR sewage treatment system

Abstract

The utility model belongs to the technical field of sewage treatment, and discloses a low-energy-consumption AOA-MBR sewage treatment system which comprises an AOA reaction tank, an MBR membrane tank, a first reflux unit and a second reflux unit, the AOA reaction tank is communicated with the MBR membrane tank; the first reflux unit is used for refluxing a mud-water mixture at the tail end of the anoxic environment in the AOA reaction tank to the front end of the anaerobic environment and / or the anoxic environment; and the second reflux unit is used for refluxing the mud-water mixture in the MBR membrane tank to the aerobic environment of the AOA reaction tank. According to the application, under the condition of ensuring that nitrate in the reflux liquid is extremely low as much as possible, an oxygen elimination link is omitted, and the nitrogen and phosphorus removal effect is ensured; moreover, dissolved oxygen in the MBR membrane tank is fully utilized to supply oxygen to the aerobic environment, so that the external oxygen supply amount is reduced, and the oxygen supply energy consumption is reduced. The arrangement is very beneficial to maintaining and guaranteeing the anoxic environment, the anaerobic environment and the aerobic environment in the AOA reaction tank, the nitrogen and phosphorus removal effect is guaranteed, and the energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to sewage treatment technical field, concretely is a kind of low-energy AOA-MBR sewage treatment system. BACKGROUND

[0002] AOA process is the abbreviation of anaerobic (A)-oxygen (O)-anoxic (A) process, omits internal reflux, adopts sludge double reflux mode, it converts the COD of influent into intracellular carbon source in anaerobic section, and these intracellular carbon sources are sealed in the body of microorganism. After passing through the oxygen zone, the intracellular carbon sources are used for denitrification in the anoxic zone, which can simultaneously remove nitrogen and phosphorus, and reduce the consumption of external carbon source.

[0003] MBR process, i.e. membrane bioreactor, is a sewage treatment technology combining membrane separation technology with biological treatment. It realizes the degradation of organic matter and solid-liquid separation in the same equipment by combining membrane element with biological reactor.

[0004] CN116177744A discloses a modified AOA process coupled with MBR for efficient nitrogen and phosphorus removal. The modified AOA process coupled with MBR for efficient nitrogen and phosphorus removal includes a water inlet pipe, a water outlet pipe, an oxygen depletion zone, an anaerobic zone, an aerobic zone, an anoxic zone, a membrane separation zone, and a sludge reflux assembly. The water inlet pipe is in communication with the anaerobic zone and the anoxic zone, and the water outlet pipe is in communication with the membrane separation zone. The first sludge reflux pipe has two ends in communication with the membrane separation zone and the oxygen depletion zone, and the second sludge reflux pipe has two ends in communication with the membrane separation zone and the anoxic zone.

[0005] The above technical solution is based on the modified AOA process coupled with MBR membrane separation for efficient nitrogen and phosphorus removal to solve the problems of low nitrogen removal efficiency and large carbon source dosage of existing MBR process, and has the advantages of high carbon source utilization rate, excellent nitrogen removal effect and low energy consumption. However, the above technical solution only utilizes the sludge separated in the membrane separation zone, and does not utilize the mud-water mixture rich in dissolved oxygen in the membrane separation zone, which can well supply oxygen to the previous process. UTILITY MODEL CONTENT

[0006] The present application aims at solving the above problems, and provides a low-energy AOA-MBR sewage treatment system. The sewage treatment system adopts a first reflux unit to reflux the sludge-water mixture at the end of the anoxic environment in the AOA reaction tank to the anaerobic environment and / or the front end of the anoxic environment, saves the oxygen consumption link while ensuring that the nitrate in the reflux liquid is as low as possible, and guarantees the denitrification and phosphorus removal effect. Meanwhile, the second reflux unit is adopted to reflux the sludge-water mixture in the MBR membrane tank to the aerobic environment of the AOA reaction tank, fully utilizes the dissolved oxygen in the MBR membrane tank, supplies oxygen for the aerobic environment, reduces the external oxygen supply amount, and saves the oxygen supply energy consumption. This setting is very beneficial to maintaining and guaranteeing the anoxic environment, anaerobic environment and aerobic environment in the AOA reaction tank, guarantees the denitrification and phosphorus removal effect, and reduces the energy consumption.

[0007] To achieve the above object, the present application provides the following technical scheme:

[0008] A low-energy AOA-MBR sewage treatment system, comprising an AOA reaction tank, an MBR membrane tank, a first reflux unit and a second reflux unit; the AOA reaction tank and the MBR membrane tank are communicated;

[0009] The first reflux unit is used to reflux the sludge-water mixture at the end of the anoxic environment in the AOA reaction tank to the anaerobic environment and / or the front end of the anoxic environment;

[0010] The second reflux unit is used to reflux the sludge-water mixture in the MBR membrane tank to the aerobic environment of the AOA reaction tank.

[0011] Preferably, the AOA reaction tank comprises an anaerobic zone, an aerobic zone and an anoxic zone communicated in sequence, the anoxic zone is communicated with the MBR membrane tank, and the first reflux unit is used to reflux the sludge-water mixture at the end of the anoxic zone to the anaerobic zone and / or the front end of the anoxic zone;

[0012] The second reflux unit is used to reflux the sludge-water mixture in the MBR membrane tank to the aerobic zone.

[0013] Preferably, it further comprises a first switching zone between the anaerobic zone and the aerobic zone, a second switching zone between the aerobic zone and the anoxic zone, and a reflux module; the first switching zone can be switched between the anaerobic state and the aerobic state; the second switching zone can be switched between the aerobic state and the anoxic state;

[0014] The reflux module is used to reflux the sludge-water mixture in the anoxic zone to the second switching zone in the anoxic state;

[0015] The second reflux unit is used to reflux the sludge-water mixture in the MBR membrane tank to the aerobic zone and / or the first switching zone in the aerobic state.

[0016] Preferably, the anoxic zones are two or more, and the sludge-water mixture output by the second switching zone sequentially passes through the anoxic zones and enters the MBR membrane tank, and the reflux module is used to reflux the sludge-water mixture in the rear anoxic zone to the front anoxic zone and / or the second switching zone in the anoxic state; the first reflux unit is used to reflux the sludge-water mixture in the rear anoxic zone to the anaerobic zone.

[0017] Preferably, the anaerobic zone is provided with a first stirring device; the first switching zone is provided with a second stirring device and a first aeration device for switching between anaerobic and aerobic conditions; the aerobic zone is provided with a second aeration device and a third stirring device; the second switching zone is provided with a fourth stirring device and a third aeration device for switching between aerobic and anoxic conditions; and the anoxic zone is provided with a fifth stirring device.

[0018] Preferably, the system further comprises a sedimentation tank between the AOA reaction tank and the MBR membrane tank, and a third reflux unit, the first reflux unit being used to reflux the sludge-water mixture in the sedimentation tank to the anaerobic environment, and the third reflux unit being used to reflux the sludge-water mixture in the sedimentation tank to the anoxic environment.

[0019] Preferably, the sedimentation tank is provided with a guide hopper at the bottom and an inclined plate assembly above the guide hopper, the inlet end of the sedimentation tank being located between the guide hopper and the inclined plate assembly, and the outlet end being located above the inclined plate assembly.

[0020] Preferably, the MBR membrane tank is provided with an aeration membrane assembly, a water outlet pipe connected to the aeration membrane assembly, and a water outlet pump arranged on the water outlet pipe.

[0021] Preferably, the system further comprises baffles arranged symmetrically and arranged in the MBR membrane tank, the aeration membrane assembly being located between the symmetrically arranged baffles and forming a sludge rising area between the symmetrically arranged baffles, and gaps being provided between the baffles and the inner wall of the tank body, the gaps being sludge settling areas.

[0022] Compared with the prior art, the application has the following advantages:

[0023] The first reflux unit is used to reflux the sludge-water mixture at the end of the anoxic environment in the AOA reaction tank to the anaerobic environment, thereby saving the oxygen consumption link while minimizing the nitrate and nitrate in the reflux liquid; and the second reflux unit is used to reflux the sludge-water mixture in the MBR membrane tank to the aerobic environment of the AOA reaction tank, thereby fully utilizing the dissolved oxygen in the MBR membrane tank to supply oxygen to the aerobic environment and reducing the amount of external oxygen supply, thereby saving the oxygen supply energy consumption. This arrangement is very beneficial for maintaining and protecting the anoxic environment, the anaerobic environment and the aerobic environment in the AOA reaction tank, ensuring the effect of denitrification and phosphorus removal, and reducing energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1is a structural schematic diagram of the AOA reaction tank and the MBR membrane tank of Example 1;

[0025] Figure 2 is a piping diagram of the low-energy AOA-MBR sewage treatment system of Example 1;

[0026] Figure 3 is a structural schematic diagram of the AOA reaction tank, the MBR membrane tank, and the sedimentation tank of Example 2;

[0027] Figure 4 is a piping diagram of the low-energy AOA-MBR sewage treatment system of Example 2;

[0028] In the drawings, the reference numbers are as follows:

[0029] AOA reaction tank 1; MBR membrane tank 2; first reflux unit 3; second reflux unit 4; reflux module 5; sedimentation tank 6; anaerobic zone 11; first switching zone 12; aerobic zone 13; second switching zone 14; anoxic zone 15; aerated membrane assembly 21; effluent pipe 22; effluent pump 23; baffle 24; first reflux pipe 31; first reflux pump 32; first reflux valve 33; second reflux pipe 41; second reflux pump 42; second reflux valve 43; third reflux pipe 51; third reflux pump 52; third reflux valve 53; inclined plate assembly 61; guide hopper 62; first stirring device 111; second stirring device 121; first aeration device 122; third stirring device 131; second aeration device 132; fourth stirring device 141; third aeration device 142; fifth stirring device 151; first sub-pipe 411; first control valve 412; second sub-pipe 511; second control valve 512. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0031] Example 1

[0032] Reference Figures 1-2 A low-energy AOA-MBR sewage treatment system, comprising an AOA reaction tank 1, an MBR membrane tank 2, a first reflux unit 3, and a second reflux unit 4; the AOA reaction tank 1 and the MBR membrane tank 2 are in communication;

[0033] The first reflux unit 3 is used to reflux the sludge-water mixture at the end of the anoxic environment in the AOA reaction tank 1 to the front end of the anaerobic environment and / or the anoxic environment.

[0034] The second reflux unit 4 is used to reflux the sludge-water mixture in the MBR membrane tank 2 to the aerobic environment of the AOA reaction tank 1.

[0035] Under this design, because the last stage of the AOA reaction tank 1 is an anoxic environment, the anoxic environment has converted most of the nitrate into nitrogen, so the dissolved oxygen and nitrate in the sludge-water mixture are also relatively low, and it is very beneficial to maintain and protect the anoxic environment and the anaerobic environment of the system to reflux them to the anaerobic zone 11 through the first reflux unit 3, which helps the denitrification and phosphorus removal effect.

[0036] In the MBR membrane tank 2, the dissolved oxygen in the sludge-water mixture will gradually increase under the continuous aeration, and the purpose of the second reflux unit 4 is to use the dissolved oxygen brought out by the sludge-water mixture from the MBR membrane tank 2 to supply oxygen for the aerobic environment of the AOA reaction tank 1, fully utilize the dissolved oxygen in the MBR membrane tank 2 to supply oxygen for the aerobic environment, reduce the external oxygen supply amount, and save the oxygen supply energy consumption. This setting is very beneficial to maintain and protect the anoxic environment, the anaerobic environment, and the aerobic environment in the AOA reaction tank 1, guarantees the denitrification and phosphorus removal effect, and reduces the energy consumption.

[0037] In this embodiment, the AOA reaction tank 1 comprises an anaerobic zone 11, a first switching zone 12, an aerobic zone 13, a second switching zone 14, and an anoxic zone 15 which are sequentially communicated; the anoxic zone 15 is communicated with the MBR membrane tank 2;

[0038] Further, the anaerobic zone 11 is provided with a first stirring device 111; the first switching zone 12 is provided with a second stirring device 121 and a first aeration device 122 for switching between anaerobic and aerobic; the aerobic zone 13 is provided with a second aeration device 132 and a third stirring device 131; the second switching zone 14 is provided with a fourth stirring device 141 and a third aeration device 142 for switching between aerobic and anoxic; and the anoxic zone 15 is provided with a fifth stirring device 151.

[0039] The principle and working mode of the AOA reaction tank 1 can refer to the technical solution disclosed in Chinese patent CN112875859A.

[0040] Briefly speaking, in the first switch zone 12, when the first aeration device 122 is closed and the second stirring device 121 is opened, the first switch zone 12 is in an anaerobic state, the anaerobic zone 11 of the AOA reaction tank 1 is increased, the anaerobic residence time is prolonged, the phosphorus removal effect is increased, and the energy consumption is reduced. At this time, the second reflux module 4 refluxes the sludge-water mixture in the MBR membrane tank 2 to the aerobic zone 13, but not to the first switch zone 12; when the sludge-water mixture in the MBR membrane tank 2 is refluxed to the first switch zone 12, the first switch zone 12 is in an aerobic state, the aerobic zone 13 of the AOA reaction tank 1 is increased, the aerobic residence time is prolonged, the nitrification is increased, and the denitrification effect is increased. At this time, because of the supplement of dissolved oxygen in the MBR membrane tank 2, the aeration amount of the first aeration device 122 is small or not working, so it is difficult to push the sludge, so the cooperation of the second stirring device 121 is needed to push the sludge, therefore the first aeration device 122 and the second stirring device 121 are opened according to the mixing state of the sludge in the first switch zone 12.

[0041] Further, in the aerobic zone 13, not only the second aeration device 132 is arranged, but also the third stirring device 131 is arranged. Because of the reflux of the sludge-water mixture in the MBR membrane tank 2, in the embodiment, the aeration amount of the second aeration device 132 is relatively small, when the dissolved oxygen in the aerobic zone 13 can meet the oxygen supply requirement of the system, and can maintain the sludge-water mixture uniformly suspended, the third stirring device 131 is closed; when the dissolved oxygen in the aerobic zone 13 can meet the oxygen supply requirement of the system, but is insufficient to maintain the sludge-water mixture uniformly suspended, the third stirring device 131 is opened, to ensure that the sludge in the aerobic zone 13 is uniformly mixed. That is to say, the third stirring device 131 in the aerobic zone 13 only has the effect of ensuring that the sludge in the aerobic zone 13 is uniformly mixed, and is opened according to the mixing state, and is not necessary to be always opened.

[0042] Moreover, the refluxed sludge-water mixture can basically meet the oxygen supply requirement of the aerobic zone 13, at this time, the second aeration device 132 in the aerobic zone 13 can not be opened, when the dissolved oxygen of the refluxed sludge-water mixture is insufficient to meet the oxygen supply requirement of the aerobic zone 13, at this time, the second aeration device 132 in the aerobic zone 13 is opened, to supply a small amount of oxygen. That is to say, the oxygen supply amount of the aerobic zone 13 basically comes from the dissolved oxygen of the refluxed sludge-water mixture, and the second aeration device 132 in the aerobic zone 13 is only an auxiliary and supplementary aeration device.

[0043] In the embodiment, the anoxic zone 15 is two, and the sludge-water mixture output from the second switch zone 14 enters the MBR membrane tank 2 after passing through the two anoxic zones 15 in turn, the reflux module 5 is used to reflux the sludge-water mixture in the rear anoxic zone 15 to the front anoxic zone 15 and / or the second switch zone 14 in an anoxic state; the first reflux unit 3 is used to reflux the sludge-water mixture in the rear anoxic zone 15 to the anaerobic zone 11.

[0044] Further, in the second switching zone 14, when the third aeration device 142 is opened and the fourth stirring device 141 is closed, at this time, the second switching zone 14 is in an aerobic state, the aerobic zone 13 of the AOA reaction tank 1 is increased, the aerobic residence time is prolonged, the nitrification is enhanced, the ammonia nitrogen is further converted into nitrate, the sludge-water mixture is refluxed from the rear anoxic zone 15 to the front anoxic zone 15 by the reflux module 5, and is not refluxed to the second switching zone 14; when the third aeration device 142 is closed and the fourth stirring device 141 is opened, the sludge-water mixture is refluxed to the second switching zone 14 by the reflux module 5, of course, the second switching zone 14 is in an anoxic state, the anoxic zone 15 of the AOA reaction tank 1 is increased, the anoxic residence time is prolonged, the denitrification effect is increased, and the energy consumption is reduced, and the sludge-water mixture can also be refluxed to the second switching zone 14 and the front anoxic zone 15 by the reflux module 5.

[0045] Specifically, the specific operation state of the first switching zone 12 and the second switching zone 14 can be adjusted by the operator according to the actual data model and online operation data according to the changes of water quality, water temperature, seasons, day and night, water volume and different treatment requirements.

[0046] In the embodiment, the first reflux unit 3 includes a first reflux pipe 31, a first reflux pump 32 arranged on the first reflux pipe 31, and a first reflux valve 33 arranged on the first reflux pipe 31, and the first reflux pipe 31 is used for refluxing the sludge-water mixture in the rear anoxic zone 15 to the anaerobic zone 11.

[0047] The second reflux unit 4 includes a second reflux pipe 41, a second reflux pump 42 arranged on the second reflux pipe 41, a second reflux valve 43 arranged on the second reflux pipe 41, two first branch pipes 411 connected at the end of the second reflux pipe 41, and a first control valve 412 arranged on each of the two first branch pipes 411. In the preferred embodiment, the two first branch pipes 411 are respectively connected to the inlet end of the first switching zone 12 and the inlet end of the aerobic zone 13.

[0048] The reflux module 5 includes a third reflux pipe 51, a third reflux pump 52 arranged on the third reflux pipe 51, a third reflux valve 53 arranged on the third reflux pipe 51, two second branch pipes 511 connected at the end of the third reflux pipe 51, and a second control valve 512 arranged on each of the two second branch pipes 511. In the preferred embodiment, the two second branch pipes 511 are respectively connected to the inlet end of the second switching zone 14 and the inlet end of the front anoxic zone 15.

[0049] Preferably, the MBR membrane tank 2 is provided with an aeration membrane assembly 21, a water outlet pipe 22 connected to the aeration membrane assembly 21, and a water outlet pump 23 arranged on the water outlet pipe 22.

[0050] Specifically, the aeration membrane assembly 21 is an MBR membrane assembly with an aeration pipe built-in, and the specific structure can refer to the MBR membrane assembly and the aeration main pipe disclosed in Chinese patent CN215627055U, so the specific structure and working principle of the aeration membrane assembly 21 will not be described in detail in this embodiment. The aeration membrane assembly 21 of this embodiment can adopt the mode of ultrafiltration membrane plus aeration main pipe.

[0051] Preferably, a baffle 24 is further included, the baffle 24 is symmetrically arranged and disposed in the MBR membrane tank 2, the aeration membrane assembly 21 is located between the symmetrically arranged baffles 24 and forms a sludge rising area between the symmetrically arranged baffles 24, and a gap is provided between the baffle 24 and the inner wall of the tank body, which is a sludge settling area.

[0052] Under this design, part of the sludge of the sludge-water mixture entering the MBR membrane tank 2 will directly settle at the bottom, and the other part will enter the sludge rising area under the action of the airflow of the aeration membrane assembly 21. In the sludge rising area, the sludge is continuously disturbed by the bubbles, making it suspended in the water, and under the push of the airflow of the aeration membrane assembly 21, it passes over the baffle 24 from the top of the baffle 24 into the sludge settling area. The sludge in the sludge settling area will not be affected by the bubbles, so the sludge settling area can accelerate the sedimentation of the sludge. At the bottom of the baffle 24, the airflow of the aeration membrane assembly 21 will form a low-pressure area at the bottom of the baffle 24, prompting the water flow and a small part of the sludge at the bottom of the sludge settling area to enter the sludge rising area, thereby forming a circulation around the baffle 24, promoting the sedimentation of the sludge, reducing the burden of the aeration membrane assembly 21, and finally the sludge-water mixture settled at the bottom will be returned to the first switching area 12 and / or the aerobic area 13 in the aerobic state under the action of the second reflux unit 4.

[0053] Because the aeration amount of the MBR membrane tank 2 is large, the dissolved oxygen in the reflux liquid of the MBR membrane tank 2 is basically in a saturated state, and the reflux ratio of the MBR membrane tank 2 is large. The proportion of the reflux in the conventional MBR process aerobic tank is 200% to 400%, and the dissolved oxygen in the mixed liquid provides a large amount of dissolved oxygen for the aerobic tank, greatly reducing the oxygen supply amount of the second aeration device 132 of the aerobic area 13.

[0054] Further, the overwater holes of the anaerobic area 11, the aerobic area 13, and the aerobic area 13 and the anoxic area 15 are provided with anti-backflow devices such as water weirs, short pipes extending into the tank, flap valves, or other anti-backflow devices to ensure that the mixed liquid of the aerobic area 13 will not be mixed and flowed to the anaerobic area 11 or the anoxic area 15, so that each area maintains a good biochemical reaction environment.

[0055] Embodiment 2

[0056] Reference Figures 3-4The embodiment 2 further comprises a sedimentation tank 6 and a third reflux unit between the AOA reaction tank 1 and the MBR membrane tank 2 of the embodiment 1, the first reflux unit 3 is used to reflux the sludge-water mixture in the sedimentation tank 6 to the anaerobic environment, and the third reflux unit is used to reflux the sludge-water mixture in the sedimentation tank 6 to the anoxic environment.

[0057] Specifically, the first reflux unit 3 is used to reflux the sludge-water mixture in the sedimentation tank 6 to the anaerobic zone 11, and the third reflux unit is used to reflux the sludge-water mixture in the sedimentation tank 6 to the second switching zone 14 in the anoxic state and / or the anoxic zone 15.

[0058] The third reflux unit is only different from the reflux module 5 in the embodiment 1 in that the input end is connected to the sedimentation tank 6 instead of the anoxic zone 15 behind the reflux module 5. It can be understood that, after the sedimentation tank 6 is added, the connection position of the input end of the reflux module 5 is changed from the anoxic zone 15 to the sedimentation tank 6.

[0059] In the embodiment, the sedimentation tank 6 is provided with a guide funnel 62 at the bottom and a tilting plate assembly 61 above the guide funnel 62, the inlet end of the sedimentation tank 6 is located between the guide funnel 62 and the tilting plate assembly 61, and the outlet end is located above the tilting plate assembly 61.

[0060] Specifically, under the guidance of the guide funnel 62, the sludge entering the sedimentation tank 6 is more concentrated and gathered at the bottom of the sedimentation tank 6, so as to improve the concentration of the sludge refluxed to the anaerobic zone 11, the second switching zone 14 in the anoxic state and the anoxic zone 15, and the tilting plate assembly 61 can adopt the structure of a tilting plate or a tilting pipe to improve the sedimentation effect and avoid the sludge in the guide funnel 62 from flowing back to the upper layer.

[0061] The sludge of the sedimentation tank 6 comes from the sludge precipitated in the anoxic zone 15, and the anoxic zone 15 has converted most of the nitrate into nitrogen, so the dissolved oxygen and nitrate in the sludge-water mixture are also relatively low, which is beneficial to maintaining and ensuring the anoxic environment and the anaerobic environment, and helps the effect of denitrification and phosphorus removal. In addition, after the sludge is pre-deposited, the sludge directed to the funnel 62 is concentrated, and the concentration is relatively high, which can reduce the amount of backflow to the AOA reaction tank 1, and also can reduce energy consumption. By setting the sedimentation tank 6, the sludge concentration of the MBR membrane tank 2 will be low, and the membrane pollution rate will be reduced, which can greatly reduce the air required for the ultrafiltration membrane to shake, and thus greatly reduce the energy required for shaking. Because the sludge concentration of the MBR membrane tank 2 is low, the degree of membrane pollution will be greatly reduced, and the resistance of clean water through the membrane will also be greatly reduced. Not only can a larger water flux be achieved with a smaller membrane area, but the investment cost will also be reduced. The pumping energy consumption of the effluent will also be greatly reduced, saving the operation cost of the effluent. In addition, the frequency of membrane cleaning will be reduced, and the operation cost of membrane cleaning will also be greatly reduced.

[0062] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A low-energy AOA-MBR wastewater treatment system, characterized in that, It includes an AOA reactor, an MBR membrane tank, a first reflux unit, and a second reflux unit; the AOA reactor and the MBR membrane tank are connected. The first reflux unit is used to reflux the mud-water mixture at the end of the anoxic environment in the AOA reactor to the front of the anaerobic environment and / or the anoxic environment. The second reflux unit is used to reflux the sludge-water mixture in the MBR membrane tank back to the aerobic environment of the AOA reactor.

2. The low-energy AOA-MBR wastewater treatment system according to claim 1, characterized in that, The AOA reactor includes an anaerobic zone, an aerobic zone, and an anoxic zone connected in sequence. The anoxic zone is connected to the MBR membrane tank. The first reflux unit is used to reflux the mud-water mixture at the end of the anoxic zone to the anaerobic zone and / or the front end of the anoxic zone. The second reflux unit is used to reflux the sludge-water mixture in the MBR membrane tank back to the aerobic zone.

3. The low-energy AOA-MBR wastewater treatment system according to claim 2, characterized in that, It also includes a first switching zone located between the anaerobic zone and the aerobic zone, a second switching zone located between the aerobic zone and the anoxic zone, and a reflux module; the first switching zone can switch between anaerobic and aerobic states; the second switching zone can switch between aerobic and anoxic states; The reflux module is used to reflux the mud-water mixture in the anoxic zone to the second switching zone in anoxic condition. The second reflux unit is used to reflux the sludge-water mixture in the MBR membrane tank to the aerobic zone and / or the first switching zone of the aerobic state.

4. The low-energy AOA-MBR wastewater treatment system according to claim 3, characterized in that, There are two or more anoxic zones, and the mud-water mixture output from the second switching zone enters the MBR membrane tank after passing through the anoxic zones in sequence. The reflux module is used to reflux the mud-water mixture in the anoxic zone located at the rear to the anoxic zone located at the front and / or the second switching zone in anoxic state; the first reflux unit is used to reflux the mud-water mixture in the anoxic zone located at the rear to the anaerobic zone.

5. The low-energy AOA-MBR wastewater treatment system according to claim 4, characterized in that, The anaerobic zone is equipped with a first stirring device; the first switching zone is equipped with a second stirring device and a first aeration device for switching between anaerobic and aerobic conditions; the aerobic zone is equipped with a second aeration device and a third stirring device; the second switching zone is equipped with a fourth stirring device and a third aeration device for switching between aerobic and anoxic conditions; and the anoxic zone is equipped with a fifth stirring device.

6. The low-energy AOA-MBR wastewater treatment system according to claim 1, characterized in that, It also includes a sedimentation tank located between the AOA reactor and the MBR membrane tank, and a third reflux unit. The first reflux unit is used to reflux the sludge-water mixture in the sedimentation tank to the anaerobic environment; the third reflux unit is used to reflux the sludge-water mixture in the sedimentation tank to the anoxic environment.

7. The low-energy AOA-MBR wastewater treatment system according to claim 6, characterized in that, The sedimentation tank is equipped with a guide funnel at the bottom and an inclined plate assembly above the guide funnel. The inlet end of the sedimentation tank is located between the guide funnel and the inclined plate assembly, and the outlet end is located above the inclined plate assembly.

8. The low-energy AOA-MBR wastewater treatment system according to claim 1, characterized in that, The MBR membrane tank is equipped with an aeration membrane module, an outlet pipe connected to the aeration membrane module, and an outlet pump installed on the outlet pipe.

9. The low-energy AOA-MBR wastewater treatment system according to claim 8, characterized in that, It also includes baffles, which are symmetrically arranged and installed in the MBR membrane tank. The aeration membrane assembly is located between the symmetrically arranged baffles and forms a sludge rising area between the symmetrically arranged baffles. There is a gap between the baffles and the inner wall of the tank, which is a sludge settling area.

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