An MBR membrane bioreactor sewage treatment process

Abstract

The present invention discloses a sewage treatment process for an MBR membrane bioreactor, which includes that sewage successively enters an inlet area and a pre-anoxic area; then respectively enters an anoxic area and an anaerobic area, where denitrification reaction occurs in the anoxic area and phosphorus release reaction occurs in the anaerobic area; afterwards, the sewage converges and successively passes through a first low-oxygen aeration area and a second low-oxygen aeration area, and oxygen is supplemented through an aeration device in both the first low-oxygen aeration area and the second low-oxygen aeration area to carry out nitrification reaction; the sewage after nitrification reaction enters an air-water backwashing sedimentation area, and sedimentation occurs in the air-water backwashing sedimentation area for sludge-water separation; the supernatant of the air-water backwashing sedimentation area enters the MBR membrane area for enhanced treatment. The present invention couples the low-oxygen biological nitrogen and phosphorus removal process with the MBR membrane process into one. These two processes can either operate in series, each forming its own independent microbial metabolism system, or achieve interconnection and integration through a membrane air-lift reflux device to form a complete organic metabolism system.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly relates to an MBR membrane bioreactor sewage treatment process. Background Art

[0002] With the introduction of the national policy of carbon peaking and carbon neutrality, energy conservation, consumption reduction, low-carbon operation and resource utilization of sewage treatment are imperative. At present, for the MBR membrane bioreactor, biological phosphorus removal needs to be completed under the alternating anaerobic and aerobic environments at the front end of the membrane tank, while biological nitrogen removal needs to be carried out under the two conditions of anoxic and aerobic at the front end of the membrane tank. Therefore, to achieve the purpose of simultaneous phosphorus and nitrogen removal, it is necessary to create three physiological environments of aerobic, anoxic and anaerobic required by microorganisms, thus constituting the A / O (anaerobic-anoxic-oxic) process for both phosphorus and nitrogen removal. At present, this process has been applied in many sewage treatment plants around the world. However, the long-term operation results show that when the phosphorus removal effect is good, the nitrogen removal effect is often poor; when the nitrogen removal effect is good, the phosphorus removal effect is not ideal, and generally it is impossible to achieve good removal effects simultaneously, and the operation energy consumption, investment, etc. are all relatively high. Summary of the Invention

[0003] In view of the deficiencies in the above problems, the present invention provides an MBR membrane bioreactor sewage treatment process.

[0004] To achieve the above object, the present invention provides an MBR membrane bioreactor sewage treatment process, which includes that sewage first enters the inlet area, and the free oxygen in the sewage is eliminated under the metabolic action of microorganisms;

[0005] The air-lift devices in the anoxic area and the anaerobic area are started, and the sewage enters the pre-anoxic area from the inlet area, and part of the combined nitrogen is first degraded by the microorganisms and the free oxygen in the sewage is continuously decomposed, so as to create a strict anaerobic environment for the phosphorus-releasing bacteria in the subsequent anaerobic area and strengthen the biological phosphorus removal effect;

[0006] After that, it enters the anoxic area and the anaerobic area respectively, and a denitrification reaction is carried out under the action of denitrifying bacteria in the anoxic area, and a phosphorus release reaction is carried out under the action of phosphorus-releasing bacteria in the anaerobic area;

[0007] Then, the sewage flowing out from the anoxic area and the anaerobic area converges and sequentially passes through the first low-oxygen aeration area and the second low-oxygen aeration area, and oxygen is supplemented through the aeration device in both the first low-oxygen aeration area and the second low-oxygen aeration area, so that the nitrifying bacteria inside can carry out synchronous short-cut nitrification and denitrification under the control condition of low oxygen (DO not higher than 1 mg / l), thus realizing that a certain total nitrogen removal can also be achieved in the low-oxygen aeration area, and no longer completely relying on the anoxic area to remove all the total nitrogen, thereby achieving the effect of strengthening nitrogen removal and improving the total nitrogen removal rate;

[0008] The sewage after nitrification reaction enters the air-water backwashing sedimentation area, and sedimentation is carried out in the air-water backwashing sedimentation area for mud-water separation;

[0009] The supernatant of the air-water backwashing sedimentation area enters the MBR membrane area for enhanced treatment.

[0010] Preferably, an air-lift device is also provided in the MBR membrane area, and an air-water backwashing device and a sludge reflux device are provided in the air-water backwashing sedimentation area;

[0011] When the air-lift device in the MBR membrane area and the air-water backwashing device are started synchronously, the air-water backwashing device washes out the flocculent sludge with weak sedimentation performance in the air-water backwashing sedimentation area to the MBR membrane area, and the sludge reflux device refluxes the sludge at the bottom of the air-water backwashing sedimentation area with low SVI to the water inlet area;

[0012] After being treated in the MBR membrane area, the sewage inside is discharged to the second anoxic aeration area through the air-lift device provided therein.

[0013] Preferably, when the air-lift device in the MBR membrane area and the air-water backwashing device are closed synchronously, the supernatant of the air-water backwashing sedimentation area enters the MBR membrane area and is intensively treated under the action of special bacteria in the MBR membrane area, so as to make up for the influence on the metabolic rates of nitrification reaction and carbonization reaction under the limited anoxic condition (DO not higher than 1 mg / l) in the first anoxic area and the second anoxic area. The incomplete ammonia nitrogen and organic matters can be completely removed under the condition of high dissolved oxygen (DO not lower than 1 mg / l) in the MBR membrane area, ensuring that stable up-to-standard discharge can be achieved, and its clear water is discharged through the membrane of the MBR membrane area.

[0014] Preferably, the mud-water mixture in the second anoxic aeration area is refluxed to the water inlet area.

[0015] Preferably, an air-lift device is also provided in the first anoxic aeration area, and under the action of the gas device, the mud-water mixture in the second anoxic aeration area is refluxed to the first anoxic aeration area.

[0016] Preferably, the air-lift devices in the anoxic area and the anaerobic area are both arranged at the connection of the anoxic area, the anaerobic area and the first anoxic aeration area, and the air-lift devices in the anoxic area, the anaerobic area and the first anoxic aeration area all obtain the air power source through the aeration device in the first anoxic aeration area.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] First, in the present invention, the anaerobic zone and the anoxic zone are arranged side by side, which can extend the reaction time of microorganisms in their respective functional zones, enhancing the biological nitrogen and phosphorus removal capacity and efficiency. Second, the low-oxygen biochemical process and the MBR membrane treatment process are operated in series independently. This enables each biochemical process to independently screen, domesticate, and cultivate special bacterial communities with unique technical advantages for their respective characteristic pollutants, so that the membrane area can further remove the characteristic pollutants that cannot be removed by the low-oxygen biochemical treatment process and are affected by low oxygen and the metabolic rate is restricted. Therefore, it can achieve the maximized removal of specific characteristic pollutants to be removed by their respective treatment processes. Third, by simultaneously turning on the membrane air-lift device and the air washing and backwashing device in the air washing sedimentation area, the bacterial genera of the low-oxygen biochemical process and the membrane treatment process are integrated to achieve the unity of bacterial genera, so that the membrane area can extend the biological metabolic reaction time of the pollutants incompletely removed by the low-oxygen biochemical treatment process, thereby further enhancing the low-oxygen biochemical removal effect and capacity. The organic combination of the low-oxygen aeration biochemical reaction and the MBR membrane can not only achieve the simultaneous and efficient removal of ammonia nitrogen, total nitrogen, and organic matter, reduce the operating energy consumption, and reduce the carbon source dosage, but also through the design method of combining the low-oxygen biochemical process and the MBR membrane treatment process, that is, when the membrane air-lift device and the air-water backwashing device are not turned on, the low-oxygen biochemical process and the MBR membrane treatment process can operate independently, cultivating specific bacterial genera that can remove the characteristic pollutants to be removed by themselves; and through the combined action when the membrane air-lift device and the air-water backwashing device are turned on simultaneously, the low-oxygen biochemical process and the MBR membrane treatment process are integrated to achieve the unity of microbial metabolic bacterial genera, so that the membrane pool can extend the biological metabolic reaction time of the pollutants incompletely removed by the low-oxygen biochemical treatment process, thereby further enhancing the low-oxygen biochemical removal effect and capacity. Therefore, the present invention can fundamentally broaden the application scope of MBR and has high research value and practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is the sewage treatment process diagram of the MBR membrane bioreactor of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] The following will be further described in detail with reference to the Figure 1 drawings for the present invention:

[0022] Reference Figure 1

[0022] , the present invention provides a sewage treatment process for an MBR membrane bioreactor. The MBR membrane bioreactor includes an influent area, a pre-anoxic area, an anoxic area, an anaerobic area, a first low-oxygen aeration area, a second low-oxygen aeration area, an air-water backwashing sedimentation area, and an MBR membrane area. Air-lift devices are provided in the anoxic area, the anaerobic area, and the MBR membrane area, and aeration devices are provided in the first low-oxygen aeration area and the second low-oxygen aeration area; an air-water backwashing device is provided in the air-water backwashing sedimentation area;

[0023] The steps of its treatment process include:

[0024] Sewage first enters the influent area, and the oxygen in the sewage is eliminated under the metabolic action of microorganisms. Sewage first enters the influent area, and the relatively high-concentration influent first passes through the metabolic action of microorganisms, and the free oxygen in the sewage is exhausted here, providing the best metabolic operating conditions required for subsequent anaerobic and anoxic biological reactions;

[0025] Start the air-lift devices in the anoxic area and the anaerobic area. The sewage enters the pre-anoxic area from the influent area, and the oxygen in the sewage is further decomposed by microorganisms, and denitrification reaction is carried out;

[0026] After that, it enters the anoxic area and the anaerobic area respectively. Denitrification reaction is carried out under the action of denitrifying bacteria in the anoxic area, and phosphorus release reaction is carried out under the action of phosphorus-releasing bacteria in the anaerobic area;

[0027] Then, the sewage flowing out from the anoxic area and the anaerobic area converges and sequentially passes through the first low-oxygen aeration area and the second low-oxygen aeration area, and oxygen is supplemented through the aeration devices in the first low-oxygen aeration area and the second low-oxygen aeration area, so that nitrifying bacteria inside carry out nitrification reaction;

[0028] The sewage after nitrification reaction enters the air-water backwashing sedimentation area, and sedimentation is carried out in the air-water backwashing sedimentation area for mud-water separation;

[0029] The supernatant of the air-water backwashing sedimentation area enters the MBR membrane area for enhanced treatment.

[0030] Specifically, an air-lift device is also provided in the MBR membrane area, and an air-water backwashing device and a sludge reflux device are provided in the air-water backwashing sedimentation area;

[0031] When the air-lift device and the air-water backwashing device in the MBR membrane area are started synchronously, the air-water backwashing device washes out the flocculent sludge with weak sedimentation performance in the air-water backwashing sedimentation area to the MBR membrane area, and the sludge reflux device refluxes the sludge with low SVI to the influent area;

[0032] After the treatment in the MBR membrane area, the sewage inside is discharged to the second anoxic aeration area through the air-lift device installed therein. That is, with the air-lift device in the MBR membrane area and the air-water backwashing device in the air-water backwashing sedimentation area turned on simultaneously, when the air-water backwashing device is turned on, the flocculent sludge from the anoxic biochemical treatment process with weak sedimentation performance is washed out to the MBR membrane area, while the sludge with strong sedimentation performance and low SVI directly returns to the front-end water inlet area through its own sludge return device. The mud-water mixture entering the MBR membrane area is lifted to the second anoxic aeration area through the air-lift device in the MBR membrane area, thus integrating the membrane treatment process and the anoxic biochemical process, achieving complete consistency of microbial genera. The anoxic biochemical process for other areas except the MBR membrane area is collectively referred to as the anoxic biochemical process for short.

[0033] When the air-lift device and the air-water backwashing device in the MBR membrane area are closed synchronously, the supernatant in the air-water backwashing sedimentation area enters the MBR membrane area and is intensively treated under the action of special bacteria in the MBR membrane area, and the clear water is discharged through the membrane in the MBR membrane area. That is, under the operating condition that the air-water backwashing device in the air-water backwashing sedimentation area is not turned on and the air-lift device in the MBR membrane area is not turned on, its effluent is clear liquid, and then it enters the MBR membrane area, where corresponding special bacteria can be used to intensively treat the characteristic pollutants again. The sludge in the MBR membrane area is intercepted by the membrane filtration, and the clear water is discharged outside the membrane. At the same time, since the air-lift device in the MBR membrane area is not turned on, the microorganisms in the MBR membrane area will not flow into the second anoxic aeration area, which is conducive to separating the microbial genera in the MBR membrane area from the microorganisms in the anoxic biochemical treatment process at the front end of the air-water backwashing sedimentation area, culturing them independently and domestically, without competition. Therefore, finally, special dominant bacteria with unique characteristics can be independently screened and domesticated respectively, and the corresponding characteristic pollutants can be removed respectively.

[0034] In this embodiment, the mud-water mixture in the second anoxic aeration area can also flow into the water inlet area, which is gravity-fed after being lifted by the air-lift devices in the anoxic area and the anaerobic area. Therefore, the sewage is mixed with the nitrified liquid refluxed at the end of the second anoxic aeration area and the reflux sludge in the air-water backwashing sedimentation area in the water inlet area.

[0035] Furthermore, under the combined action of the air-lift devices in the anaerobic area and the anoxic area, the mud-water mixture after the mixing reaction in the water inlet area is carried into the subsequent pre-anoxic area. Through the denitrification of microorganisms in the anoxic environment, while achieving partial nitrogen removal, the combined oxygen in the mud-water mixture can be further reduced, so as to create a more stringent anaerobic phosphorus release environment for phosphorus-removing bacteria after it enters the subsequent anaerobic area, and promote the improvement of biological phosphorus removal efficiency.

[0036] Furthermore, the mixed liquid of mud and water after partial denitrification in the pre-anoxic zone is respectively carried into the subsequent anoxic zone by the air-lift device at the end of the anoxic zone and into the anaerobic zone by the air-lift device at the end of the anaerobic zone; the mixed liquid of mud and water entering the anoxic zone continues denitrification under the action of denitrifying bacteria, and the total nitrogen reaches the discharge standard here. The mixed liquid of mud and water entering the anaerobic zone releases phosphorus under the action of phosphorus-releasing bacteria in the anaerobic zone, creating an essential prerequisite for the subsequent excessive phosphorus absorption in the low-oxygen aeration zone and the MBR membrane zone. The mixed liquid of mud and water in the anaerobic zone is lifted to the front end of the first low-oxygen aeration zone through the anaerobic air-lift device at its end, and the mixed liquid of mud and water in the anoxic zone is also lifted to the front end of the first low-oxygen aeration zone through the air-lift device at its end. There is also an air-lift device in the first low-oxygen aeration zone, and under the action of the gas device, the mixed liquid of mud and water in the second low-oxygen aeration zone flows back to the first low-oxygen aeration zone, that is, part of the mixed liquid of mud and water at the end of the second low-oxygen aeration zone can also be lifted to the front end of the first low-oxygen aeration zone through the air-lift device at the front end of the first low-oxygen aeration zone; moreover, the air-lift devices in the first low-oxygen aeration zone, the anoxic zone, and the anaerobic zone are preferably located on a straight line in design. The air-lift devices in the anoxic zone and the anaerobic zone are both arranged at the connection of the anoxic zone, the anaerobic zone, and the first low-oxygen aeration zone, facilitating the provision of an air power source for these three air-lift devices by the aeration device in the first low-oxygen aeration zone; that is, these three mixed liquids of mud and water all utilize the aeration device at the front end of the first low-oxygen aeration zone to provide an air power source for the lifting of the above three waters while aerating and oxygenating, achieving the true meaning of "one gas for two uses", almost "zero" energy-consuming air-lift reflux, and greatly saving the large amount of energy consumption required for the internal and external reflux of sludge during denitrification and dephosphorization. When the actual operating condition is low load or ultra-low load, by closing the air-lift devices in each zone, even the air-lift device in the membrane zone, some functional zones can be directly short-circuited and bypassed, not participating in the cyclic reaction, which can reduce the effective reaction tank volume actually participating, thereby indirectly increasing the sludge load or volume load and effectively solving the technical problem of the difficult normal operation of low-load or ultra-low load biochemical processes.

[0037] These three mixed liquids of mud and water are quickly mixed and diluted at the front end of the first low-oxygen aeration zone and rely on low-oxygen control (DO ≤ 1mg / l at the end of the low-oxygen zone) here to achieve simultaneous shortcut nitrification and denitrification to remove part of the ammonia nitrogen and total nitrogen. At the same time, polyphosphate-accumulating organisms can also complete the processes of excessive phosphorus absorption biological metabolism and organic matter biological carbonization reaction metabolism here. Another part of the mixed liquid of mud and water after carbon removal, denitrification, and dephosphorization in the second low-oxygen aeration zone enters the subsequent air-water backwashing sedimentation zone to achieve mud-water separation. The sludge separated by sedimentation flows back to the influent zone to continue participating in the reciprocating cyclic metabolism, and its effluent flows through the collection water tank and the effluent channel into the subsequent MBR membrane zone to participate in biological metabolism.

[0038] In this embodiment, under normal circumstances, the dissolved oxygen at the end of the anoxic aeration zone needs to be controlled not higher than 1 mg / l, and preferably controlled below 0.5 mg / l, so as to enable simultaneous short-cut nitrification and denitrification of microorganisms under anoxic conditions in the aerobic zone, thereby endowing the aerobic zone with the new nitrogen removal function of short-cut nitrification and denitrification; the MBR membrane zone is selected to operate with traditional high dissolved oxygen (DO≥1 mg / l) to facilitate the improvement of the removal efficiency and treatment capacity of organic matter and ammonia nitrogen, strengthen the excessive phosphorus absorption of phosphorus-releasing bacteria, and improve the biological phosphorus removal efficiency.

[0039] Furthermore, the anaerobic zone and the anoxic zone in this application operate in parallel, abandoning the traditional series design method, so as to facilitate the control of the return flow of anaerobic sludge and the return flow of anoxic nitrification liquid through their respective air-lift devices respectively, and can also extend the metabolic reaction time of organisms in their respective functional zones, achieving the improvement of the biological nitrogen and phosphorus removal capacity and efficiency. At the same time, by controlling the opening and closing of their respective air-lift devices, short-process operation can be realized, solving the technical problem of the difficult normal operation of the biochemical treatment in sewage treatment plants under low load and ultra-low load.

[0040] Still further, there are no less than 2 groups in the anoxic aeration zone of this application, so that the anoxic zone can realize self-internal circulation pushing and dilution through its own aerobic air-lift device, and finally achieve a perfect flow state that combines pushing flow and complete mixing in the anoxic zone. This flow state can create a low-substrate biological metabolic environment for nitrifying bacteria all year round, which is conducive to the formation of dominant nitrifying bacteria populations, conducive to thorough nitrification, and can greatly improve the removal efficiency and treatment capacity of ammonia nitrogen and total nitrogen.

[0041] In this embodiment, the influent water of the MBR membrane area comes from the effluent water of the air-water backwashing sedimentation area. The magnitude of its influent water volume, compared with the traditional MBR process, not only depends on the actual influent water volume of the front-end anoxic biological nitrogen and phosphorus removal process, but also has an additional air-lift volume of the membrane circulation air-lift device. This is conducive to increasing the upward flow velocity of sedimentation by increasing the reflux flow rate of the membrane circulation air-lift device on the premise of ensuring the designed treatment scale and ensuring stable effluent water quality compliance. Thus, it is possible to preferentially wash out the flocculent activated sludge with poor sedimentation performance and a high SVI value, intercept the return sludge with good sedimentation performance and a low SVI value for sedimentation, and create extremely favorable prerequisite conditions for the high sludge concentration operation of the new anoxic biological nitrogen and phosphorus removal process. Relying on the subsequent membrane interception function, this process can help further directly increase the surface load of the traditional secondary sedimentation tank from the traditional commonly used design value of 0.5 - 0.8 m³ / m²·h to not less than 0.8 m³ / m²·h or more, greatly improving the surface load of the traditional sedimentation tank and reducing the investment of the traditional sedimentation tank. The flocculent activated sludge with poor sedimentation performance and a high SVI value that enters the membrane tank is modified in terms of its sedimentation performance after adding nutrients to the membrane tank, and then reflows to the new anoxic biological nitrogen and phosphorus removal process through the membrane circulation air-lift reflux device, which can further increase its sludge concentration, is conducive to maintaining the high sludge concentration operation of the anoxic biological nitrogen and phosphorus removal process throughout the year to improve its treatment capacity and removal efficiency, and is also conducive to achieving aerobic granulation of activated sludge under anoxic conditions. In addition, since the influent water of the MBR membrane area comes from the sedimentation effluent, it can prevent the entanglement and fouling of the membrane filaments by the sundries in the sewage, further greatly reducing the degree of membrane fouling, improving the membrane flux, and extending the service life of the membrane.

[0042] Furthermore, according to the actual operating conditions, when the membrane circulation air-lift device is shut down in the MBR membrane area, the activated sludge in the MBR membrane area no longer participates in the cyclic treatment of the new anoxic biological nitrogen and phosphorus removal process. Therefore, it can operate independently of each other without interference and be transformed into series operation, equivalent to two-stage treatment. Therefore, for the characteristic pollutants that are difficult to biodegrade in the sewage industry field, we can inoculate and expand the culture of highly efficient strains, introduce special strains in the membrane tank, and then use these special microorganisms to strengthen the removal of some characteristic pollutants that cannot be biodegraded by the front-end new anoxic biological nitrogen and phosphorus removal process, providing an independent optimal metabolic environment conducive to their becoming dominant flora. Therefore, it is possible to find an optimal short-process biological metabolism technology solution for the efficient removal of characteristic pollutants that are difficult to biodegrade.

[0043] In this embodiment, for some special industrial fields and for the characteristic pollutants in such sewage that are difficult to be biodegraded by biochemical methods, the present invention can also turn off the air-lifting device in the MBR membrane area to prevent the activated sludge in the membrane area from participating in the recycling treatment. Therefore, for the characteristic pollutants in the sewage industry that are difficult to be biochemically degraded, we can inoculate and expand the culture of highly efficient strains, introduce such special strains into the membrane area in a targeted manner, and utilize their particularity to strengthen the biochemical degradation of some characteristic pollutants that cannot be degraded by the novel anoxic biological nitrogen and phosphorus removal process at the front end, and finally achieve up-to-standard discharge. This flexible switching design method that can be independent or in series through one area creates extremely favorable conditions for creating the best biological survival and metabolic environment for cultivating their respective dominant bacterial populations. Therefore, by turning on and off the air-lifting device in the MBR membrane, a best short-process biological metabolism technology solution can be found for efficiently removing characteristic pollutants that are difficult to be biochemically degraded according to the actual operating conditions requirements.

[0044] This application gives full play to the novel anoxic biological nitrogen and phosphorus removal process under anoxic conditions, which combines synchronous short-cut nitrification and denitrification with an almost "zero-consumption" membrane air-lifting circulation device to achieve sludge reflux in the MBR process. While achieving low-oxygen biological nitrogen removal in the traditional MBR process and thus achieving energy-saving and low-carbon operation, it can also, through the synergistic effect of sedimentation filtration of the novel anoxic biological nitrogen and phosphorus removal process and large-scale air-lifting reflux flushing of the membrane circulation, improve the membrane flux, reduce membrane fouling, extend the membrane service life and reduce the membrane investment. It can still give full play to the technical advantages of the traditional MBR membrane process, such as high sludge concentration, short process and excellent effluent quality, and achieve stable up-to-standard discharge of sewage throughout the year.

[0045] In addition, this application can also be extended through a series operation mode to introduce special strains into the membrane tank, and can play the technical advantage of the degradation specificity of special strains for characteristic pollutants that are difficult to be biochemically degraded, and further degrade them to improve the removal efficiency and treatment capacity of the biochemical system. At the same time, other auxiliary technical means such as adding biological fillers, adsorbents or oxidants to the membrane tank can also be used together to further improve the effluent quality of the traditional MBR process and achieve zero discharge and resource recycling of sewage. Through this MBR combined process flow coupling the novel anoxic biological nitrogen and phosphorus removal process, it can not only completely solve the above-mentioned relatively difficult and intractable technical problems faced in the wide engineering promotion and application, such as large investment in membrane components, high operating energy consumption and difficult membrane fouling control, but also enable the membrane technology to truly achieve both "affordable to build and affordable to use", move towards energy-saving and low-carbon operation, and promote the more rapid popularization and application of the membrane technology in the sewage treatment industry.

[0046] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An MBR membrane bioreactor sewage treatment process, characterized in that, it includes: The sewage first enters the influent area, and the oxygen in the sewage is eliminated under the metabolic action of microorganisms; Start the air-lift devices in the anoxic area and the anaerobic area. The sewage enters the pre-anoxic area from the influent area, and the combined nitrogen in the sewage is degraded through the denitrification reaction of the microorganisms and the oxygen in the sewage is continuously eliminated; After that, it enters the anoxic area and the anaerobic area respectively. The denitrification reaction is carried out under the action of denitrifying bacteria in the anoxic area, and the phosphorus release reaction is carried out under the action of phosphorus-releasing bacteria in the anaerobic area; Then, the sewage flowing out from the anoxic area and the anaerobic area converges and sequentially passes through the first low-oxygen aeration area and the second low-oxygen aeration area. And oxygen is supplemented through the aeration device in the first low-oxygen aeration area and the second low-oxygen aeration area, and the dissolved oxygen in the first low-oxygen aeration area and the second low-oxygen aeration area is controlled not to be higher than 1 mg / l, creating conditions for the synchronous short-cut nitrification and denitrification mainly in the nitrification reaction inside; The sewage after the nitrification reaction enters the air-water backwashing sedimentation area, and sedimentation is carried out in the air-water backwashing sedimentation area for sludge-water separation; The supernatant of the air-water backwashing sedimentation area enters the MBR membrane area for enhanced treatment; An air-lift device is also provided in the MBR membrane area, and an air-water backwashing device and a sludge reflux device are provided in the air-water backwashing sedimentation area; When the air-lift device in the MBR membrane area and the air-water backwashing device are synchronously started, the air-water backwashing device washes out the flocculent sludge with weak sedimentation performance in the air-water backwashing sedimentation area to the MBR membrane area, and the sludge reflux device refluxes the sludge at the bottom of the air-water backwashing sedimentation area with low SVI to the influent area; The sewage inside the MBR membrane area is discharged to the second low-oxygen aeration area through the air-lift device provided therein after treatment; When the air-lift device in the MBR membrane area and the air-water backwashing device are synchronously closed, the supernatant of the air-water backwashing sedimentation area enters the MBR membrane area, and is intensively treated under the action of special bacteria in the MBR membrane area, and the clear water is discharged through the membrane of the MBR membrane area.

2. The MBR membrane bioreactor sewage treatment process according to claim 1, characterized in that, The mud-water mixture in the second low-oxygen aeration area is refluxed to the influent area.

3. The MBR membrane bioreactor sewage treatment process according to claim 1, characterized in that, An air-lift device is also provided in the first low-oxygen aeration area, and under the action of the air-lift device, the mud-water mixture in the second low-oxygen aeration area is refluxed to the first low-oxygen aeration area.

4. The MBR membrane bioreactor sewage treatment process according to claim 3, characterized in that, The air-lift devices in the anoxic area and the anaerobic area are both arranged at the connection of the anoxic area, the anaerobic area and the first low-oxygen aeration area, and the air-lift devices in the anoxic area, the anaerobic area and the first low-oxygen aeration area all obtain the air power source through the aeration device in the first low-oxygen aeration area.

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