AMAO sewage treatment method and system

Abstract

The invention discloses an AMAO sewage treatment method and system, and the method comprises the following steps: carrying out anaerobic treatment on feed sewage to obtain anaerobic treatment effluent; the anaerobic treatment effluent is subjected to MABR treatment, and MABR treatment effluent is obtained; carrying out at least one time of oxygen elimination-aerobic treatment on the MABR effluent to obtain oxygen elimination-aerobic treatment effluent; carrying out precipitation treatment on the effluent subjected to the oxygen elimination-aerobic treatment to obtain product water; the oxygen elimination-aerobic treatment comprises oxygen elimination treatment and aerobic treatment which are sequentially carried out; carrying out at least one time of oxygen elimination-aerobic treatment on at least part of the oxygen elimination-aerobic treatment effluent; and carrying out anaerobic treatment on at least part of the sludge obtained by the precipitation treatment. The AMAO sewage treatment method provided by the invention has the characteristics of relatively good effluent quality, relatively low system retention time and relatively low operation energy consumption.

Description

Technical Field

[0001] The present invention relates to the field of environmental engineering, and in particular to an AMAO sewage treatment method and system. Background Art

[0002] Urban sewage treatment is an important issue in the current urbanization process. Urban sewage has the characteristics of large changes in water quality, large changes in water volume, many types of pollutants, and large fluctuations in pollutant concentrations. In view of these characteristics of urban sewage, it is necessary to adopt appropriate sewage treatment technologies and processes to ensure that sewage is effectively treated and meets emission standards. Although sewage treatment plants are responsible for the green mission of improving effluent water quality standards and reducing water environment problems such as black and odorous water bodies and eutrophication, my country's current urban sewage treatment plants have problems such as long biochemical treatment process, large land area, high aeration energy consumption, and high operating costs. The sewage treatment model of "exchanging energy consumption for water quality" makes it inevitable for the equipment to produce certain carbon emissions during operation, and there is also a risk of transferring water pollution to air pollution.

[0003] In order to reduce the residence time of the biochemical unit and reduce the floor space, many sewage treatment plants use the MBR process, but this process has the defect of high energy consumption. Specifically, the MBR mud-water separation process must maintain a certain membrane driving pressure. In order to increase the membrane flux and reduce membrane pollution, it is necessary to increase the aeration volume to increase the liquid flow rate and flush the membrane surface, resulting in higher energy consumption of MBR than traditional biological treatment processes. At the same time, the MLSS concentration in the MBR pool is very high. To maintain a sufficient oxygen transfer rate, the aeration intensity must be increased. The increase in sludge concentration also means an increase in the amount of air blown, so the operating energy consumption is much greater than that of traditional processes.

[0004] At the same time, some water plants also use MBBR technology. The core of MBBR is to increase the filler. The uniquely designed filler floats with the water flow in the reaction tank under the disturbance of aeration, driving the attached and growing biological flora to fully contact the pollutants and oxygen in the water body. The pollutants enter the biofilm through adsorption and diffusion and are degraded by microorganisms. The attached and growing microorganisms can reach a very high biomass, so the biological concentration in the reaction tank is several times that of the suspended growth activated sludge process, and the pollutant removal efficiency is also increased exponentially. However, the disadvantages of the MBBR process are (1) the filler in the reactor needs to rely on the lifting effect of aeration and water flow to be in a fluidized state. In actual projects, local filler accumulation is prone to occur. In order to avoid filler accumulation, the layout of the aeration pipeline and the structure of the reactor need to be improved. The structure of the reactor largely determines its hydraulic characteristics. In actual projects, when the length-to-depth ratio of a single reactor is about 0.5 and the length is not more than 3m, it is conducive to the complete fluidization of the filler. In actual project design, a large number of tests should be carried out to optimize the structure and hydraulic characteristics of the reactor. (2) The effluent of the reactor is often equipped with a grid or mesh to prevent the loss of filler, but it is easy to cause blockage. (3) The problem of filler damage. After several years of operation, some MBBR sewage plants have caused filler damage due to friction and collision between fillers and between fillers and the pool wall. On the one hand, it affects the operation effect of the system. On the other hand, filler fragments will also enter the secondary sedimentation tank, deep treatment unit, etc., affecting the operation of the equipment.

[0005] In traditional sewage treatment plants, ammonia nitrogen removal is achieved through aeration in aerobic tanks. The automatic control of aeration volume is based on ammonia nitrogen aeration control through front feedback or back feedback. However, this aeration method is too rough and can easily lead to excessive aeration, energy waste, or too low aeration volume after feedback, resulting in substandard ammonia nitrogen in the system effluent.

[0006] MABR technology is a new type of low-carbon sewage treatment technology that combines gas separation membrane technology with biofilm water treatment technology. The core parts include oxygen permeable membrane and biofilm. The biofilm grows on the outer surface of the oxygen permeable membrane. Air / oxygen supplies oxygen to the biofilm through the oxygen permeable membrane, and the organic matter and nitrogen and phosphorus contained in the sewage are adsorbed, absorbed and decomposed by the biofilm, so that the sewage is purified. This new technology belongs to a new type of low-carbon sewage treatment technology. With the deepening of MABR research, due to the high oxygen mass transfer efficiency of MABR, it has received more and more attention in ammonia oxidation, simultaneous nitrification and denitrification, and enhanced biological denitrification.

[0007] However, there are still some problems that restrict the promotion and application of MABR technology in the process of engineering application. On the one hand, in the traditional sewage treatment process, the MABR membrane components are directly installed in the biochemical pool and are simply used in series. The MABR and activated sludge processes do not achieve performance superposition coupling. For example, in the traditional process design process, the MABR membrane components are directly installed in the anoxic pool. This design method cannot fully utilize the MABR's own ability to remove high-concentration ammonia nitrogen and the advantages of simultaneous nitrification and denitrification, and it also fails to achieve the purpose of reducing the operating energy consumption, residence time, and floor space of the traditional sewage treatment process. At the same time, the introduction of MABR also adds additional investment costs.

[0008] On the other hand, in the actual engineering application process of MABR, scientific gas supply parameters have not yet been formed, and there is still a phenomenon of extensive operation. The gas supply per unit membrane area of ​​the MABR unit also determines the quality of the denitrification effect. If the gas supply is too large, on the one hand, it will lead to energy waste and affect the anoxic environment of the unit where the MABR is located, which will in turn affect the denitrification effect. If the gas supply is too small, it is difficult to gather nitrifying bacteria on the surface of the MABR membrane. At the same time, after long-term operation, the surface of the MABR membrane has insufficient oxygen content, which causes heterotrophic bacteria to grow on the surface of the MABR membrane, making it impossible for MABR to play the advantage of high oxygen mass transfer efficiency and causing the membrane fibers to be blocked.

[0009] At the same time, MABR itself is a biofilm treatment process, and its high oxygen mass transfer efficiency proves that it has great advantages in ammonia oxidation. In principle, the higher the ammonia nitrogen concentration of the MABR unit substrate, the higher the ammonia nitrogen removal capacity of MABR, and the more conducive it is to reducing the aeration energy consumption of the aerobic tank and the system residence time. However, the existing MABR engineering applications are just a simple series connection of MABR and traditional processes, and there is no targeted optimization design for the reflux volume and reflux method, which leads to a significant dilution of the ammonia nitrogen in the MABR influent, and the nitrification performance advantage under high ammonia nitrogen concentration is not brought into play.

[0010] Therefore, developing a sewage treatment system and method with good effluent quality, low energy consumption and short system residence time has become a research direction. Summary of the invention

[0011] The present invention provides an AMAO sewage treatment method, which has the characteristics of achieving better effluent water quality while reducing system residence time and operating energy consumption.

[0012] The present invention also provides an AMAO sewage treatment system, which has the characteristics of achieving better effluent water quality while reducing system residence time and operating energy consumption.

[0013] The present invention provides an AMAO sewage treatment method, which comprises the following steps:

[0014] Anaerobic treatment is performed on the feed sewage to obtain anaerobic treatment effluent;

[0015] Performing MABR treatment on the anaerobic treatment effluent to obtain MABR treated effluent;

[0016] The MABR treated effluent is subjected to at least one deoxygenation-aerobic treatment to obtain deoxygenation-aerobic treated effluent;

[0017] Performing sedimentation treatment on the effluent from the deoxidation-aerobic treatment to obtain product water;

[0018] The deoxygenation-aerobic treatment includes deoxygenation treatment and aerobic treatment performed sequentially;

[0019] Performing at least one oxygen-aerobic treatment on at least a portion of the oxygen-aerobic treatment effluent;

[0020] Anaerobic treatment of at least part of the sludge obtained from the sedimentation treatment;

[0021] The MABR treatment is carried out using a MABR membrane module;

[0022] The MABR membrane assembly comprises a MABR membrane, wherein the MABR membrane is selected from at least one of a hollow fiber membrane, a plate membrane, a roll membrane, and a tubular membrane;

[0023] The MABR treatment includes contacting the anaerobic treatment effluent with the MABR membrane assembly to obtain the MABR treatment effluent.

[0024] The AMAO wastewater treatment method as described above, wherein, in the anaerobic treatment, the redox potential of the treatment system is -300mV to -150mV; and / or,

[0025] In the MABR treatment, the redox potential of the treatment system is -100mV~0mV; and / or,

[0026] In the deoxidation treatment, the oxidation-reduction potential of the treatment system is -150mV to -50mV; and / or,

[0027] In the aerobic treatment, the redox potential of the treatment system is 100mV~300mV.

[0028] The AMAO sewage treatment method as described above, wherein the hydraulic retention time of the MABR treatment is 2 to 4 hours; and / or,

[0029] The hydraulic retention time of the deoxygenation treatment is 1 to 3 hours; and / or,

[0030] The hydraulic retention time of the aerobic treatment is 1 to 2 hours; and / or,

[0031] The flow ratio of at least part of the sludge to the feed sewage is 0.8-1.2.

[0032] The AMAO sewage treatment method as described above, wherein the method further includes obtaining the oxygen content in the gas entering and leaving the MABR membrane assembly, calculating the MABR oxygen transfer efficiency using Formula 1 and Formula 2, and calculating the gas supply per unit membrane area of ​​the MABR membrane assembly using Formula 3 according to the MABR oxygen transfer efficiency;

[0033] Formula 1;

[0034] Formula 2;

[0035] Formula 3;

[0036] OTE: MABR oxygen transfer efficiency;

[0037] : The oxygen content in the gas entering the MABR membrane module;

[0038] : Gas volume loss coefficient;

[0039] : The oxygen content in the gas leaving the MABR membrane module;

[0040] : Gas supply per unit membrane area of ​​MABR membrane module, Nm 3 / m 2 / h.

[0041] The AMAO wastewater treatment method as described above, wherein the MABR effluent is subjected to a first deoxygenation treatment, a first aerobic treatment, a second deoxygenation treatment, and a second aerobic treatment in sequence to obtain deoxygenation-aerobic treatment effluent;

[0042] The method also includes subjecting at least a portion of the feed wastewater to a second deoxygenation treatment.

[0043] In the AMAO wastewater treatment method as described above, the volume ratio of the feed wastewater for the anaerobic treatment to the feed wastewater for the second deoxidation treatment is 3:(1-2).

[0044] The present invention also provides an AMAO sewage treatment system, which is used to perform any of the above-mentioned AMAO sewage treatment methods, wherein the system comprises an anaerobic tank, a MABR tank, at least one anaerobic-aerobic unit, and a sedimentation tank;

[0045] The deoxidation-aerobic unit comprises a deoxidation tank and an aerobic tank which are connected in sequence;

[0046] The outlet of the anaerobic tank is connected to the inlet of the MABR tank;

[0047] The outlet of the MABR tank is connected to the inlet of the oxic-aerobic unit;

[0048] The outlet of the oxygen-dissipation-aerobic unit at the end is respectively connected to the inlet of the sedimentation tank and the inlet of the oxygen-dissipation-aerobic unit at the head end;

[0049] The MABR tank includes a MABR membrane module;

[0050] The sludge outlet of the sedimentation tank is communicated with the sludge inlet of the anaerobic tank.

[0051] The AMAO sewage treatment system as described above, wherein the dissolved oxygen concentration of the anaerobic tank is 0-0.2 mg / L, the dissolved oxygen concentration of the MABR tank is 0.2-0.5 mg / L, and the dissolved oxygen concentration of the aerobic tank is 1.5-2.5 mg / L; and / or,

[0052] The filling area of ​​the MABR membrane module is 6~15m 2 / m 3 Feed sewage;

[0053] The scrubbing intensity of the MABR membrane assembly is 15-30s / h, and the scrubbing gas volume is 3-8Nm 3 / h.

[0054] In the AMAO wastewater treatment system as described above, the MABR tank is also provided with an oxygen concentration sensor for respectively obtaining the oxygen content in the gas entering and leaving the MABR membrane assembly.

[0055] The AMAO sewage treatment system as described above, wherein, comprises an anaerobic tank, a MABR tank, a first oxygen elimination tank, a first aerobic tank, a second oxygen elimination tank, a second aerobic tank, and a sedimentation tank;

[0056] The outlet of the anaerobic tank is connected to the inlet of the MABR tank;

[0057] The outlet of the MABR tank is connected to the inlet of the first oxygen elimination tank;

[0058] The outlet of the first oxygen elimination tank is connected to the inlet of the first aerobic tank;

[0059] The outlet of the first aerobic tank is connected to the inlet of the second oxygen elimination tank;

[0060] The outlet of the second oxygen elimination tank is connected to the inlet of the second aerobic tank;

[0061] The outlet of the second aerobic tank is communicated with the inlet of the first oxygen elimination tank and the inlet of the sedimentation tank respectively.

[0062] The AMAO sewage treatment method provided by the present invention gives full play to the advantages of MABR and activated sludge method, can realize partial ammonia nitrogen removal under low energy consumption conditions in the MABR area, and fully utilizes the organic carbon source in the influent to realize simultaneous nitrification and denitrification, without relying on the addition of external carbon source agents, thereby improving the denitrification effect of the system and making the effluent water quality better; in terms of MABR design and control, the present invention also provides a model for calculating the filling area of ​​MABR according to the treated water volume, so as to avoid the waste of investment caused by filling too large membrane area, and avoid the influence of too small membrane area on the denitrification effect of the system; at the same time, the present invention provides an operating parameter model of the air supply per unit membrane area of ​​MABR, which can adjust the MABR air supply according to the oxygen content in the MABR inlet and tail gas, so as to avoid the problem of too large or too small air supply of MABR; during the operation of MABR, it provides appropriate scrubbing intensity, The frequency parameter avoids the problems of aging, shedding and biofilm difficulty of microorganisms on the surface of MABR biofilm; and the present invention fully combines the advantages and characteristics of MABR and activated sludge process, provides conditions such as reflux mode and reflux volume, avoids the dilution of ammonia nitrogen in the influent of the structure used for MABR treatment by the traditional reflux mode, and the higher ammonia nitrogen concentration of the structure used for MABR treatment further enhances the ammonia nitrogen removal capacity of MABR, and avoids the influence of large internal reflux on the anoxic environment of the anoxic tank and the waste of reflux energy consumption, thereby realizing the complete coupling of the system; at the same time, by taking advantage of the high oxygen mass transfer efficiency of MABR, autotrophic and heterotrophic denitrification pathways such as short-range nitrification and denitrification, synchronous nitrification and denitrification are realized on the surface of MABR biofilm, which greatly reduces the dependence on carbon sources in the influent, and at the same time reduces the dependence on external carbon sources, which is suitable for low C / N ratio sewage treatment. At the same time, the efficient removal of ammonia nitrogen by the structure used for MABR treatment also further reduces the ammonia nitrogen concentration entering the aerobic tank, so it can also greatly save the volume and aeration volume of the aerobic tank and reduce the operating energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced one by one below. Obviously, the drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0064] Figure 1 An equipment diagram of the first AMAO sewage treatment system provided by the present invention;

[0065] Figure 2 The equipment diagram of the second AMAO sewage treatment system provided by the present invention;

[0066] Figure 3 Equipment diagram of the sewage treatment system used for the comparative example;

[0067] Figure 4 Total nitrogen removal data for the embodiment;

[0068] Figure 5 This is a graph showing the relationship between the oxygen content in the gas leaving the MABR pool and the ammonia nitrogen concentration in the MABR pool inlet water.

[0069] Description of reference numerals:

[0070] 100-anaerobic tank;

[0071] 200-MABR Pool;

[0072] 300-the first oxygen elimination tank;

[0073] 400-First aerobic pool;

[0074] 500-Sedimentation tank;

[0075] 600- The second oxygen elimination pool;

[0076] 700-Second aerobic pool. DETAILED DESCRIPTION

[0077] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0078] The current sewage treatment has the defect of high energy consumption. The inventors analyzed that the reason may be that the existing sewage treatment technology has a long process flow, so the aeration energy consumption is high. Therefore, if a sewage treatment method with a shorter process flow can be developed under the premise of ensuring the effluent quality, the above problem can be solved.

[0079] Based on this, the first aspect of the present invention provides an AMAO sewage treatment method, the method comprising the following steps:

[0080] Anaerobic treatment is performed on the feed sewage to obtain anaerobic treatment effluent;

[0081] Performing MABR treatment on the anaerobic treatment effluent to obtain MABR treated effluent;

[0082] The MABR treated effluent is subjected to at least one deoxygenation-aerobic treatment to obtain deoxygenation-aerobic treated effluent;

[0083] The effluent from the deoxidation-aerobic treatment is subjected to sedimentation treatment to obtain product water;

[0084] The oxic-aerobic treatment includes oxic treatment and aerobic treatment carried out in sequence;

[0085] Performing at least one oxygen-aerobic treatment on at least a portion of the oxygen-aerobic treatment effluent;

[0086] anaerobic treatment of at least a portion of the sludge obtained from the sedimentation treatment;

[0087] MABR treatment is carried out using MABR membrane modules;

[0088] The MABR membrane assembly includes a MABR membrane, and the MABR membrane is selected from at least one of a hollow fiber membrane, a plate membrane, a roll membrane, and a tubular membrane;

[0089] The MABR treatment includes contacting the anaerobic treatment effluent with the MABR membrane assembly to obtain the MABR treatment effluent.

[0090] The feed sewage is also the sewage to be treated. It is understandable that, for the convenience of treatment, the sewage has been pre-treated, for example, by removing impurities in a screen and removing part of the suspended solids in a primary sedimentation tank.

[0091] AMAO is the abbreviation of Anaerobic-MABR-Anoxic-Aerobic, which represents anaerobic, MABR, anaerobic (anoxic) treatment and aerobic treatment in sequence.

[0092] The feed wastewater is first treated anaerobically to obtain anaerobic treatment effluent. During the anaerobic treatment process, microorganisms hydrolyze organic matter and release phosphorus anaerobically. Specifically, microorganisms can decompose macromolecular organic matter (such as carbohydrates, fats and proteins) into biodegradable short-chain fatty acids (VFA) under the action of anaerobic bacteria in an anaerobic environment. Polyphosphate-accumulating bacteria (PAOs) use the short-chain fatty acids in the raw water and the hydrolyzed short-chain fatty acids as carbon and energy sources in an anaerobic environment. While the organic matter is being decomposed, the polyphosphate-accumulating bacteria will release the polyphosphate stored in the body into the liquid phase to release phosphorus:

[0093] .

[0094] The present invention does not limit the specific conditions of anaerobic treatment, and common process conditions in the industry can be adopted.

[0095] Subsequently, the anaerobic treatment effluent is subjected to MABR treatment to obtain MABR treated effluent. MABR treatment includes contacting the anaerobic treatment effluent with a MABR membrane assembly to obtain MABR treated effluent, and the treatment is carried out using a MABR membrane assembly, which includes a MABR membrane, and the MABR membrane is selected from at least one of a hollow fiber membrane, a plate membrane, a roll membrane, and a tubular membrane. MABR (Membrane Aerated Biofilm Reactor) is a sewage treatment technology that combines membrane technology and biofilm method. It uses a special oxygen permeable membrane to provide oxygen and serves as an attachment carrier for the biofilm, so that the biofilm method is combined with membrane aeration technology, thereby optimizing the oxygen mass transfer efficiency and the removal efficiency of pollutants. MABR uses a breathable membrane (at least one of a hollow fiber membrane, a plate membrane, a roll membrane, and a tubular membrane) as a core component. One side of the membrane is in contact with the air, and oxygen is transported to the biofilm on the other side through the micropores of the membrane without directly generating bubbles. Therefore, oxygen gradually diffuses from one side of the membrane into the biofilm and is absorbed by the microorganisms in the biofilm.

[0096] This oxygen permeability characteristic significantly improves the efficiency of oxygen utilization. At the same time, since oxygen diffuses from the membrane rather than being directly aerated into the water, it avoids a lot of energy consumption and oxygen waste in the traditional aeration process.

[0097] In the MABR system, a layer of attached biofilm is formed on the outside of the membrane. Sewage passes through the surface of the biofilm, and pollutants dissolved in the water (such as ammonia nitrogen and organic matter) enter the biofilm through diffusion and undergo biochemical reactions with the microorganisms in the biofilm:

[0098] Ammonia oxidation: The membrane surface close to the oxygen permeable membrane is the aerobic zone. Due to the sufficient supply of oxygen, aerobic microorganisms (such as ammonia oxidizing bacteria AOB) can oxidize ammonia nitrogen into nitrite and then further oxidize it into nitrate.

[0099] Denitrification: In the outer layer of the biofilm, the oxygen concentration is low and some areas become anoxic environments, where denitrification reactions occur. Nitrates are converted into nitrogen gas by heterotrophic denitrifying bacteria and eventually released into the air in the form of bubbles.

[0100] Specifically, the surface of the MABR membrane and the liquid phase area where the membrane assembly is located are in an anaerobic state, and an autotrophic-heterotrophic synergistic denitrification reaction process occurs in the MABR area. Among them, on the surface of the MABR membrane, due to the air supply inside the membrane cavity, the area close to the membrane surface is in an aerobic state, and an ammonia oxidation process occurs under the action of ammonia oxidizing bacteria (AOB), oxidizing part of the ammonia nitrogen into nitrite, and under the action of nitrite oxidizing bacteria (NOB), part of the generated nitrite is oxidized into nitrate.

[0101] In the liquid phase environment treated by MABR, on the one hand, when the carbon source in the incoming water is sufficient for heterotrophic denitrification, the nitrate produced by the sludge return and the MABR membrane surface undergoes heterotrophic denitrification with the biodegradable organic matter (COD) in the incoming water, reducing the nitrate to nitrogen. On the other hand, under low carbon source conditions, under the action of anaerobic ammonia-oxidizing bacteria (AnAOB), part of the nitrite produced by the oxidation of AOB bacteria on the MABR membrane surface is freed into the liquid phase and converted into nitrogen together with the ammonia nitrogen in the liquid phase.

[0102] In the MABR treated effluent obtained by the MABR treatment, some COD and ammonia nitrogen are not removed, so it is necessary to further perform at least one deoxygenation-aerobic treatment to obtain deoxygenation-aerobic treated effluent. The deoxygenation-aerobic treatment includes deoxygenation treatment and aerobic treatment performed sequentially.

[0103] The deoxygenation treatment effectively utilizes the remaining organic carbon source to carry out denitrification reaction, further reducing the nitrogen content in the sewage. During this treatment process, the COD in the sewage undergoes a heterotrophic denitrification reaction with nitrates, reducing the nitrates to nitrogen gas. Part of the nitrate used in the deoxygenation treatment comes from the effluent from the MABR treatment, and the other part comes from the internal reflux water obtained from the effluent from the deoxygenation-aerobic treatment. The present invention does not limit the specific treatment conditions of the deoxygenation treatment, and the process conditions commonly used in the industry can be used. In one embodiment, the deoxygenation treatment can use the same treatment conditions as the anoxic treatment commonly used in the industry.

[0104] Aerobic treatment plays two main roles: First, through aerobic treatment, polyphosphate bacteria (PAOs) fully absorb phosphates in sewage and store them in cells, and discharge them from the system during the sludge discharge process, while further removing ammonia nitrogen, enhancing the redox potential in the water, and promoting the decomposition of some difficult-to-decompose organic matter; more importantly, through a small amount of short-term aeration, the bubbles or nitrogen near the sludge are blown off, and through aeration, the collision and combination between sludge particles are enhanced, promoting flocculation, and forming larger and more compact precipitation particles. This ensures the rapid separation of mud and water in subsequent treatment.

[0105] The present invention does not limit the specific number of times of deoxygenation-aerobic treatment, which can be selected according to the needs, and the requirement of first performing deoxygenation treatment and then performing aerobic treatment can be met. For example, in one embodiment, the specific number of times of deoxygenation-aerobic treatment is 2, and the MABR effluent is sequentially subjected to the first deoxygenation treatment, the first aerobic treatment, the second deoxygenation treatment, and the second aerobic treatment.

[0106] Subsequently, the effluent from the aerobic-oxidative treatment is subjected to sedimentation treatment to obtain product water. The sedimentation treatment is used to separate the effluent from the aerobic-oxidative treatment into mud and water, and the supernatant is the product water. Of the sludge obtained from the sedimentation treatment, at least a portion of the sludge is refluxed to continue the anaerobic treatment, and the other portion is discharged through the sludge discharge.

[0107] In addition, the method provided by the present invention further comprises performing at least one aerobic-oxidative treatment on at least part of the effluent from the aerobic-oxidative treatment. It is understandable that, since the present invention does not limit the number of times the aerobic-oxidative treatment is performed, the above process actually returns the aerobic-oxidative treatment effluent obtained from the last aerobic-oxidative treatment to the front end of the structure that performs the first aerobic-oxidative treatment, so that the reflux water is subjected to the first to the last aerobic-oxidative treatment in sequence.

[0108] After the aerobic-aerobic treatment effluent is refluxed, the aerobic-aerobic treatment can be performed again. On the one hand, the COD in the MABR treatment effluent can be further used for denitrification; on the other hand, in the existing process, the aerobic treatment effluent is usually refluxed to the rear end of the anaerobic treatment and the front end of the anoxic treatment, that is, the front end of the MABR treatment. In this case, after the aerobic-aerobic treatment effluent is fully mixed and diluted with the influent, the ammonia nitrogen concentration of the MABR treatment influent will be greatly reduced, and the influent volume of the MABR area will increase, thereby shortening the residence time, low influent ammonia nitrogen concentration, short residence contact time, which will make the performance advantages of the microorganisms on the membrane surface and the liquid phase microorganisms in the MABR area unable to be brought into play. In the present invention, the aerobic treatment effluent is refluxed to the rear end of the MABR treatment and the front end of the aerobic treatment, so that the ammonia nitrogen concentration of the MABR treatment influent is not diluted, and the ammonia nitrogen concentration of the incoming water is reduced, and then the richer AOB and NOB bacteria can be cultivated in the MABR treatment, thereby improving the autotrophic-heterotrophic synergistic denitrification effect of the MABR treatment.

[0109] Furthermore, the flow ratio of the effluent from the aerobic-aerobic treatment to the feed sewage can be controlled to be less than or equal to 1.2 to maintain system balance, that is, the return ratio is controlled to be less than or equal to 120%. This return ratio can effectively avoid system dilution caused by excessive return flow and ensure that the reaction conditions in the anaerobic and anoxic zones remain stable. An appropriate return flow can improve the denitrification effect by returning part of the nitrified effluent to the aerobic zone to promote the denitrification process, thereby reducing the total nitrogen concentration in the effluent.

[0110] The AMAO sewage treatment method provided by the present invention gives full play to the advantages of MABR, realizes autotrophic-heterotrophic synergistic denitrification in the MABR area, fully utilizes the organic carbon source in the influent, does not need to rely on the addition of external carbon source agents, improves the denitrification effect of the system, and makes the effluent water quality better; at the same time, the method can also greatly save the volume of the aerobic tank and the aeration volume, and reduce the operating energy consumption.

[0111] In one embodiment, the redox potential (ORP) of the system is controlled at -300mV~-150mV during anaerobic treatment, which helps to create an environment conducive to the activity of anaerobic microorganisms, especially suitable for the growth of polyphosphate bacteria (PAOs) and acid-producing bacteria. Within this ORP range, the system is reductive, which is conducive to the anaerobic decomposition of organic matter and the production of short-chain fatty acids (VFA), as well as the release reaction of phosphorus. Polyphosphate bacteria accumulate energy by releasing phosphorus in this environment, preparing for phosphorus absorption in the subsequent aerobic stage. This anaerobic control ensures the dominance of anaerobic bacteria by reducing the presence of oxygen and oxidizing substances, thereby improving the treatment effect of phosphorus and organic pollutants.

[0112] Furthermore, in MABR treatment, controlling the redox potential (ORP) of the system between -100mV and 0mV can effectively achieve the synergistic denitrification effect of autotrophic and heterotrophic microorganisms. This ORP range is from facultative anaerobic to slightly anoxic, which is suitable for the joint action of ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and some denitrifying bacteria. In the membrane aerated bioreactor, the oxygen permeable membrane provides a local aerobic environment, supporting ammonia oxidation and nitrite oxidation near the membrane; while the outer layer maintains a facultative anaerobic state due to limited oxygen diffusion, which is conducive to the denitrifying bacteria using organic carbon sources to reduce nitrate and nitrite to nitrogen gas. Through this fine ORP control, simultaneous nitrification and denitrification (SND) is achieved, improving the denitrification efficiency while reducing the high energy consumption required for traditional aerobic treatment.

[0113] At the same time, in the deoxygenation treatment, the redox potential (ORP) of the system is controlled at -150mV to -50mV to achieve an efficient denitrification process. Within this ORP range, the environment is in an anaerobic to slightly anoxic state, which is suitable for the activity of heterotrophic denitrifying bacteria, enabling them to reduce nitrates to nitrogen gas, thereby effectively removing nitrogen pollutants from sewage. At this time, there is a certain amount of organic carbon source in the system as an electron donor, and the nitrogen in the nitrate is released as nitrogen gas to escape into the air through the denitrification process. Controlling in this ORP range ensures that the denitrifying bacteria are in the most suitable metabolic environment, maximizing the denitrification efficiency while reducing energy consumption.

[0114] In order to make the sewage treatment method provided by the present invention have better effluent water quality, the hydraulic retention time of MABR treatment can be controlled between 2 and 4 hours, and the above hydraulic retention time can achieve effective synergy between autotrophic and heterotrophic microorganisms. In MABR treatment, oxygen is provided by bubbleless aeration, the inner side of the membrane is an aerobic environment, and the outer side is an anaerobic environment. During the residence time of 2 to 4 hours, ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) can fully oxidize ammonia nitrogen into nitrite and nitrate. At the same time, denitrifying bacteria under anaerobic conditions use organic carbon sources to reduce part of the nitrate to nitrogen gas. This residence time ensures that nitrification and denitrification processes are carried out simultaneously on the surface of the MABR membrane and in the liquid phase, realizing simultaneous nitrification and denitrification (SND). In this way, nitrogen pollutants in sewage can be effectively removed in the same reaction unit, the denitrification effect of the system is improved, and the energy consumption demand in the aerobic stage is reduced.

[0115] Furthermore, in the deoxygenation treatment stage, the hydraulic retention time is controlled to 1~3 hours, which can make full use of the residual organic matter in the sewage for denitrification reaction. The role of deoxygenation treatment is to further remove nitrates and nitrites in the water after MABR treatment, thereby achieving nitrogen removal. In the deoxygenation zone, the dissolved oxygen content is very low, which is suitable for the growth of heterotrophic denitrifying bacteria. These bacteria use the residual organic matter in the water as electron donors to convert nitrates and nitrites into nitrogen gas. Controlling the hydraulic retention time to 1~3 hours can ensure that the denitrifying bacteria have enough time to complete the denitrification reaction and improve the removal rate of nitrates. If the retention time is too short, the denitrification process may not be fully carried out, resulting in an excessive concentration of total nitrogen in the effluent. However, too long a retention time will increase the volume and operating costs of the tank body, so a 1~3 hour HRT can ensure the best balance between denitrification effect and economy.

[0116] In the first aerobic treatment stage, the hydraulic retention time is controlled to be 1~2 hours, which can effectively remove the remaining ammonia nitrogen and some refractory organic matter in the water. In the aerobic zone, sufficient dissolved oxygen is provided by aeration to ensure the activity of aerobic microorganisms. During the 1~2 hour retention time, microorganisms can use oxygen to further oxidize the residual ammonia nitrogen in the sewage into nitrates, while promoting the degradation of organic pollutants. Another important function of the aerobic zone is to encourage polyphosphate bacteria to absorb phosphates in the water and store them in the form of polyphosphates in the cells. Shorter HRT also helps to enhance the flocculation of sludge particles through appropriate aeration, forming large and compact sludge flocs to improve the mud-water separation effect. The 1~2 hour retention time can not only ensure the full metabolism of aerobic microorganisms, but also prevent high energy consumption caused by excessive aeration, thereby achieving economical and efficient sewage treatment.

[0117] In order to make the sewage treatment method provided by the present invention have better effluent water quality, the flow ratio of the part of the sludge obtained by the sedimentation treatment for anaerobic treatment to the feed sewage can be controlled to be 0.8-1.2, that is, the sludge return ratio is 80%-120%. This return ratio can ensure that sufficient activated sludge concentration is maintained in the system to support the effective degradation reaction of microorganisms. This ratio helps to improve the removal rate of organic matter and nitrogen, enhance the stability and treatment effect of the system, and reduce the difficulty of sludge sedimentation and maintain the treatment efficiency.

[0118] In one embodiment, in the sewage treatment method provided by the present invention, MABR treatment is performed using a MABR membrane module. The method further includes obtaining the oxygen content in the gas entering and leaving the MABR membrane module, calculating the MABR oxygen transfer efficiency using Formula 1 and Formula 2, and calculating the gas supply per unit membrane area of ​​the MABR membrane module using Formula 3 based on the MABR oxygen transfer efficiency;

[0119] Formula 1;

[0120] Formula 2;

[0121] Formula 3;

[0122] OTE: MABR oxygen transfer efficiency;

[0123] : The oxygen content in the gas entering the MABR membrane module;

[0124] : Gas volume loss coefficient;

[0125] : The oxygen content in the gas leaving the MABR membrane module;

[0126] : Gas supply per unit membrane area of ​​MABR membrane module, Nm 3 / m 2 / h.

[0127] The gas entering the MABR membrane module can be air or oxygen. When air is used as the gas source for the MABR membrane module, The fixed value can be 20.9%. In the present invention, the oxygen content refers to the volume fraction of oxygen in the mixed gas.

[0128] Ammonia nitrogen removal in traditional sewage treatment plants is achieved through aeration in aerobic tanks. Automatic control of aeration volume is achieved through ammonia nitrogen-based aeration control via feedforward or feedback. This aeration method has relatively low accuracy and is prone to problems such as excessive aeration and substandard effluent ammonia nitrogen. At the same time, with the in-depth study of MABR, due to its high oxygen mass transfer efficiency, it has received increasing attention in ammonia oxidation and simultaneous nitrification and denitrification.

[0129] The air supply of the MABR unit also determines the effect of denitrification. If the air supply is too large, it will lead to energy waste and affect the anoxic environment of the MABR unit, which will affect the denitrification effect. If the air supply is too small, it will be difficult to gather nitrifying bacteria on the surface of the MABR membrane. At the same time, after long-term operation, the surface of the MABR membrane will not have enough oxygen, which will lead to the growth of heterotrophic bacteria, making it impossible for MABR to play its advantages. Too large an internal reflow ratio will cause the system to change from plug flow to complete mixing, resulting in poor sludge properties.

[0130] The inventors found that the oxygen content in the gas (tail gas) leaving the MABR pool is related to the ammonia nitrogen concentration of the inlet water. The higher the ammonia nitrogen concentration, the lower the oxygen content of the tail gas; the lower the ammonia nitrogen concentration, the higher the oxygen content of the tail gas. The oxygen content of the tail gas determines the amount of gas supplied by the MABR unit. Therefore, the present invention also establishes a relationship between the MABR gas supply and the oxygen content in the tail gas, which can achieve accurate gas supply in the MABR pool, while improving the treatment effect and reducing production costs.

[0131] In one embodiment, the sewage treatment method provided by the present invention further includes sequentially performing a first deoxygenation treatment, a first aerobic treatment, a second deoxygenation treatment, and a second aerobic treatment on the MABR effluent to obtain deoxygenation-aerobic treatment effluent; and further includes performing a second deoxygenation treatment on at least part of the feed sewage, and then performing a sedimentation treatment on the second aerobic treatment effluent. The above process is to perform two deoxygenation-aerobic treatments on the MABR treated effluent, the first deoxygenation-aerobic treatment includes the first deoxygenation treatment and the first aerobic treatment, and the second deoxygenation-aerobic treatment includes the second deoxygenation treatment and the second aerobic treatment.

[0132] The second deoxygenation treatment and the second aerobic treatment are treatment processes that are placed after the first aerobic treatment. The treatment parameters can be the same as those of the first deoxygenation treatment, or the parameters commonly used in the art can be used. The second deoxygenation treatment can further improve the effluent quality. The second deoxygenation treatment of at least part of the feed wastewater can supplement the carbon source for the nitrate nitrogen in the first aerobic effluent, which is beneficial to further denitrification and reduces the impact of fluctuations in the influent water volume and quality on the system.

[0133] Furthermore, part of the feed sewage can be used as the second influent to directly undergo the second deoxidation treatment. The carbon source in the second influent can provide an electron donor for the nitrate nitrogen in the first aerobic effluent, reducing the dependence of the denitrification process on external carbon source agents. When the feed sewage undergoes anaerobically treatment and the second deoxidation treatment at the same time, the volume ratio of the feed sewage undergoing anaerobic treatment and the second deoxidation treatment is 3:(1~2), which can achieve the technical effects of reducing the reflux ratio of nitrification liquid, reducing dependence on external carbon source agents, and improving the impact resistance of the system. Furthermore, at least part of the effluent from the second aerobic treatment can be refluxed for the first deoxidation treatment. At this time, the effluent from the first aerobic treatment is no longer refluxed for the first deoxidation treatment.

[0134] The second aspect of the present invention provides an AMAO sewage treatment system. The system includes an anaerobic tank, a MABR tank, at least one anaerobic-aerobic unit, and a sedimentation tank;

[0135] The deoxidation-aerobic unit comprises a deoxidation tank and an aerobic tank which are connected in sequence;

[0136] The outlet of the anaerobic tank is connected to the inlet of the MABR tank;

[0137] The outlet of the MABR tank is connected to the inlet of the aerobic-aerobic unit;

[0138] The outlet of the oxygen-dissolving-aerobic unit at the end is respectively connected with the inlet of the sedimentation tank and the inlet of the oxygen-dissolving-aerobic unit at the head end;

[0139] The MABR tank includes a MABR membrane module;

[0140] The sludge outlet of the sedimentation tank is connected with the sludge inlet of the anaerobic tank.

[0141] Specifically, the anaerobic tank is used to perform anaerobic treatment; the MABR tank is used to perform MABR treatment; the aerobic-aerobic unit includes an aerobic tank and an aerobic tank connected in sequence, wherein the aerobic tank is used to perform aerobic treatment and the aerobic tank is used to perform aerobic treatment; the sedimentation tank is used to perform sedimentation treatment. The MABR tank includes a MABR membrane module, and the sludge outlet of the sedimentation tank is connected to the sludge inlet of the anaerobic tank, so that at least part of the sludge obtained from the sedimentation treatment can be returned to the anaerobic tank for anaerobic treatment.

[0142] The present invention does not limit the number of aerobic-oxidative units, which can be selected according to demand. For example, in one embodiment, the AMAO sewage treatment system provided by the present invention includes one aerobic-oxidative unit.

[0143] For example, when the system includes only one aerobic-oxidative unit, the outlet of the aerobic-oxidative unit at the end is the outlet of the aerobic tank, and the inlet of the aerobic-oxidative unit at the head end is the inlet of the aerobic tank.

[0144] For another example, when the system includes two deoxidation-aerobic units, the outlet of the deoxidation-aerobic unit at the end is the outlet of the last aerobic pool passed along the direction of water flow, and the inlet of the deoxidation-aerobic unit at the head end is the inlet of the deoxidation pool, that is, the inlet of the first deoxidation pool passed along the direction of water flow.

[0145] Figure 1 The first AMAO sewage treatment system provided by the present invention is as follows Figure 1 As shown, the system includes 100-anaerobic tank, 200-MABR tank, 300-first deoxidation tank, 400-first aerobic tank, and 500-sedimentation tank. Among them, the outlet of 100-anaerobic tank is connected with the inlet of 200-MABR tank, the outlet of 200-MABR tank is connected with the inlet of 300-first deoxidation tank, the outlet of 300-first deoxidation tank is connected with the inlet of 400-first aerobic tank, the outlet of 400-first aerobic tank, i.e., the outlet of the deoxidation-aerobic unit at the end, is respectively connected with the inlet of 500-sedimentation tank and the inlet of 300-first deoxidation tank (the inlet of the deoxidation-aerobic unit at the head end); the sludge outlet of 500-sedimentation tank is connected with the sludge inlet of 100-anaerobic tank.

[0146] Among them, the outlet of the 400-first aerobic pool is connected to the inlet of the 300-first deoxidation pool, so that part of the effluent from the first aerobic treatment can be returned to the 300-first deoxidation pool for the first deoxidation treatment. The return of the effluent from the first aerobic treatment for the first deoxidation treatment can further utilize the COD in the effluent from the MABR treatment for denitrification; on the other hand, the ammonia nitrogen concentration in the effluent from the first aerobic treatment is very low, and the return to the rear end of the 200-MABR pool will not dilute the ammonia nitrogen concentration in the influent, which is beneficial for the 200-MABR pool to maintain a higher influent ammonia nitrogen load, so that it can cultivate more abundant AOB and NOB bacteria, and improve the autotrophic-heterotrophic synergistic denitrification effect of the MABR treatment.

[0147] The AMAO sewage treatment method provided by the present invention gives full play to the advantages of MABR, can achieve partial ammonia nitrogen removal in the 200-MABR pool, and fully utilizes the organic carbon source in the influent to achieve simultaneous nitrification and denitrification, without relying on the addition of external carbon source agents, thereby improving the denitrification effect of the system and making the effluent water quality better; at the same time, the present invention provides an operating parameter of the gas supply per unit membrane area of ​​MABR, which can avoid the problem of excessive or insufficient gas supply of MABR; and the present invention fully combines the advantages and characteristics of MABR and activated sludge process, provides conditions such as reflux mode and reflux amount, and can achieve complete coupling of the system; at the same time, utilizing the advantages of high oxygen mass transfer efficiency of MABR, simultaneous nitrification and denitrification are achieved in the 200-MABR pool, and the method can fully utilize the organic carbon source in the influent, reduce the dependence on external carbon sources, and reduce the ammonia nitrogen concentration entering the aerobic pool, so it can also greatly save the volume and aeration volume of the aerobic pool and reduce the operating energy consumption.

[0148] Furthermore, it also includes controlling the scrubbing frequency of the 200-MABR pool to 15~30s / h and the scrubbing gas volume to 3~8Nm 3 / h. On the one hand, the above scrubbing conditions can prevent the MABR membrane assembly from forming too thick biofilm, which will lead to excessive growth of heterotrophic bacteria and affect the oxygen mass transfer efficiency; on the other hand, they can increase the shear rate of the MABR membrane assembly and the contact frequency between ammonia nitrogen and the biofilm on the MABR surface.

[0149] In one embodiment, the effective volume ratio of 100-anaerobic tank, 200-MABR tank, 300-first oxygen elimination tank and 400-first aerobic tank can be controlled to be 1:(2~4):(2~3):(1~2). Different treatment structures have a suitable effective volume ratio to achieve efficient removal of different pollutants. This ratio ensures that each treatment unit has sufficient residence time to optimize the reaction processes such as anaerobic phosphorus release, nitrification and denitrification, nitrogen and phosphorus removal, improve the treatment effect and system stability, and reduce the floor space and operating costs.

[0150] In order to make the AMAO sewage treatment system provided by the present invention have better effluent water quality, in one embodiment, the dissolved oxygen concentration of the 100-anaerobic tank can be controlled to be 0-0.2 mg / L, and the dissolved oxygen of the 200-MABR tank can be controlled to be 0.2-0.5 mg / L; further, the filling area of ​​the MABR membrane module can be controlled to be 6-15 m according to the system treatment water volume. 2 / m 3 Feed sewage, and control the scrubbing intensity of MABR membrane components to 15~30s / h, scrubbing gas volume to 3~8Nm 3 / h. The above characteristics ensure that there is sufficient biofilm surface area for oxygen mass transfer and pollutant degradation, improve the denitrification efficiency and stability of the system, and ensure that pollutants are effectively removed.

[0151] In addition, the dissolved oxygen in the 400-first aerobic pool can be controlled to 1.5~2.5mg / L. The above dissolved oxygen concentration can prevent the 400-first aerobic pool from being over-aerated, which will cause the sludge microorganisms to loosen and affect the sedimentation effect at the back end, while reducing aeration energy consumption. At the same time, the sedimentation time of the 500-sedimentation pool can be controlled to 0.8~2.0h, and the surface hydraulic load to 0.4~1.0m 3 / (m 2 h) to achieve better processing effect.

[0152] In one embodiment, the 200-MABR pool is also provided with an oxygen concentration sensor, which can obtain the oxygen content in the gas entering and leaving the 200-MABR pool, respectively, so as to calculate the oxygen transfer efficiency of the 200-MABR pool using the content recorded above, and then determine the gas supply per unit membrane area of ​​the 200-MABR pool.

[0153] Figure 2 The second AMAO sewage treatment system provided by the present invention is as follows: Figure 2 As shown, the AMAO sewage treatment system provided by the present invention also includes 100-anaerobic tank, 200-MABR tank, 300-first oxygen elimination tank, 400-first aerobic tank, 600-second oxygen elimination tank, 700-second aerobic tank, 500-sedimentation tank; the outlet of 100-anaerobic tank is connected to the inlet of 200-MABR tank; the outlet of 200-MABR tank is connected to the inlet of 300-first oxygen elimination tank;

[0154] The outlet of the 300-first deoxidation tank is connected to the inlet of the 400-first aerobic tank; the outlet of the 400-first aerobic tank is connected to the inlet of the 600-second deoxidation tank; the outlet of the 600-second deoxidation tank is connected to the inlet of the 700-second aerobic tank; the outlet of the 700-second aerobic tank is connected to the inlet of the 300-first deoxidation tank and the inlet of the 500-sedimentation tank respectively. The 600-second deoxidation tank and the 700-second aerobic tank are used to perform the second deoxidation treatment and the second aerobic treatment respectively. The 600-second deoxidation tank receives the effluent from the 400-first aerobic tank, and after the second deoxidation treatment and the second aerobic treatment are performed in sequence, the outlet of the 700-second aerobic tank is connected to the inlet of the 500-sedimentation tank, so that the effluent of the second aerobic treatment is subjected to sedimentation treatment. In addition, part of the effluent from the 700-second aerobic tank can also flow back into the 300-first deoxidation tank, and the volume of this part of the return water is 0-100% of the system feed sewage volume.

[0155] When the AMAO sewage treatment system provided by the present invention also includes the interconnected 600-second oxygen elimination tank and 700-second aerobic tank, the feed sewage enters the system through the inlet of the 100-anaerobic tank and the inlet of the 600-second oxygen elimination tank at the same time, which can increase the carbon source and improve the effluent water quality.

[0156] Hereinafter, the AMAO wastewater treatment method provided by the present invention is described in detail using specific examples.

[0157] Example:

[0158] This embodiment uses Figure 1The AMAO wastewater treatment system shown treats the feed wastewater. The effective volume ratio of 100-anaerobic tank, 200-MABR tank, 300-first oxygen elimination tank and 400-first aerobic tank is 1: 2.5:1.5:1.

[0159] The water source comes from a municipal sewage treatment plant in Jiangsu Province. The water quality of the system inlet and outlet water is shown in Table 1.

[0160] Table 1

[0161]

[0162] The hydraulic retention time of the 100-anaerobic tank is 1.5 h, the redox potential of the treatment system in the 100-anaerobic tank is -280 mV, and the dissolved oxygen concentration of the treatment system in the 100-anaerobic tank is 0.1 mg / L.

[0163] The hydraulic retention time of the 200-MABR pool is 3.75h, the redox potential of the treatment system in the 200-MABR pool is -80mV, and the dissolved oxygen concentration of the treatment system in the 200-MABR pool is 0.45mg / L.

[0164] The 200-MABR pool includes a MABR membrane assembly, and the MABR membrane included in the MABR membrane assembly is a hollow fiber membrane with a filling area of ​​8m 2 / ton of water. The scrubbing intensity of a 200-MABR pool is 25s / h and the scrubbing gas volume is 6Nm 3 / h.

[0165] 300-The hydraulic retention time of the first deoxidation tank is 3h, 300-The redox potential of the treatment system in the first deoxidation tank is -50mV, 300-The dissolved oxygen concentration of the treatment system in the first deoxidation tank is 0.4mg / L.

[0166] 400-The hydraulic retention time of the first aerobic pool is 2h, 400-The redox potential of the treatment system in the first aerobic pool is 180mV, 400-The dissolved oxygen concentration of the treatment system in the first aerobic pool is 2.0mg / L.

[0167] 500- The sedimentation time of the sedimentation tank is 1h, and the surface hydraulic load is 0.8m 3 / (m 2 h).

[0168] The return ratio of 500-sedimentation tank backflow to 100-anaerobic tank (external return) is 100%; the return ratio is the ratio of the sludge flow from 500-sedimentation tank backflow to 100-anaerobic tank to the influent flow of AMAO sewage treatment system;

[0169] The reflux ratio from 400-the first aerobic pool to 300-the first deoxidation pool (internal reflux) is 120%; the reflux ratio is the ratio of the flow from 400-the first aerobic pool to 300-the first deoxidation pool to the inlet flow of the AMAO sewage treatment system.

[0170] This embodiment also includes the following contents:

[0171] The 200-MABR pool is equipped with oxygen concentration sensors, which are used to obtain the oxygen content in the gas entering and leaving the MABR membrane assembly. At a certain time point in the sampling interval, the oxygen concentration sensor detected that the oxygen content in the gas entering the MABR membrane assembly was 20.9%, and the oxygen content in the gas leaving the MABR membrane assembly was 14.8%. The gas volume loss coefficient was calculated to be 92.8% using Formula 2. Subsequently, the MABR oxygen transfer efficiency (OTE) was calculated to be 34.26% using Formula 1, and the gas supply per unit membrane area of ​​the MABR membrane assembly was calculated to be 0.00516Nm 3 / m 2 / h.

[0172] Comparative Example:

[0173] This comparative example uses Figure 3 The sewage treatment system shown treats the same feed sewage as in the example. The difference between this system and the system used in the example is that it does not include a 200-MABR tank, and the other structural operating parameters remain the same.

[0174] Test example:

[0175] 1. Detect the total nitrogen concentration of the feed sewage and product water to obtain the total nitrogen removal of the AMAO sewage treatment system in the embodiment (in g / h), and then detect the total nitrogen concentration in the sewage entering and leaving the 200-MABR pool to obtain the total nitrogen removal of the 200-MABR pool (in g / h). Divide the total nitrogen removal of the 200-MABR pool by the total nitrogen removal of the AMAO sewage treatment system to calculate the nitrogen removal percentage of MABR. The total nitrogen removal of the 200-MABR pool, the total nitrogen removal of the AMAO sewage treatment system, and the nitrogen removal percentage of MABR are shown in Figure 4 .

[0176] Depend on Figure 4 It can be seen that the percentage of nitrogen removal by MABR ranges from 1.4% to 39.5%, which indicates that the 200-MABR pool can play a role in removing total nitrogen from sewage.

[0177] 2. The ammonia nitrogen concentration of the influent entering the 200-MABR pool and the oxygen content in the gas leaving the 200-MABR pool were statistically analyzed to form a scatter plot, and the scatter plot data were fitted into a linear regression equation, see Figure 5 .Depend on Figure 5 It can be seen that the oxygen content in the gas leaving the 200-MABR pool is negatively correlated with the ammonia nitrogen concentration of the 200-MABR pool inlet water. The higher the ammonia nitrogen concentration, the lower the oxygen content.

[0178] With respect to the prior art, the present invention mainly improves as follows:

[0179] 1. Compared with the prior art, the AMAO sewage treatment system provided by the present invention has a short biochemical retention time and a small surface load of the 500- sedimentation tank, which greatly shortens the area occupied by the sewage treatment process.

[0180] 2. The AMAO sewage treatment system provided by the present invention is composed of an anaerobic tank, a MABR tank, an oxygen elimination tank, an aerobic tank, and a sedimentation tank. Among them, the reflux ratio of the external reflux is 80%~100%, and the reflux ratio of the internal reflux is 0~100%. Compared with the existing technology, the reflux ratio and reflux energy consumption are greatly shortened (the external reflux ratio of the traditional sewage treatment process is 100%~200%, and the internal reflux ratio is 200%~400%).

[0181] 3. In the AMAO sewage treatment system provided by the present invention, the internal reflow water inlet point is the end of the MABR pool or the front end of the deoxidation pool. The water inlet position will not dilute the ammonia nitrogen load of the MABR unit inlet water, which can further improve the simultaneous nitrification and denitrification performance of the MABR pool, reduce dependence on external carbon sources, and reduce the aeration amount of the aerobic pool. The dissolved oxygen in the aerobic pool can be between 1.5 and 2.5 mg / L (the dissolved oxygen in the traditional aerobic pool is 2 to 5 mg / L).

[0182] 4. By adjusting the internal and external reflow ratio and the scrubbing frequency and scrubbing gas volume of the MABR pool, the flocculent bacteria with capsules or mucus can be promoted to flocculate and integrate into floccules. The formed floccules have strong vitality, strong adsorption and oxidation capabilities, compact structure, strong regeneration ability, and improve the sludge settling performance of the system.

[0183] 5. The oxygen content of the tail gas of the MABR pool is related to the ammonia nitrogen concentration of the influent. The higher the ammonia nitrogen concentration, the lower the oxygen content of the tail gas; the lower the ammonia nitrogen concentration, the higher the oxygen content of the tail gas. The oxygen content of the tail gas determines the amount of gas supplied by the MABR unit. The relationship between the MABR gas supply and the oxygen content of the tail gas is established for the precise gas supply of the MABR unit.

[0184] 6. The AMAO sewage treatment system provided by the present invention adopts segmented water inlet, which can improve the system's anti-shock ability and cope with fluctuations in water quality and quantity on the one hand; on the other hand, it can flexibly adjust the water inlet ratio and classification level according to different water inlet concentrations.

[0185] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating AMAO sewage, characterized in that: The steps include: Anaerobic treatment is performed on the feed sewage to obtain anaerobic treatment effluent; Performing MABR treatment on the anaerobic treatment effluent to obtain MABR treated effluent; The MABR treated effluent is subjected to at least one deoxygenation-aerobic treatment to obtain deoxygenation-aerobic treated effluent; Performing sedimentation treatment on the effluent from the deoxidation-aerobic treatment to obtain product water; The deoxygenation-aerobic treatment includes deoxygenation treatment and aerobic treatment performed sequentially; Performing at least one oxygen-aerobic treatment on at least a portion of the oxygen-aerobic treatment effluent; Anaerobic treatment of at least part of the sludge obtained from the sedimentation treatment; The MABR treatment is carried out using a MABR membrane module; The MABR membrane assembly comprises a MABR membrane, wherein the MABR membrane is selected from at least one of a hollow fiber membrane, a plate membrane, a roll membrane, and a tubular membrane; The MABR treatment includes contacting the anaerobic treatment effluent with the MABR membrane assembly to obtain the MABR treatment effluent.

2. The AMAO sewage treatment method according to claim 1, characterized in that: In the anaerobic treatment, the redox potential of the treatment system is -300mV to -150mV; and / or, In the MABR treatment, the redox potential of the treatment system is -100mV~0mV; and / or, In the deoxidation treatment, the oxidation-reduction potential of the treatment system is -150mV to -50mV; and / or, In the aerobic treatment, the redox potential of the treatment system is 100mV~300mV.

3. The AMAO sewage treatment method according to claim 1, characterized in that: The hydraulic retention time of the MABR treatment is 2 to 4 hours; and / or, The hydraulic retention time of the deoxygenation treatment is 1 to 3 hours; and / or, The hydraulic retention time of the aerobic treatment is 1 to 2 hours; and / or, The flow ratio of at least part of the sludge to the feed sewage is 0.8-1.

2.

4. The AMAO sewage treatment method according to claim 1, characterized in that: The method also includes obtaining the oxygen content in the gas entering and leaving the MABR membrane assembly, calculating the MABR oxygen transfer efficiency using Formula 1 and Formula 2, and calculating the gas supply per unit membrane area of ​​the MABR membrane assembly using Formula 3 according to the MABR oxygen transfer efficiency; Formula 1; Formula 2; Formula 3; OTE: MABR oxygen transfer efficiency; : The oxygen content in the gas entering the MABR membrane module; : Gas volume loss coefficient; : The oxygen content in the gas leaving the MABR membrane module; : Gas supply per unit membrane area of ​​MABR membrane module, Nm 3 / m 2 / h.

5. The AMAO sewage treatment method according to any one of claims 1 to 4, characterized in that: The method comprises sequentially performing a first deoxygenation treatment, a first aerobic treatment, a second deoxygenation treatment, and a second aerobic treatment on the MABR effluent to obtain deoxygenation-aerobic treatment effluent; The method also includes subjecting at least a portion of the feed wastewater to a second deoxygenation treatment.

6. The AMAO sewage treatment method according to claim 5, characterized in that: The volume ratio of the feed sewage for the anaerobic treatment to the feed sewage for the second deoxidation treatment is 3:(1-2).

7. An AMAO sewage treatment system for executing the AMAO sewage treatment method according to any one of claims 1 to 6, characterized in that: Includes anaerobic tanks, MABR tanks, at least one anaerobic-aerobic unit, and sedimentation tanks; The deoxidation-aerobic unit comprises a deoxidation tank and an aerobic tank which are connected in sequence; The outlet of the anaerobic tank is connected to the inlet of the MABR tank; The outlet of the MABR tank is connected to the inlet of the oxic-aerobic unit; The outlet of the oxygen-dissipation-aerobic unit at the end is respectively connected to the inlet of the sedimentation tank and the inlet of the oxygen-dissipation-aerobic unit at the head end; The MABR tank includes a MABR membrane module; The sludge outlet of the sedimentation tank is communicated with the sludge inlet of the anaerobic tank.

8. The AMAO sewage treatment system according to claim 7, characterized in that: The dissolved oxygen concentration of the anaerobic tank is 0-0.2 mg / L, the dissolved oxygen concentration of the MABR tank is 0.2-0.5 mg / L, and the dissolved oxygen concentration of the aerobic tank is 1.5-2.5 mg / L; and / or, The filling area of ​​the MABR membrane module is 6~15m 2 / m 3 Feed sewage; The scrubbing intensity of the MABR membrane assembly is 15-30s / h, and the scrubbing gas volume is 3-8Nm 3 / h.

9. The AMAO sewage treatment system according to claim 8, characterized in that: The MABR tank is also provided with an oxygen concentration sensor for respectively obtaining the oxygen content in the gas entering and leaving the MABR membrane module.

10. The AMAO sewage treatment system according to claim 9, characterized in that: Including anaerobic tank, MABR tank, first oxygen elimination tank, first aerobic tank, second oxygen elimination tank, second aerobic tank, sedimentation tank; The outlet of the anaerobic tank is connected to the inlet of the MABR tank; The outlet of the MABR tank is connected to the inlet of the first oxygen elimination tank; The outlet of the first oxygen elimination tank is connected to the inlet of the first aerobic tank; The outlet of the first aerobic tank is connected to the inlet of the second oxygen elimination tank; The outlet of the second oxygen elimination tank is connected to the inlet of the second aerobic tank; The outlet of the second aerobic tank is communicated with the inlet of the first oxygen elimination tank and the inlet of the sedimentation tank respectively.

Images