Efficient processing method based on MBBR (moving bed biofilm reactor)

Abstract

The invention discloses an efficient treatment method based on an MBBR (Moving Bed Biofilm Reactor), and relates to the technical field of sewage treatment. The required treatment system comprises a first MBBR reaction tank, a second MBBR reaction tank and a solid-liquid separation tank, a first suspended carrier and a second suspended carrier are added into the first MBBR reaction tank and the second MBBR reaction tank respectively, and a first micro-nano aerator and a second micro-nano aerator are arranged at the bottoms of the first MBBR reaction tank and the second MBBR reaction tank respectively. The specific surface area of micro-nano bubbles formed by the first micro-nano aerator and the second micro-nano aerator is large, the contact area of gas and water is greatly increased, the surface of the micro-nano bubbles is charged, the micro-nano bubbles can react with other pollutants in sewage to be treated, the purification efficiency is improved, meanwhile, the micro-nano bubbles can drive SS to rise in the rising process, and the purification effect is improved. And solid-liquid separation is realized. According to the invention, the aeration performance is improved, and synchronous removal of organic matters, ammonia nitrogen and SS is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to an efficient treatment method based on MBBR. Background Art

[0002] The oxygen-consuming pollutants in sewage are mainly organic matter and ammonia nitrogen. Air needs to be blown into the sewage to remove pollutants through aerobic microbial decomposition. During the operation of sewage treatment plants, 50% to 60% of the energy consumption is used for aeration. Although aeration reduces the concentration of oxygen-consuming pollutants in water, it also indirectly leads to an increase in operating costs and carbon emissions. Therefore, the key to achieving carbon reduction and economic operation is to reduce air volume, and further to increase oxygen utilization.

[0003] The research reports on MBBR efficient treatment in the prior art include:

[0004] Application No. 202310010886.7 discloses a high-salt wastewater treatment method based on the MBBR process, which first adds inoculated biologically activated sludge into the MBBR reactor to form a preliminary biofilm, and controls the microbial growth environment in the MBBR reactor by appropriate aeration and sludge return. After the biologically activated sludge initially forms a biofilm on the surface of the suspended filler, a quantitatively screened halophilic microbial agent is added to the MBBR reactor to accelerate the dominance of the biofilm-forming microbial flora, so that the dominant flora penetrates the interior of the filler and adheres to the surface of the filler, and finally grows a biofilm inside and outside the filler. Application No. 202320480662.8 discloses an MBBR process integrated treatment equipment, including an anaerobic tank, a first variable reaction tank, a second variable reaction tank, a third variable reaction tank and a membrane tank. Adjacent tanks are connected through water holes in the tank wall. An anaerobic tank stirring device is provided inside the anaerobic tank. The three variable reaction tanks are all provided with a reaction tank stirring device, an MBBR stuffing box cage and an aeration device, wherein the aeration devices are all arranged at the bottom of the reaction tank and are all connected to the first fan outside the reaction tank; an MBR membrane assembly is provided in the membrane tank, the bottom aeration system of the MBR membrane assembly is connected to the second fan outside the membrane tank, and an outlet is provided on the top of the MBR membrane assembly; the bottom outlets of the second variable reaction tank and the third variable reaction tank are connected to the bottom outlet of the first variable reaction tank through a nitrification liquid reflux pump; the bottom outlet of the membrane tank is connected to the anaerobic tank through a sludge reflux pump.

[0005] In the above-mentioned prior art, aeration devices are used in the process of water treatment using MBBR technology, but the traditional aeration method is mainly microporous aeration or perforated tube aeration, the effective specific surface area of ​​the bubbles is small, and the rising flow rate is fast, resulting in low utilization rate. The bubbles rise vertically and escape directly into the atmosphere, which also causes ineffective utilization of the bubbles. Therefore, improving the utilization rate of aeration oxygen and further improving the utilization rate of aeration bubbles can not only improve the pollution removal performance of the biochemical system and reduce the electricity consumption of the sewage treatment plant, but also improve the operating efficiency of the sewage treatment plant and achieve multi-target pollution removal. It is an inevitable process for the sewage treatment plant to achieve green and low-carbon transformation.

[0006] This shows that the prior art needs to be further improved. Summary of the invention

[0007] The object of the present invention is to provide an efficient treatment method based on MBBR, which introduces micro-nano aeration into the treatment method. The gas oxygen utilization rate generated by the micro-nano aeration is high, the aeration performance is improved, and the synchronous removal of organic matter, ammonia nitrogen and SS is achieved.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] An efficient treatment method based on MBBR comprises the following steps:

[0010] a. Prepare and install the required processing system

[0011] The treatment system comprises a first MBBR reaction tank, a second MBBR reaction tank and a solid-liquid separation tank, wherein a first suspension carrier and a second suspension carrier are respectively added into the first MBBR reaction tank and the second MBBR reaction tank, a first micro-nano aerator and a second micro-nano aerator are respectively arranged at the bottom of the first MBBR reaction tank and the second MBBR reaction tank, the first micro-nano aerator is connected to a first micro-nano bubble generator, the second micro-nano aerator is connected to a second micro-nano bubble generator, and a stirrer is arranged in the first MBBR reaction tank and the second MBBR reaction tank;

[0012] A bottom intercepting screen is provided between the first suspension carrier and the first micro-nano aerator, and between the second suspension carrier and the second micro-nano aerator;

[0013] The wastewater to be treated enters from the first MBBR reaction tank and flows out from the solid-liquid separation tank;

[0014] The solid-liquid separation tank comprises a tank body, and a mud bucket, a mud collecting tank and a mud scraper located in the tank body. The mud collecting tank is provided with a mud discharge pipe and a mud return pipeline, and the mud bucket is connected with the mud discharge pipe; the mud discharge pipe of the mud collecting tank and the mud return pipeline are respectively provided with a first control valve and a second control valve;

[0015] The pore size of the first micro-nano aerator is 10-100 nm, and the pore size of the second micro-nano aerator is 10-20 μm;

[0016] b. The sewage to be treated enters the first MBBR reaction tank, the agitator is turned on, the influent SS is lower than 50 mg / L, and micro-nano bubbles are provided to the first MBBR reaction tank and the second MBBR reaction tank through the first micro-nano aerator and the second micro-nano aerator respectively;

[0017] c. Run:

[0018] Normal operation state: close the second control valve, open the first control valve, and control the power density of the first MBBR reaction pool to 7-12W / m 3 The power density of the second MBBR reaction tank is 7-12W / m 3 , the aeration volume of the first MBBR reaction tank is 70% to 80% of the total aeration volume;

[0019] Strong hydraulic shear stage I: close the second control valve, open the first control valve, and control the power density of the first MBBR reaction tank to 15-20W / m 3 The power density of the second MBBR reaction tank is 7-12W / m 3 The first MBBR reaction tank supplies oxygen according to the removal demand of oxygen-consuming pollutants, and the second MBBR reaction tank supplies oxygen at 1.1 to 1.3 times the removal demand of oxygen-consuming pollutants;

[0020] Strong hydraulic shear stage II: close the second control valve, open the first control valve, and control the power density of the first MBBR reaction tank to 7-12W / m 3 The power density of the second MBBR reaction tank is 12-15W / m 3 The first MBBR reaction tank supplies oxygen according to 1.1 to 1.2 times the removal demand of oxygen-consuming pollutants, and the second MBBR reaction tank supplies oxygen according to the removal demand of oxygen-consuming pollutants.

[0021] In the above-mentioned MBBR-based efficient treatment method, in step c, for the MBBR reaction pool with the core of removing organic matter, the strong hydraulic shear stage I is started once every 10 to 15 days, and each time it is started for 2 to 3 hours; the hydraulic shear stage II is started once every 20 to 25 days, and each time it is started for 1.5 to 2.0 hours; for the MBBR reaction pool with the core of removing ammonia nitrogen, the strong hydraulic shear stage I is started once every 20 to 25 days, and each time it is started for 1 to 2 hours, and the hydraulic shear stage II is started once every 35 to 40 days, and each time it is started for 1 to 1.5 hours;

[0022] When the residence time of oxygen-consuming pollutants in the inlet water exceeds 1.3 times the design value for three consecutive times, the second control valve is opened and the first control valve is closed. When the residence time of oxygen-consuming pollutants in the inlet water is lower than 1.1 times the design value for three consecutive times, the second control valve is closed and the first control valve is opened.

[0023] In the above-mentioned MBBR-based efficient treatment method, the mud bucket and the mud collecting trough are respectively located at the bottom and the top of the pool body, and the mud scraper rotates clockwise.

[0024] In the above-mentioned MBBR-based efficient treatment method, the volume of the first MBBR reaction pool accounts for 60% to 70% of the total reaction pool volume, and removes 80% to 90% of oxygen-consuming pollutants in the influent.

[0025] In the above-mentioned MBBR-based efficient treatment method, the power density of the agitator of the first MBBR reaction tank is 7-20 W / m 3 The power density of the agitator in the second MBBR reaction tank is 7-15W / m 3 .

[0026] In the above-mentioned MBBR-based efficient treatment method, the specific gravity of the first suspended carrier is 1.05-1.10 g / cm 3 The specific gravity of the second suspension carrier is 1.15-1.20 g / cm 3 The first suspension carrier and the second suspension carrier are both cylindrical carriers with a thickness of 3 to 5 mm and a pore size of 4 to 5 mm.

[0027] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0028] (1) The present invention proposes an efficient treatment method based on MBBR, which divides the total reaction pool into a first MBBR reaction pool and a second MBBR reaction pool, and respectively arranges a first micro-nano aerator and a second micro-nano aerator at the bottom of each reaction pool. The nano bubbles formed by the micro-nano aerator have a large specific surface area, which greatly increases the contact area between gas and water; and the surface of the micro-nano bubbles is charged, which helps to react with other pollutants in the sewage to be treated, thereby improving the purification efficiency; in addition, the micro-nano bubbles are not easy to rise in the water, and can stay in the water for a long time to continuously provide oxygen.

[0029] (2) Efficient utilization of aeration: Micro-nano aerators supply air, which is used for aerobic biochemical processes. The unused micro-nano bubbles drive SS to float during the further rise process, realizing the synchronous solid-liquid separation process and improving the utilization rate of bubbles.

[0030] (3) Flexible operation control and stable effect. The present invention effectively avoids the problem of biofilm thickening under efficient mass transfer by controlling the fluidization dynamics of the first MBBR reaction tank and the second MBBR reaction tank and controlling and alternating the gas supply volume, thereby ensuring the stable mass transfer and oxygen transfer process of the system and ensuring that the water quality of the total effluent during the backwashing process meets the established standards.

[0031] (4) Save aeration volume, save energy and reduce consumption. Micro-nano aeration gas has high oxygen utilization rate and low gas consumption. For municipal sewage treatment, it can save 80% of aeration volume and more than 50% of biochemical energy consumption. At the same time, through the control of key equipment such as suspended carriers, the long-term stable mass transfer and oxygen transfer process of the system is guaranteed, and the stable operation of the system is achieved.

[0032] (5) The simultaneous removal of organic matter, ammonia nitrogen and SS is achieved. The advantages of high EPS content in the detached biofilm are fully utilized, the biological flocculation function is utilized, and accompanied by micro-nano bubbles, the solid-liquid separation is achieved, and the addition of chemical agents is reduced.

[0033] (6) High pollution removal efficiency and land saving. Compared with conventional aeration methods in the prior art, the effective specific surface area of ​​micro-nano bubbles is increased, the gas-liquid contact area is increased, the mass transfer effect is good, and the biofilm treatment load is significantly improved. Compared with the traditional activated sludge method, the land area is reduced by 70%, and compared with the traditional MBBR, it is further reduced by 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below in conjunction with the accompanying drawings:

[0035] Figure 1 It is a simplified structural diagram of the processing system of the present invention;

[0036] In the figure: V1-first MBBR reaction tank; V2-second MBBR reaction tank; V3-solid-liquid separation tank; T1-first suspended carrier; T2-second suspended carrier; Q1-first micro-nano aerator; Q2-second micro-nano aerator; F1-first micro-nano bubble generator; F2-second micro-nano bubble generator; Z1-first control valve; Z2-second control valve; L1-sludge return pipeline; 1-outlet interception screen; 2-bottom interception screen; 3-mud collecting trough; 4-mud discharge pipe; 5-outlet pipe; 6-mud scraper; 7-mud bucket; 8-water inlet pipe. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0038] The technical concept of the present invention is: Moving Bed Biofilm Reactor (MBBR) has become one of the mainstream processes for sewage treatment in the new era due to its strong functional bacteria enrichment ability and high treatment efficiency. Oxygen transfer is the main limiting factor restricting the macroscopic effect of biofilm. Therefore, the advantages of small particle size and large effective specific surface area of ​​micro-nano bubbles are combined to improve the oxygen transfer process and treatment performance. However, the rising velocity of micro-nano bubbles is slow, and the unused micro-nano bubbles are retained in the water, which affects the solid-liquid separation of the back-end process. Therefore, graded aeration is adopted, and the bubble particle size is increased step by step to gradually increase the rising velocity of the bubbles, make full use of the micro-nano bubbles that are not consumed by the aerobic zone, and drive the light SS to separate upward through the rising process, so as to achieve solid-liquid separation and achieve the dual utilization effect of micro-nano bubbles.

[0039] It is understandable that the connection relationship described in this application refers to direct or indirect connection. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components. For example, A and C can be directly connected, and C and B can be directly connected, so that A and B are connected through C. It is also understandable that the "A connects B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0040] In the description of this application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this article is only a way to describe the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0041] In the description of this application, words such as "first" and "second" are only used to distinguish different objects, and do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0042] The technical solution of the present application is further described in detail below in conjunction with the accompanying drawings.

[0043] The "oxygen-consuming pollutants" mentioned in the present invention refer to the reducing pollutants in sewage, which are generally mainly organic matter and ammonia nitrogen.

[0044] like Figure 1As shown, the treatment system of the present invention includes a reaction tank, which is divided into a first MBBR reaction tank V1 and a second MBBR reaction tank V2. A solid-liquid separation tank V3 is arranged after the second MBBR reaction tank V2. Influent enters from the first MBBR reaction tank V1, flows into the second MBBR reaction tank V2, and is discharged from the second MBBR reaction tank V2 into the solid-liquid separation tank V3.

[0045] The first suspended carrier T1 and the second suspended carrier T2 are added to the first MBBR reaction tank and the second MBBR reaction tank, respectively. The first micro-nano aerator Q1 and the second micro-nano aerator Q2 are respectively arranged at the bottom of the first MBBR reaction tank and the second MBBR reaction tank. The first micro-nano aerator Q1 and the second micro-nano aerator Q2 have the same structure and can be operated using the existing technical structure and principle. The first micro-nano aerator is connected to the first micro-nano bubble generator F1, the second micro-nano aerator is connected to the second micro-nano bubble generator F2, and a stirrer is arranged in the first MBBR reaction tank and the second MBBR reaction tank.

[0046] A bottom intercepting screen 2 is arranged between the first suspension carrier and the first micro-nano aerator, and between the second suspension carrier and the second micro-nano aerator. A water outlet intercepting screen 1 is arranged at the water outlet of each reaction tank. The bottom intercepting screen 2 separates the first micro-nano aerator, the second micro-nano aerator and the suspension carriers located above them, that is, the first micro-nano aerator and the second micro-nano aerator supply air at the bottom of the reaction tank respectively, and micro-nano bubbles pass through the bottom intercepting screen 2 and enter the upper part.

[0047] The solid-liquid separation tank includes a tank body, and a mud hopper 7, a mud collecting tank 3 and a mud scraper 6 located in the tank body. The mud collecting tank 3 is provided with a mud discharge pipe 4 and a sludge return pipeline L1. The sludge return pipeline L1 is connected to the outlet pipe 5 on the solid-liquid separation tank and the inlet pipe 8 on the first MBBR reaction tank. The mud hopper 7 is connected to the mud discharge pipe; the first control valve Z1 and the second control valve Z2 are respectively provided on the mud discharge pipe and the sludge return pipeline.

[0048] The sludge collection in the solid-liquid separation tank is divided into the bottom and the upper part. The bottom collects particles with a large specific gravity, such as sand, which are inorganic and inactive; the upper part collects the detached biofilm, which still has high activity. By setting up a sludge return pipeline, when there is water quality shock in the influent, effective microorganisms can be returned to improve the system's treatment performance.

[0049] The aperture of the first micro-nano aerator is 10-100nm, and the aperture of the second micro-nano aerator is 10-20μm. The purpose of this setting is that the first MBBR reaction tank is micro-nano aeration, which is responsible for the removal of major pollutants, and the second MBBR reaction tank increases the aeration aperture, mainly to increase the gas rising flow rate, which is convenient for solid-liquid separation to produce flotation process.

[0050] Furthermore, the first MBBR reaction tank has a volume of 60% to 70% of the total volume of the MBBR reaction tank, and removes 80% to 90% of oxygen-consuming pollutants in the influent.

[0051] Furthermore, the power density of the agitator in the first MBBR reaction tank is 7-20 W / m 3 The power density of the agitator in the second MBBR reactor is 7-15W / m 3 .

[0052] Furthermore, the specific gravity of the first suspension carrier is 1.05-1.10 g / cm 3 The specific gravity of the second suspension carrier is 1.15-1.20 g / cm 3 The first suspension carrier and the second suspension carrier are both cylindrical carriers with a thickness of 3 to 5 mm and a pore size of 4 to 5 mm. Since the rising velocity of microbubbles in the second MBBR reaction tank is large, the specific gravity of the second suspension carrier is greater than that of the first suspension carrier.

[0053] The operation method of the above system is described below.

[0054] The specific steps include:

[0055] (1) Normal operation state: close the second control valve, open the first control valve, and control the power density of the first MBBR reaction tank to 7-12 W / m 3 The power density of the second MBBR reaction tank is 7-12W / m 3 The aeration volume of the first MBBR reaction tank is 70% to 80% of the total aeration volume, and the aeration volume of the second MBBR reaction tank is 10% to 20% of the total aeration volume.

[0056] (2) Strong hydraulic shear stage I: close the second control valve and open the first control valve to control the power density of the first MBBR reaction tank to 15-20 W / m 3 The power density of the second MBBR reaction tank is 7-12W / m 3 The first MBBR reaction tank supplies oxygen according to the removal demand of oxygen-consuming pollutants, and the second MBBR reaction tank supplies oxygen according to 1.1 to 1.3 times the removal demand of oxygen-consuming pollutants.

[0057] (3) Strong hydraulic shear stage II: close the second control valve and open the first control valve to control the power density of the first MBBR reaction tank to 7-12 W / m 3 The power density of the second MBBR reaction tank is 12-15W / m 3The first MBBR reaction tank supplies oxygen according to 1.1 to 1.2 times the removal demand of oxygen-consuming pollutants, and the second MBBR reaction tank supplies oxygen according to the removal demand of oxygen-consuming pollutants.

[0058] (4) For reactors whose core is to remove organic matter, strong hydraulic shear stage I is started once every 10 to 15 days, and each time it is started for 2 to 3 hours; hydraulic shear stage II is started once every 20 to 25 days, and each time it is started for 1.5 to 2.0 hours; for reactors whose core is to remove ammonia nitrogen, strong hydraulic shear stage I is started once every 20 to 25 days, and each time it is started for 1 to 2 hours; hydraulic shear stage II is started once every 35 to 40 days, and each time it is started for 1 to 1.5 hours.

[0059] (5) When the residence time of oxygen-consuming pollutants in the influent water exceeds 1.3 times the design value for three consecutive times, the second control valve is opened and the first control valve is closed. When the residence time of oxygen-consuming pollutants in the influent water is less than 1.1 times the design value for three consecutive times, the second control valve is closed and the first control valve is opened.

[0060] The present invention will be further described below in conjunction with specific embodiments:

[0061] Embodiment 1:

[0062] A pilot system verifies the operation effect of the whole system through the aerator setting. The test water is the effluent from the primary sedimentation tank of a sewage treatment plant in the north, with COD of 300-350 mg / L and ammonia nitrogen of 45-50 mg / L. The results of the aeration operation test with the addition of suspended carriers are shown in Table 1. As can be seen from Table 1, the first MBBR reaction tank and the second MBBR reaction tank use the same micro-nano aerator, and the biochemical tank operates well, with the effluent COD and ammonia nitrogen being lower than 30 mg / L and 1.5 mg / L respectively. However, after entering the solid-liquid separation tank, due to the low rising velocity of nanobubbles, they are suspended in the sewage for a long time, resulting in difficulty in solid-liquid separation, turbid effluent, and SS reaching 200 mg / L. The back end still needs to add a solid-liquid separation process. Therefore, from the perspective of increasing the rising velocity of bubbles and driving the microorganisms to float, the size of the second micro-nano aerator in the second MBBR reaction tank was adjusted to 1μm~10μm and 10μm~20μm respectively on the basis of the first micro-nano aerator in the first MBBR reaction tank remaining unchanged, forming aeration mode 2 and aeration mode 3. After increasing the bubble diameter, the rising velocity is improved. Intuitively, the effect of solid-liquid separation is getting better and better. Among them, after adopting aeration mode 3, the effluent SS can basically be reduced to 10mg / L, and no coagulant or coagulant aid is added during operation, making full use of the advantages of high extracellular polymers (EPS) of the detached biofilm and good biological flocculation effect, and realizing solid-liquid classification. However, after the size of the second micro-nano aerator in the second MBBR reaction tank was increased, in order to ensure that COD and ammonia nitrogen meet the standards, the aeration volume was also increased to a certain extent.

[0063] Table 1 Operation effect of the whole system under different aeration modes

[0064]

[0065] Embodiment 2:

[0066] On the basis of Example 1, the aeration volume of the second MBBR reaction tank was closed, and the effect of regulating the aeration volume of the first MBBR reaction tank on the nitrification effect of the overall system was studied. The test water was the influent of the aerobic pool of the biochemical section of a sewage plant in the north, with ammonia nitrogen of 45-50 mg / L. The treatment system of the present invention was adopted, and the first MBBR reaction tank accounted for 60% of the tank volume, and the first MBBR reaction tank and the second MBBR reaction tank were aerated and operated with suspended carriers. The characteristics of micro-nano bubbles are high effective specific surface area and long gas-liquid contact time. Therefore, in terms of experimental thinking, the effect of the first MBBR reaction tank should be fully utilized to ensure the removal of overall oxygen-consuming pollutants. The test results are shown in Table 2. It can be seen from Table 2 that under the given aeration volume, the first MBBR reaction tank can remove 64.29% of ammonia nitrogen. After further increasing the aeration ratio of the first MBBR reaction tank, the nitrification capacity of the first MBBR reaction tank is further improved. When the aeration volume exceeds 80%, the nitrification performance of the first MBBR reaction tank has basically reached the limit state, and the subsequent further improvement is of little significance, and a certain proportion still needs to be allocated to the second MBBR reaction tank. Therefore, in this case, when the first MBBR reaction tank capacity ratio is 60%, it is appropriate to give 70% to 80% aeration. At this time, about 80% of ammonia nitrogen can be removed, achieving the goal of reducing ammonia nitrogen load.

[0067] Table 2 Aeration rate operation effect of the first MBBR reactor

[0068] Ammonia nitrogen concentration 60% aeration 70% aeration 80% aeration 90% aeration Total water inlet 46.82 46.82 46.82 46.82 <![CDATA[Effluent of the first MBBR reaction tank / mg·L -1 > 16.72 12.13 10.29 9.58 <![CDATA[Effluent of the second MBBR reaction tank / mg·L -1 > 10.54 9.31 8.23 7.92 Nitrification ratio of the first MBBR reaction tank / % 64.29 74.09 78.02 79.54

[0069] Embodiment 3:

[0070] The fluidization of the suspended carrier is affected by the water flow velocity, air flow velocity, and agitator. Since the aeration methods of the first MBBR reaction tank and the second MBBR reaction tank are different, their air flow velocities are different, so it is necessary to match suitable suspended carriers for microbial attachment. The focus is on studying the effect of the specific gravity of the suspended carrier on fluidization. The first MBBR reaction tank and the second MBBR reaction tank were operated in parallel and studied separately. The test results are shown in Table 3. It can be seen from Table 3 that the fluidization effect of the suspended carrier directly affects the treatment performance. The better the fluidization, the better the mass transfer and oxygen transfer effect, and the best treatment performance. Since the bubble sizes of the first MBBR reaction tank and the second MBBR reaction tank are different, the rising flow rate is quite different, so the specific gravity of the most suitable suspended carrier is also slightly different. For the first MBBR reaction tank, the specific gravity is 1.05g / cm 3 The best is when the specific gravity is 1.15 g / cm 3 Therefore, in order to achieve the best treatment effect, different types of suspended carriers should be added during the actual operation.

[0071] Table 3 Effect of suspended carrier specific gravity on operation performance

[0072]

[0073] Example 4:

[0074] During the operation of the reaction system, the biofilm gradually thickens. In order to ensure an efficient mass transfer process, it is necessary to regularly strengthen the fluidization process to control the thickness of the biofilm. However, whether the treatment performance of the system will be temporarily affected during the defilming process needs to be explored. The test adopts the treatment system of the present invention. The influent is the aerobic pool in the biochemical section of a sewage plant in the north, with ammonia nitrogen of 45-50 mg / L and COD less than 50 mg / L, and it has been stably operated for more than 1 month. When the strong hydraulic shear stage is started, the frequency of cross-section water quality detection is increased to verify the impact of the strong hydraulic shear stage on the operation of the system. It can be seen from the test results that whether it is conventional operation or strong hydraulic shear operation, the effluent of the entire system can be stably lower than 1.5 mg / L, but in the strong hydraulic shear stage, the effluent ammonia nitrogen is affected and has an upward trend, and the maximum has reached 1.47 mg / L, which has the risk of exceeding the standard. Therefore, in the actual regulation process, it is necessary to adopt the measure of defilming one by one according to the different biofilm growth conditions of the first MBBR reaction tank and the second MBBR reaction tank, and increase the aeration volume through another reaction system to ensure the stability of the entire system. During actual regulation, in the strong fluidization stage of the second MBBR reaction pool, the oxygen supply to the first MBBR reaction pool is 1.1 to 1.2 times, and in the strong fluidization stage of the first MBBR reaction pool, the oxygen supply to the second MBBR reaction pool is 1.1 to 1.3 times.

[0075] Embodiment 5:

[0076] The design scale of a sewage plant in the north is 10000m 3 / d, treating municipal sewage, using MBBR-based AO process system, with a total residence time of 10h, including 5h in the aerobic zone and 5h in the anoxic zone. The aerobic zone adopts traditional aeration method, and air is supplied based on the inlet and outlet water quality requirements, while the anoxic zone adopts agitator method. The air demand in the aerobic zone is designed according to the inlet water quality, and the installed power density of the agitator in the anoxic zone is 10W / m 3 The long-term energy consumption is shown in Table 4 based on the test results. During actual operation, the aeration in the aerobic zone is 0.387 kWh / m 3 , stirring in the anoxic zone 0.050kWh / m 3 The power energy consumption in the anoxic zone is 13% of that in the aerobic zone.

[0077] Table 4 Energy consumption of different fluidization kinetic energy

[0078] Serial number Functional area Suspended carrier fluidization dynamics Tons of water and electricity consumption 1 Aerobic Aeration 0.387 2 Hypoxia Stirring 0.050

[0079] It can be seen from Example 5 that the energy consumption of using a stirrer for suspended fluidization is lower than that of aeration.

[0080] Embodiment 6:

[0081] Based on different aeration methods, the effects on the nitrification performance of MBBR and activated sludge method were studied. The test water was taken from the inlet of the aerobic pool of the mud membrane composite MBBR of a sewage plant, in which the COD was less than 50 mg / L. The activated sludge used in the test was taken from the end of the aerobic pool, and the suspended carrier was taken from the aerobic pool. The test adopted the SBR method, the MBBR reactor tank capacity was 50L, and the temperature was controlled at 20°C. The activated sludge method controlled the sludge concentration to 4000 mg / L, and the MBBR system controlled the filling rate to 50%. Agitators were installed to promote fluidization, and then micro-nano aeration was provided to the system. Regular sampling was performed to detect the ammonia nitrogen situation in the system until the ammonia nitrogen was lower than 1.5 mg / L, the reaction stopped, and the nitrification load was calculated. The results are shown in Table 5.

[0082] As can be seen from Table 5, under the premise of the same aeration volume, for the activated sludge system, the use of microporous aeration has a certain improvement over the perforated tube aeration, but the further use of micro-nano aeration has no significant improvement in nitrification performance. The main reason is that the limiting factor for the load increase of the activated sludge system is the functional bacteria, not oxygen. For the biofilm system, the nitrification performance is basically the same when using perforated tube aeration and microporous aeration, and is significantly higher than that of the activated sludge system. On the one hand, the reason is that the biofilm has a high efficiency in enriching functional bacteria and has a higher treatment efficiency; on the other hand, since the suspended carrier will cut the bubbles during the fluidization process, even if the perforated tube aeration provides large-aperture bubbles, it will become smaller due to the cutting of the suspended carrier. Therefore, the nitrification load of the system under perforated tube aeration and microporous aeration is basically the same. The further use of micro-nano aeration has significantly improved the nitrification performance, which is 1.54 times that of microporous aeration. The main reason is that smaller bubbles improve the oxygen utilization rate, promote the mass transfer of DO, and stimulate the activity of the functional bacteria in the inner layer of the biofilm, thereby increasing the nitrification load.

[0083] Table 5 Effects of different aeration modes on activated sludge and biofilm performance

[0084] Serial number Biochemical system Aeration method <![CDATA[曝气量 / L·h -1 > <![CDATA[Nitrification load kg / m 3 / d]]> 1 Activated sludge Perforated tube aeration 300 0.105 2 Activated sludge Micro-porous disc aeration 300 0.131 3 Activated sludge Micro-nano aeration 300 0.132 4 Biofilm (MBBR) Perforated tube aeration 300 0.317 5 Biofilm (MBBR) Microporous aeration 300 0.324 6 Biofilm (MBBR) Micro-nano aeration 300 0.498

[0085] Embodiment 7:

[0086] Demonstration project treatment scale 5000m 3 / d, has been running continuously for 1 year, and the sludge discharged from the mud hopper and mud collection area of ​​the solid-liquid separation area of ​​the system, as well as the residual sludge of the secondary sedimentation tank with the activated sludge method as the core adjacent to this project, have been detected and analyzed. The weight method, high-throughput analysis, and small-scale research methods were used respectively, and the results are shown in Table 6. As can be seen from Table 6, the sludge in the mud hopper area of ​​this system has a large specific gravity, SV30 is only 10%, and the MLVSS ratio is only 0.18, indicating that the inorganic matter is high and the activity is low. Compared with conventional sludge (residual sludge from the activated sludge method), the sludge in the mud collection area of ​​this system has a high MLVSS / MLSS ratio, which has reached 0.95, which is higher than the MLVSS / MLSS ratio reported in the biofilm. This also verifies that this part of the sludge is mainly composed of detached biofilms. At the same time, the substances with a larger specific gravity in the detached biofilms are precipitated in the mud hopper; in addition, no coagulation or flocculation agents are added to the solid-liquid separation area, which further increases the proportion of active microorganisms in the sludge in the mud collection area. From the perspective of sludge activity, the relative abundance of nitrifying bacteria in the SS in the sludge collection area is as high as 18.4%, and the nitrification load is 0.114kgNH3 / kgMLSS / d, which has better treatment performance. By reflux into the main reaction zone, the treatment performance of the main reaction zone can be greatly improved to cope with system shocks.

[0087] Table 6 Sludge performance analysis

[0088]

[0089] Parts described in the present invention can be realized by referring to the prior art.

[0090] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not intended to be limiting of the present application. As long as they are within the spirit of the present application, appropriate changes and modifications to the above embodiments should fall within the scope of protection of the claims of the present application.

Claims

1. An efficient treatment method based on MBBR, characterized in that: The following steps are involved: a. Prepare and install the required processing system The treatment system comprises a first MBBR reaction tank, a second MBBR reaction tank and a solid-liquid separation tank, wherein a first suspension carrier and a second suspension carrier are respectively added into the first MBBR reaction tank and the second MBBR reaction tank, a first micro-nano aerator and a second micro-nano aerator are respectively arranged at the bottom of the first MBBR reaction tank and the second MBBR reaction tank, the first micro-nano aerator is connected to a first micro-nano bubble generator, the second micro-nano aerator is connected to a second micro-nano bubble generator, and a stirrer is arranged in the first MBBR reaction tank and the second MBBR reaction tank; A bottom intercepting screen is provided between the first suspension carrier and the first micro-nano aerator, and between the second suspension carrier and the second micro-nano aerator; The wastewater to be treated enters from the first MBBR reaction tank and flows out from the solid-liquid separation tank; The solid-liquid separation tank comprises a tank body, and a mud bucket, a mud collecting tank and a mud scraper located in the tank body. The mud collecting tank is provided with a mud discharge pipe and a mud return pipeline, and the mud bucket is connected with the mud discharge pipe; the mud discharge pipe of the mud collecting tank and the mud return pipeline are respectively provided with a first control valve and a second control valve; The pore size of the first micro-nano aerator is 10-100 nm, and the pore size of the second micro-nano aerator is 10-20 μm; b. The sewage to be treated enters the first MBBR reaction tank, the agitator is turned on, the influent SS is lower than 50 mg / L, and micro-nano bubbles are provided to the first MBBR reaction tank and the second MBBR reaction tank through the first micro-nano aerator and the second micro-nano aerator respectively; c. Run: Normal operation state: close the second control valve, open the first control valve, and control the power density of the first MBBR reaction pool to 7-12W / m 3 The power density of the second MBBR reaction tank is 7-12W / m 3 , the aeration volume of the first MBBR reaction tank is 70% to 80% of the total aeration volume; Strong hydraulic shear stage I: close the second control valve, open the first control valve, and control the power density of the first MBBR reaction tank to 15-20W / m 3 The power density of the second MBBR reaction tank is 7-12W / m 3 The first MBBR reaction tank supplies oxygen according to the removal demand of oxygen-consuming pollutants, and the second MBBR reaction tank supplies oxygen at 1.1 to 1.3 times the removal demand of oxygen-consuming pollutants; Strong hydraulic shear stage II: close the second control valve, open the first control valve, and control the power density of the first MBBR reaction tank to 7-12W / m 3 The power density of the second MBBR reaction tank is 12-15W / m 3 The first MBBR reaction tank supplies oxygen at 1.1 to 1.2 times the removal demand of oxygen-consuming pollutants, and the second MBBR reaction tank supplies oxygen at the removal demand of oxygen-consuming pollutants.

2. An efficient treatment method based on MBBR according to claim 1, characterized in that: In step c, for the MBBR reaction pool with the core of removing organic matter, the strong hydraulic shear stage I is started every 10 to 15 days, and each time it is started for 2 to 3 hours; the hydraulic shear stage II is started every 20 to 25 days, and each time it is started for 1.5 to 2.0 hours; for the MBBR reaction pool with the core of removing ammonia nitrogen, the strong hydraulic shear stage I is started every 20 to 25 days, and each time it is started for 1 to 2 hours, and the hydraulic shear stage II is started every 35 to 40 days, and each time it is started for 1 to 1.5 hours; When the residence time of oxygen-consuming pollutants in the inlet water exceeds 1.3 times the design value for three consecutive times, the second control valve is opened and the first control valve is closed. When the residence time of oxygen-consuming pollutants in the inlet water is lower than 1.1 times the design value for three consecutive times, the second control valve is closed and the first control valve is opened.

3. The efficient treatment method based on MBBR according to claim 1, characterized in that: The mud bucket and the mud collecting trough are respectively located at the bottom and the upper part of the pool body, and the mud scraper rotates clockwise.

4. The efficient treatment method based on MBBR according to claim 1, characterized in that: The volume of the first MBBR reaction tank accounts for 60% to 70% of the total volume of the first MBBR reaction tank and the second MBBR reaction tank, and removes 80% to 90% of oxygen-consuming pollutants in the influent.

5. The efficient treatment method based on MBBR according to claim 1, characterized in that: The power density of the agitator in the first MBBR reaction tank is 7-20 W / m 3 The power density of the agitator in the second MBBR reaction tank is 7-15W / m 3 .

6. The MBBR-based efficient treatment method according to claim 1, characterized in that: The specific gravity of the first suspension carrier is 1.05-1.10 g / cm 3 The specific gravity of the second suspension carrier is 1.15-1.20 g / cm 3 The first suspension carrier and the second suspension carrier are both cylindrical carriers with a thickness of 3 to 5 mm and a pore size of 4 to 5 mm.

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