Composite MABR treatment device for sewage with a low carbon-nitrogen ratio

Abstract

The present invention discloses a composite MABR treatment device for sewage with a low carbon-nitrogen ratio, which comprises a reaction tank, a plurality of membrane modules located inside the reaction tank, as well as an aeration system, a cleaning system and a sewage pipeline system. There are n baffle plates inside the reaction tank, and each baffle plate is arranged at equal intervals and divides the reaction tank into n + 1 reaction zones. The membrane module includes membrane frames on both sides thereof and hollow fiber membrane filaments located in the middle of the membrane frames. The present invention forms a unique sewage treatment flow direction, improves the treatment area per unit of membrane filaments, can meet the oxygen demand of the system through a relatively small membrane area, greatly improves the treatment effect, and only uses micro-aeration with the aeration pressure at the air inlet end being less than 10 kPa, without worrying about physical damage caused by a relatively high pressure of the membrane module, saving a large amount of aeration costs and maintenance costs. At the same time, no carbon source needs to be added during the denitrification process, saving a large amount of carbon source addition costs.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and specifically relates to a composite MABR treatment device for sewage with a low carbon-nitrogen ratio. Background Art

[0002] Membrane Aerated Biofilm Reactor (MABR) is a new type of biofilm water treatment technology. In MABR, the aeration membrane can supply oxygen efficiently, and microorganisms attach and grow on the aeration membrane to form a biofilm. Pollutants in wastewater can be effectively removed under the action of microorganisms on the biofilm. MABR has the advantages of high oxygen mass transfer efficiency, low sludge yield, and low operation and maintenance costs, and has congenital advantages in treating highly volatile wastewater and nitrogen removal.

[0003] There are still several problems to be solved in the engineering application of this technology for treating sewage with a low C / N ratio.

[0004] (1) Similar to traditional biological sewage treatment methods, MABR still needs to add a large amount of carbon source to achieve good nitrogen removal effect when treating sewage with a low C / N ratio, which causes a large amount of resource waste.

[0005] (2) In existing MABR projects, the oxygen supply pressure of the membrane module is relatively large. On the one hand, it causes a large amount of energy consumption, and on the other hand, long-term operation under a large pressure may damage the membrane module.

[0006] (3) In existing MABR projects, in order to obtain good treatment effects, usually the membrane area is relatively large and a large membrane box is required for placement, which results in that existing MABR projects often require a large floor area and high construction costs.

[0007] (4) In existing MABR projects, problems such as membrane blockage, membrane fouling, and large biofilm thickness may occur, and these problems will reduce the treatment effect of MABR.

[0008] Therefore, it is still necessary to further solve the existing problems of MABR, and then utilize the technical advantages of MABR, and at the same time combine other processes to develop a new type of composite sewage treatment technology, so as to achieve low-consumption and high-efficiency treatment of sewage with a low C / N ratio. Summary of the Invention

[0009] In view of the above problems, the present invention provides a composite MABR treatment device for sewage with a low carbon-nitrogen ratio.

[0010] The technical solution of the present invention is as follows:

[0011] A composite MABR treatment device for sewage with a low carbon-nitrogen ratio includes a reaction tank, a plurality of membrane modules located inside the reaction tank, and an aeration system, a cleaning system, and a sewage pipeline system;

[0012] There are n baffle plates inside the reaction tank, where n is an integer greater than 1. Each of the baffle plates is arranged at equal intervals and divides the reaction tank into n + 1 reaction zones. The tops of the odd-numbered baffle plates are open for overflow, and the bottoms of the even-numbered baffle plates are open for overflow, so that the sewage forms a continuous Z-shaped flow direction inside the reaction tank. There are two membrane modules, one above the other, in each reaction zone.

[0013] The membrane module includes membrane frames on both sides thereof and hollow fiber membrane filaments in the middle of the membrane frames. One end of the membrane frame is the air inlet end, and the other end is the air outlet end. The air inlet ends of all the membrane frames are on the same side, and the aeration system is correspondingly arranged above this side.

[0014] The aeration system includes an air compressor, a main pipeline, and n first air inlet pipes. Each of the first air inlet pipes is correspondingly connected to the membrane module provided in each reaction zone.

[0015] The cleaning system includes n second air inlet pipes connected to the main pipeline. At the end of each of the second air inlet pipes, a first cleaning spray head is connected inside each reaction zone. The bottom of the first cleaning spray head is connected to a second cleaning spray head through a conduit.

[0016] With the left side as the water inlet end and the right side as the water outlet end, the sewage pipeline system includes a water inlet pump and a water inlet pipe at the left bottom of the reaction tank, and a circulation pipe at the right top of the reaction tank.

[0017] Further, at the air outlet end of the first cleaning spray head in each reaction zone, it points to the side where one of the membrane modules above is located, and at the air outlet end of the second cleaning spray head, it points to the side where one of the membrane modules below is located. The circulation pipe corresponds to one reaction zone at the right end. A circulation pump is provided in the middle of the circulation pipe, and a drain pipe is provided at the upper part of the side wall at the right end of the reaction tank.

[0018] Note: The membrane module is cleaned by the cleaning spray head, and the sewage circulation is realized through the circulation pipe.

[0019] Further, the lower end of the first air inlet pipe first penetrates through the air inlet end membrane frame of one of the membrane modules above, and then docks with the air inlet end membrane frame of one of the membrane modules below. The first air inlet pipe is provided with air outlet holes inside the air inlet end membrane frames of the two membrane modules, and several air guiding holes are provided inside the air inlet end membrane frames of the membrane modules.

[0020] Note: The hollow fiber membrane filaments of the membrane module are supplied with air through the first air inlet pipe and the air outlet holes.

[0021] Further, valves are provided on both the first air inlet pipe and the second air inlet pipe.

[0022] Description: The gas injection flow rate and opening / closing are controlled by a valve.

[0023] Further, n is 3. The three first cleaning nozzles are respectively located inside the left side wall of the reaction tank, inside the right side wall of the first deflector plate, and inside the chute provided on the left side wall of the third deflector plate. The first cleaning nozzles are all slidably connected to the chute. A push rod motor is provided on the front inner wall of the reaction tank corresponding to each first cleaning nozzle. The output end of the push rod motor is fixedly connected to the outside of each first cleaning nozzle to drive the first cleaning nozzle to slide along the chute and drive the second cleaning nozzle to move synchronously.

[0024] Description: The value of n can be reasonably adjusted according to the size of the reaction tank. The larger the volume of the reaction tank, the larger n is, and the more membrane modules are arranged, which is suitable for large-scale sewage treatment. When n is 3, 6 groups of membrane modules can effectively treat sewage, and the structure is compact and convenient for management and maintenance. By designing the two cleaning nozzles to be movable, the cleaning effect can be improved, and the biofilm on the hollow fiber membrane filaments can be evenly cleaned by using hydraulic disturbance and air flow impact.

[0025] Preferably, filter plates are provided on the tops of the first deflector plate and the third deflector plate. Residue storage boxes are provided on the inner sides of the tops of the first deflector plate and the third deflector plate. The residue storage boxes are located on the left side of the filter plates. The residue storage boxes are slidably connected to the inner cavity of the deflector plates. The bottom of the cavity is communicated with the chute. A corrugated plate is provided at the bottom of the residue storage box. The corrugated plate extends to the bottom of the cavity and is butted against the end of the first cleaning nozzle, so as to push the corrugated plate to slide up and down through the sliding of the first cleaning nozzle. A plurality of cleaning brushes are provided on the top of the residue storage box. The cleaning brushes are fixedly connected to the left side wall of the top of the residue storage box. The right side of the cleaning brushes is butted against the filter plate to clean the filter plate during the up and down sliding process.

[0026] Description: The cleaned biofilm residue is blocked by the filter plate, and the scraping and collection of the biofilm residue are completed in cooperation with the up and down movement of the residue storage box, so as to reduce the influence of the biofilm residue on sewage treatment. Moreover, the residue storage box can be taken out regularly for cleaning without cleaning every time the hollow fiber membrane filaments are cleaned, making the whole device easy to maintain and avoiding deposition in the reaction tank.

[0027] Preferably, a spring group is provided on each of the front and rear sides of the bottom of the residue storage box. The end of the spring group is connected with a slider, and the slider slides up and down inside the limit slots provided on the front and rear sides of the cavity.

[0028] Description: The arrangement of the spring group and the slider can enable the residue storage box to move in all directions irregularly during movement, so as to cooperate with the cleaning brush to clean the filter plate.

[0029] Furthermore, the hollow fiber membrane filaments are domesticated with aerobic activated sludge and anaerobic ammonium oxidation activated sludge to form a biofilm. The biofilm sequentially includes an aerobic layer, an anoxic layer, and an anaerobic layer from the inside in the direction away from the hollow fiber aeration membrane. The biofilm is composed of microorganisms, extracellular polymeric substances, bacteria, and fungi.

[0030] Note: A large number of ammonia-oxidizing bacteria are enriched in the aerobic layer and the anoxic layer, and a large number of anaerobic ammonium-oxidizing bacteria are enriched in the anoxic layer. Pollutants (NH4 + -N) in the sewage enter from the outside of the biofilm to the inside of the biofilm, and half of the NH4 + -N is consumed under the action of ammonia-oxidizing bacteria in the inner aerobic tank and the anoxic layer, and the corresponding amount of NO2 - -N accumulates. The remaining NH4 + -N and NO2 - -N enter the anaerobic layer and are denitrified under the action of anaerobic ammonium-oxidizing bacteria.

[0031] Furthermore, a sludge discharge pipe is provided at the lower part of the side wall at the right end of the reaction tank. The two sides of the bottom of the membrane frame are fixed by clamping blocks. The clamping block located on the leftmost side is fixedly arranged on the inner side wall of the reaction tank, and the remaining clamping blocks are fixedly arranged on the baffle plate. A pore for the catheter to pass through and move is left between the membrane module and the baffle plate.

[0032] Note: The remaining residual sludge and solid waste in the reaction tank are discharged through the sludge discharge pipe.

[0033] Furthermore, in one reaction area, an exhaust pipe is provided on the air outlet end membrane frame of the membrane module located below. The exhaust pipe penetrates through the air outlet end membrane frame of the membrane module located above from above, and exhaust holes are provided inside the air outlet end membrane frames of the exhaust pipe corresponding to the two membrane modules. For each reaction area, the membrane modules located above are on the same horizontal line, and the membrane modules located below are on the same horizontal line.

[0034] Note: The pressure at the air outlet end of the membrane module is controlled through the exhaust pipe.

[0035] The beneficial effects of the present invention are as follows:

[0036] (1) The composite MABR treatment device for low carbon-nitrogen ratio sewage of the present invention classifies the membrane module structure in detail, forms a unique sewage treatment flow direction, increases the treatment area per unit membrane filament, realizes the oxygen demand of the system through a smaller membrane area, greatly improves the treatment effect, and only uses micro-aeration with an aeration pressure at the air inlet end less than 10 kPa, without worrying about physical damage caused by a higher pressure of the membrane module, saving a large amount of aeration costs and maintenance costs. At the same time, no carbon source needs to be added during the denitrification process, saving a large amount of carbon source addition costs.

[0037] (2) The composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention can clean the membrane module through the cleaning system or prevent the biofilm on the membrane module from growing too thick, ensuring the overall stable operation effect of the device. It has good treatment effect for low C / N sewage, low construction and operation costs, and has good engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the overall structural schematic diagram of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0039] Figure 2 is the internal structural schematic diagram of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0040] Figure 3 is the front view of the internal structure of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0041] Figure 4 is the structural schematic diagram of the connection between the first air inlet pipe and the membrane frame of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0042] Figure 5 is the structural schematic diagram of the connection between the exhaust pipe and the membrane frame of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0043] Figure 6 is the structural schematic diagram of the membrane module of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0044] Figure 7 is the structural schematic diagram of the biofilm of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0045] Figure 8 is the structural schematic diagram of the cleaning system of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0046] Figure 9 is the structural schematic diagram of the top of the slag storage box of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0047] Figure 10 is the internal structural schematic diagram of the slag storage box of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention;

[0048] Figure 11 is the structural schematic diagram of the connection between the two sides of the slag storage box and the inside of the cavity of the composite MABR treatment device for low-carbon and nitrogen ratio sewage of the present invention.

[0049] Among them, 1 - reaction tank, 11 - baffle plate, 12 - chute, 13 - filter plate, 14 - cavity, 15 - limiting groove, 16 - sludge discharge pipe, 2 - membrane module, 21 - membrane frame, 22 - hollow fiber membrane filaments, 23 - air guide hole, 24 - exhaust pipe, 25 - exhaust hole, 26 - clamping block, 3 - aeration system, 31 - air compressor, 32 - main pipeline, 33 - first intake pipe, 34 - air outlet hole, 4 - cleaning system, 41 - second intake pipe, 42 - first cleaning spray head, 43 - conduit, 44 - second cleaning spray head, 45 - push rod motor, 5 - sewage pipeline system, 51 - feed water pump, 52 - feed water pipe, 53 - circulation pipe, 54 - circulation pump, 55 - drain pipe, 6 - valve, 7 - slag storage box, 71 - corrugated plate, 72 - cleaning brush, 73 - spring group, 74 - slider, 8 - biofilm, 81 - aerobic layer, 82 - anoxic layer, 83 - anaerobic layer. Detailed implementation manner

[0050] Example 1

[0051] As Figure 1 and 2 shown, a composite MABR treatment device for low carbon-nitrogen ratio sewage includes a reaction tank 1, a plurality of membrane modules 2 located inside the reaction tank 1, and an aeration system 3, a cleaning system 4 and a sewage pipeline system 5;

[0052] As Figure 3 shown, there are 3 baffle plates 11 inside the reaction tank 1. Each baffle plate 11 is arranged at equal intervals and divides the reaction tank 1 into 4 reaction zones. The top of the odd baffle plates 11 has an open overflow, and the bottom of the even baffle plates 11 has an open overflow, so that the sewage forms a continuous Z-shaped flow direction inside the reaction tank 1. There are two membrane modules 2, one above the other, in each reaction zone;

[0053] As Figures 4 to 7 shown, the membrane module 2 includes membrane frames 21 on both sides and hollow fiber membrane filaments 22 in the middle of the membrane frames 21. One end of the membrane frame 21 is the air inlet end, and the other end is the air outlet end. The air inlet ends of each membrane frame 21 are on the same side, and an aeration system 3 is correspondingly arranged above this side. The hollow fiber membrane filaments 22 are domesticated with aerobic activated sludge and anaerobic ammonium oxidation activated sludge to form a biofilm 8. The biofilm 8 is successively an aerobic layer 81, an anoxic layer 82 and an anaerobic layer 83 from the inside along the direction away from the hollow fiber aeration membrane. The biofilm 8 is composed of microorganisms, extracellular polymers, bacteria and fungi. In one reaction zone, an exhaust pipe 24 is provided on the air outlet end membrane frame 21 of the membrane module 2 located below. The exhaust pipe 24 penetrates through the air outlet end membrane frame 21 of the membrane module 2 located above from above, and exhaust holes 25 are provided inside the exhaust pipe 24 corresponding to the air outlet end membrane frames 21 of the two membrane modules 2. For each reaction zone, the membrane modules 2 located above are on the same horizontal line, and the membrane modules 2 located below are on the same horizontal line;

[0054] Note: The aerobic activated sludge and anaerobic ammonium oxidation activated sludge used in the process of biofilm formation on the membrane module 2 are from a sewage treatment plant. The sludge domestication process is as follows: First, prepare an ammonia-nitrogen solution with a certain concentration using ammonium chloride. Take a certain amount of aerobic layer activated sludge and mix it with an equal amount of the above ammonia-nitrogen solution, and add it to the reaction tank 1. Maintain the aeration pressure of the membrane module 2 below 10 kPa, with no influent or effluent. Set the circulation pump 54 to circulate to ensure that the sludge is in a suspended state, with a circulation ratio of 1:1, and carry out the enrichment process of ammonia-oxidizing bacteria. Replace the sludge-water mixture in the reaction tank 1 every two days, and take the solution in the reaction tank 1 to measure the concentrations of ammonia-nitrogen and nitrite-nitrogen. This process lasts for 10 - 15 days. When a visible biofilm forms on the membrane module 2 and the removal rate of ammonia-nitrogen and the accumulation rate of nitrite-nitrogen are close to 50%, it can be considered that the enrichment of ammonia-oxidizing bacteria is successful. Subsequently, carry out the enrichment of anaerobic ammonium oxidation bacteria. Take a certain amount of anaerobic ammonium oxidation activated sludge, mix it with an equal amount of the above ammonia-nitrogen solution, and then add the sludge-water mixture to the reaction tank 1. Maintain the aeration pressure of the membrane module 2 below 5 kPa, and maintain the DO in the reaction tank 1 below 0.5 mg / L. Set the circulation pump 54 to circulate to ensure that the sludge is in a suspended state, with a circulation ratio of 1:1, and carry out the enrichment process of anaerobic ammonium oxidation bacteria. Replace the sludge-water mixture in the reaction tank 1 every two days, and take the solution in the reaction tank 1 to measure the concentrations of TN, ammonia-nitrogen, nitrate-nitrogen, and nitrite-nitrogen, and analyze the TN removal situation in the reaction tank 1. This process lasts for 10 - 15 days. When a visible biofilm forms on the membrane module 2 and the removal rate of TN exceeds 70%, it can be considered that the enrichment of anaerobic ammonium oxidation bacteria is successful.

[0055] The domestication of the sludge can form a visible biofilm 8, whose main components include microorganisms, extracellular polymeric substances, bacteria, fungi, etc. These components all come from aerobic activated sludge and anaerobic ammonium oxidation activated sludge. In the membrane module 2, the oxygen in the membrane cavity can achieve oxygen mass transfer through the adsorption and desorption process of the membrane wall. Therefore, the closer to the membrane, the higher the oxygen concentration, and thus the aerobic layer 81, anoxic layer 82, and anaerobic layer 83 of the biofilm 8 are formed in sequence from the inside along the direction away from the hollow fiber aeration membrane.

[0056] As Figure 2 and 3As shown in the figure, the aeration system 3 includes an air compressor 31, a main pipeline 32, and three first air inlet pipes 33. The air compressor 31 is a commercially available product. Each of the first air inlet pipes 33 is connected to the membrane module 2 provided in each reaction area in a one-to-one correspondence. The lower end of the first air inlet pipe 33 first penetrates the air inlet end membrane frame 21 of a membrane module 2 located above, and then docks with the air inlet end membrane frame 21 of a membrane module 2 located below. The first air inlet pipe 33 is provided with air outlet holes 34 inside the air inlet end membrane frames 21 of two membrane modules 2. The air inlet end membrane frame 21 of the membrane module 2 is provided with a number of air guide holes 23. The two sides of the bottom of the membrane frame 21 are fixed by clamping blocks 26. The clamping block 26 located on the leftmost side is fixedly arranged on the inner side wall of the reaction tank 1, and the remaining clamping blocks 26 are fixedly arranged on the flow guiding plate 11. A gap is left between the membrane module 2 and the flow guiding plate 11 for the catheter 43 to pass through and move;

[0057] The cleaning system 4 includes three second air inlet pipes 41 connected to the main pipeline 32. The end of each second air inlet pipe 41 is connected with a first cleaning spray head 42 corresponding to the inside of each reaction area. The bottom of the first cleaning spray head 42 is connected with a second cleaning spray head 44 through a catheter 43. In each reaction area, the air outlet end of the first cleaning spray head 42 points to the side where a membrane module 2 located above is located, and the air outlet end of the second cleaning spray head 44 points to the side where a membrane module 2 located below is located. Valves 6 are provided on both the first air inlet pipe 33 and the second air inlet pipe 41. The valves 6 are commercially available solenoid valves;

[0058] As Figure 1 shown, with the left side as the water inlet end and the right side as the water outlet end, the sewage pipeline system 5 includes a water inlet pump 51 and a water inlet pipe 52 located on the left side of the bottom of the reaction tank 1, and a circulation pipe 53 located at the top right of the reaction tank 1. The circulation pipe 53 corresponds to a reaction area at the right end. A circulation pump 54 is provided in the middle of the circulation pipe 53. The circulation pump 54 is a commercially available circulation pump for sewage treatment. A drain pipe 55 is provided on the upper part of the side wall at the right end of the reaction tank 1, and a sludge discharge pipe 16 is provided on the lower part of the side wall at the right end of the reaction tank 1.

[0059] Example 2

[0060] The difference between this example and Example 1 is that the first cleaning spray head 42 and the second cleaning spray head 44 of the cleaning system 3 are movably arranged. Specifically:

[0061] As Figure 3 and 8As shown in the figure, three first cleaning nozzles 42 are respectively located inside the left side wall of the reaction tank 1, on the right side wall of the first baffle 11, and in the chute 12 provided on the left side wall of the third baffle 11. The first cleaning nozzles 42 are all slidably connected to the chute 12. At the corresponding positions of the front inner wall of the reaction tank 1 for each first cleaning nozzle 42, there is a push rod motor 45. The push rod motor 45 is a commercially available product. The output end of the push rod motor 45 is fixedly connected to the outside of each first cleaning nozzle 42 for driving the first cleaning nozzle 42 to slide along the chute 12 and driving the second cleaning nozzle 44 to move synchronously.

[0062] As Figures 8 to 11 As shown in the figure, filter plates 13 are provided at the tops of both the first baffle 11 and the third baffle 11. Inside the tops of the first baffle 11 and the third baffle 11, there are slag storage boxes 7. The slag storage boxes 7 are located on the left side of the filter plates 13. The slag storage boxes 7 are slidably connected to the inner cavity 14 of the baffle 11. The bottom of the cavity 14 is communicated with the chute 12. A corrugated plate 71 is provided at the bottom of the slag storage box 7. The corrugated plate 71 extends to the bottom of the cavity 14 and is butted against the end of the first cleaning nozzle 42, for pushing the corrugated plate 71 to slide up and down by the sliding of the first cleaning nozzle 42. A number of cleaning brushes 72 are provided at the top of the slag storage box 7. The cleaning brushes 72 are fixedly connected to the left side wall of the top of the slag storage box 7. The right side of the cleaning brushes 72 is butted against the filter plate 13 for cleaning the filter plate 13 during the up and down sliding process. On both sides of the bottom of the slag storage box 7, there is a spring group 73 in the front and back respectively. The end of the spring group 73 is connected with a slider 74. The slider 74 slides up and down inside the limiting grooves 15 provided on the front and back sides of the cavity 14.

[0063] The specific working mode of the improved cleaning system 3 is as follows:

[0064] Turn on each first cleaning nozzle 42 and the second cleaning nozzle 44 in sequence from left to right. First, turn on the two first cleaning nozzles 42 and the second cleaning nozzle 44 located on the leftmost side. Open the valve 6 of the corresponding second air inlet pipe 41 to make the first cleaning nozzle 42 and the second cleaning nozzle 44 spray gas, and use hydraulic disturbance and air flow impact to uniformly clean the biofilm on the hollow fiber membrane filaments 22. At the same time, turn on the push rod motor 45 to drive the first cleaning nozzle 42 to slide in the chute 12 on the inner wall of the reaction tank 1, and synchronously drive the second cleaning nozzle 44 to move through the conduit 43, so as to realize continuous and all-round cleaning of the hollow fiber membrane filaments 22. The fallen biofilm residues float up with the water flow, are intercepted by the filter plate 13 and stay on the filter plate 13.

[0065] After the cleaning of the first reaction area is completed, the cleaning of the two membrane modules 2 in the next reaction area is started. In the same way, the first cleaning nozzle 42 and the second cleaning nozzle 44 spray gas and move. Different from the previous time, when the first cleaning nozzle 42 moves, it will push the corrugated plate 71 to move up and down. According to the wavy lines on the corrugated plate 71, the slag storage box 7 is driven to move up and down. At the same time, the cleaning brush 72 will brush the filter plate 13 up and down, scraping off the biofilm residues attached to it and falling into the slag storage box 7;

[0066] On this basis, since there are gaps between the cleaning brushes 72 (in order to enable the biofilm residues to be scraped off and fall into the slag storage box 7), in order to ensure that the corresponding gaps on the filter plate 13 can also be well cleaned, we use a spring to overcome this problem: when the first cleaning nozzle 42 moves and pushes the corrugated plate 71, there will be a forward force, which will push the slag storage box 7 to move a short distance. Therefore, through the setting of the slider 74 and the spring group 73, this short displacement is just utilized, so that each cleaning brush 72 can clean the corresponding gaps on the filter plate 13. At the same time, the setting of the limit groove 15 can also offset the up and down sliding of the slider 74 and keep the whole slag storage box 7 stable without dislocation;

[0067] At the same time, the biofilm residues shed after the second cleaning fall on the third filter plate 13, and can be scraped off when the third group of biofilm cleaning is started in the same way;

[0068] It should be noted that it is not necessary to take out the slag storage box 7 for cleaning after each scraping. After about 3 to 5 cleaning cycles, it can be taken out and cleaned uniformly. The slag storage box 7 can be taken out of the cavity 14 by lifting it upward.

[0069] Embodiment 3

[0070] The difference between this embodiment and Embodiment 1 is that:

[0071] The number of the deflector plates 11 provided is 2, and the corresponding first air inlet pipe 33 and second air inlet pipe 41 are also 2.

[0072] Embodiment 4

[0073] The difference between this embodiment and Embodiment 1 is that:

[0074] The number of the deflector plates 11 provided is 5, and the corresponding first air inlet pipe 33 and second air inlet pipe 41 are also 5.

[0075] Experimental Example

[0076] The implementation method of the composite MABR treatment device for low C / N actual sewage mainly includes the following implementation steps:

[0077] (1) Construction of the composite MABR: First, the membrane module 2 in reaction tank 1 was domesticated for microbial film formation using the activated sludge from the aerobic tank of a sewage treatment plant to achieve the enrichment of ammonia-oxidizing bacteria. During this process, the membrane module 2 was micro-aerated through the aeration system 3. Subsequently, the membrane module 2 was further domesticated for microbial film formation using anaerobic ammonium oxidation activated sludge to achieve the enrichment of anaerobic ammonium-oxidizing bacteria. There was no aeration in the membrane module 2 during this process.

[0078] (2) Operation of the composite MABR system: After successful domestication of ammonia-oxidizing bacteria and anaerobic ammonium-oxidizing bacteria on the membrane module 2, normal continuous-flow experiments were started to treat low C / N sewage. In the continuous-flow experiments, micro-aeration was achieved for the membrane module 2 through the aeration system 3.

[0079] Among them, in the domestication of ammonia-oxidizing bacteria in step (1), the aeration pressure at the inlet end of the aeration system 3 was lower than 10 kPa, there was no influent and effluent, the ratio of sludge to sewage was 1:1, and a circulation pump 54 was set to circulate to ensure that the sludge was in a suspended state, and the circulation ratio was 1:1. There was no aeration in the membrane module 2 during the enrichment process of anaerobic ammonium-oxidizing bacteria. The entire microbial film formation process lasted for 2 to 4 weeks. The domestication effect of ammonia-oxidizing bacteria was measured by the accumulation amount of NO2 - -N and the removal effect of NH4 + -N, as well as the changes in the biofilm 2 observed with the naked eye; the enrichment of anaerobic ammonium-oxidizing bacteria was measured by the removal effects of COD and TN and the changes in the biofilm 2 observed with the naked eye.

[0080] In step (2), the cleaning system 4 needs to be started according to the pollution situation of the membrane module 2 or the thickness of the biofilm. The cleaning system 4 cleans the membrane module 2 through hydraulic disturbance to make the biofilm thinner.

[0081] Optimize the operating parameters according to the treatment effect of the composite MABR. The main operating parameters include the aeration pressure at the inlet end, hydraulic retention time, water temperature, circulation ratio, etc.

[0082] Quantitatively control the aeration pressure at the inlet end (2 - 10 kPa) through the valve 6. The aeration pressure gradient at the inlet end can be controlled as 2 kPa, 4 kPa, 6 kPa, 8 kPa, 10 kPa.

[0083] Regulate the inlet water flow by adjusting the rotation speed of the inlet pump 51, so as to quantitatively control the hydraulic retention time (4 - 12 h). The hydraulic retention time gradient can be controlled as 12 h, 8 h, 4 h.

[0084] Regulate the circulation flow by adjusting the rotation speed of the circulation pump 54, so as to quantitatively control the circulation ratio (100 - 200%). The circulation ratio gradient can be controlled as 1:1, 2:1.

[0085] Precisely control the water temperature (10 - 35°C) in the composite MABR through the bottom insulation layer of the reaction tank 1. In the room temperature experiment, the water temperature gradient can be controlled at 25°C, 30°C, and 35°C. In the low temperature experiment, the water temperature gradient can be controlled at 25°C, 20°C, 15°C, and 10°C.

Claims

1. A composite MABR treatment device for sewage with a low carbon-nitrogen ratio, characterized in that, It includes a reaction tank (1), several membrane modules (2) located inside the reaction tank (1), an aeration system (3), a cleaning system (4), and a sewage pipeline system (5); Inside the reaction tank (1), n baffle plates (11) are provided, where n is an integer greater than 1. Each of the baffle plates (11) is arranged at equal intervals and divides the reaction tank (1) into n + 1 reaction zones. The tops of the odd baffle plates (11) are open for overflow, and the bottoms of the even baffle plates (11) are open for overflow, so that the sewage forms a continuous Z-shaped flow direction inside the reaction tank (1). Two membrane modules (2) are provided, one above the other, in each reaction zone; The membrane module (2) includes membrane frames (21) on both sides thereof and hollow fiber membrane filaments (22) in the middle of the membrane frames (21). One end of the membrane frame (21) is the air inlet end, and the other end is the air outlet end. The air inlet ends of each membrane frame (21) are on the same side, and the aeration system (3) is correspondingly arranged above this side; The aeration system (3) includes an air compressor (31), a main pipeline (32), and n first air inlet pipes (33). Each of the first air inlet pipes (33) is connected in one-to-one correspondence with the membrane modules (2) provided in each reaction zone; The cleaning system (4) includes n second air inlet pipes (41) connected to the main pipeline (32). At the end of each of the second air inlet pipes (41), a first cleaning nozzle (42) is connected corresponding to the inside of each reaction zone. The bottom of the first cleaning nozzle (42) is connected to a second cleaning nozzle (44) through a conduit (43); Taking the left side as the water inlet end and the right side as the water outlet end, the sewage pipeline system (5) includes a water inlet pump (51) and a water inlet pipe (52) at the left bottom of the reaction tank (1), and a circulation pipe (53) at the right top of the reaction tank (1); The n is 3. The three first cleaning nozzles (42) are respectively located in the chutes (12) provided on the inner side of the left wall of the reaction tank (1), the right side wall of the first baffle plate (11), and the left side wall of the third baffle plate (11). The first cleaning nozzles (42) are all slidably connected to the chutes (12). A push rod motor (45) is provided on the front inner wall of the reaction tank (1) corresponding to each first cleaning nozzle (42). The output end of the push rod motor (45) is fixedly connected to the outside of each first cleaning nozzle (42) to drive the first cleaning nozzle (42) to slide along the chute (12) and drive the second cleaning nozzle (44) to move synchronously; Filter plates (13) are provided at the tops of the first and third flow guide plates (11). Scrap storage boxes (7) are provided inside the tops of the first and third flow guide plates (11). The scrap storage box (7) is located on the left side of the filter plate (13). The scrap storage box (7) is slidably connected to the inner cavity (14) of the flow guide plate (11). The bottom of the cavity (14) communicates with the chute (12). A corrugated plate (71) is provided at the bottom of the scrap storage box (7). The corrugated plate (71) extends to the bottom of the cavity (14) and is docked with the end of the first cleaning nozzle (42) for sliding the first cleaning nozzle (42) to push the corrugated plate (71) to slide up and down. A number of cleaning brushes (72) are provided at the top of the scrap storage box (7). The cleaning brushes (72) are fixedly connected to the left side wall of the top of the scrap storage box (7). The right side of the cleaning brush (72) is docked with the filter plate (13) for cleaning the filter plate (13) during the up and down sliding process.

2. The composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that, In each of the reaction zones, the gas outlet end of the first cleaning nozzle (42) points to the side where one of the membrane modules (2) located above is. The gas outlet end of the second cleaning nozzle (44) points to the side where one of the membrane modules (2) located below is. The circulation pipe (53) corresponds to one of the reaction zones at the right end. A circulation pump (54) is provided in the middle of the circulation pipe (53). A drain pipe (55) is provided at the upper part of the side wall at the right end of the reaction tank (1).

3. The composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, wherein, The lower end of the first air inlet pipe (33) first penetrates through the air inlet end membrane frame (21) of one of the membrane modules (2) located above, and then is docked with the air inlet end membrane frame (21) of one of the membrane modules (2) located below. Air outlet holes (34) are provided inside the air inlet end membrane frames (21) of the first air inlet pipe (33) corresponding to the two membrane modules (2). A number of air guide holes (23) are provided inside the air inlet end membrane frame (21) of the membrane module (2).

4. The composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, wherein, Valves (6) are provided on both the first air inlet pipe (33) and the second air inlet pipe (41).

5. The composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that, On both sides of the bottom of the scrap storage box (7), a spring group (73) is provided at the front and back respectively. The end of the spring group (73) is connected to a slider (74). The slider (74) slides up and down inside the limit slots (15) provided on the front and back sides of the cavity (14).

6. The composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, wherein, The hollow fiber membrane filaments (22) are domesticated with aerobic activated sludge and anaerobic ammonia oxidation activated sludge to form a biofilm (8). The biofilm (8) is, from the inside, in the direction away from the hollow fiber aeration membrane, an aerobic layer (81), an anoxic layer (82), and an anaerobic layer (83) in sequence. The biofilm (8) is composed of microorganisms, extracellular polymers, bacteria, and fungi.

7. The composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that, A sludge discharge pipe (16) is provided at the lower part of the side wall at the right end of the reaction tank (1). The two sides of the bottom of the membrane frame (21) are fixed by clamping blocks (26). The clamping block (26) located at the leftmost side is fixedly arranged on the inner side wall of the reaction tank (1), and the remaining clamping blocks (26) are fixedly arranged on the flow guide plate (11). A pore for the catheter (43) to pass through and move is left between the membrane module (2) and the flow guide plate (11).

8. The composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that, In one of the reaction regions, an exhaust pipe (24) is provided on the air outlet end membrane frame (21) of the membrane module (2) located below. The exhaust pipe (24) penetrates through the air outlet end membrane frame (21) of the membrane module (2) located above from above, and exhaust holes (25) are provided in the exhaust pipe (24) corresponding to the air outlet end membrane frames (21) of the two membrane modules (2). For each reaction region, the membrane modules (2) located above are on the same horizontal line, and the membrane modules (2) located below are on the same horizontal line.

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