Composite MABR treatment device for sewage with low carbon nitrogen ratio

Abstract

The invention discloses a composite MABR treatment device for sewage with low carbon-nitrogen ratio, which comprises a reaction tank, a plurality of membrane modules positioned in the reaction tank, an aeration system, a cleaning system and a sewage pipeline system, n guide plates are arranged in the reaction tank, and the guide plates are arranged at equal intervals and divide the reaction tank into n + 1 reaction areas, the membrane assembly comprises membrane frames located on the two sides of the membrane assembly and hollow fiber membrane filaments located in the middles of the membrane frames. A unique sewage treatment flow direction is formed, the treatment area of unit membrane filaments is increased, the requirement of the system for oxygen can be met through a small membrane area, the treatment effect is greatly improved, only micro-aeration is adopted, the aeration pressure of the air inlet end is smaller than 10 kPa, physical damage caused by high pressure of a membrane assembly does not need to be worried about, and the treatment cost is reduced. A large amount of aeration cost and maintenance cost are saved, meanwhile, a carbon source does not need to be added in the denitrification process, and a large amount of carbon source adding cost is saved.

Description

Technical Field

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

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

[0003] There are still several problems to be solved in the engineering application of this technology in low C / N wastewater treatment.

[0004] (1) Similar to traditional biological water treatment methods, MABR still needs to add a large amount of carbon source to achieve a good denitrification effect when treating low C / N wastewater, which results in a large amount of resource waste.

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

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

[0007] (4) Existing MABR projects may cause membrane blockage, membrane pollution and large biofilm thickness, which will reduce the treatment effect of MABR.

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

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

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

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

[0012] The reaction tank is provided with n guide plates, where n is an integer greater than 1, and the guide plates are arranged at equal intervals and divide the reaction tank into n+1 reaction areas. The guide plates with odd numbers have openings at the top for overflow, and the guide plates with even numbers have openings at the bottom for overflow, so that the sewage forms a continuous Z-shaped flow direction inside the reaction tank, and two upper and lower membrane modules are provided in each reaction area;

[0013] The membrane assembly includes membrane frames located on both sides thereof and hollow fiber membrane filaments located in the middle of the membrane frames, one end of the membrane frame is an air inlet end, and the other end is an air outlet end, the air inlet ends of each membrane frame are located on the same side, and the aeration system is correspondingly arranged above the side;

[0014] The aeration system comprises an air compressor, a main pipeline and n first air inlet pipes, each of which is connected to the membrane assembly provided in each reaction area in a one-to-one correspondence;

[0015] The cleaning system comprises n second air inlet pipes connected to the main pipeline, each end of each second air inlet pipe is connected to a first cleaning nozzle corresponding to the inside of each reaction area, and the bottom of the first cleaning nozzle is connected to a second cleaning nozzle through a conduit;

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

[0017] Furthermore, in each of the reaction areas, the air outlet end of the first cleaning nozzle points to the side where the membrane assembly is located above, and the air outlet end of the second cleaning nozzle points to the side where the membrane assembly is located below. The circulation pipe corresponds to a reaction area at the right end, a circulation pump is provided in the middle of the circulation pipe, and a drain pipe is provided on the upper part of the side wall at the right end of the reaction tank.

[0018] Description: The membrane components are cleaned through the cleaning nozzles and the sewage is circulated through the circulation pipes.

[0019] Furthermore, the lower end of the first air inlet pipe first passes through the air inlet end membrane frame of one of the membrane components located above, and then docks with the air inlet end membrane frame of a membrane component located below. The air inlet end membrane frames corresponding to the two membrane components of the first air inlet pipe are provided with air outlet holes inside, and the air inlet end membrane frame of the membrane component is provided with a plurality of air guide holes inside.

[0020] Description: Air is supplied to the hollow fiber membrane of the membrane assembly through the first air inlet pipe and the air outlet.

[0021] Furthermore, valves are provided on the first air intake pipe and the second air intake pipe.

[0022] Note: The gas injection flow and opening and closing are controlled by valves.

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

[0024] Note: The value of n can be reasonably adjusted according to the size of the reaction pool. The larger the volume of the reaction pool, the larger n is, and the more membrane components are installed. It is suitable for large-scale sewage treatment. When n is 3, 6 groups of membrane components can effectively treat sewage. At the same time, the structure is compact and easy to manage and maintain. By designing the two cleaning nozzles to be movable, the cleaning effect can be improved, and the hydraulic disturbance and airflow impact can be used to achieve uniform cleaning of the biofilm on the hollow fiber membrane.

[0025] Preferably, the top of the first guide plate and the third guide plate are both provided with filter plates, and the inner sides of the tops of the first guide plate and the third guide plate are both provided with slag boxes, the slag boxes are located on the left side of the filter plate, the slag boxes are slidably connected to the internal cavity of the guide plate, the bottom of the cavity is connected to the slide groove, a corrugated plate is provided at the bottom of the slag box, the corrugated plate extends to the bottom of the cavity and is docked with the end of the first cleaning nozzle, and is used to push the corrugated plate to slide up and down by sliding the first cleaning nozzle, and a plurality of cleaning brushes are provided on the top of the slag box, the cleaning brush is fixedly connected to the left side wall of the top of the slag box, and the right side of the cleaning brush is docked with the filter plate for cleaning the filter plate during the up and down sliding process.

[0026] Description: The biofilm residue after cleaning is blocked by the filter plate, and the biofilm residue is scraped and collected by moving the residue box up and down, thereby reducing the impact of biofilm residue on sewage treatment. The residue box can be taken out and cleaned regularly without cleaning it every time the hollow fiber membrane is cleaned, making the entire device easy to maintain and avoiding deposition in the reaction tank.

[0027] Preferably, a spring group is provided at the front and rear sides of the bottom of the slag storage box, and a slider is connected to the end of the spring group. The slider slides up and down inside the limiting grooves provided at the front and rear sides of the cavity.

[0028] Note: The spring group and the slider are arranged to enable the slag storage box to move irregularly in multiple directions, so that the filter plate can be cleaned with a cleaning brush.

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

[0030] Description: The aerobic layer and the anoxic layer are rich in a large number of ammonia oxidizing bacteria, and the anoxic layer is rich in a large number of anaerobic ammonia oxidizing bacteria. + -N) enters from the outside of the biofilm to the inside of the biofilm, and consumes half of the NH4 + -N accumulation corresponding to the amount of NO2 - -N, remaining NH4 + -N and NO2 - -N enters the anaerobic layer and is denitrified by anaerobic ammonia-oxidizing bacteria.

[0031] Furthermore, a mud discharge pipe is provided at the lower part of the side wall at the right end of the reaction tank, and the two sides of the bottom of the membrane frame are fixed by blocks. The block located on the far left is fixed on the inner wall of the reaction tank, and the remaining blocks are fixed on the guide plate. A gap is left between the membrane assembly and the guide plate for the conduit to pass and move.

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

[0033] Furthermore, in one of the reaction areas, an exhaust pipe is provided on the membrane frame at the gas outlet end of the membrane assembly located below, and the exhaust pipe passes through the membrane frame at the gas outlet end of the membrane assembly located above, and exhaust holes are provided inside the membrane frames at the gas outlet ends of the two membrane assemblies corresponding to the exhaust pipe. For each reaction area, the membrane assemblies located above are on the same horizontal line, and the membrane assemblies located below are on the same horizontal line.

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

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

[0036] (1) The composite MABR treatment device for low carbon-nitrogen ratio sewage of the present invention forms a unique sewage treatment flow direction by refining and classifying the membrane component structure, thereby increasing the treatment area per unit membrane fiber. The system's demand for oxygen can be met through a smaller membrane area, greatly improving the treatment effect. In addition, only micro-aeration is used, and the aeration pressure at the air inlet end is less than 10 kPa. There is no need to worry about physical damage caused by high pressure on the membrane component, thus saving a lot of aeration costs and maintenance costs. At the same time, no carbon source needs to be added during the denitrification process, thus saving a lot of carbon source addition costs.

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

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

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

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

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

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

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

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

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

[0046] Fig. 9 This is a schematic diagram of the top structure of a slag storage box of a composite MABR treatment device for low carbon-nitrogen ratio sewage of the present invention;

[0047] Fig.10 This is a schematic diagram of the internal structure of a slag storage box of a composite MABR treatment device for low carbon-nitrogen ratio sewage of the present invention;

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

[0049] Among them, 1-reaction tank, 11-guide plate, 12-chute, 13-filter plate, 14-cavity, 15-limiting groove, 16-mud discharge pipe, 2-membrane assembly, 21-membrane frame, 22-hollow fiber membrane, 23-air guide hole, 24-exhaust pipe, 25-exhaust hole, 26-block, 3-aeration system, 31-air compressor, 32-main line, 33-first air inlet pipe, 34-air outlet, 4-cleaning system, 41-second Inlet pipe, 42-first cleaning nozzle, 43-conduit, 44-second cleaning nozzle, 45-push rod motor, 5-sewage pipe system, 51-water inlet pump, 52-water inlet 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 DESCRIPTION

[0050] Example 1

[0051] like Figure 1 and 2 As 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, an aeration system 3, a cleaning system 4 and a sewage pipe system 5;

[0052] like Figure 3 As shown, three guide plates 11 are arranged inside the reaction tank 1, and each guide plate 11 is arranged at equal intervals and divides the reaction tank 1 into four reaction areas. The guide plates 11 with odd numbers have top openings for overflow, and the guide plates 11 with even numbers have bottom openings for overflow, so that the sewage forms a continuous Z-shaped flow direction inside the reaction tank 1, and two upper and lower membrane modules 2 are arranged in each reaction area;

[0053] like Figures 4 to 7 As shown, the membrane assembly 2 includes a membrane frame 21 located on both sides thereof and a hollow fiber membrane filament 22 located in the middle of the membrane frame 21. One end of the membrane frame 21 is an air inlet end and the other end is an air outlet end. The air inlet ends of the membrane frames 21 are located on the same side, and an aeration system 3 is correspondingly arranged above the side. The hollow fiber membrane filament 22 forms a biofilm 8 after being tamed with aerobic tank activated sludge and anaerobic ammonia oxidation activated sludge. The biofilm 8 is sequentially divided into an aerobic layer 81, an anoxic layer 82 and an anaerobic layer 83 from the inside in a direction away from the hollow fiber aeration membrane. Oxygen layer 83, biofilm 8 is composed of microorganisms, extracellular polymers, bacteria and fungi. In a reaction area, an exhaust pipe 24 is provided on the gas outlet membrane frame 21 of the lower membrane assembly 2, and the upper part of the exhaust pipe 24 passes through the gas outlet membrane frame 21 of the upper membrane assembly 2, and the exhaust pipe 24 is provided with exhaust holes 25 inside the gas outlet membrane frames 21 of the two membrane assemblies 2. For each reaction area, the upper membrane assembly 2 is on the same horizontal line, and the lower membrane assembly 2 is on the same horizontal line;

[0054] Description: The aerobic tank activated sludge and anaerobic ammonia oxidation activated sludge used in the membrane assembly 2 biofilm formation process are from a sewage treatment plant. The sludge acclimation process is as follows: first, use ammonium chloride to prepare a solution containing a certain concentration of ammonia nitrogen, take a certain amount of aerobic layer activated sludge and mix it with an equal amount of the above-mentioned ammonia nitrogen-containing solution and add it to the reaction tank 1, maintain the aeration pressure of the membrane assembly 2 below 10kPa, without inlet and outlet water, set a circulation pump 54 to circulate to ensure that the sludge is in a suspended state, the circulation ratio is 1:1, and the enrichment process of ammonia oxidizing bacteria is carried out. The mud-water mixture in the reaction tank 1 is replaced every two days, and the solution in the reaction tank 1 is taken to determine the concentrations of ammonia nitrogen and nitrite nitrogen. The process lasts for 10 to 15 days. When a biofilm visible to the naked eye is formed on the membrane assembly 2, and the removal rate of ammonia nitrogen and the accumulation rate of nitrite nitrogen are close to 50%, it can be It is considered that the ammonia oxidizing bacteria are successfully enriched, and then the enrichment of anaerobic ammonia oxidizing bacteria is carried out. A certain amount of anaerobic ammonia oxidizing activated sludge is taken, and an equal amount of the above-mentioned ammonia nitrogen-containing solution is mixed and the mud-water mixture is added to the reaction tank 1. The aeration pressure of the membrane component 2 is maintained below 5kPa, and the DO in the reaction tank 1 is maintained below 0.5mg / L. A circulation pump 54 is set to circulate to ensure that the sludge is in a suspended state. The circulation ratio is 1:1, and the enrichment process of anaerobic ammonia oxidizing bacteria is carried out. The mud-water mixture in the reaction tank 1 is replaced every two days, and the solution in the reaction tank 1 is taken to determine the concentrations of TN, ammonia nitrogen, nitrate nitrogen and nitrite nitrogen, and the TN removal in the reaction tank 1 is analyzed. The process lasts for 10 to 15 days. When a biofilm visible to the naked eye is formed on the membrane component 2 and the TN removal rate exceeds 70%, it can be considered that the anaerobic ammonia oxidizing bacteria are successfully enriched.

[0055] The sludge acclimation can form a biofilm 8 visible to the naked eye, the main components of which include microorganisms, extracellular polymers, bacteria and fungi, etc. These components are all derived from aerobic tank activated sludge and anaerobic ammonia oxidation activated sludge. In the membrane assembly 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, so that the biofilm 8 forms an aerobic layer 81, an anoxic layer 82 and an anaerobic layer 83 from the inside in the direction away from the hollow fiber aeration membrane.

[0056] like Figure 2 and 3As shown, the aeration system 3 includes an air compressor 31, a main line 32 and three first air inlet pipes 33. The air compressor 31 is a commercially available product. Each first air inlet pipe 33 is connected to the membrane assembly 2 provided in each reaction area in a one-to-one correspondence. The lower end of the first air inlet pipe 33 first passes through the air inlet end membrane frame 21 of a membrane assembly 2 located above, and then docks with the air inlet end membrane frame 21 of a membrane assembly 2 located below. The first air inlet pipe 33 corresponds to the air inlet end membrane frames 21 of the two membrane assemblies 2. The air inlet end membrane frame 21 of the membrane assembly 2 is provided with a plurality of air guide holes 23. The bottom sides of the membrane frame 21 are fixed by blocks 26. The block 26 located on the far left is fixedly arranged on the inner wall of the reaction tank 1, and the remaining blocks 26 are fixedly arranged on the guide plate 11. A gap is reserved between the membrane assembly 2 and the guide plate 11 for the conduit 43 to pass and move.

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

[0058] like Figure 1 As shown, with the left side as the water inlet end and the right side as the water outlet end, the sewage pipe system 5 includes an inlet pump 51 and an 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 side 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 mud 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 embodiment and the first embodiment is that the first cleaning nozzle 42 and the second cleaning nozzle 44 of the cleaning system 3 are movable, specifically:

[0061] like Figure 3 and 8As shown, the three first cleaning nozzles 42 are respectively located in the slide grooves 12 provided on the left side wall of the reaction pool 1, the right side wall of the first guide plate 11, and the left side wall of the third guide plate 11, and the first cleaning nozzles 42 are all slidably connected with the slide grooves 12. A push rod motor 45 is provided at the inner wall of the front side of the reaction pool 1 corresponding to each first cleaning nozzle 42. 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 to drive the first cleaning nozzle 42 to slide along the slide groove 12 and drive the second cleaning nozzle 44 to move synchronously.

[0062] like Figures 8 to 11 As shown, the top of the first guide plate 11 and the third guide plate 11 are both provided with a filter plate 13, and the inner side of the top of the first guide plate 11 and the third guide plate 11 are both provided with a slag storage box 7, which is located on the left side of the filter plate 13, and the slag storage box 7 is slidably connected to the internal cavity 14 of the guide plate 11, and the bottom of the cavity 14 is connected to the slide groove 12, and a corrugated plate 71 is provided at the bottom of the slag storage box 7, and the corrugated plate 71 extends to the bottom of the cavity 14 and docks with the end of the first cleaning nozzle 42, and is used to push the corrugated plate 71 to slide up and down through the sliding of the first cleaning nozzle 42, and a plurality of cleaning brushes 72 are provided on the top of the slag storage box 7, and the cleaning brush 72 is fixedly connected to the left side wall of the top of the slag storage box 7, and 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, and a spring group 73 is provided on both sides of the bottom of the slag storage box 7, and a slider 74 is connected to the end of the spring group 73, and the slider 74 slides up and down inside the limit groove 15 provided on the front and back sides of the cavity 14.

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

[0064] Open the first cleaning nozzles 42 and the second cleaning nozzles 44 from left to right in sequence, first open the two first cleaning nozzles 42 and the second cleaning nozzles 44 on the far left, open the valve 6 corresponding to the second air inlet pipe 41, so that the first cleaning nozzles 42 and the second cleaning nozzles 44 spray gas, and use hydraulic disturbance and airflow impact to achieve uniform cleaning of the biofilm on the hollow fiber membrane filaments 22, and at the same time start the push rod motor 45 to drive the first cleaning nozzle 42 to slide in the slide groove 12 on the inner wall of the reaction tank 1, and synchronously drive the second cleaning nozzle 44 to move through the guide tube 43, so as to achieve continuous and all-round cleaning of the hollow fiber membrane filaments 22, and the fallen biofilm residues float up with the water flow, are intercepted by the filter plate 13 and retained on the filter plate 13;

[0065] After the cleaning of the first reaction area is completed, the cleaning of the two membrane assemblies 2 in the next reaction area is started. In the same way, the first cleaning nozzle 42 and the second cleaning nozzle 44 are made to spray gas and move. The difference from the previous time is that when the first cleaning nozzle 42 moves, it will push the corrugated plate 71 to move up and down, and the slag storage box 7 will move up and down according to the wavy lines on the corrugated plate 71. At the same time, the cleaning brush 72 will wash the filter plate 13 up and down, scrape the biofilm residue attached to it and drop it into the slag storage box 7;

[0066] On this basis, since there are gaps between each cleaning brush 72 (in order to allow the scraped biofilm residue to 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, the setting of the slider 74 and the spring group 73 just takes advantage of this small displacement, 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 entire slag storage box 7 stable and not dislocated;

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

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

[0069] Example 3

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

[0071] There are two guide plates 11 , and there are also two corresponding first air intake pipes 33 and second air intake pipes 41 .

[0072] Example 4

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

[0074] The number of guide plates 11 is five, and the number of corresponding first air intake pipes 33 and second air intake pipes 41 is also five.

[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 composite MABR: First, the activated sludge from the aerobic tank of the sewage treatment plant is used to domesticate the membrane module 2 in the reaction tank 1 to form microorganisms, thereby achieving the enrichment of ammonia oxidizing bacteria. In this process, the membrane module 2 is micro-aerated through the aeration system 3. Subsequently, the anaerobic ammonium oxidizing activated sludge is used to further domesticate the membrane module 2 to form microorganisms to achieve the enrichment of anaerobic ammonium oxidizing bacteria. In this process, the membrane module 2 is not aerated.

[0078] (2) Operation of the composite MABR system: After the biofilm of ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria was successfully domesticated on the membrane module 2, a normal continuous flow experiment was started to treat low C / N sewage. In the continuous flow experiment, aeration system 3 was used to provide a small amount of aeration to the membrane module 2.

[0079] Among them, in step (1) ammonia oxidizing bacteria biofilm acclimation, the aeration pressure at the air inlet end of the aeration system 3 is lower than 10 kPa, there is no inlet and outlet water, the ratio of sludge to sewage is 1:1, and a circulation pump 54 is set to circulate to ensure that the sludge is in a suspended state, and the circulation ratio is 1:1. The membrane component 2 of the anaerobic ammonia oxidizing bacteria enrichment process is not aerated. The entire microbial biofilm acclimation process lasts for 2 to 4 weeks. The biofilm acclimation effect of ammonia oxidizing bacteria is measured by NO2 - -N accumulation and NH4 + The enrichment of anaerobic ammonia-oxidizing bacteria was measured by the removal of COD and TN and the changes in biofilm 2 observed with the naked eye.

[0080] In step (2), the cleaning system 4 needs to be turned on according to the contamination condition of the membrane assembly 2 or the thickness of the biofilm. The cleaning system 4 cleans the membrane assembly 2 through hydraulic disturbance to make the biofilm thinner.

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

[0082] The aeration pressure (2-10 kPa) at the air inlet end is quantitatively controlled by valve 6, and the aeration pressure gradient at the air inlet end can be controlled to 2 kPa, 4 kPa, 6 kPa, 8 kPa, and 10 kPa.

[0083] The water inlet flow rate is adjusted by adjusting the rotation speed of the water inlet pump 51, thereby quantitatively controlling the hydraulic retention time (4-12h), and the hydraulic retention time gradient can be controlled to 12h, 8h, and 4h.

[0084] The circulation flow rate is adjusted by adjusting the rotation speed of the circulation pump 54, thereby quantitatively controlling the circulation ratio (100-200%), and the circulation ratio gradient can be controlled to 1:1, 2:1.

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

Claims

1. A composite MABR treatment device for low carbon-nitrogen ratio sewage, characterized in that: It comprises a reaction tank (1), a plurality of membrane modules (2) located inside the reaction tank (1), an aeration system (3), a cleaning system (4) and a sewage pipe system (5); The reaction tank (1) is provided with n guide plates (11) inside, n is an integer greater than 1, the guide plates (11) are arranged at equal intervals and divide the reaction tank (1) into n+1 reaction areas, the guide plates (11) with odd numbers have top openings for overflow, and the guide plates (11) with even numbers have bottom openings for overflow, so that the sewage forms a continuous Z-shaped flow direction inside the reaction tank (1), and two upper and lower membrane modules (2) are provided in each reaction area; The membrane assembly (2) comprises membrane frames (21) located on both sides thereof and hollow fiber membranes (22) located in the middle of the membrane frames (21); one end of the membrane frames (21) is an air inlet end and the other end is an air outlet end; the air inlet ends of the membrane frames (21) are located on the same side, and the aeration system (3) is correspondingly arranged above the side; The aeration system (3) comprises an air compressor (31), a main pipeline (32) and n first air inlet pipes (33), each of the first air inlet pipes (33) being connected to the membrane assembly (2) provided in each of the reaction areas in a one-to-one correspondence; The cleaning system (4) comprises n second air inlet pipes (41) connected to the main pipeline (32), the ends of each of the second air inlet pipes (41) corresponding to the interior of each of the reaction areas are connected to a first cleaning nozzle (42), and the bottom of the first cleaning nozzle (42) is connected to a second cleaning nozzle (44) via a conduit (43); With the left side as the water inlet end and the right side as the water outlet end, the sewage pipe system (5) comprises 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 on the top right side of the reaction tank (1).

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

3. A composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that: The lower end of the first air inlet pipe (33) first passes through the air inlet end membrane frame (21) of one of the membrane assemblies (2) located above, and then docks with the air inlet end membrane frame (21) of one of the membrane assemblies (2) located below. The first air inlet pipe (33) is provided with air outlet holes (34) inside the air inlet end membrane frames (21) corresponding to the two membrane assemblies (2), and the air inlet end membrane frames (21) of the membrane assemblies (2) are provided with a plurality of air guide holes (23) inside.

4. A composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that: The first air intake pipe (33) and the second air intake pipe (41) are both provided with valves (6).

5. A composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that: The n is 3, and the three first cleaning nozzles (42) are respectively located in the slide grooves (12) provided on the left side wall of the reaction pool (1), the right side wall of the first guide plate (11), and the left side wall of the third guide plate (11), and the first cleaning nozzles (42) are all slidably connected to the slide grooves (12). A push rod motor (45) is provided at the front inner wall of the reaction pool (1) corresponding to each first cleaning nozzle (42), and 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 slide groove (12) and drive the second cleaning nozzle (44) to move synchronously.

6. A composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 5, characterized in that: The first guide plate (11) and the third guide plate (11) are both provided with a filter plate (13) on the top, and the first guide plate (11) and the third guide plate (11) are both provided with a slag storage box (7) on the inner side of the top, and the slag storage box (7) is located on the left side of the filter plate (13), and the slag storage box (7) is slidably connected to the inner cavity (14) of the guide plate (11), and the bottom of the cavity (14) is connected to the chute (12), and the bottom of the slag storage box (7) is provided with a corrugated plate (71), The corrugated plate (71) extends to the bottom of the cavity (14) and docks with the end of the first cleaning nozzle (42), and is used to push the corrugated plate (71) to slide up and down through the sliding of the first cleaning nozzle (42). A plurality of cleaning brushes (72) are provided on the top of the slag storage box (7), and 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 brush (72) docks with the filter plate (13) and is used to clean the filter plate (13) during the up and down sliding process.

7. A composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 6, characterized in that: A spring group (73) is provided at the front and rear sides of the bottom of the slag storage box (7), and a slider (74) is connected to the end of the spring group (73). The slider (74) slides up and down inside the limiting grooves (15) provided at the front and rear sides of the cavity (14).

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

9. A composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that: A mud discharge pipe (16) is provided at the lower part of the side wall at the right end of the reaction tank (1), and the bottom two sides of the membrane frame (21) are fixed by blocks (26). The block (26) located on the far left is fixed on the inner wall of the reaction tank (1), and the remaining blocks (26) are fixed on the guide plate (11). A gap is left between the membrane assembly (2) and the guide plate (11) for the conduit (43) to pass through and move.

10. A composite MABR treatment device for low carbon-nitrogen ratio sewage according to claim 1, characterized in that: In one of the reaction areas, an exhaust pipe (24) is provided on the outlet membrane frame (21) of the membrane assembly (2) located below, and the exhaust pipe (24) passes through the outlet membrane frame (21) of the membrane assembly (2) located above, and exhaust holes (25) are provided inside the outlet membrane frames (21) of the two membrane assemblies (2) corresponding to the exhaust pipe (24). For each reaction area, the membrane assembly (2) located above is on the same horizontal line, and the membrane assembly (2) located below is on the same horizontal line.

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