A system and method for treating high ammonia-nitrogen wastewater

Abstract

The application discloses a kind of processing high ammonia nitrogen wastewater system and method, including pretreatment device, for high ammonia nitrogen wastewater is settled, flocculation, solid-liquid separation, hydrolysis acidification etc.Pretreatment, remove impurities in water;Anaerobic membrane bioreactor pool is connected to pretreatment device, for the water of hydrolysis acidification pool is anaerobic degradation treatment, the membrane bioreactor pool is placed with immersed ultrafiltration membrane stack;MABR membrane bioreactor membrane pool is connected to anaerobic membrane bioreactor, MABR membrane bioreactor is placed in the MABR reaction pool, for wastewater filtered in anaerobic membrane bioreactor is anoxic degradation and simultaneous nitrification and denitrification process;The application increases membrane bioreactor in anaerobic pool, can improve sludge concentration, reduce energy consumption.The application combines pulse aeration and MABR technology, by MABR gravity and buoyancy effect can be automatically up and down sink and float, and then self-adaptive control MABR biofilm layer thickness, energy saving, efficient, without personnel operation.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically, to an apparatus and method for treating wastewater with high ammonia nitrogen content. Background Technology

[0002] High ammonia nitrogen wastewater refers to wastewater with an ammonia nitrogen content exceeding 50 mg / L, mainly originating from industries such as chemical, pharmaceutical, fertilizer, and aquaculture. Direct discharge of high ammonia nitrogen wastewater into the environment leads to eutrophication of water bodies. High ammonia nitrogen wastewater is characterized by its wide range of sources and significant water quality variations; its discharge into water bodies not only harms aquatic organisms but also seriously endangers drinking water safety. Currently, the main methods for treating high ammonia nitrogen wastewater are physicochemical and biological methods. However, physicochemical methods generally have high operating costs, thus limiting their application. While biological methods offer advantages such as low operating costs and high effluent quality, the acclimatization process of microorganisms is difficult, and microbial activity is easily affected by water quality, water temperature, and toxic substances.

[0003] The MABR (Membrane Aeration Reactor) is a novel water treatment technology that combines membrane separation with biological treatment. It replaces the secondary sedimentation tank in traditional biological treatment processes with a membrane. The membrane can retain activated sludge, and the bioreactor maintains a high concentration of microorganisms, significantly increasing the treatment load. The core components of the MABR include an oxygen-permeable hollow fiber membrane and a biofilm. The biofilm grows on the outer surface of the hollow fiber membrane. Air or pure oxygen is supplied to the biofilm through the hollow fiber membrane. Organic matter, nitrogen, and phosphorus in the wastewater are adsorbed, absorbed, and decomposed by the biofilm (achieving simultaneous nitrification and denitrification), thus purifying the wastewater.

[0004] The thickness and stability of the biofilm significantly impact the performance of MABR (Massively Interactive Bioreactor) systems. An excessively thick biofilm increases mass transfer resistance, while an excessively thin biofilm fails to provide sufficient biomass. However, biofilm growth and shedding are dynamic processes, and effectively controlling biofilm thickness is a crucial challenge for MABR technology. Currently, controlling the biofilm thickness on the surface of the MBAR membrane filaments in MBAR aeration reactors is difficult. The current approach often relies on periodically observing biofilm growth or directly timing aeration to determine when to activate the aeration system. This method is cumbersome and can easily lead to either excessively thick biofilm or insufficient biofilm growth. Furthermore, current MABR technologies often employ continuous aeration, resulting in high energy consumption and requiring manual control. Summary of the Invention

[0005] Technical Problem: The technical problem to be solved by this invention is: an apparatus and method for treating high ammonia nitrogen wastewater, which solves the following problems in the prior art: 1) Traditional simple anaerobic treatment has a low anaerobic sludge growth rate, requiring a high sludge age to maintain sludge activity; 2) High energy consumption caused by continuous aeration; 3) Difficulty in accurately controlling the thickness of MABR biofilm, which may affect the wastewater treatment effect; 4) Complex operation of MABR biofilm thickness control, requiring professional technicians for operation and maintenance.

[0006] Technical Solution: To solve the above-mentioned technical problems, the technical solution adopted in this embodiment of the invention is: a system and method for treating high ammonia nitrogen wastewater, wherein the system includes:

[0007] The pretreatment unit first receives high-ammonia-nitrogen wastewater, which undergoes sedimentation, flocculation, solid-liquid separation, and hydrolysis acidification to remove impurities. The pretreatment unit comprises a sedimentation tank, a flotation tank, a flocculation tank, a solid-liquid separator, and a hydrolysis acidification tank, connected in sequence. The combined use of these devices effectively removes most suspended solids and colloidal substances from the wastewater, providing favorable water quality conditions for subsequent biological treatment.

[0008] An anaerobic membrane bioreactor (ABR) is constructed, containing a submerged ultrafiltration membrane stack. Pretreated wastewater enters the ABR for anaerobic degradation. The ABR is connected to the pretreatment unit and is used to anaerobically degrade the permeate from the hydrolysis acidification tank. During this process, organic matter in the wastewater is converted into methane and carbon dioxide, while total nitrogen is partially removed. The water is then filtered through the submerged ultrafiltration membrane. The submerged ultrafiltration membrane stack uses pulsed aeration, and the pore size of the submerged ultrafiltration membrane is 10-30 nm.

[0009] The MABR membrane bioreactor membrane tank is where anaerobic wastewater enters. Some pollutants undergo anoxic degradation, while the remaining pollutants, including some organic matter, nitrogen, and phosphorus, are adsorbed, absorbed, and decomposed by the biofilm (achieving simultaneous nitrification and denitrification), thus purifying the wastewater. The MABR membrane bioreactor tank is connected to the anaerobic reactor and contains the MABR membrane bioreactor. The MABR membrane bioreactor includes a membrane frame and membrane modules. The membrane frame is cubic and hollow. The upper end of the frame has a MABR membrane air inlet, a MABR membrane exhaust outlet, an aeration inlet, and a fixing pin. The fixing pin is connected to the aeration inlet valve via a control linkage. The MABR membrane air inlet, MABR membrane exhaust outlet, and aeration inlet are sequentially connected to the air inlet hose, exhaust pipe, and aeration inlet pipe, respectively. In addition, the membrane frame is equipped with limiting claws and pulse aeration boxes. The limiting claws are located on both sides of the membrane frame and are used to limit the MABR membrane bioreactor on the guide rail, and can move freely up and down on the guide rail; the pulse aeration box is located below the MABR membrane module and is used for pulse aeration.

[0010] Furthermore, the membrane frame is equipped with a counterweight, and the weight of the counterweight can be calculated according to the required thickness of the biofilm layer, thus adapting to the needs of controlling different biofilm layer thicknesses.

[0011] Furthermore, a crossbeam is provided at the upper end of the membrane frame, and the counterweight is located on the crossbeam to facilitate adjustment of the number and weight of the counterweight.

[0012] Furthermore, the pulse aeration box is located between the two membrane modules and corresponds one-to-one with the MABR membrane module, ensuring that the pulse aeration airflow can wash the membrane fiber surface along the gap between the membrane modules.

[0013] The method includes the following steps:

[0014] Step 1: Pre-sedimentation treatment of high ammonia nitrogen wastewater;

[0015] Step 2: The water produced in Step 1 is treated with air flotation for oil removal.

[0016] Step 3: Perform flocculation and solid-liquid separation treatment on the water produced in step 2;

[0017] Step 4: Anaerobic degradation treatment is carried out on the permeate from step 3, and the permeate is then processed through an anaerobic MBR membrane.

[0018] Step 5 involves introducing the permeate from Step 4 into the membrane tank of the MABR membrane bioreactor. Some pollutants in the water can be degraded in anoxic conditions, while the remaining pollutants, including some organic matter, nitrogen, and phosphorus pollutants, are adsorbed, absorbed, and decomposed by the biofilm (achieving simultaneous nitrification and denitrification), thus purifying the wastewater.

[0019] Furthermore, the MABR membrane bioreactor uses a dense membrane with a thickness of 100-500 nm.

[0020] Furthermore, the wastewater has a residence time of 4-7 hours in the membrane tank of the MABR membrane bioreactor, and the pH value is controlled at 7.5-8.0.

[0021] Traditional anaerobic treatment results in a low anaerobic sludge growth rate, requiring a high sludge age to maintain sludge activity. This invention adds a membrane bioreactor to the anaerobic tank, which can increase sludge concentration, prevent sludge runoff, and features high treatment efficiency, low sludge volume, and low energy consumption, making it suitable for treating high-concentration wastewater.

[0022] When the biofilm layer of the MABR membrane aeration reactor is thicker than a set value, the weight of the MABR membrane aeration reactor is greater than the buoyancy, causing the MABR membrane aeration reactor to sink. The control linkage drives the aeration valve to rotate, opening the aeration valve to perform pulse aeration. When the MABR membrane aeration reactor is in the initial state or the biofilm layer thickness is normal, the weight of the MABR membrane aeration reactor is less than the buoyancy, causing the MABR membrane aeration reactor to float. The control linkage drives the aeration valve to rotate, closing the aeration valve and stopping pulse aeration.

[0023] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The present invention uses a pretreatment device to pretreat high ammonia nitrogen wastewater through sedimentation, flocculation, solid-liquid separation, etc., which can effectively remove impurities in the water and improve the efficiency and quality of subsequent treatment.

[0024] This invention adds a membrane bioreactor to the anaerobic tank, which can increase sludge concentration, increase treatment load, and reduce energy consumption, making it suitable for the treatment of high-concentration wastewater.

[0025] This invention employs an anaerobic membrane bioreactor and a MABR membrane bioreactor membrane tank for secondary treatment, which can effectively degrade ammonia nitrogen in wastewater, resulting in good treatment performance and low operating costs.

[0026] This invention combines pulse aeration with MABR technology. The MABR can automatically rise and fall by gravity and buoyancy, thereby adaptively controlling the thickness of the MABR biofilm layer and achieving a balance between biofilm shedding and growth. Its unique design results in high treatment efficiency and low operation and management costs.

[0027] This invention uses a pulse aeration method, which, compared with the traditional continuous aeration method, reduces aeration energy consumption while allowing for a larger volume, intermittent, and efficient flushing of the biofilm layer on the surface of the MABR membrane fibers.

[0028] This invention combines pulse aeration and MABR technology to more precisely control the thickness of the biofilm, avoiding the problem of poor wastewater treatment effect caused by uneven biofilm thickness, and improving the efficiency and quality of wastewater treatment.

[0029] The present invention has a counterweight on the membrane frame, and the weight of the counterweight to be added can be calculated according to the thickness of the biofilm to be controlled, thereby precisely controlling the thickness of the biofilm layer. Attached Figure Description

[0030] Figure 1 This is an example of an apparatus and method for treating water with high ammonia nitrogen content.

[0031] Figure 2 This is a schematic diagram of the membrane frame in the embodiment.

[0032] Figure 3 This is a schematic diagram of a membrane frame with a pulse aeration box.

[0033] Figure 4 The example shown is a MABR membrane bioreactor.

[0034] Figure 5 This is a schematic diagram of the other side of the membrane frame in the embodiment.

[0035] Figure 6 This is a partial enlarged view of the guide rail limiting block in the embodiment.

[0036] Figure 7 This is a partial schematic diagram of the pulse aeration valve in the closed state.

[0037] Figure 8 This is a partial schematic diagram of the pulse aeration valve in the open state.

[0038] Figure 9 This is a process flow diagram of the system described in this invention.

[0039] The diagram shows: 1. MABR membrane bioreactor; 2. Membrane tank; 3. Guide rail; 4. Guide rail limiting block; 5. MABR membrane air inlet; 6. MABR membrane tail gas outlet; 7. Aeration air inlet; 8. Upper interface of MABR membrane module; 9. Lower interface of MABR membrane module; 10. Counterweight; 11. Limiting claw; 17. Crossbeam; 13. Pulse aeration box; 14. Membrane module; 15. Air inlet hose; 16. Control linkage; 17. Aeration valve; 18. Aeration air inlet pipe; 19. Tail gas exhaust pipe; 20. Fixing pin; 1-1 Sedimentation tank; 1-2. Air flotation tank; 1-3. Flocculation tank; 1-4. Solid-liquid separator; 1-5. Hydrolysis acidification tank; 1-6. Anaerobic membrane bioreactor; 1-7. Submerged ultrafiltration membrane stack; 1-8. Exhaust port; 1-9. MABR membrane bioreactor membrane tank. Detailed Implementation

[0040] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0041] To solve the above-mentioned technical problems, the technical solution adopted in the embodiments of the present invention is as follows: Figure 9

[0042] S1: High-ammonia nitrogen wastewater is introduced into the pretreatment unit. The wastewater first enters sedimentation tank 1-1 and is allowed to settle for 2 hours, allowing large particles to settle. Then, the wastewater enters flotation tank 1-2, where suspended solids and colloidal substances are further removed through flotation. Next, the wastewater enters flocculation tank 1-3, where flocculants are added, causing fine particles to aggregate into larger flocs, facilitating subsequent solid-liquid separation. The wastewater then enters solid-liquid separator 1-4, where filtration removes solid impurities, resulting in clear wastewater. The clarified wastewater then enters hydrolysis acidification tank 1-5 for preliminary hydrolysis.

[0043] S2: The pretreated wastewater is introduced into the anaerobic membrane bioreactor 1-6. The wastewater stays in the anaerobic reactor for 8-15 hours, and the pH value is controlled at 7.0-7.5. Under these conditions, the organic matter in the wastewater is converted into methane and carbon dioxide, and ammonia nitrogen is also partially removed. There is a submerged ultrafiltration membrane stack 1-7 in the anaerobic tank, which can increase the sludge concentration and prevent sludge runoff. It has the characteristics of high treatment efficiency, low sludge volume, and low energy consumption, and is suitable for the treatment of high-concentration wastewater.

[0044] S3: The anaerobic wastewater is introduced into the membrane tank of the MABR membrane bioreactor. The wastewater stays in the MABR membrane bioreactor for 4-7 hours, and the pH value is controlled at 7.5-8.0. Under these conditions, ammonia nitrogen in the wastewater is further removed. The membrane module of the MABR membrane bioreactor is a dense membrane with a thickness of 100-500 nm.

[0045] By following the steps above, high ammonia nitrogen wastewater can be effectively treated, while also reducing equipment investment and operational management complexity, and achieving ideal treatment results in a relatively short time.

[0046] A method for treating water with high ammonia nitrogen content, comprising a system including:

[0047] The pretreatment device includes a sedimentation tank, an air flotation tank, a flocculation tank, a solid-liquid separator, and a hydrolysis acidification tank connected in sequence. By using these devices in combination, most of the suspended solids and colloidal substances in the wastewater can be effectively removed, providing good water quality conditions for subsequent biological treatment.

[0048] An anaerobic membrane bioreactor, containing a submerged ultrafiltration membrane stack, is connected to a pretreatment unit for anaerobic degradation treatment of hydrolyzed and acidified wastewater. The anaerobic-treated wastewater is then filtered through a submerged ultrafiltration membrane. The submerged ultrafiltration membrane stack uses pulsed aeration, and the pore size of the submerged ultrafiltration membrane is 10-30 nm.

[0049] MABR membrane bioreactor membrane tanks 1-9 are connected to the anaerobic reactor and contain MABR membrane bioreactor 1. Each MABR membrane bioreactor membrane tank includes: MABR membrane bioreactor 1, membrane tank 2, and guide rail 3. The MABR membrane bioreactor 1 is movably confined on the guide rail 3, and a guide rail limiting block 4 is provided at the upper end of the guide rail.

[0050] The MABR membrane bioreactor 1 includes a membrane frame and a membrane module 14. The membrane module is composed of several MABR hollow fiber membrane filaments with both ends glued into the membrane shell. The membrane frame is a cubic and hollow structure, or more specifically a rectangular hollow structure. The upper end of the membrane frame is provided with a MABR membrane air inlet 5 connected to an air inlet hose 15 for supplying gas to the MABR membrane module.

[0051] The upper end of the membrane frame is provided with a MABR membrane exhaust outlet 6, which is connected to the exhaust pipe 19 to remove the gas originally present in the MABR membrane fibers.

[0052] The upper end of the membrane frame is also equipped with a fixing pin 20 and an aeration inlet 7. The fixing pin 20 is connected to the valve of the aeration inlet valve 17 through the control link 16. The aeration inlet 7 is connected to the aeration inlet pipe 18. When the biofilm layer of the MABR membrane aeration reactor is thicker than the set value, the weight of the MABR membrane aeration reactor is greater than the buoyancy, and the MABR membrane aeration reactor sinks. The control link drives the aeration valve to rotate, and the aeration valve opens to perform pulse aeration. When the MABR membrane aeration reactor is in the initial state or the biofilm layer thickness is normal, the weight of the MABR membrane aeration reactor is less than the buoyancy, and the MABR membrane aeration reactor floats. The control link drives the aeration valve to rotate, and the aeration valve closes to stop pulse aeration.

[0053] The upper end of the membrane frame is also provided with an upper interface 8 for the MABR membrane module, which is used to fix the upper end of the MABR membrane module, and the lower end of the membrane frame is provided with a lower interface 9 for the MABR membrane module, which is used to fix the lower end of the MABR membrane module.

[0054] A pulse aeration box 13 is provided at the lower end of the membrane frame, located below the MABR membrane module, for pulse aeration.

[0055] The crossbeam corresponding to the membrane frame is provided with limiting claws 11, a total of 4, corresponding to each other on both sides of the membrane frame, used to limit the membrane frame to the guide rail 3. The diameter of the limiting claws 11 is smaller than the diameter of the guide rail 3, so that the MABR membrane aeration reactor 1 can float freely on the guide rail 3.

[0056] Furthermore, the membrane frame is provided with a counterweight 10, and the weight of the counterweight can be calculated according to the thickness of the biofilm layer to be controlled, thereby adapting to the needs of controlling different biofilm layer thicknesses.

[0057] Furthermore, the upper end of the membrane frame is provided with a crossbeam 17, and the counterweight 10 is provided on the crossbeam 17. There can be multiple counterweights 10, which are evenly distributed on the crossbeam 17. By placing the counterweights 10 on the upper end of the membrane frame crossbeam, it is convenient to adjust the number and weight of the counterweights to meet the requirements of different biofilm layer thicknesses.

[0058] Furthermore, the pulse aeration box 13 is located between the two membrane modules and corresponds one-to-one with the MABR membrane module, ensuring that the pulse aeration airflow can wash the membrane fiber surface along the gap between the membrane modules.

[0059] Usage: Calculate the weight of the counterweights to be added based on the desired thickness of the MABR biofilm, and then proceed accordingly. Figure 1 The method involves installing the MABR membrane bioreactor inside the membrane tank, opening the inlet hose and exhaust valve to introduce the required gas into the membrane module, and expelling the existing gas from the membrane module. When the membrane stack is in its initial state or the biofilm is in its normal state, the weight of the MABR reactor is less than the buoyancy, and the membrane module is in a floating state. Figure 7 At this time, the aeration inlet valve is closed under the action of the control linkage. As the thickness of the MABR biofilm increases, the weight of the MABR membrane bioreactor continuously increases. When the weight of the MABR membrane bioreactor exceeds its own buoyancy, such as... Figure 8 At this time, the aeration inlet valve is in the open state under the action of the control linkage, and pulse aeration washes the surface of the MABR membrane. As the thickness of the biofilm layer decreases, the weight of the MABR reactor decreases. When the weight of the MABR reactor is less than the buoyancy, the MABR reactor floats up again, and the aeration valve closes again under the action of the control linkage, thereby controlling the thickness of the biofilm.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the specific embodiments described above. The specific embodiments and descriptions in the specification are merely for further illustrating the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. A system for treating high ammonia nitrogen wastewater, characterized in that, include: The pretreatment device is used to pretreat high ammonia nitrogen wastewater by sedimentation, flocculation, solid-liquid separation, hydrolysis and acidification to remove impurities from the water. An anaerobic membrane bioreactor, connected to a pretreatment device, is used to anaerobically degrade the permeate from a hydrolysis acidification tank. The membrane bioreactor contains a submerged ultrafiltration membrane stack. The MABR membrane bioreactor membrane tank is connected to the anaerobic membrane bioreactor. The MABR membrane bioreactor membrane tank contains the MABR membrane bioreactor, which is used to perform anoxic degradation and simultaneous nitrification and denitrification processes on the wastewater filtered from the anaerobic membrane bioreactor. The pretreatment device includes a sedimentation tank, an air flotation tank, a flocculation tank, a solid-liquid separator, and a hydrolysis acidification tank connected in sequence. The MABR membrane bioreactor membrane tank includes: a MABR membrane bioreactor, a membrane tank, and a guide rail. The MABR membrane bioreactor is confined on the guide rail and can move on the guide rail. A guide rail limiting block is provided at the upper end of the guide rail. The MABR membrane bioreactor includes a membrane frame and a membrane module. The membrane frame is a cubic and hollow structure. The upper end of the membrane frame is provided with a MABR membrane air inlet, a MABR membrane exhaust outlet, an aeration air inlet, and a fixing pin. The fixing pin is connected to the valve of the aeration air inlet valve through a control linkage. The MABR membrane air inlet, MABR membrane exhaust outlet, and aeration air inlet are connected to the air inlet hose, exhaust pipe, and aeration air inlet pipe in sequence, respectively. The membrane frame is also equipped with limiting claws and pulse aeration boxes. The limiting claws are located on both sides of the membrane frame and are used to limit the MABR membrane bioreactor on the guide rail, and can move freely up and down on the guide rail. The pulse aeration box is located below the MABR membrane module and is used for pulse aeration. The membrane frame is equipped with a counterweight. The weight of the counterweight is calculated according to the thickness of the biofilm layer to be controlled, so as to meet the needs of controlling different biofilm layer thicknesses. The pulse aeration box is located between the two membrane modules and corresponds one-to-one with the MABR membrane module, ensuring that the pulse aeration airflow can wash the membrane fiber surface along the gap between the membrane modules. When the biofilm layer of the MABR membrane aeration reactor is thicker than the set value, the weight of the MABR membrane aeration reactor is greater than the buoyancy, and the MABR membrane aeration reactor sinks. The control linkage drives the aeration valve to rotate, and the aeration valve opens to perform pulse aeration. When the MABR membrane aeration reactor is in the initial state or the biofilm layer thickness is normal, the weight of the MABR membrane aeration reactor is less than the buoyancy, and the MABR membrane aeration reactor floats. The control linkage drives the aeration valve to rotate, and the aeration valve closes, stopping pulse aeration.

2. A system for treating high ammonia nitrogen wastewater according to claim 1, characterized in that, The MABR membrane bioreactor uses a dense membrane with a thickness of 100-500 nm.

3. A system for treating high ammonia nitrogen wastewater according to claim 1, characterized in that, The submerged ultrafiltration membrane stack uses pulse aeration.

4. A system for treating high ammonia nitrogen wastewater according to claim 1, characterized in that, The pore size of the submerged ultrafiltration membrane is 10-30 nm.

5. A method for treating wastewater with high ammonia nitrogen content, characterized in that, Using the system described in claim 1, The method includes the following steps: Step 1: Pre-sedimentation treatment of high ammonia nitrogen wastewater; Step 2: The water produced in Step 1 is treated with air flotation for oil removal. Step 3 involves flocculation, solid-liquid separation, and hydrolysis acidification treatment of the water produced in step 2. Step 4: Anaerobic treatment is performed on the permeate from step 3, and the permeate is filtered through a submerged ultrafiltration membrane. Step 5 involves introducing the permeate from Step 4 into the membrane tank of the MABR membrane bioreactor, where some pollutants in the water undergo anoxic degradation, and the remaining pollutants, including some organic matter, nitrogen, and phosphorus pollutants, are adsorbed, absorbed, and decomposed by the biofilm, achieving simultaneous nitrification and denitrification, thus purifying the wastewater.

6. A method for treating high ammonia nitrogen wastewater according to claim 5, characterized in that, The wastewater has a residence time of 4-7 hours in the membrane tank of the MABR membrane bioreactor, and the pH value is controlled at 7.5-8.0.

Images