Coal gasification wastewater membrane absorption deamination system

Abstract

The utility model discloses a coal gasification wastewater membrane absorption deamination system, including the pretreatment filtration system, alkali adding and PH adjusting system, raw water pump, heat exchange system, ammonia nitrogen wastewater membrane absorption device that connect gradually, the inlet of pretreatment filtration system connects ammonia nitrogen wastewater, and ammonia nitrogen wastewater membrane absorption device has sulphuric acid entrance and wastewater entrance, and ammonia nitrogen wastewater membrane absorption device has deamination wastewater outlet and ammonium salt export, and deamination wastewater outlet connects water production pH buffer device, and the inlet of water production pH buffer device is connected with buffer agent and is put into pipe, and ammonium salt export connects the resource utilization recovery system, and alkali adding and PH adjusting system includes lye tank, raw water tank, and lye tank passes through valve, lye pump and connects raw water tank, and raw water tank is installed between pretreatment filtration system, raw water pump, and install first pH meter in raw water tank. The utility model discloses adopt the land area of membrane method deamination to be small, and the whole process is closed and does not produce secondary pollution, and it is not easy to scale and does not consume steam.

Description

Technical Field

[0001] This utility model relates to the field of wastewater ammonia removal, and in particular to a membrane absorption ammonia removal system for coal gasification wastewater. Background Technology

[0002] Coal gasification is widely used in coal gasification, ammonia synthesis, coal-fired power generation, and the production of various coal-based chemicals and coal-based low-carbon olefins, and is one of the core technologies of coal chemical industry. Due to the characteristics of the process, the crude coal gas produced during coal gasification generates a large amount of coal gasification wastewater during the rapid cooling and washing process. The wastewater contains ammonia nitrogen, sulfides, cyanides, etc., and if it is discharged directly without treatment, it will cause serious environmental pollution.

[0003] The on-site sample of ammonia-nitrogen-containing wastewater from a similar project's coal gasification is shown in the figure. The main color is black (containing a large number of fine coal ash particles), and it also has a distinct pungent ammonia odor.

[0004] In traditional stripping processes, high-ammonia nitrogen wastewater, after alkali dissociation, first enters a stripping tower where a large amount of compressed air is used for stripping. This stripping generates a large amount of ammonia-containing tail gas, which needs to enter an acid absorption tower to absorb the ammonia and prevent it from polluting the atmosphere. However, stripping towers require a large footprint and the use of air stripping may cause secondary pollution.

[0005] Besides the stripping process, there is also the traditional ammonia stripping process, specifically the coal gasification high-ammonia nitrogen wastewater stripping unit. In this process, gasification wastewater from the coal gasification stage is pumped up and thoroughly mixed with alkali solution pumped from the alkali solution pump. After pH adjustment, it enters the stripping ammonia removal tower along with heat source steam. On the tower plates, mass and heat transfer occur between the wastewater and the stripping solution. Inside the tower, dissolved NH3 is desorbed and rises to the top of the tower as a gas. It then undergoes gas-liquid separation in a condenser, ultimately forming ammonia water. The gasified wastewater, after evaporation and stripping, proceeds to the next stage of treatment. However, due to the influence of other potential anions, such as sulfate and chloride ions, this process has limitations in reducing ammonia nitrogen. Even with a large amount of steam, it is impossible to reduce the ammonia nitrogen concentration in the purified water to an absolutely low level. Under normal conditions, the system's ammonia nitrogen removal efficiency is around 98%, unable to consistently reach 99% or higher. Meanwhile, when the required ammonia concentration in the effluent is below 100 mg / L, it often requires significantly more steam energy to be consumed.

[0006] Furthermore, traditional ammonia stripping processes may have the following problems:

[0007] 1. Scaling Issues: The main problem is scaling on the stripping tower trays. Due to the high hardness of the gasification wastewater, the CaCO3 and MgCO3 generated after adding alkali adhere to the sieve trays, gradually shrinking the tray pores. Additionally, depending on the process layout, other issues may arise such as clogging of the alkali mixer and scaling on the wastewater heater.

[0008] 2. High steam consumption: The material needs to be heated to reach its boiling point and the heat required to overcome the latent heat of vaporization, so the steam consumption is relatively high.

[0009] Therefore, traditional ammonia stripping processes are not suitable for ammonia removal from coal gasification wastewater. Utility Model Content

[0010] To overcome the above-mentioned shortcomings, the purpose of this utility model is to provide a membrane absorption ammonia removal system for coal gasification wastewater that uses membrane technology, has a small footprint, is fully enclosed and does not generate secondary pollution, is not prone to scaling, and does not consume steam.

[0011] To achieve the above objectives, one technical solution adopted by this utility model is: a coal gasification wastewater membrane absorption ammonia removal system, comprising a pretreatment filtration system, an alkali addition and pH adjustment system, a raw water pump, a heat exchange system, and an ammonia nitrogen wastewater membrane absorption device connected in sequence. The inlet of the pretreatment filtration system is connected to ammonia nitrogen wastewater. The ammonia nitrogen wastewater membrane absorption device has a sulfuric acid inlet and a wastewater inlet. The ammonia nitrogen wastewater membrane absorption device has an ammonia removal wastewater outlet and an ammonium salt outlet. The ammonia removal wastewater outlet is connected to a product water pH buffer device. The inlet of the product water pH buffer device is connected to a buffer additive pipe. The ammonium salt outlet is connected to a resource utilization and recovery system. The alkali addition and pH adjustment system includes an alkali tank and a raw water tank. The alkali tank is connected to the raw water tank through a valve and an alkali pump. The raw water tank is installed between the pretreatment filtration system and the raw water pump. A first pH meter is installed inside the raw water tank.

[0012] The beneficial effects of this utility model's membrane absorption ammonia removal system for coal gasification wastewater are that, compared to traditional stripping and ammonia stripping processes, its core advantages are high ammonia removal efficiency, low energy consumption, no secondary pollution, and the ability to recover ammonia nitrogen resources. It specifically addresses the problems of high energy consumption, heavy pollution, and difficulty in ammonia nitrogen recovery inherent in traditional processes. In this application, ammonia is directionally absorbed by the acid solution with almost no escape, resulting in high ammonia removal efficiency. Only a power pump and low-temperature heat exchange are required, eliminating the need for large amounts of steam or fans, thus reducing energy consumption. Ammonia is absorbed as ammonium salts, with no ammonia-containing tail gas emissions, preventing secondary pollution. High-purity ammonium salts (such as ammonium sulfate) are directly produced and can be used as a product for resource recovery.

[0013] Preferably, the sulfuric acid inlet is connected to an acid circulation system, which includes a dilute sulfuric acid storage tank, a sulfuric acid circulation tank, a sulfuric acid pump, and a sulfuric acid safety filter connected in sequence. The sulfuric acid safety filter is connected to the sulfuric acid inlet. The ammonia nitrogen wastewater membrane absorption device has an acid outlet, which is connected to the sulfuric acid circulation tank. A second pH meter is installed on the sulfuric acid circulation tank. The acid circulation system continuously and stably provides qualified dilute sulfuric acid absorbent to the membrane absorption unit. Through recycling and pH monitoring, it ensures the ammonia nitrogen absorption efficiency while protecting the membrane modules and circulation equipment. The dilute sulfuric acid storage tank serves as a fresh supply of dilute sulfuric acid to replenish the acid consumed in the circulation system. The acid in the sulfuric acid circulation tank consists of two parts: one part receives dilute sulfuric acid returned from the membrane absorption unit that has already absorbed some ammonia, and the other part receives fresh acid replenished from the dilute sulfuric acid storage tank, achieving acid mixing and temporary storage. The sulfuric acid security filter is used to filter out tiny impurities and crystalline particles (such as generated ammonium sulfate microcrystals) in the circulating acid, preventing them from entering the membrane absorption unit and clogging the membrane pores or scratching the membrane surface, thus protecting the membrane modules. The second pH meter is used to monitor the pH value, which can determine whether the current acid absorption capacity is sufficient. Through pH monitoring, the timing of acid replenishment can be precisely controlled, avoiding waste caused by premature acid replenishment and incomplete ammonia nitrogen absorption caused by premature acid replenishment.

[0014] Preferably, the resource utilization and recycling system includes an ammonium salt recovery tank, an ammonium salt recovery pump, and a low-temperature concentration and crystallization device connected in sequence. The ammonium salt recovery tank temporarily stores the dilute ammonium salt solution discharged from the membrane absorption device, acting as a buffer and regulator to balance the difference between the discharge rate of the membrane absorption device and the delivery rate of subsequent pumps, preventing the operation of subsequent equipment from being affected by unstable feed. The ammonium salt recovery pump pressurizes and transports the ammonium salt solution in the ammonium salt recovery tank to the low-temperature concentration and crystallization device. The low-temperature concentration and crystallization device concentrates the dilute ammonium salt solution and precipitates solid ammonium salt crystals. The low-temperature environment prevents the ammonium salt from decomposing at high temperatures, while reducing energy consumption, ensuring product purity, and converting the ammonium salt into a high-purity ammonium salt product, thus achieving resource utilization. The produced ammonium salt product can be sold externally, offsetting part of the wastewater treatment costs and improving the overall economic efficiency of the process. Compared with traditional high-temperature evaporation, the low-temperature concentration process significantly reduces energy consumption.

[0015] Preferably, the ammonia nitrogen wastewater membrane absorption device is connected to a cleaning system. The cleaning system includes a solution tank, a chemical cleaning pump, and a cleaning security filter connected in sequence. A cleaning solution flows through the solution tank. The ammonia nitrogen wastewater membrane absorption device has a cleaning inlet and a cleaning outlet. The cleaning security filter is connected to the cleaning inlet, and the cleaning outlet is connected to the solution tank. This invention allows for periodic cleaning of the ammonia nitrogen wastewater membrane absorption device when it is not in use.

[0016] Preferably, the ammonia nitrogen wastewater membrane absorption device uses a PTFE hollow fiber membrane. The PTFE hollow fiber membrane is porous but not wetted by water or absorbent (hydrophobic properties). Wastewater flows on one side of the membrane, while the absorbent (such as dilute sulfuric acid) flows on the other side. Ammonia gas can diffuse from the aqueous phase to the absorbent phase through the membrane's micropores, achieving "contact without mixing" between the gas and liquid phases, maximizing the mass transfer area, and thus forming a highly efficient mass transfer interface. PTFE material has the characteristics of acid and alkali resistance, high temperature resistance, and chemical corrosion resistance, and can adapt to ammonia nitrogen wastewater in high pH, ​​high temperature, and complex pollutant environments, avoiding damage to the membrane material.

[0017] Preferably, the pretreatment filtration system includes a quartz sand filter, a security filter, and an ultrafilter connected in sequence. The quartz sand filter mainly removes large particles of coal dust, ash, and suspended solids from the wastewater, reducing the turbidity of the wastewater through the interception, sedimentation, and adsorption of quartz sand particles. The security filter removes fine coal dust particles and tiny suspended solids that are not intercepted by the quartz sand filter, typically with a filtration accuracy of 1-5 microns, protecting the subsequent ultrafiltration membrane and preventing large particles from scratching or clogging the membrane module. The ultrafilter is used to deeply remove colloids, emulsified oil, some tar-like macromolecular organic matter, and bacteria from the wastewater, with a filtration accuracy of up to 0.01 microns.

[0018] Preferably, the ammonia nitrogen wastewater is the effluent from ammonia nitrogen-containing wastewater after stripping and ammonia removal, wherein the ammonia nitrogen content is 100 mg / L.

[0019] Preferably, at least two ammonia nitrogen wastewater membrane absorption devices are provided, and the at least two ammonia nitrogen wastewater membrane absorption devices are arranged in parallel. When one ammonia nitrogen wastewater membrane absorption device is in use, the PTFE hollow fiber membrane of the other ammonia nitrogen wastewater membrane absorption device can be flushed. Attached Figure Description

[0020] Figure 1 This is a simplified diagram of the PTFE hollow fiber membrane absorption process of the ammonia nitrogen wastewater membrane absorption device in this embodiment;

[0021] Figure 2 This is a system block diagram of this embodiment;

[0022] Figure 3 This is a system block diagram of the alkali-addition pH adjustment system in this embodiment;

[0023] Figure 4 This is a system block diagram of the acid cycle system in this embodiment;

[0024] Figure 5 This is a system block diagram combining the acid cycle system and the resource utilization and recycling system in this embodiment;

[0025] Figure 6This is a system block diagram of the cleaning system in this embodiment.

[0026] In the picture:

[0027] 1. Pretreatment filtration system; 1a. Quartz sand filter; 1b. Security filter; 1c. Ultrafiltration unit; 2. Alkali addition and pH adjustment system; 2a. Alkali tank; 2b. Raw water tank; 2c. Valves; 2d. Alkali pump; 2e. First pH meter; 3. Raw water pump; 4. Heat exchange system; 5. Ammonia nitrogen wastewater membrane absorption device; 6. Product water pH buffer device; 7. Acid circulation system; 7a. Dilute sulfuric acid storage tank; 7b. Sulfuric acid circulation tank; 7c. Sulfuric acid pump; 7d. Sulfuric acid security filter; 7e. Second pH meter; 8. Resource utilization and recovery system; 8a. Ammonium salt recovery tank; 8b. Ammonium salt recovery pump; 8c. Low temperature concentration and crystallization equipment; 9. Cleaning system; 9a. Solution tank; 9b. Chemical cleaning pump; 9c. Cleaning security filter. Detailed Implementation

[0028] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention.

[0029] See Figures 1 to 6 As shown, this embodiment discloses a coal gasification wastewater membrane absorption ammonia removal system, including a pretreatment filtration system 1, an alkali addition and pH adjustment system 2, a raw water pump 3, a heat exchange system 4, and an ammonia nitrogen wastewater membrane absorption device 5 connected in sequence. The inlet of the pretreatment filtration system 1 is connected to ammonia nitrogen wastewater. The ammonia nitrogen wastewater membrane absorption device 5 uses a PTFE hollow fiber membrane and has a sulfuric acid inlet and a wastewater inlet. The ammonia nitrogen wastewater membrane absorption device 5 has an ammonia removal wastewater outlet and an ammonium salt outlet. The ammonia removal wastewater outlet is connected to a product water pH buffer device 6 to stabilize the product water pH at 6-8. The pH range is neutral. The inlet of the product water pH buffer device 6 is connected to a buffer addition pipe, and the ammonium salt outlet is connected to the resource utilization and recovery system 8. The alkali addition pH adjustment system 2 includes an alkali tank 2a and a raw water tank 2b. The alkali tank 2a is connected to the raw water tank 2b through a valve 2c and an alkali pump 2d. The raw water tank 2b is installed between the pretreatment filtration system 1 and the raw water pump 3. The first pH meter 2e is installed in the raw water tank 2b.

[0030] The core working principle of this system is a closed-loop process of pretreatment, pH adjustment, membrane absorption, post-treatment, and resource recovery. It converts ammonia nitrogen in coal gasification wastewater into high-purity ammonium salts. The first pH meter 2e is a key monitoring element for precise pH adjustment and ensuring membrane absorption efficiency. It efficiently removes ammonia, eliminates secondary pollution, and achieves resource recovery, while maintaining stable operation and controllable costs. The coal gasification wastewater first enters the pretreatment filtration system 1 to remove impurities such as coal dust, suspended solids, and colloids. In the alkali addition and pH adjustment system 2, the wastewater enters the raw water tank 2b. A 32% sodium hydroxide solution from the alkali tank 2a is injected into the raw water tank 2b through valve 2c and alkali pump 2d. The first pH meter 2e monitors the pH value of the wastewater in the tank in real time. When the pH reaches the set alkaline range (usually 10-12), the alkali pump 2d stops adding alkali. At this point, the ammonium ions (NH4⁺) in the wastewater are converted into volatile ammonia gas (NH3). The raw water pump 3 then completes the pH adjustment. The alkaline wastewater is pressurized and transported to the heat exchange system 4 to adjust the wastewater temperature to the appropriate range for membrane absorption (30-40℃), thereby improving the volatilization and diffusion efficiency of ammonia. The adjusted wastewater enters the ammonia nitrogen wastewater membrane absorption device 5, while dilute sulfuric acid enters the device through the sulfuric acid inlet. Inside the membrane module, ammonia on the wastewater side diffuses through the membrane pores to the sulfuric acid side, reacting with the dilute sulfuric acid to generate ammonium sulfate ((NH4)2SO4), thus achieving ammonia nitrogen removal. The ammonia-removed wastewater enters the product water pH buffer device 6 from the ammonia-removed wastewater outlet, where acidic buffer is added through the buffer inlet pipe to adjust the pH to the neutral range of 6-8, achieving the discharge standard. The generated ammonium sulfate solution enters the resource utilization and recovery system 8 from the ammonium salt outlet, where it is concentrated and crystallized to obtain high-purity solid ammonium salt, realizing the resource utilization of ammonia nitrogen.

[0031] The sulfuric acid inlet is connected to an acid circulation system 7, which includes a dilute sulfuric acid storage tank 7a, a sulfuric acid circulation tank 7b, a sulfuric acid pump 7c, and a sulfuric acid security filter 7d connected in sequence. The sulfuric acid security filter 7d is connected to the sulfuric acid inlet. The ammonia nitrogen wastewater membrane absorption device 5 has an acid outlet, which is connected to the sulfuric acid circulation tank 7b. A second pH meter 7e is installed on the sulfuric acid circulation tank 7b. The acid circulation system 7 continuously and stably provides qualified dilute sulfuric acid absorbent to the membrane absorption unit. Through recycling and pH monitoring, it ensures the ammonia nitrogen absorption efficiency while protecting the membrane modules and circulation equipment. The dilute sulfuric acid storage tank 7a serves as a fresh dilute sulfuric acid tank to replenish the acid consumed in the circulation system. The acid in the sulfuric acid circulation tank 7b consists of dilute sulfuric acid returned from the membrane absorption unit that has already absorbed some ammonia, and fresh acid replenished from the dilute sulfuric acid storage tank 7a, achieving acid mixing and temporary storage. The sulfuric acid security filter 7d filters out tiny impurities and crystalline particles in the circulating acid, such as the generated ammonium sulfate microcrystals, preventing them from entering the membrane absorption unit and clogging the membrane pores or scratching the membrane surface, thus protecting the membrane modules. The second pH meter 7e monitors the pH value online, determining whether the current acid absorption capacity is sufficient. Through pH monitoring, the timing of acid replenishment can be precisely controlled, avoiding waste caused by premature acid replenishment and incomplete ammonia nitrogen absorption caused by premature acid replenishment.

[0032] The resource utilization and recycling system 8 of this embodiment includes an ammonium salt recovery tank 8a, an ammonium salt recovery pump 8b, and a low-temperature concentration and crystallization device 8c connected in sequence. The ammonium salt recovery tank 8a is used to temporarily store the dilute ammonium salt solution discharged from the membrane absorption device. The ammonium salt recovery pump 8b then pressurizes and transports the ammonium salt solution in the ammonium salt recovery tank 8a to the low-temperature concentration and crystallization device 8c, where the dilute ammonium salt solution is concentrated and solid ammonium salt crystals are precipitated for resource utilization. The produced ammonium salt product can be sold externally.

[0033] The ammonia nitrogen wastewater membrane absorption device 5 is connected to the cleaning system 9. The cleaning system 9 includes a solution tank 9a, a chemical cleaning pump 9b, and a cleaning security filter 9c connected in sequence. The solution tank 9a is filled with a cleaning solution. The ammonia nitrogen wastewater membrane absorption device 5 has a cleaning inlet and a cleaning outlet. The cleaning security filter 9c is connected to the cleaning inlet, and the cleaning outlet is connected to the solution tank 9a. When the cleaning system 9 is in use, the ammonia nitrogen wastewater membrane absorption device 5 does not perform ammonia removal operations. A switching switch is required to activate either the cleaning mode or the ammonia removal mode.

[0034] The pretreatment filtration system 1 in this embodiment includes a quartz sand filter 1a, a security filter 1b, and an ultrafiltration unit 1c connected in sequence. The ammonia nitrogen wastewater is the effluent after stripping and deammoniation of ammonia nitrogen-containing wastewater, wherein the ammonia nitrogen content is 100 mg / L. It first passes through the quartz sand filter 1a to remove large particles of coal dust, ash, and suspended solids in the wastewater. Then it passes through the security filter 1b to remove fine coal dust particles and tiny suspended solids that were not intercepted by the quartz sand filter 1a. Finally, it passes through the ultrafiltration unit 1c to deeply remove colloids, emulsified oil, some tar-like macromolecular organic matter, and bacteria from the wastewater, with a filtration accuracy of up to 0.01 microns.

[0035] At least two ammonia nitrogen wastewater membrane absorption devices 5 are provided, and the at least two ammonia nitrogen wastewater membrane absorption devices 5 are arranged in parallel. When one ammonia nitrogen wastewater membrane absorption device 5 is in use, the PTFE hollow fiber membrane of the other ammonia nitrogen wastewater membrane absorption device 5 can be flushed.

[0036] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it. They cannot be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A membrane absorption ammonia removal system for coal gasification wastewater, characterized in that: The system includes a pretreatment filtration system (1), an alkali addition and pH adjustment system (2), a raw water pump (3), a heat exchange system (4), and an ammonia nitrogen wastewater membrane absorption device (5) connected in sequence. The inlet of the pretreatment filtration system (1) is connected to ammonia nitrogen wastewater. The ammonia nitrogen wastewater membrane absorption device (5) has a sulfuric acid inlet and a wastewater inlet. The ammonia nitrogen wastewater membrane absorption device (5) has a deammoniation wastewater outlet and an ammonium salt outlet. The deammoniation wastewater outlet is connected to a product water pH buffer device (6). The inlet of the product water pH buffer device (6) is connected to a buffer injection pipe. The ammonium salt outlet is connected to a resource utilization and recovery system (8). The alkali addition and pH adjustment system (2) includes an alkali tank (2a) and a raw water tank (2b). The alkali tank (2a) is connected to the raw water tank (2b) through a valve (2c) and an alkali pump (2d). The raw water tank (2b) is installed between the pretreatment filtration system (1) and the raw water pump (3). A first pH meter (2e) is installed in the raw water tank (2b).

2. The coal gasification wastewater membrane absorption ammonia removal system according to claim 1, characterized in that: The sulfuric acid inlet is connected to an acid circulation system (7), which includes a dilute sulfuric acid storage tank (7a), a sulfuric acid circulation tank (7b), a sulfuric acid pump (7c), and a sulfuric acid security filter (7d) connected in sequence. The sulfuric acid security filter (7d) is connected to the sulfuric acid inlet. The ammonia nitrogen wastewater membrane absorption device (5) has an acid outlet, which is connected to the sulfuric acid circulation tank (7b). A second pH meter (7e) is installed on the sulfuric acid circulation tank (7b).

3. The membrane absorption ammonia removal system for coal gasification wastewater according to claim 1, characterized in that: The resource utilization and recycling system (8) includes an ammonium salt recovery tank (8a), an ammonium salt recovery pump (8b), and a low-temperature concentration and crystallization device (8c) connected in sequence.

4. The membrane absorption ammonia removal system for coal gasification wastewater according to claim 1, characterized in that: The ammonia nitrogen wastewater membrane absorption device (5) is connected to the cleaning system (9). The cleaning system (9) includes a solution tank (9a), a chemical cleaning pump (9b), and a cleaning security filter (9c) connected in sequence. The solution tank (9a) is filled with a cleaning solution. The ammonia nitrogen wastewater membrane absorption device (5) has a cleaning inlet and a cleaning outlet. The cleaning security filter (9c) is connected to the cleaning inlet, and the cleaning outlet is connected to the solution tank (9a).

5. The membrane absorption ammonia removal system for coal gasification wastewater according to claim 1, characterized in that: The ammonia nitrogen wastewater membrane absorption device (5) uses a PTFE hollow fiber membrane.

6. The coal gasification wastewater membrane absorption ammonia removal system according to claim 1, characterized in that: The pretreatment filtration system (1) includes a quartz sand filter (1a), a security filter (1b), and an ultrafilter (1c) connected in sequence.

7. The coal gasification wastewater membrane absorption ammonia removal system according to claim 1, characterized in that: The ammonia nitrogen wastewater is the effluent from ammonia-containing wastewater after stripping and ammonia removal, wherein the ammonia nitrogen content is 100 mg / L.

8. The coal gasification wastewater membrane absorption ammonia removal system according to claim 1, characterized in that: At least two ammonia nitrogen wastewater membrane absorption devices (5) are provided, and at least two ammonia nitrogen wastewater membrane absorption devices (5) are arranged in parallel.

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