Multi-mode adjustable membrane aeration deep denitrification sewage treatment system and method

Abstract

The invention discloses a multi-mode adjustable membrane aeration deep denitrification sewage treatment system and method. The device comprises a reaction container, wherein the reaction container is provided with a water inlet and a water outlet; a replaceable aeration membrane assembly and a filling carrier are arranged in the reaction container; an air inlet of the aeration membrane assembly is connected with an aeration device, and an air outlet of the aeration membrane assembly is communicated with the atmospheric environment; sewage is injected into the reaction container through the water inlet; the aeration device injects oxygen into the aeration membrane assembly according to a set aeration mode, and nitrifying bacteria attached to the outside of the aeration membrane assembly catalyze the oxygen and the sewage to carry out a nitration reaction to generate nitrate nitrogen; the filling carrier is used as an electron donor to reduce nitrate nitrogen into nitrogen; sewage is discharged through a water outlet after deep denitrification; the low-C / N wastewater composed of different nitrogen elements is efficiently treated, and the adaptability and denitrification efficiency of the device are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage treatment, and particularly relates to a multi-mode adjustable membrane aeration deep denitrification sewage treatment system and method. BACKGROUND

[0002] Deep denitrification has become an important demand for water environment governance, and low C / N nitrogen-containing wastewater (C / N < 3-5) becomes a difficult point of deep denitrification treatment due to insufficient carbon source and limited traditional biological denitrification. More importantly, the nitrogen composition of low C / N wastewater has significant diversity, and the demand of wastewater with different dominant nitrogen for microbial microenvironment (DO concentration, carbon source supply, and attached carrier) is greatly different.

[0003] Membrane aeration technology is one of the most commonly used core technologies for deep denitrification of low C / N nitrogen-containing wastewater due to its efficient oxygen mass transfer characteristics, but the traditional aeration membrane assembly has significant defects: the limited attached area leads to less microbial attachment, the aeration mode is fixedly designed and cannot adapt to the fluctuation of influent water quality, and a single aeration membrane assembly cannot simultaneously meet the microenvironment requirements of wastewater with different dominant nitrogen; in order to make up for the shortcomings of the traditional aeration membrane assembly, the existing technology attempts to combine the aeration membrane assembly with the filler to improve the microbial attachment capacity and mass transfer efficiency, but such combined technology still has key limitations: the filler material is single, the membrane-filler coupling structure is fixed, and the microenvironment parameters cannot be adjusted according to the nitrogen composition of the influent, so the existing combined device cannot accurately match the differentiated requirements of wastewater with different dominant nitrogen, resulting in unstable denitrification efficiency and poor adaptability. SUMMARY

[0004] The application provides a multi-mode adjustable membrane aeration deep denitrification sewage treatment system and method, which efficiently treats low C / N wastewater with different nitrogen compositions and improves the adaptability and denitrification efficiency of the device.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the application is as follows:

[0006] The application provides a multi-mode adjustable membrane aeration deep denitrification sewage treatment system in the first aspect, which comprises a reaction container; the reaction container is provided with an influent port and an effluent port;

[0007] The reaction container is provided with replaceable aeration membrane assemblies and filling carriers; the gas inlet of the aeration membrane assembly is connected to an aeration device, and the gas outlet of the aeration membrane assembly is in communication with the atmospheric environment;

[0008] Sewage is injected into the reaction container through the influent port; the aeration device injects oxygen into the aeration membrane assembly according to a set aeration mode, and the nitrifying bacteria attached outside the aeration membrane assembly catalyze the oxygen and the sewage to perform a nitrification reaction to produce nitrate nitrogen; the filling carrier acts as an electron donor to reduce the nitrate nitrogen into nitrogen; and the sewage is discharged through the effluent port after deep denitrification.

[0009] Further, the water inlet is arranged at the bottom of the reaction container, and the water outlet is arranged at the top of the reaction container; and an electromagnetic valve is arranged on the water inlet.

[0010] Further, the aeration membrane assembly is arranged vertically, and the internal gas flow direction thereof is from bottom to top; the gas inlet and the gas outlet are arranged at the top of the reaction container, the gas inlet is connected to the bottom of the aeration membrane assembly through a connecting pipe, and the gas outlet is connected to the top of the aeration membrane assembly through a connecting pipe.

[0011] Further, the aeration membrane assembly comprises a hollow fiber membrane substrate; and polyester fiber short or long fluff is arranged outside the hollow fiber membrane substrate; the length of the polyester fiber short fluff is less than L, and the length of the polyester fiber long fluff is greater than D.

[0012] Further, the hollow fiber membrane is made of PVDF, PES or the like, and the polyester fiber short or long fluff is made of wool, flax or the like, and the length of the fiber fluff can be adjusted according to the type of target wastewater; when low C / N wastewater dominated by nitrate nitrogen is adapted, 1-3 mm specification polyester fiber short fluff is selected; and when low C / N wastewater dominated by ammonia nitrogen is adapted, 5-10 mm specification polyester fiber long fluff is selected.

[0013] Further, the filling carrier is coconut shell filler.

[0014] Further, an agitator for stirring the sewage in the reaction container is arranged at the inner bottom of the reaction container, and the coconut shell filler is in a suspended flow state under the stirring action of the agitator.

[0015] Further, the filling carrier is ceramic composite filler, the internal micropores of the ceramic composite filler are filled with carbon source, and the surface of the ceramic composite filler is coated with a hydroxypropyl methyl cellulose film. The carbon source in the present application includes but is not limited to starch and cellulose.

[0016] Further, the ceramic composite fillers and the aeration membrane assemblies are arranged around the center of the reaction container, and the ceramic composite fillers and the aeration membrane assemblies are distributed alternately.

[0017] Further, the aeration device comprises a variable frequency aeration pump, a pressure regulating valve and a gas distributor; the variable frequency aeration pump, the pressure regulating valve and the gas distributor are sequentially connected through a gas conveying pipeline; and the gas distributor is in communication with the aeration membrane assemblies.

[0018] Further, the reaction container is provided with a pH sensor, an ammonia nitrogen / nitrate nitrogen online sensor, a dissolved oxygen sensor, a temperature sensor and a differential pressure transmitter; the pH sensor, the ammonia nitrogen / nitrate nitrogen online sensor, the dissolved oxygen sensor, the temperature sensor and the differential pressure transmitter are electrically connected to the input end of the intelligent electric control box; and the intelligent electric control box is electrically connected to the variable frequency aeration pump, the pressure regulating valve and the electromagnetic valve.

[0019] The application further provides an application method of the multi-mode adjustable membrane aeration deep denitrification sewage treatment system.

[0020] The type coupling mode of the aeration membrane assembly and the filling carrier is selected according to the composition of nitrogen in the sewage; the type of the aeration membrane assembly includes a short-fleece aeration membrane assembly and a long-fleece aeration membrane assembly, and the type of the filling carrier includes coconut shell filler and ceramsite composite filler;

[0021] The sewage is injected into the reaction container through the water inlet; the aeration device injects oxygen into the aeration membrane assembly according to the set aeration mode, and the nitrifying bacteria attached to the outside of the aeration membrane assembly catalyze the oxygen and the sewage to perform a nitrification reaction to generate nitrate nitrogen; the filling carrier serves as an electron donor to reduce the nitrate nitrogen into nitrogen; and the sewage is discharged through the water outlet after deep denitrification.

[0022] Further, the water inlet is provided with an electromagnetic valve, and the reaction container is provided with a pH sensor, an ammonia nitrogen / nitrate nitrogen online sensor, a dissolved oxygen sensor, a temperature sensor and a differential pressure transmitter; the pH sensor, the ammonia nitrogen / nitrate nitrogen online sensor, the dissolved oxygen sensor, the temperature sensor and the differential pressure transmitter are electrically connected to the input end of the intelligent electric control box; and the intelligent electric control box is electrically connected to the aeration device and the electromagnetic valve.

[0023] The intelligent electric control box controls the electromagnetic valve to adjust the water inflow of the reaction container and controls the aeration mode and the aeration pressure of the aeration device according to the detection information of the dissolved oxygen sensor, the temperature sensor and the differential pressure transmitter; the aeration mode of the aeration device includes high-intensity intermittent aeration and low-intensity continuous aeration.

[0024] The intelligent electric control box determines whether the deep denitrification of the sewage is up to the standard according to the detection information of the pH sensor and the ammonia nitrogen / nitrate nitrogen online sensor, and the sewage is discharged from the reaction container when the deep denitrification of the sewage is up to the standard.

[0025] Further, the type coupling mode of the aeration membrane assembly and the filling carrier is that the long-fleece aeration membrane assembly is combined with the ceramsite composite filler, a plurality of ceramsite composite fillers and a plurality of aeration membrane assemblies are arranged around the center of the reaction container, and the ceramsite composite fillers and the aeration membrane assemblies are distributed alternately; and the aeration mode of the aeration device is high-intensity intermittent aeration.

[0026] Further, the aeration membrane assembly and the type of filling carrier are coupled in a short-fleece aeration membrane assembly and coconut shell filler combination, and the coconut shell filler is in a suspended flow state in the sewage; and the aeration mode of the aeration device is selected as low-intensity continuous aeration.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] In the present application, the aeration membrane assembly and the filling carrier can be replaced, and the type and specification of the core treatment component can be flexibly adjusted according to the nitrogen composition, pollution load and other water quality characteristics of different sewage, breaking the limitation of the traditional sewage treatment equipment that “a single configuration is adapted to a single water quality”. Whether it is high-ammonia-nitrogen wastewater or high-nitrate-nitrogen wastewater, the aeration membrane assembly and the filling carrier can be replaced to build a targeted treatment system, significantly improving the adaptability of the system to complex and variable sewage water quality and expanding the application range.

[0029] In the present application, the aeration device precisely injects oxygen according to the set aeration mode, and the oxygen supply intensity and rhythm can be adjusted according to the oxygen demand of the nitrification reaction, providing a stable and suitable living environment for the nitrifying bacteria outside the aeration membrane assembly, promoting the efficient nitrification reaction, and ensuring that ammonia nitrogen is fully converted into nitrate nitrogen. At the same time, the filling carrier directly acts as an electron donor to promote the reduction of nitrate nitrogen to nitrogen, eliminating the need for additional addition of electron donors, allowing the nitrification and denitrification reactions to efficiently connect, forming a complete denitrification chain, and strengthening the deep denitrification effect.

[0030] In the present application, the filling carrier has dual functions of biological adhesion and electron donor, eliminating the need for additional addition of chemical reagents or carbon sources, reducing material consumption and operation cost, and avoiding secondary pollution of water bodies by chemicals. In addition, the core components of the system can be directly replaced without the need for complex modification of the main equipment, the operation process is simple, the technical threshold and labor cost of equipment maintenance are reduced, the downtime for maintenance is reduced, and the continuous and stable treatment process is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a structural diagram of a multi-mode adjustable membrane aeration deep denitrification sewage treatment system provided by embodiment 1 of the present application;

[0032] Figures 2-3 is a structural diagram of a reaction container provided by embodiment 2 of the present application;

[0033] Figures 4-5 is a top view of the reaction container provided by embodiment 2 of the present application;

[0034] Figures 4-5 is a structural diagram of a reaction container provided by embodiment 3 of the present application;

[0035] Figures 4-5 is a top view of the reaction container provided by embodiment 3 of the present application;

[0036] In the diagram, 1 is the reaction vessel, 2 is the agitator, 3 is the aeration membrane assembly, 4 is the packing carrier, 5 is the inlet, 6 is the outlet, 7 is the aeration device, and 8 is the intelligent electrical control box. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0038] Example 1

[0039] like Figure 1 As shown, this embodiment provides a multi-mode adjustable membrane aeration deep denitrification wastewater treatment system, including a reaction vessel 1, the inner wall of which is provided with an anti-bioadhesion coating; the inlet 5 is located at the bottom of the reaction vessel 1, and the outlet 6 is located at the top of the reaction vessel 1; a solenoid valve 9 is provided on the inlet 5.

[0040] The reaction vessel 1 is equipped with a replaceable aeration membrane assembly 3 and a filling carrier 4;

[0041] The filling carrier 4 is coconut shell filler; the bottom of the reaction vessel 1 is equipped with a stirrer 2 for stirring the sewage in the reaction vessel, and the coconut shell filler is in a suspended flow state under the stirring action of the stirrer 2.

[0042] Alternatively, the filling carrier 4 may be a ceramsite composite filler, with its internal micropores filled with a carbon source and its surface coated with a hydroxypropyl methylcellulose film. In this invention, the carbon source includes, but is not limited to, starch and cellulose. Several ceramsite composite fillers and several aeration membrane components are arranged around the center of the reaction vessel, and the ceramsite composite fillers and aeration membrane components are distributed alternately.

[0043] The aeration membrane component 3 includes a hollow fiber membrane substrate; the hollow fiber membrane substrate is provided with short polyester fiber fibers or long polyester fiber fibers; the length of the short polyester fiber fibers is less than L, where L=3mm, and the length of the long polyester fiber fibers is greater than D, where D=5mm.

[0044] For wastewater primarily composed of nitrate nitrogen (such as secondary effluent from municipal sewage), short-fiber aeration membrane modules, lightweight coconut shell packing, and a fluid-flow-oriented coupling structure can be selected, combined with low-intensity continuous aeration, to create a high-mass-transfer-efficiency anoxic environment. For wastewater primarily composed of ammonia nitrogen (such as freshwater aquaculture effluent), long-fiber aeration membrane modules, modified ceramsite composite packing, and an alternating series coupling structure can be used, combined with high-intensity intermittent aeration, to form an alternating aerobic-anoxic microenvironment gradient. This flexible and adjustable configuration mode allows the device to adapt to low C / N wastewater with different pollution characteristics without overall modification. It can be adapted simply by adjusting the specifications of the core components and switching the aeration mode, greatly expanding the application scenarios and solving the pain points of poor adaptability and difficulty in coping with water quality fluctuations in traditional devices.

[0045] The aeration membrane assembly 3 is vertically arranged, and the gas flow direction inside it is from bottom to top; the air inlet and the air outlet of the aeration membrane assembly 3 are located at the top of the reaction vessel 1, the air inlet is connected to the bottom of the aeration membrane assembly 3 through a connecting pipe, and the air outlet is connected to the top of the aeration membrane assembly 3 through a connecting pipe; the air inlet of the aeration membrane assembly is connected to the aeration device 7, and the air outlet of the aeration membrane assembly 3 is connected to the atmospheric environment;

[0046] The aeration device 7 includes a variable frequency aeration pump, a pressure regulating valve, and a gas distributor; the variable frequency aeration pump, the pressure regulating valve, and the gas distributor are connected in sequence through an air supply pipeline; the gas distributor is connected to several aeration membrane components.

[0047] The reaction vessel 1 is equipped with a pH sensor, an online ammonia nitrogen / nitrate nitrogen sensor, a dissolved oxygen sensor, a temperature sensor, and a differential pressure transmitter; the pH sensor, the online ammonia nitrogen / nitrate nitrogen sensor, the dissolved oxygen sensor, the temperature sensor, and the differential pressure transmitter are electrically connected to the input terminal of the intelligent electrical control box 8; the intelligent electrical control box 8 is electrically connected to the stirrer 2, the frequency converter aeration pump, the pressure regulating valve, and the solenoid valve 9.

[0048] The intelligent electrical control box 8 is electrically connected in real time to the aeration device 7 and the agitator 2, and can automatically trigger mode switching based on water quality data collected by sensors, adapting to different treatment scenarios without manual intervention. Its parameter control precision can accurately match the metabolic needs of denitrifying bacteria, effectively avoiding effluent exceeding standards due to water quality fluctuations. Compared to traditional membrane aeration devices that rely on manual monitoring and parameter adjustment, this intelligent control mode not only reduces the technical threshold and labor intensity of manual operation but also avoids operational deviations caused by human error.

[0049] Wastewater is injected into the reaction vessel 1 through inlet 5; the aeration device 7 injects oxygen into the aeration membrane component according to the set aeration mode; the nitrifying bacteria attached to the outside of the aeration membrane component 3 catalyze the oxygen and wastewater to nitrify and produce nitrate nitrogen; the filling carrier 4 acts as an electron donor to reduce nitrate nitrogen to nitrogen gas; the wastewater is discharged through outlet 6 after deep denitrification.

[0050] The anti-biofilm coating on the sidewall of reaction vessel 1, the scouring effect of the adjustable-speed stirrer, and the dynamic movement of the packing carrier 4 in the flow field effectively reduce excessive biofilm adhesion and membrane clogging, delaying component performance degradation. At the control level, the intelligent electrical control box 8 integrates multiple sensors such as pH, ammonia nitrogen / nitrate nitrogen, and dissolved oxygen, as well as a differential pressure transmitter. This allows for real-time monitoring of key parameters during the reaction process, timely adjustment of operating indicators such as stirring speed and aeration pressure, and prevention of decreased treatment efficiency due to parameter imbalances. This combination of "structural anti-clogging + intelligent control" significantly extends the continuous operation cycle of the device and reduces the cleaning frequency. It not only reduces downtime maintenance time and reagent consumption but also lowers the risk of failure caused by component clogging and performance fluctuations, ensuring the continuity and stability of the treatment process.

[0051] Example 2

[0052] like Figures 2-3 As shown, this embodiment provides an application method for a multi-mode adjustable membrane aeration deep denitrification wastewater treatment system. The application method is applicable to the membrane aeration deep denitrification wastewater treatment system described in Embodiment 1, and includes:

[0053] Based on the nitrogen composition of the wastewater, a combination of short-fiber aeration membrane module and coconut shell packing (filling rate 10%) is selected. The coconut shell packing is in a suspended flow state in the wastewater. The short-fiber aeration membrane module includes a hollow fiber membrane substrate. The hollow fiber membrane substrate is provided with polyester fiber short fibers.

[0054] The polyester fiber-modified short fibers on the exterior of the short-fiber aeration membrane module form a thin biofilm with low mass transfer resistance, rapid nitrate nitrogen mass transfer, high carbon source utilization efficiency, and more precise DO control. Lightweight coconut shell packing can continuously and slowly release carbon sources, enhancing denitrification. Furthermore, the 10% filling ratio of the coconut shell packing allows it to remain in a suspended flow state under adjustable-speed agitator operation, ensuring full contact with the aeration membrane module; the fluid-encircling coupling ensures thorough contact between wastewater and the packing material, accelerating the mass transfer process between the short-fiber biofilm on the aeration membrane surface and the biofilm on the packing material surface.

[0055] Meanwhile, the fluidized bed packing gently scours the membrane surface during the swirling process, promoting biofilm renewal and reducing the risk of membrane fouling. The short fibers and coconut shell packing work synergistically to increase the amount of denitrifying bacteria, while the fluidized bed coupling optimizes mass transfer. Low-intensity aeration maintains an anoxic environment, achieving deep nitrogen removal from low C / N wastewater, which is primarily composed of nitrate nitrogen.

[0056] The inlet 5 is equipped with a solenoid valve 9. The reaction vessel is equipped with a pH sensor, an online ammonia nitrogen / nitrate nitrogen sensor, a dissolved oxygen sensor, a temperature sensor, and a differential pressure transmitter. The pH sensor, the online ammonia nitrogen / nitrate nitrogen sensor, the dissolved oxygen sensor, the temperature sensor, and the differential pressure transmitter are electrically connected to the input terminal of the intelligent electrical control box 8. The intelligent electrical control box 8 is electrically connected to the stirrer 2, the aeration device 7, and the solenoid valve 9.

[0057] The intelligent electrical control box 8 controls the solenoid valve to adjust the water inlet flow of the reaction vessel and the aeration mode and aeration pressure of the aeration device 7 based on the detection information of the dissolved oxygen sensor, temperature sensor and differential pressure transmitter; the aeration mode of the aeration device 7 is low-intensity continuous aeration.

[0058] Wastewater is injected into the reaction vessel 1 through the inlet; the aeration device 7 injects oxygen into the aeration membrane component according to the set aeration mode; the nitrifying bacteria attached to the outside of the aeration membrane component 3 catalyze the oxygen and wastewater to undergo a nitrification reaction to produce nitrate nitrogen; the coconut shell packing acts as an electron donor to reduce nitrate nitrogen to nitrogen gas.

[0059] The intelligent electrical control box 8 determines whether the deep denitrification of wastewater meets the standard based on the detection information of the pH sensor and the online ammonia nitrogen / nitrate nitrogen sensor. When the deep denitrification of wastewater meets the standard, it is discharged from the reaction vessel.

[0060] Comparison device 1: Traditional PVDF aeration membrane module + PP suspended filler (10% filling rate) + fluidized surrounding coupling + low-intensity aeration;

[0061] Table 1. Comparison of the operating effects of this embodiment and comparison device 1.

[0062]

[0063] As shown in Table 1, this embodiment demonstrates significant advantages over the conventional PVDF aeration membrane module paired with PP suspended packing in treating low C / N wastewater dominated by nitrate nitrogen. Specifically, the nitrate nitrogen removal rate is significantly improved compared to the comparative device, and the total nitrogen removal effect is also doubled. The COD and ammonia nitrogen removal rates are also significantly better than the comparative device. This effect is attributed to the characteristics of the short-fiber membrane reducing mass transfer resistance and improving nitrate nitrogen mass transfer efficiency, as well as the continuous slow release of carbon source and enhanced denitrification effect of the lightweight coconut shell packing. This achieves precise targeted treatment of low C / N wastewater dominated by nitrate nitrogen, significantly improving denitrification efficiency and carbon source utilization efficiency.

[0064] Example 3

[0065] like Figures 4-5As shown, this embodiment provides an application method for a multi-mode adjustable membrane aeration deep denitrification wastewater treatment system. The application method is applicable to the membrane aeration deep denitrification wastewater treatment system described in Embodiment 1, and includes:

[0066] Based on the nitrogen composition in the wastewater, a combination of long-fiber aeration membrane components and ceramsite composite fillers is selected. The long-fiber aeration membrane component includes a hollow fiber membrane substrate; the hollow fiber membrane substrate is covered with polyester fiber long fibers; several ceramsite composite fillers and several aeration membrane components are arranged around the center of the reaction vessel, and the ceramsite composite fillers and aeration membrane components are distributed alternately.

[0067] Polyester fibers with long fibers form a thick biofilm with a large amount of microorganisms attached, which is suitable for constructing a microenvironment gradient of "aerobic surface and anoxic interior" and enriching denitrifying bacteria, thereby achieving simultaneous nitrification and denitrification on the carrier without the need for staged treatment.

[0068] The modified ceramsite composite filler has micropores inside the ceramsite matrix filled with carbon sources such as starch and cellulose, and the surface is coated with a hydroxypropyl methylcellulose film to form a slow-release layer.

[0069] Alternating series coupling: The "membrane-filler-sewage" system forms an "alternating aerobic-anoxic flow field". The long-fiber aeration membrane module and the modified ceramsite composite filler are arranged alternately in series at a ratio of "1 membrane 1 filler". During aeration, the aerobic zone (DO 2-3mg / L) formed around the aeration membrane module is physically separated from the anoxic zone (DO < 0.5mg / L) inside the filler. When the sewage flows through, it will pass through the aerobic zone (nitrification of ammonia nitrogen) - the anoxic zone (denitrification of nitrate nitrogen) - the aerobic zone - the anoxic zone in sequence, realizing the continuous conversion of "ammonia nitrogen - nitrate nitrogen - nitrogen gas".

[0070] Through the synergistic effect of "long fibers providing DO gradient and denitrifying bacteria attachment - modified ceramic particles adsorbing carbon sources and enhancing anoxic conditions - alternating series separation of micro-zones and optimization of flow field - high-intensity intermittent aeration regulating DO and carbon source utilization", high-efficiency nitrogen removal from low C / N wastewater with ammonia nitrogen as the main component is finally achieved.

[0071] The inlet 5 is equipped with a solenoid valve 9. The reaction vessel is equipped with a pH sensor, an online ammonia nitrogen / nitrate nitrogen sensor, a dissolved oxygen sensor, a temperature sensor, and a differential pressure transmitter. The pH sensor, the online ammonia nitrogen / nitrate nitrogen sensor, the dissolved oxygen sensor, the temperature sensor, and the differential pressure transmitter are electrically connected to the input terminal of the intelligent electrical control box 8. The intelligent electrical control box 8 is electrically connected to the aeration device 7 and the solenoid valve 9.

[0072] The intelligent electrical control box 8 controls the solenoid valve 9 to adjust the water inlet flow of the reaction vessel and control the aeration mode and aeration pressure of the aeration device 7 based on the detection information of the dissolved oxygen sensor, temperature sensor and differential pressure transmitter; the aeration mode of the aeration device 7 is high-intensity intermittent aeration.

[0073] Wastewater is injected into the reaction vessel 1 through inlet 5; the aeration device 7 injects oxygen into the aeration membrane component according to the set aeration mode; the nitrifying bacteria attached to the outside of the aeration membrane component 3 catalyze the oxygen and wastewater to undergo a nitrification reaction to produce nitrate nitrogen; the ceramsite composite filler acts as an electron donor to reduce nitrate nitrogen to nitrogen gas.

[0074] The intelligent electrical control box 8 determines whether the deep denitrification of wastewater meets the standard based on the detection information of the pH sensor and the online ammonia nitrogen / nitrate nitrogen sensor. When the deep denitrification of wastewater meets the standard, it is discharged from the reaction vessel.

[0075] Comparative device 2: pure PVDF hollow fiber membrane + PP suspended filler (fill rate 20%) + alternating series coupling + high-intensity intermittent aeration;

[0076] Table 2. Comparison of the operating effects of this embodiment and comparison device 2.

[0077]

[0078] As shown in Table 2, in this embodiment, the long fibers of polyester fibers can construct a microenvironmental gradient of "aerobic surface and anoxic interior," significantly increasing the attachment of denitrifying bacteria. The modified ceramsite composite packing can slowly release carbon sources and enhance the anoxic environment. Alternating series coupling forms an "alternating aerobic-anoxic flow field," which, combined with high-intensity intermittent aeration, precisely controls dissolved oxygen. Multiple components work together to achieve continuous conversion of ammonia nitrogen to nitrogen. This mode effectively compensates for the deficiencies of insufficient microbial attachment, unbalanced carbon source supply, and low mass transfer efficiency in the comparative device 2. It not only makes the removal effect of ammonia nitrogen, nitrate nitrogen, and total nitrogen far exceed that of the comparative device, but also efficiently degrades CODMn, achieving targeted deep treatment of low C / N wastewater with ammonia nitrogen as the main component, and significantly improving the denitrification efficiency and the comprehensiveness and stability of pollution removal.

[0079] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multi-mode adjustable membrane aeration deep denitrification wastewater treatment system, characterized in that, Includes a reaction vessel; the reaction vessel is provided with an inlet and an outlet; The reaction vessel is equipped with a replaceable aeration membrane assembly and a filling carrier; the air inlet of the aeration membrane assembly is connected to an aeration device, and the exhaust port of the aeration membrane assembly is connected to the atmospheric environment. Wastewater is injected into the reaction vessel through the inlet; the aeration device injects oxygen into the aeration membrane component according to the set aeration mode; the nitrifying bacteria attached to the outside of the aeration membrane component catalyze the oxygen and wastewater to undergo a nitrification reaction to produce nitrate nitrogen; the filling carrier acts as an electron donor to reduce the nitrate nitrogen to nitrogen gas; the wastewater is discharged through the outlet after deep denitrification.

2. The membrane aeration deep denitrification wastewater treatment system according to claim 1, characterized in that, The water inlet is located at the bottom of the reaction vessel, and the water outlet is located at the top of the reaction vessel; a solenoid valve is provided on the water inlet.

3. The membrane aeration deep denitrification wastewater treatment system according to claim 1, characterized in that, The aeration membrane assembly is vertically arranged, and the gas flow direction inside it is from bottom to top; the air inlet and the exhaust outlet are located at the top of the reaction vessel, the air inlet is connected to the bottom of the aeration membrane assembly through a connecting pipe, and the exhaust outlet is connected to the top of the aeration membrane assembly through a connecting pipe.

4. The membrane aeration deep denitrification wastewater treatment system according to claim 1 or 3, characterized in that, The aeration membrane assembly includes a hollow fiber membrane substrate; the hollow fiber membrane substrate is provided with short polyester fiber fibers or long polyester fiber fibers; the length of the short polyester fiber fibers is less than L, and the length of the long polyester fiber fibers is greater than D.

5. The membrane aeration deep denitrification wastewater treatment system according to claim 1, characterized in that, The filling carrier is coconut shell packing; the bottom of the reaction vessel is equipped with a stirrer for stirring the wastewater in the reaction vessel, and the coconut shell packing is in a suspended flow state under the stirring action of the stirrer.

6. The membrane aeration deep denitrification wastewater treatment system according to claim 1, characterized in that, The filling carrier is a ceramic aggregate composite filler, the internal micropores of which are filled with carbon source, and the surface of the ceramic aggregate composite filler is coated with a hydroxypropyl methylcellulose film; several ceramic aggregate composite fillers and several aeration membrane components are arranged around the center of the reaction vessel, and the ceramic aggregate composite fillers and aeration membrane components are staggered.

7. The membrane aeration deep denitrification wastewater treatment system according to claim 2, characterized in that, The aeration device includes a variable frequency aeration pump, a pressure regulating valve, and a gas distributor; the variable frequency aeration pump, the pressure regulating valve, and the gas distributor are connected in sequence through a gas supply pipeline; the gas distributor is connected to several aeration membrane modules.

8. The membrane aeration deep denitrification wastewater treatment system according to claim 7, characterized in that, The reaction vessel is equipped with a pH sensor, an online ammonia nitrogen / nitrate nitrogen sensor, a dissolved oxygen sensor, a temperature sensor, and a differential pressure transmitter; the pH sensor, the online ammonia nitrogen / nitrate nitrogen sensor, the dissolved oxygen sensor, the temperature sensor, and the differential pressure transmitter are electrically connected to the input terminal of the intelligent electrical control box; the intelligent electrical control box is electrically connected to the frequency converter aeration pump, the pressure regulating valve, and the solenoid valve.

9. The application method of the membrane aeration deep denitrification wastewater treatment system according to any one of claims 1 to 8, characterized in that, include: The coupling method of aeration membrane components and filling carriers is selected according to the nitrogen composition of the wastewater; the types of aeration membrane components include short-fiber aeration membrane components and long-fiber aeration membrane components, and the types of filling carriers include coconut shell filler and ceramsite composite filler. Wastewater is injected into the reaction vessel through the inlet; the aeration device injects oxygen into the aeration membrane component according to the set aeration mode; the nitrifying bacteria attached to the outside of the aeration membrane component catalyze the oxygen and wastewater to undergo a nitrification reaction to produce nitrate nitrogen; the filling carrier acts as an electron donor to reduce the nitrate nitrogen to nitrogen gas; the wastewater undergoes deep denitrification and meets the standards before being discharged through the outlet.

10. The application method of the membrane aeration deep denitrification wastewater treatment system according to claim 9, characterized in that, The coupling method between the aeration membrane module and the filling carrier is a combination of long-fiber aeration membrane module and ceramsite composite filler. Several ceramsite composite fillers and several aeration membrane modules are arranged around the center of the reaction vessel, and the ceramsite composite fillers and aeration membrane modules are staggered. The aeration method of the aeration device is high-intensity intermittent aeration.

11. The application method of the membrane aeration deep denitrification wastewater treatment system according to claim 9, characterized in that, The coupling method between the aeration membrane module and the filling carrier is a combination of short-fiber aeration membrane module and coconut shell filler, with the coconut shell filler in a suspended flow state in the sewage; the aeration method of the aeration device is low-intensity continuous aeration.

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