A pyridine wastewater treatment system and method based on a hybrid membrane biofilm reactor

Abstract

This invention discloses a pyridine wastewater treatment system and method based on a hybrid membrane biofilm reactor, belonging to the field of wastewater treatment and environmental engineering technology. It includes a reactor body, a membrane oxygen supply unit, an inlet / outlet circulating return pipeline unit, a nutrient supply unit, and an operation control unit. The reactor body consists of a biofilm anoxic zone and a membrane aeration zone. The biofilm anoxic zone is filled with inert porous packing material as a biofilm carrier, while the membrane aeration zone is equipped with a silicone rubber hollow fiber membrane module to achieve bubble-free oxygen supply. Oxygen directly enters the biofilm interior via molecular diffusion, avoiding pyridine volatilization loss caused by bubble rupture. Membrane aeration significantly reduces gas-liquid interface disturbance, increases oxygen utilization to nearly 100%, effectively suppresses secondary pollution from volatile organic compounds such as pyridine, and reduces aeration energy consumption. Through the synergistic interaction between the biofilm anoxic zone and the membrane aeration zone, degradation and denitrification are coupled and enhanced, solving the problems of low efficiency, insufficient nitrogen removal, and secondary pollution in existing processes.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment and environmental engineering technology, and in particular to a pyridine wastewater treatment system and method based on a hybrid membrane biofilm reactor. Background Technology

[0002] Pyridine is a class of nitrogen-containing heterocyclic compounds widely used in the production of dyes, pesticides, and fine chemicals. Its wastewater typically contains about 1000 mg / L of pyridine and about 3000 ppm of ammonia nitrogen. If discharged directly without effective treatment, it will cause serious harm to the aquatic environment and human health.

[0003] Patent CN115417550A discloses a method for treating pyridine wastewater using resin adsorption. While this method effectively adsorbs pyridine and some ammonia nitrogen, the limited number of resin recyclables means that subsequent resin replacements increase costs. Existing treatment methods include anaerobic, anoxic, aerobic, and membrane biofilm reactor (MBfR) technologies. Anaerobic processes have low degradation rates, anoxic processes result in incomplete nitrogen removal, and while aerobic bubbling processes can efficiently remove pyridine, they are prone to secondary pollution due to pyridine volatilization, and nitrogen removal is not ideal. The single MBfR process has high oxygen utilization, but its ammonia nitrogen removal is insufficient due to limitations in membrane area and mass transfer efficiency.

[0004] Therefore, there is an urgent need to develop a new green and efficient process to achieve the synergistic removal of pyridine and nitrogen pollutants. Summary of the Invention

[0005] The purpose of this invention is to provide a pyridine wastewater treatment system and method based on a hybrid membrane biofilm reactor, which achieves efficient removal of pyridine and simultaneous removal of ammonia nitrogen, overcoming the problems of low efficiency, insufficient nitrogen removal and secondary pollution in existing processes, and solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A pyridine wastewater treatment system based on a hybrid membrane biofilm reactor includes a reactor body, a membrane oxygen supply unit, an inlet and outlet water circulation return pipeline unit, a nutrient supply unit, and an operation control unit. The reactor body consists of a lower biofilm anoxic zone and an upper membrane aeration zone. The lower biofilm anoxic zone is filled with inert porous packing material as a biofilm carrier, while the upper membrane aeration zone is equipped with a silicone rubber hollow fiber membrane module to achieve bubble-free oxygen supply. The use of a silicone rubber hollow fiber membrane for bubble-free oxygen supply allows oxygen to directly enter the biofilm via molecular diffusion, avoiding pyridine volatilization loss caused by bubble rupture. Simultaneously, membrane aeration significantly reduces gas-liquid interface disturbance, increases oxygen utilization to nearly 100%, effectively suppresses secondary pollution from volatile organic compounds such as pyridine, and reduces aeration energy consumption.

[0008] The anoxic zone of the biofilm is dominated by denitrifying bacteria, which use the NO3⁻ / NO2⁻ brought in by the reflux as electron acceptors to further reduce and decompose pyridine and its degradation intermediates. The membrane aeration zone is dominated by aerobic heterotrophic bacteria and nitrifying bacteria, which are responsible for the efficient aerobic degradation of pyridine and ammonia nitrification. The two zones form a synergistic coupling of "nitrification, denitrification and organic matter degradation" through internal circulation and reflux, which improves the overall reaction efficiency of the system.

[0009] The membrane oxygen supply unit is used to introduce air or pure oxygen at a pressure of 10-50 kPa. It slowly releases oxygen through the membrane wall of the membrane aeration zone, improving oxygen utilization and inhibiting secondary pollution caused by pyridine volatilization.

[0010] The inlet and outlet water circulation return pipeline unit is used to set up an internal circulation pump to enhance mass transfer in the membrane aeration zone and an external return pump to return the effluent from the membrane aeration zone to the biofilm anoxic zone. Pyridine wastewater enters from the bottom inlet of the reactor body and is discharged from the top outlet of the reactor body.

[0011] Among them, a circulating pump is used to increase the turbulence of the water in the membrane aeration zone to enhance mass transfer. At the same time, the effluent from the membrane aeration zone is returned to the biofilm anoxic zone according to a set return ratio to provide the nitrate / nitrite required for denitrification, thereby achieving the coupling of pyridine degradation and denitrification.

[0012] The nutrient supply unit is used to add nutrients and trace elements to the inlet pipe of the inlet tank or reactor body. Phosphorus source is added according to the mass ratio of pyridine theoretical oxygen demand (ThOD) to phosphorus (P) (ThOD:P = 200:1), and domestic sewage is added at 1-5% of the inlet flow rate to provide necessary minerals and trace elements.

[0013] The operation control unit is used to control the hydraulic residence time (12-36h), reaction temperature (20-35℃), pH (6.5-8.0), and key operating parameters including air supply pressure, circulation ratio, and reflux ratio.

[0014] Preferably, the reactor body is a hybrid membrane biofilm reactor (HMBfR), which is placed in a constant temperature incubator to maintain a water temperature of 25±1℃. The reactor body is made of plexiglass, with an inner diameter of 7cm and a height of 63cm.

[0015] Preferably, the height of the anoxic zone of the biofilm is 15-20cm, and the inert porous filler filling the anoxic zone of the biofilm is ceramsite with a particle size of 4-10mm.

[0016] Preferably, the silicone rubber hollow fiber membrane module installed in the membrane aeration zone consists of 124 silicone rubber membrane tubes, each with an inner diameter of 1.0 mm, an outer diameter of 1.5 mm, and a length of 50 cm, forming a membrane aeration zone with a height of 39 cm. The diameter of the hollow fiber membrane tubes in the membrane aeration zone is 1.0-1.5 mm, and the membrane area ranges from 0.292 to 1810 m².

[0017] Preferably, the effective surface area of ​​the membrane in the membrane aeration zone is 0.292 m², the specific surface area is 120.67 m² / m³, and the ceramsite filling the anoxic zone of the biofilm has a porosity of 5.63%, a porosity of 8.00%, an apparent density of 1545 kg / m³, and a bulk density of 1421 kg / m³.

[0018] Preferably, the membrane oxygen supply unit includes an oxygen cylinder and an air compressor, both of which are connected to the membrane aeration zone via pipelines. Pure oxygen or air supplied by the oxygen cylinder or air compressor is slowly released through the membrane wall of the membrane aeration zone.

[0019] Preferably, the pipeline is equipped with a ball valve and a pressure gauge, the pressure gauge being used to monitor the gas supply pressure in real time so that the gas supply pressure is within the range of 10-50 kPa.

[0020] According to another aspect of the present invention, a method for treating pyridine wastewater based on a hybrid membrane biofilm reactor is provided, implemented based on a pyridine wastewater treatment system based on a hybrid membrane biofilm reactor as described above, comprising the following steps:

[0021] Step 1, Influent Pretreatment and Dosing: Adjust the pH of the pyridine-containing wastewater to 6.5-8.0, and add phosphorus source at the influent tank or influent pipeline according to ThOD:P=200:1. If necessary, add 2% domestic sewage as trace elements, and then continuously pump it in through the bottom inlet of the reactor body.

[0022] Step 2, Anoxic Zone Reaction: Pyridine wastewater first enters the anoxic zone of the biofilm at the bottom of the reactor body, where it uses NO3− or NO2− brought in by the reflux as an electron acceptor for denitrification, while simultaneously partially degrading pyridine and its intermediate products.

[0023] Step 3, Membrane Aeration Zone Reaction: Pyridine wastewater rises into the membrane aeration zone at the top of the reactor body. Air or pure oxygen is introduced into the membrane for bubble-free oxygen supply, promoting the aerobic degradation of pyridine and the ammonia nitrogen nitrification reaction.

[0024] Step 4, Coupling of Circulation and Recirculation: Mass transfer in the membrane zone is enhanced through internal circulation, and the effluent from the membrane aeration zone is recirculated to the anoxic zone of the biofilm at a recirculation ratio to continuously provide the nitrate or nitrite required for denitrification, thereby achieving synergistic coupling of pyridine degradation and denitrification.

[0025] Step 5, Parameter Control: Control the hydraulic retention time within the range of 12-36 h, the temperature within the range of 20-35 ℃, and the air supply pressure within the range of 10-50 kPa, and adjust the circulation ratio and reflux ratio according to the water quality load;

[0026] Step 6, Effluent Treatment: The treated wastewater is discharged directly in compliance with standards, or enters CASS or other advanced biochemical treatment units to remove residual pyridine and nitrogen pollutants.

[0027] Preferably, the reflux ratio ranges from 0 to 4, and the circulation ratio ranges from 0 to 6, wherein the circulation ratio = internal circulation flow rate / inlet flow rate; and the reflux ratio = external reflux flow rate / inlet flow rate.

[0028] Preferably, the pyridine concentration in the pyridine-containing wastewater is 500-1000 mg / L, and the ammonia nitrogen concentration is 3000-5000 mg / L.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. The present invention has high pyridine and ammonia nitrogen removal efficiency and stable treatment effect. By forming a stable aerobic biofilm microenvironment in the membrane aeration zone, it promotes the gradual degradation of pyridine into small molecule organic matter and inorganic carbon through biological metabolic pathways such as hydroxylation and ring opening under aerobic conditions, while realizing the nitrification conversion of ammonia nitrogen to nitrite / nitrate. Combined with the denitrification effect in the anoxic zone of the lower biofilm, the overall pyridine removal rate of the system can reach more than 99%, and the ammonia nitrogen removal rate can reach more than 86%, which is significantly better than the traditional bubbling aerobic or single MBfR process.

[0031] 2. The bubble-free membrane aeration of the present invention enhances oxygen mass transfer and avoids secondary pollution from volatile pollutants. It uses a silicone rubber hollow fiber membrane for bubble-free oxygen supply, and oxygen enters the biofilm directly through molecular diffusion, avoiding the loss of pyridine volatilization caused by bubble rupture. At the same time, membrane aeration significantly reduces gas-liquid interface disturbance, improves oxygen utilization rate to nearly 100%, effectively suppresses secondary pollution problems of volatile organic compounds such as pyridine, and reduces aeration energy consumption.

[0032] 3. The present invention achieves enhanced coupling of degradation and denitrification by dividing the biofilm anoxic zone and the membrane aeration zone into separate zones. The biofilm anoxic zone and the membrane aeration zone construct a stable dissolved oxygen gradient: the biofilm anoxic zone is dominated by denitrifying bacteria, which use the NO3⁻ / NO2⁻ brought in by the reflux as electron acceptors to further reduce and decompose pyridine and its degradation intermediates; the membrane aeration zone is dominated by aerobic heterotrophic bacteria and nitrifying bacteria, which are responsible for the efficient aerobic degradation of pyridine and ammonia nitrification. The two zones form a synergistic coupling of "nitrification, denitrification and organic matter degradation" through internal circulation and reflux, thereby improving the overall reaction efficiency of the system.

[0033] 4. The aeration mode of this invention can be flexibly switched to adapt to different loads and water quality fluctuations. Its membrane oxygen supply unit can flexibly switch between air and pure oxygen aeration modes according to the changes in the concentration of pyridine and ammonia nitrogen in the influent. Under high load conditions, pure oxygen aeration is used to enhance nitrification and pyridine degradation kinetics, while air aeration is used under medium and low load conditions to reduce operating costs, thereby improving the system's adaptability to shock loads and water quality fluctuations.

[0034] 5. The microbial community of this invention is enriched in a partitioned manner, resulting in strong system stability and shock resistance. Through spatial partitioning and dissolved oxygen gradient control, aerobic pyridine-degrading bacteria, nitrifying bacteria, and denitrifying bacteria are directionally enriched in different functional zones, reducing functional competition and mutual inhibition among bacterial communities. The biofilm structure enhances the attachment stability and toxicity resistance of microorganisms, enabling the system to operate stably for a long time under high concentrations of pyridine and ammonia nitrogen, and its shock resistance performance is significantly better than that of traditional suspended sludge systems. Attached Figure Description

[0035] Figure 1 This is a structural diagram of the pyridine wastewater treatment system based on a hybrid membrane biofilm reactor according to the present invention;

[0036] Figure 2 This is a unit diagram of the pyridine wastewater treatment system based on a hybrid membrane biofilm reactor according to the present invention.

[0037] In the diagram: 1. Reactor body; 11. Biofilm anoxic zone; 12. Membrane aeration zone; 2. Internal circulation pump; 3. External return pump; 4. Oxygen cylinder; 5. Air compressor; 6. Piping; 61. Ball valve; 62. Pressure gauge. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To address the issues of low efficiency, insufficient nitrogen removal, and secondary pollution in existing processes, please refer to [link / reference needed]. Figures 1-2 This embodiment provides the following technical solution:

[0040] A pyridine wastewater treatment system based on a hybrid membrane biofilm reactor includes a reactor body 1, a membrane oxygen supply unit, an inlet / outlet circulating and reflux pipeline unit, a nutrient supply unit, and an operation control unit. The reactor body 1 includes a lower biofilm anoxic zone 11 and an upper membrane aeration zone 12. The lower biofilm anoxic zone 11 is filled with ceramic particles as a biofilm carrier, while the upper membrane aeration zone 12 is equipped with hollow fiber membrane tubes to supply air or pure oxygen, achieving bubble-free oxygen supply. Pyridine wastewater enters from the bottom of the reactor body 1 and passes sequentially through the biofilm anoxic zone 11 and the membrane aeration zone 12. Through circulation and reflux, aerobic degradation, ammonia nitrification, and denitrification reactions of pyridine are achieved. This system can operate flexibly in air / pure oxygen mode, achieving a pyridine removal rate of over 99% and an ammonia nitrogen removal rate of over 86%. It avoids secondary pollution, operates stably, and is suitable for the advanced treatment of high-concentration pyridine wastewater in the chemical industry.

[0041] Among them, the pyridine wastewater from the production workshop is acidified before entering reactor body 1, and the microorganisms and sludge are all from the water resource treatment plant.

[0042] The oxygenation performance of the membrane module used in the oxygenation experiment HMBfR was determined according to the Chinese standard "Determination of oxygen mass transfer in clean water for fine bubble diffusers" (CJ / T 475-2015, China). Sodium sulfite and cobalt chloride were used as deoxygenating agents to remove dissolved oxygen (DO) from distilled water.

[0043] Example 1

[0044] At the start-up of the hybrid membrane biofilm reactor (HMBfR), pyridine wastewater with a pH of around 10 was added. After being adjusted to neutral (around 7), the wastewater entered reactor body 1. Without any inflow material, the HMBfR operated under 10 kPa air-based membrane aeration at a water temperature of 25 ± 1 ℃. The effects of aeration pressure (10 kPa, 30 kPa, 50 kPa) and recirculation ratio (0, 1, 2) on the oxygen mass transfer performance of the membrane module were investigated. Three aeration experiments were conducted for each aeration condition. Then, the HMBfR was operated in continuous inflow mode under specific conditions with a hRT of 24 hours and a recirculation ratio of 1. The operating conditions of the HMBfR in continuous inflow mode are shown in Table 1.

[0045] Table 1: Operating conditions of HMBfR in continuous inflow mode

[0046] condition Reaction time (d) Pyridine influent concentration (ppm) HRT(h) Aeration pressure (kPa) Cycle ratio reflux ratio 1 1-20 980 24 10 1 0 2 21-40 970 24 30 1 0 3 41-60 980 24 30 0 0 4 61-80 960 24 30 0 0 5 81-100 1000 24 30 2 1 6 100-120 990 24 50 2 1

[0047] Example 2

[0048] After the successful start-up of the hybrid membrane biofilm reactor (HMBfR), the process performance under pure oxygen aeration substrate was investigated. The operating conditions of HMBfR for treating pyridine wastewater are shown in Table 2.

[0049] Table 2: Operating conditions for HMBfR treatment of pyridine wastewater

[0050] condition Reaction time (d) Pyridine influent concentration (ppm) HRT(h) Aeration pressure (kPa) Cycle ratio reflux ratio 1 1-20 980 24 10 2 2 2 21-40 970 24 30 2 2 3 41-60 980 24 30 2 2 4 61-80 960 24 30 4 4 5 81-100 1000 24 30 4 4 6 100-120 990 24 50 6 2

[0051] Example 3

[0052] A laboratory-scale hybrid membrane biofilm reactor (HMBfR) with a volume of 2.42 L, a lower ceramsite layer height of 18 cm, and an upper membrane area of ​​0.292 m² was used. The influent pyridine concentration was 1000 mg / L, and the HRT (heat recovery time) was 24 h. Air aeration was employed. The removal of pyridine in the air-HMBfR during the biofilm cultivation phase (conditions 1 and 2 in Table 1) is shown in Table 3. After 20 days of operation, the pyridine removal rate reached approximately 75.45%, indicating that pyridine-degrading bacteria had grown in reactor body 1. After biofilm cultivation, the aeration pressure was increased to 30 kPa. Subsequently, the pyridine concentration in the effluent of the air-HMBfR (hydrogen-based membrane biofilm reactor) gradually decreased to below 10 mg / L, with a pyridine removal rate exceeding 99%. The pyridine removal rate is shown in Table 3.

[0053] Table 3: Pyridine Removal Rate

[0054] reaction Aeration pressure / kPa Pyridine removal rate / % 1 10 75.45 2 10 75.43 3 10 75.49 4 30 99.12 5 30 99.23 6 30 99.37

[0055] Example 4

[0056] Based on Example 3, the gas supply method was pure oxygen, the membrane pressure was 30 kPa, and different hydraulic retention times (HRTs) were adjusted to 12h, 24h, and 36h. The effects of different hydraulic retention times are shown in Table 4.

[0057] Table 4: Effect of different hydraulic residence times

[0058] Reaction conditions HRT / h Pyridine removal rate / % Ammonia nitrogen removal rate / % 1 12 90.5 70.2 2 12 91.0 70.1 3 24 99.1 86.2 4 24 99.2 85.9 5 36 99.3 88.1 6 36 99.3 88.0

[0059] When the HRT is 12h, the pyridine removal rate is 90% and the ammonia nitrogen removal rate is 70%.

[0060] When the HRT is 24h, the pyridine removal rate is 99% and the ammonia nitrogen removal rate is 86%.

[0061] When the HRT is 36h, the pyridine removal rate is 99% and the ammonia nitrogen removal rate is 88%.

[0062] The results showed that extending the HRT was beneficial to improving the ammonia nitrogen removal rate, but under the 24h condition, both energy consumption and treatment effect were taken into account.

[0063] Example 5

[0064] In the same HMBfR device, air and pure oxygen were used for gas supply respectively, with an internal membrane pressure of 20 kPa and an HRT of 24 h. The comparison between air and pure oxygen supply methods is shown in Table 5.

[0065] Table 5: Comparison of Air and Pure Oxygen Supply Methods

[0066] Reaction conditions Gas supply method Pyridine removal rate / % Ammonia nitrogen removal rate / % Ammonia nitrogen concentration / ppm 1 Air 94.8 62.1 1140 2 Air 95.0 63.1 1110 3 Air 95.1 64.0 1080 4 oxygen 99.1 85.9 421 5 oxygen 99.2 86.1 419 6 oxygen 98.7 86.0 420

[0067] The results showed that when air was supplied, the pyridine removal rate was 95%, the ammonia nitrogen removal rate was 63%, and the effluent pyridine concentration was about 50 mg / L and the ammonia nitrogen concentration was about 1110 mg / L.

[0068] When pure oxygen is supplied, the pyridine removal rate is 99%, the ammonia nitrogen removal rate is 86%, the effluent pyridine concentration is ≤10 mg / L, and the ammonia nitrogen concentration is about 420 mg / L.

[0069] The comparison shows that pure oxygen supply significantly improves the denitrification effect of the system and is more suitable for treating high-concentration organic nitrogen wastewater.

[0070] Example 6

[0071] Based on Example 3, the hydraulic retention time was controlled at 24 h, the air supply method was pure oxygen, and the membrane pressure was 30 kPa. The reflux ratio was set to 1.0, 2.0 and 3.0 respectively, and the treatment effect of the system was tested to study the influence of different reflux ratios on the treatment effect.

[0072] When the reflux ratio is 1.0, the pyridine removal rate is 98%, the ammonia nitrogen removal rate is 78%, and the effluent ammonia nitrogen concentration is approximately 660 mg / L.

[0073] When the reflux ratio is 2.0, the pyridine removal rate is 99%, the ammonia nitrogen removal rate is 86%, and the ammonia nitrogen concentration in the effluent is approximately 420 mg / L.

[0074] When the reflux ratio is 3.0, the pyridine removal rate is 99%, the ammonia nitrogen removal rate is 88%, and the effluent ammonia nitrogen concentration is approximately 360 mg / L.

[0075] Experimental results show that appropriately increasing the reflux ratio can improve the efficiency of denitrification reaction, thereby increasing the ammonia nitrogen removal rate. The treatment effect is best when the reflux ratio is 2-3.

[0076] Example 7

[0077] The HMBfR effluent is further fed into the CASS process reactor for a cycle of 6 hours, during which the anoxic / aerobic operation alternates.

[0078] Operational results show that the pyridine concentration in the effluent from HMBfR is approximately 20 mg / L and the ammonia nitrogen concentration is 600 mg / L. After treatment with CASS, the pyridine concentration in the effluent is reduced to less than 5 mg / L and the ammonia nitrogen concentration is reduced to less than 100 mg / L.

[0079] The combined HMBfR and CASS process demonstrates that it can further improve the deep treatment effect and is suitable for industrial discharge scenarios with strict water quality requirements.

[0080] Example 8

[0081] To promote pyridine removal, acetic acid was added as a co-metabolite substrate. The pyridine removal rates after the addition of acetic acid are shown in Table 6.

[0082] Table 6: Pyridine removal rate after adding acetic acid

[0083] reaction Aeration pressure / kPa Pyridine removal rate / % 1 10 63.12 2 10 64.22 3 10 65.13

[0084] Compared with the results without acetic acid, the pyridine removal rate decreased. The addition of acetic acid was detrimental to the biodegradation of pyridine. This may be because the consumption of easily biodegradable acetic acid and the large amount of oxygen generated during the biodegradation process inhibited the biodegradation of pyridine. Under hypoxic conditions, the use of acetic acid had an adverse effect on the biodegradation of pyridine.

[0085] In summary, the pyridine wastewater treatment system and method based on a hybrid membrane biofilm reactor proposed in this invention can achieve a pyridine removal rate of >99% and an ammonia nitrogen removal rate of over 86%. It adopts bubble-free membrane aeration, with an oxygen utilization rate of nearly 100%, avoiding secondary pollution caused by pyridine volatilization. The lower biofilm anoxic zone 11 and the upper membrane aeration zone 12 operate in synergy, achieving efficient coupling of pyridine degradation, ammonia nitrogen nitrification and denitrification. The system can flexibly switch between air / pure oxygen aeration to adapt to different water quality loads. The microbial community is enriched in different zones, and the system has strong stability and shock resistance.

[0086] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A pyridine wastewater treatment system based on a hybrid membrane biofilm reactor, comprising a reactor body (1), a membrane oxygen supply unit, an inlet and outlet water circulation reflux pipeline unit, a nutrient supply unit and an operation control unit, characterized in that, The reactor body (1) is composed of a lower biological membrane anoxic zone (11) and an upper membrane aeration zone (12), wherein the lower biological membrane anoxic zone (11) is filled with inert porous filler as a biological membrane carrier, and the upper membrane aeration zone (12) is provided with a silicon rubber hollow fiber membrane assembly to realize bubble-free oxygen supply. The membrane oxygen supply unit is used for introducing air or pure oxygen, and the gas supply pressure is 10-50 kPa, and the oxygen is released slowly through the membrane wall of the membrane aeration zone (12). The water inlet and outlet circulation reflux pipeline unit is used to set an internal circulation pump (2) to enhance the mass transfer of the membrane aeration zone (12), and an external reflux pump (3) is set to return the water outlet of the membrane aeration zone (12) to the biological membrane anoxic zone (11). The nutrient supplement unit is used to supplement nutrients and trace elements at the water inlet pipeline of the water inlet tank or the reactor body (1), wherein the mass ratio of pyridine theoretical oxygen demand ThOD to phosphorus P is ThOD:P=200:1, and the necessary minerals and trace elements are provided by supplementing 1-5% of domestic sewage according to the water inlet flow. The operation control unit is used to control the hydraulic retention time of 12-36 h, the reaction temperature of 20-35℃, the pH of 6.5-8.0, and the key operation parameters including gas supply pressure, circulation ratio and reflux ratio.

2. The pyridine wastewater treatment system based on the hybrid membrane biofilm reactor according to claim 1, characterized in that, The reactor body (1) is a hybrid membrane biofilm reactor HMBfR, and the reactor body (1) is placed in a constant temperature incubator to keep the water temperature at 25±1℃, and the reactor body (1) is made of organic glass material with an inner diameter of 7 cm and a height of 63 cm.

3. The pyridine wastewater treatment system based on hybrid membrane biofilm reactor according to claim 2, characterized in that, The height of the biological membrane anoxic zone (11) is 15-20 cm, and the inert porous filler filled in the biological membrane anoxic zone (11) is ceramic particles with a particle size of 4-10 mm.

4. The pyridine wastewater treatment system based on hybrid membrane biofilm reactor according to claim 3, characterized in that, The silicon rubber hollow fiber membrane assembly arranged in the membrane aeration zone (12) is composed of 124 silicon rubber membrane tubes, each membrane tube has an inner diameter of 1.0 mm, an outer diameter of 1.5 mm, and a length of 50 cm, and forms a membrane aeration zone (12) with a height of 39 cm.

5. The pyridine wastewater treatment system based on hybrid membrane biofilm reactor according to claim 4, characterized in that, The effective surface area of the membrane in the membrane aeration zone (12) is 0.292 m2, the specific surface area is 120.67 m2 / m3, the porosity of the ceramic particles filled in the biological membrane anoxic zone (11) is 5.63%, the porosity is 8.00%, and the apparent density is 1545 kg / m3, and the bulk density is 1421 kg / m3.

6. The pyridine wastewater treatment system based on hybrid membrane biofilm reactor according to claim 5, characterized in that, The membrane oxygen supply unit includes an oxygen cylinder (4) and an air compressor (5), and the oxygen cylinder (4) and the air compressor (5) are connected to the membrane aeration zone (12) through a pipeline (6), wherein the pure oxygen or air introduced by the oxygen cylinder (4) or the air compressor (5) is released slowly through the membrane wall of the membrane aeration zone (12).

7. The pyridine wastewater treatment system based on hybrid membrane biofilm reactor according to claim 6, characterized in that, The pipeline (6) is provided with a ball valve (61) and a pressure gauge (62), and the pressure gauge (62) is used to monitor the gas supply pressure in real time, so that the gas supply pressure is in the range of 10-50 kPa.

8. A method for treating pyridine wastewater based on a hybrid membrane biofilm reactor, which is implemented based on the pyridine wastewater treatment system based on a hybrid membrane biofilm reactor according to claim 7, characterized in that, The method comprises the following steps: Step one, water pretreatment and dosing: adjust the pH of pyridine-containing wastewater to 6.5-8.0, and add phosphorus source at ThOD:P=200:1 in the water inlet tank or pipeline, then continuously pump into the reactor body (1) from the bottom inlet; Step two, anoxic zone reaction: pyridine wastewater first enters the biofilm anoxic zone (11) at the lower part of the reactor body (1), using NO3- or NO2- brought by backflow as electron acceptor for denitrification, while partially degrading pyridine and its intermediates; Step three, membrane aeration zone reaction: pyridine wastewater rises into the membrane aeration zone (12) at the upper part of the reactor body (1), air or pure oxygen is supplied into the membrane without bubbles to promote pyridine aerobic degradation and ammonia nitrogen nitrification; Step four, coupling of circulation and backflow: enhance mass transfer in the membrane zone by internal circulation, and backflow the effluent from the membrane aeration zone (12) to the biofilm anoxic zone (11) to continuously provide nitrate or nitrite required for denitrification, realizing the synergistic coupling of pyridine degradation and nitrogen removal; Step five, parameter control: control the hydraulic retention time in the range of 12-36 h, the temperature is 20-35 ℃, the gas supply pressure is 10-50 kPa, and adjust the circulation ratio and backflow ratio according to the water quality load; Step six, effluent treatment: the treated wastewater effluent directly meets the discharge standard, or enters the CASS or other biochemical advanced treatment unit to remove residual pyridine and nitrogen pollutants.

9. The method according to claim 8, wherein the method is characterized by, The backflow ratio ranges from 0 to 4, and the circulation ratio ranges from 0 to 6.

10. The method according to claim 9, wherein the method is characterized by, The pyridine concentration of the pyridine-containing wastewater is 500-1000 mg / L, and the ammonia nitrogen concentration is 3000-5000 mg / L.

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