A system for treating recalcitrant organic matter in wastewater

Abstract

This invention discloses a system for treating recalcitrant organic matter in wastewater, belonging to the field of wastewater treatment technology. Wastewater undergoes continuous reaction in anaerobic, anoxic, and aerobic reactors to achieve nitrogen and phosphorus removal. In the anoxic and aerobic reactors, nitrite and nitrate gradually accumulate. Irradiation with 365nm and 254nm wavelength ultraviolet light causes nitrite and nitrate to generate highly oxidizing hydroxyl radicals. Under the action of these hydroxyl radicals, the recalcitrant organic matter in the wastewater is decomposed. In the aerobic reactor, nitrification is completed, with a portion recirculated into the anoxic reactor and the remainder flowing into the 254nm wavelength ultraviolet irradiator. Under ultraviolet irradiation, nitrate ions generate hydroxyl radicals, decomposing the recalcitrant organic matter. This invention is based on A... 2 Built on the basis of the O process, it saves costs, degrades some recalcitrant organic matter, enhances denitrification, and improves water quality.

Description

[0001] This application is a divisional application of a patent application entitled "A Treatment System for Recalcitrant Organic Matter in Wastewater", the original application was filed on January 6, 2022, and the application number is 202210009567.X. Technical Field

[0002] This invention relates to a system for treating recalcitrant organic matter in wastewater, belonging to the field of wastewater treatment technology. Background Technology

[0003] Recalcitrant organic compounds (ROCs) pose serious health risks to humans and can contribute to malignant cell transformation. Therefore, improving water treatment technologies and accelerating innovative applications are crucial for controlling water pollution.

[0004] Traditional A 2 The O process, also known as the anaerobic-anoxic-aerobic process, can be used for secondary or tertiary wastewater treatment. Because it simultaneously removes nitrogen and phosphorus, the system is simple to operate, has low operating costs, produces little residual sludge, and achieves BOD5 and COD removal rates of up to 90%, total nitrogen removal rates of over 70%, and phosphorus removal rates of around 90%, demonstrating excellent removal efficiency. It is currently a commonly used wastewater treatment process in wastewater treatment plants. However, the traditional A... 2 The O process has difficulty in further improving its nitrogen and phosphorus removal efficiency, and some recalcitrant organic matter cannot be removed, which affects the reaction rate and ultimately prevents the treated wastewater from meeting discharge standards. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a treatment system for recalcitrant organic matter in wastewater. This system improves the denitrification effect of wastewater and effectively degrades recalcitrant organic matter in wastewater, enabling the treated wastewater to meet discharge standards.

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

[0007] This invention provides a system for treating recalcitrant organic matter in wastewater, comprising a 365nm wavelength ultraviolet irradiator and a 254nm wavelength ultraviolet irradiator. The 365nm wavelength ultraviolet irradiator is equipped with a 365nm wavelength ultraviolet lamp. An anoxic reactor is located on one side of the 365nm wavelength ultraviolet irradiator, and an aerobic reactor is located on the other side. The anoxic reactor is connected to the 365nm wavelength ultraviolet irradiator inlet via its outlet. The other side of the anoxic reactor is connected to an anaerobic reactor. The anaerobic reactor is located on the side furthest from the anoxic reactor. The aerobic reactor is equipped with an anaerobic reactor inlet. The aerobic reactor is connected to the outlet of a 365nm wavelength ultraviolet irradiator via the aerobic reactor inlet. On the other side of the aerobic reactor, the aerobic reactor outlet is connected to a 254nm wavelength ultraviolet irradiator inlet via the aerobic reactor outlet. The other side of the 254nm wavelength ultraviolet irradiator is connected to its outlet. The 254nm wavelength ultraviolet irradiator is equipped with a 254nm wavelength ultraviolet lamp. An aeration device and a mixed liquor reflux pump are provided at the bottom of the aerobic reactor.

[0008] This invention provides a method for treating recalcitrant organic matter in wastewater. Using the aforementioned system, wastewater is introduced into the anaerobic reactor through the inlet. The wastewater undergoes continuous reaction in the anaerobic, anoxic, and aerobic reactors to remove nitrogen and phosphorus. In the anoxic and aerobic reactors, nitrite and nitrate gradually accumulate. After being irradiated with 365nm and 254nm ultraviolet light, the nitrite and nitrate generate highly oxidizing hydroxyl radicals. Under the action of these hydroxyl radicals, some of the recalcitrant macromolecular organic matter is decomposed into smaller molecules, carbon dioxide, and water, thus achieving the decomposition of recalcitrant organic matter in the wastewater.

[0009] Furthermore, wastewater undergoes continuous reactions in anaerobic, anoxic, and aerobic reactors to achieve nitrogen and phosphorus removal. In the anaerobic reactor, phosphorus is released and some organic matter is ammonified. In the anoxic and aerobic reactors, nitrite and nitrate gradually accumulate. After being irradiated by a 365nm wavelength ultraviolet irradiator, nitrite is catalyzed to generate hydroxyl radicals with strong oxidizing properties. Under the action of hydroxyl radicals, some recalcitrant large organic molecules are decomposed into small molecules, carbon dioxide, and water, thus achieving the decomposition of large organic molecules in wastewater. In the aerobic reactor, nitrifying bacteria use the organic matter in the wastewater as a nitrogen source. After completing the nitrification reaction, the generated nitrate nitrogen (NO3-N and NO2-N) is returned to the anoxic reactor through a mixed liquor reflux pump for denitrification treatment, reducing it to N2 and releasing it into the air. The remaining part is irradiated by a 254nm wavelength ultraviolet irradiator, which catalyzes nitrate to generate hydroxyl radicals, further decomposing recalcitrant organic matter. In the aerobic reactor, organic matter is biochemically degraded by microorganisms and continues to decrease. Organic nitrogen is nitrified and then nitrified by nitrifying bacteria, which significantly reduces the concentration of NH3-N. The nitrification process increases the concentration of NO3-N, and then the mixture is refluxed into the anoxic reactor for denitrification.

[0010] Furthermore, the temperature in the anoxic reactor is 5℃~30℃, which can be low temperature or room temperature. Under low temperature conditions, traditional processes are greatly affected by water temperature and have low low temperature treatment activity. Therefore, the present invention has a better effect on removing recalcitrant pollutants than traditional processes.

[0011] Furthermore, in the anoxic reactor, the pH value is controlled to be 7.5-9 by adding alkaline substances such as soda ash and CaO.

[0012] Furthermore, sulfur needs to be added to the anoxic reactor to promote the reduction of nitrate by nitrate-reducing bacteria.

[0013] Nitrate nitrogen generated by treatment with a 365nm wavelength ultraviolet irradiator is pumped to an anoxic reactor via a mixed liquor reflux pump. By controlling the temperature and pH value in the anoxic reactor and adding a substrate that promotes nitrate-reducing bacteria, nitrate reduction is enhanced while nitrite reduction is inhibited, thus achieving nitrite accumulation in the anoxic reactor and simultaneously completing the denitrification process.

[0014] Furthermore, the cylinders of the 365nm wavelength ultraviolet irradiator and the 254nm wavelength ultraviolet irradiator are made of 304 or 316 stainless steel, which can improve the reflectivity of ultraviolet rays, increase the radiation intensity, improve efficiency, and at the same time prevent sewage from corroding the inner wall and prevent the generation of secondary pollution.

[0015] Furthermore, the ultraviolet lamps of the 365nm wavelength ultraviolet irradiator and the 254nm wavelength ultraviolet irradiator are placed inside a quartz sleeve. A high-transmittance, high-purity quartz sleeve is selected to ensure that the ultraviolet transmittance is above 90%, reducing energy loss. The light intensity of the ultraviolet radiation is 10W~25W.

[0016] Furthermore, the ultraviolet lamps of the 365nm wavelength ultraviolet irradiator and the 254nm wavelength ultraviolet irradiator form an enclosing space, so that the radiation is uniform during the flow of sewage. The cleaning handle controls the sliding cleaning component to complete the cleaning of the lamp tube.

[0017] Furthermore, after treatment by the aforementioned system, the COD removal rate in the wastewater is 96.2%, the ammonia nitrogen removal rate is 88.4%, and the benzoic acid removal rate is 60%.

[0018] The present invention discloses the following technical effects:

[0019] This invention influences the growth of nitrifying and nitrifying bacteria by regulating various factors, thereby increasing and inhibiting nitrite reductase activity. This allows for the accumulation of nitrite and nitrate in both anoxic and aerobic reactors. Furthermore, under 365nm and 254nm ultraviolet irradiation, hydroxyl radicals are generated, efficiently degrading most organic pollutants in water, improving nitrogen and phosphorus removal, and enhancing water quality. Irradiation of nitrate-containing solutions with 254nm ultraviolet light generates various active components such as hydroxyl and nitrogen radicals, which effectively degrade organic pollutants in wastewater through hydrogen abstraction, addition, and electron transfer. Similarly, nitrite under 365nm ultraviolet light irradiation generates hydroxyl and nitrogen radicals, further degrading organic pollutants.

[0020] This invention is based on traditional A 2 Building upon the O process, this method utilizes the properties of 365nm and 254nm ultraviolet light to catalyze the production of highly oxidizing hydroxyl radicals from nitrites and nitrates accumulated in anoxic and aerobic reactors. This allows recalcitrant organic matter in wastewater to be decomposed into smaller molecules, carbon dioxide, and water through the ultraviolet irradiator, improving wastewater treatment efficiency. Simultaneously, the ultraviolet irradiator oxidizes nitrites and nitrates in the anoxic and aerobic reactors, promoting nitrification and denitrification, further enhancing nitrogen removal.

[0021] This invention utilizes an oxidation process to overcome the limitations of traditional A 2 The O process significantly reduces the degradation rate of COD and ammonia nitrogen at temperatures below 20°C, but it still maintains high efficiency at low temperatures (5°C~20°C).

[0022] This invention is commonly used in large-scale water plants in the A 2Creative adjustments and improvements were made to the O-process, eliminating the need to demolish and rebuild the original structure, thus saving costs. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a wastewater treatment system for recalcitrant organic matter.

[0025] Figure 2 This is a schematic diagram of an ultraviolet irradiator device.

[0026] Figure 3 The image shows the treatment effect of COD and ammonia nitrogen in the wastewater after treatment in Example 1.

[0027] Figure 4 The image shows the effect of treating benzoic acid in the wastewater after Example 1.

[0028] Symbol explanation:

[0029] 1-Anaerobic reactor inlet, 2-Anaerobic reactor, 3-Anoxic reactor, 4-Anoxic reactor outlet, 5-365nm wavelength ultraviolet irradiator inlet, 6-365nm wavelength ultraviolet lamp, 7-365nm wavelength ultraviolet irradiator, 8-365nm wavelength ultraviolet irradiator outlet, 9-Aerobic reactor inlet, 10-Aerobic reactor, 11-Mixed liquor reflux pump, 12-Aeration device, 13-Aerobic reactor outlet, 14-254nm wavelength ultraviolet irradiator inlet, 15-254nm wavelength ultraviolet lamp, 16-254nm wavelength ultraviolet irradiator, 17-254nm wavelength ultraviolet irradiator outlet.

[0030] 21-Irradiator inlet, 22-Quartz sleeve, 23-UV lamp, 24-Sliding cleaning component, 25-Irradiator outlet, 26-Cleaning handle, 27-Irradiator cylinder, 28-Irradiator controller. Detailed Implementation

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0033] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0034] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0035] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0036] The wastewater treatment system for recalcitrant organic matter in the embodiments of the present invention is as follows: Figure 1 As shown, the 365nm wavelength ultraviolet irradiator 7 is equipped with a 365nm wavelength ultraviolet lamp 6. The 254nm wavelength ultraviolet irradiator 16 is equipped with a 254nm wavelength ultraviolet lamp 15. An anoxic reactor 3 is provided on one side of the 365nm wavelength ultraviolet irradiator 7, and an aerobic reactor 10 is provided on the other side.

[0037] The anoxic reactor 3 is connected to the anaerobic reactor 2 via its outlet 4. The anaerobic reactor 3 is connected to the anaerobic reactor 2 on the other side. The anaerobic reactor 2 has its inlet 1 on the side furthest from the anoxic reactor 3.

[0038] The aerobic reactor 10 is connected to the outlet 8 of the 365nm wavelength ultraviolet irradiator via the aerobic reactor inlet 9. On the other side of the aerobic reactor 10, it is connected to the 254nm wavelength ultraviolet irradiator 16 via the aerobic reactor outlet 13 and the 254nm wavelength ultraviolet irradiator inlet 14. The 254nm wavelength ultraviolet irradiator 16 has an outlet 17 on its other side. An aeration device 12 and a mixed liquor return pump 11 are located at the bottom of the aerobic reactor 10.

[0039] The irradiator devices for the 365nm wavelength ultraviolet irradiator and the 254nm wavelength ultraviolet irradiator in the embodiments of the present invention are as follows: Figure 2 As shown, both the 365nm wavelength ultraviolet irradiator 7 and the 254nm wavelength ultraviolet irradiator 16 include: an irradiator inlet 21, a quartz sleeve 22, an ultraviolet lamp 23, a sliding cleaning component 24, an irradiator outlet 25, a cleaning handle 26, an irradiator cylinder 27, and an irradiator controller 28. The ultraviolet lamps of the 365nm wavelength ultraviolet irradiator 7 and the 254nm wavelength ultraviolet irradiator 16 form an enclosed space, ensuring uniform radiation as the wastewater flows through. The cleaning handle 26 controls the sliding cleaning component 24 to complete the cleaning of the lamp tubes.

[0040] In the embodiments of this invention, the COD concentration of the wastewater used was 500 mg / L, the ammonia nitrogen concentration was 50 mg / L, and the benzoic acid concentration was 10 mmol / L.

[0041] The technical solution of the present invention will be further illustrated by the following embodiments.

[0042] Example 1

[0043] Wastewater enters anaerobic reactor 2 from anaerobic reactor inlet 1, where phosphorus release and partial ammoniation of organic matter are completed. It then enters anoxic reactor 3, where the temperature is controlled at 20°C. Soda ash is added to adjust the pH to 7.5, and sulfur is added to promote nitrate reduction while inhibiting nitrite reduction, thus completing denitrification. The wastewater then enters 365nm ultraviolet irradiator 7 through anoxic reactor outlet 4 and 365nm wavelength ultraviolet irradiator inlet 5. After the reaction is completed in 365nm wavelength ultraviolet irradiator 7, the wastewater enters aerobic reactor 10 through 365nm wavelength ultraviolet irradiator outlet 8 and aerobic reactor inlet 9. Nitrification is completed there, with a portion returned to anoxic reactor 3 for denitrification, and the remainder flowing into 254nm wavelength ultraviolet irradiator 16. Under ultraviolet irradiation, nitrate ions generate hydroxyl radicals, which further decompose recalcitrant organic matter. In this embodiment, the cylinders of the 365nm wavelength ultraviolet irradiator 7 and the 254nm wavelength ultraviolet irradiator 16 are made of 304 stainless steel, and the light intensity of the ultraviolet radiation is 20W. The ultraviolet lamp is placed in a quartz sleeve, and the ultraviolet transmittance is 90%.

[0044] The final treatment results for COD and ammonia nitrogen in the effluent are shown in the image below. Figure 3 See the image for the benzoic acid treatment effect. Figure 4 The concentrations were as follows: COD 19.1 mg / L, ammonia nitrogen 5.8 mg / L, and benzoic acid 4.0 mmol / L. This represents a COD removal rate of 96.2%, an ammonia nitrogen removal rate of 88.4%, and a benzoic acid removal rate of 60%.

[0045] Example 2

[0046] Wastewater enters anaerobic reactor 2 from anaerobic reactor inlet 1, where phosphorus release and partial ammoniation of organic matter are completed. It then enters anoxic reactor 3, where the temperature is controlled at 30°C. CaO is added to adjust the pH to 8, and sulfur is added to promote nitrate reduction while inhibiting nitrite reduction, thus completing denitrification. The wastewater then enters 365nm ultraviolet irradiator 7 through anoxic reactor outlet 4 and 365nm wavelength ultraviolet irradiator inlet 5. After the reaction is completed in 365nm wavelength ultraviolet irradiator 7, the wastewater enters aerobic reactor 10 through 365nm wavelength ultraviolet irradiator outlet 8 and aerobic reactor inlet 9. Nitrification is completed there, with a portion returned to anoxic reactor 3 for denitrification, and the remainder flowing into 254nm wavelength ultraviolet irradiator 16. Under ultraviolet irradiation, nitrate ions generate hydroxyl radicals, which further decompose recalcitrant organic matter. In this embodiment, the cylinders of the 365nm wavelength ultraviolet irradiator 7 and the 254nm wavelength ultraviolet irradiator 16 are made of 304 stainless steel, the ultraviolet radiation intensity is 25W, the ultraviolet lamp is placed in a quartz sleeve, and the ultraviolet transmittance is 90%.

[0047] The final treated effluent showed a COD removal rate of 98.5%, an ammonia nitrogen removal rate of 90.2%, and a benzoic acid removal rate of 62%.

[0048] Example 3

[0049] Wastewater enters anaerobic reactor 2 from anaerobic reactor inlet 1, where phosphorus release and partial ammoniation of organic matter are completed. It then enters anoxic reactor 3, where the temperature is controlled at 15°C. Soda ash is added to adjust the pH to 9, and sulfur is added to promote nitrate reduction while inhibiting nitrite reduction, thus completing denitrification. The wastewater then enters 365nm ultraviolet irradiator 7 through anoxic reactor outlet 4 and 365nm wavelength ultraviolet irradiator inlet 5. After the reaction is completed in 365nm wavelength ultraviolet irradiator 7, the wastewater enters aerobic reactor 10 through 365nm wavelength ultraviolet irradiator outlet 8 and aerobic reactor inlet 9. Nitrification is completed there, with a portion returned to anoxic reactor 3 for denitrification, and the remainder flowing into 254nm wavelength ultraviolet irradiator 16. Under ultraviolet irradiation, nitrate ions generate hydroxyl radicals, which further decompose recalcitrant organic matter. In the embodiment, the cylinders of the 365nm wavelength ultraviolet irradiator 7 and the 254nm wavelength ultraviolet irradiator 16 are made of 316 stainless steel, the light intensity of the ultraviolet radiation is 10W, the ultraviolet lamp is placed in a quartz sleeve, and the ultraviolet transmittance is 90%.

[0050] The final treated COD removal rate was 93.4%, ammonia nitrogen removal rate was 89.2%, and benzoic acid removal rate was 72%.

[0051] Example 4

[0052] Wastewater enters anaerobic reactor 2 from anaerobic reactor inlet 1, where phosphorus release and partial ammoniation of organic matter are completed. It then enters anoxic reactor 3, where the temperature is controlled at 5°C. Pure CaO is added to adjust the pH to 8, and sulfur is added to promote nitrate reduction while inhibiting nitrite reduction, thus completing denitrification. The wastewater then enters 365nm ultraviolet irradiator 7 through anoxic reactor outlet 4 and 365nm wavelength ultraviolet irradiator inlet 5. After the reaction is completed in 365nm wavelength ultraviolet irradiator 7, the wastewater enters aerobic reactor 10 through 365nm wavelength ultraviolet irradiator outlet 8 and aerobic reactor inlet 9. Nitrification is completed there, with a portion returned to anoxic reactor 3 for denitrification, and the remainder flowing into 254nm wavelength ultraviolet irradiator 16. Under ultraviolet irradiation, nitrate ions generate hydroxyl radicals, which further decompose recalcitrant organic matter. In the embodiment, the cylinders of the 365nm wavelength ultraviolet irradiator 7 and the 254nm wavelength ultraviolet irradiator 16 are made of 304 stainless steel, the light intensity of the ultraviolet radiation is 20W, the ultraviolet lamp is placed in a quartz sleeve, and the ultraviolet transmittance is 90%.

[0053] The final treated COD removal rate was 95.8%, ammonia nitrogen removal rate was 88.7%, and benzoic acid removal rate was 68%.

[0054] Comparative Example 1

[0055] Same as Example 1, except that the process no longer promotes nitrite accumulation, and no additional substances such as sulfur that promote nitrite accumulation are added. COD removal rate: 90.86%, ammonia nitrogen removal rate: 79.92%, benzoic acid removal rate: 49.1%.

[0056] Comparative Example 2

[0057] Same as Example 1, except that the 365nm wavelength ultraviolet irradiator 7 was turned off. COD removal rate was 90.21%, ammonia nitrogen removal rate was 79.46%, and benzoic acid removal rate was 48.8%.

[0058] Comparative Example 3

[0059] Same as Example 1, except that the 254nm wavelength ultraviolet irradiator 16 was turned off. COD removal rate was 91.32%, ammonia nitrogen removal rate was 82.12%, and benzoic acid removal rate was 50%.

[0060] Comparative Example 4

[0061] Same as Example 1, except that the intensity of the ultraviolet radiation from the 365nm wavelength ultraviolet irradiator 7 and the 254nm wavelength ultraviolet irradiator 16 is 10W. The COD removal rate is 92.12%, the ammonia nitrogen removal rate is 82.40%, and the benzoic acid removal rate is 51.21%.

[0062] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A system for treating recalcitrant organic matter in wastewater, characterized in that, The system for treating the refractory organic matter in the sewage comprises an anaerobic reactor (2), an anoxic reactor (3), an aerobic reactor (10), a 365nm wavelength ultraviolet irradiation device (7) and a 254nm wavelength ultraviolet irradiation device (16); The 365nm wavelength ultraviolet irradiation device (7) is provided with a 365nm wavelength ultraviolet lamp (6); the 254nm wavelength ultraviolet irradiation device (16) is provided with a 254nm wavelength ultraviolet lamp (15); the light intensity of the ultraviolet radiation in the 365nm wavelength ultraviolet irradiation device (7) and the 254nm wavelength ultraviolet irradiation device (16) is 10W~25W; the 365nm wavelength ultraviolet lamp (6) and the 254nm wavelength ultraviolet lamp (15) are both placed in a quartz sleeve, and the ultraviolet transmittance is 90%; The 365nm wavelength ultraviolet irradiation device (7) and the 254nm wavelength ultraviolet irradiation device (16) both comprise a water inlet (21), a quartz sleeve (22), an ultraviolet lamp (23), a sliding cleaning component (24), a water outlet (25), a cleaning handle (26), a cylinder body (27) and a controller (28); The ultraviolet lamps of the 365nm wavelength ultraviolet irradiation device (7) and the 254nm wavelength ultraviolet irradiation device (16) form a surrounding space, so that the sewage is uniformly irradiated during flowing, and the cleaning handle (26) is used to control the sliding cleaning component (24) to complete the cleaning work of the lamp tube; One side of the anaerobic reactor (2) is provided with an anaerobic reactor water inlet (1); the other side of the anaerobic reactor (2) is connected with one side of the anoxic reactor (3); the other side of the anoxic reactor (3) is communicated with the 365nm wavelength ultraviolet irradiation device (7) through an anoxic reactor water outlet (4) and a 365nm wavelength ultraviolet irradiation device water inlet (5); the temperature in the anoxic reactor (3) is 5℃~30℃; the pH value in the anoxic reactor (3) is 7.5~9.0; One side of the aerobic reactor (10) is communicated with the 365nm wavelength ultraviolet irradiation device water outlet (8) through an aerobic reactor water inlet (9), and the other side of the aerobic reactor (10) is communicated with one side of the 254nm wavelength ultraviolet irradiation device (16) through an aerobic reactor water outlet (13) and a 254nm wavelength ultraviolet irradiation device water inlet (14); the other side of the 254nm wavelength ultraviolet irradiation device (16) is provided with a 254nm wavelength ultraviolet irradiation device water outlet (17); the bottom of the aerobic reactor (10) is provided with an aeration device (12) and a mixed liquid reflux pump (11); Sewage enters the anaerobic reactor (2) from the water inlet (1) of the anaerobic reactor (2), and the release of phosphorus and the ammoniation of part of the organic matter are completed in the anaerobic reactor (2), and then the sewage enters the anoxic reactor (3), and sulfur is added in the anoxic reactor (3) to promote the reduction of nitrate and inhibit the reduction of nitrite, complete the denitrification treatment, and then the sewage enters the 365nm wavelength ultraviolet irradiation device (7) for ultraviolet irradiation, so that the nitrite is catalyzed to generate hydroxyl radicals with strong oxidizing property, and under the action of the hydroxyl radicals, part of the refractory macromolecular organic matter is decomposed into small molecular substances, carbon dioxide and water, realizing the decomposition of macromolecular organic matter in the sewage, and then the sewage enters the aerobic reactor (10), and the nitrite and nitrate are gradually accumulated in the anoxic reactor (3) and the aerobic reactor (10), in the aerobic reactor (10), the nitrifying bacteria use the organic matter in the sewage as a nitrogen source, and after the nitrification reaction is completed, part of the sewage is refluxed into the anoxic reactor (3) for denitrification treatment, and the remaining part flows into the 254nm wavelength ultraviolet irradiation device (16) for ultraviolet irradiation, so that the nitrate is catalyzed to generate hydroxyl radicals, and under the action of the hydroxyl radicals, the refractory organic matter is continuously decomposed.

2. The system for treating recalcitrant organics in wastewater of claim 1, wherein, The barrel of the 365nm wavelength ultraviolet irradiation device (7) and the 254nm wavelength ultraviolet irradiation device (16) is made of 304 or 316 stainless steel.

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