Acetonitrile-containing industrial wastewater treatment system

Abstract

The utility model discloses an acetonitrile-containing industrial wastewater treatment system and relates to the technical field of wastewater treatment. According to the technical scheme, the system comprises a steam stripping device, a regulating tank, a hydrolysis acidification tank, an IC anaerobic reactor, an aerobic decarbonization tank, a sedimentation tank, an anoxic tank I, an aerobic denitrification tank I, an anoxic tank II, an aerobic denitrification tank II, a secondary sedimentation tank and a deep treatment tank which are connected in sequence, the regulating tank, the hydrolysis acidification tank, the aerobic decarbonization tank, the aerobic denitrification tank I, the aerobic denitrification tank II and the deep treatment tank are respectively provided with an aeration device, and the deep treatment tank is provided with a strong oxidant adding device. According to the utility model, the steam stripping decyanation is realized by utilizing the steam stripping device, and the decomposition of pollution factors such as acetonitrile and the like is promoted and the release of organic nitrogen is promoted through a high-efficiency hydrolytic acidification process; a secondary anoxic / aerobic system is added, so that the total nitrogen removal capability of the system is enhanced; the deep oxidation decyanation unit is added, so that cyanide in discharged water is deeply treated, and the discharged water is ensured to be qualified.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment, in particular to a system for treating industrial wastewater containing acetonitrile. Background Art

[0002] A chemical plant produced a high-concentration wastewater during its production process. During the initial testing process, it was found that the ammonia nitrogen content in the high-concentration wastewater discharged by the chemical plant was at an average level and did not significantly exceed the normal range. However, the organic nitrogen content was abnormally high. In order to further explore the reasons for the high organic nitrogen content, technicians referred to the water quality data of similar products and conducted a detailed water quality analysis based on the chemical plant's own production process and raw material usage. After a series of scientific and rigorous experiments and comparisons, it was finally determined that the organic nitrogen in this high-concentration wastewater mainly came from acetonitrile. Acetonitrile, with the chemical formula CH3CN, is an organic solvent widely used in chemical production, and the cyanide (CN-) it contains is the key factor that leads to the abnormal increase in organic nitrogen content.

[0003] The cyanide in acetonitrile is not only a significant component of organic nitrogen but, more importantly, is itself highly toxic, posing a potential threat to both humans and the environment. Cyanide can bind tightly to cytochrome oxidase in the human body, blocking the cell's respiratory chain and causing poisoning or even death. Therefore, if this high-concentration wastewater containing high concentrations of acetonitrile and its toxic cyanide is discharged directly without proper treatment, it will pose a serious threat to the surrounding ecological environment and the health of residents.

[0004] In view of this serious situation, chemical plants must take immediate measures to effectively remove acetonitrile and its cyanide from wastewater, ensuring that the wastewater meets national and local environmental protection standards before discharge to maintain the safety of the ecological environment and human health. Utility Model Content

[0005] The technical problem to be solved by the utility model is: to overcome the deficiencies of the existing technology and provide an acetonitrile-containing industrial wastewater treatment system, which utilizes a stripping device to achieve stripping and decyanation, promotes the decomposition of acetonitrile and other polluting factors and the release of organic nitrogen through a high-efficiency hydrolysis and acidification process; adds a secondary anoxic / aerobic system to enhance the system's ability to remove total nitrogen; and adds a deep oxidation and decyanation unit to deeply treat cyanide in external drainage to ensure that the effluent is qualified.

[0006] The technical solution of the utility model is:

[0007] The acetonitrile-containing industrial wastewater treatment system includes a stripping device, a regulating tank, a hydrolysis acidification tank, an IC anaerobic reactor, an aerobic decarbonization tank, a sedimentation tank, an anoxic tank 1, an aerobic denitrification tank 1, anoxic tank 2, an aerobic denitrification tank 2, a secondary sedimentation tank and a deep treatment tank, which are connected in sequence. The regulating tank, the hydrolysis acidification tank, the aerobic decarbonization tank, the aerobic denitrification tank 1, the aerobic denitrification tank 2 and the deep treatment tank are respectively provided with an aeration device, and the deep treatment tank is provided with a strong oxidant dosing device.

[0008] Preferably, the stripping device is an evaporator or a stripping tower.

[0009] Preferably, the stripping device is connected to a spray tower via a gas discharge pipe.

[0010] Preferably, the stripping device is provided with a liquid alkali dosing device; the anoxic tank 1 and the anoxic tank 2 are respectively provided with a carbon source dosing device; the aerobic denitrification tank 1 and the aerobic denitrification tank 2 are respectively provided with an alkali dosing device.

[0011] Preferably, a flow meter and a regulating valve are provided on the water inlet pipe of the regulating tank, and a liquid level meter is provided in the regulating tank.

[0012] Preferably, the aeration devices of the regulating tank, hydrolysis acidification tank and deep treatment tank adopt perforated aeration pipes; the aeration devices of the aerobic decarbonization tank, aerobic denitrification tank 1 and aerobic denitrification tank 2 adopt microporous aeration heads.

[0013] Preferably, a filler bracket is provided on the perforated aeration pipe of the hydrolysis acidification tank, and volcanic rock glass ball fillers are provided on the filler bracket.

[0014] Preferably, a flow meter and a regulating valve are provided on the water inlet pipe of the hydrolysis acidification tank, and a reflux pump is provided in the hydrolysis acidification tank; the sedimentation tank is connected to the aerobic decarbonization tank through a sludge return pipe, and a sludge return pump and a sludge flow meter are provided on the sludge return pipe; the aerobic denitrification tank 1 and the aerobic denitrification tank 2 are respectively provided with a reflux pump and a flow meter; the second sedimentation tank is connected to the anoxic tank 1 through a sludge return pipe, and a sludge return pump and a sludge flow meter are provided on the sludge return pipe.

[0015] Preferably, a sludge scraper is provided in the secondary sedimentation tank.

[0016] Preferably, the hydrolysis acidification tank and the deep treatment tank are respectively provided with a glass fiber reinforced plastic gas collecting hood; the anoxic tank 1 and the anoxic tank 2 are respectively provided with a submersible mixer.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In response to high-concentration industrial wastewater rich in acetonitrile, cyanide, etc., the utility model proposes a pretreatment scheme that fully utilizes the high water temperature generated by the stripping device to achieve stripping and decyanation, and is equipped with alkaline solution spray absorption; fully utilizes the existing biochemical treatment system, and while retaining the tank capacity and fully utilizing it, improves the treatment capacity of the original treatment facilities and increases the pollutant removal load, including COD load, ammonia nitrogen load, and total nitrogen load; adds necessary links, such as the front-end high-efficiency hydrolysis and acidification process, to promote the decomposition of pollutants such as acetonitrile and the release of organic nitrogen; adds a secondary anoxic / aerobic (A2 / O2) system to enhance the system's ability to remove total nitrogen; adds a deep oxidation decyanation unit to deeply treat the cyanide in the external discharge to ensure that the effluent is qualified. The utility model's acetonitrile-containing industrial wastewater treatment system effectively removes acetonitrile and its cyanide in the wastewater, ensuring that the wastewater meets national and local environmental protection standards before discharge, thereby maintaining the safety of the ecological environment and human health. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of an acetonitrile-containing industrial wastewater treatment system of the present invention.

[0020] In the figure, 1. Steam stripping device; 2. Equalization tank; 3. Hydrolysis acidification tank; 4. IC anaerobic reactor; 5. Aerobic decarbonization tank; 6. Sedimentation tank; 7. Anoxic tank 1; 8. Aerobic denitrification tank 1; 9. Anoxic tank 2; 10. Aerobic denitrification tank 2; 11. Secondary sedimentation tank; 12. Deep treatment tank; 13. Spray tower; 14. Liquid alkali dosing tank; 15. Carbon source dosing tank; 16. Strong oxidant dosing tank; 17. Liquid level meter; 18. Sludge return pump; 19. Flow meter; 20. Lifting pump; 21. Control valve; 22. Metering pump; 23. Sludge flow meter. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0022] Example 1

[0023] like Figure 1 As shown, this embodiment provides an acetonitrile-containing industrial wastewater treatment system, comprising a stripping device 1, a biochemical treatment unit, and a deep treatment tank 12 connected in sequence, wherein the biochemical treatment unit comprises a regulating tank 2, a hydrolysis and acidification tank 3, an IC anaerobic reactor 4, an aerobic decarbonization tank 5, a sedimentation tank 6, an anoxic tank 1 7, an aerobic denitrification tank 1 8, anoxic tank 2 9, an aerobic denitrification tank 2 10, and a secondary sedimentation tank 11 connected in sequence. The specific process of each step is as follows:

[0024] (1) Preprocessing

[0025] 1) Stripping and denitrification

[0026] An evaporator or a reused / newly added stripping tower is used to pretreat industrial wastewater containing high-concentration acetonitrile. Taking advantage of the acidic hydrolysis of acetonitrile in water and the volatilization of hydrogen cyanide and carboxylic acid, stripping is performed to remove 70-80% of the total nitrogen. The volatilized hydrogen cyanide enters the spray tower 13 through a gas discharge pipe, and the spray tower 13 sprays alkaline solution to absorb the gas.

[0027] 2) pH adjustment

[0028] The evaporator or stripping tower is equipped with a liquid caustic soda dosing device, comprising a liquid caustic soda dosing tank 14 connected to the evaporator or stripping tower via a pipeline, with a metering pump 22 installed on the pipeline. Because the raw water is highly acidic, the high-concentration wastewater from the stripping pretreatment is directly dosed with 30% liquid caustic soda in the evaporator or stripping tower after the reaction is complete, adjusting the pH to 5.5-6. The wastewater is then pumped to the regulating tank 2 via a lift pump 20.

[0029] (2) Biochemical treatment unit

[0030] 1) Equalization tank 2

[0031] Equalization Tank 2 overcomes the unevenness of mixed wastewater discharge, evenly regulating variations in wastewater quality and quantity over time, storing surpluses and replenishing shortages to ensure uniform water flow to subsequent biochemical treatment units, thereby reducing the impact of unstable wastewater concentrations on subsequent treatment facilities. Perforated aeration pipes are installed within Equalization Tank 2 for aeration and stirring, ensuring uniform mixing of the incoming water. This ensures more uniform quality of wastewater entering the biochemical treatment units and avoids significant fluctuations in influent water quality.

[0032] A flow meter 19 and a regulating valve 21 are provided on the water inlet pipe of the regulating tank 2 , and a liquid level meter 17 is provided in the regulating tank 2 to adjust the water inlet of the regulating tank 2 according to the liquid level of the regulating tank 2 .

[0033] The effluent from the regulating tank 2 enters the subsequent biochemical treatment unit through the lifting pump 20. At the same time, the alkalinity of part of the effluent from the subsequent secondary sedimentation tank 11 is returned to the regulating tank 2 to neutralize part of the acidity to reduce the use of liquid alkali.

[0034] 2) Hydrolysis acidification tank 3 (fixed bed process)

[0035] After thorough mixing, the wastewater from equalization tank 2 enters hydrolysis and acidification tank 3 via lift pump 20 for hydrolysis and biochemical reactions. Hydrolysis and acidification tank 3 utilizes fixed-bed technology, utilizing fixed-bed packing. The lower equipment utilizes 304 perforated aeration tubes, topped with volcanic rock glass balls, which occupy 35% of the tank volume. (The perforated aeration tubes in hydrolysis and acidification tank 3 are equipped with fiberglass grid packing supports, and the volcanic rock glass balls are mounted on the packing supports.) Micro-aeration is achieved within hydrolysis and acidification tank 3 through the perforated aeration tubes, maintaining a DO level of 0.2-0.5 mg / L. A recirculation pump is installed within hydrolysis and acidification tank 3 to promote internal circulation, increase contact between wastewater and microorganisms, improve organic matter removal efficiency, maintain water circulation within the tank, and prevent sludge sedimentation. A flowmeter 19 and a regulating valve 21 are installed on the inlet pipe of hydrolysis and acidification tank 3 to control the inlet flow. A fiberglass gas hood is installed on the top of hydrolysis and acidification tank 3 to prevent the spread of exhaust gases generated during the wastewater treatment process.

[0036] Fixed-bed treatment focuses primarily on the first and second anaerobic stages, primarily hydrolysis, hydrogenation, and acidification. Anaerobic microorganisms have a different metabolic process than aerobic microorganisms for the cleavage of rings in heterocyclic compounds and polycyclic aromatic hydrocarbons, with both reductive and non-reductive cleavage. The primary goal of anaerobic biochemical treatment is to improve the biodegradability of wastewater and reduce COD to a certain extent. It is ideally suited for the hydrolysis of large amounts of acetonitrile molecules in wastewater, releasing organic nitrogen into ammoniacal nitrogen.

[0037] Technical advantages of the hydrolysis and acidification end after transformation:

[0038] (1) Improvement of removal load: The anaerobic tank is transformed into a hydrolysis acidification fixed bed process. On the basis of retaining the traditional hydrolysis acidification ring breaking process, the COD removal capacity is enhanced. It is expected to increase the COD removal load by more than 50%, from 0.2-0.3 kgCOD / m 3 ·d increased to 0.5-0.8kgCOD / m 3 ·d.

[0039] (2) Enhanced shock resistance: Common pollutants in pharmaceutical wastewater, such as organic solvents such as acetonitrile, toluene, and aniline, often have fatal effects on traditional biochemical treatment. However, fixed anaerobic bed technology has a longer sludge age and is not easily affected by shock and flocculent disintegration, which is very effective in adapting to the shock of high-concentration sewage.

[0040] 3) IC anaerobic reactor 4

[0041] The effluent from the hydrolysis and acidification tank 3 flows by gravity into the IC anaerobic reactor 4. The IC anaerobic reactor 4 is a highly efficient, multi-stage, internally circulating anaerobic reactor characterized by a small footprint, high organic loading, strong shock resistance, stable performance, and simplified operation and management. Its internal structure resembles two UASB reactors connected in series, consisting of two anaerobic reactors, one above the other. Wastewater flows upward through the IC anaerobic reactor 4, where pollutants are adsorbed and degraded by bacteria. Purified water then flows out from the top of the IC anaerobic reactor 4.

[0042] Technical advantages of IC anaerobic reactor 4:

[0043] (1) High volumetric loading rate: Due to the existence of internal circulation, the mass transfer effect is good, the biomass is large, and the sludge age is long. The volumetric loading rate of the IC anaerobic reactor 4 is about 3 times higher than that of the ordinary UASB reactor.

[0044] (2) Saving infrastructure investment and floor space: The high volumetric loading rate makes the volume of the IC anaerobic reactor 4 approximately 1 / 4-1 / 3 of that of an ordinary UASB reactor, thereby reducing infrastructure investment; at the same time, due to its large height-to-diameter ratio and small floor space, it is suitable for the current problem of limited on-site land.

[0045] (3) Low operating cost: The IC anaerobic reactor 4 uses the biogas generated by itself as power to achieve internal circulation and does not require external power, so the operating cost is low.

[0046] (4) Strong shock load resistance: The internal circulation enables the IC anaerobic reactor 4 to have a strong shock load resistance when treating low-concentration and high-concentration organic wastewater.

[0047] (5) Ability to buffer pH: The internal circulation flow can flow back to the first-stage anaerobic effluent, and the alkalinity converted from COD can be used to buffer the pH and maintain the stability of the pH in the reactor.

[0048] (6) Good effluent stability: The IC anaerobic reactor 4 is equivalent to two UASB reactors running in series. The lower UASB reactor has a high organic loading rate, while the upper UASB reactor has a lower loading rate. This design makes the effluent stable.

[0049] (7) Strong resistance to low temperature: Since it contains a large number of microorganisms, the IC anaerobic reactor 4 can also operate effectively under normal temperature conditions, reducing the difficulty of digestion and heat preservation.

[0050] (8) Short startup cycle: The sludge activity in the IC anaerobic reactor 4 is high, the biological proliferation is fast, and the startup cycle is short, generally 1-2 months. Compared with the 4-6 month startup cycle of the ordinary UASB reactor, the IC anaerobic reactor 4 is faster and more efficient.

[0051] 4) Aerobic decarbonization pool 5

[0052] The effluent from the IC anaerobic reactor 4 flows by gravity into the aerobic decarbonization tank 5. The aerobic decarbonization tank 5 is equipped with a microporous aeration head. Roots blowers are used to aerate the aerobic sludge in the tank to keep it in suspension. COD removal is the primary task, and aerobic decarbonization bacteria are cultivated as the dominant species.

[0053] 5) Sedimentation tank 6

[0054] The aerobic decarbonization tank 5 is connected to the sedimentation tank 6 through an outlet pipe, and the sedimentation tank 6 is connected to the aerobic decarbonization tank 5 through a sludge return pipe. The sludge return pipe is provided with a sludge return pump 18 and a sludge flow meter 23 to return the sludge at the bottom of the sedimentation tank 6 to the aerobic decarbonization tank 5 to replenish the sludge concentration.

[0055] 6) Anoxic pool 7

[0056] Bacteria in the anoxic tank 7 reduce nitrate under anoxic conditions, releasing molecular nitrogen or N2O. Microorganisms use NO2 - and NO3 - As the final electron acceptor of respiration, it reduces nitric acid to nitrogen: NO3 - →NO2 - →N2↑. The primary purpose of biochemical treatment in Anoxic Tank 7 is to remove ammonia nitrogen and simultaneously degrade other pollutants in the water. A submersible mixer is installed to ensure thorough mixing and reaction between the sludge and water within the tank, preventing excessive sludge from settling to the bottom and causing poor operational performance. Anoxic Tank 7 is equipped with a carbon source dosing device, comprising a carbon source dosing tank 15 connected to Anoxic Tank 7 via a pipeline. A metering pump 22 is installed on the pipeline. The added carbon source is primarily organic matter, including methanol, ethanol, acetic acid, glucose, and the like. Adding a carbon source to Anoxic Tank 7 promotes the growth and reproduction of microorganisms and accelerates the decomposition and removal of organic matter.

[0057] 7) Aerobic denitrification pool 8

[0058] The effluent from the anoxic tank 7 flows by gravity into the aerobic denitrification tank 8. A microporous aeration head is installed in the tank, and a Roots blower is used to aerate the aerobic sludge in the tank to keep it in a suspended state. Furthermore, the aerobic denitrification tank 8 is equipped with a return pump and flow meter 19, which increases the return ratio to 400%, thereby increasing the biomass and nitrifying bacteria, enhancing the nitrification process and the utilization rate of organic carbon sources, and further improving TN and NH. 3- The removal rate of N. The aerobic denitrification tank 8 is equipped with a liquid alkali dosing device like the stripping device 1.

[0059] 8) Anoxic Pool 29

[0060] The bacteria in the anoxic tank 29 reduce nitrates under anoxic conditions, releasing molecular nitrogen or N2O. Microorganisms use NO2 -and NO3 - As the final electron acceptor of respiration, it reduces nitric acid to nitrogen: NO3 - →NO2 - →N2↑. The primary purpose of biochemical treatment in Anoxic Tank 29 is to remove ammonia nitrogen and simultaneously degrade other pollutants in the water. A submersible mixer ensures thorough mixing and reaction between the sludge and water within the tank, preventing excessive sludge from settling and causing poor operational performance. Like Anoxic Tank 17, Anoxic Tank 29 is equipped with a carbon source dosing device.

[0061] 9) Aerobic denitrification pool 210

[0062] The effluent from the anoxic tank 29 flows by gravity into the aerobic denitrification tank 210. A microporous aeration head is installed in the tank, and a Roots blower is used to aerate the aerobic sludge in the tank to keep it in a suspended state. Furthermore, the aerobic denitrification tank 210 is equipped with a return pump and flow meter 19, which increases the return ratio to 400%, thereby increasing the biomass and nitrifying bacteria, enhancing the nitrification process and the utilization rate of organic carbon sources, and further improving TN and NH. 3- The removal rate of N. The aerobic denitrification tank 2 10 is provided with a liquid alkali dosing device like the stripping device 1.

[0063] 10) Secondary sedimentation tank 11

[0064] The effluent from aerobic denitrification tank 2 (10) flows by gravity into the secondary sedimentation tank (11) for sludge sedimentation. A sludge scraper is installed within the tank to scrape sludge from the surface, allowing it to settle to the bottom, facilitating collection and discharge. The secondary sedimentation tank (11) is connected to the anoxic tank (7) via a sludge return pipe, equipped with a sludge return pump (18) and a sludge flowmeter (23). The sludge return pump (18) pumps some of the sludge that settles at the bottom of the secondary sedimentation tank (11) into the anoxic tank (7) and subsequent biochemical tanks, replenishing the biochemical tanks. The remaining sludge is treated as residual sludge and then enters the subsequent sludge treatment units.

[0065] (3) Deep processing

[0066] After effluent from the secondary settling tank 11 flows by gravity into the advanced treatment tank 12, which is equipped with perforated aeration pipes and aerated by a Roots blower. A strong oxidant dosing device is also provided. This device includes a strong oxidant dosing tank 16 connected to the secondary settling tank 11 via a pipeline equipped with a metering pump 22. Sodium hypochlorite is added to the tank through the strong oxidant dosing device to perform advanced treatment on the wastewater, ensuring that the effluent meets discharge standards. A fiberglass gas hood is installed on the top of the advanced treatment tank 12 to prevent the spread of generated exhaust gases.

Claims

1. An acetonitrile-containing industrial wastewater treatment system, characterized in that: The invention comprises a stripping device (1), a regulating tank (2), a hydrolysis and acidification tank (3), an IC anaerobic reactor (4), an aerobic decarbonization tank (5), a sedimentation tank (6), an anoxic tank 1 (7), an aerobic denitrification tank 1 (8), anoxic tank 2 (9), an aerobic denitrification tank 2 (10), a secondary sedimentation tank (11) and a deep treatment tank (12) which are connected in sequence. The regulating tank (2), the hydrolysis and acidification tank (3), the aerobic decarbonization tank (5), the aerobic denitrification tank 1 (8), the aerobic denitrification tank 2 (10) and the deep treatment tank (12) are respectively provided with an aeration device, and the deep treatment tank (12) is provided with a strong oxidant dosing device.

2. The acetonitrile-containing industrial wastewater treatment system according to claim 1, wherein The stripping device (1) adopts an evaporator or a stripping tower.

3. The acetonitrile-containing industrial wastewater treatment system according to claim 1, wherein The stripping device (1) is connected to a spray tower (13) via a gas discharge pipe.

4. The acetonitrile-containing industrial wastewater treatment system according to claim 1, wherein The stripping device (1) is provided with a liquid alkali dosing device; the anoxic tank 1 (7) and the anoxic tank 2 (9) are respectively provided with a carbon source dosing device; the aerobic denitrification tank 1 (8) and the aerobic denitrification tank 2 (10) are respectively provided with an alkali dosing device.

5. The acetonitrile-containing industrial wastewater treatment system according to claim 1, wherein A flow meter (19) and a regulating valve (21) are provided on the water inlet pipe of the regulating tank (2), and a liquid level meter (17) is provided in the regulating tank (2).

6. The acetonitrile-containing industrial wastewater treatment system according to claim 1, wherein The aeration devices of the regulating tank (2), hydrolysis acidification tank (3) and deep treatment tank (12) adopt perforated aeration pipes; the aeration devices of the aerobic decarbonization tank (5), aerobic denitrification tank 1 (8) and aerobic denitrification tank 2 (10) adopt microporous aeration heads.

7. The acetonitrile-containing industrial wastewater treatment system according to claim 6, wherein: A filler support is provided on the perforated aeration pipe of the hydrolysis acidification tank (3), and volcanic rock glass ball fillers are provided on the filler support.

8. The acetonitrile-containing industrial wastewater treatment system according to claim 1, wherein The water inlet pipe of the hydrolysis acidification tank (3) is provided with a flow meter (19) and a regulating valve (21), and a reflux pump is provided in the hydrolysis acidification tank (3); the sedimentation tank (6) is connected to the aerobic decarbonization tank (5) through a sludge reflux pipe, and a sludge reflux pump (18) and a sludge flow meter (23) are provided on the sludge reflux pipe; the aerobic denitrification tank 1 (8) and the aerobic denitrification tank 2 (10) are provided with a reflux pump and a flow meter (19) respectively; the secondary sedimentation tank (11) is connected to the anoxic tank 1 (7) through a sludge reflux pipe, and a sludge reflux pump (18) and a sludge flow meter (23) are provided on the sludge reflux pipe.

9. The acetonitrile-containing industrial wastewater treatment system according to claim 1, wherein: A mud scraper is provided in the secondary sedimentation tank (11).

10. The acetonitrile-containing industrial wastewater treatment system according to claim 1, wherein: The hydrolysis and acidification tank (3) and the deep treatment tank (12) are respectively provided with glass fiber reinforced plastic gas collecting hoods; the anoxic tank 1 (7) and the anoxic tank 2 (9) are respectively provided with submersible mixers.

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