Method and device for treating wastewater containing chlorobenzene and acetone

Abstract

The invention discloses a method and a device for treating wastewater containing chlorobenzene and acetone, and belongs to the technical field of wastewater treatment. The treatment method comprises the following steps: 1) homogenizing treatment; 2) primary oxidation; 3) recovering acetone and recycling an oxidizing agent; 4) secondary oxidation; (5) recycling drained water; the device comprises a homogenizing tank, a first-stage photocatalytic oxidation tank, a second-stage photocatalytic oxidation tank and a monitoring pool which are sequentially connected through pipelines, the homogenizing tank is provided with a wastewater inlet pipeline, the first-stage photocatalytic oxidation tank is provided with an ozone inlet pipeline, a first ultraviolet circulation pipeline and a gas exhaust pipeline, the gas exhaust pipeline is connected with a condensation tank, and the condensation tank is connected with a water inlet pipeline. The second-stage photocatalytic oxidation tank is provided with an ultraviolet circulation pipeline II and a fresh ozone inlet pipeline, and the ultraviolet circulation pipeline II is provided with an ultraviolet reactor II. The invention provides a method and a device for treating wastewater containing chlorobenzene and acetone, which have the advantages of repeated use of an oxidant, recycling of acetone and lower operation cost.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method and a device for treating wastewater containing chlorobenzene and acetone. Background Art

[0002] The chemical industry widely uses chlorobenzene and acetone as production solvents, which in turn produces wastewater containing chlorobenzene and acetone, which is one of the most difficult industrial wastewaters to treat. Chlorobenzene pollutants in this type of wastewater will inhibit microorganisms, and the presence of acetone will cause the COD content to far exceed the emission standards, requiring pretreatment through an oxidation process to achieve standard emissions.

[0003] Photocatalytic oxidation has the advantages of strong oxidation ability and high oxidation efficiency. It is often used in industry to treat this type of wastewater. Using hydrogen peroxide as the oxidant, the hydroxyl radicals produced in the reaction attack the excited organic molecules to achieve deep degradation of chlorobenzene and acetone. The effluent COD content is <30mg / L, reaching the direct discharge standard. However, the oxidation reaction time is long when photocatalytic oxidation is used to treat chlorobenzene and acetone-containing wastewater at the same time, and the dosage of oxidant and catalyst is large; and each chemical park has a supporting sewage treatment plant that can treat mixed wastewater containing COD200-600mg / L. Therefore, the economic efficiency of treating wastewater to the direct discharge standard using photocatalytic oxidation technology is poor, and the operating cost is high.

[0004] Another common photocatalytic oxidant is ozone. Compared with hydrogen peroxide, ozone is easy to prepare and widely used in wastewater treatment. However, ozone gas has low solubility in water, low oxidation energy, incomplete degradation of organic matter, and insufficient capacity to treat wastewater containing chlorobenzene and acetone.

[0005] Patent CN112028403A discloses a method and system for treating wastewater containing phenol and acetone, including: a preparation unit, an SMBR unit and an ozone biochemical unit, and the wastewater to be treated flows through the preparation unit, the SMBR unit, the ozone catalytic oxidation unit and the biochemical unit in sequence. The method uses biological methods and ozone catalytic methods to treat phenol and acetone wastewater, but is not suitable for wastewater containing chlorobenzene at the same time, because chlorobenzene has biological inhibition, which will reduce the efficiency of biochemical reactions and thus affect the biochemical treatment effect of wastewater.

[0006] Patent CN104944656A discloses a method and device for pre-treating high-concentration wastewater by ultraviolet-ozone synergistic oxidation, including: the high-concentration wastewater in the raw water tank is mixed with ozone to obtain milky white effluent containing ozone microbubbles, which then enters a reaction tank provided with a vertical partition, wherein the vertical partition divides the reaction tank into an inlet side and an outlet side, sulfuric acid and hydrogen peroxide are added to the inlet side of the reaction tank, and organic pollutants are degraded under the combined action of ozone and hydrogen peroxide; a part of the effluent at the lower part of the outlet side of the reaction tank is circulated to the raw water tank for further reaction, and the other part enters the enhanced reactor for photochemical reaction and synergistically degrades organic pollutants with the subsequently generated ozone, and then the effluent returns to the inlet side of the reaction tank for further reaction; the produced water overflows from the upper part of the outlet side of the reaction tank into the produced water tank, and enters the subsequent biochemical treatment process after adjusting the pH value of the produced water to 6-9. The invention uses ultraviolet-ozone synergistic oxidation to achieve the decomposition of organic matter in wastewater, but does not involve the recycling of acetone in wastewater. When this method is used to simultaneously treat chlorobenzene and acetone contained in wastewater, a large amount of oxidant and catalyst is added, resulting in high operating costs.

[0007] Patent CN112174414A discloses a comprehensive treatment device and method for acetone wastewater and organic halogenated wastewater. The device includes a pretreatment device before biochemical treatment, and the pretreatment device before biochemical treatment includes a resin adsorption system for treating wastewater containing acetone substances and an alkaline hydrolysis device for treating wastewater containing organic halides. In the pretreatment stage, the method converts organic bromine into sodium bromide for desalination and removal by alkaline hydrolysis on the one hand, and controls the concentration of ketone biological toxic substances by resin adsorption on the other hand. The pretreatment effluent enters the biochemical treatment after adjustment, and the biochemical effluent can meet the requirements of the park. The biochemical effluent can meet the reuse requirements after coagulation, sand filtration, and ozone catalytic oxidation. The invention uses resin adsorption and alkaline hydrolysis devices to treat acetone wastewater and organic halogenated wastewater, but is not suitable for treating volatile and highly toxic wastewater containing chlorobenzenes, and does not achieve the recycling of acetone.

[0008] In summary, the following technical problems exist in the process of using existing photocatalytic oxidation technology to treat wastewater containing chlorobenzene and acetone: 1. When hydrogen peroxide is used as the oxidant, the dosage of the oxidant and catalyst is large, the oxidation reaction time is long, and the operating cost is high.

[0009] 2. When ozone is used as an oxidant, the solubility of ozone gas in the water phase is low, the oxidation energy is low, the degradation of organic matter is not complete, and the ability to treat wastewater containing chlorobenzene and acetone is insufficient.

[0010] 3. Acetone in wastewater is not recycled.

[0011] If chlorobenzene and acetone in wastewater can be separated and then the product after photolysis of chlorobenzene can be treated by ozone ultraviolet light catalytic oxidation reaction, the oxidation efficiency can be effectively improved. At the same time, the separated acetone can be recycled and utilized, and the biodegradability of wastewater can be improved, which has strong economic benefits. Therefore, it is necessary to develop a method and device for treating wastewater containing chlorobenzene and acetone that can realize the reuse of oxidants, the recycling of acetone, and low operating costs. Summary of the invention

[0012] The invention provides a method and device for treating wastewater containing chlorobenzene and acetone, which solve the problems that when the existing ozone photocatalytic oxidation process treats chlorobenzene and acetone wastewater, the oxidation energy is low and the acetone is not effectively recycled, and provides a method and device for treating wastewater containing chlorobenzene and acetone, which can reuse an oxidant, recycle acetone and have low operating costs.

[0013] The technical solution of the present invention is: In a first aspect, a photocatalytic oxidation method for treating wastewater containing chlorobenzene and acetone is disclosed, comprising the following steps: 1) Homogenization treatment: homogenization treatment of wastewater containing chlorobenzene and acetone; 2) Primary oxidation: The wastewater after homogenization treatment is subjected to primary oxidation under the action of an oxidant, and ultraviolet cyclic oxidation is carried out at the same time. The acetone in the wastewater rises with the oxidant, so that chlorobenzene and acetone in the wastewater are separated, and the organic matter is initially oxidized and decomposed into intermediate products; 3) Acetone recovery and oxidant recycling: Acetone in wastewater is condensed and recovered, and the oxidant enters the secondary oxidation recycling; 4) Secondary oxidation: The effluent from the primary oxidation undergoes secondary oxidation under the action of an oxidant and ultraviolet cyclic oxidation at the same time; 5) Drainage reuse: The effluent after secondary oxidation is mixed with acetone condensate and then enters the sewage treatment plant for further utilization.

[0014] Preferably, the hydraulic retention time of the homogenization treatment in step 1) is 1-3 hours.

[0015] Preferably, in step 2), the hydraulic retention time of the primary oxidation is 0.5-1.5h, calculated based on the influent; the oxidant is ozone gas, and the concentration of ozone gas in the sewage is 20-100mg / L; and the primary oxidation reaction temperature is 55-65°C.

[0016] Preferably, in step 4), the secondary oxidation is calculated based on the influent, the hydraulic retention time is preferably 1-3h, the oxidant is ozone gas, and the ozone gas concentration in the sewage is 50-100 mg / L; the secondary oxidation reaction temperature is 45-55°C.

[0017] In a second aspect, a device used in the photocatalytic oxidation method for treating wastewater containing chlorobenzene and acetone is disclosed, comprising a homogenizing tank, a primary photocatalytic oxidation tank, a secondary photocatalytic oxidation tank and a monitoring pool connected in sequence by pipelines, the homogenizing tank is provided with a wastewater inlet pipeline, the primary photocatalytic oxidation tank is provided with an ozone inlet pipeline, an ultraviolet circulation pipeline 1 and a gas exhaust pipeline, an ultraviolet light reactor 1 is provided on the ultraviolet circulation pipeline 1, the gas exhaust pipeline is connected with a condensing tank, the condensing tank is provided with an ozone circulation pipeline and an acetone recovery pipeline, the ozone circulation pipeline is connected to the secondary photocatalytic oxidation tank, and the acetone recovery pipeline is connected to the monitoring pool; the secondary photocatalytic oxidation tank is provided with an ultraviolet circulation pipeline 2 and a fresh ozone inlet pipeline, an ultraviolet light reactor 2 is provided on the ultraviolet circulation pipeline 2, and the monitoring pool is provided with a treated sewage exhaust pipeline.

[0018] Preferably, the effective volume of the wastewater reaction area of ​​the UV reactor 1 is calculated based on the hydraulic retention time of the influent water of 10-50S.

[0019] Preferably, the effective volume of the wastewater reaction area of ​​the second ultraviolet light reactor is calculated based on the hydraulic retention time of the influent water of 10-40S.

[0020] Preferably, the hydraulic retention time of the condensation tank is 1.0-2.0h, calculated based on the water inlet.

[0021] Preferably, the hydraulic retention time of the monitoring pool is 1-4h.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) Based on the existing photocatalytic oxidation process, the present invention adds ozone stripping in the first-stage photocatalytic oxidation tank. By controlling the reaction temperature, at the boiling point of acetone, acetone in the wastewater rises to the condensation tank along with a part of the ozone gas for condensation recovery; the other part of the ozone gas is irradiated with ultraviolet light to generate excited hydroxyl radicals, which further oxidize and decompose the chlorobenzene photolysis products, thereby realizing the separation of chlorobenzene and acetone in the wastewater. The ozone gas has both stripping and oxidation functions.

[0023] (2) The ozone gas carrying the acetone gas is condensed in the condenser, and the non-condensable ozone in the upper part of the condenser is discharged to the secondary photocatalytic oxidation tank for use as an oxidant, thereby realizing the reuse of the oxidant.

[0024] (3) The liquid acetone solution at the bottom of the condensation tank is discharged to the monitoring pool to improve the biodegradability of the effluent after oxidation and realize the recovery and utilization of acetone.

[0025] (4) The effluent from the primary photocatalytic oxidation tank enters the secondary photocatalytic oxidation tank, where ozone is added as an oxidant. The oxidant comes from the reused ozone gas from the upper part of the condensation tank and fresh ozone gas as a supplement, so that the organic matter in the wastewater is oxidized and decomposed again. The effluent from the secondary photocatalytic oxidation tank and the acetone condensate enter the monitoring pool. The COD of the effluent from the monitoring pool is 200-600 mg / L, and the biodegradability is greater than 0.4, which not only improves the efficiency of photocatalytic oxidation, but also can be used as a high-quality carbon source in subsequent biochemical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the device of the present invention.

[0027] In the figure, 1. homogenization tank; 101. wastewater inlet pipeline; 2. primary photocatalytic oxidation tank; 201. ozone inlet pipeline; 202. UV circulation pipeline one; 2021. UV reactor one; 203. gas exhaust pipeline; 3. secondary photocatalytic oxidation tank; 301. UV circulation pipeline two; 3011. UV reactor two; 302. fresh ozone inlet pipeline; 4. monitoring tank; 401. treated sewage exhaust pipeline; 5. condensation tank; 501. ozone circulation pipeline; 502. acetone recovery pipeline. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] The analysis and testing methods and standards are shown in Table 1: Table 1 Analysis and testing methods and standards Analyze Project Analytical methods standard chlorobenzene Headspace / Gas Chromatography-Mass Spectrometry HJ 810-2016 acetone Headspace / Gas Chromatography-Mass Spectrometry HJ 810-2016 COD Verification procedures for online automatic monitoring instruments JJG 1012-2019 BOD Dilution inoculation method HJ 505-2009 Note: B / C is the ratio of BOD to COD.

[0030] A photocatalytic oxidation method for treating wastewater containing chlorobenzene and acetone comprises the following steps: 1) Homogenization treatment: The wastewater containing chlorobenzene and acetone is homogenized, and the hydraulic retention time is 1-3h; 2) Primary oxidation: The wastewater after homogenization treatment is subjected to primary oxidation under the action of an oxidant, and ultraviolet cyclic oxidation is carried out at the same time. The acetone in the wastewater rises with the oxidant, so that chlorobenzene and acetone in the wastewater are separated, and the organic matter is initially oxidized and decomposed into intermediate products; the primary oxidation is calculated based on the influent, and the hydraulic retention time is 0.5-1.5h; the oxidant is ozone gas, and the ozone gas concentration in the wastewater is 20-100mg / L; the primary oxidation reaction temperature is 55-65℃; 3) Acetone recovery and oxidant recycling: Acetone in wastewater is condensed and recovered, and the oxidant enters the secondary oxidation recycling; 4) Secondary oxidation: The effluent of the primary oxidation is subjected to secondary oxidation under the action of an oxidant, and ultraviolet circulation oxidation is performed simultaneously; the secondary oxidation is calculated based on the influent, the hydraulic retention time is preferably 1-3h, the oxidant is ozone gas, and the ozone gas concentration in the sewage is 50-100mg / L; the secondary oxidation reaction temperature is 45-55°C; 5) Drainage reuse: The effluent after secondary oxidation is mixed with acetone condensate and then enters the sewage treatment plant for further utilization.

[0031] The device used in the photocatalytic oxidation method for treating wastewater containing chlorobenzene and acetone comprises a homogenizing tank 1, a primary photocatalytic oxidation tank 2, a secondary photocatalytic oxidation tank 3 and a monitoring pool 4 which are sequentially connected by pipelines. The homogenizing tank 1 is provided with a wastewater inlet pipeline 101, the primary photocatalytic oxidation tank 2 is provided with an ozone inlet pipeline 201, an ultraviolet circulation pipeline 202 and a gas exhaust pipeline 203, an ultraviolet circulation pipeline 202 is provided with an ultraviolet reactor 2021, and a gas exhaust pipeline 203 is provided on the ultraviolet circulation pipeline 202. The pipeline 203 is connected to the condensation tank 5, and the condensation tank 5 is provided with an ozone circulation pipeline 501 and an acetone recovery pipeline 502. The ozone circulation pipeline 501 is connected to the secondary photocatalytic oxidation tank 3, and the acetone recovery pipeline 502 is connected to the monitoring tank 4; the secondary photocatalytic oxidation tank 3 is provided with an ultraviolet circulation pipeline 2 301 and a fresh ozone inlet pipeline 302, and an ultraviolet light reactor 2 3011 is provided on the ultraviolet circulation pipeline 2 301, and the monitoring tank 4 is provided with a treated sewage discharge pipeline 401.

[0032] The specific working process is: The wastewater first enters the homogenization tank 1 for buffering and homogenization, and then enters the primary photocatalytic oxidation tank 2 from the bottom. Ozone oxidant is added to the primary photocatalytic oxidation tank 2, and the ultraviolet light reactor performs oxidation cycle treatment. Chlorobenzene undergoes oxidation reaction here and is quickly degraded into non-volatile intermediate products. The reaction temperature of the primary photocatalytic oxidation tank 2 is set to the boiling point of acetone. Acetone in the wastewater rises to the condensation tank 5 along with ozone gas. The acetone gas condenses into liquid in the condensation tank 5. The non-condensable ozone gas in the upper part of the condensation tank 5 enters the secondary photocatalytic oxidation tank 3 as an oxidant for repeated use, and the lower acetone condensate is discharged to the monitoring pool 4 for recycling. The effluent of the primary photocatalytic oxidation tank 2 enters the secondary photocatalytic oxidation tank 3 from the bottom, and the oxidant ozone is added here. The ultraviolet light reactor performs oxidation cycle treatment, and the organic matter in the wastewater is oxidized and decomposed. The effluent of the secondary photocatalytic oxidation tank 3 and the acetone condensate enter the monitoring pool 4, and after mixing, they are discharged to the sewage treatment plant of the chemical park as a high-quality carbon source.

[0033] The above method and device are used in the following embodiments, and the specific parameters are defined as follows: Example 1 The wastewater containing chlorobenzene and acetone is treated by the wastewater treatment device containing chlorobenzene and acetone of the present application, as follows: A special rubber factory produces wastewater with chlorobenzene content of 379.4 mg / L, acetone content of 181.5 mg / L, COD of 700 mg / L, and B / C of 0.20. The operating parameters are as follows.

[0034] Homogenization tank 1: hydraulic retention time 3.0h.

[0035] Primary photocatalytic oxidation tank 2: hydraulic retention time is 1.5h, reaction temperature is 65℃, oxidant is ozone gas, and ozone gas concentration in sewage is 100mg / L.

[0036] UV reactor 1 2021: medium pressure UV lamp, UV wavelength 200-400nm, power 500W / m 3 The hydraulic retention time in the sewage area of ​​the reaction tube is 50S.

[0037] Condensation tank 5: hydraulic retention time 2.0h.

[0038] Secondary photocatalytic oxidation tank 3: hydraulic retention time 1.5h, reaction temperature 55℃, oxidant is ozone gas, ozone gas concentration in sewage is 100mg / L. Among them, the oxidant loss of the recycled primary photocatalytic oxidation tank is 30%, and fresh ozone is supplemented by 30mg / L.

[0039] UV reactor II 3011: medium pressure UV lamp, UV wavelength 200-400nm, power 500W / m 3The hydraulic retention time in the sewage area of ​​the reaction tube is 40S.

[0040] Monitoring pool 4: hydraulic retention time 4.0h.

[0041] Operation results: The chlorobenzene content in the effluent of monitoring pool 4 is <0.2mg / L, which is lower than 0.2mg / L in actual production and cannot be detected. The acetone content is 154.2mg / L, COD is 399.4mg / L. The chlorobenzene and COD contents meet the influent requirements of the sewage treatment plant in the chemical park; B / C is 0.41, and the biodegradability is significantly improved.

[0042] Comparative Example 1 A chemical plant uses hydrogen peroxide as an oxidant and ferric chloride solution as a catalyst to photocatalyze the wastewater in Example 1. The specific method is as follows: (1) Homogenization: The wastewater enters the homogenization tank, and a water outlet is set at the bottom of the homogenization tank. The hydraulic retention time is 3.0h, and the mixed wastewater is homogenized; (2) Photocatalytic oxidation: The effluent from the lower part of the homogenization tank enters the oxidation tank, and dilute hydrochloric acid solution is added to the oxidation tank to adjust the pH to 2.3. Then, ferric chloride solution and hydrogen peroxide solution are added. The preferred dosage of hydrogen peroxide solution (calculated as pure hydrogen peroxide) and the ratio of influent COD are 3:1, the hydraulic retention time is 3.0h, the reaction temperature is 55℃, and the total iron concentration in the oxidation tank is 100mg / L; the effluent from the lower part of the oxidation tank enters the ultraviolet reactor for ultraviolet irradiation, and then returns to the photocatalytic oxidation tank for circulation to deeply oxidize and decompose chlorobenzene and acetone; the power of the ultraviolet reactor is 1000W / m 3 The hydraulic retention time in the sewage area of ​​the reaction tube is 50S.

[0043] (3) Sedimentation: Sodium hydroxide solution is added to the effluent from the oxidation pond to adjust the pH value to 8.5, and then the effluent enters the sedimentation tank. The catalyst produces a flocculation effect to precipitate the suspended organic matter here; the hydraulic retention time is 1.5h; (4) Drainage: The effluent from the sedimentation tank enters the monitoring tank with a hydraulic retention time of 3.0 h and a pH value of 9. The effluent from the monitoring tank meets the discharge standards.

[0044] Operation results: The chlorobenzene content in the effluent from the monitoring pool is <0.2mg / L, the acetone content is 12.3mg / L, the COD is 25.0mg / L, and the B / C is 0.15. The chlorobenzene and COD contents both meet the requirements for direct discharge of wastewater from the enterprise.

[0045] The comparison of process operating parameters in Example 1 and Comparative Example 1 is shown in Table 2: Table 2 Treatment process <![CDATA[H2O2 addition amount mg / L]]> <![CDATA[O3 addition amount mg / L]]> Catalyst addition amount is based on total iron mg / L Oxidation reaction time h Outlet CODmg / L B / C Comparative Example 1 150 —— 100 3 25.0 0.15 Example 1 —— 130 —— 3 399.4 0.41 Compared with Example 1, when the comparative example 1 adopts the existing photocatalytic oxidation process and the oxidant is H2O2 for treatment, the chlorobenzene and acetone in the wastewater are not treated separately, the acetone is deeply degraded, the dosage of the oxidant and the catalyst is large, the effluent meets the direct discharge standard, and the operating cost is high; the present invention does not require the addition of a catalyst, and realizes the separation and recycling of acetone, the oxidized effluent has good biodegradability, and the practicality and economy are better than the comparative process.

[0046] Comparative Example 2 The wastewater in Example 1 is treated according to the existing ozone oxidation process, and the specific method is as follows: (1) Homogenization: The wastewater enters the homogenization tank, and a water outlet is set at the bottom of the homogenization tank. The hydraulic retention time is 3.0h, and the mixed wastewater is homogenized; (2) Ozone oxidation: The water from the lower part of the homogenization tank enters the oxidation tank, and the ozone gas concentration introduced is 150 mg / L. The hydraulic retention time is preferably 4 hours.

[0047] (3) Drainage: The effluent from the oxidation pond enters the monitoring pond with a hydraulic retention time of 4.0 h. The effluent from the monitoring pond is discharged to the sewage treatment plant in the chemical park.

[0048] Operation results: The chlorobenzene content in the effluent of the monitoring pool is 296.1 mg / L, the acetone content is 82.7 mg / L, the COD is 484.6 mg / L, and the B / C is 0.22, which means that the biodegradability is low. The chlorobenzene content cannot meet the influent requirements of the sewage treatment plant in the chemical park.

[0049] The comparison of the two process operating parameters is shown in Table 3: Table 3 Comparison of process technology between Example 1 and Comparative Example 2 Treatment process <![CDATA[O3 dosage mg / L]]> Reaction time h Outlet CODmg / L B / C Comparative Example 2 150 4 484.6 0.22 Example 1 130 3 399.4 0.41 When the ozone oxidation process is used for treatment in Comparative Example 2, the solubility of ozone gas in the aqueous phase is low, the oxidation energy is low, the degradation effect of organic matter is poor, the ability to treat wastewater containing chlorobenzene and acetone is insufficient, the COD of the effluent after oxidation is high, and the biodegradability is poor; the oxidant dosage of the technology of the present invention is small, the oxidation time is shortened, the separated acetone solution is recycled, the oxidized effluent has good biodegradability, and the oxidation efficiency and economy are better than the comparative process.

[0050] Example 2 A special rubber factory produces wastewater with chlorobenzene content of 144.5 mg / L, acetone content of 97.4 mg / L, COD of 260.3 mg / L, and B / C of 0.22. The operating parameters are as follows.

[0051] Homogenization tank 1: hydraulic retention time 1.0h.

[0052] Primary photocatalytic oxidation tank 2: hydraulic retention time is 0.5h, reaction temperature is 55℃, oxidant is ozone gas, and ozone gas concentration in sewage is 20mg / L.

[0053] UV reactor 1 2021: UV wavelength 200-400nm, power 500W / m 3 The hydraulic retention time in the sewage area of ​​the reaction tube is 10S.

[0054] Condensation tank 5: hydraulic retention time 1.0h.

[0055] Secondary photocatalytic oxidation tank 3: hydraulic retention time 1.0h, reaction temperature 45℃, oxidant is ozone gas, ozone gas concentration in sewage is 50mg / L, among which, the oxidant loss of the recycled primary photocatalytic oxidation tank is 50%, and fresh ozone is supplemented by 40mg / L.

[0056] UV reactor 2 3011: UV wavelength 200-400nm, power 500W / m 3 The hydraulic retention time in the sewage area of ​​the reaction tube is 10S.

[0057] Monitoring pool 4: hydraulic retention time 1.0h.

[0058] Operation results: The chlorobenzene content in the effluent of monitoring pool 4 is <0.2mg / L, the acetone content is 75.6mg / L, and the COD2 is 15.9mg / L. The chlorobenzene and COD contents meet the influent requirements of the chemical park sewage field; the B / C is 0.45, and the biodegradability is significantly improved.

[0059] Example 3 A special rubber factory produces wastewater with chlorobenzene content of 310.8 mg / L, acetone content of 145.3 mg / L, COD of 480.7 mg / L, and B / C of 0.21. The operating parameters are as follows.

[0060] Homogenization tank 1: hydraulic retention time 2.0h.

[0061] Primary photocatalytic oxidation tank 2: hydraulic retention time 1.0h, reaction temperature 60°C, oxidant is ozone gas, and ozone gas concentration in sewage is 80mg / L.

[0062] UV reactor 1 2021: UV wavelength 200-400nm, power 500W / m 3 The hydraulic retention time in the sewage area of ​​the reaction tube is 40S.

[0063] Condensation tank 5: hydraulic retention time 1.5h.

[0064] Secondary photocatalytic oxidation tank 3: hydraulic retention time 3.0h, reaction temperature 50℃, oxidant is ozone gas, ozone gas concentration in sewage is 80mg / L, among which, the oxidant loss of the recycled primary photocatalytic oxidation tank is 40%, and fresh ozone is supplemented by 32mg / L.

[0065] UV reactor 2 3011: UV wavelength 200-400nm, power 500W / m 3 The hydraulic retention time in the sewage area of ​​the reaction tube is 30S.

[0066] Monitoring pool 4: hydraulic retention time 3.0h.

[0067] Operation results: The chlorobenzene content in the effluent of monitoring pool 4 is <0.2mg / L, the acetone content is 85.9mg / L, and the COD content is 341.1mg / L. The chlorobenzene and COD content both meet the influent requirements of the chemical park sewage field; the B / C is 0.43, and the biodegradability is significantly improved.

[0068] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for treating wastewater containing chlorobenzene and acetone, characterized in that: The following steps are involved: 1) Homogenization treatment: homogenization treatment of wastewater containing chlorobenzene and acetone; 2) Primary oxidation: The wastewater after homogenization treatment is subjected to primary oxidation under the action of an oxidant, and ultraviolet cyclic oxidation is carried out at the same time. The acetone in the wastewater rises with the oxidant, so that chlorobenzene and acetone in the wastewater are separated, and the organic matter is initially oxidized and decomposed into intermediate products; 3) Acetone recovery and oxidant recycling: Acetone in wastewater is condensed and recovered, and the oxidant enters the secondary oxidation recycling; 4) Secondary oxidation: The effluent from the primary oxidation undergoes secondary oxidation under the action of an oxidant and ultraviolet cyclic oxidation at the same time; 5) Drainage reuse: The effluent after secondary oxidation is mixed with acetone condensate and then enters the sewage treatment plant for further utilization.

2. The method for treating wastewater containing chlorobenzene and acetone according to claim 1, characterized in that: The hydraulic retention time of the homogenization treatment in step 1) is 1-3h.

3. The method for treating wastewater containing chlorobenzene and acetone according to claim 1, characterized in that: In step 2), the primary oxidation is calculated based on the influent, and the hydraulic retention time is 0.5-1.5h; the oxidant is ozone gas, and the ozone gas concentration in the sewage is 20-100mg / L; the primary oxidation reaction temperature is 55-65°C.

4. The method for treating wastewater containing chlorobenzene and acetone according to claim 1, characterized in that: In step 4), the secondary oxidation is calculated based on the influent, the hydraulic retention time is 1-3h, the oxidant is ozone gas, and the ozone gas concentration in the sewage is 50-100mg / L; the secondary oxidation reaction temperature is 45-55°C.

5. The device used in the method for treating wastewater containing chlorobenzene and acetone according to any one of claims 1 to 4, characterized in that: The invention comprises a homogenizing tank (1), a primary photocatalytic oxidation tank (2), a secondary photocatalytic oxidation tank (3) and a monitoring pool (4) which are connected in sequence through pipelines. The homogenizing tank (1) is provided with a wastewater inlet pipeline (101). The primary photocatalytic oxidation tank (2) is provided with an ozone inlet pipeline (201), a first ultraviolet circulation pipeline (202) and a gas exhaust pipeline (203). The first ultraviolet circulation pipeline (202) is provided with a first ultraviolet reactor (221). The gas exhaust pipeline (203) is connected with a condensing tank (5). The condensation tank (5) is provided with an ozone circulation pipeline (501) and an acetone recovery pipeline (502); the ozone circulation pipeline (501) is connected to the secondary photocatalytic oxidation tank (3); and the acetone recovery pipeline (502) is connected to the monitoring pool (4); the secondary photocatalytic oxidation tank (3) is provided with a second ultraviolet circulation pipeline (301) and a fresh ozone inlet pipeline (302); a second ultraviolet reactor (3011) is provided on the second ultraviolet circulation pipeline (301); and the monitoring pool (4) is provided with a treated sewage discharge pipeline (401).

6. The device used in the method for treating wastewater containing chlorobenzene and acetone as claimed in claim 5, characterized in that: The effective volume of the wastewater reaction area of ​​UV reactor 1 (2021) is calculated based on the inlet hydraulic retention time of 10-50S.

7. The device used in the method for treating wastewater containing chlorobenzene and acetone as claimed in claim 5, characterized in that: The effective volume of the wastewater reaction area of ​​UV reactor 2 (3011) is calculated based on the hydraulic retention time of the influent water of 10-40S.

8. The device used in the method for treating wastewater containing chlorobenzene and acetone as claimed in claim 5, characterized in that: The hydraulic retention time of the condensation tank (5) is 1.0-2.0h, calculated based on the water inlet.

9. The device used in the method for treating wastewater containing chlorobenzene and acetone as claimed in claim 5, characterized in that: The hydraulic retention time of the monitoring pool (4) is 1-4 hours.

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