Method and device for treating supersaturated wastewater containing chlorobenzene organic matters

Abstract

The invention discloses a method and a device for treating supersaturated wastewater containing chlorobenzene organic matters, and belongs to the technical field of high-concentration organic wastewater treatment. According to the technical scheme, the method for treating the supersaturated wastewater containing the chlorobenzene organic matters comprises the following steps: 1) separating and dissolving undissolved chlorobenzene; 2) oxidizing chlorobenzene and regenerating filler; 3) thoroughly oxidizing chlorobenzene and intermediate products thereof; (4) flocculating settling; the device comprises a first-stage reaction tower, a second-stage reaction kettle and a flocculation sedimentation tank which are sequentially connected through pipelines, the first-stage reaction tower is provided with a wastewater inlet pipeline and a first-stage reaction tower water outlet pipeline, and the first-stage reaction tower water outlet pipeline is provided with an acid liquor feeding pipeline, an oxidizing agent I or catalyst feeding pipeline and a first-stage UV reactor; and a second-stage UV reactor is arranged on a pipeline between the first-stage reaction tower and the second-stage reaction kettle. The method is suitable for treatment processes of high-concentration / supersaturated chlorobenzene-containing organic matter wastewater and high-concentration / supersaturated chlorobenzene-containing organic matter wastewater.

Description

Technical Field

[0001] The invention belongs to the technical field of high-concentration organic wastewater treatment, and specifically relates to a method and device for treating supersaturated chlorobenzene-containing organic wastewater. Background Art

[0002] With the development of modern chemical industry, organic additives are used more and more widely. However, while producing high-quality products, the added organic additives are often discharged with wastewater. In the process of production equipment process design, stripping towers are generally designed to recover organic additives. However, since some additives have low solubility in water, the recovery process often leads to unstable operation of the recycling facilities, and supersaturated organic wastewater is discharged from the production equipment. If it is sent directly to a sewage field or treatment facility, the supersaturated precipitated organic matter will remain at the bottom or top of the structure, and will be released persistently, greatly increasing the difficulty of treatment. Therefore, this type of wastewater is often sent to accident tanks for temporary storage, and finally treated as hazardous waste at a high cost, which is contrary to the concept of green and high-quality development of enterprises.

[0003] Chlorobenzene is a typical organic auxiliary agent, which is colorless, transparent, and volatile. It can be used as an intermediate and solvent in organic synthesis and has a wide range of uses. Under normal circumstances, chlorobenzene has a low solubility in water. Once supersaturated wastewater is generated, chlorobenzene will settle to the bottom of the accident tank or the reactor or structure of the treatment facility, causing a lasting impact on the downstream sewage treatment facilities and leading to unstable operation. Chlorobenzene is biologically toxic. Chlorobenzene-containing wastewater, especially supersaturated chlorobenzene wastewater, cannot be treated by biological treatment. Advanced oxidation processes are generally used. When using advanced oxidation processes, chlorobenzene is prone to generate intermediates such as chlorophenol, hydroquinone, and benzoquinone under the action of advanced oxidation factors. These intermediates are still environmentally toxic substances and must be further carbonized in time to remove the toxicity. At present, in the treatment process of supersaturated chlorobenzene, these toxic intermediates are difficult to remove completely, resulting in the effluent still containing toxicity.

[0004] Chinese invention patent CN115536187A discloses a method and device for treating chlorobenzene-containing wastewater. The wastewater first enters a homogenization tank for buffering, and then is mixed with the outlet water of the oxidation tank and the chlorobenzene waste gas at the top of the homogenization tank, and then enters a UV generator for oxidation cycle treatment; the water from the upper part of the oxidation tank is adjusted to pH value and then enters a laminated filter, where the catalyst solid particles are intercepted, and the water from the filter is adjusted to pH value again to the monitoring pool and then discharged to the standard; the backwash water of the laminated filter contains catalyst, and enters a catalyst tank for catalyst recovery, and the recovered catalyst is injected into the oxidation tank through a reagent pump; the tail gas is discharged from the top of the oxidation tank in compliance with the standard. The waste gas is introduced into the wastewater treatment pipeline, and the wastewater and waste gas are treated with the same device, saving subsequent waste gas investment and land occupation; the alkali solution is added in batches, saving the amount of acid added for backwashing of the laminated filter; the catalyst is recovered, and the catalyst is recycled after one addition, which improves the oxidation efficiency and does not produce waste residue. This invention patent provides an efficient method for treating chlorobenzene wastewater. However, when treating chlorobenzene wastewater with a concentration of 400 mg / L or supersaturated chlorobenzene, it is difficult to control the effluent chlorobenzene to meet the standard because the chlorobenzene liquid phase is oxidized and dissolved during the oxidation process. The only way is to reduce the efficiency of the device and gradually degrade chlorobenzene and intermediate products in a cyclic treatment until the standard is met. The treatment time is long and the energy consumption is high. When the chlorobenzene liquid phase concentration is relatively high, the retention of the intermediate product causes the wastewater oxidation process to darken in color, resulting in a further decrease in the photooxidation efficiency.

[0005] Chinese invention patent CN106865825A discloses a method for treating wastewater containing benzene and chlorobenzene. First, the pH of the wastewater to be treated is adjusted, and then a flocculant is added, mixed, and then the precipitate is removed by filtering. Finally, the wastewater from which the precipitate has been removed is subjected to high-efficiency catalytic oxidation to remove benzene and chlorobenzene. When high-concentration chlorobenzene wastewater or supersaturated chlorobenzene wastewater is treated by high-efficiency catalytic oxidation, since the density of chlorobenzene is slightly greater than that of water, both the pre-precipitate and the precipitated water contain a chlorobenzene liquid phase, and the precipitate is difficult to be separated from the mud and water in an environmentally friendly manner. The high-efficiency catalytic oxidation process cannot completely render the wastewater inorganic and harmless due to the excessively high chlorobenzene concentration and chlorobenzene liquid beads, resulting in poor treatment effect, unstable operation control, and a situation where it is difficult to meet the standards, which is still harmful to the environment.

[0006] Chinese invention patent CN 105565416 A discloses a method for treating wastewater from a chlorobenzene plant, specifically involving a method for pre-treating wastewater using a metal-loaded activated carbon adsorption treatment device. The activated carbon is modified and used for adsorption treatment of wastewater under low temperature conditions, and then the adsorbent is purged with low-pressure steam and nitrogen under high temperature conditions for desorption, and benzene and chlorobenzene are recovered. The adsorbent after desorption can be reused. The content of benzene and chlorobenzene in the treated chlorobenzene wastewater is less than 100ppm, and the organic matter removal rate reaches more than 90%, which saves resources and reduces the cost of wastewater biochemical treatment. In the embodiment, the concentration of chlorobenzene treated is 200-300mg / L, and the chlorobenzene after treatment is less than 100mg / L. The toxicity of chlorobenzene cannot be completely eliminated and steam regeneration of activated carbon is required.

[0007] In summary, the current treatment process of chlorobenzene-containing wastewater, especially supersaturated chlorobenzene wastewater, has the following technical problems: 1. Due to the existence of chlorobenzene liquid phase, it is difficult to use the existing process to achieve harmless discharge standards, and the treatment cost is high when it is used for hazardous disposal.

[0008] 2. When wastewater is treated with advanced oxidation, once supersaturated chlorobenzene is precipitated, it will cause a persistent and slow release in the treatment facility, resulting in reduced treatment effect and difficulty in operation control.

[0009] 3. The intermediate product of chlorobenzene oxidation is dark in color and still has high environmental toxicity. High concentration of chlorobenzene wastewater leads to a significant decrease in the efficiency of ultraviolet oxidation, prolonged oxidation time, and increased operating costs. When the oxidation is not complete, it is still harmful to the environment.

[0010] 4. The precipitate from the pretreatment process contains chlorobenzene, which makes it difficult to separate the precipitate from mud and water in an environmentally friendly manner, causing serious pollution to the environment and posing health risks to the processing personnel.

[0011] 5. The use of modified activated carbon to adsorb chlorobenzene has the problem of incomplete removal of pollutants and high regeneration cost.

[0012] Therefore, it is necessary to develop a treatment method and device that is environmentally friendly and can efficiently and thoroughly remove organic matter from supersaturated chlorobenzene wastewater. Summary of the invention

[0013] The present invention provides a method and device for treating supersaturated chlorobenzene-containing organic wastewater, which solves the problems of high chlorobenzene concentration, high treatment difficulty, unstable operation of treatment facilities, etc. in the existing supersaturated chlorobenzene wastewater treatment process. A method and device for treating supersaturated chlorobenzene wastewater with an environmentally friendly treatment process and high efficiency and thorough removal of organic matter is provided. The present invention is applicable to high-concentration / supersaturated chlorobenzene-containing organic wastewater and high-concentration / supersaturated chlorobenzene-containing organic wastewater treatment processes, and is also applicable to other high-concentration organic wastewater and supersaturated other organic wastewater treatment processes.

[0014] The technical solution of the present invention is: In a first aspect, a method for treating supersaturated chlorobenzene-containing organic wastewater is disclosed, comprising the following steps: 1) Separation and dissolution of undissolved chlorobenzene: Supersaturated chlorobenzene-containing organic wastewater enters the primary reaction tower under the pressure of the pipeline or the lifting of a water pump, and mixes with the effluent of the primary reaction tower to form mixed wastewater. The mixed wastewater passes through the packing layer from bottom to top in the reaction tower, and undissolved chlorobenzene is intercepted by the packing; 2) Oxidation of chlorobenzene and regeneration of packing: Acid, oxidant 1 and catalyst are added to the mixed wastewater flowing out from the top of the primary reaction tower, and then the mixed wastewater is pumped into the primary UV reactor for oxidation and then enters the packing layer of the primary reaction tower for regeneration of the packing layer. The mixed wastewater 2 in the effluent of the primary reaction tower is refluxed to continue dissolving chlorobenzene, and the mixed wastewater 3 is pumped into the secondary UV reactor; 3) Complete oxidation of chlorobenzene and its intermediates: add oxidant 2 to the mixed waste liquid 3 lifted by the water pump, and then mix it with the circulating water from the secondary reactor lifted by the circulating water pump, enter the secondary UV reactor, return to the secondary reactor for cyclic degradation, and after cyclic degradation, form mixed waste liquid 4 that overflows out of the secondary reactor; 4) Flocculation and sedimentation: Add alkali solution and coagulant to the mixed waste liquid No. 4, and subject the mixed waste liquid No. 4 to flocculation and sedimentation treatment before it meets the discharge standards.

[0015] The water pump is an acid and alkali resistant water pump and is selected according to conventional design.

[0016] Preferably, the primary reaction tower and the secondary reaction kettle are made of one of polytetrafluoroethylene, polyethylene or enamel; based on the influent water, the hydraulic retention time of the primary reaction tower is 1.0-3.0h, and the hydraulic retention time of the secondary reaction kettle is 3.0-6.0h.

[0017] Preferably, the first oxidant is a hydrogen peroxide solution, the dosage of which is 1000-2000 mg / L as pure hydrogen peroxide, and the concentration of the effluent from the primary reaction tower is 500-1500 mg / L as pure hydrogen peroxide; the second oxidant is ozone, persulfate or a hydrogen peroxide solution, preferably a hydrogen peroxide solution, and the dosage of which is 50-500 mg / L as pure oxidant two.

[0018] Preferably, the catalyst is a ferric salt or a divalent iron salt, and the total iron concentration in the primary reaction tower is 50-100 mg / L; the acid solution is sulfuric acid or hydrochloric acid, and the alkali solution is sodium hydroxide or potassium hydroxide.

[0019] Preferably, the reaction temperature of the primary reaction tower is 60-65°C, and the reaction pH value of the primary reaction tower is 2.0-2.5; the reaction temperature of the secondary reaction kettle is 45-55°C, and the reaction pH value of the secondary reaction kettle is 2.5-3.0.

[0020] Preferably, the primary reaction tower is provided with a filler, and the filler is one of granular activated carbon, columnar activated carbon or activated carbon fiber. The empty tower hydraulic retention time of the filler layer is 0.5 to 2.0 h based on the influent water.

[0021] Preferably, the total effluent flow rate from the primary reaction tower is 2-5 times the inlet flow rate, the effluent flow rate to the secondary UV reactor is the same as the inlet flow rate, and the rest goes to the primary UV reactor; the effluent flow rate from the secondary reactor is 3-10 times the inlet flow rate.

[0022] Preferably, the UV lamp of the primary UV reactor is a lamp with a wavelength of 200-400nm, preferably a medium-pressure UV lamp, and preferably has an installed power of 2000-3000W / m 3 The UV lamp of the secondary UV reactor is a lamp with a wavelength of 200-400nm, preferably a medium-pressure UV lamp, preferably with an installed power of 500-2000W / m 3 .

[0023] Preferably, the pH value of the flocculation sedimentation tank is 7-9, the coagulant is polyacrylamide, the addition concentration is 1-10 mg / L, and the hydraulic retention time is 2-4 h.

[0024] In a second aspect, the supersaturated chlorobenzene-containing organic wastewater treatment device is disclosed, comprising a primary reaction tower, a secondary reaction kettle and a flocculation sedimentation tank connected in sequence by pipelines, a packing layer is arranged in the primary reaction tower, the primary reaction tower is provided with a wastewater inlet pipeline, a primary reaction tower outlet pipeline, the primary reaction tower outlet pipeline is provided with an acid feed pipeline, an oxidant one or a catalyst feed pipeline and a primary UV reactor; an alkali solution inlet pipeline one, an oxidant two inlet pipeline and a secondary UV reactor are arranged on the pipeline between the primary reaction tower and the secondary reaction kettle, an alkali solution inlet pipeline two is arranged on the pipeline between the secondary reaction kettle and the flocculation sedimentation tank, the secondary reaction kettle is also provided with a return water pipeline, and the flocculation sedimentation tank is provided with a treated wastewater outlet pipeline.

[0025] The specific working process is as follows: supersaturated chlorobenzene wastewater as influent first enters the primary reaction tower under pipeline pressure or water pump lifting action. A packing layer is arranged in the primary reaction tower. After the influent and the effluent of the primary reactor are mixed in the lower space of the packing layer, they flow through the packing layer from bottom to top. The undissolved chlorobenzene liquid phase in the influent is blocked by the packing in the lower area of ​​the packing, and the wastewater phase enters the packing layer. In the packing layer, the packing absorbs the dissolved chlorobenzene in the influent and the oxidant, oxidative free radicals and chlorobenzene intermediates in the effluent of the primary UV reactor, and carries out adsorption, oxidation and decomposition in the pores of the packing. Part of the effluent (mixed waste liquid II) of the primary reaction tower packing is lifted by a water pump and added with acid, oxidant I and catalyst, and then returns to the primary UV reactor for circulation. Part of the effluent (mixed waste liquid III) is lifted by a water pump and added with alkali and oxidant II, and then enters the secondary UV reactor. The relatively acidic environment in the primary reaction tower is controlled. The oxidant 1 and the catalyst undergo cooperative catalytic oxidation under the action of the primary UV reactor to produce high-concentration, highly oxidizing hydroxyl radicals. After adding acid, oxidant 1 and catalyst to the effluent of the primary reaction tower packing (mixed waste liquid 2), it returns to the circulation pipeline of the primary UV reactor. In particular, a certain oxidant concentration is maintained in the packing layer of the primary reaction tower to efficiently degrade organic matter such as chlorobenzene. The effluent from the packing layer does not contain undissolved chlorobenzene. After adding an appropriate amount of alkali solution to the effluent entering the secondary UV reactor to reduce the acidic environment, it is mixed with the effluent from the circulating pump of the secondary reactor. The residual catalyst in the oxidant 2 and the effluent mixed waste liquid 3 (mixed waste liquid 3 contains a catalyst, and the catalyst comes from the catalyst added to the mixed waste liquid 2) and the secondary UV reactor undergo cooperative catalytic oxidation, and high-concentration hydroxyl radicals are produced again. In the secondary reactor, organic matter such as chlorobenzene is cyclically oxidized to be relatively completely inorganic. After the effluent from the secondary reactor is adjusted to neutral by adding alkali solution, coagulant is added to the flocculation sedimentation tank to achieve mud-water separation, and the supernatant is discharged as effluent.

[0026] The present invention realizes the wastewater treatment process by jointly completing the synergistic effect of a primary reaction tower and a primary UV reactor, and the synergistic effect of a secondary reaction tower and a secondary UV reactor. The working principle is as follows: after undissolved chlorobenzene in the influent water is intercepted by the filler layer, the chlorobenzene in the influent water phase and the effluent water of the primary reactor is oxidized by hydroxyl radicals in the water, and the chlorobenzene is rapidly oxidized by the hydroxyl radicals to form chlorophenols, an intermediate product with good water solubility, so that the concentration of chlorobenzene is greatly reduced. However, the chlorophenols cause the chromaticity of the wastewater to increase. On the one hand, the filler of the invention participates in the adsorption oxidation process, so that chlorobenzene and its oxidation intermediates are adsorbed and oxidized. In the effluent water of the upper layer of the filler, the chromaticity generated by the chlorobenzene intermediates is greatly reduced, thereby improving the catalytic efficiency of ultraviolet light in the primary UV reactor and the secondary UV reactor; on the other hand, the filler intercepts the undissolved liquid phase of chlorobenzene. Due to the generation of chlorophenols, the chlorobenzene concentration decreases, and the chlorobenzene intercepted in the lower layer of the filler continues to dissolve. Due to the interception effect of the filler, according to the characteristic that the density of chlorobenzene is greater than that of water, a certain reaction temperature is controlled, and the chlorobenzene liquid beads are divided and broken by the filler, so that the dissolution process of chlorobenzene is accelerated, and the chlorobenzene liquid phase in the supersaturated chlorobenzene wastewater is ensured to be dissolved again. The effluent from the primary reaction tower no longer contains chlorobenzene liquid phase, but is a homogeneous wastewater. A part of the effluent from the primary reaction tower circulates into the primary UV reactor to continue to dissolve the chlorobenzene liquid phase in the inlet water, and the other part enters the secondary UV reactor. The remaining newly added oxidant 2, the residual oxidant 1 and the catalyst in the effluent continue to undergo deep catalytic oxidation. In the cyclic oxidation process of the secondary oxidation reactor, chlorobenzene and the intermediate products are completely converted into carbon dioxide and water. After the pH value of the effluent from the secondary reactor is adjusted, the added catalyst is converted into a flocculant in the flocculation sedimentation tank to produce an efficient precipitation effect, and insoluble substances are continuously removed, and the effluent reaches the direct discharge standard. The filler in the primary reaction tower is in a dynamic process of adsorption and oxidation regeneration of adsorbed free radicals. Under the reaction temperature conditions of the present invention, the filler does not need to be regenerated offline.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The problem of a significant decrease in the efficiency of ultraviolet catalytic oxidation due to the color of the chlorobenzene intermediate product during the treatment of high-concentration chlorobenzene wastewater was solved through filler adsorption oxidation.

[0028] (2) On the basis of the efficient oxidation of chlorobenzene by ultraviolet catalytic oxidation, the gradual dissolution of the chlorobenzene liquid phase was achieved by utilizing the area under the filler. The turbulent flow disturbance of the water flow under the filler and the blocking effect of the filler both promoted the continued dissolution of chlorobenzene.

[0029] (3) The UV reactor is used to increase the water temperature and control the reaction temperature, thereby ensuring that chlorobenzene is efficiently dissolved and that the dissolved chlorobenzene is no longer saturated and precipitated, thereby promoting the effect of ultraviolet catalytic oxidation.

[0030] (4) Under the pH value environment and temperature parameters of the primary reaction tower, the process of adsorption and oxidation of chlorobenzene by the filler is ensured to proceed smoothly. At the same time, the oxidative free radicals have an adsorption and regeneration effect on the filler, ensuring that the filler continues to function efficiently and does not need to be regenerated offline.

[0031] (5) The environmentally friendly treatment of the chlorobenzene liquid phase in the supersaturated chlorobenzene wastewater was achieved. Compared with the outsourcing of hazardous waste disposal, the operating cost is lower, it is harmless to the environment, and meets the requirements of the company's green development.

[0032] (6) The present invention solves the problem that the existing process for supersaturated chlorobenzene wastewater cannot be effectively treated under normal circumstances and can only be treated as hazardous waste. The treatment process of the present invention is more environmentally friendly.

[0033] (7) During the oxidation process, chlorobenzene is first oxidized into toxic intermediates such as chlorophenol, hydroquinone, and quinone. Due to the presence of chlorobenzene liquid phase, the supersaturated wastewater dissolves and reacts at the same time. As a result, chlorobenzene and the intermediate products cannot be completely harmlessly treated in the same reaction system, which reduces the oxidation efficiency and makes it difficult for the effluent to meet the standards. The present invention uses fillers in the primary reaction tower to solve the problem of separating chlorobenzene liquid phase and water, efficiently converting chlorobenzene into intermediate products and promoting the continued dissolution of chlorobenzene; in the secondary reactor, there is no chlorobenzene liquid phase, only homogeneous wastewater, and the chlorobenzene and intermediate products dissolved in the water can be efficiently oxidized, completely achieving the harmless discharge of wastewater that meets the standards.

[0034] (8) The filler of the present invention has the function of intercepting and separating the aqueous phase and the chlorobenzene liquid phase in the wastewater, and also has the function of adsorbing the dissolved organic matter, free radicals and oxidants in the water, creating the conditions for adsorption oxidation. Under the preferred process conditions, the organic matter, free radicals and oxidants adsorbed in the pores of the filler have a higher probability of collision oxidation. After the organic matter is oxidized, the pores of the filler are released, realizing the self-circulation of filler adsorption-regeneration-adsorption. The filler does not need to set up an offline regeneration process, which solves the problem of using activated carbon to adsorb chlorobenzene and then needing to use steam and nitrogen for offline regeneration in the prior art. In addition, the adsorption of organic matter by the filler also reduces the chromaticity of the wastewater, ensuring that the primary reaction tower cycle process efficiently treats chlorobenzene and improving the oxidation efficiency. The chromaticity of the wastewater going to the secondary reactor is also greatly reduced, creating conditions for the complete oxidation and harmless treatment of the secondary reactor.

[0035] (9) The synergistic effect of the primary reaction tower and the secondary reactor. The primary reaction tower controls the oxidation process by operating conditions to mainly convert chlorobenzene into intermediate products, while the secondary reactor controls the operating conditions to mainly completely oxidize organic matter such as chlorobenzene and chlorobenzene intermediates. This solves the problems of unstable operation, difficult control of the treatment process, and incomplete oxidation caused by the chlorobenzene liquid phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1It is a structural schematic diagram of the present invention.

[0037] In the figure, 1, primary reaction tower; 101, packing layer; 102, wastewater inlet pipeline; 103, primary reaction tower outlet pipeline; 104, acid feed pipeline; 105, oxidant 1 or catalyst feed pipeline; 2, secondary reactor; 3, flocculation sedimentation tank; 4, primary UV reactor; 5, alkali solution inlet pipeline 1; 6, oxidant 2 inlet pipeline; 7, secondary UV reactor; 8, alkali solution inlet pipeline 2; 9, return water pipeline; 10, treated wastewater outlet pipeline. DETAILED DESCRIPTION

[0038] The embodiments all adopt the method and device for recycling supersaturated chlorobenzene-containing wastewater of the present invention, and further illustrate the beneficial effects of the present invention.

[0039] The invention provides a supersaturated chlorobenzene-containing organic wastewater treatment device, comprising a primary reaction tower 1, a secondary reaction kettle 2 and a flocculation sedimentation tank 3 which are sequentially connected through pipelines, wherein a packing layer 101 is arranged in the primary reaction tower 1, the primary reaction tower 1 is provided with a wastewater inlet pipeline 102 and a primary reaction tower outlet pipeline 103, the primary reaction tower outlet pipeline 103 is provided with an acid feed pipeline 104, an oxidant one or catalyst feed pipeline 105 and a primary UV reactor 4; an alkali solution inlet pipeline one 5, an oxidant two inlet pipeline 6 and a secondary UV reactor 7 are arranged on the pipeline between the primary reaction tower 1 and the secondary reaction kettle 2, an alkali solution inlet pipeline two 8 is arranged on the pipeline between the secondary reaction kettle 2 and the flocculation sedimentation tank 3, the secondary reaction kettle 2 is further provided with a return water pipeline 9, and the flocculation sedimentation tank 3 is provided with a treated wastewater outlet pipeline 10.

[0040] It should be noted that the water flow driving force of the present invention is provided by a conventionally arranged water pump. On the water inlet pipeline, if the pipeline pressure is insufficient, a water pump needs to be arranged to lift the water into the primary reaction tower 1; a water pump is arranged on the pipeline between the primary reaction tower 1 and the acid liquid feed pipeline 104; a water pump is arranged on the pipeline between the primary reaction tower 1 and the alkali liquid inlet pipeline 5; and a circulating water pump is arranged on the return water pipeline 9 at the circulation outlet of the secondary reactor 2 before mixing with the water discharged from the primary reaction tower 1 to which the alkali liquid is added.

[0041] The method for treating supersaturated chlorobenzene-containing organic wastewater comprises the following steps: 1) Separation and dissolution of undissolved chlorobenzene: The supersaturated chlorobenzene-containing organic wastewater enters the primary reaction tower 1 along the wastewater inlet pipe 102, and mixes with the effluent from the primary reaction tower effluent pipe 103 to form mixed wastewater. The mixed wastewater passes through the packing layer 101 from bottom to top in the reaction tower, and the undissolved chlorobenzene is intercepted by the packing; at the same time, due to the low chlorobenzene concentration in the effluent of the primary UV reactor 4, chlorobenzene can continue to be efficiently dissolved and intercepted under the temperature conditions of the lower layer of the packing. It should be noted that when the device is initially operated, the effluent in the primary reaction tower effluent pipe 103 is the start-up water or reaction water reserved in the primary reaction tower 1.

[0042] 2) Oxidation of chlorobenzene and regeneration of packing: Acid, oxidant 1 and catalyst are added to the mixed wastewater flowing out from the top of the primary reaction tower 1. At a certain temperature, the chlorobenzene in the wastewater is in an oxidative excited state after photolysis after being irradiated by high-intensity ultraviolet light. At the same time, oxidant 1 is catalytically decomposed by high-intensity ultraviolet light to produce hydroxyl free radicals and native oxygen, which efficiently oxidizes chlorobenzene and reduces the concentration of chlorobenzene in the wastewater. Then, after being oxidized in the primary UV reactor, it enters the packing layer of the primary reaction tower 1 for regeneration of the packing layer. After the effluent of the primary UV reactor leaves the catalytic action of the ultraviolet light, the oxidant 1 in the effluent reacts with the strong oxidizing free radicals. The organic matter in the wastewater is continuously degraded efficiently and enters the packing layer. The packing simultaneously adsorbs chlorobenzene and the colored chlorobenzene oxidation intermediates, as well as hydroxyl radicals and native oxygen, increasing the contact probability between the organic matter and the oxidizing radicals and improving the oxidation effect. After being adsorbed, the organic matter is decomposed by the radicals, thus realizing the dynamic regeneration of the packing. The mixed waste liquid in the effluent of the primary reaction tower is refluxed for further dissolving chlorobenzene, and the mixed waste liquid is sent to the secondary UV reactor. The temperature control of this process is to realize the efficient dissolution of chlorobenzene in step 1, and to realize the dynamic regeneration of the packing, while taking into account the oxidation efficiency.

[0043] 3) Complete oxidation of chlorobenzene and its intermediates: The effluent mixed waste liquid 3 from the primary reaction tower 1 no longer contains chlorobenzene liquid phase. The remaining oxidant 1 and catalyst in the water are adjusted to acidity and temperature conditions more suitable for advanced oxidation, and then oxidant 2 is added to the mixed waste liquid 3. The mixed waste liquid 3 is recycled and degraded in the secondary UV reactor 7 and the secondary reactor 2 to achieve efficient and complete oxidation of chlorobenzene and other organic matter in the wastewater. After cyclic degradation, mixed waste liquid 4 is formed and flows out of the secondary reactor 2; 4) Flocculation and sedimentation: add alkali solution and coagulant to the mixed waste liquid No. 4. The catalyst has both catalytic and flocculation functions. The catalyst is iron salt, which acts as a catalyst under acidic conditions, ultraviolet light and hydrogen peroxide. When the pH value is adjusted to 7-9, the iron ion has a flocculation effect. The coagulant is added to assist in the flocculation and sedimentation treatment of the mixed waste liquid No. 4 before it meets the discharge standards.

[0044] The materials of the primary reaction tower 1 and the secondary reaction kettle 2 are both polytetrafluoroethylene, polyethylene, or enamel. The material used in the embodiments and comparative examples is carbon steel lined with anti-corrosion material enamel; based on the water inlet, the hydraulic retention time of the primary reaction tower 1 is 1-3h, and the hydraulic retention time of the secondary reaction kettle 2 is 3-6h.

[0045] The first oxidant is a hydrogen peroxide solution, and the dosage is 1000-2000 mg / L based on pure hydrogen peroxide. The concentration of the effluent from the primary reaction tower 1 is 500-1500 mg / L based on pure hydrogen peroxide. The second oxidant is ozone, persulfate or a hydrogen peroxide solution, preferably a hydrogen peroxide solution, and the dosage is 50-500 mg / L based on pure oxidant two.

[0046] The catalyst is a ferric salt or a divalent iron salt, and the total iron concentration of the primary reaction tower 1 is 50-100 mg / L; the acid solution is sulfuric acid or hydrochloric acid, and the alkali solution is sodium hydroxide or potassium hydroxide.

[0047] The reaction temperature of the primary reaction tower 1 is 60-65°C, the control method is ultraviolet power adjustment, and the reaction pH value of the primary reaction tower 1 is 2.0-2.5; the reaction temperature of the secondary reactor 2 is 45-55°C, the temperature control method is circulating water, and the reaction pH value of the secondary reactor 2 is 2.5-3.0.

[0048] The primary reaction tower 1 is provided with a filler, which is one of granular activated carbon, columnar activated carbon or activated carbon fiber. The hydraulic retention time of the filler layer in the empty tower is 0.5-2.0h based on the influent water.

[0049] The total outflow rate of the primary reaction tower 1 is 2-5 times the inflow rate, the outflow rate to the secondary UV reactor 7 is the same as the inflow rate, and the rest goes to the primary UV reactor 4; the outflow rate of the secondary reactor 2 is 3-10 times the inflow rate.

[0050] The primary UV reactor 4 and the secondary UV reactor 7 are both connected by ultraviolet lamps, reaction tubes and controllers. The ultraviolet lamps and reaction tubes are electrically connected to the controller. The reaction tubes are provided with quartz sleeves and sewage treatment tubes. The quartz sleeves are used to isolate the ultraviolet lamps and wastewater. The sewage treatment tubes are made of quartz, polytetrafluoroethylene or polyethylene. The volume of the sewage treatment tubes is based on a water residence time of 30-60s. The primary UV reactor and the secondary UV reactor are both common commercially available structures. The ultraviolet lamp of the primary UV reactor 4 is a lamp with a wavelength of 200-400nm ultraviolet light, preferably a medium-pressure ultraviolet lamp, and preferably has an installed power of 2000-3000W / m 3 The UV lamp of the secondary UV reactor 7 is a lamp with a wavelength of 200-400nm ultraviolet light, preferably a medium-pressure UV lamp, preferably with an installed power of 500-2000W / m 3 .

[0051] The pH value of the flocculation sedimentation tank 3 is 7-9, the coagulant is polyacrylamide, the addition concentration is 1-10 mg / L, and the hydraulic retention time is 2-4 h.

[0052] Example 1 The measured concentration of chlorobenzene in the wastewater of a chemical plant is 380-450 mg / L, and the COD is 500-600 mg / L. The bottom of the water sample contains chlorobenzene liquid phase, which is in the form of liquid beads and separated from the water phase. In this embodiment, the secondary reactor and the primary reaction tower are made of carbon steel lined with enamel. The purpose of adding the reagent is to achieve the control parameters. The specific addition method adopts the conventional addition method, and the implementation process is no longer described in detail. The lamps installed in the primary UV reactor and the secondary UV reactor are ultraviolet lamps that generate wavelengths of 200-400 nm.

[0053] The operating parameters are as follows: The oxidant is a hydrogen peroxide solution, and the dosage is 2000 mg / L in terms of pure hydrogen peroxide. The catalyst is a ferric chloride solution. The total iron concentration of the primary reaction tower 1 is controlled to be 100 mg / L, the hydraulic retention time is 2 h, the reaction temperature is 64±1°C, and hydrochloric acid is added to adjust the reaction pH to 2.2±0.1. Granular coconut shell activated carbon is selected as the filler layer 101, and the empty tower hydraulic retention time of the filler layer 101 is 1 h. The total amount of water discharged from the primary reaction tower 1 is 5 times the inlet flow rate, and the actual water discharge concentration of the primary reaction tower 1 is controlled to be 1500 mg / L in terms of pure hydrogen peroxide.

[0054] The UV power of the first-stage UV reactor 4 is 3000W / m 3 , the hydraulic retention time of the sewage treatment pipe is 120S.

[0055] The second oxidant is a hydrogen peroxide solution, the dosage is 500 mg / L based on pure hydrogen peroxide, the hydraulic retention time is 4 hours, the reaction temperature is 53±2°C, the reaction pH value is 2.9±0.1, and the total amount of water outlet from the secondary reactor 2 is 5 times the inlet flow rate.

[0056] The UV power of the secondary UV reactor 7 is 1000W / m 3 , the hydraulic retention time of the sewage treatment pipe is 60s.

[0057] Sodium hydroxide solution was added to flocculation sedimentation tank 3 to adjust the pH value to 8.5±0.5. The coagulant was cationic polyacrylamide with a concentration of 5 mg / L and a retention time of 3 h.

[0058] Operation results: The effluent chlorobenzene concentration of the primary reaction tower 1 is 20-100 mg / L, COD is 100-200 mg / L, and the color is yellow. The effluent chlorobenzene concentration of the flocculation sedimentation tank 3 is <0.1 mg / L, COD is 10-15 mg / L, turbidity is <2 NTU, SS (suspended solids) is 5-9 mg / L, and the color is colorless and transparent.

[0059] Example 2 The measured concentration of chlorobenzene in the wastewater produced by a rubber synthesis device is 250-300 mg / L, and the COD is 200-400 mg / L. The bottom of the water sample contains chlorobenzene liquid phase, which is in the form of liquid beads and separated from the water phase. In this embodiment, the secondary reactor is made of enamel, and the primary reaction tower is made of carbon steel lined with polytetrafluoroethylene. The purpose of adding the reagent is to achieve the control parameters. The specific addition method adopts the conventional addition method, and the implementation process is no longer described in detail. The lamps installed in the UV reactor are all ultraviolet lamps that generate wavelengths of 200-400nm. The operating parameters are as follows: The first oxidant is a hydrogen peroxide solution, the dosage of which is 1000 mg / L in terms of pure hydrogen peroxide, the catalyst is a ferric chloride solution, the total iron concentration of the primary reaction tower 1 is controlled to be 50 mg / L, the hydraulic retention time is 1 hour, the reaction temperature is 61±1°C, and hydrochloric acid is added to control the reaction pH value to be 2.4±0.1. The packing layer 101 selects granular coconut shell activated carbon, the hydraulic retention time of the empty tower of the packing layer is 0.5 hour, the total amount of water discharged from the primary reaction tower 1 is twice the water inlet flow rate, and the actual water discharge concentration of the primary reaction tower 1 is controlled to be 500 mg / L in terms of pure hydrogen peroxide.

[0060] The UV power of the first-stage UV reactor 4 is 2000W / m 3 , the hydraulic retention time of the sewage treatment pipe is 90s.

[0061] The second oxidant is a hydrogen peroxide solution, the dosage is 200 mg / L based on pure hydrogen peroxide, the hydraulic retention time is 3 h, the reaction temperature is 47±2°C, the reaction pH value is 2.6±0.1, and the total amount of water outlet from the secondary reactor 2 is 10 times the water inlet flow rate.

[0062] The UV power of the secondary UV reactor 7 is 1000W / m 3 , the hydraulic retention time of the sewage treatment pipe is 30s.

[0063] Sodium hydroxide solution was added to flocculation sedimentation tank 3 to adjust the pH value to 7.5±0.5. The coagulant was cationic polyacrylamide with a concentration of 10 mg / L and a retention time of 4 h.

[0064] Operation results: The effluent chlorobenzene concentration of the primary reaction tower 1 is 30-80mg / L, COD is 60-150mg / L, and the color is yellow. The effluent chlorobenzene concentration of the flocculation sedimentation tank 3 is <0.1mg / L, COD is 20-25mg / L, turbidity is <1.5NTU, SS is 6-10mg / L, and the color is colorless and transparent.

[0065] Example 3 Wastewater from a chemical production was mixed with recycled reverse osmosis concentrated water. The measured concentration of dichlorobenzene in the water was 50-100 mg / L, acetone 30-50 mg / L, and COD 300-500 mg / L. The bottom of the water sample contained a liquid phase, which was in the form of liquid beads and separated from the water phase. In this embodiment, the secondary reactor and the primary reaction tower were made of polyethylene. The purpose of adding the reagent was to achieve the control parameters. The specific addition method adopted the conventional addition method. The implementation process will not be described in detail. The lamps installed in the UV reactor were all ultraviolet lamps with a wavelength of 200-400 nm. The operating parameters are as follows: The first oxidant is a hydrogen peroxide solution, the dosage of which is 1500 mg / L in terms of pure hydrogen peroxide, the catalyst is a ferric chloride solution, the total iron concentration of the first-stage reaction tower 1 is controlled to be 80 mg / L, the hydraulic retention time is 3 hours, the reaction temperature is 62±1°C, sulfuric acid is added to control the reaction pH value to be 2.1±0.1, the packing layer 101 is granular coconut shell activated carbon, the hydraulic retention time of the packing layer empty tower is 2 hours, the total amount of water outlet from the first-stage reaction tower 1 is 3 times the water inlet flow rate, and the actual water outlet concentration of the first-stage reaction tower 1 is controlled to be 1000 mg / L in terms of pure hydrogen peroxide.

[0066] The UV power of the first-stage UV reactor 4 is 2500W / m 3 , the hydraulic retention time of the sewage treatment pipe is 60s.

[0067] The second oxidant is a hydrogen peroxide solution, the dosage is 50 mg / L based on pure hydrogen peroxide, the hydraulic retention time is 6 hours, the reaction temperature is 50±2°C, the reaction pH value is 2.8±0.1, and the total amount of water outlet from the secondary reactor 2 is 3 times the water inlet flow rate.

[0068] The UV power of the secondary UV reactor 7 is 2000W / m 3 , the sewage treatment pipe has a hydraulic retention time of 45S.

[0069] Potassium hydroxide solution was added to flocculation sedimentation tank 3 to adjust the pH value to 8.0±0.5. The coagulant was anionic polyacrylamide with a concentration of 1 mg / L and a retention time of 2 h. Operation results: The effluent dichlorobenzene concentration of the primary reaction tower 1 is 1-5 mg / L, COD is 150-200 mg / L, and the color is light yellow. The effluent dichlorobenzene concentration of the flocculation sedimentation tank 3 is less than 0.1 mg / L, monochlorobenzene concentration is less than 0.1 mg / L, COD is 10-30 mg / L, turbidity is less than 3 NTU, SS is 10-15 mg / L, and the color is colorless and transparent.

[0070] The effects of the present invention are further described below with reference to the comparative example of Example 1.

[0071] Comparative Example 1 The measured concentration of chlorobenzene in the wastewater of a chemical plant is 380-450 mg / L, and the COD is 500-600 mg / L. The bottom of the water sample contains chlorobenzene liquid phase in the form of liquid beads, which are separated from the water phase. The method and device for recycling supersaturated chlorobenzene-containing wastewater of the present invention are used in the same operation mode, except that no packing layer is set in the primary reaction tower 1, and the dosage of the oxidant 2 in the secondary reaction kettle 2 is increased. The operating parameters are as follows: The oxidant of the primary reaction tower 1 is hydrogen peroxide solution, and the dosage is 2000 mg / L based on pure hydrogen peroxide. The catalyst is ferric chloride solution, and the dosage concentration is 100 mg / L. The hydraulic retention time of the ferric chloride solution is 2h, 64±1℃, and sulfuric acid is added to control the reaction pH value to 2.2±0.1. No packing layer is set. The total amount of water outlet from the primary reaction tower 1 is 5 times the water inlet flow rate. The actual hydrogen peroxide content in the water outlet from the primary reaction tower 1 is 1600 mg / L.

[0072] The UV power of the first-stage UV reactor 4 is 3000W / m 3 , the hydraulic retention time of the sewage treatment pipe is 120S.

[0073] In the secondary reactor 2, the second oxidant is a hydrogen peroxide solution, the dosage is 1000 mg / L based on pure hydrogen peroxide, the hydraulic retention time is 4 h, the reaction temperature is 53±2°C, the reaction pH value is 2.9±0.1, and the total amount of water outlet from the secondary reactor 2 is 5 times the water inlet flow rate.

[0074] The UV power of the secondary UV reactor 7 is 1000W / m 3 , the hydraulic retention time of the sewage treatment pipe is 60S.

[0075] Sodium hydroxide solution was added to flocculation sedimentation tank 3 to adjust the pH value to 8.5±0.5. The coagulant was cationic polyacrylamide with a concentration of 5 mg / L and a retention time of 3 h.

[0076] Operation results: The effluent chlorobenzene concentration of the primary reaction tower 1 is 200-400 mg / L, COD is 500-600 mg / L, and the color is reddish brown. The effluent chlorobenzene concentration of the flocculation sedimentation tank 3 is 20-50 mg / L, COD is 150-200 mg / L, turbidity is 50-100 NTU, and the color is yellowish brown.

[0077] Compared with Example 1, in Comparative Example 1 without the filler of the present invention, the chlorobenzene and COD of the primary effluent increased and the color became darker. Even if the amount of oxidant added was increased later, the chlorobenzene and COD of the secondary effluent were still high, and the effective treatment of wastewater could not be achieved, and the direct discharge requirements of GB31571-2015 could not be met. The interception effect of the activated carbon filler in Example 1 promoted the effective degradation of wastewater.

[0078] Comparative Example 2 The measured concentration of chlorobenzene in the wastewater of a chemical plant is 380-450 mg / L, COD is 500-600 mg / L, and the bottom of the water sample contains chlorobenzene liquid phase in the form of liquid beads separated from the water phase. The method and device for recycling supersaturated chlorobenzene-containing wastewater of the present invention are basically the same in operation, except that the operation of the first-stage UV reactor 4 is stopped, and the operating parameters of other equipment are as follows: The first oxidant is a hydrogen peroxide solution, and the dosage is 2000 mg / L in terms of pure hydrogen peroxide. The catalyst is a ferrous chloride solution. The total iron concentration of the primary reaction tower 1 is controlled to be 100 mg / L, the hydraulic retention time is 2 h, the reaction temperature is 64±1°C, sulfuric acid is added to control the reaction pH value to be 2.2±0.1, and the packing layer 101 selects granular coconut shell activated carbon. The empty tower hydraulic retention time of the packing layer 101 is 1 h. The total amount of water effluent from the primary reaction tower 1 is 5 times the inlet flow rate, and the actual effluent concentration is 1500 mg / L in terms of pure hydrogen peroxide.

[0079] The UV power of the first-stage UV reactor 4 is 0W / m 3 , the hydraulic retention time of the sewage treatment pipe is 120S.

[0080] The second oxidant is a hydrogen peroxide solution, the dosage is 500 mg / L based on pure hydrogen peroxide, the hydraulic retention time is 4 hours, the reaction temperature is 53±2°C, the reaction pH value is 2.9±0.1, and the total amount of water outlet from the secondary reactor 2 is 5 times the inlet flow rate.

[0081] The UV power of the secondary UV reactor 7 is 1000W / m 3 , the hydraulic retention time of the sewage treatment pipe is 60s.

[0082] Sodium hydroxide solution was added to flocculation sedimentation tank 3 to adjust the pH value to 8.5±0.5. The coagulant was cationic polyacrylamide with a concentration of 5 mg / L and a retention time of 3 h.

[0083] Operation results: The chlorobenzene concentration of the effluent from the primary reaction tower 1 is 200-400 mg / L, COD is 450-550 mg / L, and the color is brown. The chlorobenzene concentration of the effluent from the flocculation sedimentation tank 3 is 50-100 mg / L, COD is 200-400 mg / L, turbidity is 50-100 NTU, and the color is dark brown. After 24 hours of operation, the chlorobenzene content in the effluent from the primary reaction tower 1 gradually increased, and chlorobenzene droplets were visible in the effluent.

[0084] Compared with Example 1, in Comparative Example 2, without the action of the primary UV reactor 4 of the present invention, even if the catalyst is replaced with ferrous salt to produce Fenton oxidation effect, the primary effluent chlorobenzene and COD are high, the color becomes darker, and the activated carbon filler is subsequently adsorbed saturated, and chlorobenzene droplets are visible to the naked eye in the effluent of the primary reaction tower 1, resulting in poor final effluent treatment effect. The primary UV reactor 4 causes the reaction to produce a large number of strong oxidizing free radicals, which plays a key role in promoting the dissolution of chlorobenzene and regenerating the activated carbon filler.

[0085] 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 supersaturated chlorobenzene-containing organic wastewater, characterized in that: The following steps are involved: 1) Separation and dissolution of undissolved chlorobenzene: The supersaturated chlorobenzene-containing organic wastewater enters the primary reaction tower (1) and is mixed with the effluent of the primary reaction tower (1) to form mixed wastewater. The mixed wastewater passes through the packing layer (101) from bottom to top in the reaction tower, and undissolved chlorobenzene is intercepted by the packing; 2) Oxidation of chlorobenzene and regeneration of packing: Acid solution, oxidant 1 and catalyst are added to the mixed wastewater flowing out from the top of the primary reaction tower (1), and then the mixed wastewater is oxidized in the primary UV reactor (4) and then enters the packing layer (101) of the primary reaction tower (1) to regenerate the packing layer (101). The mixed wastewater 2 in the effluent of the primary reaction tower (1) is refluxed to continue dissolving chlorobenzene, and the mixed wastewater 3 is sent to the secondary UV reactor (7); 3) Complete oxidation of chlorobenzene and its intermediates: adding oxidant 2 to mixed waste liquid 3, the mixed waste liquid 3 is recycled and degraded in the secondary UV reactor (7) and the secondary reactor (2), and after cyclic degradation, a mixed waste liquid 4 is formed and flows out of the secondary reactor (2); 4) Flocculation and sedimentation: Add alkali solution and coagulant to the mixed waste liquid No. 4, and subject the mixed waste liquid No. 4 to flocculation and sedimentation treatment before it meets the discharge standards.

2. The method for treating supersaturated chlorobenzene-containing organic wastewater according to claim 1, characterized in that: The primary reaction tower (1) and the secondary reaction kettle (2) are both made of one of polytetrafluoroethylene, polyethylene or enamel; based on the influent water, the hydraulic retention time of the primary reaction tower (1) is 1-3 hours, and the hydraulic retention time of the secondary reaction kettle (2) is 3-6 hours.

3. The method for treating supersaturated chlorobenzene-containing organic wastewater according to claim 1, characterized in that: The first oxidant is a hydrogen peroxide solution, the dosage of which is 1000-2000 mg / L in terms of pure hydrogen peroxide, and the concentration of the water discharged from the upper part of the primary reaction tower (1) is 500-1500 mg / L in terms of pure hydrogen peroxide. The second oxidant is one of ozone, persulfate or hydrogen peroxide solution, preferably hydrogen peroxide solution, and the dosage of which is 50-500 mg / L in terms of pure oxidant.

4. The method for treating supersaturated chlorobenzene-containing organic wastewater according to claim 1, characterized in that: The catalyst is a trivalent iron salt or a divalent iron salt, and the total iron concentration of the primary reaction tower (1) is 50-100 mg / L; the acid solution is sulfuric acid or hydrochloric acid, and the alkali solution is sodium hydroxide or potassium hydroxide.

5. The method for treating supersaturated chlorobenzene-containing organic wastewater according to claim 1, characterized in that: The reaction temperature of the primary reaction tower (1) is 60-65°C, and the reaction pH value of the primary reaction tower (1) is 2.0-2.5; the reaction temperature of the secondary reaction kettle (2) is 45-55°C, and the reaction pH value of the secondary reaction kettle (2) is 2.5-3.

0.

6. The method for treating supersaturated chlorobenzene-containing organic wastewater according to claim 1, characterized in that: The primary reaction tower (1) is provided with a packing layer (101), wherein the packing is one of granular activated carbon, columnar activated carbon or activated carbon fiber. The empty tower hydraulic retention time of the packing layer (101) is 0.5-2.0 h based on the influent water.

7. The method for treating supersaturated chlorobenzene-containing organic wastewater according to claim 1, characterized in that: The total outflow rate of the primary reaction tower (1) is 2-5 times the inflow rate of the water, the outflow rate to the secondary UV reactor (7) is the same as the inflow rate of the water, and the remainder goes to the primary UV reactor (4); the outflow rate of the secondary reactor (2) is 3-10 times the inflow rate of the water.

8. The method for treating supersaturated chlorobenzene-containing organic wastewater according to claim 1, characterized in that: The UV lamp of the primary UV reactor (4) is a lamp with a wavelength of 200-400nm, preferably a medium-pressure UV lamp, and preferably has an installed power of 2000-3000W / m 3 The UV lamp of the secondary UV reactor (7) is a lamp with a wavelength of 200-400nm UV light, preferably a medium-pressure UV lamp, preferably with an installed power of 500-2000W / m 3 .

9. The method for treating supersaturated chlorobenzene-containing organic wastewater according to claim 1, characterized in that: The pH value of the flocculation sedimentation tank (3) is 7-9, the coagulant is polyacrylamide, the addition concentration is 1-10 mg / L, and the hydraulic retention time is 2-4 h.

10. The device for treating supersaturated chlorobenzene-containing organic wastewater according to any one of claims 1 to 9, characterized in that: The invention comprises a primary reaction tower (1), a secondary reaction kettle (2) and a flocculation sedimentation tank (3) which are connected in sequence through pipelines. A packing layer (101) is arranged in the primary reaction tower (1). The primary reaction tower (1) is provided with a wastewater inlet pipeline (102) and a primary reaction tower outlet pipeline (103). The primary reaction tower outlet pipeline (103) is provided with an acid liquid feed pipeline (104), an oxidant first or catalyst feed pipeline (105) and a primary UV reactor (4). The pipeline between the primary reaction tower (1) and the secondary reaction kettle (2) is provided with an alkali liquid inlet pipeline (5), an oxidant second inlet pipeline (6) and a secondary UV reactor (7). The pipeline between the secondary reaction kettle (2) and the flocculation sedimentation tank (3) is provided with an alkali liquid inlet pipeline (8). The secondary reaction kettle (2) is also provided with a return water pipeline (9). The flocculation sedimentation tank (3) is provided with a treated wastewater outlet pipeline (10).

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