A device and method for treating PBAT production wastewater

Abstract

The present application relates to a kind of PBAT production wastewater treatment device and method, PBAT production wastewater treatment device includes adjusting tank, electro-catalytic oxidation pretreatment unit, hydrolytic acidification unit, biological oxidation unit, sludge-water clarifier and advanced treatment unit, adjusting tank side wall lower part is connected with the side wall lower part of electro-catalytic oxidation pretreatment unit by feed pipe and is communicated, and feed pump is arranged on feed pipe, electro-catalytic oxidation pretreatment unit, hydrolytic acidification unit, biological oxidation unit, sludge-water clarifier and advanced treatment unit are sequentially connected by pipeline;The bottom of biological oxidation unit is connected with the side wall lower part of hydrolytic acidification unit by first reflux pipe, the side wall lower part of sludge-water clarifier is connected with the side wall lower part of hydrolytic acidification unit by second reflux pipe, and first reflux pump and second reflux pump are respectively arranged on first reflux pipe and second reflux pipe.The present application is used for treating PBAT production wastewater by adopting physical and chemical, biochemical combination mode, and effluent COD is less than 100mg / L.

Description

Technical Field

[0001] This invention relates to the technical field of new petrochemical materials, specifically to a PBAT production wastewater treatment device and method. Background Technology

[0002] PBAT (polybutylene adipate / terephthalate) is a biodegradable plastic with excellent degradation and mechanical properties. Its molecular structure combines the characteristics of both aliphatic and aromatic polyesters, and it is widely used to replace traditional non-degradable plastics. PBAT and PLA together account for over 80% of my country's total biodegradable plastic production capacity, making them the industry's main products. This type of wastewater mainly originates from THF distillation tower recovery wastewater and scrubbing tower wastewater. The main pollutants are high-concentration organic compounds such as BDO (1,4-butanediol), THF (tetrahydrofuran), and n-butenol. The concentration of BDO is approximately 1500 mg / L, and the concentration of THF is approximately 3000 mg / L. The COD of both wastewater streams is approximately 9000 mg / L.

[0003] Currently, conventional wastewater treatment technology employs a combined process of Fenton oxidation pretreatment, anaerobic reactor, aerobic reactor, and advanced oxidation for deep treatment. The main drawbacks of this combined process are the large amount of chemical sludge produced by the Fenton oxidation pretreatment unit and the large dosage of reagents required. Incomplete pretreatment in the anaerobic reactor can lead to the escape of toxic substances, causing system shutdown. It also places high demands on the supporting utilities and the technical skills of operators. Conventional treatment methods suffer from poor actual operating results, high operating costs, and large amounts of hazardous waste. These problems also result in a large backlog of wastewater from production enterprises due to the inability to treat it promptly. Therefore, there is an urgent need to develop a mature and reliable treatment technology to ensure stable production operation. Summary of the Invention

[0004] In order to solve one or more technical problems existing in the prior art, the present invention provides a PBAT production wastewater treatment device and method.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: The present invention provides a PBAT production wastewater treatment device, including an equalization tank, an electrocatalytic oxidation pretreatment unit, a hydrolysis acidification unit, a biological oxidation unit, a sludge clarifier, and a deep treatment unit. The lower outlet of the side wall of the equalization tank is connected and communicated with the lower inlet of the side wall of the electrocatalytic oxidation pretreatment unit through a feed pipe. A feed pump is provided on the feed pipe. The electrocatalytic oxidation pretreatment unit, the hydrolysis acidification unit, the biological oxidation unit, the sludge clarifier, and the deep treatment unit are sequentially connected and communicated through pipelines. The bottom of the biological oxidation unit is connected and communicated with the lower inlet of the side wall of the hydrolysis acidification unit through a first reflux pipe. The lower side wall of the sludge clarifier is connected and communicated with the lower inlet of the side wall of the hydrolysis acidification unit through a second reflux pipe. A first reflux pump and a second reflux pump are respectively provided on the first reflux pipe and the second reflux pipe.

[0006] The beneficial effects of this invention are as follows: The PBAT production wastewater treatment device of this invention adopts a combination of physicochemical and biochemical methods to treat PBAT production wastewater. The main process reaction units should include an electrocatalytic oxidation pretreatment unit, a hydrolysis acidification unit, a high-efficiency biological oxidation unit, a sludge clarifier, and a deep treatment unit. Other auxiliary units include a regulating tank and a material feed pump. Specifically, the electrocatalytic oxidation pretreatment unit uses electrolytic adsorption and multiphase multi-element catalytic oxidation principles to detoxify the wastewater and ensure the stable operation of subsequent biochemical reactions; the hydrolysis acidification unit and the high-efficiency biological oxidation unit reduce the organic matter content in the wastewater through biochemical reactions; the deep treatment unit uses ozone contact oxidation, resulting in an effluent COD of less than 100 mg / L, meeting the emission standards of the "Petrochemical Industry Pollutant Emission Standard" (GB31571-2015). The PBAT production wastewater treatment device of this invention has a high degree of automation, is simple to manage, and can ensure system stability by monitoring various system indicators through online instruments.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, the bottom of the sludge clarifier is connected to a sludge treatment unit via a sludge discharge pipe, the sludge treatment unit including a screw press dewatering machine or a plate and frame filter press.

[0009] Furthermore, the tops of the regulating tank, the electrocatalytic oxidation pretreatment unit, the hydrolysis acidification unit, and the deep treatment unit are all connected to and communicate with the odor treatment unit via exhaust pipes; The odor treatment unit includes a water washing tower and an activated carbon adsorption tower connected in sequence by pipelines. Exhaust pipes at the top of the regulating tank, the electrocatalytic oxidation pretreatment unit, the hydrolysis acidification unit, and the deep treatment unit are all equipped with exhaust fans.

[0010] Furthermore, the regulating tank is equipped with a double-flange differential pressure level gauge, and a wastewater inlet pipe is connected to the upper side wall of the regulating tank. The wastewater inlet pipe is equipped with a first flow meter and an electric regulating valve.

[0011] Furthermore, the electrocatalytic oxidation pretreatment unit includes a first housing and a cathode plate, an anode plate, and a mixed packing material installed in the first housing. The cathode plate is made of graphite or steel, and the anode plate is an inert electrode. The operating voltage of the electrocatalytic oxidation pretreatment unit is less than 36V, and the electric field strength of the electrocatalytic oxidation pretreatment unit is 1~10V / cm; a first pressure sensor and a second flow meter are provided at both the inlet and outlet of the electrocatalytic oxidation pretreatment unit.

[0012] The beneficial effects of adopting the above-mentioned further scheme are: the electrocatalytic oxidation pretreatment unit adopts the principles of electrolytic adsorption and multiphase multi-element catalytic oxidation, which can specifically break down and de-chain toxic substances such as THF in wastewater, eliminate toxicity, and ensure the stable operation of the subsequent biological oxidation process system; during the operation phase, there are no external reagents added and no physicochemical sludge is discharged, reducing the cost of hazardous solid waste disposal.

[0013] Furthermore, the hydrolysis acidification unit includes a second housing and a semi-soft suspended packing layer installed inside the second housing, wherein the volume of the semi-soft suspended packing layer is 2 / 3 of the effective volume inside the hydrolysis acidification unit. The hydrolysis acidification unit is equipped with a first dissolved oxygen meter, an oxidation-reduction potential meter, and a pH meter.

[0014] The beneficial effects of adopting the above-mentioned further scheme are as follows: The main function of the hydrolysis acidification unit is to decompose large molecular organic matter such as BDO in wastewater into small molecular substances through the action of microbial extracellular enzymes, thereby improving the biodegradability of wastewater; at the same time, through acidification, small molecular organic matter is converted into intermediate products such as VFA (volatile fatty acids) during the fermentation process, providing easily degradable substrates for subsequent biochemical treatment.

[0015] Furthermore, the bio-oxidation unit includes a third chamber and a fibrous suspended packing layer installed inside the third chamber, the fibrous suspended packing layer having a specific surface area of ​​200 m². 2 / m 3 ~300m 2 / m 3 The volume of the fibrous suspended packing layer is 2 / 3 of the effective volume inside the bio-oxidation unit; The reflux ratio of the first reflux pump is 200%~250%; The third chamber contains a second dissolved oxygen meter.

[0016] The beneficial effects of adopting the above-mentioned further scheme are: the biological oxidation unit uses fibrous suspended packing material with a specific surface area of ​​200 m². 2 / m 3 ~300m 2 / m 3 A biofilm is attached to the packing material. The biofilm adsorbs and oxidizes organic matter in the wastewater, making the system more resistant to shocks, with less residual sludge and high COD degradation efficiency.

[0017] Furthermore, the mud clarifier is equipped with a mud level gauge, and the reflux ratio of the second reflux pump is 50%~100%.

[0018] The beneficial effects of adopting the above-mentioned further solutions are: by recirculating a large proportion of sludge mixed liquor, the COD load of the influent to the biological system is reduced, the sludge age is extended, the amount of excess sludge discharged is reduced, and the sludge disposal cost is significantly reduced.

[0019] Furthermore, the deep processing unit includes a fourth chamber and packing material installed inside the fourth chamber. The packing material includes one or more of zeolite, quartz sand and activated carbon. A second pressure sensor and a third flow meter are provided at both the inlet and outlet of the fourth chamber.

[0020] The beneficial effects of adopting the above-mentioned further scheme are: the deep treatment unit uses ozone contact oxidation as a deep treatment process, which can efficiently remove the remaining trace amounts of recalcitrant and highly harmful organic pollutants in the sewage, while significantly reducing the color of the sewage and the concentration of organic pollutants, ensuring that the effluent meets the requirements for discharge or reuse.

[0021] This invention also provides a method for treating PBAT production wastewater, implemented using the PBAT production wastewater treatment device described above, comprising the following steps: S1, PBAT production wastewater enters the equalization tank through the wastewater inlet pipe for water quality and quantity adjustment. The wastewater stays in the equalization tank for at least 12 hours. After water quality adjustment, the wastewater in the equalization tank is transported to the electrocatalytic oxidation pretreatment unit through the feed pipe and feed pump. The COD of the wastewater after treatment in the electrocatalytic oxidation pretreatment unit is below 4000 mg / L. S2, after undergoing electrocatalytic oxidation in the pretreatment unit, the wastewater flows sequentially into the hydrolysis acidification unit and the biological oxidation unit. The wastewater stays in the hydrolysis acidification unit for at least 16 hours, and the COD of the wastewater after treatment in the biological oxidation unit is below 500 mg / L. S3, the first reflux pump returns the end mixture of the biological oxidation unit to the inlet of the hydrolysis acidification unit, and reduces the COD load by mixing and diluting it with the inlet water of the hydrolysis acidification unit; S4, the effluent from the biological oxidation unit flows by gravity into the sludge clarifier. After sludge-water separation is achieved inside the sludge clarifier, the wet sludge settles into the sludge hopper at the bottom of the sludge clarifier. Part of it is returned to the inlet of the hydrolysis acidification unit via the second return pump, and part of it enters the sludge treatment unit for dewatering. The clear liquid at the top of the sludge clarifier is sent to the deep treatment unit for deep treatment through the upper outlet of the side wall before being discharged or reused. The COD of the clear liquid at the top of the sludge clarifier after treatment by the deep treatment unit is below 100 mg / L.

[0022] The beneficial effects of this invention are: the PBAT production wastewater treatment method of this invention is also applicable to Class I industrial wastewater with high COD and toxicity, ultimately achieving compliant discharge or reuse. The PBAT production wastewater treatment device and method of this invention are mainly applied in the petrochemical industry, fine chemical industry, and pharmaceutical industry. It is also applicable to Class I industrial wastewater with high COD and toxicity, ultimately achieving compliant discharge or reuse. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process structure of the PBAT production wastewater treatment device of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure and flow of the electrocatalytic oxidation pretreatment unit of the present invention; Figure 3 This is a schematic diagram of the structure and flow of the deep processing unit of the present invention.

[0025] The attached diagram lists the components represented by each number as follows: 1. Regulating tank; 11. Wastewater inlet pipe; 12. Feed pipe; 13. Feed pump; 2. Electrocatalytic oxidation pretreatment unit; 21. Basket filter; 22. Backwash water pump; 23. Air washing fan; 24. Power supply; 25. Mixing packing; 26. Cathode plate; 27. Anode plate; 3. Hydrolysis and acidification unit; 4. Biological oxidation unit; 41. First reflux pipe; 42. First reflux pump; 43. Aeration blower; 44. Fibrous suspended packing layer; 5. Sludge clarifier; 51. Second return pipe; 52. Second return pump; 53. Sludge discharge pipe; 6. Deep treatment unit; 61. Ozone generator; 62. Packing material; 63. Exhaust gas destroyer; 64. Exhaust gas emission pipeline; 7. Sludge treatment unit; 8. Odor treatment unit; 81. Exhaust pipe. Detailed Implementation

[0026] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0027] Example 1 like Figures 1-3 As shown, this embodiment of a PBAT production wastewater treatment device includes a regulating tank 1, an electrocatalytic oxidation pretreatment unit 2, a hydrolysis acidification unit 3, a biological oxidation unit 4, a sludge clarifier 5, and a deep treatment unit 6. The lower outlet of the side wall of the regulating tank 1 is connected to the lower inlet of the side wall of the electrocatalytic oxidation pretreatment unit 2 via a feed pipe 12. A feed pump 13 is provided on the feed pipe 12. The electrocatalytic oxidation pretreatment unit 2, the hydrolysis acidification unit 3, the biological oxidation unit 4, the sludge clarifier 5, and the deep treatment unit 6 are sequentially connected and communicated via pipelines. The bottom of the biological oxidation unit 4 is connected to the lower inlet of the side wall of the hydrolysis acidification unit 3 via a first reflux pipe 41. The lower side wall of the sludge clarifier 5 is connected to the lower inlet of the side wall of the hydrolysis acidification unit 3 via a second reflux pipe 51. A first reflux pump 42 and a second reflux pump 52 are respectively provided on the first reflux pipe 41 and the second reflux pipe 51.

[0028] like Figure 1 As shown, in a preferred embodiment, the bottom of the mud-water clarifier 5 is also connected to a sludge treatment unit 7 via a sludge discharge pipe 53. The sludge treatment unit 7 includes a screw press dewatering machine or a plate and frame filter press.

[0029] Furthermore, such as Figure 1 As shown, the tops of the regulating tank 1, the electrocatalytic oxidation pretreatment unit 2, the hydrolysis acidification unit 3, and the deep treatment unit 6 are all connected to and communicate with the odor treatment unit 8 through exhaust pipes 81; the odor treatment unit 8 includes a water washing tower and an activated carbon adsorption tower connected in sequence through pipelines, and an induced draft fan is provided on the exhaust pipes 81 at the tops of the regulating tank 1, the electrocatalytic oxidation pretreatment unit 2, the hydrolysis acidification unit 3, and the deep treatment unit 6.

[0030] Optionally, the regulating tank 1 is equipped with a dual-flange differential pressure level gauge, and a wastewater inlet pipe 11 is connected to the upper side wall of the regulating tank 1. The wastewater inlet pipe 11 is equipped with a first flow meter and an electric regulating valve. The dual-flange differential pressure level gauge, the first flow meter, and the electric regulating valve are used to regulate the feed rate and storage capacity in the regulating tank 1.

[0031] Preferably, the sludge clarifier 5 is equipped with a sludge level gauge, and the reflux ratio of the second reflux pump 52 is 50%~100%. By refluxing a large proportion of the sludge mixed liquor, the COD load of the influent to the biological system is reduced, the sludge age is extended, the amount of excess sludge discharged is reduced, and the sludge disposal cost is significantly reduced.

[0032] Specifically, the sludge clarifier 5 in this embodiment mainly functions to separate sludge from water in the effluent of the biological oxidation unit 4, reducing suspended solids in the effluent. The sludge clarifier 5 has an overflow weir at the top for discharging the clarified liquid and a sludge hopper at the bottom for collecting sludge. The design hydraulic load of the sludge clarifier 5 is 1m. 3 / (m 2 ·h).

[0033] In this embodiment, the PBAT production wastewater treatment device first enters a regulating tank for water quality and quantity adjustment. The effluent from the regulating tank is then pumped to the electrocatalytic oxidation pretreatment unit. The wastewater enters from the bottom of the electrocatalytic oxidation pretreatment unit. During the reaction, hydrogen and chlorine gases generated on both the anode and cathode plates are led to the odor treatment unit for purification through the exhaust port at the bottom of the unit. The electrocatalytic oxidation pretreatment unit undergoes periodic backwashing. The effluent from the electrocatalytic oxidation pretreatment unit flows by gravity through the outlet at the top of the unit into the hydrolysis acidification unit and the high-efficiency biological oxidation unit. A first reflux pump returns the end-of-pipe mixture from the high-efficiency biological oxidation unit to the inlet of the hydrolysis acidification unit, where it is mixed and diluted with the inlet water to reduce COD load. The effluent from the high-efficiency biological oxidation unit flows by gravity into the sludge clarifier. Inside the clarifier, sludge and water are separated. The wet sludge settles into the lower sludge hopper; part of it is returned to the inlet of the hydrolysis acidification unit via a second return pump, while the other part enters the clarified liquid and proceeds to the sludge treatment unit for dewatering. The clarified liquid from the clarifier is sent to the advanced treatment unit through the upper outlet. After reaction, the qualified effluent is discharged or reused. Odors generated by each unit are treated by the odor control unit and discharged in compliance with standards, or sent to the plant's combustion furnace for centralized disposal.

[0034] The PBAT production wastewater treatment device in this embodiment employs a combination of physicochemical and biochemical methods to treat PBAT production wastewater. The main process reaction units include an electrocatalytic oxidation pretreatment unit, a hydrolysis acidification unit, a high-efficiency biological oxidation unit, a sludge clarifier, and a deep treatment unit. Other auxiliary units include a regulating tank and a material feed pump. The electrocatalytic oxidation pretreatment unit utilizes electrolytic adsorption and multiphase multi-element catalytic oxidation principles to detoxify the wastewater and ensure stable operation of subsequent biochemical reactions. The hydrolysis acidification unit and the high-efficiency biological oxidation unit reduce the organic matter content in the wastewater through biochemical reactions. The deep treatment unit uses ozone contact oxidation, resulting in an effluent COD of less than 100 mg / L, meeting the emission standards of the "Petrochemical Industry Pollutant Emission Standard" (GB31571-2015). This PBAT production wastewater treatment device features a high degree of automation, simple management, and online instrument monitoring of various system indicators to ensure system stability.

[0035] Example 2 Based on Example 1, this example provides an alternative scheme for the electrocatalytic oxidation pretreatment unit 2.

[0036] The electrocatalytic oxidation pretreatment unit 2 in this embodiment includes a first housing and a cathode plate 26, an anode plate 27, and a mixed packing material 25 installed inside the first housing. Figure 2 As shown, the cathode plate 26 is made of graphite or steel, and the anode plate 27 is an inert electrode. The operating voltage of the electrocatalytic oxidation pretreatment unit 2 is below 36V, and the electric field strength of the electrocatalytic oxidation pretreatment unit 2 is 1~10V / cm. A first pressure sensor and a second flow meter are installed at both the inlet and outlet of the electrocatalytic oxidation pretreatment unit 2. The electrocatalytic oxidation pretreatment unit adopts the principles of electrolytic adsorption and multiphase multi-element catalytic oxidation to specifically break down and detoxify toxic substances such as THF in wastewater, ensuring the stable operation of the subsequent biological oxidation process system. During operation, no external reagents are added, and no physicochemical sludge is discharged, reducing hazardous waste disposal costs.

[0037] The electrocatalytic oxidation pretreatment unit 2 in this embodiment also includes a power supply 24, a backwash water pump 22, an air scrubbing fan 23, a basket filter 21, etc. Figure 2 As shown, the regulating tank 1 is connected to and communicates with the basket filter 21 via a pipeline, and the basket filter 21 is connected to the first housing via a pipeline. The cathode plate 26 and the anode plate 27 are respectively placed inside the mixed packing 25, and the cathode plate 26 and the anode plate 27 are respectively connected to the cathode and anode of the power supply 24. The mixed packing 25 is composed of a mixture of conductive and electrically insulating materials, some of which have adsorption functions. Commonly used packings include zeolite, quartz sand, activated carbon, graphite, peat, coke silica gel, etc. Generally, the ratio of conductive material to electrically insulating material in the mixed packing is 1:1 to 1:10, and the particle size of the mixed packing is 10 to 100 mesh. The air washing fan 23 is connected to and communicates with the first housing via a pipeline, and the hydrolysis acidification unit 3 is connected to and communicates with the first housing via a backwash pipe. A backwash water pump 22 is installed on the backwash pipe. In this embodiment, the first housing is made of insulating material and is equipped with an inlet, a backwash outlet, a tail gas outlet, and an outlet. The water inlet of the first tank is connected to the regulating tank via a pipeline, and the water outlet of the first tank is connected to the water inlet of the hydrolysis acidification unit via a pipeline.

[0038] In this embodiment, the electrocatalytic oxidation pretreatment unit 2 is an integrated device that specifically detoxifies the wastewater and reduces the COD influent load. The COD of the effluent after treatment by the electrocatalytic oxidation pretreatment unit 2 can be reduced to below 4000 mg / L.

[0039] Example 3 Based on Example 1 or Example 2, this embodiment provides an optional solution for the hydrolysis acidification unit 3.

[0040] The hydrolysis acidification unit 3 in this embodiment includes a second chamber and a semi-flexible suspended packing layer installed inside the second chamber. The volume of the semi-flexible suspended packing layer is 2 / 3 of the effective volume of the hydrolysis acidification unit 3. The hydrolysis acidification unit 3 is equipped with a first dissolved oxygen meter, an oxidation-reduction potential meter, and a pH meter for real-time monitoring and control. The main function of the hydrolysis acidification unit is to decompose large organic molecules such as BDO in wastewater into smaller molecules through the action of extracellular enzymes of microorganisms, thereby improving the biodegradability of the wastewater. At the same time, through acidification, small organic molecules are converted into intermediate products such as VFA (volatile fatty acids) during fermentation, providing easily degradable substrates for subsequent biochemical treatment.

[0041] In this embodiment, the second tank adopts bottom water inlet, the top of the second tank adopts serrated overflow weir water outlet, and the bottom of the second tank is provided with tree branch water distribution pipe to ensure uniform water distribution.

[0042] Example 4 Based on any of the above embodiments, this embodiment provides an optional solution for the biological oxidation unit 4.

[0043] The bio-oxidation unit 4 in this embodiment includes a third housing and a fibrous suspended packing layer 44 installed inside the third housing. The specific surface area of ​​the fibrous suspended packing layer 44 is 200 m². 2 / m 3 ~300m 2 / m 3 The volume of the fibrous suspended packing layer is 2 / 3 of the effective volume inside the biological oxidation unit 4; the reflux ratio of the first reflux pump is 200%~250%; a second dissolved oxygen meter is installed in the third chamber for pre-monitoring and control. The high-efficiency biological oxidation unit uses fibrous suspended packing with a specific surface area of ​​200 m². 2 / m 3 ~300m 2 / m 3 A biofilm is attached to the packing material. The biofilm adsorbs and oxidizes organic matter in the wastewater, making the system more resistant to shocks, with less residual sludge and high COD degradation efficiency.

[0044] The biological oxidation unit in this embodiment adopts an integrated contact oxidation process device. The biological oxidation unit in this embodiment also includes an aeration blower 43, which is connected to the interior of the third housing via a pipeline. Figure 1 As shown in the figure. In this embodiment, a first reflux pump is installed at the end of the biological oxidation unit to dilute the influent and reduce the COD load, with a designed reflux ratio of 200%~250%.

[0045] Example 5 Based on any of the above embodiments, this embodiment provides an optional solution for the depth processing unit 6.

[0046] like Figure 3 As shown, the deep processing unit 6 in this embodiment includes an ozone generator 61, an exhaust gas destroyer 63, an exhaust gas emission pipe 64, a fourth housing, and a packing material 62 installed inside the fourth housing, as shown. Figure 3 As shown, the ozone generator 61 is connected to the bottom of the fourth chamber via a pipeline, and the top of the fourth chamber is connected to the exhaust gas emission pipeline 64. An exhaust gas destructor 63 is installed on the exhaust gas emission pipeline 64. The packing material includes one or more of zeolite, quartz sand, and activated carbon. A second pressure sensor and a third flow meter are installed at both the inlet and outlet of the fourth chamber to achieve online monitoring and control. The advanced treatment unit uses ozone contact oxidation as an advanced treatment process, which can efficiently remove residual trace amounts of recalcitrant and highly hazardous organic pollutants in wastewater, while significantly reducing wastewater color and the concentration of organic pollutants, ensuring that the effluent meets discharge or reuse standards.

[0047] In this embodiment, the advanced treatment unit 6 employs an integrated ozone contact oxidation process, reducing the COD of the wastewater after treatment to below 100 mg / L. The fourth tank in this embodiment is equipped with a backwash inlet and a tail gas outlet.

[0048] In the process described, an ozone concentration detector is also installed on the exhaust gas emission pipe 64.

[0049] Example 6 This embodiment provides a method for treating PBAT production wastewater, which is implemented using the PBAT production wastewater treatment device described above, and includes the following steps: S1, PBAT production wastewater enters equalization tank 1 through wastewater inlet pipe 11 for water quality and quantity adjustment. The wastewater stays in equalization tank 1 for at least 12 hours. After water quality adjustment, the wastewater in equalization tank 1 is transported to electrocatalytic oxidation pretreatment unit 2 through feed pipe 12 and feed pump 13. The COD of the wastewater after treatment in electrocatalytic oxidation pretreatment unit 2 is below 4000 mg / L. S2, after undergoing electrocatalytic oxidation reaction in the electrocatalytic oxidation pretreatment unit 2, the wastewater flows sequentially into the hydrolysis acidification unit 3 and the biological oxidation unit 4. The residence time of the wastewater in the hydrolysis acidification unit 3 is at least 16 hours, and the COD of the wastewater after treatment in the biological oxidation unit 4 is below 500 mg / L. S3, the first reflux pump 42 refluxes the end mixture of the biological oxidation unit 4 back to the inlet of the hydrolysis acidification unit 3, and reduces the COD load by mixing and diluting it with the inlet water of the hydrolysis acidification unit 3; S4, the effluent from the biological oxidation unit 4 flows by gravity into the sludge clarifier 5. After sludge-water separation is achieved inside the sludge clarifier 5, the wet sludge settles into the lower sludge hopper of the sludge clarifier 5. Part of it is returned to the inlet of the hydrolysis acidification unit 3 by the second return pump 52, and part of it enters the sludge treatment unit 7 for dewatering. The clear liquid at the top of the sludge clarifier 5 is sent to the deep treatment unit 6 through the upper outlet of the side wall for deep treatment before being discharged or reused. The COD of the clear liquid at the top of the sludge clarifier 5 after treatment by the deep treatment unit 6 is below 100 mg / L.

[0050] The PBAT production wastewater treatment method in this embodiment is also applicable to Class I industrial wastewater with high COD and toxicity, ultimately achieving compliant discharge or reuse. The PBAT production wastewater treatment device and method in this embodiment are mainly applied in the petrochemical, fine chemical, and pharmaceutical industries. It is also applicable to Class I industrial wastewater with high COD and toxicity, ultimately achieving compliant discharge or reuse.

[0051] Finally, it should be noted that although specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative of a new process application for a PBAT production wastewater treatment system, and do not limit the scope of application of the present invention. Equivalent modifications and variations made by those skilled in the art and of the process route in accordance with the ideas and concepts of the present invention should be covered within the scope of protection of the claims of the present invention.

[0052] In the description of this invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0053] Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0056] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A PBAT production wastewater treatment device, characterized in that, The system includes a regulating tank, an electrocatalytic oxidation pretreatment unit, a hydrolysis acidification unit, a biological oxidation unit, a sludge clarifier, and a deep treatment unit. The lower outlet of the regulating tank's side wall is connected to the lower inlet of the electrocatalytic oxidation pretreatment unit's side wall via a feed pipe. A feed pump is installed on the feed pipe. The electrocatalytic oxidation pretreatment unit, the hydrolysis acidification unit, the biological oxidation unit, the sludge clarifier, and the deep treatment unit are sequentially connected and interconnected via pipelines. The bottom of the biological oxidation unit is connected to the lower inlet of the hydrolysis acidification unit's side wall via a first reflux pipe. The lower side wall of the sludge clarifier is connected to the lower inlet of the hydrolysis acidification unit's side wall via a second reflux pipe. A first reflux pump and a second reflux pump are respectively installed on the first reflux pipe and the second reflux pipe.

2. The PBAT production wastewater treatment device according to claim 1, characterized in that, The bottom of the sludge clarifier is also connected to a sludge treatment unit via a sludge discharge pipe. The sludge treatment unit includes a screw press dewatering machine or a plate and frame filter press.

3. The PBAT production wastewater treatment device according to claim 1, characterized in that, The tops of the regulating tank, electrocatalytic oxidation pretreatment unit, hydrolysis acidification unit, and deep treatment unit are all connected to and communicate with the odor treatment unit via exhaust pipes. The odor treatment unit includes a water washing tower and an activated carbon adsorption tower connected in sequence by pipelines. Exhaust pipes at the top of the regulating tank, the electrocatalytic oxidation pretreatment unit, the hydrolysis acidification unit, and the deep treatment unit are all equipped with exhaust fans.

4. The PBAT production wastewater treatment device according to claim 1, characterized in that, The regulating tank is equipped with a double-flange differential pressure level gauge, and a wastewater inlet pipe is connected to the upper side wall of the regulating tank. The wastewater inlet pipe is equipped with a first flow meter and an electric regulating valve.

5. The PBAT production wastewater treatment device according to claim 1, characterized in that, The electrocatalytic oxidation pretreatment unit includes a first chamber and a cathode plate, an anode plate, and mixed packing installed in the first chamber. The cathode plate is made of graphite or steel, and the anode plate is an inert electrode. The operating voltage of the electrocatalytic oxidation pretreatment unit is less than 36V, and the electric field strength of the electrocatalytic oxidation pretreatment unit is 1~10V / cm; a first pressure sensor and a second flow meter are provided at both the inlet and outlet of the electrocatalytic oxidation pretreatment unit.

6. The PBAT production wastewater treatment device according to claim 1, characterized in that, The hydrolysis acidification unit includes a second housing and a semi-soft suspended packing layer installed inside the second housing. The volume of the semi-soft suspended packing layer is 2 / 3 of the effective volume inside the hydrolysis acidification unit. The hydrolysis acidification unit is equipped with a first dissolved oxygen meter, an oxidation-reduction potential meter, and a pH meter.

7. The PBAT production wastewater treatment device according to claim 1, characterized in that, The bio-oxidation unit includes a third chamber and a fibrous suspended packing layer installed inside the third chamber. The specific surface area of ​​the fibrous suspended packing layer is 200 m². 2 / m 3 ~300m 2 / m 3 The volume of the fibrous suspended packing layer is 2 / 3 of the effective volume inside the bio-oxidation unit; The reflux ratio of the first reflux pump is 200%~250%; The third chamber contains a second dissolved oxygen meter.

8. The PBAT production wastewater treatment device according to claim 1, characterized in that, The mud clarifier is equipped with a mud level gauge, and the reflux ratio of the second reflux pump is 50%~100%.

9. The PBAT production wastewater treatment device according to claim 1, characterized in that, The deep processing unit includes a fourth chamber and packing material installed inside the fourth chamber. The packing material includes one or more of zeolite, quartz sand and activated carbon. A second pressure sensor and a third flow meter are installed at both the inlet and outlet of the fourth chamber.

10. A method for treating PBAT production wastewater, characterized in that, The treatment of PBAT production wastewater, as described in any one of claims 1 to 9, includes the following steps: S1, PBAT production wastewater enters the equalization tank through the wastewater inlet pipe for water quality and quantity adjustment. The wastewater stays in the equalization tank for at least 12 hours. After water quality adjustment, the wastewater in the equalization tank is transported to the electrocatalytic oxidation pretreatment unit through the feed pipe and feed pump. The COD of the wastewater after treatment in the electrocatalytic oxidation pretreatment unit is below 4000 mg / L. S2, after undergoing electrocatalytic oxidation in the pretreatment unit, the wastewater flows sequentially into the hydrolysis acidification unit and the biological oxidation unit. The wastewater stays in the hydrolysis acidification unit for at least 16 hours, and the COD of the wastewater after treatment in the biological oxidation unit is below 500 mg / L. S3, the first reflux pump returns the end mixture of the biological oxidation unit to the inlet of the hydrolysis acidification unit, and reduces the COD load by mixing and diluting it with the inlet water of the hydrolysis acidification unit; S4, the effluent from the biological oxidation unit flows by gravity into the sludge clarifier. After sludge-water separation is achieved inside the sludge clarifier, the wet sludge settles into the sludge hopper at the bottom of the sludge clarifier. Part of it is returned to the inlet of the hydrolysis acidification unit via the second return pump, and part of it enters the sludge treatment unit for dewatering. The clear liquid at the top of the sludge clarifier is sent to the deep treatment unit for deep treatment through the upper outlet of the side wall before being discharged or reused. The COD of the clear liquid at the top of the sludge clarifier after treatment by the deep treatment unit is below 100 mg / L.

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