Coking wastewater conditioning pretreatment catalytic oxidation device and method

Abstract

The application discloses a coking wastewater conditioning pretreatment catalytic oxidation device and method, and relates to the technical field of industrial wastewater treatment. The device comprises a catalytic oxidation reaction tower, wherein a vertical flow reaction pipe is arranged in the catalytic oxidation reaction tower; the vertical flow reaction pipe comprises a gas distribution zone, a catalytic zone and a catalyst backfall zone which are sequentially communicated from bottom to top, the diameter of the catalyst backfall zone is larger than that of the catalytic zone; the gas distribution zone is provided with an aeration pipe, the aeration pipe is communicated with an ozone generator; a water distribution pipe is arranged below the gas distribution zone, the water distribution pipe is communicated with a raw water conveying device; a raw water circulating inlet is arranged below the gas distribution zone, a raw water circulating outlet is arranged above the catalyst backfall zone, and the raw water circulating inlet and the raw water circulating outlet are communicated through a forced circulation pump. The catalyst reciprocally moves up and down in the catalytic zone; in the range of the catalyst backfall zone, the upward floating catalyst falls back to the catalytic zone, thereby realizing efficient cyclic utilization of the catalyst. The forced external circulation system increases the residence time of the raw water in the catalytic oxidation reaction tower.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment technology, and in particular to a catalytic oxidation device and method for conditioning and pretreatment of coking wastewater. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Coking wastewater is mainly generated during the high-temperature dry distillation, purification, and condensation processes in coking and gasification. Additionally, by-product recovery also produces coking wastewater. Coking wastewater has unique characteristics, with high pollutant content, containing recalcitrant organic compounds such as phenols and cyanides, and exhibiting poor biodegradability. Conventional coking wastewater pretreatment processes are complex and require large amounts of chemicals, sometimes failing to meet the influent requirements of the biological treatment system. Often, large amounts of dilution water are added to reduce COD and toxic substances to meet the influent requirements of the biological treatment system.

[0004] In the prior art, the patent application CN114471585A, entitled "An ozone catalyst with acetate as a precursor and its preparation method and application", provides an ozone catalyst that can reduce the COD content of wastewater such as phenol wastewater and malonic acid wastewater.

[0005] However, there is still a lack of technical solutions for improving wastewater treatment equipment in order to increase the contact efficiency between pollutants in wastewater and catalysts, or to improve the utilization rate of catalysts. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a catalytic oxidation device and method for conditioning and pretreatment of coking wastewater. A vertical flow reaction tube is fixedly installed inside the catalytic oxidation reaction tower, causing the catalyst to move up and down reciprocally within the reaction tube. A circulation device is used to increase the contact time between the raw water and the catalyst, thereby improving the utilization rate of the catalyst.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] The first aspect of this invention provides a catalytic oxidation device for conditioning and pretreatment of coking wastewater, comprising:

[0009] A catalytic oxidation reaction tower, which is equipped with a vertical flow reaction tube;

[0010] The vertical flow reaction tube includes a gas distribution zone, a catalytic zone, and a catalyst fall-off zone connected sequentially from bottom to top. The diameter of the gas distribution zone is larger than the diameter of the catalytic zone, and the diameter of the catalyst fall-off zone is larger than the diameter of the catalytic zone. Within the catalytic zone, the catalyst moves up and down reciprocally. Within the catalyst fall-off zone, the upward-floating catalyst falls back into the catalytic zone.

[0011] An aeration pipe is installed in the gas distribution zone, and the aeration pipe is connected to an ozone generator outside the catalytic oxidation reaction tower; a water distribution pipe is installed below the gas distribution zone, and the water distribution pipe is connected to a raw water conveying device outside the catalytic oxidation reaction tower.

[0012] A raw water circulation inlet is provided below the gas distribution zone, and a raw water circulation outlet is provided above the catalyst fall-off zone. The raw water circulation inlet and the raw water circulation outlet are connected by a forced circulation pump.

[0013] Optionally, the catalytic oxidation reaction tower is equipped with multiple vertical flow reaction tubes, all of which are at the same height. The vertical flow reaction tubes are spaced at a predetermined distance from the inner surface of the catalytic oxidation reaction tower and are connected to the inner surface of the catalytic oxidation reaction tower via a support frame, so that the vertical flow reaction tubes are in a suspended state.

[0014] Optionally, a catalyst feed pipe is provided in the catalyst fallback zone, and the catalyst feed pipe is connected to the catalyst inlet outside the catalytic oxidation reaction tower.

[0015] Optionally, the inner wall of the catalytic zone of the vertical flow reaction tube is connected to an upwardly inclined guide plate, with guide plates of different heights arranged alternately.

[0016] Optionally, a raw water outlet is provided above the raw water circulation outlet for discharging wastewater that has undergone catalytic oxidation.

[0017] Optionally, a mist eliminator is provided above the raw water outlet, and a tail gas outlet is provided above the mist eliminator. The tail gas outlet is connected to the aeration pipe from the outside of the catalytic oxidation reaction tower.

[0018] Optionally, a gas flow meter is installed between the ozone generator and the aeration pipe.

[0019] Optionally, the exhaust gas outlet is connected to a gas conveying fan, and the gas conveying fan is connected to the inlet of the gas flow meter.

[0020] Optionally, a backwash water pipe is provided above the gas distribution zone of the vertical flow reaction pipe, and the backwash water pipe is connected to the backwash water inlet outside the catalytic oxidation reaction tower 1; a backwash water outlet is provided between the raw water outlet and the mist eliminator, and the backwash water inlet and the backwash water outlet are connected to the backwashing device.

[0021] Optionally, the catalytic oxidation reaction tower is provided with multiple vertical flow reaction tubes, and the multiple vertical flow reaction tubes are at the same height.

[0022] Optionally, the raw water outlet can be set at multiple heights.

[0023] Secondly, the present invention provides a method for catalytic oxidation of coking wastewater based on the above-mentioned coking wastewater conditioning and pretreatment catalytic oxidation device, comprising the following steps:

[0024] S1. Untreated coking wastewater is introduced into the water distribution pipe and mixed with the forced circulating raw water introduced into the raw water circulation inlet to form mixed raw water, which flows upward into the vertical flow reaction pipe.

[0025] S2. The mixed raw water mixes with the ozone gas input through the aeration pipe in the aeration zone to form a gas-water mixture, which flows upward into the catalytic zone.

[0026] S3. The carbonated beverage mixture comes into contact with the catalyst moving up and down in the catalytic zone and undergoes an ozone catalytic reaction.

[0027] S4. The gas-water mixture undergoes gas-water separation in the catalyst fall-off zone, and the separated treated water enters the raw water circulation outlet to become forced circulating raw water.

[0028] S5. The treated water that meets the standards flows out through the raw water outlet.

[0029] Optionally, in S4, the exhaust gas after gas-water separation is treated by a mist eliminator and then discharged through the exhaust gas outlet before entering the aeration pipe for recycling.

[0030] Optionally, in S3, the residence time of the steam-water mixture in the vertical reaction tube is increased under the action of the guide plate in the catalytic zone, and a mass transfer process occurs with the catalyst.

[0031] Optionally, in S5, the COD level is detected to determine whether the treatment meets the standards. If the treatment meets the standards, the raw water outlet is opened.

[0032] The beneficial effects of this invention are as follows:

[0033] 1. This invention features a suspended vertical flow reaction tube within the catalytic oxidation reaction tower. The catalyst is carried to the top of the suspended vertical flow reaction tube by an upward high-speed water flow. As the diameter of the top of the suspended vertical flow reaction tube increases, the water flow velocity slows down, and the catalyst falls back into the suspended vertical flow reaction tube, where it is carried back to the top by the high-speed water flow. This repeated motion creates a forced circulation, ensuring that the catalyst remains within the suspended vertical flow reaction tube and maintains full contact with the water to prevent it from settling to the bottom, thus achieving efficient recycling of the catalyst.

[0034] 2. The present invention is equipped with a forced external circulation system and circulation pump outside the catalytic oxidation reaction tower, which increases the residence time of raw water in the catalytic oxidation reaction tower by 30-60 minutes, thereby achieving efficient circulation treatment of raw water.

[0035] 3. The present invention features an ozone-raw water mixing buffer zone at the bottom of the suspended vertical flow reaction tube. Aeration pipes and water distribution pipes are positioned within this buffer zone, ensuring uniform mixing of ozone and raw water before they enter the suspended vertical flow reaction tube, thus improving ozone dissolution rate. The aeration pipes provide 360° omnidirectional aeration, further enhancing ozone mixing before entry. A mist-collecting zone is located at the top of the catalytic oxidation reaction tower to remove moisture and particulate matter carried by the ozone exhaust gas before it enters the subsequent ozone exhaust gas recovery process and is reintroduced into the ozone generation system, forming a closed-loop system and achieving efficient ozone dissolution and closed-loop utilization. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0037] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0038] Figure 1 This is a schematic diagram of the coking wastewater conditioning and pretreatment catalytic oxidation device in a specific embodiment.

[0039] The components include: 1. Catalytic oxidation reaction tower; 2. Vertical flow reaction pipe; 3. Catalyst; 4. Aeration pipe; 5. Ozone generator; 6. Water distribution pipe; 7. Raw water conveying device; 8. Raw water circulation inlet; 9. Raw water circulation outlet; 11. Forced circulation pump; 12. Catalyst inlet; 13. Raw water outlet; 14. Mist eliminator; 15. Tail gas outlet; 16. Gas conveying fan; 17. Gas flow meter; 18. Oxygen storage tank; 19. Backwash water inlet; 20. Backwash water outlet; 21. Gas distribution zone; 22. Catalytic zone; 23. Catalyst fall-off zone; 24. Baffle plate. Detailed Implementation

[0040] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0041] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] Example 1

[0043] A catalytic oxidation device for conditioning and pretreatment of coking wastewater, such as Figure 1 As shown, it includes:

[0044] Catalytic oxidation reaction tower 1, and a vertical flow reaction tube 2 is provided in catalytic oxidation reaction tower 1;

[0045] The vertical flow reaction tube 2 includes a gas distribution zone 21, a catalytic zone 22, and a catalyst fall-off zone 23 connected sequentially from bottom to top. The diameter of the gas distribution zone 21 is larger than the diameter of the catalytic zone 22, and the diameter of the catalyst fall-off zone 23 is larger than the diameter of the catalytic zone 22. Within the catalytic zone 22, the catalyst 3 moves up and down. Within the catalyst fall-off zone 23, the upward-floating catalyst 3 falls back to the catalytic zone 22.

[0046] An aeration pipe 4 is installed in the gas distribution zone 21, and the aeration pipe 4 is connected to the ozone generator 5 outside the catalytic oxidation reaction tower 1; a water distribution pipe 6 is installed below the gas distribution zone 21, and the water distribution pipe 6 is connected to the raw water conveying device 7 outside the catalytic oxidation reaction tower 1.

[0047] A raw water circulation inlet 8 is provided below the gas distribution zone 21, and a raw water circulation outlet 9 is provided above the catalyst fall-off zone 23. The raw water circulation inlet 8 and the raw water circulation outlet 9 are connected by a forced circulation pump 11, and a valve is provided at the water inlet end of the forced circulation pump 11.

[0048] With the above setup, since the diameter of the catalyst fall-off zone 23 is larger than that of the catalyst zone 22 below, the raw water flow velocity will be lower than that of the catalyst zone 22. Therefore, the impact force of the flowing raw water on the catalyst 3 particles in the catalyst fall-off zone 23 is reduced, insufficient to drive the catalyst 3 particles to continue rising, and thus the catalyst 3 particles fall back. The falling catalyst 3 particles, carrying a downward initial velocity, enter the catalyst zone 22, and under the impact of the flowing raw water, stop their downward trend and rise to the catalyst fall-off zone 23, achieving forced circulation through the up-and-down reciprocating motion of the catalyst 3 particles. Thus, the catalyst 3 particles are constantly suspended in the raw water for mass transfer, achieving efficient utilization of the catalyst 3. On the other hand, a forced external circulation system of raw water is formed between the raw water circulation inlet 8 and the raw water circulation outlet 9, increasing the residence time of the raw water in the catalytic oxidation reaction tower 1 and achieving efficient circulation treatment of the raw water.

[0049] A catalyst feed pipe is provided in the catalyst fall-off zone 23. The catalyst feed pipe is connected to the catalyst inlet 12 outside the catalytic oxidation reaction tower 1. The catalyst inlet 12 is a feeding port. The catalyst feed pipe opens in the catalyst fall-off zone 23 to add catalyst 3 to the reaction device.

[0050] The inner wall of the catalytic zone 22 of the vertical flow reaction tube 2 is connected to an upwardly inclined guide plate 24, with guide plates 24 at different heights arranged alternately. The guide plate 24 has a turbulence effect, which can increase the residence time of ozone in the vertical flow reaction tube 2, thereby increasing the reaction time of ozone, catalyst 3 and raw water in the vertical flow reaction tube 2 and improving the pollutant degradation rate. At the same time, the guide plate 24 can adjust the flow field distribution in the vertical flow reaction tube 2, suppress eddies, and improve the mass transfer efficiency in the vertical flow reaction tube 2.

[0051] The guide plates 24 are staggered on both sides inside the vertical flow reaction tube 2 and are inclined toward the top of the vertical flow reaction tube 2 at an angle of 20 to 70 degrees, preferably 30 to 60 degrees.

[0052] The aeration angle of the aeration pipe 4 is set to 360° for all-round aeration, and the number is 2 to 10, preferably 4 to 8.

[0053] The water distribution pipes 6 are configured so that the water flow direction is upward, and the number is 2 to 10, preferably 4 to 8.

[0054] Raw water outlet 13 is located above raw water circulation outlet 9 and is used to discharge wastewater that has undergone catalytic oxidation. A mist eliminator 14 is installed above raw water outlet 13, and a tail gas outlet 15 is installed above mist eliminator 14. The tail gas outlet 15 is connected to aeration pipe 4 from the outside of catalytic oxidation reaction tower 1. Mist eliminator 14 can remove moisture, particulate matter, etc. carried by ozone tail gas and enter the subsequent ozone tail gas recovery process. Through the recovery blower, i.e. gas conveying blower 16, the gas is reintroduced into the ozone generation system to form a closed loop system, realizing the efficient dissolution and closed-loop utilization of ozone.

[0055] A gas flow meter 17 is installed between the ozone generator 5 and the aeration pipe 4 to supply ozone quantitatively to the vertical flow reaction pipe 2.

[0056] The exhaust outlet 15 is connected to the gas conveying fan 16, and the gas conveying fan 16 is connected to the inlet end of the gas flow meter 17 and connected to the pipeline that supplies gas to the aeration pipe 4. That is, the gas conveying fan 16 is located on a branch of the gas supply pipeline; on the branch of the gas supply pipeline, valves are respectively installed at the inlet end and the outlet end of the gas conveying fan 16; on the main gas supply pipeline, a valve is installed at the inlet end of the gas flow meter 17.

[0057] Ozone generator 5 is connected to oxygen storage tank 18 and is used to output ozone gas.

[0058] A backwash water pipe is installed above the gas distribution zone 21 of the vertical flow reaction pipe 2, and the backwash water pipe is connected to the backwash water inlet 19 on the outside of the catalytic oxidation reaction tower 1; a backwash water outlet 20 is installed between the raw water outlet 13 and the mist eliminator 14, and the backwash water inlet 19 and the backwash water outlet 20 are connected to the backwashing device.

[0059] Backwash water, also known as backflushing, is a process in which water flows through the reaction device to flush away blockages and reduce head loss. In this embodiment, the backwash water inlet 19 and backwash water outlet 20 are not opened during catalytic oxidation. During device maintenance, the backwash water inlet 19 and backwash water outlet 20 are opened to perform backwashing in the vertical reaction tube 2.

[0060] The catalytic oxidation reaction tower 1 is equipped with multiple vertical flow reaction tubes 2, all of which are at the same height. The multiple vertical flow reaction tubes 2 make the flow field distribution within the entire catalytic oxidation reaction tower 1 more uniform, thereby improving the processing capacity and effect of the catalytic oxidation reaction tower 1. The vertical flow reaction tubes 2 are spaced at a predetermined distance from the inner surface of the catalytic oxidation reaction tower 1 and are connected to the inner surface of the catalytic oxidation reaction tower 1 through a support frame, so that the vertical flow reaction tubes 2 are fixedly supported inside the catalytic oxidation reaction tower 1. Both the upper and lower ends of the vertical flow reaction tubes 2 are open to ensure smooth water circulation.

[0061] The raw water outlet 13 has multiple outlets at different heights. By opening the raw water outlets 13 at different heights, the water level below the mist trap 14, the height of the raw water outlet 13, and the relative height between the raw water circulation outlet 9 can be flexibly adjusted.

[0062] Example 2

[0063] The coking wastewater conditioning and pretreatment catalytic oxidation method based on the coking wastewater conditioning and pretreatment catalytic oxidation device in Example 1 includes the following steps:

[0064] S1. Untreated coking wastewater is input into the water distribution pipe 6 and mixed with the forced circulating raw water input into the raw water circulation inlet 8 to form mixed raw water, which flows upward into the vertical flow reaction pipe 2.

[0065] S2. The mixed raw water is mixed with the ozone gas input from the aeration pipe 4 in the aeration zone 21 to form a gas-water mixture, which flows upward into the catalytic zone 22.

[0066] S3, the carbonated beverage mixture comes into contact with the catalyst 3 moving up and down in the catalytic zone 22 to carry out an ozone catalytic reaction;

[0067] S4. The gas-water mixture undergoes gas-water separation in the catalyst fallback zone 23. The separated treated water enters the raw water circulation outlet 9 to become forced circulating raw water.

[0068] S5. The treated water that meets the standards flows out through the raw water outlet 13.

[0069] In the method of this embodiment, the catalyst used is the ozone catalyst provided in the patent application CN114471585A entitled "An ozone catalyst with acetate as a precursor and its preparation method and application", and the catalyst spherical particle size is 3-6 mm.

[0070] In S4, the exhaust gas after gas-water separation is treated by the mist eliminator 14 and discharged through the exhaust gas outlet 15, and then enters the aeration pipe 4 for recycling. Compared with not setting a forced circulation process for raw water, it can increase the residence time of raw water in the catalytic oxidation reaction tower 1 by 30-60 minutes, and maintain the suspended state of catalyst 3 in the suspended vertical flow reaction pipe 2.

[0071] In S3, the steam-water mixture, under the action of the guide plate 24 in the catalytic zone 22, increases its residence time in the vertical flow reaction tube 2, and undergoes a mass transfer process with the catalyst 3.

[0072] In S5, the treatment is deemed to meet the standards by detecting the COD value, and the treated water that meets the standards is discharged through the raw water outlet 13.

[0073] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A catalytic oxidation device for conditioning and pretreatment of coking wastewater, characterized in that, include: A catalytic oxidation reaction tower, which is equipped with a vertical flow reaction tube; The vertical flow reaction tube includes a gas distribution zone, a catalytic zone, and a catalyst fall-off zone connected sequentially from bottom to top. The diameter of the gas distribution zone is larger than the diameter of the catalytic zone, and the diameter of the catalyst fall-off zone is larger than the diameter of the catalytic zone. Within the catalytic zone, the catalyst moves up and down reciprocally. Within the catalyst fall-off zone, the upward-floating catalyst falls back into the catalytic zone. A catalyst feed pipe is provided within the catalyst fall-off zone, and the catalyst feed pipe is connected to the catalyst inlet outside the catalytic oxidation reaction tower. An aeration pipe is installed in the gas distribution zone, and the aeration pipe is connected to an ozone generator outside the catalytic oxidation reaction tower; a water distribution pipe is installed below the gas distribution zone, and the water distribution pipe is connected to a raw water conveying device outside the catalytic oxidation reaction tower. A raw water circulation inlet is provided below the gas distribution zone, and a raw water circulation outlet is provided above the catalyst fall-off zone. The raw water circulation inlet and the raw water circulation outlet are connected by a forced circulation pump. A raw water outlet is provided above the raw water circulation outlet for discharging wastewater that has undergone catalytic oxidation. A mist eliminator is installed above the raw water outlet, and a tail gas outlet is installed above the mist eliminator. The tail gas outlet is connected to the aeration pipe from the outside of the catalytic oxidation reaction tower. A gas flow meter is installed between the ozone generator and the aeration pipe; The exhaust gas outlet is connected to a gas conveying fan, and the gas conveying fan is connected to the inlet of the gas flow meter; The raw water outlet has multiple outlets at different heights; The inner wall of the catalytic zone of the vertical flow reaction tube is connected to an upwardly inclined guide plate, with guide plates of different heights arranged alternately.

2. The coking wastewater conditioning and pretreatment catalytic oxidation device according to claim 1, characterized in that, The catalytic oxidation reaction tower is equipped with multiple vertical flow reaction tubes, all of which are at the same height. The vertical flow reaction tube is separated from the inner surface of the catalytic oxidation reaction tower by a set distance, and is connected to the inner surface of the catalytic oxidation reaction tower by a support frame, so that the vertical flow reaction tube is in a suspended state.

3. The coking wastewater conditioning and pretreatment catalytic oxidation device according to claim 1, characterized in that, A backwash water pipe is installed above the gas distribution zone of the vertical flow reaction tube, and the backwash water pipe is connected to the backwash water inlet outside the catalytic oxidation reaction tower; a backwash water outlet is installed between the raw water outlet and the mist eliminator, and the backwash water inlet and the backwash water outlet are connected to the backwashing device.

4. A method for catalytic oxidation of coking wastewater using the coking wastewater conditioning and pretreatment catalytic oxidation device according to any one of claims 1-3, characterized in that, The process includes the following: S1. Untreated coking wastewater is introduced into the water distribution pipe and mixed with the forced circulating raw water introduced into the raw water circulation inlet to form mixed raw water, which flows upward into the vertical flow reaction pipe. S2. The mixed raw water mixes with the ozone gas input through the aeration pipe in the aeration zone to form a gas-water mixture, which flows upward into the catalytic zone. S3. The carbonated beverage mixture comes into contact with the catalyst moving up and down in the catalytic zone and undergoes an ozone catalytic reaction. S4. The gas-water mixture undergoes gas-water separation in the catalyst fall-off zone, and the separated treated water enters the raw water circulation outlet to become forced circulating raw water. S5. The treated water that meets the standards flows out through the raw water outlet; A raw water outlet is provided above the raw water circulation outlet for discharging wastewater that has undergone catalytic oxidation. A mist eliminator is installed above the raw water outlet, and a tail gas outlet is installed above the mist eliminator. The tail gas outlet is connected to the aeration pipe from the outside of the catalytic oxidation reaction tower. A gas flow meter is installed between the ozone generator and the aeration pipe; The exhaust gas outlet is connected to a gas conveying fan, and the gas conveying fan is connected to the inlet of the gas flow meter; There are multiple raw water outlets at different heights.

5. The catalytic oxidation method for conditioning and pretreatment of coking wastewater according to claim 4, characterized in that, In S4, the exhaust gas after gas-water separation is treated by a mist eliminator and then discharged through the exhaust gas outlet before entering the aeration pipe for recycling.

6. The catalytic oxidation method for conditioning and pretreatment of coking wastewater according to claim 4, characterized in that, In S5, COD is detected to determine whether the treatment meets the standards. If the treatment meets the standards, the raw water outlet is opened.

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