Apparatus suitable for advanced treatment of sewage biochemical tailwater and its use

Abstract

To provide an apparatus suitable for advanced treatment of sewage biochemical process tail water and a method for its use.SOLUTION: An apparatus suitable for advanced treatment of sewage biochemical process tail water and a method of use thereof, including a photocatalytic oxidation advanced treatment unit, a discharge water pond, and two sets of parallel alternately operated artificial wetland systems of the same configuration, the parallel alternately operated artificial wetland systems including a hypoxic subsurface flow artificial wetland unit, an aerobically aerated artificial wetland unit, and a dry-wet alternating tidal artificial wetland unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus suitable for advanced treatment of tailwater in a sewage biochemical process and a method for using the same, and belongs to the field of water treatment equipment. [Background technology]

[0002] Constructed wetlands, a sewage biological treatment technology developed in the late 1970s, are engineered systems composed of aquatic plants, substrates, and microorganisms that purify sewage using natural processes. Constructed wetlands are a commonly used sewage treatment process. Constructed wetlands are integrated ecosystems that utilize the principles of symbiosis among biological species and the regeneration of material cycles, as well as the principles of structure and function coordination, to promote the efficient circulation of pollutants in wastewater, fully unleash the resource's production potential, prevent environmental recontamination, and maximize the effectiveness and benefits of sewage treatment and resource utilization. Constructed wetland plants can also transport oxygen to water bodies, increasing their vitality. Wetland plants have also played an important role in controlling water pollution and decomposing harmful substances. Microorganisms in wetland systems are the primary force responsible for decomposing pollutants in water bodies. Aerobic microorganisms respire to break down most of the organic matter in wastewater into carbon dioxide and water; anaerobic bacteria break down organic matter into carbon dioxide and methane; nitrifying bacteria nitrify ammonium salts; and denitrifying bacteria reduce nitrate nitrogen to nitrogen gas. Through this process, the major organic pollutants in sewage are decomposed and assimilated, becoming part of microbial cells; the remainder is converted into inorganic substances harmless to the environment and returned to nature. Wetland ecosystems are also home to some protozoans and metazoans, and even some wetland insects and birds participate in ingesting and assimilating the organic particles deposited in the wetland system, absorbing them as nutrients, and to a certain extent, eliminating particulate matter in sewage.

[0003] Patent Document 1 uses a differentiated filling method, with a base substrate in the bottom layer and a microorganism-supported modular substrate in the top layer. A level regulator is attached to the end of the drainage pipe connected to the collection pipe, allowing for flexible adjustment of the system's water level, achieving functions such as water volume regulation and wetland backwash. However, this method is disadvantageous to the long-term stable operation of the system. Patent Document 2 divides a conventional constructed wetland system into multiple parallel-arranged constructed wetland subunits, each of which can control the inflow volume from the distribution channel. This allows each constructed wetland unit to operate independently, achieving the goals of not interfering with each other when adding or replacing plants and microorganisms, and avoiding production cuts and interruptions. This enhances the long-term operational stability of the constructed wetland system and strengthens the system's ability to handle localized maintenance. However, this method does not reduce the impact of biological residual decay on the effluent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Chinese patent with publication number CN217148732U [Patent Document 2] Chinese patent with publication number CN217323562U Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION The present invention aims to provide an apparatus suitable for advanced treatment of sewage biochemical tailwater and a method for using the same, in order to overcome the drawbacks and deficiencies of the prior art. [Means for solving the problem]

[0006] This device is suitable for advanced treatment of tailwater through a sewage biochemical process, and includes a photocatalytic oxidation advanced treatment unit, an effluent pond, and two sets of parallel, alternating-operation constructed wetland systems with the same configuration, each of which includes a low-oxygen subsurface flow constructed wetland unit, an aerobic aeration constructed wetland unit, and a wet-dry alternating tidal constructed wetland unit.

[0007] Furthermore, the volume ratio of the photocatalytic oxidation advanced treatment unit, the discharge pond, the low-oxygen underground flow type constructed wetland unit, the aerobic aeration type constructed wetland unit, and the wet-dry alternating tidal type constructed wetland unit is 1:0.1 to 0.3:1:1:1.

[0008] Preferably, a photocatalytic reaction baffle is installed in the photocatalytic oxidation advanced treatment unit, the inside of the photocatalytic reaction baffle is hollow, a lighting device is installed in the photocatalytic reaction baffle, a photocatalytic material having a thickness of 0.5 to 10 mm is supported on the surface of the photocatalytic reaction baffle, the light emitted from the lighting device is visible light or ultraviolet light, and the photocatalytic material Fee Titanium dioxide, carbon nitride, zinc oxide and tin oxide One or more selected from Photocatalytic materials For a fee be.

[0009] Furthermore, the low-oxygen underground flow constructed wetland units, aerobic aeration constructed wetland units, and wet-dry alternating tidal constructed wetland units all had false bottoms installed at the bottom, which were 10 cm away from the bottom of each wetland unit. A sludge outlet and sludge pump were installed at the bottom of each wetland unit, and the false bottoms were made of stainless steel with a thickness of 5 to 25 mm, an opening size of 5 to 15 mm, and an opening rate of 10%.

[0010] Preferably, an aeration head is installed in the bottom space of the false bottom of the aerobic aeration type constructed wetland unit, and a blower is connected to the aeration head to supply gas according to a gas-water ratio of 2 to 10:1.

[0011] In addition, between different wetland units, a side T-shaped water pipe is installed to connect the photocatalytic oxidation advanced treatment unit and the wetland unit, or the two wetland units before and after. The side openings of the side T-shaped water pipe and the openings of the upper and lower pipes are blocked by a lattice-shaped permeable plug, and the bottom of the T-shaped water pipe is blocked by the bottom of the false bottom. Each wetland unit Bottom 5 in It penetrates up to cm.

[0012] Preferably, in the low-oxygen subsurface flow constructed wetland unit, biomass carbon, iron scrap, etc. are used in a volume ratio of 10 to 50%. and pyrite One or more selected from Reinforced filler - The aerobic aeration type constructed wetland unit and the wet-dry alternating tidal wetland unit are mixed with ordinary gravel filler, the particle size of which is 5-10cm. In the aerobic aeration type constructed wetland unit and the wet-dry alternating tidal wetland unit, zeolite is used in an amount of 10-50% by volume. and volcanic rock One or more selected from Reinforced filler - It is placed and mixed with ordinary gravel filler, the particle size of the filler is 3-5cm.

[0013] Preferably, in the wet-dry alternating tidal artificial wetland unit, a liquid level sensor and a drainage pump are installed, and the liquid level sensor has a permeable hole. Exclusion placed in the water pipe, The liquid level sensor includes an upper liquid level sensor and a lower liquid level sensor, Top liquid level The distance between the sensor and the top pipe opening is 5 to 10 cm. liquid level The distance between the sensor and the bottom of the pipe is 5 to 10 cm. The aforementioned The diameter of the drainage pipe is 5 to 15 cm, and permeable holes are uniformly distributed on both sides of the drainage pipe, the diameter of the permeable holes is 0.5 to 1 cm, and the interval between adjacent permeable holes is 20 cm.

[0014] Preferably, a water supply solenoid valve is installed at the water inlet point of the aerobic aeration type constructed wetland unit, and the lighting fixtures in the photocatalytic reaction baffle, the liquid level sensor and drainage pump in the wet-dry alternating tidal type constructed wetland unit, the water supply solenoid valve and the blower are all uniformly controlled by the central control system.

[0015] The present invention further provides a method for using the device suitable for advanced treatment of tailwater from a sewage biochemical process, which involves using the device suitable for advanced treatment of tailwater from a sewage biochemical process to treat the tailwater. First, the tailwater from a sewage biochemical process enters the reaction tank of the photocatalytic oxidation advanced treatment unit from the water supply pipe, mixes with the reflux effluent, and then flows through the photocatalytic reaction baffle in a baffle manner, and the chemical residues in the tailwater are removed through photocatalytic oxidation. Things After removal, the wastewater is controlled via the water supply solenoid valve and enters one constructed wetland system. It is sequentially treated through a hypoxic subsurface flow constructed wetland unit, an aerobic aeration constructed wetland unit, and a wet-dry alternating tidal constructed wetland unit to achieve denitrification. After further removal of ammonia nitrogen, phosphorus, and residual organic matter, the liquid level in the wet-dry alternating tidal constructed wetland unit reaches the upper liquid level sensor. At the same time, the water supply solenoid valve of that wetland system is turned off and the drainage pump of that wet-dry alternating tidal wetland unit is turned on. Some of the wastewater enters the effluent tank and settles there before being used as an effluent discharge device, while the other part flows back to the reaction tank of the photocatalytic oxidation advanced treatment unit and discharges to the lower liquid level sensor. The drainage pump is then turned off and the wetland system enters standby mode. The drainage pump is turned on while the water supply solenoid valve of the other wetland system is turned on, and the same operating flow is initiated to achieve alternating operation.

[0016] The low-oxygen subsurface flow constructed wetland unit and the aerobic aerated constructed wetland unit control the water flow via an overflow plate numbered 1. The aerobic aerated constructed wetland unit and the wet-dry alternating tidal constructed wetland unit control the water flow via an overflow plate numbered 2. The wet-dry alternating tidal constructed wetland unit and the tailwater advanced treatment unit control the water flow via a submersible pump. [Effects of the Invention]

[0017] The beneficial effects of the present invention are as follows. Using the above technical solution, the technical effects of the present invention are as follows: 1. By using two sets of constructed wetland groundwater treatment systems, the sewage treatment performance of each set of systems can be effectively utilized to maintain efficient water treatment performance at all times. 2. The system is divided into various wetland units, such as a hypoxic subsurface flow constructed wetland, an aerobic aeration constructed wetland, and a wet-dry alternating tidal constructed wetland. Treating sewage using the specific functions of each wetland unit improves the high-load resistance capacity, sewage treatment capacity, and stability of the constructed wetland system. 3. The wet-dry alternating tidal constructed wetland improves denitrification and phosphorus removal capabilities using the wet-dry alternating method, effectively preventing biological residue decay in the wetland from affecting the effluent, ensuring the stability of the effluent water quality. 4. The photocatalytic oxidation advanced treatment unit performs advanced treatment of some resistant organic matter in the tailwater and simultaneously sterilizes it to ensure the safety of the effluent. [Brief explanation of the drawings]

[0018] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the drawings that need to be used in the description of the embodiments or prior art will be briefly described below. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings obtained based on these drawings still belong to the scope of the present invention, under the premise that no creative labor is paid.

[0019] [Figure 1] FIG. 1 is a schematic plan view of a specific example of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of FIG. 1. [Figure 3] 1 is a schematic diagram of a photocatalytic oxidation advanced treatment unit in a specific embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will now be described in more detail with reference to the drawings.

[0021] It should be noted that all the expressions of "first" and "second" in the embodiments of the present invention are for distinguishing between two entities with the same name but not the same entity or not the same parameter, and it is understood that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention, and the subsequent embodiments will not describe them one by one.

[0022] The direction and position terms referred to in the present invention, such as "upper", "lower", "front", "rear", "left", "right", "inner", "outer", "top", "bottom", "side", etc., are only directions or positions referring to the drawings, and therefore the direction and position terms used are used to explain and understand the present invention, rather than as limitations on the protection scope of the present invention.

[0023] As shown in Figures 1 to 3, this is an example of an apparatus suitable for advanced treatment of sewage tailwater through a biochemical process, and a method for using the same. The apparatus includes a photocatalytic oxidation advanced treatment unit 2, an effluent pond 9, and two sets of parallel alternating-operation constructed wetland systems with the same configuration. The parallel alternating-operation constructed wetland systems include a low-oxygen subsurface flow constructed wetland unit 3, an aerobic aeration constructed wetland unit 4, and a wet-dry alternating tidal constructed wetland unit 5.

[0024] The volume ratio of the photocatalytic oxidation advanced treatment unit 2, the discharge pond 9, the low-oxygen underground flow type constructed wetland unit 3, the aerobic aeration type constructed wetland unit 4, and the wet-dry alternating tidal type constructed wetland unit 5 is 1:0.1 to 0.3:1:1:1, and the specific volume ratio can be flexibly adjusted according to the actual installation environment.

[0025] A photocatalytic reaction baffle 8 is installed within the photocatalytic oxidation advanced treatment unit 2, the interior of the photocatalytic reaction baffle 8 is hollow, and a lighting fixture is installed within the photocatalytic reaction baffle 8, and a photocatalytic material with a thickness of 0.5 to 10 mm is supported on the surface of the photocatalytic reaction baffle 8. The light emitted by the lighting fixture is visible light or ultraviolet light, and the photocatalytic material is one or more of titanium dioxide, carbon nitride, zinc oxide, tin oxide, etc., which is used to carry out a photocatalytic reaction on the inflowing water. The shape of the lighting fixture is selected to be flat so that it can irradiate the inflowing water with the maximum area and improve the reaction speed, and the intensity of the emitted light must also be adjusted to an intensity that can generate a reaction.

[0026] A false bottom 11 is installed at the bottom of each of the low-oxygen underground flow constructed wetland units 3, aerobic aeration constructed wetland units 4, and wet-dry alternating tidal constructed wetland units 5. The false bottoms 11 are 10 cm away from the bottom of each wetland unit, and a sludge outlet and sludge pump 20 are installed at the bottom of each wetland unit. The false bottoms 11 are made of stainless steel with a thickness of 5 to 25 mm, an opening size of 5 to 15 mm, and an opening rate of 10%.

[0027] An aeration head 12 is installed in the bottom space of the false bottom 11 of the aerobic aeration type constructed wetland unit 4, and a blower is connected to the aeration head 12 to supply gas according to a gas-water ratio of 2 to 10:1.

[0028] Between different wetland units, a side T-shaped water pipe 13 is installed to connect the photocatalytic oxidation advanced treatment unit 2 and the wetland unit, or to connect two wetland units before and after. The side openings of the side T-shaped water pipe 13 and the openings of the upper and lower pipes are blocked by lattice-shaped permeable plugs, and the bottom of the T-shaped water pipe 13 is connected to the bottom of the false bottom 11. Each wetland unit It penetrates to the bottom about 5cm.

[0029] In the low-oxygen underground flow constructed wetland unit 3, one or more types of reinforcing fillers 18 such as biomass carbon, iron scrap, pyrite, etc. are placed at a volume ratio of 10 to 50% and mixed with ordinary gravel filler 18, the particle size of the filler 18 being 5 to 10 cm. In the aerobic aeration constructed wetland unit 4 and the wet-dry alternating tidal wetland unit, one or more types of reinforcing fillers 18 such as zeolite, volcanic rock, etc. are placed at a volume ratio of 10 to 50% and mixed with ordinary gravel filler 18, the particle size of the filler 18 being 3 to 5 cm.

[0030] In the wet-dry alternating tidal artificial wetland unit 5, a liquid level sensor and a drainage pump 14 are installed, and the liquid level sensor has a permeable hole. Exclusion placed in the water pipe, The liquid level sensor includes an upper liquid level sensor 15 and a lower liquid level sensor 19. Top liquid level The distance between the sensor and the top pipe opening is 5 to 10 cm. liquid level The distance between the sensor and the bottom of the pipe is 5 to 10 cm, the diameter of the drainage pipe is 5 to 15 cm, permeable holes are uniformly distributed on both sides of the drainage pipe, the diameter of the permeable holes is 0.5 to 1 cm, and the spacing between adjacent permeable holes is 20 cm.

[0031] A water supply solenoid valve 7 is installed at the inflow point of the aerobic aeration type constructed wetland unit 4, and the lighting fixtures in the photocatalytic reaction baffle 8, the liquid level sensor and drainage pump 14 in the dry-wet alternating tidal type constructed wetland unit 5, the water supply solenoid valve 7 and the blower are all uniformly controlled by the central control system.

[0032] This device can be flexibly applied to the treatment of small volumes of sewage, such as that of single-family or rural residents with several families, and can effectively buffer the shock load caused by small volumes of uneven pulsed discharge. At the same time, the combination of a multi-type constructed wetland system with a photocatalytic oxidation device can produce high-quality effluent. At the same time, the installation of a sludge pump 20 and a false bottom 11 can achieve regular sludge discharge, solving the problem of constructed wetlands being prone to blockage.

[0033] The present invention further provides a method for using the device suitable for advanced treatment of tailwater from a sewage biochemical process. The device is used to treat tailwater from a sewage biochemical process. The device is configured to have a water inlet (1) in a photocatalytic oxidation advanced treatment unit (2). The photocatalytic oxidation advanced treatment unit (2) and the low-oxygen subsurface flow constructed wetland unit (3) are connected via a water supply solenoid valve (7) to control the water flow. The effluent from the constructed wetland is then circulated back to the photocatalytic oxidation advanced treatment unit (2) via a PV pipe (6) numbered 1. The water in the photocatalytic oxidation advanced treatment unit (2) is a mixture of influent and return water, which flows through a photocatalytic reaction baffle (8) in a baffle-like manner. The photocatalytic reaction baffle (8) is loaded with a photocatalytic material and has a lighting fixture installed inside. Through photocatalytic oxidation, organic matter that is difficult to decompose, such as chemical residues, in the water is removed. The photocatalytically oxidized tailwater is then circulated through the water supply solenoid valve (7). The wastewater enters a set of constructed wetlands, passing through the hypoxic subsurface flow constructed wetland unit 3, the aerobic aeration constructed wetland unit 4, and the wet-dry alternating tidal constructed wetland unit 5 for treatment. T-shaped water pipes 13 are installed between the different wetland units to achieve denitrification and further remove ammonia nitrogen, phosphorus, and residual organic matter. When the liquid level in the wet-dry alternating tidal constructed wetland unit 5 reaches the upper liquid level sensor, the water supply solenoid valve 7 of the wetland system is turned off and the drainage pump 14 of the wet-dry alternating tidal wetland unit 5 is turned on. Some of the wastewater enters the effluent tank 9, where it settles and is used as an effluent discharge device. The remaining part of the wastewater flows back to the reaction tank of the photocatalytic oxidation advanced treatment unit 2 and is discharged to the lower liquid level sensor 19. The drainage pump 14 is then turned off and the wetland system enters standby mode. andAt the same time, the water supply solenoid valve 7 of another set of wetland systems was turned on, starting the same operation flow and enabling alternating operation. In the different wetland units, false bottoms 11 were installed to collect biofilm sludge, and sludge pumps 20 were added to the bottom of the false bottoms 11 to enable sludge removal. Fillers such as biomass carbon, iron filings, and pyrite were added to the low-oxygen subsurface flow constructed wetland unit 3 to promote autotrophic denitrification. Fillers such as zeolite and volcanic rock were added to the aerobic aeration constructed wetland unit 4 and the wet-dry alternating tidal wetland unit 5, and an aeration head 12 was installed in the aerobic aeration constructed wetland unit 4 to promote the removal of organic matter and ammonia nitrogen.

[0034] The wetland system using the above-mentioned device of the present invention has an effluent that meets the first-level B discharge standard specified in the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002), and the operating cost per ton of water is 0.05 yuan / ton, which is much lower than that of general sewage treatment processes. The operation and management are simple, and the number of disease bacteria in the effluent is all below the detection limit and meets the reuse standard.

[0035] The above disclosure is merely a preferred embodiment of the present invention, which of course cannot be limited to the scope of the claims of the present invention, and therefore, equivalent variations based on the claims of the present invention still belong to the scope covered by the present invention.

[0036] While the present invention has been described with reference to several specific embodiments, it is to be understood that the invention is not limited to the specific embodiments disclosed, and the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. [Explanation of symbols]

[0037] 1, inflow water end 2. Photocatalytic oxidation advanced treatment unit 3. Low-oxygen underground flow constructed wetland unit 4. Aerobic aerated constructed wetland unit 5. Alternating wet and dry tidal artificial wetland unit 6. PV tube number 1 7. Water supply solenoid valve 8. Photocatalytic reaction baffle 9. Discharge pond 10, Outflow water end 11, false bottom 12. Aeration head 13, T-type water pipe 14. Drainage pump 15. Upper liquid level sensor 16, 2 number PV tube 17. Soil layer 18. Filler 19. Lower liquid level sensor 20. Sludge pump

Claims

1. The system comprises a photocatalytic oxidation advanced treatment unit, an effluent pond, and two sets of parallel alternating operation constructed wetland systems of the same configuration, the parallel alternating operation constructed wetland systems including a low-oxygen subsurface flow constructed wetland unit, an aerobic aeration constructed wetland unit, and a wet-dry alternating tidal constructed wetland unit; a photocatalytic reaction baffle is installed in the photocatalytic oxidation advanced treatment unit, the inside of the photocatalytic reaction baffle is hollow, a lighting device is installed in the photocatalytic reaction baffle, a photocatalytic material having a thickness of 0.5 to 10 mm is carried on the surface of the photocatalytic reaction baffle, the light emitted by the lighting device is visible light or ultraviolet light, and the photocatalytic material is one or more photocatalytic materials selected from titanium dioxide, carbon nitride, zinc oxide and tin oxide; In the low-oxygen underground flow constructed wetland unit, one or more reinforcing fillers selected from biomass carbon, iron scrap, and pyrite are disposed in a volume ratio of 10-50%, mixed with ordinary gravel filler, and the particle size of the filler is 5-10 cm; in the aerobic aeration constructed wetland unit and the wet-dry alternating tidal wetland unit, one or more reinforcing fillers selected from zeolite and volcanic rock are disposed in a volume ratio of 10-50%, mixed with ordinary gravel filler, and the particle size of the filler is 3-5 cm; In the wet-dry alternating tidal artificial wetland unit, a liquid level sensor and a drainage pump are installed, the liquid level sensor is disposed in a drainage pipe having a permeable hole, the liquid level sensor includes an upper liquid level sensor and a lower liquid level sensor, the distance between the upper liquid level sensor and the top pipe mouth is 5-10 cm, the distance between the lower liquid level sensor and the pipe bottom is 5-10 cm, the diameter of the drainage pipe is 5-15 cm, permeable holes are uniformly distributed on both sides of the drainage pipe, the diameter of the permeable holes is 0.5-1 cm, and the interval between adjacent permeable holes is 20 cm, A water supply solenoid valve is installed at the water inlet point of the aerobic aeration type constructed wetland unit, and the lighting fixtures in the photocatalytic reaction baffle, the liquid level sensor in the wet-dry alternating tidal type constructed wetland unit, the water supply solenoid valve and the fan are all uniformly controlled by a central control system. Each of the two parallel alternating-operation constructed wetland systems is sequentially configured with a low-oxygen subsurface flow constructed wetland unit, an aerobic aeration constructed wetland unit, and a wet-dry alternating tidal constructed wetland unit. A photocatalytic oxidation advanced treatment unit is disposed between two sets of low-oxygen subsurface flow constructed wetland units and aerobic aeration constructed wetland units in two sets of parallel alternating operation constructed wetland systems; A tailwater pond is disposed between two sets of wet-dry alternating tidal constructed wetland units in two sets of parallel alternating-operation constructed wetland systems; The discharge pond is connected to a photocatalytic oxidation advanced treatment unit and two sets of wet-dry alternating tidal constructed wetland units. Between the different wetland units, a side T-shaped water pipe is installed to connect the photocatalytic oxidation advanced treatment unit and the wetland unit, or the two wetland units before and after. The low-oxygen underground flow type constructed wetland units, aerobic aeration type constructed wetland units, and wet-dry alternating tidal type constructed wetland units all have false bottoms at their bottoms, the false bottoms are 10 cm away from the bottom of each wetland unit, and a sludge outlet and sludge pump are installed at the bottom of each wetland unit. The false bottoms are made of stainless steel with a thickness of 5 to 25 mm, an opening size of 5 to 15 mm, and an opening rate of 10%. an aeration head is installed in the bottom space of the false bottom of the aerobic aeration type constructed wetland unit, and a blower is connected to the aeration head to supply gas according to a gas-water ratio of 2 to 10:1; It is used as an effluent discharge device after part of the wastewater from the effluent enters the effluent pond and settles, and is arranged so that the other part of the wastewater from the effluent flows back to the photocatalytic oxidation advanced treatment unit. The present invention relates to an apparatus suitable for advanced treatment of sewage biochemical tailwater.

2. The device suitable for advanced treatment of sewage biochemical tailwater as described in claim 1, characterized in that the volume ratio of the photocatalytic oxidation advanced treatment unit, the discharge pond, the low-oxygen underground flow type constructed wetland unit, the aerobic aeration type constructed wetland unit, and the wet-dry alternating tidal type constructed wetland unit is 1:0.1 to 0.3:1:1:

1.

3. The device suitable for advanced treatment of sewage biochemical tailwater as described in claim 1, characterized in that the side openings of the lateral T-shaped water pipe and the openings of the upper and lower pipes are blocked by lattice-shaped permeable plugs, and the bottom of the T-shaped water pipe extends from the bottom of the false bottom to the bottom of each wetland unit up to 5 cm.

4. The device for advanced treatment of tailwater from sewage biochemical processes according to any one of claims 1 to 3 is used to carry out treatment. First, the tailwater from sewage biochemical processes enters the reaction tank of the photocatalytic oxidation advanced treatment unit from the water supply pipe, mixes with the reflux effluent, and then flows through the photocatalytic reaction baffle in a baffle manner. After the chemical residues in the tailwater are removed through photocatalytic oxidation, the tailwater is controlled by the water supply solenoid valve and enters a set of constructed wetlands. It passes through the low-oxygen subsurface flow constructed wetlands, the aerobic aeration constructed wetlands, and the alternating wet-dry tidal constructed wetlands in sequence to achieve denitrification, and further removes ammonia nitrogen, phosphorus, and residual organic matter. Then, it is transferred to the alternating wet-dry tidal constructed wetlands. When the liquid level in the engineered wetland unit reaches the upper level sensor of the liquid level sensor, the water supply solenoid valve of the wetland system in that set is turned off and the drainage pump of the wet-dry alternating tidal wetland unit in that wetland system is turned on. When part of the wastewater enters the effluent tank and is used as an effluent discharge device after settling, and the other part flows back to the reaction tank of the photocatalytic oxidation advanced treatment unit and discharges to the lower level sensor, the drainage pump is turned off and the wetland system in that set enters a standby state. When the drainage pump is turned on, the water supply solenoid valve of the other wetland system is turned on, and the same operation flow is initiated to achieve alternating work.

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