Zero-direct-discharge treatment device for sewage and wastewater of urban rail transit station

Abstract

The utility model discloses a zero direct discharge treatment device for sewage and wastewater of an urban rail transit station, which comprises a regulating reservoir connected with a station sewage and wastewater pipe and used for regulating the water quality and the water quantity of the station sewage and wastewater and conveying the regulated station sewage and wastewater to circulating biochemical treatment equipment; the circulating biochemical treatment equipment is arranged at the downstream of the adjusting tank and is used for carrying out nitrogen and phosphorus removal and impurity removal treatment on the sewage conveyed by the adjusting tank and respectively conveying the treated sewage and sludge to a clean water tank and a sludge storage tank; the clean water tank is arranged at the downstream of the circulating biochemical treatment equipment and is connected with a recycling pipe network system and a municipal rainwater drainage pipe network system through a reclaimed water recycling device; and the sludge storage tank is connected with the circulating biochemical treatment equipment and the regulating tank. The sewage treatment device has the beneficial effects that the sewage treatment efficiency is improved, and the sewage treatment rate reaches more than 95%; the treated water body is stable in performance, and the water resource utilization efficiency is high.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment, and in particular to a zero-direct-discharge treatment device for wastewater from urban rail transit stations. Background Technology

[0002] Urban rail transit stations are the management centers for parking, inspection, maintenance, operation, and repair of subway vehicles. With the rapid development of the economy and urbanization, as of December 31, 2022, 55 cities in mainland my country had put into operation urban rail transit lines exceeding 10,000 kilometers, with a total mileage of 10,291.95 kilometers. As the radiation range of rail transit expands, there is a lack of supporting municipal sewage pipe networks around stations located in suburban areas. The wastewater generated by urban rail transit stations mainly falls into the following categories: (1) Domestic sewage: mainly from the fecal sewage and flushing sewage generated by station staff and passengers using toilets. (2) Industrial wastewater: mainly from the station's daily ground flushing wastewater, air conditioning condensate, air conditioning filter cleaning water, and structural leakage water in underground stations and sections.

[0003] The aforementioned station wastewater must meet national and local wastewater discharge standards and is generally not allowed to be directly discharged into the municipal stormwater drainage system. Currently, the conventional approach is to use a temporary storage + periodic pumping scheme for daily sewage and wastewater from stations, while ensuring the normal operation of rail transit. This scheme has drawbacks such as large storage area required for water tanks, high construction and maintenance costs, waste of land resources, and environmental unfriendliness. Some researchers have attempted to improve upon these issues, such as the Chinese patent for a subway domestic sewage MBR biochemical treatment device (patent number CN 216236557U). This device uses a wastewater transfer pump to lift sewage to an anaerobic tank, where it undergoes denitrification before being sent to an MBR membrane tank. Solid-liquid separation occurs on the MBR biofilm, and the solid sludge settles at the bottom of the MBR tank before entering a sludge nitrification tank. Part of the sludge from the nitrification tank is returned to the anaerobic tank to provide nitrates and nitrites for the anoxic zone, achieving denitrification. The remaining sludge is discharged for further treatment, combining anaerobic treatment with MBR membrane tanks and chemical phosphorus removal. However, this device has a limited actual sewage treatment capacity, and the effluent indicators often fail to meet expectations, making it impossible to truly achieve zero direct discharge. Furthermore, the treated effluent is directly discharged into the municipal stormwater drainage system without further utilization, resulting in water waste. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a zero-direct-discharge treatment device for sewage and wastewater from urban rail transit stations, which solves the problem of low treatment efficiency of sewage and wastewater from subway depots, difficulty in achieving the expected results in effluent indicators, and direct discharge of treated effluent into the municipal stormwater pipe network system, resulting in water waste.

[0005] To solve the above problems, the technical solution adopted by this utility model is as follows:

[0006] This utility model provides a zero-direct-discharge treatment device for sewage and wastewater from urban rail transit stations, comprising:

[0007] The regulating tank is connected to the station's sewage and wastewater pipe and is used to regulate the water quality and quantity of the station's sewage and wastewater, and to transport the regulated station sewage and wastewater to the circulating biological treatment equipment.

[0008] The circulating biological treatment equipment is located downstream of the equalization tank and is used to denitrify, remove phosphorus and remove impurities from the sewage transported in the equalization tank. The treated sewage and sludge are then transported to the clear water tank and sludge storage tank, respectively.

[0009] A clear water tank, located downstream of the circulating biological treatment equipment, is connected to the reuse pipeline system and the municipal stormwater pipeline system via a greywater reuse device. It is used to send qualified water treated by the circulating biological treatment equipment into the reuse pipeline system and / or the municipal stormwater pipeline system.

[0010] The sludge storage tank is connected to the circulating biological treatment equipment and the equalization tank. It is used to receive and store the sludge discharged from the circulating biological treatment equipment and to send the supernatant after sludge removal back into the equalization tank.

[0011] As a preferred embodiment of this application, the circulating biochemical treatment equipment includes an anaerobic tank, a multi-stage biochemical reaction unit, a sedimentation tank, a filtration tank, a disinfection tank, and a biofilm reaction tank. Each stage of the biochemical reaction unit includes an anoxic tank and an aerobic tank connected sequentially by pipelines in the direction of sewage flow. The aerobic tank of the previous stage of the biochemical reaction unit is connected to the anoxic tank of the next stage of the biochemical reaction unit via a biofilm reaction tank. The anaerobic tank is connected to the regulating tank and the anoxic tank of the uppermost stage of the biochemical reaction unit. The sedimentation tank is connected to the aerobic tank and the filtration tank of the lowermost stage of the biochemical reaction unit. The outlet of the filtration tank is connected to the inlet of the disinfection tank, and the disinfection tank is connected to the inlet of the clear water tank.

[0012] As a preferred embodiment of this application, except for the anoxic tank of the uppermost biochemical reaction unit, the anoxic tanks of the other biochemical reaction units are connected to the treated water after it has been treated by the membrane grid through an inlet pipe.

[0013] As a preferred embodiment of this application, the biofilm reactor has a reflux port, which is connected to the aerobic tank of the previous biochemical reaction unit.

[0014] As a preferred embodiment of this application, both the anoxic tank and the aerobic tank are provided with nitrification liquid return ports, and the nitrification liquid return port of the aerobic tank is connected to the nitrification liquid return port of the anoxic tank via a pipeline.

[0015] As a preferred embodiment of this application, it also includes a sludge return pipe assembly, which includes a sludge return pipe and a sludge discharge pipe. The sludge outlet of the sedimentation tank is connected to the sludge return port of the anaerobic tank via the sludge return pipe. The sludge inlet of the sludge storage tank is connected to the sludge discharge port of the equalization tank, the sludge discharge port of the anaerobic tank, the sludge discharge port of the biofilm reactor, the sludge outlet of the sedimentation tank, and the sludge outlet of the filtration tank via the sludge discharge pipe.

[0016] As a preferred embodiment of this application, the reuse pipeline system includes a municipal cleaning pipeline system and an air conditioning water supply pipeline system, both of which are connected to the reuse inlet of the clear water tank.

[0017] As a preferred embodiment of this application, a fine screen is fixedly installed at the inlet of the regulating tank to remove large particles and suspended solids from the station's wastewater.

[0018] As a preferred embodiment of this application, a membrane grid is fixedly installed at the outlet of the regulating tank to remove hair, fibers, and sand and gravel from the sewage and wastewater.

[0019] As a preferred embodiment of this application, the anoxic tank is equipped with a stirring device.

[0020] As a preferred embodiment of this application, the aerobic tank is equipped with aeration equipment.

[0021] Compared with the prior art, the beneficial effects of this utility model are: the treated water has stable performance and meets the water quality standards for reused water in GB / T18920 "Urban Wastewater Reuse for Miscellaneous Use" or the discharge standards for rivers in GB8978 "Integrated Wastewater Discharge Standard"; moreover, the qualified water treated by this application can be reused for road / greening irrigation, toilet flushing, station floor washing, and air conditioning water system replenishment during the air conditioning season, etc. Excess treated water in the non-air conditioning season is discharged into the municipal rainwater pipe network system, which can improve the water resource utilization efficiency of urban rail transit projects, reduce operation and maintenance costs, save energy and reduce carbon emissions, and gradually promote the realization of green, zero-carbon, and smart urban rail transit goals. Attached Figure Description

[0022] Figure 1 This is a structural block diagram of the present invention.

[0023] Figure 2 This is a structural block diagram of the circulating biochemical treatment equipment of this utility model (arrow C represents the water inlet direction; arrow D represents the water outlet direction; arrow E represents the sludge discharge direction).

[0024] Figure 3 This is a connection diagram of the present invention with the reuse pipeline network system and the municipal stormwater pipeline network system (arrow A represents the direction of sludge dewatering and transportation; arrow B represents the direction of screenings transportation).

[0025] The accompanying diagram caption states:

[0026] 1-Equalization tank; 11-Fine screen; 12-Membrane screen; 13-Lift pump;

[0027] 2-Circulating biochemical treatment equipment; 20-Dosing equipment; 21-Anaerobic tank; 22-Anoxic tank; 23-Aerobic tank; 24-Sedimentation tank; 25-Filtration tank; 26-Disinfection tank; 27-Stirring device; 28-Aeration equipment; 29-Nitrification liquor return pipeline; 291-Nitrification liquor return main pipe; 292-Nitrification liquor return branch pipe; 201-First feeding equipment; 202-Second feeding equipment; 203-Biofilm reactor;

[0028] 3-Clear pool;

[0029] 4-Sludge storage tank;

[0030] 5-Reuse pipeline system; 51-Municipal cleaning pipeline system; 52-Air conditioning water supply pipeline system;

[0031] 6-Municipal stormwater drainage system;

[0032] 7-Greywater reuse system;

[0033] 8-Sludge return pipe assembly; 81-Sludge return pipe 81; 82-Sludge discharge pipe;

[0034] 9-Station sewage and wastewater pipes. Detailed Implementation

[0035] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application.

[0036] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0037] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this application does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of implementation of this application. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of this application.

[0038] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0039] In the description of this application, it should be understood that the terms "upper," "lower," "left," "right," "inner," "outer," "axial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0040] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0041] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "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 this application. 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.

[0042] The present application will be further described below with reference to specific embodiments, but the scope of protection of the present application is not limited thereto.

[0043] like Figure 1 As shown, this utility model provides a zero-direct-discharge treatment device for sewage and wastewater from urban rail transit stations, comprising:

[0044] The regulating tank 1 is connected to the station sewage pipe 9 and is used to regulate the water quality and quantity of the station sewage, and to transport the regulated station sewage to the circulating biochemical treatment equipment 2.

[0045] The circulating biological treatment equipment 2 is located downstream of the equalization tank 1 and is used to denitrify, remove phosphorus and remove impurities from the sewage transported by the equalization tank 1, and transport the treated sewage and sludge to the clear water tank 3 and sludge storage tank 4 respectively.

[0046] Clear water tank 3, located downstream of the circulating biological treatment equipment 2, is connected to the reuse pipeline system 5 and the municipal stormwater pipeline system 6 via a greywater reuse device 7. It is used to send qualified water treated by the circulating biological treatment equipment 2 into the reuse pipeline system 5 and / or the municipal stormwater pipeline system 6; and / or

[0047] The sludge storage tank 4 is connected to the circulating biological treatment equipment 2 and the equalization tank 1. It is used to receive and store the sludge discharged by the circulating biological treatment equipment 2, and to send the supernatant after sludge removal back into the equalization tank 1.

[0048] In some embodiments of this utility model, the circulating biochemical treatment equipment 2 includes an anaerobic tank 21, a multi-stage biochemical reaction unit, a sedimentation tank 24, a filtration tank 25, a disinfection tank 26, and a biofilm reaction tank 27. Each stage of the biochemical reaction unit includes an anoxic tank 22 and an aerobic tank 23 connected sequentially by pipelines in the direction of sewage flow. The aerobic tank 23 of the previous stage of the biochemical reaction unit is connected to the anoxic tank 22 of the next stage of the biochemical reaction unit via a biofilm reaction tank. The anaerobic tank 21 is connected to the regulating tank 1 and the anoxic tank 22 of the uppermost biochemical reaction unit. The sedimentation tank 24 is connected to the aerobic tank 23 and the filtration tank 25 of the lowermost biochemical reaction unit. The outlet of the filtration tank 25 is connected to the inlet of the disinfection tank 26, and the disinfection tank 26 is connected to the inlet of the clear water tank 3.

[0049] In some embodiments of this utility model, except for the anoxic tank 22 of the uppermost biochemical reaction unit, the anoxic tanks 22 of the other biochemical reaction units are connected to the treated water after being treated by the membrane grid through the water inlet pipe.

[0050] In some embodiments of this utility model, both the anoxic tank 22 and the aerobic tank 23 are provided with nitrification liquid return ports. The nitrification liquid return port of the aerobic tank 23 is connected to the nitrification liquid return port of the anoxic tank 22 of the same level and the nitrification liquid return port of the anoxic tank 22 upstream through the nitrification liquid return pipeline 29.

[0051] Specifically, the nitrification liquid return pipeline 29 includes a nitrification liquid return main pipe 291 and nitrification liquid return branch pipes 292 connected to the nitrification liquid return main pipe 291. The nitrification liquid return port of the aerobic tank 23 is connected to the nitrification liquid return main pipe 291. Each nitrification liquid return branch pipe 292 is connected to the nitrification liquid return port of the anoxic tank 22 at the same level and the nitrification liquid return port of the anoxic tank 22 upstream, so that the nitrification liquid from each aerobic tank 23 can be collected in the nitrification liquid return main pipe 291 and then sent back to the anoxic tank 22, thereby improving the treatment efficiency.

[0052] In some embodiments of this utility model, the urban rail transit station wastewater zero direct discharge treatment device further includes a sludge return pipe group 8, which includes a sludge return pipe 81 and a sludge discharge pipe 82. The sludge outlet of the sedimentation tank 24 is connected to the sludge return port of the anaerobic tank 21 through the sludge return pipe 81, so that the sludge is returned to the anaerobic tank 21, thereby improving the utilization rate of the sludge. The sludge inlet of the sludge storage tank 4 is connected to the sludge discharge port of the equalization tank 1, the sludge discharge port of the anaerobic tank 21, the sludge discharge port of the biofilm reactor 203, the sludge outlet of the sedimentation tank 24, and the sludge outlet of the filter tank 25 through the sludge discharge pipe 82, so that the remaining sludge of the equalization tank 1, the anaerobic tank 21, the biofilm reactor 203, the sedimentation tank 24, and the filter tank 25 is sent into the sludge storage tank 4.

[0053] In some embodiments of this utility model, an oil separator is also provided between the regulating tank 1 and the station sewage pipe 9.

[0054] In some embodiments of this utility model, the circulating biochemical treatment equipment 2 further includes a dosing device 20 for adding phosphorus removal agents to the uppermost anaerobic tank.

[0055] In some embodiments of this utility model, the circulating biochemical treatment device 2 further includes a first feeding device 201 and a second feeding device 202. The first feeding device 201 is used to add a carbon source to the anoxic tank; the second feeding device 202 is used to add flocculant and / or coagulant to the aerobic tank.

[0056] In some embodiments of this utility model, the reuse pipeline system 5 includes a municipal cleaning pipeline system 51 and an air conditioning water supply pipeline system 52. Both the municipal cleaning pipeline system 51 and the air conditioning water supply pipeline system 52 are connected to the reuse inlet of the clear water tank through the greywater reuse device 7.

[0057] In some embodiments of this utility model, a fine screen 11 is fixedly installed at the inlet of the regulating tank 1 to remove large particles and suspended solids from the station's wastewater. Specifically, the fine screen is a stainless steel fine screen with a pore size of 5mm.

[0058] In some embodiments of this invention, a membrane grid 12 is fixedly installed at the outlet of the regulating tank 1 to remove hair, fibers, and sand from the pipe network in the wastewater. Specifically, the pore size of the membrane grid is 1.5 mm.

[0059] In some embodiments of this utility model, both the anoxic tank 22 and the anaerobic tank 21 are equipped with a stirring device 27.

[0060] In some embodiments of this utility model, the aerobic tank 23 is equipped with an aeration device 28.

[0061] The method for treating wastewater from urban rail transit stations using the zero-direct-discharge treatment device of this utility model includes the following steps:

[0062] Step 1: After collecting the station's sewage water (i.e., raw water), pass it through a stainless steel fine screen with a 5mm aperture through the station's sewage water pipe to remove large particles, suspended solids, and other impurities from the sewage water.

[0063] Step 2: The treated water output from Step 1 is sent to an underground reinforced concrete equalization tank, where it is retained for 24 hours. The pH is adjusted using 0.01 mol / L acid or alkali to regulate the water quality and quantity.

[0064] Step 3: The treated water from Step 2 is lifted by the booster pump 13 and passed through a membrane screen with an aperture of 1.5mm to remove hair, fibers and fine sand and gravel from the pipe network in the domestic water.

[0065] Step 4: The treated water from step 3 is fed into an anaerobic tank for acidification and hydrolysis. The anaerobic tank is equipped with a stirring device to mix the solid and liquid components and prevent sludge from settling.

[0066] Step 5: The treated water from Step 4 is fed into the biochemical reaction unit connected to the anaerobic tank. The treated water passes sequentially through the anoxic tank and the aerobic tank of this stage of the biochemical reaction unit. The anoxic tank of this stage of the biochemical reaction unit is equipped with a stirring device to mix the solid and liquid, and phosphorus removal agent is added to achieve deep phosphorus removal. The aerobic tank is equipped with aeration equipment, and the aeration head of the aeration equipment is aerated and mixed by a blower.

[0067] Step 6: Pass the treated water from Step 5 into the biofilm reactor. The biofilm reactor uses MBR or MBBR membranes, which have a good MLSS retention effect and enhance the oxidative degradation of organic matter.

[0068] Step 7: The treated water from Step 6 is fed into the next stage of the biochemical reaction unit. The treated water passes sequentially through the anoxic tank and the aerobic tank of this stage of the biochemical reaction unit. The anoxic tank of this stage of the biochemical reaction unit is equipped with a stirring device to mix the solid and liquid. This step can use a multi-point water inlet method or add glucose as a carbon source through the first feeding device 201 for microbial growth and metabolism, providing an additional carbon source for nitrogen and phosphorus removal. The aerobic tank is also equipped with an aeration device. PAC and PAM coagulation / flocculation agents are added to the aerobic tank of this stage through the second feeding device 202 to further purify the water. The coagulant is one or more of polyaluminum chloride, polyaluminum sulfate, polyferric chloride, and polyferric sulfate; the flocculant is polyacrylamide.

[0069] Step 8: Pass the treated water from Step 7 into a sedimentation tank to remove larger particles by sedimentation.

[0070] Step 9: Pass the treated water from Step 8 into the filter tank. The quartz stone and activated carbon filter media in the filter tank adsorb and remove impurities in the water and reduce turbidity.

[0071] Step 10: Pass the treated water from step 9 into the disinfection tank. The disinfection tank can be disinfected and sterilized using one or more of the following: disinfectant, bactericidal agent, and ultraviolet lamp. In this embodiment, slow-release chlorine tablets are used for disinfection.

[0072] Step 11: Pass the treated water from Step 10 into the clear water tank and retain it for 2 days; the treated water quality meets the water quality standards for reused urban wastewater in the "Water Quality Standards for Reclaimed Urban Miscellaneous Water Use" (GB / T 18920-2020).

[0073] Step 12: The recycled water from Step 11 is divided into two paths through the recycling pipeline system. One path is connected to the municipal cleaning pipeline system for watering the station's green roads, washing the station floor, flushing toilets, etc.; the other path is connected to the air conditioning water replenishment pipeline system for replenishing the air conditioning water system during the air conditioning season. The excess treated water during the non-air conditioning season overflows into the municipal rainwater pipeline system.

[0074] Step 13: Collect the water used in Step 12 along with other wastewater from the station and return it to Step 1 for further treatment and recycling;

[0075] Step 14: The screenings produced in Steps 1 and 3 shall be collected and transported off-site for processing by a professional unit;

[0076] Step 15: Recycle the mixed liquor from the biofilm reactor to the aerobic tank of the next-stage biochemical reaction unit at a recycling rate of 100%.

[0077] Step 16: Recycle the mixed liquor from the aerobic tank to the anoxic zone of the same and previous biochemical reaction units at a recycling ratio of 300-400%.

[0078] Step 17: Return the sludge from the sedimentation tank to the anaerobic zone at a return ratio of 30% to 100%.

[0079] Step 18: Discharge the remaining sludge from the anaerobic tank, biofilm reactor, sedimentation tank, and filtration tank into the sludge storage tank; the sludge in the sludge storage tank is dewatered by a screw press and then collected and transported off-site for treatment by a professional unit.

[0080] Step 19: Return the supernatant in the sludge storage tank to the equalization tank.

[0081] Through the above-mentioned deep treatment, the effluent quality meets the requirements of the "Urban Wastewater Reuse for Urban Miscellaneous Use" standard (GB / T18920-2020). It can not only be reused for greening irrigation, car washing, road cleaning, toilet flushing, etc., but also be supplied to the air conditioning water system for replenishment during the air conditioning season. During the non-air conditioning season, it overflows into the municipal rainwater pipe network system. The sewage generated by the municipal cleaning pipe network system is sent back to this zero direct discharge treatment device for re-treatment, achieving the goal of true "zero direct discharge".

[0082] The above embodiments are for illustrating the implementation schemes disclosed in this utility model and should not be construed as limiting the utility model. Furthermore, various modifications listed herein, as well as variations in the methods and compositions of the utility model, will be apparent to those skilled in the art without departing from the scope and spirit of this utility model. Although this utility model has been specifically described in conjunction with various specific preferred embodiments, it should be understood that this utility model should not be limited to these specific embodiments. In fact, various modifications as described above that are obvious to those skilled in the art to obtain the utility model should be included within the scope of this utility model.

Claims

1. A zero-direct-discharge treatment device for sewage and wastewater from urban rail transit stations, characterized in that, include: The regulating tank (1) is connected to the station sewage pipe (9) and is used to regulate the water quality and quantity of the station sewage, and to transport the regulated station sewage to the circulating biochemical treatment equipment (2). A circulating biochemical treatment device (2) is set downstream of the regulating tank (1) to treat the sewage transported by the regulating tank (1) for denitrification, phosphorus removal and impurity removal, and to transport the treated sewage and sludge to the clear water tank (3) and sludge storage tank (4) respectively; the clear water tank (3) is set downstream of the circulating biochemical treatment device (2), and the clear water tank (3) is connected to the reuse pipeline system (5) and the municipal rainwater pipeline system (6) through the greywater reuse device (7), and is used to send the qualified water body treated by the circulating biochemical treatment device (2) into the reuse pipeline system (5) and / or the municipal rainwater pipeline system (6); as well as The sludge storage tank (4) is connected to the circulating biological treatment equipment (2) and the equalization tank (1) to receive and store the sludge discharged by the circulating biological treatment equipment (2) and send the supernatant after sludge removal back into the equalization tank (1).

2. The urban rail transit station wastewater zero direct discharge treatment device according to claim 1, characterized in that: The circulating biochemical treatment equipment (2) includes an anaerobic tank (21), a multi-stage biochemical reaction unit, a sedimentation tank (24), a filter tank (25), a disinfection tank (26), and a biofilm reaction tank (203). Each stage of the biochemical reaction unit includes an anoxic tank (22) and an aerobic tank (23) connected sequentially by pipelines in the direction of sewage flow. The aerobic tank (23) of the previous stage of the biochemical reaction unit is connected to the anoxic tank (22) of the next stage of the biochemical reaction unit, and the biofilm reaction tank is connected between them. The anaerobic tank (21) is connected to the regulating tank (1) and the anoxic tank (22) of the uppermost biochemical reaction unit. The sedimentation tank (24) is connected to the aerobic tank (23) and the filter tank (25) of the lowermost biochemical reaction unit. The outlet of the filter tank (25) is connected to the inlet of the disinfection tank (26). The disinfection tank (26) is connected to the inlet of the clear water tank (3).

3. The urban rail transit station wastewater zero direct discharge treatment device according to claim 2, characterized in that: Except for the anoxic tank (22) of the top-level biochemical reaction unit, the anoxic tanks (22) of the other biochemical reaction units are connected to the treated water after being treated by the membrane grid through the water inlet pipe.

4. The urban rail transit station wastewater zero direct discharge treatment device according to claim 2, characterized in that: Both the anoxic tank (22) and the aerobic tank (23) are equipped with nitrification liquid return ports. The nitrification liquid return port of the aerobic tank (23) is connected to the nitrification liquid return port of the anoxic tank (22) of the same level and the nitrification liquid return port of the anoxic tank (22) upstream through the nitrification liquid return pipeline (29).

5. The urban rail transit station wastewater zero-direct-discharge treatment device according to claim 2, characterized in that: It also includes a sludge return pipe assembly (8), which includes a sludge return pipe and a sludge discharge pipe. The sludge outlet of the sedimentation tank (24) is connected to the sludge return port of the anaerobic tank (21) through the sludge return pipe. The sludge inlet of the sludge storage tank (4) is connected to the sludge discharge port of the regulating tank (1), the sludge discharge port of the anaerobic tank (21), the sludge discharge port of the biofilm reactor, the sludge outlet of the sedimentation tank (24), and the sludge outlet of the filter tank (25) through the sludge discharge pipe.

6. The urban rail transit station wastewater zero direct discharge treatment device according to claim 1, characterized in that: The reuse pipeline system (5) includes a municipal cleaning pipeline system (51) and an air conditioning water supply pipeline system (52). Both the municipal cleaning pipeline system (51) and the air conditioning water supply pipeline system (52) are connected to the reuse inlet of the clear water tank.

7. The urban rail transit station wastewater zero direct discharge treatment device according to claim 1, characterized in that: A fine screen (11) is fixedly installed at the inlet of the regulating tank (1) to remove large particles and suspended solids from the station's wastewater.

8. The urban rail transit station wastewater zero direct discharge treatment device according to claim 1, characterized in that: A membrane grid (12) is fixedly installed at the outlet of the regulating tank (1) to remove hair, fibers and sand from the pipe network in the wastewater.

9. The urban rail transit station wastewater zero direct discharge treatment device according to claim 2, characterized in that: The circulating biochemical treatment equipment (2) also includes a dosing device (20).

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