Seasonal wastewater double circulation treatment system and method

Abstract

A seasonal wastewater double circulation treatment system, a water quantity and water quality regulating tank is set between a sedimentation tank and an aerobic biofilm and activated sludge composite biochemical tank, and the water outlet of the water quantity and water quality regulating tank is connected to the water inlet of the aerobic biofilm and activated sludge composite biochemical tank, and a first reflux device is set between the water quantity and water quality regulating tank and the activated sludge sedimentation recovery tank. In the non-pollutant-producing season, the first reflux device responds to the first opening operation, and all the supernatant in the activated sludge sedimentation recovery tank is transported to the water quantity and water quality regulating tank for circulation treatment, and the precipitate in the first regulating tank is flushed by the reflux water, and the solid carbon source is further converted into a dissolved state to supplement the wastewater carbon source in the non-pollutant-producing season. In the pollution-producing season, the first reflux device responds to the third opening operation, and part of the supernatant in the activated sludge sedimentation recovery tank is transported to the water quantity and water quality regulating tank for circulation treatment. The present application also provides a seasonal wastewater double circulation treatment system method.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a seasonal wastewater double circulation treatment system and method. Background Art

[0002] Industrial wastewater discharge generated by my country's huge industrial scale has attracted increasing public attention as the online continuous monitoring capability of pollution sources has been rapidly improved. Seasonal intermittent wastewater discharge sources formed by raw material limitations, such as agricultural and sideline food processing industries, have also been accelerated to be included in the emission supervision and pollutant discharge permit management system in recent years, and the requirements for stable compliance of seasonal intermittent wastewater with standards have been rapidly increased.

[0003] The eastern foot of the Helan Mountains is located between the alluvial plain of the Yellow River in Ningxia and the alluvial fan of the Helan Mountains. It is backed by the majestic Helan Mountains in the west, the upper reaches of the Yellow River in the east, and the ancient city of Yinchuan in the north. The total area is 200,000 hectares. The eastern foot of the Helan Mountains has sufficient sunshine, with 3,000 hours of sunshine throughout the year. The sandy soil on the Gobi Desert is rich in minerals. The eastern foot of the Helan Mountains is located between 37 and 39 degrees north latitude, which is the best area for growing grapes. The altitude of 1,000 to 1,500 meters is suitable for grape growth. The annual rainfall does not exceed 200 mm. The sunshine, soil, water, altitude and latitude of the eastern foot of the Helan Mountains are all conducive to growing grapes. Therefore, many wineries have been built in the eastern foot of the Helan Mountains. Wastewater is generated during the winemaking process. The wastewater is produced during the harvest and pressing season from September to November each year. The wastewater treatment facilities of the winery only have sufficient wastewater sources in the second half of each year. Similarly, Ningxia Xiji potato starch processing also has the same characteristics, harvesting and processing in the second half of the year, and no production in the first half of the year. The generation of wastewater has typical seasonal characteristics.

[0004] The existing winery and potato starch wastewater biochemical treatment projects have the following technical problems: 1. During the pollution-producing season, the wastewater volume is large, the pollutant concentration is high, the wastewater treatment system is highly loaded, and the effluent quality is difficult to stably meet the standards; 2. During the non-pollution-producing season, the wastewater volume is small and the organic matter concentration is low, the wastewater treatment system lacks carbon sources, and the sludge is prone to aging. Summary of the invention

[0005] In view of this, the present invention discloses a seasonal wastewater double-circulation treatment system to solve the technical problems that the water quality of seasonal wastewater is difficult to stably meet the standards in the pollution-producing season and the sludge is easy to age in the non-pollution-producing season.

[0006] It is also necessary to provide a double-circulation treatment method for seasonal wastewater to solve the technical problems that the water quality of seasonal wastewater is difficult to stably meet the standards during the pollution-producing season and the sludge is prone to aging during the non-pollution-producing season.

[0007] A seasonal wastewater double-circulation treatment system comprises a sedimentation tank, a water quantity and water quality regulating tank, a first reflux device, an aerobic biofilm and activated sludge composite biochemical tank, an activated sludge sedimentation recovery tank, and a gravel filter tank; the water outlet of the water quantity and water quality regulating tank is connected with the water inlet of the aerobic biofilm and activated sludge composite biochemical tank, and the water inlet of the water quantity and water quality regulating tank is higher than the water outlet of the water quantity and water quality regulating tank; the water outlet of the aerobic biofilm and activated sludge composite biochemical tank is connected with the water inlet of the activated sludge sedimentation recovery tank, and the water outlet of the activated sludge sedimentation recovery tank is connected with the water inlet of the gravel filter tank; the sedimentation tank is used to remove particulate matter in the wastewater by gravity sedimentation, and the supernatant in the sedimentation tank is transported to the water quantity and water quality regulating tank by a lifting pump, and the water quantity and water quality regulating tank is used to receive and grade the supernatant in the sedimentation tank, and transport the re-precipitated sewage to the aerobic biofilm and activated sludge composite biochemical tank by gravity self-flow; Activated sludge is arranged in the aerobic biofilm and activated sludge composite biochemical pool, and the sewage entering the aerobic biofilm and activated sludge composite biochemical pool is purified by aeration and oxygen supply; the activated sludge sedimentation and recovery pool is used to separate mud and water from the sewage provided by the aerobic biofilm and activated sludge composite biochemical pool, the supernatant is discharged into the gravel filter tank, and the sludge settled at the bottom is returned to the aerobic biofilm and activated sludge composite biochemical pool; the gravel filter tank filters the supernatant discharged from the activated sludge sedimentation and recovery pool, and discharges the filtered supernatant; the first reflux device is connected to the activated sludge sedimentation and recovery pool and the water quantity and water quality regulating pool, and the first reflux device responds to the first opening operation to transport all the supernatant in the activated sludge sedimentation and recovery pool to the water quantity and water quality regulating pool for circulation treatment; the first reflux device responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation and recovery pool to the water quantity and water quality regulating pool for circulation treatment.

[0008] A seasonal wastewater double-circulation treatment method is applied to a sewage treatment system including a sedimentation tank, an aerobic biofilm and activated sludge composite biochemical tank, an activated sludge sedimentation recovery tank, and a gravel filter tank, and comprises the following steps:

[0009] A water quantity and quality regulating tank is arranged between the sedimentation tank and the aerobic biofilm and activated sludge composite biochemical tank, and the water outlet of the water quantity and quality regulating tank is connected with the water inlet of the aerobic biofilm and activated sludge composite biochemical tank;

[0010] The sedimentation tank is used to remove particulate matter in the wastewater by gravity sedimentation, and the supernatant in the sedimentation tank is transported to the water quantity and quality regulating tank through a lifting pump;

[0011] The water quantity and quality regulating tank is used to collect and grade the supernatant in the sedimentation tank, and the re-precipitated sewage is transported to the aerobic biofilm and activated sludge composite biochemical tank by gravity flow;

[0012] Activated sludge is set in the aerobic biofilm and activated sludge composite biochemical pool, and sewage entering the aerobic biofilm and activated sludge composite biochemical pool is purified by aeration and oxygen supply;

[0013] The activated sludge sedimentation recovery tank is used to separate the sewage provided by the aerobic biofilm and activated sludge composite biochemical tanks into mud and water. The supernatant is discharged into the gravel filter tank, and the sludge settled at the bottom is returned to the aerobic biofilm and activated sludge composite biochemical tanks.

[0014] The supernatant discharged from the activated sludge sedimentation recovery tank is filtered by a gravel filter tank, and the filtered supernatant is discharged;

[0015] The method also includes the following steps: setting a first reflux device between the water quantity and quality regulating tank and the activated sludge sedimentation recovery tank;

[0016] In the non-pollutant-producing season, the first reflux device responds to the first opening operation, and all the supernatant in the activated sludge sedimentation recovery tank is transported to the water quantity and water quality regulating tank for circulation treatment, and the precipitate in the first regulating tank is flushed with the reflux water, and the solid carbon source is further converted into a dissolved state to supplement the wastewater carbon source in the non-pollutant-producing season;

[0017] In the pollution-producing season, the first reflux device responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation recovery tank to the water quantity and quality regulating tank for circulation treatment to ensure that the water quality meets the discharge standards.

[0018] In the above-mentioned seasonal wastewater double-circulation treatment system and method, a water quantity and water quality regulating tank is set between the sedimentation tank and the aerobic biofilm and activated sludge composite biochemical tank, and the outlet of the water quantity and water quality regulating tank is connected with the inlet of the aerobic biofilm and activated sludge composite biochemical tank, and a first reflux device is set between the water quantity and water quality regulating tank and the activated sludge sedimentation recovery tank. In the non-pollution-producing season, the first reflux device responds to the first opening operation to transport all the supernatant in the activated sludge sedimentation recovery tank to the water quantity and water quality regulating tank for circulation treatment, and the precipitate in the first regulating tank is flushed by the reflux water, and the solid carbon source is further converted into a dissolved state to supplement the wastewater carbon source in the non-pollution-producing season. In the pollution-producing season, the first reflux device responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation recovery tank to the water quantity and water quality regulating tank for circulation treatment to ensure that the water quality meets the discharge standards, thereby ensuring that the treated water quality of seasonal wastewater in the pollution-producing season is stable and meets the standards, and ensuring the sludge activity in the non-pollution-producing season. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the module connection of a seasonal wastewater double-circulation treatment system according to a preferred embodiment.

[0020] Figure 2 for Figure 1 Schematic diagram of the structure of the reclaimed water quantity and quality regulating tank.

[0021] In the figure: seasonal wastewater double circulation treatment system 10, sedimentation tank 20, water quantity and quality regulating tank 30, first regulating tank 31, first sludge tank 310, second regulating tank 32, second sludge tank 320, third regulating tank 33, third sludge tank 330, first reflux device 40, aerobic biofilm and activated sludge composite biochemical tank 50, activated sludge sedimentation recovery tank 60, gravel filter 70, ultraviolet disinfection device 80, second reflux device 90, hydraulic circulation pump 100, hanging chain aerator 101. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] like Figure 1As shown, a seasonal wastewater double-circulation treatment system 10 provided by the present invention includes a sedimentation tank 20, a water quantity and water quality regulating tank 30, a first reflux device 40, an aerobic biofilm and activated sludge composite biochemical tank 50, an activated sludge sedimentation recovery tank 60, and a gravel filter 70; the outlet of the water quantity and water quality regulating tank 30 is connected to the water inlet of the aerobic biofilm and activated sludge composite biochemical tank 50, and the water inlet of the water quantity and water quality regulating tank 30 is higher than the outlet of the water quantity and water quality regulating tank 30; the aerobic biofilm and activated sludge composite biochemical tank 50 is connected to the water inlet of the aerobic biofilm and activated sludge composite biochemical tank 50, and the water inlet of the water quantity and water quality regulating tank 30 is higher than the water outlet of the water quantity and water quality regulating tank 30; The outlet of the pool 50 is connected to the inlet of the activated sludge sedimentation recovery pool 60, and the outlet of the activated sludge sedimentation recovery pool 60 is connected to the inlet of the gravel filter 70; the sedimentation pool 20 is used to remove particulate matter in the wastewater by gravity sedimentation, and the supernatant in the sedimentation pool 20 is transported to the water quantity and quality regulating pool 30 through a lifting pump. The water quantity and quality regulating pool 30 is used to receive and grade the supernatant in the sedimentation pool 20, and use gravity to transport the re-precipitated sewage to the aerobic biofilm and activated sludge composite biofilter. aerobic biofilm and activated sludge composite biochemical pool 50 is provided with activated sludge, and the sewage entering the aerobic biofilm and activated sludge composite biochemical pool 50 is purified by aeration and oxygen supply; the activated sludge sedimentation recovery pool 60 is used to separate the sewage provided by the aerobic biofilm and activated sludge composite biochemical pool 50, and the supernatant is discharged into the gravel filter 70, and the sludge settled at the bottom is returned to the aerobic biofilm and activated sludge composite biochemical pool 50; the gravel filter 70 is used for the activated sludge sedimentation recovery pool 6 0 is filtered and the filtered supernatant is discharged; the first reflux device 40 is connected to the activated sludge sedimentation recovery tank 60 and the water quantity and water quality regulating tank 30, and the first reflux device 40 responds to the first opening operation to transport all the supernatant in the activated sludge sedimentation recovery tank 60 to the water quantity and water quality regulating tank 30 for circulation treatment; the first reflux device 40 responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation recovery tank 60 to the water quantity and water quality regulating tank 30 for circulation treatment.

[0024] In this way, in the non-pollutant-producing season, the first reflux device 40 responds to the first opening operation, and all the supernatant in the activated sludge sedimentation recovery tank 60 is transported to the water quantity and water quality regulating tank 30 for circulation treatment, and the reflux water is used to flush the sediment, and further convert the solid carbon source into a dissolved state, so as to supplement the wastewater carbon source in the non-pollutant-producing season. In the pollution-producing season, the first reflux device 40 responds to the third opening operation, and part of the supernatant in the activated sludge sedimentation recovery tank 60 is transported to the water quantity and water quality regulating tank 30 for circulation treatment, so as to ensure that the water quality meets the discharge standard, thereby ensuring that the treated water quality of seasonal wastewater in the pollution-producing season is stable and meets the standard, and ensuring the sludge activity in the non-pollutant-producing season.

[0025] Furthermore, the seasonal wastewater double-circulation treatment system 10 also includes an ultraviolet disinfection device 80, which is arranged at the outlet of the gravel filter 70, so as to use the ultraviolet disinfection device 80 to sterilize the supernatant filtered from the gravel filter.

[0026] Furthermore, the seasonal wastewater double-circulation treatment system 10 also includes a second reflux device 90, which is connected to the activated sludge sedimentation recovery tank 60, the aerobic biofilm and activated sludge composite biochemical tank 50. The second reflux device 90 responds to the second opening operation to return the sludge settled at the bottom of the activated sludge sedimentation recovery tank 60 to the aerobic biofilm and activated sludge composite biochemical tank 50.

[0027] In this embodiment, a movable and detachable screen is provided in the sedimentation tank 20, and the aperture of the screen is greater than 1 cm and less than 3 cm to remove larger particles; a float level gauge is installed in the sedimentation tank to control the operation of the lift pump by the float level; the water quantity and water quality regulating tank 30 includes a first regulating tank 31, a second regulating tank 32, and a third regulating tank 33 connected in sequence, the bottom of the first regulating tank 31 is set with a slope of 15‰, and a first sludge tank 310 is set at the bottom of the outlet side, the first sludge tank 310 is 50 cm wide and 20 cm high, the first sludge tank 310 is used to collect larger particles that have settled down, and anaerobic fermentation is carried out in the first sludge tank 310, and a hydraulic circulation pump 100 is installed in the first sludge tank 310 for hydraulic circulation in the non-production season to promote sedimentation. mixing and anaerobic decomposition; the depth of the second regulating tank 32 and the third regulating tank 33 is two-thirds of the depth of the first regulating tank 31, so as to utilize the first regulating tank 31, the second regulating tank 32 and the third regulating tank 33 to settle suspended particles from large to small, and the second regulating tank 32 and the third regulating tank 33 are also provided with a second sludge tank 320 and a third sludge tank 330 at the bottom of the outlet side, and a hanging chain aerator 101 is provided in the third regulating tank 33, so as to utilize the hanging chain aerator 101 for aeration when the water quality concentration is high in the production season to promote the degradation of organic matter in the water; the water outlets of the first regulating tank 31, the second regulating tank 32 and the third regulating tank 33 are gradually lowered, and the water outlet of the third regulating tank 33 is connected to the water inlet of the aerobic biofilm and activated sludge composite biochemical tank 50.

[0028] In the non-pollutant-producing season, the outlet of the first reflux device 40 is connected to the inlet of the first regulating tank 31. The first reflux device 40 responds to the first opening operation to transport all the supernatant in the activated sludge sedimentation recovery tank 60 to the first regulating tank 31 of the water quantity and water quality regulating tank 30 for circulation treatment. The reflux water is used to flush up the sediment in the first regulating tank 31, and the solid carbon source is further converted into a dissolved state to supplement the wastewater carbon source in the non-pollutant-producing season; in the pollution-producing season, the outlet of the first reflux device 40 is connected to the inlet of the third regulating tank 33. The first reflux device 40 responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation recovery tank 60 to the third regulating tank 33 of the water quantity and water quality regulating tank 30 for circulation treatment to ensure that the water quality meets the discharge standards.

[0029] The present application also provides a seasonal wastewater double-circulation treatment method, which is applied to a sewage treatment system including a sedimentation tank, an aerobic biofilm and activated sludge composite biochemical tank, an activated sludge sedimentation recovery tank, and a gravel filter tank, and comprises the following steps:

[0030] A water quantity and quality regulating tank is set between the sedimentation tank and the aerobic biofilm and activated sludge composite biochemical tank, and the outlet of the water quantity and quality regulating tank is connected with the inlet of the aerobic biofilm and activated sludge composite biochemical tank; wherein, a movable and detachable screen is set in the sedimentation tank, and the aperture of the screen is greater than 1cm and less than 3cm to remove larger particles; a float level gauge is installed in the sedimentation tank to control the operation of the lifting pump through the float level; the water quantity and quality regulating tank includes a first regulating tank, a second regulating tank, and a third regulating tank connected in sequence, the bottom of the first regulating tank is set with a slope of 15‰, and a first sludge tank is set at the bottom of the outlet side, the first sludge tank is 50cm wide and 20cm high, and the first sludge tank is used to collect the larger particles that have settled down, and to carry out Anaerobic fermentation, a hydraulic circulation pump is installed in the first sludge tank for hydraulic circulation in the non-production season to promote the mixing and anaerobic decomposition of sediment; the depth of the second regulating tank and the third regulating tank is two-thirds of the depth of the first regulating tank, so as to utilize the first regulating tank, the second regulating tank and the third regulating tank to settle suspended particles from large to small, and the second sludge tank and the third sludge tank are also provided at the bottom of the outlet side of the second regulating tank and the third regulating tank, and a hanging chain aerator is provided in the third regulating tank to use the hanging chain aerator for aeration when the water quality concentration is high in the production season to promote the degradation of organic matter in the water; the outlets of the first regulating tank, the second regulating tank and the third regulating tank are gradually lowered, and the outlet of the third regulating tank is connected to the water inlet of the aerobic biofilm and activated sludge composite biochemical tank.

[0031] The sedimentation tank is used to remove particulate matter in the wastewater by gravity sedimentation, and the supernatant in the sedimentation tank is transported to the water quantity and quality regulating tank through a lifting pump;

[0032] The water quantity and quality regulating tank is used to collect and grade the supernatant in the sedimentation tank, and the re-precipitated sewage is transported to the aerobic biofilm and activated sludge composite biochemical tank by gravity flow;

[0033] Activated sludge is set in the aerobic biofilm and activated sludge composite biochemical pool, and sewage entering the aerobic biofilm and activated sludge composite biochemical pool is purified by aeration and oxygen supply;

[0034] The activated sludge sedimentation recovery tank is used to separate the sewage provided by the aerobic biofilm and activated sludge composite biochemical tanks into mud and water. The supernatant is discharged into the gravel filter tank, and the sludge settled at the bottom is returned to the aerobic biofilm and activated sludge composite biochemical tanks.

[0035] The supernatant discharged from the activated sludge sedimentation recovery tank is filtered by a gravel filter tank, and the filtered supernatant is discharged;

[0036] Among them, the following steps are also included: a first reflux device is set between the water quantity and water quality regulating tank and the activated sludge sedimentation and recovery tank; in the non-pollution season, the first reflux device responds to the first opening operation, and all the supernatant in the activated sludge sedimentation and recovery tank is transported to the water quantity and water quality regulating tank for circulation treatment, and the sediment in the first regulating tank is flushed with the return water, and the solid carbon source is further converted into a dissolved state to supplement the wastewater carbon source in the non-pollution season, specifically: the outlet of the first reflux device is connected to the water inlet of the first regulating tank, the first reflux device responds to the first opening operation, and all the supernatant in the activated sludge sedimentation and recovery tank is transported to the first regulating tank of the water quantity and water quality regulating tank for circulation treatment, and the sediment in the first regulating tank is flushed with the return water. In the pollution-producing season, the first reflux device responds to the third opening operation, and transports part of the supernatant in the activated sludge sedimentation recovery tank to the water quantity and water quality regulating tank for circulation treatment to ensure that the water quality meets the discharge standards. Specifically, in the pollution-producing season, the outlet of the first reflux device is connected with the inlet of the third regulating tank, and the first reflux device responds to the third opening operation, and transports part of the supernatant in the activated sludge sedimentation recovery tank to the third regulating tank of the water quantity and water quality regulating tank for circulation treatment.

[0037] Furthermore, the above-mentioned seasonal wastewater double-circulation treatment method also includes the following steps: an ultraviolet disinfection device is set at the outlet of the gravel filter to sterilize the supernatant filtered from the gravel filter using the ultraviolet disinfection device.

[0038] Furthermore, the above-mentioned seasonal wastewater double-circulation treatment method also includes the following steps: a second reflux device is set between the aerobic biofilm and activated sludge composite biochemical tank, and the activated sludge sedimentation and recovery tank; the second reflux device responds to the second opening operation to return the sludge settled at the bottom of the activated sludge sedimentation and recovery tank to the aerobic biofilm and activated sludge composite biochemical tank.

Claims

1. A seasonal wastewater double circulation treatment system, characterized in that: It includes a sedimentation tank, a water quantity and water quality regulating tank, a first reflux device, an aerobic biofilm and activated sludge composite biochemical tank, an activated sludge sedimentation recovery tank, and a gravel filter tank; the outlet of the water quantity and water quality regulating tank is connected with the inlet of the aerobic biofilm and activated sludge composite biochemical tank, and the inlet of the water quantity and water quality regulating tank is higher than the outlet of the water quantity and water quality regulating tank; The outlet of the aerobic biofilm and activated sludge composite biochemical tank is connected to the inlet of the activated sludge sedimentation recovery tank, and the outlet of the activated sludge sedimentation recovery tank is connected to the inlet of the gravel filter tank; the sedimentation tank is used to remove particulate matter in the wastewater by gravity sedimentation, and the supernatant in the sedimentation tank is transported to the water quantity and quality regulating tank through a lifting pump. The water quantity and quality regulating tank is used to receive and grade the supernatant in the sedimentation tank, and use gravity to transport the re-precipitated sewage to the aerobic biofilm and activated sludge composite biochemical tank; The activated sludge is arranged in the aerobic biofilm and activated sludge composite biochemical pool, and the sewage entering the aerobic biofilm and activated sludge composite biochemical pool is purified by aeration and oxygen supply; The activated sludge sedimentation recovery tank is used to separate the sewage provided by the aerobic biofilm and activated sludge composite biochemical tanks into mud and water. The supernatant is discharged into the gravel filter tank, and the sludge settled at the bottom is returned to the aerobic biofilm and activated sludge composite biochemical tanks. The gravel filter tank filters the supernatant discharged from the activated sludge sedimentation recovery tank and discharges the filtered supernatant; the first reflux device is connected to the activated sludge sedimentation recovery tank and the water quantity and water quality regulating tank. The first reflux device responds to the first opening operation to transport all the supernatant in the activated sludge sedimentation recovery tank to the water quantity and water quality regulating tank for circulation treatment; the first reflux device responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation recovery tank to the water quantity and water quality regulating tank for circulation treatment; the water quantity and water quality regulating tank includes the first regulating tank, the second regulating tank connected in sequence, and the second regulating tank. The first regulating pool and the third regulating pool are respectively provided with a slope of 15‰ at the bottom of the first regulating pool and a first sludge tank with a width of 50cm and a height of 20cm. The first sludge tank is used to collect the larger particles that have settled down and to carry out anaerobic fermentation in the first sludge tank. A hydraulic circulation pump is installed in the first sludge tank for hydraulic circulation in the non-production season to promote the mixing and anaerobic decomposition of the sediment. The depths of the second regulating pool and the third regulating pool are two-thirds of the depths of the first regulating pool, so as to utilize the first regulating pool, the second regulating pool and the third regulating pool to settle the suspended particles from large to small. particles, and the second regulating tank and the third regulating tank are also provided with a second sludge tank and a third sludge tank at the bottom of the outlet side. A hanging chain aerator is provided in the third regulating tank to use the hanging chain aerator for aeration when the water quality concentration is high in the production season to promote the degradation of organic matter in the water; the outlets of the first regulating tank, the second regulating tank and the third regulating tank are gradually lowered, and the outlet of the third regulating tank is connected with the inlet of the aerobic biofilm and activated sludge composite biochemical tank; in the non-pollutant production season, the outlet of the first reflux device is connected with the inlet of the first regulating tank, and the first reflux device responds to the first opening operation The supernatant in the activated sludge sedimentation recovery tank is completely transported to the first regulating tank of the water quantity and water quality regulating tank for circulation treatment, and the sediment in the first regulating tank is flushed by the return water, and the solid carbon source is further converted into a dissolved state to supplement the wastewater carbon source in the non-pollutant-producing season; in the pollution-producing season, the outlet of the first reflux device is connected to the inlet of the third regulating tank, and the first reflux device responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation recovery tank to the third regulating tank (33) of the water quantity and water quality regulating tank for circulation treatment to ensure that the water quality meets the discharge standards.

2. A seasonal wastewater double circulation treatment system as claimed in claim 1, characterized in that: It also includes an ultraviolet disinfection device, which is arranged at the water outlet of the gravel filter tank to sterilize the supernatant filtered from the gravel filter tank by using the ultraviolet disinfection device.

3. A seasonal wastewater double circulation treatment system as claimed in claim 1 or 2, characterized in that: It also includes a second reflow device, which is connected to the activated sludge sedimentation and recovery tank, the aerobic biofilm and the activated sludge composite biochemical tank. The second reflow device responds to the second opening operation to return the sludge settled at the bottom of the activated sludge sedimentation and recovery tank to the aerobic biofilm and the activated sludge composite biochemical tank.

4. A seasonal wastewater double circulation treatment system as claimed in claim 3, characterized in that: A movable and detachable screen is set in the sedimentation tank, and the aperture of the screen is greater than 1cm and less than 3cm to remove larger particles; a float level gauge is installed in the sedimentation tank to control the operation of the lift pump through the float liquid level.

5. A seasonal wastewater double-circulation treatment method, which is applied to a sewage treatment system including a sedimentation tank, an aerobic biofilm and activated sludge composite biochemical tank, an activated sludge sedimentation recovery tank, and a gravel filter tank, and comprises the following steps: A water quantity and quality regulating pool is arranged between the sedimentation pool and the aerobic biofilm and activated sludge composite biochemical pool, the water quantity and quality regulating pool comprising a first regulating pool, a second regulating pool, and a third regulating pool connected in sequence, and a water outlet of the water quantity and quality regulating pool is connected to a water inlet of the aerobic biofilm and activated sludge composite biochemical pool; The sedimentation tank is used to remove particulate matter in the wastewater by gravity sedimentation, and the supernatant in the sedimentation tank is transported to the water quantity and quality regulating tank through a lifting pump; The water quantity and quality regulating tank is used to collect and grade the supernatant in the sedimentation tank, and the re-precipitated sewage is transported to the aerobic biofilm and activated sludge composite biochemical tank by gravity flow; Activated sludge is set in the aerobic biofilm and activated sludge composite biochemical pool, and sewage entering the aerobic biofilm and activated sludge composite biochemical pool is purified by aeration and oxygen supply; The activated sludge sedimentation recovery tank is used to separate the sewage provided by the aerobic biofilm and activated sludge composite biochemical tanks into mud and water. The supernatant is discharged into the gravel filter tank, and the sludge settled at the bottom is returned to the aerobic biofilm and activated sludge composite biochemical tanks. The supernatant discharged from the activated sludge sedimentation recovery tank is filtered by a gravel filter tank, and the filtered supernatant is discharged; The method also includes the following steps: setting a first reflux device between the water quantity and quality regulating tank and the activated sludge sedimentation recovery tank; In the non-pollutant-producing season, the first reflux device responds to the first opening operation, and all the supernatant in the activated sludge sedimentation recovery tank is transported to the water quantity and water quality regulating tank for circulation treatment, and the precipitate in the first regulating tank is flushed with the reflux water, and the solid carbon source is further converted into a dissolved state to supplement the wastewater carbon source in the non-pollutant-producing season; In the pollution-producing season, the first reflux device responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation recovery tank to the water quantity and quality regulating tank for circulation treatment to ensure that the water quality meets the discharge standards.

6. The seasonal wastewater double circulation treatment method according to claim 5, characterized in that: The following steps are also included: An ultraviolet disinfection device is arranged at the water outlet of the gravel filter tank so as to sterilize the supernatant filtered from the gravel filter tank by the ultraviolet disinfection device.

7. The seasonal wastewater double circulation treatment method according to claim 5 or 6, characterized in that: The following steps are also included: A second reflux device is arranged between the aerobic biofilm and activated sludge composite biochemical tank and the activated sludge sedimentation recovery tank; The second reflow device responds to the second opening operation to return the sludge settled at the bottom of the activated sludge sedimentation recovery tank to the aerobic biofilm and activated sludge composite biochemical tank.

8. The seasonal wastewater double circulation treatment method according to claim 7, characterized in that: A movable and detachable screen is set in the sedimentation tank, and the aperture of the screen is greater than 1cm and less than 3cm to remove larger particles; a float level gauge is installed in the sedimentation tank to control the operation of the lift pump through the float liquid level.

9. The seasonal wastewater double circulation treatment method according to claim 7, characterized in that: The bottom of the first regulating tank is set with a slope of 15‰, and a first sludge tank is set at the bottom of the outlet side. The first sludge tank is 50cm wide and 20cm high. The first sludge tank is used to collect larger particles that have settled down, and anaerobic fermentation is carried out in the first sludge tank. A hydraulic circulation pump is installed in the first sludge tank for hydraulic circulation in the non-production season to promote the mixing and anaerobic decomposition of sediment; the depths of the second regulating tank and the third regulating tank are two-thirds of the depth of the first regulating tank, so as to utilize the first regulating tank, the second regulating tank and the third regulating tank to settle suspended particles from large to small, and the second sludge tank and the third sludge tank are also set at the bottom of the outlet side of the second regulating tank and the third regulating tank. A hanging chain aerator is set in the third regulating tank to use the hanging chain aerator for aeration when the water quality concentration is high in the production season to promote the degradation of organic matter in the water; the first regulating tank and the second regulating tank The outlets of the pool and the third regulating pool are gradually lowered, and the outlet of the third regulating pool is connected with the inlet of the aerobic biofilm and activated sludge composite biochemical pool; in the non-pollution season, the outlet of the first reflux device is connected with the inlet of the first regulating pool, and the first reflux device responds to the first opening operation to transport all the supernatant in the activated sludge sedimentation recovery pool to the first regulating pool of the water quantity and water quality regulating pool for circulation treatment, and the precipitate in the first regulating pool is flushed with the return water, and the solid carbon source is further converted into a dissolved state to supplement the wastewater carbon source in the non-pollution season; in the pollution season, the outlet of the first reflux device is connected with the inlet of the third regulating pool, and the first reflux device responds to the third opening operation to transport part of the supernatant in the activated sludge sedimentation recovery pool to the third regulating pool of the water quantity and water quality regulating pool for circulation treatment, so as to ensure that the water quality meets the discharge standards.

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