Sewage treatment equipment applied to cold regions

Abstract

The application discloses a sewage treatment equipment applied to cold regions, which comprises a hydrolytic acidification treatment tank, an anoxic reaction tank, an aerobic reaction tank, a screening tank, a primary sedimentation tank and a secondary sedimentation tank; a first gas stripping device is arranged in the hydrolytic acidification treatment tank; the anoxic reaction tank is communicated with the bottom of the hydrolytic acidification tank; the aerobic reaction tank is communicated with the upper portion of the anoxic reaction tank; the screening tank is communicated with the bottom of the aerobic reaction tank; the primary sedimentation tank is communicated with the upper portion of the screening tank; and the secondary sedimentation tank is communicated with the upper portion of the primary sedimentation tank. The sewage treatment equipment can perform multi-stage sedimentation on sewage, can also screen activated sludge, forms high-concentration agglomerated biochemical sludge, and can treat biological sewage in cold regions in the north, and can also realize sludge backflow, supplement nutrients and biochemical bacteria for the front end.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and more particularly to a wastewater treatment device that can be applied in cold regions. Background Technology

[0002] Existing small-scale sewage treatment equipment still uses conventional sewage treatment methods when treating sewage in cold regions. However, in winter in cold regions, the activity of biological sludge is poor due to temperature, resulting in poor sewage treatment effect.

[0003] Therefore, it is necessary to continue to provide a wastewater treatment device that can be applied to cold regions for the treatment of domestic sewage in cold regions. Summary of the Invention

[0004] The purpose of this invention is to provide a wastewater treatment device suitable for cold regions to solve the above-mentioned problems.

[0005] The present invention solves the technical problem by adopting the following technical solution:

[0006] A wastewater treatment device for cold regions includes a hydrolysis acidification treatment tank, an anoxic reaction tank, an aerobic reaction tank, a screening tank, a primary sedimentation tank, and a secondary sedimentation tank that are connected in sequence.

[0007] The hydrolysis acidification treatment tank is equipped with a first air-lift device, which is connected to a blower via a pipeline.

[0008] The anoxic reaction tank is connected to the bottom of the hydrolysis acidification tank. The bottom of the anoxic reaction tank is equipped with a perforated aeration pipe, which is connected to a blower through a pipeline.

[0009] The aerobic reaction tank is connected to the anoxic reaction tank at the top. The aerobic reaction tank is equipped with a microporous aerator, which is connected to a blower through a pipeline. A bottom purge pipe is installed at the bottom of the aerobic reaction tank, located below the microporous aerator, and is connected to a blower through a pipeline. A second air-lift device is also installed at the end of the aerobic reaction tank, which is connected to a blower through a pipeline.

[0010] The screening tank is connected to the bottom of the aerobic reaction tank, and the bottom plate of the screening tank is inclined.

[0011] The primary sedimentation tank is connected to the upper part of the screening tank. The primary sedimentation tank is equipped with a central pipe and a third air-lift device. The third air-lift device is connected to a blower through a pipeline. The central pipe is sleeved on the outside of the third air-lift device.

[0012] The secondary sedimentation tank is connected to the upper part of the primary sedimentation tank. A vertical pipe is installed in the secondary sedimentation tank. A baffle assembly is installed at the bottom of the vertical pipe, and a fourth air-lift device is installed inside it. The fourth air-lift device is connected to a blower through a pipeline. A dosing device is installed above the secondary sedimentation tank, and a sludge discharge device is installed at the bottom.

[0013] Furthermore, the first air lifting device includes a first air pipe and a first outer pipe. The first air pipe is vertically arranged and connected to a blower through a pipeline. The first outer pipe is sleeved on the outside of the first air pipe, and its bottom is spaced apart from the bottom of the hydrolysis acidification tank. The distance between the bottom of the first air pipe and the bottom of the first outer pipe is 200-300mm.

[0014] Furthermore, the perforated aeration pipe is formed into a circular pipe, with one end sealed and the other end connected to the blower through a pipeline; a small hole is opened on the lower wall of the perforated aeration pipe; the diameter of the small hole is 3-5mm.

[0015] Furthermore, the second airlift device includes a second air pipe, a second outer pipe, and an inclined pipe. The second air pipe is vertically arranged and connected to a blower through a pipeline. The second outer pipe is sleeved on the outside of the second air pipe, and its bottom is spaced apart from the bottom of the aerobic reaction tank. The distance between the bottom of the second air pipe and the bottom of the second outer pipe is 200-300mm. The upper end of the inclined pipe is connected to the upper part of the second outer pipe, and the lower end passes through the second partition and extends into the anoxic reaction tank.

[0016] Furthermore, the inclination angle of the inclined tube is 30°-40°.

[0017] Furthermore, the treated wastewater in the aerobic reaction tank enters the screening tank from the bottom of the third baffle, and the angle between the bottom plate of the screening tank and the horizontal plane is 60°-65°; the bottom of the third baffle bends away from the aerobic reaction tank, and the bent part accounts for 1 / 8-1 / 6 of the total length of the third baffle 300.

[0018] Furthermore, the central tube includes a straight tube and a tapered tube disposed at the bottom of the straight tube. The diameter of the smaller end of the tapered tube is the same as the diameter of the straight tube. The connecting tube is connected to the side wall of the straight tube and is interconnected with it. The third air lifting device includes a third air pipe, a third outer pipe, and a slow-descent pipe. The third air pipe is vertically arranged and connected to a blower through a pipeline. The third outer pipe is sleeved on the outside of the third air pipe, and its bottom is spaced apart from the bottom of the primary sedimentation tank. The distance between the bottom of the third air pipe and the bottom of the third outer pipe is 200-300mm. The upper end of the slow-descent pipe is connected to the upper part of the third outer pipe, and the lower end passes through the fourth partition, the third partition, the second partition, and the first partition in sequence, extending into the hydrolysis acidification tank. The upper end of the slow-descent pipe is 50-100mm above the liquid surface, and half of the lower end is submerged in the water.

[0019] Furthermore, the tilt angle of the descent tube is 3°-5°.

[0020] Furthermore, the fourth air-lift device includes a fourth air pipe and a fourth outer pipe. The fourth air pipe is connected to a blower via a pipeline, and the fourth outer pipe is sleeved on the outside of the fourth air pipe. The baffle assembly includes a reducing pipe and a reversing plate. A cross-shaped plate is provided inside the reducing pipe, and the reversing plate is located below the reducing pipe and spaced apart from it. The diameter of the smaller end of the reducing pipe is the same as the diameter of the vertical pipe. The reversing plate is conical, and its axis coincides with the axis of the reducing pipe. The sludge discharge device includes a sludge discharge pipe and a valve installed on the sludge discharge pipe. One end of the sludge discharge pipe is located at the bottom of the secondary sedimentation tank, and the other end extends outward from the side plate at the middle position of the water level.

[0021] The dosing device includes a dosing hopper and a dosing pump. The dosing hopper is located at the top of the secondary sedimentation tank and its bottom is formed into a cone shape. A fifth air pipe is also installed in the dosing hopper, and the fifth air pipe is connected to a blower through a pipeline. The dosing pump is installed at the top of the dosing hopper.

[0022] The present invention has the following beneficial effects: the wastewater treatment equipment of the present invention can perform multi-stage sedimentation of wastewater through multiple interconnected tanks, and can also screen activated sludge to form high-concentration agglomerated biochemical sludge to treat biological wastewater in cold northern regions. At the same time, it can also realize sludge return to replenish nutrients and biochemical bacteria at the front end. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the wastewater treatment equipment of the present invention;

[0024] Figure 2 This is a schematic diagram of the variable diameter pipe in this invention.

[0025] The markings in the diagram are as follows: 1-Hydrolysis acidification tank; 2-Anoxic reaction tank; 3-Aerobic reaction tank; 4-Screening tank; 5-Primary sedimentation tank; 6-Secondary sedimentation tank; 7-First air pipe; 8-First outer pipe; 9-Perforated aeration pipe; 10-Microporous aerator; 11-Bottom purge pipe; 12-Second outer pipe; 13-Inclined pipe; 16-Connecting pipe; 18-Third outer pipe; 19-Central pipe; 21-Slow descent pipe; 22-Fourth air pipe; 23-Sludge removal device; 24-Reversing plate; 25-Baffle assembly; 26-Vertical pipe; 27-Fourth outer pipe; 29-Dosing device; 30-Blower; 31-Second air pipe; 32-Third air pipe; 100-First baffle; 200-Second baffle; 300-Third baffle; 400-Fourth baffle; 500-Fifth baffle. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0027] Example 1

[0028] like Figure 1 As shown, a wastewater treatment device for cold regions includes a hydrolysis acidification treatment tank 1, an anoxic reaction tank 2, an aerobic reaction tank 3, a screening tank 4, a primary sedimentation tank 5, and a secondary sedimentation tank 6, which are connected in sequence.

[0029] In this embodiment, the wastewater treatment equipment includes a reaction tank, which is equipped with a first baffle 100, a second baffle 200, a third baffle 300, a fourth baffle 400, and a fifth partition 500. The first baffle, second baffle, third baffle, fourth baffle, and fifth partition divide the internal area of ​​the reaction tank into interconnected hydrolysis acidification tank 1, an anoxic reaction tank 2, an aerobic reaction tank 3, a sludge screening tank 4, a primary sedimentation tank 5, and a secondary sedimentation tank 6. The reaction tank is also equipped with an inlet and an outlet.

[0030] Specifically, the hydrolysis acidification treatment tank 1 is equipped with a first air lifting device, which includes a first air pipe 7 and a first outer pipe 8. The first air pipe 7 is vertically arranged and connected to the blower 30 through a pipeline. The first outer pipe 8 is sleeved on the outside of the first air pipe 7, and its bottom is spaced apart from the bottom of the hydrolysis acidification tank. The distance between the bottom of the first air pipe and the bottom of the first outer pipe is 200-300mm.

[0031] In this embodiment, the blower 30 supplies air to the first air pipe 7 through a pipeline. The air entering the first air pipe 7 is discharged from the bottom of the first air pipe 7. A large number of air bubbles form a mixture with the sewage in the first outer pipe 8. Due to the low density of the air-water mixture, it flows upward along the first outer pipe 8 under the action of buoyancy. At the same time, sewage flows in from the lower end of the first outer pipe 8 to replenish it, forming a hydraulic circulation, thereby agitating the sewage in the hydrolysis acidification tank and preventing sludge from settling in the water. On the other hand, the oxygen content in the water can also be adjusted by regulating the amount of air entering the first air pipe 7.

[0032] The wastewater entering the hydrolysis acidification tank 1 undergoes a process where large organic molecules are broken down into smaller organic molecules by the first air stripping device. The wastewater is then acidified by acidifying bacteria to complete the initial screening of bacterial strains and prepare for pretreatment in subsequent treatment units.

[0033] Continue to refer to Figure 1 The anoxic reaction tank 2 is connected to the bottom of the hydrolysis acidification tank 1, and the treated wastewater in the hydrolysis acidification tank 1 enters the anoxic reaction tank 2 from the bottom of the first partition 100.

[0034] Specifically, a perforated aeration pipe 9 is provided at the bottom of the anoxic reaction tank 2. The perforated aeration pipe 9 is formed into a circular pipe, one end of which is sealed, and the other end is connected to the blower 30 through a pipeline. Small holes are opened on the lower wall of the perforated aeration pipe 9. Preferably, the diameter of the small holes is 3-5 mm.

[0035] In this embodiment, the blower 30 supplies air to the perforated aeration pipe 9 through a pipeline. The air enters the water through small holes in the perforated aeration pipe. Since the perforated aeration pipe is located at the bottom of the anoxic reaction tank, the air can agitate the wastewater, thereby preventing sludge sedimentation. On the other hand, the bubbles discharged from the perforated aeration pipe are relatively large, which can intensify the agitation of the wastewater. Moreover, the dissolution effect of air in water is relatively weak. Therefore, the dissolved oxygen concentration inside the anoxic reaction tank can be controlled by adjusting the air intake of the perforated aeration pipe to meet the requirements of the anoxic reaction tank. Preferably, the dissolved oxygen index inside the anoxic reaction tank is 0.1-0.5 mg / L.

[0036] The aerobic reaction tank 3 is connected to the upper part of the anoxic reaction tank 2, and the treated wastewater in the anoxic reaction tank 2 enters the aerobic reaction tank 3 from above the second partition 200.

[0037] Specifically, the aerobic reaction tank 3 is equipped with a microporous aerator 10, which is connected to the blower 30 via a pipeline; a bottom purge pipe 11 is provided at the bottom of the aerobic reaction tank 3, which is located below the microporous aerator 10 and is connected to the blower 30 via a pipeline; a second air lift device is also provided at the end of the aerobic reaction tank 1, which is connected to the blower 30 via a pipeline.

[0038] The second air lifting device includes a second air pipe 31, a second outer pipe 12, and an inclined pipe 13. The second air pipe 31 is vertically arranged and connected to the blower 30 through a pipeline. The second outer pipe 12 is sleeved on the outside of the second air pipe 31, and its bottom is spaced apart from the bottom of the aerobic reaction tank 3. The distance between the bottom of the second air pipe 31 and the bottom of the second outer pipe 12 is 200-300mm. The upper end of the inclined pipe 13 is connected to the upper part of the second outer pipe 12, and the lower end passes through the second partition 200 and extends into the anoxic reaction tank 2.

[0039] In this embodiment, the microporous aerator 10 provides sufficient oxygen to the aerobic reaction tank, and the bottom purge pipe is used to purge the bottom of the aerobic reaction tank to prevent sludge sedimentation, with a purge frequency of 30s / 2h. The diameter of the second outer pipe is 50-100mm, and the inclination angle of the inclined pipe is 30°-40°. A blower supplies air to the second air pipe through a pipeline. The air is discharged from the bottom of the second air pipe and rises inside the second outer pipe, creating an airlift phenomenon. This causes the wastewater inside the second outer pipe to rise rapidly. When the wastewater reaches a high level, it flows into the anoxic reaction tank along the inclined pipe, ultimately completing the nitrification liquid return. Furthermore, the top of the second outer pipe is open, allowing excess air to be released, thus preventing excess air from entering the anoxic reaction tank and causing the dissolved oxygen concentration inside the anoxic reaction tank to exceed the standard.

[0040] The screening tank 4 is connected to the bottom of the aerobic reaction tank 3, and the treated wastewater in the aerobic reaction tank 3 enters the screening tank 4 from the bottom of the third partition 300.

[0041] Specifically, the bottom plate of the screening tank 4 is inclined, and the angle between it and the horizontal plane is 60°-65°; the bottom of the third partition 300 is bent away from the aerobic reaction tank 3, and the bent part accounts for 1 / 8-1 / 6 of the total length of the third partition 300.

[0042] In this embodiment, after the activated sludge in the aerobic reaction tank 3 enters the screening tank, it flows upward in the screening tank, while the sludge particles in the wastewater simultaneously settle downward due to gravity. When the settling velocity of the activated sludge is greater than the vertical upward water flow velocity, the activated sludge will produce a settling effect. Since different activated sludges have different settling velocities, the activated sludge can be screened by controlling the upward flow velocity of the wastewater, thereby retaining the useful clump-shaped activated sludge and discharging the loose sludge from the system. Preferably, the upward flow velocity of the wastewater can be controlled by adjusting the horizontal cross-sectional area of ​​the screening tank. In this embodiment, the upward flow velocity of the wastewater in the screening tank is set to 8-15 m / h.

[0043] The primary sedimentation tank 5 is connected to the upper part of the screening tank 4. The loose activated sludge screened out in the screening tank 4 enters the primary sedimentation tank 5 along with the sewage through the connecting pipe 16 set on the fourth partition 400.

[0044] Specifically, the bottom of the primary sedimentation tank 5 is formed in a cone shape. The primary sedimentation tank 5 is equipped with a central pipe 19 and a third air-lift device. The central pipe 19 is connected to the connecting pipe 16. The third air-lift device is connected to the blower 30 through a pipeline. The central pipe 19 is sleeved on the outside of the third air-lift device.

[0045] The central tube 19 includes a straight tube and a tapered tube at the bottom of the straight tube. The diameter of the smaller end of the tapered tube is the same as the diameter of the straight tube. The connecting tube 16 is connected to the side wall of the straight tube and they are interconnected. The third air lifting device includes a third air pipe 32, a third outer pipe 18, and a slow-descent pipe 21. The third air pipe 32 is vertically arranged and connected to the blower 30 through a pipeline. The third outer pipe 18 is sleeved on the outside of the third air pipe 32, and its bottom is spaced apart from the bottom of the primary sedimentation tank 5. The distance between the bottom of the third air pipe 32 and the bottom of the third outer pipe 18 is 200-300mm. The upper end of the slow-descent pipe 21 is connected to the upper part of the third outer pipe 18, and the lower end passes through the fourth partition 400, the third partition 300, the second partition 200, and the first partition 100 in sequence, extending into the hydrolysis acidification tank 1. The upper end of the slow-descent pipe 21 is 50-100mm above the liquid surface, and half of the lower end is submerged in the water. Preferably, the tilt angle of the descent tube 21 is 3°-5°.

[0046] In this embodiment, the treated wastewater in the screening tank 4 enters the central pipe 19 through the connecting pipe 16. The wastewater flows into the lower part of the primary sedimentation tank through the central pipe, and the heavier sludge settles into the bottom cone. The blower supplies air to the third air pipe through the pipeline. The air is discharged from the bottom of the third air pipe and floats inside the third outer pipe, thus forming an air lift phenomenon, which drives the wastewater inside the third outer pipe to rise rapidly. At the same time, wastewater with settled sludge flows in from the lower end of the third outer pipe to replenish it. When the wastewater reaches the high level, it will be transported to the hydrolysis acidification tank through the inclined slow-descent pipe, thereby replenishing nutrients and biochemical bacteria to the front end.

[0047] The secondary sedimentation tank 6 is connected to the upper part of the primary sedimentation tank 5. The treated wastewater in the primary sedimentation tank 5 enters the secondary sedimentation tank 6 through the first effluent weir set on the fifth partition 500.

[0048] Specifically, the bottom of the secondary sedimentation tank 6 is formed in a cone shape. A vertical pipe 26 is provided in the secondary sedimentation tank 6. The vertical pipe 26 is connected to the first effluent weir through a pipeline. A baffle assembly 25 is provided at the bottom of the vertical pipe 26, and a fourth air-lift device is provided inside it. The fourth air-lift device is connected to a blower 30 through a pipeline. A dosing device 29 is provided above the secondary sedimentation tank 6, and a sludge discharge device 23 is provided at the bottom.

[0049] The fourth air lifting device includes a fourth air pipe 22 and a fourth outer pipe 27. The fourth air pipe 22 is connected to the blower 30 through a pipeline, and the fourth outer pipe 27 is sleeved on the outside of the fourth air pipe 22. The baffle assembly 25 includes a reducing pipe and a reversing plate 24. A cross-shaped plate is provided inside the reducing pipe, and the reversing plate 24 is located below the reducing pipe and spaced apart from it. The diameter of the smaller end of the reducing pipe is the same as the diameter of the vertical pipe. The reversing plate 24 is formed into a cone shape, and the axis of the reversing plate 24 coincides with the axis of the reducing pipe. The sludge discharge device 23 includes a sludge discharge pipe and a valve provided on the sludge discharge pipe. One end of the sludge discharge pipe is located at the bottom of the secondary sedimentation tank, and the other end extends outward from the side plate at the middle position of the water level.

[0050] The dosing device 29 includes a dosing hopper and a dosing pump. The dosing hopper is located at the top of the secondary sedimentation tank and its bottom is formed into a cone shape. A fifth air pipe 14 is also provided in the dosing hopper, and the fifth air pipe 14 is connected to the blower 30 through a pipeline. A dosing pump is provided at the top of the dosing hopper, and the dosing pump is used to add the agent in the dosing hopper to the secondary sedimentation tank.

[0051] In this embodiment, the treated wastewater in the primary sedimentation tank enters the vertical pipe through the first effluent weir. The water is agitated by the fourth air-lift device, promoting the dissolution and reaction of the chemicals. The wastewater resides in the vertical pipe for 3-6 minutes; this prolonged residence time disperses the precipitated flocs, preventing further sedimentation. The fully reacted wastewater enters the reducing pipe and flows slowly downwards under the action of the cross-shaped plate. Near the reversing plate, it begins to flow upwards, creating a zero-velocity point at the turning point, facilitating sedimentation and separation. The clarified water after secondary sedimentation is discharged through the sedimentation tank outlet, while the sludge is discharged through the sludge discharge pipe. Preferably, the sedimentation tank outlet is equipped with an effluent weir.

[0052] The wastewater treatment equipment of the present invention can perform multi-stage sedimentation of wastewater through multiple interconnected tanks, and can also screen activated sludge to form high-concentration agglomerated biochemical sludge to treat biological wastewater in cold northern regions. At the same time, it can also realize sludge return to replenish nutrients and biochemical bacteria at the front end.

[0053] The order of the above embodiments is for ease of description only and does not represent the superiority or inferiority of the embodiments.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wastewater treatment device for use in cold regions, characterized in that, The sewage treatment equipment comprises a reaction tank, wherein a first baffle, a second baffle, a third baffle, a fourth baffle and a fifth baffle are arranged in the reaction tank, and the first baffle, the second baffle, the third baffle, the fourth baffle and the fifth baffle divide the area inside the reaction tank into a hydrolysis acidification tank, an anoxic reaction tank, an aerobic reaction tank, a screening tank, a primary sedimentation tank and a secondary sedimentation tank which are in communication with each other; The hydrolysis acidification tank is provided with a first gas stripping device, and the first gas stripping device is connected with a fan through a pipeline; The anoxic reaction tank is communicated with the bottom of the hydrolysis acidification tank, and the bottom of the anoxic reaction tank is provided with a perforated aeration pipe which is connected with the fan through a pipeline; The aerobic reaction tank is communicated with the upper portion of the anoxic reaction tank, and the aerobic reaction tank is provided with a microporous aerator which is connected with the fan through a pipeline; the bottom of the aerobic reaction tank is provided with a bottom blowing pipe which is located below the microporous aerator and is connected with the fan through a pipeline; and the end of the aerobic reaction tank is further provided with a second gas stripping device which is connected with the fan through a pipeline; The screening tank is communicated with the bottom of the aerobic reaction tank, and the bottom plate of the screening tank is arranged in an inclined manner; The primary sedimentation tank is communicated with the upper portion of the screening tank, and the primary sedimentation tank is provided with a central pipe and a third gas stripping device which is connected with the fan through a pipeline, and the central pipe is sleeved outside the third gas stripping device; The secondary sedimentation tank is communicated with the upper portion of the primary sedimentation tank, and the secondary sedimentation tank is provided with a vertical pipe, the bottom of the vertical pipe is provided with a partition assembly, and the inside of the vertical pipe is provided with a fourth gas stripping device which is connected with the fan through a pipeline; the upper portion of the secondary sedimentation tank is provided with a dosing device, and the bottom of the secondary sedimentation tank is further provided with a sludge discharge device; The first gas stripping device comprises a first gas pipe and a first outer pipe, the first gas pipe is arranged in a vertical manner and is connected with the fan through a pipeline, the first outer pipe is sleeved outside the first gas pipe, and the bottom of the first outer pipe is arranged in a spaced manner with the bottom of the hydrolysis acidification tank; and the distance between the bottom of the first gas pipe and the bottom of the first outer pipe is 200-300 mm; The second gas stripping device comprises a second gas pipe, a second outer pipe and an inclined pipe, the second gas pipe is arranged in a vertical manner and is connected with the fan through a pipeline, the second outer pipe is sleeved outside the second gas pipe, and the bottom of the second outer pipe is arranged in a spaced manner with the bottom of the aerobic reaction tank; the distance between the bottom of the second gas pipe and the bottom of the second outer pipe is 200-300 mm; and the upper end of the inclined pipe is communicated with the upper portion of the second outer pipe, the lower end of the inclined pipe penetrates through the second baffle and extends into the anoxic reaction tank. The center pipe comprises a straight pipe and a conical pipe arranged at the bottom of the straight pipe, the diameter of the smaller end of the conical pipe is the same as that of the straight pipe, the communicating pipe is connected with the sidewall of the straight pipe and communicates with each other; the third gas lifting device comprises a third gas pipe, a third outer pipe and a slow descending pipe, the third gas pipe is vertically arranged and connected with the fan through a pipeline, the third outer pipe is sleeved outside the third gas pipe and is arranged at the bottom of the first stage sedimentation tank; the distance between the bottom of the third gas pipe and the bottom of the third outer pipe is 200-300 mm; the upper end of the slow descending pipe communicates with the upper part of the third outer pipe, the lower end sequentially penetrates through the fourth baffle, the third baffle, the second baffle and the first baffle and extends into the hydrolysis acidification tank, and the upper end of the slow descending pipe is 50-100 mm higher than the liquid level and the lower end is half immersed in water; The fourth gas lifting device comprises a fourth gas pipe and a fourth outer pipe, the fourth gas pipe is connected with the fan through a pipeline, and the fourth outer pipe is sleeved outside the fourth gas pipe; the baffle assembly comprises a reducing pipe and a reversing plate, the reducing pipe is internally provided with a cross-shaped plate, the reversing plate is arranged below the reducing pipe and is spaced apart from the reducing pipe; the diameter of the smaller end of the reducing pipe is the same as that of the vertical pipe, the reversing plate is formed in a conical shape, and the axis of the reversing plate coincides with the axis of the reducing pipe; the sludge discharge device comprises a sludge discharge pipe and a valve arranged on the sludge discharge pipe, one end of the sludge discharge pipe is arranged at the bottom of the second stage sedimentation tank, and the other end penetrates out from the side plate at the middle position of the water level height; The dosing device comprises a dosing hopper and a dosing pump, the dosing hopper is arranged at the top of the second stage sedimentation tank and is formed in a conical shape at the bottom, a fifth gas pipe is further arranged in the dosing hopper, and the fifth gas pipe is connected with the fan through a pipeline; the top of the dosing hopper is provided with the dosing pump; The treated wastewater in the aerobic reaction tank enters the screening tank from the bottom of the third baffle, the included angle between the bottom plate of the screening tank and the horizontal plane is 60°-65°; the bottom of the third baffle is bent away from the aerobic reaction tank, and the bent part accounts for 1 / 8-1 / 6 of the total length of the third baffle.

2. The sewage treatment apparatus for cold regions according to claim 1, characterized by The perforated aeration pipe is formed in a circular tube, one end of which is sealed and the other end of which is connected with the fan through a pipeline; a plurality of small holes are arranged on the lower wall of the perforated aeration pipe; the diameter of the small holes is 3-5 mm.

3. The sewage treatment apparatus for cold regions according to claim 1, characterized by The inclination angle of the inclined pipe is 30°-40°.

4. The sewage treatment equipment for cold regions according to claim 1, characterized by The inclination angle of the slow descending pipe is 3°-5°.

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