CN104787989B - A kind of deep well aeration pond and the method for waste water enhanced nitrogen removal dephosphorization device and waste water enhanced nitrogen removal dephosphorization - Google Patents

Abstract

The invention relates to a deep well aeration tank, a wastewater enhanced denitrification and phosphorus removal device and a wastewater enhanced denitrification and phosphorus removal method. It relates to a deep well aeration tank, a waste water treatment device and a waste water treatment method. The invention provides a water treatment method and device suitable for treating urban sewage, especially urban sewage in Northeast China, with small floor space, low energy consumption, and simple operation and maintenance. The deep well aeration tank includes an outer cylinder of the deep well aeration tank, an inner cylinder of the deep well aeration tank, a degassing tank and an aeration device. Wastewater enhanced nitrogen and phosphorus removal device includes water storage tank, anaerobic tank, anoxic tank, deep well aeration tank, first degassing tank, second degassing tank, secondary settling tank, water inlet pump, sludge return pump, nitrifying liquid Return pump, drain port and mud valve. Methods for enhanced denitrification and phosphorus removal of waste water: 1. domesticate activated sludge in the deep well aeration tank; The waste water enhanced denitrification and dephosphorization device of the present invention has a treatment capacity per unit land area of 20,000 cubic meters/day.m ² , an organic load of more than 0.8kgBOD/kgMLSS, and a high utilization rate of dissolved oxygen.

Description

A deep well aeration tank, wastewater enhanced nitrogen and phosphorus removal device, and wastewater enhanced nitrogen and phosphorus removal Phosphorus method

technical field

The invention relates to a deep well aeration tank, a waste water treatment device and a waste water treatment method.

Background technique

Water resources are the basic conditions for the survival of human beings, and also the basic prerequisite for the sustainable development of my country's economy. my country's total water resources rank among the top in the world, but the per capita water resources are less than 1/4 of the world average.

With the development of our country's economy, the growth of population, the acceleration of industrialization and urban development, the water consumption is also increasing, the discharge of sewage is also increasing, and the pollution of surface water and groundwater is becoming more and more serious, making water resources scarce. situation is getting worse. By 2007, my country's sewage discharge will reach 105 billion tons. Such a large amount of sewage discharge directly and seriously affects the normal life and health of human beings, seriously threatens human life and health, hinders the sustainable development of economy, and threatens the ecological balance of nature. Therefore, sewage purification treatment is necessary and important. Recycling and reuse of sewage after purification can improve the utilization rate of water resources, reduce the pressure brought by water resources, alleviate the contradiction of water shortage, and can greatly reduce the pollution of natural water systems, so as to achieve the ecological balance of protecting water resources and nature.

Today's cities are getting more and more crowded, especially in developed cities. It can be said that every inch of land is expensive. Many cities do not have enough land to build sewage treatment plants, and commonly used sewage treatment processes such as A2O, oxidation ditch and other processes often require a large amount of land for construction, so they cannot be realized.

The construction of sewage plants in small towns has the problems of easy construction and difficult operation and maintenance, and sewage treatment plants are likely to have a greater impact on the surrounding environment, especially VOC (volatile organic compounds) will cause great inconvenience to the lives of people around the water plant.

Contents of the invention

The purpose of the present invention is to provide a water treatment method and device with small footprint, low energy consumption and simple operation and maintenance.

The deep well aeration tank of the present invention comprises an outer cylinder of the deep well aeration tank, an inner cylinder of the deep well aeration tank, a degassing tank and an aeration device, and the water inlet and the aeration device of the deep well aeration tank are arranged at the inner bottom of the inner cylinder of the aeration tank.

Utilize the wastewater enhanced nitrogen and phosphorus removal device of the above-mentioned deep well aeration tank, the wastewater enhanced nitrogen and phosphorus removal device includes a water storage tank, anaerobic tank, anoxic tank, deep well aeration tank, first degassing tank, and second degassing tank , secondary settling tank, water inlet pump, sludge return pump, nitrifying liquid return pump, drain port and sludge discharge valve;

The anaerobic tank, the anoxic tank, the first degassing tank and the second degassing tank are equipped with agitators; the water storage tank is connected to the anaerobic tank and the anoxic tank respectively through the water inlet pump; The anoxic tank is connected with the anaerobic tank, the anaerobic tank is connected with the deep well aeration tank through the inlet pump, the deep well aeration tank is connected with the second degassing tank, the second degassing tank is connected with the secondary sedimentation tank The secondary settling tank is connected with the first degassing tank through the sludge return pump, and the deep well aeration tank is connected with the first degassing tank through the nitrification liquid return pump; the drain is set on the upper part of the secondary settling tank; the sludge discharge valve Set at the bottom of the secondary sedimentation tank.

The method for enhancing denitrification and dephosphorization of wastewater by using the above-mentioned wastewater enhanced denitrification and dephosphorization device:

1. Domesticate activated sludge in the deep well aeration tank;

2. Pass the domesticated activated sludge and sewage in the deep well aeration tank into the anaerobic tank, anoxic tank, the first degassing tank, the second degassing tank, and the secondary sedimentation tank; then turn on the water inlet pump and aerate device and agitator, the sewage in the water storage tank enters the anaerobic pool and the anoxic pool respectively, the water inflow of the anaerobic pool is 25% to 75% of the total water output of the water storage tank, and the water inflow of the anoxic pool is the water storage tank 75% to 25% of the total water output; the sewage in the anoxic tank is stirred and mixed and then pushed into the anaerobic tank. The sewage from the anoxic tank and the water storage tank is mixed in the anaerobic tank and then pumped into the deep well aeration tank The sewage in the aeration tank forms an airlift cycle under the action of aeration, and the sewage flows upward along the inner cylinder of the deep well aeration tank into the outer cylinder of the deep well aeration tank. Enter the second degassing tank, mix and stir in the second degassing tank, push the flow into the secondary settling tank, the sludge in the secondary settling tank flows back into the first degassing tank through the sludge return pump, and the nitrification in the deep well aeration tank The liquid flows back into the first degassing tank through the nitrifying liquid return pump, and the sludge and nitrifying liquid are mixed and stirred in the first degassing tank, and then pushed into the anoxic tank;

3. The water treated by the secondary sedimentation tank is discharged through the drain, and the remaining sludge is discharged through the sludge discharge valve; that is, the enhanced denitrification and phosphorus removal of wastewater is completed;

Among them, the dissolved oxygen concentration of the anaerobic tank is less than 0.2 mg/L, the dissolved oxygen concentration of the anoxic tank is 0.2-0.5 mg/L, and the dissolved oxygen concentration in the middle of the deep well aeration tank is 3.2 mg/L; the hydraulic retention of the anoxic tank The time is 1.0-3.0h, the hydraulic retention time of the anaerobic tank is 1.0-3.0h, the hydraulic retention time of the deep well aeration tank is 0.5-2.0h, the hydraulic retention time of the secondary sedimentation tank is 2.5h, and the first degassing tank and the hydraulic retention time of the second degassing tank is 0.5h; the sludge return ratio from the secondary settling tank to the first degassing tank is 50% to 100%, and the sludge returning from the deep well aeration tank to the first degassing tank The reflux ratio of the nitrification solution is 100% to 300%.

The present invention adopts an improved deep well aeration tank with a depth of more than 50 meters, thin and high, and has the advantages of small footprint, and an air lift cycle is formed in the deep well aeration tank. Under the same aeration conditions, the deep well aeration tank of the present invention can The utilization rate of dissolved oxygen in the aeration tank is higher.

The deep well aeration tank of the present invention enters water from the bottom of the inner cylinder of the deep well aeration tank, and the sewage rises along the inner cylinder under the action of the driving force of the aeration device, and then descends in the outer cylinder of the deep well aeration tank, forming an air lift cycle. Dissolved oxygen gradually decreases during the process of sewage rising from the bottom of the deep well aeration tank to the top degassing tank, forming an alternation of aerobic and anoxic states, which can form denitrification and denitrification, and enhance the denitrification effect.

The waste water enhanced denitrification and dephosphorization device of the present invention has a treatment capacity per unit land area of 20,000 cubic meters per day.m ² , which is much higher than the current treatment process.

In the existing A2O process, the raw water directly enters the anaerobic section, most of the influent carbon source is consumed in the anaerobic section, and the available carbon source in the anoxic section is relatively small, resulting in insufficient denitrification carbon source and partial nitrogen removal rate. Low. According to the invention, the influent water enters the anaerobic section and the anoxic section respectively, the carbon source is distributed reasonably, the denitrification effect is enhanced, and the denitrifying phosphorus accumulating bacteria in the anoxic section is strengthened at the same time, so as to save the carbon source.

In the present invention, the sludge from the secondary settling tank and the nitrifying liquid in the deep well aeration tank flow back to the first degassing tank, and part of the dissolved oxygen can be consumed in the first degassing tank, reducing the interference of the nitrifying liquid backflow on the anoxic tank and the anaerobic tank . At the same time, a lower dissolved oxygen environment can also be formed in the first degassing tank, which can form denitrification and denitrification to promote the denitrification effect.

In the present invention, the effluent from the anaerobic tank directly enters the deep well aeration tank to complete the release and absorption of phosphorus by the phosphorus accumulating bacteria, which is beneficial to the removal of phosphorus.

The invention has strong impact load resistance, and the invention has strong impact load resistance, and the organic load is above 0.8kgBOD/kgMLSS.

The operation and maintenance of the invention is simple, and the human workload is low.

The invention is suitable for treating industrial sewage and urban domestic sewage, and can efficiently remove nitrogen and phosphorus in sewage. The COD, ammonia nitrogen, total nitrogen, and total phosphorus in the effluent treated by the invention are reduced to 28-46 mg/L and 1.8-3.3 mg/L respectively. L, 6.9~8.1mg/L, 0.19~0.31mg/L, better than GB18918-2002 Class A emission standard.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the deep well aeration tank of the present invention, and the arrows represent the direction of water flow.

Fig. 2 is a schematic structural diagram of the waste water enhanced denitrification and dephosphorization device of the present invention, and the arrows represent the direction of material movement.

detailed description

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

Specific embodiment 1: This embodiment is described in conjunction with Figure 1. The deep well aeration tank in this embodiment includes the outer cylinder of the deep well aeration tank, the inner cylinder 4-2 of the deep well aeration tank, the degassing tank 4-3, and the aeration device 4- 1 and an air inlet pipe 15, characterized in that the water inlet of the deep well aeration tank and the aeration device 4-1 are all arranged at the inner bottom of the aeration tank inner tube 4-2, and the air inlet pipe 15 communicates with the aeration device 4-1.

Specific Embodiment 2: This embodiment is described in conjunction with FIG. 2 . The wastewater enhanced denitrification and phosphorus removal device in this embodiment includes a water storage tank 1, an anaerobic pool 2, an anoxic pool 3, a deep well aeration pool 4, and a first degassing pool 5. , the second degassing tank 6, the secondary settling tank 7, the water inlet pump 10, the sludge return pump 11, the nitrifying liquid return pump 12, the drain port 13 and the sludge discharge valve 14;

The anaerobic pool 2, the anoxic pool 3, the first degassing pool 5 and the second degassing pool 6 are equipped with agitators 9; the water storage tank 1 is connected with the anaerobic pool 2 and the anoxic pool 3 respectively through the water inlet pump 10 ; The first degassing tank 5 is communicated with anoxic tank 3, and anoxic tank 3 is communicated with anaerobic tank 2, and anaerobic tank 2 is communicated with deep well aeration tank 4 by inlet pump 10, and deep well aeration tank 4 is connected with The second degassing tank 6 is connected, the second degassing tank 6 is connected with the secondary sedimentation tank 7, the secondary sedimentation tank 7 is connected with the first degassing tank 5 through the sludge return pump 11, and the deep well aeration tank 4 is connected by nitrification The liquid return pump 12 is in communication with the first degassing tank 5; the drain port 13 is set on the upper part of the secondary settling tank 7; the sludge discharge valve 14 is set on the bottom of the secondary settling tank 7.

Specific embodiment three: this embodiment is described in conjunction with Fig. 2, and the method for the enhanced denitrification and phosphorus removal of waste water in this embodiment is carried out according to the following steps:

1. Domesticated activated sludge in the deep well aeration tank 4;

Two, pass the activated sludge and sewage domesticated in the deep well aeration tank 4 to the anaerobic tank 2, the anoxic tank 3, the first degassing tank 5, the second degassing tank 6, the secondary sedimentation tank 7; then Turn on the water inlet pump 10, the aeration device 4-1 and the agitator 9, and the sewage in the water storage tank 1 enters the anaerobic pool 2 and the anoxic pool 3 respectively, and the water inflow of the anaerobic pool 2 is the total water output of the water storage tank 1 25% to 75% of the water in the anoxic pool 3, and the water inflow to the anoxic pool 3 is 75% to 25% of the total water output from the water storage tank 1; Stir and mix with the sewage in the water storage tank 1 in the anaerobic tank 2, then pump 10 into the deep well aeration tank 4, the sewage in the deep well aeration tank 4 forms a gas lift cycle under the action of aeration, and the sewage flows along the inner tube 4 of the deep well aeration tank -2 flows upward into the outer cylinder of the deep well aeration tank, and the sewage is treated in the inner cylinder 4-2 of the deep well aeration tank to form nitrifying liquid, which pushes into the second degassing tank 6 and mixes and stirs in the second degassing tank 6 The push flow enters the secondary settling tank 7, the sludge in the secondary settling tank 7 flows back into the first degassing tank 5 through the sludge return pump 11, and the nitrifying liquid in the deep well aeration tank 4 flows back into the first degassing tank 5 through the nitrifying liquid return pump 12. A degassing tank 5, the sludge and nitrification liquid are mixed and stirred in the first degassing tank 5, and then pushed into the anoxic tank 3;

3. The water treated by the secondary settling tank 7 is discharged through the outlet 13, and the remaining sludge is discharged through the sludge discharge valve 14; that is, the enhanced denitrification and phosphorus removal of wastewater is completed;

Among them, the dissolved oxygen concentration in the anaerobic tank 2 is less than 0.2 mg/L, the dissolved oxygen concentration in the anoxic tank 3 is 0.2-0.5 mg/L, and the dissolved oxygen concentration in the middle of the deep well aeration tank 4 is 3.2 mg/L; The hydraulic retention time of 3 is 1.0-3.0h, the hydraulic retention time of anaerobic tank 2 is 1.0-3.0h, the hydraulic retention time of deep well aeration tank 4 is 0.5-2.0h, and the hydraulic retention time of secondary sedimentation tank 7 is 2.5 h, the hydraulic retention time of the first degassing tank 5 and the second degassing tank 6 is 0.5h; the sludge reflux ratio from the secondary settling tank 7 to the first degassing tank 5 is 50% to 100%. The reflux ratio of the nitrification liquid from the aeration tank 4 to the first degassing tank 5 is 100%-300%.

In this embodiment, the returning sludge and returning nitrifying liquid are degassed in the first degassing tank 5, and then enter the anoxic section after removing part of the dissolved oxygen.

In this embodiment, the effluent from the anaerobic tank 2 directly enters the deep well aeration tank 4 to complete the release and absorption of microbial phosphorus.

Specific embodiment four: the difference between this embodiment and specific embodiment three is: the activated sludge in the deep well aeration tank 4 is domesticated by the following method in the step one: the secondary sedimentation tank sludge and fresh sewage that the sewage plant is taken are poured out Enter the deep well aeration tank 4, turn on the aeration device 4-1 and incubate for 10 days at a temperature of about 25°C to obtain domesticated activated sludge. Other steps and parameters are the same as those in the third embodiment.

Embodiment five: the difference between this embodiment and embodiment three or four is: the rotating speed of the agitator in the anoxic pool 3 in step 2 is 30r/min～50r/min; the rotating speed of the agitator in the anaerobic pool 2 30r/min～50r/min; the rotational speed of the agitator in the second degassing pool 6 is 30r/min～50r/min; the rotational speed of the agitator in the first degassing pool 5 is 30r/min～50r/min. Other steps and parameters are the same as those in Embodiment 3 or 4.

Embodiment 6: The difference between this embodiment and Embodiment 3, 4 or 5 is that in step 2, biofilm fillers are added in deep well aeration tank 4, anaerobic tank 2 and anoxic tank 3. Other steps and parameters are the same as those in Embodiment 3, 4 or 5.

In this embodiment, biofilm fillers are added to the deep well aeration tank 4, the anaerobic tank 2 and the anoxic tank 3, which can increase the biomass and improve the turbulence of the water body. The degree of turbulence of the multiphase fluid in this embodiment is characterized by a shear strength of not less than 0.3.

Embodiment 7: The difference between this embodiment and Embodiment 3, 4, 5 or 6 is that in step 2, the steam-water ratio in the deep well aeration tank 4 is 1.2-1.5:1. Other steps and parameters are the same as those in Embodiment 3, 4, 5 or 6.

In this embodiment, with the change of water flow depth, the pressure and dissolved oxygen concentration of activated sludge are constantly adjusted and changed, the utilization rate of dissolved oxygen in water is significantly improved, the consumption rate of organic matter is increased, and there is a relatively obvious denitrification effect.

Embodiment 8: The difference between this embodiment and Embodiment 4, 5, 6 or 7 is: the COD value of the fresh sewage in step 1 is 215mg/L～550mg/L, and the ammonia nitrogen value is 32mg/L～55mg/L L, the total nitrogen value is 38mg/L~62mg/L, and the total phosphorus value is 3.9mg/L~7.4mg/L. Other steps and parameters are the same as Embodiments 4, 5, 6 or 7.

Specific embodiment nine: the difference between this embodiment and one of the specific embodiments three to eight is: the sewage in the water storage tank 1 enters the anaerobic pool 2 and the anoxic pool 3 respectively in the step 2, and the anaerobic pool 2 and the anoxic pool The water inflow ratio of pool 3 is 1:2, 1:1 or 2:1. Other steps and parameters are the same as those of Embodiments 3 to 8.

Example 1

The method for enhanced denitrification and dephosphorization of waste water is carried out according to the following steps:

1. Domesticated activated sludge in the deep well aeration tank 4;

Two, pass the activated sludge and sewage domesticated in the deep well aeration tank 4 to the anaerobic tank 2, the anoxic tank 3, the first degassing tank 5, the second degassing tank 6, the secondary sedimentation tank 7; then Turn on the water inlet pump 10, the aeration device 4-1 and the agitator 9, and the sewage in the water storage tank 1 enters the anaerobic pool 2 and the anoxic pool 3 respectively, and the water inflow of the anaerobic pool 2 is the total water output of the water storage tank 1 25% to 75% of the water in the anoxic pool 3, and the water inflow to the anoxic pool 3 is 75% to 25% of the total water output from the water storage tank 1; Stir and mix with the sewage in the water storage tank 1 in the anaerobic tank 2, then pump 10 into the deep well aeration tank 4, the sewage in the deep well aeration tank 4 forms a gas lift cycle under the action of aeration, and the sewage flows along the inner tube 4 of the deep well aeration tank -2 flows upward into the outer cylinder of the deep well aeration tank, and the sewage is treated in the inner cylinder 4-2 of the deep well aeration tank to form nitrifying liquid, which pushes into the second degassing tank 6 and mixes and stirs in the second degassing tank 6 The push flow enters the secondary settling tank 7, the sludge in the secondary settling tank 7 flows back into the first degassing tank 5 through the sludge return pump 11, and the nitrifying liquid in the deep well aeration tank 4 flows back into the first degassing tank 5 through the nitrifying liquid return pump 12. A degassing tank 5, the sludge and nitrification liquid are mixed and stirred in the first degassing tank 5, and then pushed into the anoxic tank 3;

3. The water treated by the secondary settling tank 7 is discharged through the outlet 13, and the remaining sludge is discharged through the sludge discharge valve 14; that is, the enhanced denitrification and phosphorus removal of wastewater is completed;

Among them, the dissolved oxygen concentration in the anaerobic tank 2 is less than 0.2 mg/L, the dissolved oxygen concentration in the anoxic tank 3 is 0.2-0.5 mg/L, and the dissolved oxygen concentration in the middle of the deep well aeration tank 4 is 3.2 mg/L; The hydraulic retention time of 3 is 1.0-3.0h, the hydraulic retention time of anaerobic tank 2 is 1.0-3.0h, the hydraulic retention time of deep well aeration tank 4 is 0.5-2.0h, and the hydraulic retention time of secondary sedimentation tank 7 is 2.5 h, the hydraulic retention time of the first degassing tank 5 and the second degassing tank 6 is 0.5h; the sludge reflux ratio from the secondary settling tank 7 to the first degassing tank 5 is 50% to 100%. The reflux ratio of the nitrifying liquid from the aeration tank 4 to the first degassing tank 5 is 100% to 300%;

Among them, the activated sludge in the deep well aeration tank 4 in step 1 is domesticated according to the following method: pour the secondary sedimentation tank sludge and fresh sewage from the sewage plant into the deep well aeration tank 4, open the aeration device 4-1 Cultivate for 10 days at a temperature of 25°C to obtain domesticated activated sludge;

The speed of the agitator in the anoxic pool 3 in step 2 is 30r/min～50r/min; the speed of the agitator in the anaerobic pool 2 is 30r/min～50r/min; the speed of the agitator in the second degassing pool 6 30r/min-50r/min; the rotational speed of the agitator in the first degassing tank 5 is 30r/min-50r/min.

The COD value of the pretreated sewage in the water storage tank 1 is 215mg/L-550mg/L, the ammonia nitrogen value is 32mg/L-55mg/L, the total nitrogen value is 38mg/L-62mg/L, and the total phosphorus value is 3.9mg/L L～7.4mg/L.

Example 2

Except that the deep well aeration device (CN201210244816.X) is used to replace the deep well aeration tank of the present invention, and all the sewage in the water storage tank 1 enters the anoxic tank 3, other water treatment reactors and parameters are the same as in Example 1.

The pretreated sewage is the same as in Example 1, the COD value of the pretreated sewage in the water storage tank 1 is 215mg/L～550mg/L, the ammonia nitrogen value is 32mg/L～55mg/L, and the total nitrogen value is 38mg/L～62mg/L L, the total phosphorus value is 3.9mg/L～7.4mg/L.

Experimental results:

After the treatment in Example 1, the COD value of the effluent was 28-46 mg/L, the ammonia nitrogen value was 1.8-3.3 mg/L, the total nitrogen value was 6.9-8.1 mg/L, and the total phosphorus value was 0.19-0.31 mg/L, reaching the national Tier 1 A emission standard.

After the treatment in Example 2, the effluent COD value is 31-51 mg/L, the ammonia nitrogen value is 2.8-4.6 mg/L, the total nitrogen value is 9.6-15.4 mg/L, and the total phosphorus value is 0.21-0.37 mg/L, which can basically reach Meet the national level A emission standard.

Experimental results prove that the utilization rate of dissolved oxygen in the deep well aeration tank of the present invention is high, and the effect of denitrification and denitrification (enhanced denitrification effect) is produced in the deep well aeration tank; the influent carbon source is reasonably allocated, and the pollutant removal ability is strengthened , the purification effect is obviously better than that of Example 2, especially the denitrification effect. The invention achieves the deep reduction of pollutants under the conditions of small floor area and low energy consumption, and plays a positive role in the prevention and control of water pollution and the protection of water environment.

Claims (7)

1. The wastewater enhanced denitrification and phosphorus removal device is used to carry out the wastewater enhanced denitrification and phosphorus removal method, which is characterized in that the wastewater enhanced nitrogen and phosphorus removal method is carried out according to the following steps: 1. Activated sludge is domesticated in the deep well aeration tank (4); 2. Pass the domesticated activated sludge and sewage in the deep well aeration tank (4) into the anaerobic tank (2), the anoxic tank (3), the first degassing tank (5), and the second degassing tank (6), secondary settling tank (7); then open water inlet pump, aeration device (4-1) and agitator, the sewage in the water storage tank (1) enters anaerobic pond (2) and anoxic pond ( In 3), the water intake of the anaerobic pool (2) is 25% to 75% of the total water output of the water storage tank (1), and the water intake of the anoxic pool (3) is 75% of the total water output of the water storage tank (1). ~25%; the sewage in the anoxic pool (3) is stirred and mixed and then pushed into the anaerobic pool (2), and the sewage from the anoxic pool (3) and the water storage tank (1) is stirred and mixed in the anaerobic pool (2) After pumping into the deep well aeration tank (4), the sewage in the deep well aeration tank (4) forms an air lift cycle under the action of aeration, and the sewage flows upward along the inner tube (4-2) of the deep well aeration tank to the outside of the deep well aeration tank Cylinder, the sewage is processed in the inner cylinder (4-2) of the deep well aeration tank to form nitrifying liquid, and the nitrifying liquid is pushed into the second degassing tank (6), mixed and stirred in the second degassing tank (6) and then pushed to flow Enter the secondary settling tank (7), the sludge in the secondary settling tank (7) flows back into the first degassing tank (5) through the sludge return pump (11), and the nitrifying liquid in the deep well aeration tank (4) passes through the nitrification The liquid reflux pump (12) flows back into the first degassing tank (5), and the sludge and nitrification liquid are mixed and stirred in the first degassing tank (5), and then pushed into the anoxic tank (3); 3. The water treated by the secondary settling tank (7) is discharged through the outlet (13), and the remaining sludge is discharged through the sludge discharge valve (14); that is, the enhanced denitrification and phosphorus removal of wastewater is completed; Among them, the dissolved oxygen concentration in the anaerobic tank (2) is less than 0.2 mg/L, the dissolved oxygen concentration in the anoxic tank (3) is 0.2-0.5 mg/L, and the dissolved oxygen concentration in the middle of the deep well aeration tank (4) is 3.2 mg /L; the hydraulic retention time of anoxic tank (3) is 1.0～3.0h, the hydraulic retention time of anaerobic tank (2) is 1.0～3.0h, and the hydraulic retention time of deep well aeration tank (4) is 0.5～2.0 h, the hydraulic retention time of the secondary settling tank (7) is 2.5h, and the hydraulic retention time of the first degassing tank (5) and the second degassing tank (6) is 0.5h; The sludge reflux ratio of the first degassing tank (5) is 50% to 100%, and the reflux ratio of the nitrifying liquid from the deep well aeration tank (4) to the first degassing tank (5) is 100% to 300%; Among them, the wastewater enhanced nitrogen and phosphorus removal device includes a water storage tank (1), anaerobic tank (2), anoxic tank (3), deep well aeration tank (4), first degassing tank (5), second degassing tank Air tank (6), secondary settling tank (7), water inlet pump, sludge return pump (11), nitrification liquid return pump (12), drain outlet (13) and sludge discharge valve (14); The anaerobic tank (2), the anoxic tank (3), the first degassing tank (5) and the second degassing tank (6) are equipped with agitators; (2), the anoxic pond (3) is connected; the first degassing pond (5) is connected with the anoxic pond (3), and the anoxic pond (3) is connected with the anaerobic pond (2). (2) communicate with the deep well aeration tank (4) through the water inlet pump, the deep well aeration tank (4) is connected with the second degassing tank (6), and the second degassing tank (6) is connected with the secondary sedimentation tank (7) ), the secondary settling tank (7) is connected with the first degassing tank (5) through the sludge return pump (11), and the deep well aeration tank (4) is connected with the first degassing tank through the nitrification liquid return pump (12) The pools (5) are connected; the drain outlet (13) is arranged on the upper part of the secondary sedimentation tank (7); and the mud discharge valve (14) is arranged on the bottom of the secondary sedimentation tank (7). 2. the method for strengthening denitrification and dephosphorization of wastewater according to claim 1 is characterized in that the activated sludge in the deep well aeration tank (4) is domesticated by the following method in step 1: the secondary sedimentation tank sewage that the sewage plant is taken is The mud and fresh sewage are poured into the deep well aeration tank (4), the aeration device (4-1) is turned on and cultured at a temperature of 25°C for 10 days to obtain domesticated activated sludge. 3. the method for strengthening denitrification and dephosphorization of wastewater according to claim 1 is characterized in that the rotating speed of the agitator in the anoxic pool (3) in step 2 is 30r/min～50r/min; the anaerobic pool (2) The rotating speed of the agitator in the middle is 30r/min～50r/min; the rotating speed of the agitator in the second degassing tank (6) is 30r/min～50r/min; the rotating speed of the agitator in the first degassing tank (5) is 30r/min～50r/min. 4. the method for strengthening denitrification and dephosphorization of wastewater according to claim 1 is characterized in that in step 2, add biological film filler. 5. The method for enhanced denitrification and dephosphorization of wastewater according to claim 1, characterized in that in step 2, the steam-water ratio in the deep well aeration tank (4) is 1.2 to 1.5:1. 6. The method for enhanced denitrification and dephosphorization of wastewater according to claim 2, characterized in that in step 1, the COD value of the fresh sewage is 215mg/L～550mg/L, the ammonia nitrogen value is 32mg/L～55mg/L, the total The nitrogen value is 38mg/L-62mg/L, and the total phosphorus value is 3.9mg/L-7.4mg/L. 7. The method for strengthening denitrification and dephosphorization of waste water according to claim 1, characterized in that the sewage in the water storage tank (1) enters anaerobic pond (2) and anoxic pond (3) respectively in step 2, anaerobic The water inflow ratio of the pool (2) to the anoxic pool (3) is 1:2, 1:1 or 2:1.