CN108640415B - Efficient backwashing artificial ecological sewage land treatment system - Google Patents

Abstract

The invention discloses a high-efficiency backwashing artificial ecological sewage land treatment system which comprises a tank body, wherein impervious films are paved on the periphery and the bottom of the tank body, and the tank body is respectively provided with an anaerobic zone, an aerobic zone and a sedimentation zone from left to right. The anaerobic zone and the aerobic zone are respectively a sand layer, a supporting layer, a filler layer, a gas collecting layer and a soil layer from bottom to top, and the sedimentation zone is respectively a sand layer, a sludge layer, a mud-water separating layer, a gas collecting layer and a soil layer from bottom to top. The anaerobic zone, the aerobic zone and the sedimentation zone are respectively provided with a plurality of air pipes and a sludge discharge branch pipe, the air outlet holes of the air pipes are positioned at the bottom of the filler layer or the bottom of the sludge layer, the sludge discharge branch pipe is positioned below the liquid level of the tank body, a plurality of sludge discharge holes are formed in the pipe wall, and the sludge discharge branch pipe is connected with a vacuum device or a valve. Compared with the existing filtering system, the invention has the advantages that no external clear water back flushing is needed, and a back flushing water pump, a separate flushing pipeline and a valve are not needed. The system has the characteristics of simple equipment, convenient management, low manufacturing cost, low energy consumption and low operation cost.

Description

A highly efficient backwashing artificial ecological sewage land treatment system

Technical Field

The invention relates to a sewage treatment system, in particular to a high-efficiency backwashing artificial ecological sewage land treatment system, belonging to the technical field of environmental protection.

Background technique

The sewage land treatment system has the advantages of low investment, simple operation and management, stable treatment effect, and decentralized treatment, which is very suitable for sewage treatment in small towns. With the extension of operation time, after exceeding a certain operation time, due to the accumulation of inorganic suspended matter intercepted and filtered, aging and shedding of biofilm, etc., the system will experience problems such as decreased effluent volume, increased head loss, poor treatment effect, and system blockage. The system must be backwashed regularly to remove suspended matter to restore the treated water volume and treatment effect. The quality of the backwashing effect of the sewage land treatment system is related to the effect and stability of the system operation.

The traditional air-water combined backwashing method has the following defects:

(1) The backwashing device needs to be equipped with a high-power water pump, a separate flushing air pipe, a water distribution pipe and a valve, which is expensive;

(2) Backwash water needs to overcome the gravity pressure difference when passing through the filter layer from bottom to top, which consumes a lot of energy;

(3) During backwashing, a large amount of clean water needs to be introduced from outside the system, which consumes a large amount of clean water;

(4) The valve needs to be switched, which makes the operation complicated.

The Chinese patent with publication number CN 103449665 A discloses a sewage land biological sedimentation filtration system for mud-water separation, which achieves good mud-water separation and solid suspended matter removal effects and improves the effluent quality by organically combining biological adsorption, mechanical filtration and micro-sedimentation separation technology. However, it still needs to set up a backwashing device, use an enhanced air-water combined backwashing method for backwashing, or use water or air alone for backwashing.

Summary of the invention

In view of the defects and shortcomings of the above-mentioned traditional technologies, the purpose of the present invention is to provide an artificial ecological sewage land treatment system that does not require external clean water backwashing, backwashing pumps, separate flushing pipes and valves for sequential interval backwashing.

The technical solution described in the present invention is as follows: it comprises a trough body excavated under the ground, the trough body is covered with an impermeable membrane around and at the bottom, the trough body is divided into an anaerobic zone, an aerobic zone, and a sedimentation zone from left to right, the anaerobic zone and the aerobic zone are filled with a sand layer, a supporting layer, a filler layer, an air collection layer, and a soil layer from bottom to top, and the sedimentation zone is filled with a sand layer, a sludge layer, a mud-water separation layer, an air collection layer, and a soil layer from bottom to top. The two sides of the trough body are respectively provided with a water inlet and a water outlet; the trough body is also provided with an air pipe and a mud discharge branch pipe, the air outlet of the air pipe is located at the bottom of the filler layer or the bottom of the sludge layer, and the mud discharge branch pipe is located below the liquid level of the trough body; the highest liquid level of the trough body is located at the bottom of the gas collection layer.

The anaerobic zone, aerobic zone and sedimentation zone are all provided with a plurality of independently controlled air pipes and mud discharge branch pipes.

One end of the air pipe is connected to the external blower of the system, and the middle is connected to the air pipe valve.

The mud discharge branch pipe wall is provided with a plurality of mud discharge holes, a vacuum device is installed on the mud discharge branch pipe outlet, and extends upward to the gas collection layer and extends out of the trough body, or a mud discharge branch pipe valve is installed on the mud discharge branch pipe outlet and extends out of the trough body.

One end of the sewage return pipe is located at the end of the aerobic zone in the packing layer, and the other end is connected to the water inlet.

The supporting layer, filler layer, sludge layer, mud-water separation layer and gas collection layer are all filled with fillers, and the fillers are gravel or other granular fillers; the particle size of the supporting layer and sludge layer fillers is 20-80mm, the particle size of the filler layer and mud-water separation layer fillers is 10-60mm, and the particle size of the gas collection layer fillers is 20-80mm.

When the accumulated sludge in the system reaches a certain amount, there is no need to close the water inlet and outlet. The air flow rate of the backwash section is adjusted to the backwash air flow rate, and one or more sections of the anaerobic zone, aerobic zone or sedimentation zone of the system are backwashed with air and water. It is only necessary to open the vacuum device or the mud discharge branch pipe valve, and use the air and the filter material gap water in the non-flushing area around the system to backwash the filler layer, sludge layer and mud-water separation layer. The sludge is discharged from the sewage land treatment system through the mud discharge branch pipe. When the backwashing of this section is completed, the mud discharge branch pipe valve is closed or the mud discharge siphon is destroyed to stop the mud discharge. At the same time, if the backwashing section is in the anaerobic zone or the sedimentation zone, the air pipe valve is closed. If the backwashing section is in the aerobic zone, the air flow rate is reduced to the amount of air required for oxygen supply. The backwashing process of this section ends, and the biological filtration or sedimentation filtration working mode is entered. The system backwashes the next section and completes the sequential section backwashing operation.

The duration of air backwashing is generally 1-10 minutes, the air backwashing intensity is 4-22L/ ^m2 ·s, and the water backwashing intensity is 2-10L/ ^m2 ·s. The use of air backwashing can not only improve the backwashing effect, but also has an oxygenating effect, which is conducive to the aerobic degradation and purification of pollutants in sewage by microorganisms and improves the effluent water quality.

The present invention has the following advantages:

1. Compared with the traditional backwashing method, the filter material gap water in the surrounding non-washing area is directly used as backwashing water, without the need to introduce external clean water, thus saving flushing water;

2. Directly use the head difference between the inside and outside of the filter as the backwashing power, no need for backwashing pumps, separate flushing pipes and valves, simple operation;

3. Use air backwashing to improve the backwashing effect;

4. The mud discharge branch pipe uses the vacuum device or valve on the siphon device to control the mud discharge;

5. Compared with the existing filtering backwashing system, the equipment is simple, easy to operate, low in cost, low in energy consumption and low in operating cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the external structure of specific embodiments 1 and 2 of the present invention.

Fig. 2 is a schematic cross-sectional view of the anaerobic zone and the aerobic zone taken along line A-A of the specific embodiment 1 of the present invention.

Fig. 3 is a schematic cross-sectional view of the anaerobic zone and the aerobic zone taken along line A-A according to a specific embodiment 2 of the present invention.

Fig. 4 is a schematic diagram of the B-B cross section of the precipitation zone of specific embodiment 1 of the present invention.

Figure 5 is a schematic diagram of the B-B cross-section of the precipitation zone of specific embodiment 2 of the present invention.

Among them, 1. trough body; 2. sand layer; 3. supporting layer; 4. filling layer; 5. sludge layer; 6. mud-water separation layer; 7. air collecting layer; 8. soil layer; 9. air collecting pipe; 10. mud discharge branch pipe; 11. vacuum device; 12. water pump; 13. mud discharge branch pipe valve; 14. air pipe; 15. blower; 16. air pipe valve; 17. anti-seepage membrane; 18. water inlet; 19. water outlet; 20. anaerobic zone; 21. aerobic zone; 22. sedimentation zone; 23. sewage return pipe; 24. mud discharge well; 25. mud discharge main pipe.

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.

Embodiment 1:

As shown in Figures 1, 2, and 4, this embodiment includes a tank body 1, which is excavated below the ground and is covered with an impermeable membrane 17 on all sides and at the bottom. The tank body 1 is composed of an anaerobic zone 20, an aerobic zone 21, and a sedimentation zone 22 from left to right. The anaerobic zone 20 and the aerobic zone 21 are filled with a sand layer 2, a supporting layer 3, a filler layer 4, an air collection layer 7, and a soil layer 8 from bottom to top. The sedimentation zone 22 is filled with a sand layer 2, a sludge layer 5, a mud-water separation layer 6, an air collection layer 7, and a soil layer 8 from bottom to top. The water inlet 18 and the water outlet 19 are respectively located on both sides of the tank body 1. The anaerobic zone 20, the aerobic zone 21, and the sedimentation zone 22 are all equipped with a plurality of independently controlled air pipes 14 and mud discharge branches 10, wherein the air outlet of the air pipe 14 is located at the bottom of the filler layer 4 or the bottom of the sludge layer 5, and the other end of the air pipe 14 is connected to an external blower 15. The mud discharge branch pipe 10 is located at the supporting layer 3 or the packing layer 4 below the liquid surface, and a plurality of mud discharge holes are opened on the pipe wall. The mud discharge branch pipe 10 is connected to the vacuum device 11, i.e., the water ejector, and bends upward and extends out of the tank body 1. The highest liquid level of the tank body 1 is located at the bottom of the gas collecting layer 7. The tank body 1 is provided with a sewage return pipe 23, one end of which is located at the end of the aerobic zone 21 in the packing layer 4, and the other end is connected to the water inlet 18.

Embodiment 2:

As shown in Figures 1, 3 and 5, this embodiment includes a tank body 1, which is excavated below the ground and is covered with an impermeable membrane 17 on the surroundings and bottom. The tank body 1 is divided into an anaerobic zone 20, an aerobic zone 21 and a sedimentation zone 22 from left to right. The anaerobic zone 20 and the aerobic zone 21 are filled with a sand layer 2, a supporting layer 3, a filler layer 4, an air collection layer 7 and a soil layer 8 from bottom to top. The sedimentation zone 22 is filled with a sand layer 2, a sludge layer 5, a mud-water separation layer 6, an air collection layer 7 and a soil layer 8 from bottom to top. The water inlet 18 and the water outlet 19 are respectively located on both sides of the tank body 1. The anaerobic zone 20, the aerobic zone 21 and the sedimentation zone 22 are all equipped with a plurality of independently controlled air pipes 14 and mud discharge branches 10, wherein the air outlet of the air pipe 14 is located at the bottom of the filler layer 4 or the bottom of the sludge layer 5, and the other end of the air pipe 14 is connected to an external blower 15. The mud discharge branch pipe 10 is located in the mud layer 5 or mud-water separation layer 6 below the liquid surface, and a plurality of mud discharge holes are opened on the pipe wall. The mud discharge branch pipe 10 is directly connected to the mud discharge branch pipe valve 13 and extends out of the tank body 1. The highest liquid level of the tank body 1 is located at the bottom of the gas collecting layer 7. The tank body 1 is provided with a sewage return pipe 23, one end of which is located at the end of the aerobic zone 21 in the packing layer 4, and the other end is connected to the water inlet 18.

The specific process of sewage treatment by the device of the present invention is as follows:

The sewage to be treated enters the sewage land treatment system, and passes through the anaerobic zone 20, the aerobic zone 21 and the sedimentation zone 22 from left to right. Each zone is divided into multiple working intervals, and each interval is divided into two states: working and backwashing. In the working state, the air pipe valves 16 of the anaerobic zone and the sedimentation zone are closed, and only the aerobic zone is aerated and oxygenated. The sewage is subjected to anaerobic biological filtration treatment in the anaerobic zone 20 to degrade the organic matter in the sewage, and at the same time, the nitrate nitrogen and nitrite nitrogen in the sewage returned from the aerobic zone 21 are denitrified. Subsequently, the sewage enters the aerobic zone 21 for aerobic biological filtration treatment. The microorganisms attached to the filler layer 4 perform aerobic reactions in this layer, mainly oxidizing and decomposing nitrogen-containing compounds and organic matter. At the end of the aerobic zone 21, part of the sewage is returned to the anaerobic zone 20 through the sewage return pipe 23 under the control of the water pump 12. When the sewage enters the sedimentation zone 22 on the far right, the detached biofilm in the sewage is intercepted and removed through the filtration and sedimentation action of this zone, and the treated water is finally discharged from the sewage land treatment system through the outlet 19. The waste gas and compressed air generated during operation are collected and discharged into the sewage land treatment system through the gas collecting pipe 9 in the gas collecting layer 7, and the gas is discharged into the atmosphere directly or after being collected and centrally treated. During the filtration process of the sewage through the system, sludge and biofilm are continuously accumulated in the packing layer 4, sludge layer 5 and mud-water separation layer 6.

During operation, when the amount of sludge accumulated in the system reaches a certain amount, an interval backwashing operation is performed. Start the blower 15, adjust the air flow rate of the backwashing section to the backwashing air flow rate, and perform air-water combined backwashing on one or several intervals of the anaerobic zone 20, aerobic zone 21 or sedimentation zone 22 of the system. It is only necessary to open the vacuum device 11 or the mud discharge branch pipe valve 13, and use the filter material gap water in the surrounding non-flushing area to perform air-water combined backwashing on the packing layer 4, the sludge layer 5 and the mud-water separation layer 6. There is no need to introduce external clean water, which saves water. The use of air-water combined backwashing can improve the backwashing effect, not only to solve the blockage problem of the packing layer 4, the sludge layer 5 and the mud-water separation layer 6, but also to renew the biofilm of the packing layer 4, restore the microorganisms' ability to degrade and purify pollutants in sewage, and improve the effluent water quality. There is no need to close the water inlet 18 and the water outlet 19 during the backwashing process. If a vacuum device 11 is installed on the outlet of the mud discharge branch pipe 10, turn on the vacuum device 11, and negative pressure is generated in the pipe. The sludge enters the mud discharge branch pipe 10 through the mud discharge hole, and is discharged to the mud discharge well 24 under the action of siphon, and then is discharged into the sludge recovery tank through the mud discharge main pipe 25. If a valve is installed on the outlet of the mud discharge branch pipe 10, open the mud discharge branch pipe valve 13, and the sludge enters the mud discharge branch pipe 10 through the mud discharge hole, and is discharged into the sludge recovery tank through the mud discharge main pipe 25. Water or air can be used alone for backwashing.

When the backwashing of this interval is finished, the mud discharge branch pipe valve 13 is closed or the mud discharge siphon is destroyed to stop the mud discharge. At the same time, if the backwashing interval is in the anaerobic zone 20 or the sedimentation zone 22, the air pipe valve 16 is closed. If the backwashing interval is in the aerobic zone 21, the air flow rate is reduced to the amount of air required for oxygen supply. The backwashing process of this interval ends, and the biological filtration or sedimentation filtration working mode is entered. The system performs backwashing of the next interval to complete the sequential interval backwashing operation.

The above is a preferred embodiment of the present invention, and is not intended to limit the scope of protection of the invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the scope of protection of the present invention.

Claims (6)

1. A high-efficiency backwashing artificial ecological sewage land treatment system, comprising a tank body (1), wherein the tank body (1) is paved with an impermeable membrane (17) around and at the bottom, and the tank body (1) comprises, from left to right, an anaerobic zone (20), an aerobic zone (21), and a sedimentation zone (22); the anaerobic zone (20) and the aerobic zone (21) are filled with a sand layer (2), a supporting layer (3), a filler layer (4), an air collection layer (7), and a soil layer (8) in sequence from bottom to top; the sedimentation zone (22) is filled with a sand layer (2), a sludge layer (5), a sludge-water separation layer (6), an air collection layer (7), and a soil layer (8) in sequence from bottom to top; a water inlet (18) and a water outlet (19) are respectively provided on both sides of the tank body (1); the tank body (1) is further provided with an air pipe (14) and a sludge discharge branch pipe (10); the air outlet of the air pipe (14) is located at the bottom of the filler layer (4) or the bottom of the sludge layer (5) The mud discharge branch pipe (10) is located in a supporting layer (3) or a packing layer (4), a sludge layer (5) or a mud-water separation layer (6) below the liquid level of the tank body (1); a vacuum device (11) or a mud discharge branch pipe valve (13) is installed on the water outlet of the mud discharge branch pipe (10); the anaerobic zone (20), the aerobic zone (21) and the sedimentation zone (22) are all provided with a plurality of independently controlled air pipes (14) and mud discharge branch pipes (10); a plurality of mud discharge holes are opened on the pipe wall of the mud discharge branch pipe (10); the vacuum device (11) or the mud discharge branch pipe valve (13) is opened, and the packing layer (4), the sludge layer (5) and the mud-water separation layer (6) are backwashed by using air and the filter material gap water in the non-flushing area around the system, and the head difference inside and outside the filter tank is directly used as the backwashing power, without the need for a backwashing water pump, a separate flushing pipe and a valve, and the sludge is discharged from the sewage land treatment system through the mud discharge branch pipe (10). 2. The high-efficiency backwashing artificial ecological sewage land treatment system according to claim 1 is characterized in that the tank body (1) is provided with a sewage return pipe (23), one end of which is located at the end of the aerobic zone (21) in the packing layer (4), and the other end is connected to the water inlet (18). 3. The high-efficiency backwashing artificial ecological sewage land treatment system according to claim 1 is characterized in that the highest liquid level of the tank body (1) is located at the bottom of the gas collection layer (7). 4. The high-efficiency backwashing artificial ecological sewage land treatment system according to claim 1 is characterized in that one end of the air pipe (14) is connected to an external blower (15). 5. The high-efficiency backwashing artificial ecological sewage land treatment system according to claim 1 is characterized in that the supporting layer (3), the filler layer (4), the sludge layer (5), the mud-water separation layer (6), and the gas collection layer (7) are all filled with fillers. 6. The high-efficiency backwashing artificial ecological sewage land treatment system according to claim 5 is characterized in that the filler is gravel or other granular fillers.