Sewage treatment device and food processing wastewater treatment method

Abstract

The invention discloses a sewage treatment device and a food processing wastewater treatment method, the sewage treatment device comprises an anaerobic zone, an anoxic zone and an aerobic zone, the aerobic zone is internally provided with a first interception net, and the first interception net is arranged around a water outlet pipe of the aerobic zone; a reflux tank is arranged in the aerobic zone, the reflux tank is communicated with the aerobic zone through a lifting device, and the reflux tank and the water outlet pipe are respectively arranged on two sides of the first intercepting net; a second intercepting net, a first communicating pipe and a second communicating pipe are arranged on the side wall of the reflux tank, the second intercepting net is arranged at the first communicating pipe, and the second communicating pipe is higher than the first communicating pipe; the reflux tank is communicated with the anoxic zone through a first communicating pipe, and the reflux tank is communicated with the anaerobic zone through a second communicating pipe; a carrier is arranged in the anaerobic zone, and stirring devices are arranged in the anaerobic zone, the anoxic zone and the reflux tank. The sewage treatment device solves the technical problem that carriers are stacked at the tail end in the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing wastewater treatment, and in particular relates to a sewage treatment device and a method for treating food processing wastewater. Background Art

[0002] The food industry is extremely complex, including production processes such as sugar making, brewing, meat, and dairy processing. The wastewater discharged contains organic matter, has strong oxygen consumption, and contains a large amount of suspended matter. The wastewater discharged from animal food processing also contains animal excrement, blood, fur, grease, etc., and may contain pathogens. Therefore, the oxygen consumption is very high, and the pollution is much higher than that of wastewater discharged from plant food processing.

[0003] The existing treatment process generally adopts enhanced biochemical process treatment after pretreatment to remove pollutants in sewage. The enhanced biochemical process generally includes anaerobic, anoxic, aerobic and sedimentation processes. In actual application, due to the impact of influent pollutants, it is easy to cause the death of microorganisms in the system, and a large amount of sludge overflows from the sedimentation tank, resulting in substandard sewage treatment.

[0004] At present, carriers can also be used to treat food processing wastewater, but generally interception nets are added at the end of the treatment process, and carriers are only added to aerobic tanks. If carriers are added to anaerobic and anoxic tanks, the interception nets in the anaerobic and anoxic tanks will also be blocked. When blockage occurs, adding aeration and cleaning will break the anaerobic and anoxic oxygen-free environment and destroy the functionality of the tank. Summary of the invention

[0005] In view of the current technical problems, the present invention aims to provide a sewage treatment device and a method for treating food processing wastewater. The sewage treatment device can solve the technical problem of carrier accumulation at the end in the prior art.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A sewage treatment device comprises an anaerobic zone, an anoxic zone and an aerobic zone, wherein a first interception net is arranged in the aerobic zone and the first interception net is arranged around a water outlet pipe of the aerobic zone; the structural features are as follows: a reflow trough is arranged in the aerobic zone, the reflow trough is connected with the aerobic zone through a lifting device, and the reflow trough and the water outlet pipe of the aerobic zone are arranged on both sides of the first interception net respectively; a second interception net, a first connecting pipe and a second connecting pipe are arranged on the side wall of the reflow trough, the second interception net is arranged at the first connecting pipe, and the height of the second connecting pipe is higher than that of the first connecting pipe; the reflow trough is connected with the anoxic zone through the first connecting pipe, and the reflow trough is connected with the anaerobic zone through the second connecting pipe; a carrier is arranged in the anaerobic zone, and a stirring device is arranged in the anaerobic zone, the anoxic zone and the reflow trough.

[0008] When the sewage treatment device of the present invention is used, the sewage first enters the anaerobic zone. After being treated by the microorganisms on the carrier in the anaerobic zone, the carrier enters the anoxic zone with the sewage for denitrification treatment. The sewage and the carrier then flow into the aerobic zone for treatment, and the first interception net intercepts the carrier and then discharges the water from the outlet pipe. The sewage is purified during the flow process. Part of the sewage and the carrier in the aerobic zone are lifted into the reflow tank by the lifting device. By setting a stirring device in the reflow tank, the carrier in the reflow tank is treated in a flowing state. Due to the interception effect of the second interception net on the carrier, the sewage in the reflow tank flows back to the anoxic zone through the first connecting pipe to ensure the denitrification reaction, and the carrier returns to the anaerobic zone through the second connecting pipe, thereby solving the technical problem of the accumulation of the carrier at the end and ensuring the circulation of the carrier.

[0009] Preferably, the lifting device includes an inverted U-shaped lifting pipe, a motor, a rotating shaft installed at the power output end of the motor, and a spiral blade arranged on the rotating shaft, and the spiral blade extends along the length direction of the rotating shaft; one end of the lifting pipe faces the reflux tank, and the other end faces the aerobic zone; the rotating shaft is arranged in the lifting pipe, and the lifting end of the rotating shaft is arranged in the aerobic zone, and a gap is arranged between the spiral blade and the inner wall of the lifting pipe. Driven by the motor, the rotating shaft drives the spiral blade to rotate, and at the same time, the carrier and sewage at the pipe mouth of the lifting pipe in the aerobic zone are lifted upward to the reflux tank. By adjusting the motor speed, the rotation speed of the rotating shaft can be changed. When the speed is slow, the carrier can be lifted into the reflux tank, and the sewage flows out through the gap between the spiral blade and the inner wall of the lifting pipe; when the speed is fast, the carrier and the sewage can be lifted into the reflux tank together.

[0010] Preferably, an air brush device is provided below the end of the lifting pipe facing the aerobic zone, one end of the air brush device is connected to the first blower, and the other end faces the end of the lifting pipe, and the air brush device can transmit the gas of the first blower to the lifting pipe. When blockage occurs in the lifting pipe, the first blower is turned on to inflate the air brush device, and the gas is transmitted to the lifting pipe through the air brush device. The gas impacts the blocked part in the lifting pipe during the rising process, thereby clearing the blockage.

[0011] Preferably, the air brush device comprises a vertically arranged gas collecting cylinder, the top of which is open; the bottom of the gas collecting cylinder is connected to the first blower through an air inlet pipe, a rotatably connected cover plate is provided on the top of the gas collecting cylinder, a plurality of through holes are provided on the cover plate, and at least one elastic element is provided between the cover plate and the top of the gas collecting cylinder. The elastic element can be a spring, and when the sewage treatment device is operating normally, a small amount of gas is blown into the gas collecting cylinder through the first blower, and the gas flows upward into the lifting pipe through the through holes on the cover plate, which can assist the spiral blades in lifting the carrier together; and when the lifting device needs to increase the lifting amount or the lifting pipe is blocked, the air supply can be increased, and when the gas pressure in the gas collecting cylinder reaches a certain level, the cover plate will be opened outward, and the gas will instantly rush out and enter the lifting pipe, and the lifting pipe will be strongly flushed.

[0012] Preferably, a first liquid level gauge is provided in the anaerobic zone, and a second liquid level gauge is provided in the aerobic zone, and the second liquid level gauge is provided at the outlet pipe. By providing the first liquid level gauge and the second liquid level gauge, the liquid level difference in the anaerobic zone and the aerobic zone can be monitored. If the liquid level difference increases, it means that the first interception net is blocked by the carrier, and the lifting amount of the lifting device can be increased to increase the amount of carrier recovery.

[0013] Preferably, the first connecting pipe is provided with a first valve, the second connecting pipe is provided with a second valve, and the stirring device, the first liquid level gauge, the second liquid level gauge, the lifting device, the first valve, the second valve, and the aeration device in the aerobic zone are all electrically connected to the control system. By equipping the control system, the stirring device frequency, the opening of the first valve and the second valve, the air supply of the aeration device, the lifting amount of the lifting device, etc. are controlled according to instruments such as the liquid level gauge, and related problems can be automatically solved without manual operation, thereby ensuring the stability of the system and the timeliness of the processing.

[0014] Preferably, the cross section of the aerobic zone is a rectangle, and the ratio of the width to the length of the rectangle is greater than or equal to 1: 5. By setting the width-to-length ratio of the aerobic zone, the water flow rate in the aerobic zone can be reduced to prevent the carrier from flowing too fast with the water and accumulating at the end.

[0015] Specifically, the reflow groove is arranged on the side wall of the aerobic zone, and the side of the reflow groove provided with the first connecting pipe is arranged adjacent to the anoxic zone, and the side of the reflow groove provided with the second connecting pipe is arranged adjacent to the anaerobic zone.

[0016] Based on the same inventive concept, the present application also provides a method for treating food processing wastewater, which is treated by the sewage treatment device as described above, and specifically comprises the following steps:

[0017] S1. After the wastewater enters the anaerobic zone for treatment, the wastewater carries the carrier into the anoxic zone for denitrification treatment;

[0018] S2, the wastewater and carrier then enter the aerobic zone, and the wastewater treated in the aerobic zone is discharged through the outlet pipe;

[0019] S3. Part of the wastewater and carrier in the aerobic tank is lifted into the reflow tank through the lifting device. The wastewater in the reflow tank flows back to the anoxic zone through the first connecting pipe, and the carrier in the reflow tank returns to the anaerobic zone through the second connecting pipe.

[0020] Food processing wastewater has the characteristics of high pollutant concentration and complex pollutant composition. The wastewater first enters the anaerobic tank, and the carrier adsorbs the insoluble impurities in the wastewater. Some granular impurities will adhere to the surface of the carrier, and the carrier removes the pollutants from the wastewater for the first time. Since the carrier is in an anaerobic environment, the microorganisms on the carrier can decompose the soluble organic matter, and the anaerobic bacteria on the carrier convert the large molecular soluble organic matter into small molecular organic matter, which is easier to be absorbed by subsequent reactions. Then the carrier enters the anoxic tank with the wastewater. The denitrifying bacteria attached to the carrier use the premise that the soluble organic matter and the insoluble organic matter jointly provide carbon sources, so that a large amount of nitrate in the anoxic tank is converted into nitrogen and released into the air to achieve the purpose of denitrification. The sewage and the carrier then flow into the aerobic tank, and the aerobic bacteria on the carrier begin to decompose ammonia nitrogen and the remaining soluble and insoluble organic matter. In addition, common carrier materials are cylindrical structures made of polymer materials such as PE or PP, with a diameter of 10 to 30 cm, porous inside, large specific surface area, hard texture, not easy to decompose, and generally maintained at a service life of more than 20 years. Therefore, the microorganisms on the carrier will not be easily discharged, the microbial era cycle is long, and more protozoa and metazoa will appear. Protozoa, metazoa and bacteria form a complete biological chain system, that is, protozoa feed on bacteria and organic matter, and metazoa feed on protozoa and organic matter. The phosphorus element in the wastewater will be enriched in the metazoan body during this process. When the metazoan finally dies, it falls off from the carrier to form insoluble sludge, which is discharged regularly. The method of the present invention is different from the anaerobic phosphorus release, aerobic phosphorus absorption, and sludge removal principle of the conventional A2O activated sludge method. The phosphorus removal method of the present invention utilizes the biological chain to remove phosphorus, with a smaller amount of sludge discharge, lower sludge disposal fee, and more obvious effect. The method for treating food processing wastewater of the present invention utilizes the continuous circulation of the carrier in the anaerobic tank, the anoxic tank and the aerobic tank, thereby completely removing pollutants such as organic matter, nitrogen and phosphorus.

[0021] Preferably, the dissolved oxygen in the aerobic zone is 1-4 mg / L, the air-water volume ratio is 5-15:1; the density of the carrier is 1-1.01 g / cm 3 , the carrier filling rate is 10 to 40%.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The sewage treatment device of the present invention solves the accumulation of the terminal carrier by setting a return trough, a lifting device and a second interception net, and separates the sewage from the carrier, ensuring that the sewage returns to the anoxic tank and the carrier returns to the aerobic tank, so that the carrier circulates during the treatment process.

[0024] 2. The sewage treatment device of the present invention assists the fluidity of the carrier in the lifting device by providing an air brush device, and can also play an air brush cleaning role on the lifting device.

[0025] 3. The sewage treatment device of the present invention is equipped with a control system, which does not require human control, thereby ensuring stable and safe operation of the device.

[0026] 4. The food processing wastewater treatment method of the present invention increases the amount and activity of all organisms in the wastewater and improves the impact resistance of food wastewater treatment by allowing the carrier to flow in the process flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the sewage treatment device of the present invention;

[0028] Figure 2 yes Figure 1 Schematic diagram of the structure of the middle reflux tank;

[0029] Figure 3 yes Figure 2 Schematic diagram of the structure of the middle lifting device;

[0030] Figure 4 yes Figure 2 Schematic diagram of the air brush device structure.

[0031] In the figure

[0032] 1-tank body, 2-water inlet pipe, 3-first flow hole, 4-control system, 5-first liquid level gauge, 6-stirring device, 7-second valve, 8-first valve, 9-second interception net, 10-lifting device, 10-1-lifting pipe, 10-2-motor, 10-3-rotating shaft, 10-4-spiral blade, 11-second liquid level gauge, 12-first interception net, 13-water outlet pipe, 14-aeration device, 14-1-aeration plate, 14-2-second blower, 15-carrier, 16-first partition, 17-anaerobic zone, 18-anoxic zone, 19-aerobic zone, 20-reflow trough, 21-air brush device, 21-1 air collecting cylinder, 21-2-air inlet pipe, 21-3-cover plate, 21-4-through hole, 21-5-elastic element, 22-second flow hole, 23-first connecting pipe, 24-second connecting pipe, 25-second partition, 26-first blower. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear in the following, they only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure.

[0034] like Figure 1 As shown, a sewage treatment device of this embodiment includes a tank body 1 and a control system 4, and the ratio of the width to the length of the tank body 1 is 1:5. A first partition 16 is provided in the tank body 1 along the length direction, and the first partition 16 and the right side wall of the tank body 1 enclose an aerobic zone 19. A second partition 25 is provided in the width direction in the area enclosed by the first partition 16 and the left side wall of the tank body 1, so as to separate the left side area of ​​the tank body 1 into an anaerobic zone 17 and an anoxic zone 18. A first flow hole 3 is provided on the second partition 25, and the anaerobic zone 17 and the anoxic zone 18 are connected through the first flow hole 3. A second flow hole 22 is provided on the first partition 16, and the anoxic zone 18 and the aerobic zone 19 are connected through the second flow hole 22, and the first flow hole 3 and the second flow hole 22 are respectively arranged at the diagonal positions of the anoxic zone 18. An inlet pipe 2 is provided on the side wall of the anaerobic zone 17, and an outlet pipe 13 is provided on the side wall of the aerobic zone 19. A first liquid level gauge 5 is provided in the anaerobic zone 17, and a second liquid level gauge 11 is provided in the aerobic zone 19, and the second liquid level gauge 11 is arranged at the outlet pipe 13. A first interception net 12 is provided in the aerobic zone 19 along the width direction, and the first interception net 12 is arranged close to the outlet pipe 13. An aeration device 14 and a reflow trough 20 are provided in the aerobic zone 19, and the reflow trough 20 is arranged on the inner side wall of the aerobic zone 19. The reflow trough 20 is connected to the aerobic zone 19 through the lifting device 10, and the reflow trough 20 and the outlet pipe 13 are respectively arranged on both sides of the first interception net 12. The aeration device 14 includes an aeration plate 14-1 arranged in the aerobic zone 19 and a second blower 14-2 connected to the aeration plate 14-1. A carrier 15 is provided in the anaerobic zone 17, and a stirring device 6 is provided in the anaerobic zone 17, the anoxic zone 18 and the reflow trough 20. The carrier 15 is a cylindrical structure made of polymer materials such as PE or PP, with a diameter of 10 to 30 cm. The carrier 15 is porous inside, has a large specific surface area, is hard, is not easy to decompose, and has a long service life, generally more than 20 years. The stirring power of the stirring device 6 used in the anaerobic zone 17 and the anoxic zone 18 is controlled to be more than 5W per cubic meter, but not more than 15W.

[0035] like Figure 1 and Figure 2As shown, a second interception net 9, a first connecting pipe 23, and a second connecting pipe 24 are provided on the side wall of the reflow trough 20. The second interception net 9 is arranged at the first connecting pipe 23, and the height of the second connecting pipe 24 is higher than that of the first connecting pipe 23. One side of the reflow trough 20 provided with the first connecting pipe 23 is arranged adjacent to the anoxic zone 18, and the reflow trough 20 and the anoxic zone 18 are connected through the first connecting pipe 23, and a first valve 8 is provided on the first connecting pipe 23. One side of the reflow trough 20 provided with the second connecting pipe 24 is arranged adjacent to the anaerobic zone 17, and the reflow trough 20 and the anaerobic zone 17 are connected through the second connecting pipe 24, and a second valve 7 is provided on the second connecting pipe 24. As shown Figure 2 and Figure 3 As shown, the lifting device 10 includes an inverted U-shaped lifting pipe 10-1, a motor 10-2, a rotating shaft 10-3 installed at the power output end of the motor 10-2, and a spiral blade 10-4 arranged on the rotating shaft 10-3, and the spiral blade 10-4 extends along the length direction of the rotating shaft 10-3. One end of the lifting pipe 10-1 faces the aerobic zone 19, and the other end faces the reflow tank 20. The rotating shaft 10-3 is arranged in the lifting pipe 10-1, and the lifting end of the rotating shaft 10-3 is arranged in the aerobic zone 19, and a gap is arranged between the spiral blade 10-4 and the inner wall of the lifting pipe 10-1. Figure 2 and Figure 4 As shown, an air brush device 21 is provided below the end of the lifting pipe 10-1 facing the aerobic zone 19, and the air brush device 21 includes a vertically arranged gas collecting cylinder 21-1, and the top of the gas collecting cylinder 21-1 is open. The bottom of the gas collecting cylinder 21-1 is connected to the first blower 26 through the air inlet pipe 21-2, and a rotatably connected cover plate 21-3 is provided on the top of the gas collecting cylinder 21-1. Four through holes 21-4 are provided on the cover plate 21-3, and two elastic elements 21-5 are provided between the cover plate 21-3 and the top of the gas collecting cylinder 21-1. The elastic elements 21-5 are springs. The stirring device 6, the first liquid level gauge 5, the second liquid level gauge 11, the motor 10-2, the first valve 8, the second valve 7, the second blower 14-2 and the first blower 26 are all electrically connected to the control system 4.

[0036] This embodiment also provides a method for treating food processing wastewater, which uses the sewage treatment device as described above for treatment, and specifically includes the following steps:

[0037] S1, after the wastewater enters the anaerobic zone 17 for treatment, the wastewater carries the carrier 15 into the anoxic zone 18 for denitrification treatment;

[0038] S2, the wastewater and carrier 15 then enter the aerobic zone 19, and the wastewater treated in the aerobic zone 19 is discharged through the outlet pipe 13;

[0039] S3. Part of the wastewater and the carrier 15 in the aerobic tank 19 are lifted into the reflow tank 20 by the lifting device 10. The wastewater in the reflow tank 20 flows back to the anoxic zone 18 through the first connecting pipe 23. The carrier 15 in the reflow tank 20 returns to the anaerobic zone 17 through the second connecting pipe 24.

[0040] The dissolved oxygen in the aerobic zone 19 is 1-4 mg / L, and the air-water volume ratio is 5-15:1. The density of the carrier 15 is 1-1.01 g / cm 3 The filling rate of the carrier 15 is 10 to 40%.

[0041] Food processing wastewater has the characteristics of high pollutant concentration and complex pollutant composition, among which organic matter and nitrogen and phosphorus concentration are relatively high. Food processing wastewater first enters the anaerobic zone 17, and the carrier 15 adsorbs the insoluble impurities in the sewage. Some granular impurities will adhere to the surface of the carrier 15, and the carrier 15 removes the first pollutant from the sewage. In addition, since the carrier 15 is in an anaerobic environment, the microorganisms on the carrier 15 can decompose the soluble organic matter in the sewage, and the anaerobic bacteria on the carrier 15 convert the macromolecular soluble organic matter into small molecular organic matter, which is easier to be absorbed by subsequent reactions. After the sewage is treated in the anaerobic zone 17, the carrier enters the anoxic zone 18 with the sewage through the first flow hole 3. The denitrifying bacteria attached to the carrier 15 convert a large amount of nitrate nitrogen in the sewage into nitrogen gas and release it into the air under the premise that the soluble organic matter and the insoluble organic matter jointly provide carbon sources, thereby achieving the purpose of denitrification. Subsequently, the sewage and the carrier flow into the aerobic zone 19 through the second flow hole 22. In the aerobic zone 19, the aeration plate 14-1 arranged at the bottom provides sufficient dissolved oxygen for the carrier 15. Generally, the dissolved oxygen is controlled at 1-4 mg / L, and the gas-water ratio is controlled at 5-15:1. In the aerobic pool, the aerobic bacteria on the carrier 15 begin to decompose ammonia nitrogen, and the remaining soluble and insoluble organic matter. When the aerobic zone 19 controls the dissolved oxygen below 2 mg / L, the inner layer of the carrier 15 will present an anaerobic and anoxic environment, while the surface layer of the carrier 15 will present an aerobic environment. Therefore, on the same carrier 15, under the condition of low dissolved oxygen in the aerobic zone 19, a single carrier 15 forms a separate biochemical system, which can effectively and collaboratively remove organic matter, nitrogen and phosphorus, etc. Since the first interception net 12 and the lifting device 10 are arranged at the end of the aerobic zone 19, the carrier 15 will not be lost. Driven by the motor 10-2, the rotating shaft 10-3 drives the spiral blade 10-4 to rotate, and at the same time, the carrier 15 and sewage at the pipe mouth of the lifting pipe 10-1 in the aerobic zone 19 are lifted upward to the reflow tank 20. The rotation speed of the rotating shaft 10-3 can be changed by adjusting the motor 10-2. When the speed is slow, the carrier 15 can be lifted into the reflow tank 20, and the sewage flows out through the gap between the spiral blade 10-4 and the inner wall of the lifting pipe 10-1; when the speed is fast, the carrier 15 and the sewage can be lifted into the reflow tank 20 together. Due to the interception effect of the second interception net 9 on the carrier 15, the sewage in the reflow tank 20 flows back to the anoxic zone 18 through the first connecting pipe 23 to ensure the denitrification reaction, and the carrier 15 returns to the anaerobic zone 17 through the second connecting pipe 24, thereby ensuring the circulation of the carrier 15. When the sewage treatment device operates normally, a small amount of gas is blown into the gas collecting cylinder 21-1 through the first blower 26, and the gas flows upward into the lifting pipe 10-1 through the through hole 21-4 on the cover plate 21-3, which can assist the spiral blade 10-4 to lift the carrier.When the lifting device 10 needs to increase the lifting amount or the lifting pipe 10-1 is blocked, the gas supply can be increased. When the gas pressure in the gas collecting cylinder 21-1 reaches a certain level, the cover plate 21-3 will be opened outward, and the gas will instantly rush out and enter the lifting pipe 10-1, strongly flushing the lifting pipe 10-1, thereby clearing the blockage.

[0042] Since the microorganisms on the carrier 15 will not be easily discharged, the microorganism era cycle is long, and more protozoa and metazoa will appear. Protozoa, metazoa and bacteria form a complete biological chain system, that is, protozoa feed on bacteria and organic matter, and metazoa feed on protozoa and organic matter. Phosphorus will be enriched in metazoa in this process. When the metazoa finally die, they will fall off from the carrier to form insoluble sludge, which will be discharged regularly. Therefore, the treatment method of food processing wastewater in this embodiment is completely different from the anaerobic phosphorus release, aerobic phosphorus absorption and sludge phosphorus removal principles of the conventional A2O activated sludge method. The phosphorus removal in this embodiment is phosphorus removal through the biological chain on the carrier 15, with a smaller amount of sludge discharge, lower sludge disposal fees, and more obvious effects. Therefore, the continuous circulation of the carrier 15 in the anaerobic zone 17, the anoxic zone 18, and the aerobic zone 19 is used to comprehensively remove pollutants such as organic matter, nitrogen and phosphorus, which is particularly suitable for the application scenario of food processing wastewater.

[0043] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the invention, and are not used to limit the scope of the invention. After reading the present invention, various equivalent forms of modifications to the embodiments by those skilled in the art fall within the scope defined by the claims attached to the present invention.

Claims

1. A sewage treatment device, comprising an anaerobic zone (17), an anoxic zone (18) and an aerobic zone (19), wherein a first interception net (12) is provided in the aerobic zone (19), and the first interception net (12) is arranged around a water outlet pipe (13) of the aerobic zone (19); characterized in that: A reflow trough (20) is provided in the aerobic zone (19), the reflow trough (20) is connected to the aerobic zone (19) via a lifting device (10), and the reflow trough (20) and the water outlet pipe (13) are respectively arranged on both sides of the first interception net (12); A second interception net (9), a first connecting pipe (23) and a second connecting pipe (24) are provided on the side wall of the reflux groove (20); the second interception net (9) is arranged at the first connecting pipe (23), and the height of the second connecting pipe (24) is higher than that of the first connecting pipe (23); The reflow trough (20) is connected to the anoxic zone (18) via a first connecting pipe (23), and the reflow trough (20) is connected to the anaerobic zone (17) via a second connecting pipe (24); The anaerobic zone (17) is provided with a carrier (15), and the anaerobic zone (17), the anoxic zone (18) and the reflow tank (20) are all provided with a stirring device (6).

2. The sewage treatment device according to claim 1, characterized in that: The lifting device (10) comprises an inverted U-shaped lifting pipe (10-1), a motor (10-2), a rotating shaft (10-3) mounted on the power output end of the motor (10-2), and a spiral blade (10-4) arranged on the rotating shaft (10-3), wherein the spiral blade (10-4) extends along the length direction of the rotating shaft (10-3); one end of the lifting pipe (10-1) faces the reflux groove (20), and the other end faces the aerobic zone (19); the rotating shaft (10-3) is arranged in the lifting pipe (10-1), and the lifting end of the rotating shaft (10-3) is arranged in the aerobic zone (19), and a gap is arranged between the spiral blade (10-4) and the inner wall of the lifting pipe (10-1).

3. The sewage treatment device according to claim 2, characterized in that: An air brush device (21) is provided below the end of the lifting pipe (10-1) facing the aerobic zone (19); one end of the air brush device (21) is connected to the first blower (26), and the other end faces the end of the lifting pipe (10-1); the air brush device (21) can transmit the gas from the first blower (26) to the inside of the lifting pipe (10-1).

4. The sewage treatment device according to claim 3, characterized in that: The air brush device (21) comprises a vertically arranged air collecting cylinder (21-1), the top of which is open; the bottom of the air collecting cylinder (21-1) is connected to a first blower (26) via an air inlet pipe (21-2); a rotatably connected cover plate (21-3) is provided on the top of the air collecting cylinder (21-1); a plurality of through holes (21-4) are provided on the cover plate (21-3); and at least one elastic element (21-5) is provided between the cover plate (21-3) and the top of the air collecting cylinder (21-1).

5. The sewage treatment device according to claim 1, characterized in that: A first liquid level meter (5) is provided in the anaerobic zone (17), and a second liquid level meter (11) is provided in the aerobic zone (19). The second liquid level meter (11) is arranged at the outlet pipe (13).

6. The sewage treatment device according to claim 5, characterized in that: The first connecting pipe (23) is provided with a first valve (8), the second connecting pipe (24) is provided with a second valve (7), and the stirring device (6), the first liquid level gauge (5), the second liquid level gauge (11), the lifting device (10), the first valve (8), the second valve (7), and the aeration device (14) in the aerobic zone (19) are all electrically connected to the control system (4).

7. The sewage treatment device according to any one of claims 1 to 6, characterized in that: The cross section of the aerobic zone (19) is a rectangle, and the ratio of the width to the length of the rectangle is greater than or equal to 1:

5.

8. The sewage treatment device according to any one of claims 1 to 6, characterized in that: The reflow groove (20) is arranged on the side wall of the aerobic zone (19), and the side of the reflow groove (20) provided with the first connecting pipe (23) is arranged adjacent to the anoxic zone (18), and the side of the reflow groove (20) provided with the second connecting pipe (24) is arranged adjacent to the anaerobic zone (17).

9. A method for treating food processing wastewater, characterized in that: The sewage treatment device according to any one of claims 1 to 8 is used for treatment, which specifically comprises the following steps: S1, after the wastewater enters the anaerobic zone (17) for treatment, the wastewater carries the carrier (15) into the anoxic zone (18) for denitrification treatment; S2, wastewater and carrier (15) then enter the aerobic zone (19), and the wastewater treated in the aerobic zone (19) is discharged through the outlet pipe (13); S3. Part of the wastewater and the carrier (15) in the aerobic tank (19) are lifted into the reflow tank (20) through the lifting device (10), the wastewater in the reflow tank (20) is returned to the anoxic zone (18) through the first connecting pipe (23), and the carrier (15) in the reflow tank (20) is returned to the anaerobic zone (17) through the second connecting pipe (24).

10. The method for treating food processing wastewater according to claim 9, characterized in that: The dissolved oxygen in the aerobic zone (19) is 1-4 mg / L, the air-water volume ratio is 5-15:1; the density of the carrier (15) is 1-1.01 g / cm 3 The filling rate of the carrier (15) is 10 to 40%.

Images