Environment-friendly urea waste liquid treatment device

Abstract

The present application belongs to the technical field of urea waste liquid treatment, and particularly relates to an environment-friendly urea waste liquid treatment device, which comprises an exhaust device, an aerobic reactor and an anaerobic reactor, is connected with a water outlet pipe between the aerobic reactor and the anaerobic reactor, and is provided with a water inlet pump on the water outlet pipe; the aerobic reactor is provided with an internal circulation mechanism; the lower part of the aerobic reactor is internally provided with a first aeration head, and the lower part of the anaerobic reactor is internally provided with a second aeration head; the exhaust device is connected with an exhaust pipe, the first aeration head is connected with the exhaust pipe through a first connecting pipe, and the second aeration head is connected with the exhaust pipe through a second connecting pipe; the second connecting pipe is provided with an intermittent communication mechanism, and the second connecting pipe is installed with a valve. In the present application, the aerobic reactor and the anaerobic reactor are beneficial to the reproduction of different bacteria in two independent reactors, avoid the contradiction of different bacteria in sludge age and dissolved oxygen concentration, and improve the activity of each functional microorganism and the corresponding pollutant removal efficiency.

Description

Technical Field

[0001] This invention belongs to the field of urea waste liquid treatment technology, and specifically relates to an environmentally friendly urea waste liquid treatment device. Background Technology

[0002] Urea is the world's most widely used nitrogen fertilizer with the highest nitrogen content. It is also a crucial raw material for industries such as plastics, pharmaceuticals, food, and printing and dyeing, as well as for manufacturing chemical products like melamine, urea-formaldehyde resin, and explosives. Such a large production and consumption of urea inevitably generates substantial amounts of urea wastewater. This wastewater contains high levels of ammonia nitrogen, and direct discharge into water bodies will cause significant environmental damage. Ammonia nitrogen in water bodies leads to eutrophication, unpleasant odors, and even mass fish deaths.

[0003] Currently, the main methods for treating urea wastewater include thermal hydrolysis, chemical oxidation, urease hydrolysis, and biological treatment. Thermal hydrolysis and chemical oxidation consume large amounts of energy, resulting in high operating costs. They are only suitable for high-concentration urea wastewater, which is difficult for most small and medium-sized enterprises to afford. Although urease hydrolysis is effective at removing urea, its application in treating urea wastewater is not yet mature because the separation and purification technology of urease is still in the laboratory research stage. Biological treatment of urea wastewater is simple, has low operating costs, and provides good treatment results, offering economic and reliable advantages. The sequencing batch reactor (SBR) is a commonly used biological treatment method for urea wastewater. This method uses a bioreactor where both aerobic and anaerobic bacteria from the activated sludge react with the urea wastewater in the same bioreactor. Since aerobic and anaerobic bacteria require different environments, having them in the same bioreactor is not conducive to bacterial enrichment and can affect the efficiency of urea wastewater treatment to some extent. Summary of the Invention

[0004] The present invention aims to provide an environmentally friendly urea waste liquid treatment device to solve the problem that the accumulation of aerobic and anaerobic bacteria in the same bioreactor is not conducive to the enrichment of bacterial species and affects the treatment efficiency of urea waste liquid.

[0005] To achieve the above objectives, the present invention provides an environmentally friendly urea wastewater treatment device, comprising an exhaust device, an aerobic reactor, and an anaerobic reactor. An outlet pipe connects the aerobic reactor and the anaerobic reactor, and an inlet pump is installed on the outlet pipe. The aerobic reactor is equipped with an internal circulation mechanism for circulating the liquid within it. A first aeration head is located in the lower part of the aerobic reactor, and a second aeration head is located in the lower part of the anaerobic reactor. An exhaust pipe is connected to the exhaust device. A first connecting pipe connects the first aeration head to the exhaust pipe, and a second connecting pipe connects the second aeration head to the exhaust pipe. The second connecting pipe is equipped with an intermittent connection mechanism for intermittently connecting the pipe, and a valve is installed on the second connecting pipe.

[0006] The working principle of this scheme is as follows: both the aerobic and anaerobic reactors contain activated sludge. The activated sludge in the aerobic reactor mainly contains urea hydrolyzing bacteria and ammonia oxidizing bacteria, while the activated sludge in the anaerobic reactor mainly contains anaerobic ammonia oxidizing bacteria. When the treatment unit is initially put into operation, the aerobic reactor treats the urea wastewater first, while the anaerobic reactor remains inactive. After the aerobic reactor completes its treatment of the urea wastewater (when the urea removal rate reaches over 90%), the inlet pump is activated to transfer the treated urea wastewater (hereinafter referred to as the preliminary treated wastewater) from the aerobic reactor to the anaerobic reactor through the outlet pipe. The anaerobic reactor then further treats the preliminary treated wastewater. While the anaerobic reactor is further treating the preliminary treated wastewater, new urea wastewater is added to the aerobic reactor. The aerobic and anaerobic reactors can operate simultaneously. The operating process when the aerobic and anaerobic reactors operate simultaneously is as follows: New urea waste liquid is added to the aerobic reactor, and the internal circulation mechanism, exhaust device, intermittent connection mechanism, and valves are simultaneously opened. The internal circulation mechanism circulates the urea waste liquid in the aerobic reactor, while the exhaust device introduces air into the first and second connecting pipes through the exhaust pipe. The air enters the aerobic reactor through the first connecting pipe and the first aeration head for thorough aeration. The activated sludge bacteria in the aerobic reactor multiply fully and react with the urea waste liquid. Urea and oxygen are converted into NH3 and CO2 by urea hydrolyzing bacteria, and then converted into NO2 by ammonia oxidizing bacteria. - Due to the intermittent connection mechanism, the second connecting pipe is intermittently connected. Air only enters the anaerobic reactor through the second aeration head when the second connecting pipe is connected. This small amount of air primarily suspends the activated sludge, preventing short-circuiting and dead zones, allowing the bacteria in the activated sludge to fully react with the pre-treated wastewater. The specific reaction process involves NH3 and NO2... - Under the action of anaerobic ammonia-oxidizing bacteria, nitrogen is converted into nitrogen (N2). When the total nitrogen removal rate of the pre-treated waste liquid in the anaerobic reactor reaches more than 80%, the waste liquid can be discharged from the anaerobic reactor, completing the waste liquid treatment.

[0007] The benefits of this plan are as follows: 1. In this solution, the SBR method is used to treat urea waste liquid. The final product does not contain any pollutants, is safe, green and environmentally friendly, and has low equipment investment and low operating costs, making it very economical.

[0008] 2. Urea-hydrolyzing bacteria and ammonia-oxidizing bacteria differ from anaerobic ammonia-oxidizing bacteria. Urea-hydrolyzing bacteria and ammonia-oxidizing bacteria are aerobic, while anaerobic ammonia-oxidizing bacteria are anaerobic. Setting up aerobic and anaerobic reactors facilitates the reproduction of different bacterial species in two independent reactors, which is beneficial for the cultivation of dominant species. Enriching urea-hydrolyzing bacteria and ammonia-oxidizing bacteria separately in the aerobic reactor and enriching anaerobic ammonia-oxidizing bacteria in the anaerobic reactor provides a suitable growth environment for functional microorganisms, avoids the contradictions in sludge age and dissolved oxygen concentration among urea-hydrolyzing bacteria, ammonia-oxidizing bacteria, and anaerobic ammonia-oxidizing bacteria, and improves the activity of each functional microorganism and the corresponding pollutant removal efficiency.

[0009] 3. The dissolved oxygen in the aerobic reactor needs to be controlled at 3-5 mg / L. Although the anaerobic reactor is enriched with anaerobic ammonia oxidizing bacteria, a certain amount of air needs to be introduced to suspend the activated sludge, and the dissolved oxygen needs to be controlled at 0.1-0.3 mg / L. In this scheme, the same exhaust device is used to supply air to both the aerobic and anaerobic reactors simultaneously, eliminating the need for a separate exhaust device for the anaerobic reactor. This simplifies the device structure and reduces costs. By setting up an intermittent connection mechanism, the air supply to the anaerobic reactor can be reasonably controlled, avoiding excessive air supply that could damage the growth environment of the anaerobic ammonia oxidizing bacteria.

[0010] Optionally, the internal circulation mechanism includes a circulation pipe and a circulation pump mounted on the circulation pipe. One end of the circulation pipe is connected to the upper part of the aerobic reactor, and the other end is connected to the lower part of the aerobic reactor. When the circulation pump is started, it draws the urea waste liquid from the upper part of the aerobic reactor into the circulation pipe, and then into the lower part of the aerobic reactor. This allows the urea waste liquid to continuously circulate between the aerobic reactor and the circulation pipe, facilitating full contact between the urea waste liquid and the activated sludge, enabling the urea waste liquid to gradually transform under the action of the activated sludge.

[0011] Optionally, the intermittent communication mechanism includes a sealing plate fixed inside the second connecting pipe, a rotating block rotatably connected inside the second connecting pipe, and a power unit for driving the rotating block to rotate; the rotating block is in contact with the sealing plate, a first through hole is opened at the eccentric position of the sealing plate, and a second through hole is opened on the rotating block that can communicate with the first through hole; an annular groove is opened on the second connecting pipe, and the side wall of the rotating block is opposite to the annular groove; the power unit includes a water inlet tank and multiple rotating blades connected to the side wall of the rotating block, the rotating blades passing through the annular groove; the second connecting pipe passes through the water inlet tank, and the rotating blades are located inside the water inlet tank; the circulation pipe is connected to the water inlet tank.

[0012] The intermittent connection mechanism in this scheme utilizes the power of a circulating pump. When the pump operates, it delivers urea waste liquid into the circulating pipe, which then enters the inlet tank. The urea waste liquid impacts the rotating blades, causing them to rotate. During this rotation, the second through-hole intermittently connects with the first through-hole. When this connection is established, gas generated by the exhaust device enters the anaerobic reactor through the exhaust pipe, the second connecting pipe, and the second aeration head, thus intermittently aerating the reactor and controlling the amount of gas supplied. This scheme leverages the power of the circulating pump to drive the intermittent connection mechanism, allowing the pump to both transport liquid and provide additional power to the mechanism, fully utilizing system resources. Furthermore, the ingenious design of the intermittent connection mechanism effectively controls the amount of gas supplied to the anaerobic reactor by controlling the sizes of the first and second through-holes, eliminating the need for a separate aeration device.

[0013] Optionally, the aerobic reactor is equipped with a stirring device, which includes a stirring rod, a motor for driving the stirring rod to rotate, and multiple blades connected to the stirring rod. The stirring device allows for more thorough contact between the urea waste liquid and the activated sludge, which is beneficial for the treatment of the urea waste liquid.

[0014] Optionally, the first aeration head is rotatably connected to the first connecting pipe, and the lower end of the stirring rod is connected to the first aeration head. The rotation centers of the stirring rod and the first connecting pipe are located on the same straight line. With this configuration, the stirring rod can drive the first aeration head to rotate, and the gas discharged from the first aeration head can also move along with it. The gas stirs the activated sludge, which allows for better contact between the gas and the activated sludge, and is beneficial for the reproduction of aerobic bacteria in the activated sludge.

[0015] Optionally, a filter screen is installed in the upper part of the aerobic reactor, and the upper end of the circulation pipe is located above the filter screen. The filter screen can, to some extent, prevent activated sludge from transferring to the upper part of the aerobic reactor, thus avoiding blockage of the circulation pipe caused by the circulation pump drawing activated sludge into it.

[0016] Alternatively, the exhaust device may be an air compressor or a blower. Attached Figure Description

[0017] Figure 1 This is a sectional view of an environmentally friendly urea waste liquid treatment device according to the present invention, taken from a frontal perspective. Figure 2 for Figure 1 Enlarged view of section A. Detailed Implementation

[0018] The following detailed description illustrates the specific implementation method: The reference numerals in the accompanying drawings include: aerobic reactor 10, filter screen 11, first aeration head 12, first connecting pipe 13, anaerobic reactor 20, second aeration head 21, second connecting pipe 22, valve 221, annular groove 222, stirring rod, motor 30, stirring rod 31, blade 32, air compressor 40, exhaust pipe 41, water outlet pipe 50, water inlet pump 51, circulation pipe 60, circulation pump 61, water inlet tank 70, rotating block 80, second through hole 81, rotating blade 82, sealing plate 83, first through hole 84, and limiting ring 85.

[0019] This embodiment is basically as follows: Figure 1 The diagram shows an environmentally friendly urea wastewater treatment device, comprising an exhaust system, an aerobic reactor 10, and an anaerobic reactor 20. The exhaust system can be an air compressor 40 or a blower; in this embodiment, an air compressor 40 is used. An outlet pipe 50 connects the aerobic reactor 10 and the anaerobic reactor 20, and an inlet pump 51 is installed on the outlet pipe 50. Activating the inlet pump 51 transfers the liquid from the aerobic reactor 10 to the anaerobic reactor 20. The aerobic reactor 10 is equipped with an internal circulation mechanism, which includes a circulation pipe 60 and a circulation pump 61 installed on the circulation pipe 60. One end of the circulation pipe 60 is connected to the upper part of the aerobic reactor 10, and the other end is connected to the lower part of the aerobic reactor 10. Activating the circulation pump 61 allows the liquid in the aerobic reactor 10 to continuously circulate between the aerobic reactor 10 and the circulation pipe 60. A filter screen 11 is fixedly installed inside the upper part of the aerobic reactor 10, and the upper end of the circulation pipe 60 is located above the filter screen 11. The filter screen 11 can, to some extent, prevent the activated sludge from transferring to the upper part of the aerobic reactor 10, and prevent the circulating pump 61 from drawing the activated sludge into the circulating pipe 60, causing blockage of the circulating pipe 60.

[0020] The aerobic reactor 10 has a first aeration head 12 in its lower part, and the anaerobic reactor 20 has a second aeration head 21 in its lower part. An exhaust pipe 41 is connected to an air compressor 40. A first connecting pipe 13 connects the first aeration head 12 to the exhaust pipe 41, and a second connecting pipe 22 connects the second aeration head 21 to the exhaust pipe 41. A valve 221 is installed on the second connecting pipe 22; closing the valve 221 prevents air from flowing into the second connecting pipe 22. The second connecting pipe 22 is also equipped with an intermittent communication mechanism, such as… Figure 2As shown, the intermittent communication mechanism includes a power unit, a rotating block 80, and a sealing plate 83 fixedly installed inside the second connecting pipe 22. One side of the rotating block 80 contacts and fits against the sealing plate 83. The rotating block 80 is rotatably connected inside the second connecting pipe 22. Specifically, a limiting ring 85 is fixedly installed inside the second connecting pipe 22, and the rotating block 80 is rotatably connected between the limiting ring 85 and the sealing block. A first through hole 84 is opened at an eccentric position on the sealing plate 83, and a second through hole 81 is opened on the rotating block 80 that can communicate with the first through hole 84. An annular groove 222 is opened on the second connecting pipe 22, and the side wall of the rotating block 80 is opposite to the annular groove 222, thus sealing the annular groove 222. The power unit includes a water inlet tank 70 and multiple rotating blades 82 connected to the side wall of the rotating block 80. The rotating blades 82 pass through the annular groove 222. The second connecting pipe 22 passes through the water inlet tank 70, and the water inlet tank 70 is fixed to the second connecting pipe 22. The rotating blades 82 are located inside the water inlet tank 70. The circulation pipe 60 is connected to the water inlet tank 70. The liquid in the circulation pipe 60 can enter the water inlet tank 70 and impact the rotating blade 82 in the water inlet tank 70, causing the rotating blade 82 to rotate.

[0021] The aerobic reactor 10 is equipped with a stirring device, which includes a stirring rod 31, a motor 30, and multiple blades 32 connected to the stirring rod 31. The stirring rod 31 passes through a filter screen 11. The motor 30 is fixedly mounted on the upper part of the aerobic reactor 10 by a mounting bracket (not shown in the figure), and the output shaft of the motor 30 is welded to the upper end of the stirring rod 31. The first aeration head 12 is rotatably connected to the first connecting pipe 13, and the lower end of the stirring rod 31 is welded to the first aeration head 12. The rotation centers of the stirring rod 31 and the first connecting pipe 13 are located on the same straight line.

[0022] The working principle of this solution is as follows: Both aerobic reactor 10 and anaerobic reactor 20 contain activated sludge. The activated sludge in aerobic reactor 10 mainly contains urea hydrolyzing bacteria and ammonia oxidizing bacteria, while the activated sludge in anaerobic reactor 20 mainly contains anaerobic ammonia oxidizing bacteria. When the treatment device is initially put into operation, aerobic reactor 10 treats the urea waste liquid first, while anaerobic reactor 20 is not operating. After aerobic reactor 10 completes the treatment of the urea waste liquid (when the urea removal rate in the urea waste liquid reaches over 90%), the inlet pump 51 is started to transfer the treated urea waste liquid (hereinafter referred to as the preliminary treated waste liquid) from aerobic reactor 10 to anaerobic reactor 20 through outlet pipe 50. Anaerobic reactor 20 then further treats the preliminary treated waste liquid. While anaerobic reactor 20 is further treating the preliminary treated waste liquid, new urea waste liquid is added to aerobic reactor 10. Both aerobic reactor 10 and anaerobic reactor 20 can operate simultaneously.

[0023] The working process when aerobic reactor 10 and anaerobic reactor 20 operate simultaneously is as follows: New urea waste liquid is added to aerobic reactor 10, and simultaneously, circulation pump 61, air compressor 40, and valve 221 are turned on. Circulation pump 61 circulates the urea waste liquid in aerobic reactor 10, while air compressor 40 introduces air through exhaust pipe 41 into first connecting pipe 13 and second connecting pipe 22. The air enters aerobic reactor 10 through first connecting pipe 13 and first aeration head 12 for thorough aeration. The activated sludge bacteria in aerobic reactor 10 multiply fully and react with the urea waste liquid. Urea and oxygen are converted into NH3 and CO2 under the action of urea hydrolytic bacteria, and NH3 and oxygen are then converted into NO2 under the action of ammonia oxidizing bacteria. - When the circulating pump 61 is working, it transports urea waste liquid into the circulating pipe 60, and then into the inlet tank 70 through the circulating pipe 60. The urea waste liquid impacts the rotating blade 82, which drives the rotating block 80 to rotate. During the rotation of the rotating block 80, the second through hole 81 can intermittently connect with the first through hole 84. When the second through hole 81 connects with the first through hole 84, the air generated by the air compressor 40 enters the anaerobic reactor 20 through the exhaust pipe 41, the second connecting pipe 22, and the second aeration head 21, realizing intermittent aeration of the anaerobic reactor 20. A small amount of air enters the anaerobic reactor 20. This small amount of air mainly suspends the activated sludge, avoiding short-circuiting and dead zones, so that the bacteria in the activated sludge can fully react with the pre-treated waste liquid. The specific reaction process is NH3 and NO2. - Under the action of anaerobic ammonia-oxidizing bacteria, it is converted into N2. When the total nitrogen removal rate of the pre-treated waste liquid in anaerobic reactor 20 reaches more than 80%, the waste liquid can be discharged from anaerobic reactor 20, completing the treatment of the waste liquid.

[0024] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics in the solutions is not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or its practicality.

Claims

1. An environmentally friendly urea wastewater treatment device, characterized in that: The system includes an exhaust system, an aerobic reactor, and an anaerobic reactor. An outlet pipe connects the aerobic and anaerobic reactors, and an inlet pump is installed on the outlet pipe. The aerobic reactor is equipped with an internal circulation mechanism for circulating the liquid within it. A first aeration head is located in the lower part of the aerobic reactor, and a second aeration head is located in the lower part of the anaerobic reactor. An exhaust pipe is connected to the exhaust system. A first connecting pipe connects the first aeration head to the exhaust pipe, and a second connecting pipe connects the second aeration head to the exhaust pipe. The second connecting pipe is equipped with an intermittent connection mechanism and a valve. The internal circulation mechanism includes a circulation pipe and a circulation pump mounted on the circulation pipe. One end of the circulation pipe is connected to the upper part of the aerobic reactor, and the other end is connected to the lower part of the aerobic reactor. The intermittent communication mechanism includes a sealing plate fixed inside the second connecting pipe, a rotating block rotatably connected inside the second connecting pipe, and a power unit for driving the rotating block to rotate. The rotating block is in contact with the sealing plate, and a first through hole is opened at the eccentric position of the sealing plate. A second through hole is opened on the rotating block that can communicate with the first through hole. An annular groove is opened on the second connecting pipe, and the side wall of the rotating block is opposite to the annular groove. The power unit includes an inlet tank and multiple rotating blades connected to the side wall of the rotating block. The rotating blades pass through the annular groove. The second connecting pipe passes through the inlet tank, and the rotating blades are located inside the inlet tank. The circulation pipe is connected to the inlet tank.

2. The environmentally friendly urea waste liquid treatment device according to claim 1, characterized in that: The aerobic reactor is equipped with a stirring device, which includes a stirring rod, a motor that drives the stirring rod to rotate, and multiple blades connected to the stirring rod.

3. The environmentally friendly urea wastewater treatment device according to claim 2, characterized in that: The first aeration head is rotatably connected to the first connecting pipe, and the lower end of the stirring rod is connected to the first aeration head. The rotation centers of the stirring rod and the first connecting pipe are located on the same straight line.

4. The environmentally friendly urea wastewater treatment device according to claim 1, characterized in that: The upper part of the aerobic reactor is equipped with a filter screen, and the upper end of the circulation pipe is located above the filter screen.

5. The environmentally friendly urea wastewater treatment device according to claim 1, characterized in that: The exhaust system is an air compressor or a blower.

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