Municipal sewage biochemical treatment system for maintaining stable operation of anaerobic ammonia oxidation process

Abstract

The invention discloses a municipal sewage biochemical treatment system capable of maintaining stable operation of an anaerobic ammonia oxidation process. A microorganism expanding culture device, a microorganism screening device and a microorganism hatching device are additionally arranged on the basis of an existing biochemical treatment process. The microorganism expanding culture device is arranged outside an existing biochemical treatment process system, anaerobic ammonium oxidation bacteria in an existing biochemical system are used as mother bacteria, the anaerobic ammonium oxidation bacteria are expanded and cultured, and the anaerobic ammonium oxidation bacteria are supplemented. The microorganism screening device is arranged outside the existing biochemical treatment process system, intercepts anaerobic ammonium oxidation bacteria, discharges inorganic sludge with poor activity, discharges aged sludge with poor cohesiveness, and improves the concentration of activated sludge of the system. The microbial incubation device is arranged in an aerobic tank in an existing biochemical treatment process system, the proliferation speed of anaerobic ammonium oxidation bacteria is increased, internal circulation is increased, stirring is enhanced, and the sludge character is improved. According to the invention, the municipal sewage anaerobic ammonia oxidation treatment process is rapidly started, and stable operation of the municipal sewage anaerobic ammonia oxidation treatment process is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment and denitrification, and in particular to a municipal sewage biochemical treatment system for maintaining stable operation of an anaerobic ammonium oxidation process. Background Art

[0002] The biochemical treatment system of municipal sewage treatment plants usually adopts the activated sludge method. As the environment's total nitrogen index becomes stricter, various denitrification processes have emerged, but most of them focus on the anoxic section of the activated sludge process. There are various methods, such as increasing the retention time of the anoxic section, strengthening the stirring intensity of the anoxic section, controlling the dissolved oxygen of the mixed liquid refluxed to the anoxic section, grading the anoxic section, adding various fillers to the anoxic section, and setting up a post-anoxic section.

[0003] Among the municipal sewage biochemical treatment processes, the best denitrification process is the anaerobic ammonium oxidation process. The anaerobic ammonium oxidation process not only has a good denitrification effect, but also saves energy. The key to its operation is to allow the anaerobic ammonium oxidizing bacteria in the system to reach and maintain a certain abundance.

[0004] The existing municipal sewage anaerobic ammonium oxidation treatment process is mainly a process optimized on the basis of the activated sludge method. The key to its commissioning and operation is to adjust the ordinary activated sludge system to an anaerobic ammonium oxidation activated sludge system, that is, to allow the anaerobic ammonium oxidizing bacteria in the biochemical system to reach and maintain a certain abundance. Anaerobic ammonium oxidizing bacteria usually exist in ordinary activated sludge systems, but the abundance is too low to show any effect. Anaerobic ammonium oxidizing bacteria are autotrophic anaerobic bacteria with slow reproduction and long doubling time. If certain means and measures are not taken, it is difficult to enrich and reach a certain abundance in the biochemical system.

[0005] The usual means and measures to enrich anaerobic ammonium oxidizing bacteria are to add fillers in the anoxic section, allowing the anaerobic ammonium oxidizing bacteria to attach to the fillers in the anoxic section. Through long-term operation, they slowly accumulate and then reach a certain abundance.

[0006] The main disadvantages of the current anaerobic ammonium oxidation technology are that the anaerobic ammonium oxidizing bacteria are slow to enrich and have a long doubling time. The cycle of switching from a common activated sludge ecosystem to an anaerobic ammonium oxidation activated sludge ecosystem is too long, and it does not have the value of industrial promotion. The anaerobic ammonium oxidation system is prone to instability, and once it is unstable, the recovery period is too long.

[0007] Therefore, how to accelerate the enrichment of anaerobic ammonium oxidizing bacteria, how to shorten the startup cycle of the anaerobic ammonium oxidizing process, and how to maintain the stable operation of the anaerobic ammonium oxidizing process are still new topics. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a municipal sewage biochemical treatment system that maintains the stable operation of the anaerobic ammonium oxidation process. By setting up three auxiliary facilities, namely a microbial expansion device, a microbial screening device and a microbial incubation device, the purpose of accelerating the start-up of the municipal sewage anaerobic ammonium oxidation process and maintaining the stable operation of the municipal sewage anaerobic ammonium oxidation process can be achieved.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: a municipal sewage biochemical treatment system for maintaining stable operation of an anaerobic ammonium oxidation process, comprising an anaerobic tank, an anoxic tank, an aerobic tank and a sedimentation tank connected in sequence, the anaerobic tank is provided with a biochemical system water inlet, the sedimentation tank is provided with a biochemical system water outlet, a mixed liquid return pipe is connected between the aerobic tank and the anoxic tank, a sludge return pipe is connected between the sedimentation tank and the anaerobic tank, a microbial expansion device is connected between the aerobic tank and the anaerobic tank through a pipeline, and a first lifting pump is provided on the pipeline between the aerobic tank and the microbial expansion device; a microbial screening device is connected between the sedimentation tank and the anaerobic tank through a pipeline, a second lifting pump is provided on the pipeline between the sedimentation tank and the microbial screening device, and a sludge discharge port is provided on the microbial screening device; a plurality of microbial incubation devices are provided in the aerobic tank.

[0010] The microorganism incubation device is provided with a third lifting pump, and the third lifting pump draws the mixed liquid from the aerobic pool into the microorganism incubation device, and then flows into the aerobic pool by gravity.

[0011] The microorganism expansion device draws mixed liquid from the aerobic tank into the microorganism expansion device, and then flows into the anaerobic tank by gravity.

[0012] The microbial screening device extracts the activated sludge after precipitation from the sedimentation tank and enters the microbial screening device. The sludge with good activity separated after screening flows into the anaerobic tank by gravity, and the sludge with poor activity separated after screening is discharged from the sludge discharge port.

[0013] The mass ratio of the sludge with good activity to the sludge with poor activity separated after the screening is 1:1-3:1.

[0014] The mixed liquid extraction volume of each set of the microbial incubation device is 15-25m 3 / h, the microbial incubation device is arranged at a density of 5-10m in the aerobic pool. 2 / set.

[0015] The beneficial effect of the present invention is that by combining the microorganism expansion device, the microorganism screening device and the microorganism incubation device, the municipal sewage anaerobic ammonia oxidation treatment process can be quickly started and the municipal sewage anaerobic ammonia oxidation treatment process can be stably operated. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a municipal sewage biochemical treatment system for maintaining stable operation of an anaerobic ammonium oxidation process according to the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0019] In addition, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features.

[0020] Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0021] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0022] The electrical devices, controllers, etc. described in the present invention are all conventionally configured, and the electrical connection method is also conventionally connected.

[0023] like Figure 1As shown, the municipal sewage biochemical treatment system for maintaining stable operation of the anaerobic ammonium oxidation process of the present invention comprises an anaerobic tank 5, an anoxic tank 6, an aerobic tank 7 and a sedimentation tank 8 which are connected in sequence, the anaerobic tank 5 is provided with a biochemical system water inlet 12, the sedimentation tank 8 is provided with a biochemical system water outlet 13, a mixed liquid return pipe 14 is connected between the aerobic tank 7 and the anoxic tank 6, a sludge return pipe 15 is connected between the sedimentation tank 8 and the anaerobic tank 5, a microorganism expansion device 2 is connected between the aerobic tank 7 and the anaerobic tank 5 through a pipeline, and a first lifting pump 9 is provided on the pipeline between the aerobic tank 7 and the microorganism expansion device 2; a microorganism screening device 4 is connected between the sedimentation tank 8 and the anaerobic tank 5 through a pipeline, a second lifting pump 11 is provided on the pipeline between the sedimentation tank 8 and the microorganism screening device 4, and a sludge discharge port 16 is provided on the microorganism screening device 4; a plurality of microorganism incubation devices 3 are provided in the aerobic tank 7.

[0024] Furthermore, the microorganism incubation device 3 is provided with a third lifting pump 10 , and the third lifting pump 10 draws the mixed liquid from the aerobic tank 7 into the microorganism incubation device 3 , and then flows into the aerobic tank 7 by gravity.

[0025] The microorganism expansion device 2 draws the mixed liquid from the aerobic tank 7 into the microorganism expansion device, and then flows into the anaerobic tank 5 by gravity.

[0026] The microbial screening device 4 extracts the precipitated activated sludge from the sedimentation tank 8 and enters the microbial screening device. The sludge with good activity separated after screening flows into the anaerobic tank 5 by gravity, and the sludge with poor activity separated after screening is discharged from the sludge discharge port 16.

[0027] Preferably, the mass ratio of the sludge with good activity to the sludge with poor activity separated after the screening is 1:1-3:1.

[0028] Preferably, the mixed liquid extraction volume of each set of the microbial incubation device 3 is 15-25m 3 / h, the microbial incubation device is arranged at a density of 5-10m in the aerobic pool. 2 / set.

[0029] The main function of the microbial expansion device of the present invention is to expand the anaerobic ammonia oxidizing bacteria with the anaerobic ammonia oxidizing bacteria in the primary chemical treatment process system as the mother bacteria, and continuously replenish the anaerobic ammonia oxidizing bacteria into the primary chemical treatment process system. The main function of the microbial screening device is to intercept the anaerobic ammonia oxidizing bacteria, discharge the inorganic sludge with poor activity, discharge the aged sludge with poor cohesion, and increase the concentration of the active sludge in the primary chemical treatment process system. The main function of the microbial incubation device is to increase the proliferation rate of the anaerobic ammonia oxidizing bacteria, increase the internal circulation and strengthen the stirring, and improve the sludge properties.

[0030] The present invention creatively combines these three devices to quickly start the anaerobic ammonium oxidation treatment process for municipal sewage, and enables the anaerobic ammonium oxidation treatment process for municipal sewage to operate stably. If only a microbial expansion device is used, but a microbial screening device and a microbial incubation device are not used, the anaerobic ammonium oxidizing bacteria in the biochemical treatment system will reproduce very slowly. When the biochemical treatment system normally discharges excess sludge, the newly accumulated anaerobic ammonium oxidizing bacteria are also discharged. Therefore, the anaerobic ammonium oxidizing bacteria cannot form a dominant bacterial community in the biochemical treatment system, and the anaerobic ammonium oxidation treatment process for municipal sewage cannot be quickly started. Unless the scale of the microbial expansion device is increased, the cost performance is poor and there is no economic benefit. If a microbial expansion device is used, and a microbial screening device is used, but a microbial incubation device is not used, the anaerobic ammonium oxidizing bacteria in the biochemical treatment system will reproduce very slowly. When the biochemical treatment system normally discharges excess sludge, part of the anaerobic ammonium oxidizing bacteria can also be intercepted and accumulated through microbial screening, but it takes a long time for the anaerobic ammonium oxidizing bacteria to form a dominant bacterial community in the biochemical treatment system. The anaerobic ammonium oxidation treatment process for municipal sewage can be started, but it cannot be started quickly. If a microbial expansion device is used, and then a microbial incubation device is used instead of a microbial screening device, the reproduction of anaerobic ammonia oxidizing bacteria in the biochemical treatment system can be accelerated, and other microorganisms will reproduce faster. When the residual sludge is discharged normally in the biochemical treatment system, part of the anaerobic ammonia oxidizing bacteria is not intercepted by the microbial screening device, and the anaerobic ammonia oxidizing bacteria cannot form a dominant flora in the biochemical treatment system, making it difficult to start the municipal sewage anaerobic ammonia oxidation treatment process. Adding fillers to the anoxic tank can ensure that the municipal sewage anaerobic ammonia oxidation treatment process can be started, but because the concentration of anaerobic ammonia oxidizing bacteria in the activated sludge is too low, it takes too long to retain a sufficient abundance of anaerobic ammonia oxidizing bacteria on the fillers, so it cannot be started quickly. If a microbial expansion device is not used, only a microbial screening device and a microbial incubation device are used. The municipal sewage anaerobic ammonia oxidation treatment process can be started by inoculating anaerobic ammonia oxidizing bacteria, and the amount of inoculated anaerobic ammonia oxidizing bacteria determines the speed of the start-up. However, the biochemical treatment system is easily impacted, the anaerobic ammonia oxidation treatment process is very unstable, and the effluent effect cannot be guaranteed. Frequent inoculation of anaerobic ammonia oxidizing bacteria is not economical.

[0031] The present invention does not change the original municipal sewage biochemical treatment system 1, but sets three auxiliary facilities, namely a microorganism expansion device 1, a microorganism screening device 2 and a microorganism incubation device 3, to achieve the purpose of accelerating the start-up of the municipal sewage anaerobic ammonia oxidation process and maintaining the stable operation of the municipal sewage anaerobic ammonia oxidation process. It includes the following steps:

[0032] Step 1, without changing the original municipal sewage biochemical treatment process, an external auxiliary facility - microbial expansion device 2 is added on the basis of the original biochemical treatment system 1. The microbial expansion device 2 is arranged outside the original biochemical treatment system 1. The microbial expansion device 2 is connected to the original biochemical treatment system 1 in such a way that the first lifting pump 9 extracts the mixed liquid from the aerobic tank 7 of the original biochemical treatment system 1 into the microbial expansion device 2, and then flows by gravity into the anaerobic tank 5 of the original biochemical treatment system 1. The microbial expansion device 2 is an integrated device. The amount of mixed liquid extracted is (0.5%-1%) Q, where Q is the water inlet flow rate. The main function of the microbial expansion device 2 is to use the anaerobic ammonia-oxidizing bacteria in the system of the original biochemical treatment system 1 as the mother bacteria to expand the anaerobic ammonia-oxidizing bacteria, and can continuously supplement the anaerobic ammonia-oxidizing bacteria into the system of the original biochemical treatment system 1.

[0033] Step 2, without changing the original municipal sewage biochemical treatment process, an external auxiliary facility, a microbial screening device 4, is added to the original biochemical treatment system 1. The microbial screening device 4 is arranged outside the original biochemical treatment system 1. The microbial screening device 4 is connected to the original biochemical treatment system 1 in such a way that the second lifting pump 11 extracts the precipitated activated sludge from the sedimentation tank 8 of the original biochemical treatment system 1 into the microbial screening device 4, and the outlet of the microbial screening device 4 is divided into two paths, one of which is the sludge with good activity separated after screening, and the sludge with good activity flows into the anaerobic tank 5 of the original biochemical treatment system 1 by gravity; the other is the sludge with poor activity separated after screening, and the sludge with poor activity is discharged from the original biochemical treatment system 1 as residual sludge. The microbial screening device 3 is an integrated device. The activated sludge after precipitation is extracted from the sedimentation tank 8 of the original biochemical treatment system 1 and enters the microbial screening device 4, and the extraction amount of the activated sludge after precipitation is (5%-10%) Q, where Q is the water inlet flow rate. The screening ratio of the microbial screening device 4 is 50-70%, that is, the ratio of the amount of sludge with good activity to the amount of sludge with poor activity separated after screening is 1:1-3:1. The main functions of the microbial screening device 4 are to intercept anaerobic ammonia oxidizing bacteria, discharge inorganic sludge with poor activity, discharge aged sludge with poor cohesion, and increase the concentration of active sludge in the primary chemical treatment system 1.

[0034] Step 3, without changing the original municipal sewage biochemical treatment process, an internal auxiliary facility - a microbial incubation device 3 is added to the original biochemical treatment system 1. The microbial incubation device 3 is arranged in the aerobic tank 7 in the original biochemical treatment system 1. The microbial incubation device 3 is connected to the original biochemical treatment system 1 in such a way that the third lifting pump 10 draws the mixed liquid from the aerobic tank 7 of the original biochemical treatment system 1 into the microbial incubation device 3, and then flows by gravity into the aerobic tank 7 of the original biochemical treatment process. The microbial incubation device 3 is an integrated device. The mixed liquid is drawn from the aerobic tank 7 of the original biochemical treatment system 1 into the microbial incubation device 3, and the amount of the mixed liquid drawn is 15-25m3 for each set of microbial incubation device 3. 3 / h. The microbial incubation device 3 is arranged in the aerobic pool 7 of the primary biochemical treatment system 1 at a density of 5-10m 2 / set. The main functions of the microbial incubation device 3 are to increase the proliferation rate of anaerobic ammonia-oxidizing bacteria, increase internal circulation, strengthen stirring, and improve sludge properties.

[0035] Through the above three methods, the municipal sewage anaerobic ammonium oxidation treatment process can be quickly started and the municipal sewage anaerobic ammonium oxidation treatment process can be stably operated. The present invention can quickly start the municipal sewage anaerobic ammonium oxidation treatment process and can stably operate the municipal sewage anaerobic ammonium oxidation treatment process.

[0036] Example 1

[0037] A municipal sewage treatment plant in Inner Mongolia, operating scale 15000m 3 / d, the anaerobic ammonium oxidation process was started in early July 2018, and by the end of November 2018, the anaerobic ammonium oxidation was successfully started, and it took 5 months to complete the startup. No anaerobic ammonium oxidizing bacteria were inoculated during the startup process, and only microbial expansion devices and microbial screening devices were used, and no microbial incubation device was used. At the end of December 2018, the microbial expansion device was damaged, and it was difficult for the system to maintain the operation of the anaerobic ammonium oxidation process. In July 2019, a new microbial expansion device was added. The system's anaerobic ammonium oxidation process has temporarily stabilized, but there are still shock fluctuations. In 2021, a microbial incubation device was added to the aerobic pool. After that, the system has been able to maintain the stable operation of the anaerobic ammonium oxidation treatment process.

[0038] Example 2

[0039] A municipal sewage treatment plant in Inner Mongolia, operating scale 25000m 3 / d, and the anaerobic ammonium oxidation process was started in May 2020. By August 2020, the anaerobic ammonium oxidation was successfully started, and it took 4 months to complete the startup. During the startup process, anaerobic ammonium oxidizing bacteria were inoculated, and only microbial expansion devices and microbial screening devices were used, and no microbial incubation devices were used. The system did not run the microbial expansion device afterwards. By the end of November 2020, the anaerobic ammonium oxidation system collapsed, and the biochemical treatment system returned to its original operating state.

[0040] Example 3

[0041] A municipal sewage treatment plant in Inner Mongolia, operating scale 20000m 3 / d, and the anaerobic ammonium oxidation process was started in August 2020. By early October 2020, the anaerobic ammonium oxidation was successfully started, and it took 2 months to complete the startup. During the startup process, anaerobic ammonium oxidizing bacteria were inoculated, and microbial expansion devices, microbial screening devices, and microbial incubation devices were used. After the startup was completed, the microbial expansion device was dismantled. By the end of December 2020, the anaerobic ammonium oxidation system collapsed, and the biochemical treatment system returned to its original operating state.

[0042] In summary, the content of the present invention is not limited to the above-mentioned embodiments, and people with insight in the same field can easily propose other embodiments within the technical guiding ideology of the present invention, but such embodiments are all included in the scope of the present invention.

Claims

1. A municipal sewage biochemical treatment system for maintaining stable operation of an anaerobic ammonium oxidation process, comprising an anaerobic tank (5), an anoxic tank (6), an aerobic tank (7) and a sedimentation tank (8) connected in sequence, the anaerobic tank (5) being provided with a biochemical system water inlet (12), the sedimentation tank (8) being provided with a biochemical system water outlet (13), a mixed liquor return pipe (14) being connected between the aerobic tank (7) and the anoxic tank (6), and a sludge return pipe (15) being connected between the sedimentation tank (8) and the anaerobic tank (5), characterized in that: A microorganism expansion device (2) is connected between the aerobic tank (7) and the anaerobic tank (5) via a pipeline, and a first lifting pump (9) is arranged on the pipeline between the aerobic tank (7) and the microorganism expansion device (2); a microorganism screening device (4) is connected between the sedimentation tank (8) and the anaerobic tank (5) via a pipeline, and a second lifting pump (11) is arranged on the pipeline between the sedimentation tank (8) and the microorganism screening device (4), and a sludge discharge port (16) is arranged on the microorganism screening device (4); and a plurality of microorganism incubation devices (3) are arranged in the aerobic tank (7).

2. The municipal sewage biochemical treatment system for maintaining stable operation of the anaerobic ammonium oxidation process according to claim 1, characterized in that: The microorganism incubation device (3) is provided with a third lifting pump (10), and the third lifting pump (10) draws mixed liquid from the aerobic pool (7) into the microorganism incubation device (3), and then flows into the aerobic pool (7) by gravity.

3. The municipal sewage biochemical treatment system for maintaining stable operation of the anaerobic ammonium oxidation process according to claim 1, characterized in that: The microorganism expansion device (2) draws mixed liquid from the aerobic tank (7) into the microorganism expansion device, and then flows into the anaerobic tank (5) by gravity.

4. The municipal sewage biochemical treatment system for maintaining stable operation of the anaerobic ammonium oxidation process according to claim 1, characterized in that: The microbial screening device (4) extracts the precipitated activated sludge from the sedimentation tank (8) and enters the microbial screening device. The sludge with good activity separated after screening flows into the anaerobic tank (5) by gravity, and the sludge with poor activity separated after screening is discharged from the sludge discharge port (16).

5. The municipal sewage biochemical treatment system for maintaining stable operation of the anaerobic ammonium oxidation process according to claim 4, characterized in that: The mass ratio of the sludge with good activity to the sludge with poor activity separated after the screening is 1:1-3:

1.

6. The municipal sewage biochemical treatment system for maintaining stable operation of the anaerobic ammonium oxidation process according to claim 2, characterized in that: The mixed liquid extraction volume of each set of the microorganism incubation device (3) is 15-25m 3 / h, the microbial incubation device is arranged at a density of 5-10m in the aerobic pool. 2 / set.

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