Urban domestic sewage treatment device based on improved sludge double return Batunfu process

Abstract

The present invention relates to a domestic sewage treatment plant based on a modified sludge double-return Battenfel process. The technical solution comprises a domestic sewage raw water tank, a modified sludge double-return Battenfel reactor, and a sedimentation tank, arranged sequentially along the sewage flow direction. The upper water outlet of the sedimentation tank is connected to an outlet pipe. The reactor comprises an anaerobic zone connected to the sludge outlet of the sedimentation tank via a sludge return line I; a pre-anoxic zone for receiving the mixed liquor after the reaction in the anaerobic zone; an aerobic zone I for oxidizing a portion of the ammonia nitrogen in the mixed liquor after the reaction in the pre-anoxic zone into nitrite, which can also be used by anaerobic ammonia oxidation to produce PNA; an aerobic zone II connected to the pre-anoxic zone via a nitrification liquid return line; a post-anoxic zone connected to the sludge outlet of the sedimentation tank via a sludge return line II; and an aerobic zone III for oxidizing the remaining ammonia nitrogen in the mixed liquor after the reaction in the post-anoxic zone into nitrate. The present invention is applicable to the field of biological sewage treatment.

Description

Technical Field

[0001] The present invention relates to a town domestic sewage treatment device based on an improved sludge double-return Batumu process, which is applicable to the field of sewage biological treatment. Background Art

[0002] In recent years, with the continuous development of society, the discharge of nitrogen and phosphorus wastewater into water bodies has exacerbated eutrophication. Nitrogen and phosphorus removal are key tasks for sewage treatment plants. Due to the low C / N ratio of urban domestic sewage, traditional sewage treatment processes are unable to meet the requirements for nitrogen and phosphorus removal. Therefore, it is necessary to transform traditional processes.

[0003] Anaerobic ammonium oxidizing (ANAMMOX) bacteria can directly convert ammonia nitrogen and nitrite into nitrogen gas. This process offers low energy consumption and high nitrogen removal efficiency, making it a promising denitrification process. Compared to traditional nitrification and denitrification processes, which require high aeration and organic carbon sources, ANAMMOX is an autotrophic denitrification process with lower aeration and organic carbon source costs. Consequently, ANAMMOX technology has garnered widespread attention, particularly for treating urban wastewater with low ammonia nitrogen concentrations.

[0004] Currently, the persistence of anaerobic ammonium oxidizing bacteria and a stable supply of nitrite remain bottlenecks limiting the application of anaerobic ammonium oxidizing (ANAMMOX) in urban wastewater treatment. ANAMMOX bacteria are ubiquitous in traditional urban wastewater treatment plants and can still cause some nitrogen losses even at low abundance.

[0005] There are currently three commonly used processes for providing nitrite substrates for anaerobic ammonium oxidizing bacteria: (1) Short-term nitrification: Through controlled means, ammonia oxidizing bacteria (AOB) are activated, oxidizing ammonia nitrogen to nitrite, which is then reacted with the remaining ammonia nitrogen under the action of anaerobic ammonium oxidizing bacteria. (2) Short-term denitrification: In the presence of an external carbon source, denitrifying bacteria are used to reduce nitrate to nitrite, which is then used together with ammonia nitrogen by anaerobic ammonium oxidizing bacteria. (3) Endogenous short-term denitrification: Using the internal carbon source stored in the previous anaerobic section, in the subsequent treatment section, the internal carbon source is used to reduce nitrate to nitrite, which is then used together with ammonia nitrogen by anaerobic ammonium oxidizing bacteria. Each of the three approaches has its own advantages and disadvantages, but the purpose is to provide a stable substrate nitrite for anaerobic ammonium oxidation. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: in view of the above-mentioned problems, a town domestic sewage treatment device based on the improved sludge double-return Batumu process is provided.

[0007] The technical solution adopted by the present invention is: a town domestic sewage treatment device based on the improved sludge double-return Batumf process, characterized by: a domestic sewage raw water tank, an improved sludge double-return Batumf reactor and a sedimentation tank arranged in sequence along the sewage flow direction, and the upper water outlet of the sedimentation tank is connected to the water outlet pipe;

[0008] The improved sludge double-return Batumu reactor comprises:

[0009] The anaerobic zone is connected to the sludge outlet of the sedimentation tank via the sludge return line I, and is used to convert the easily degradable organic matter in the sewage raw water sent from the domestic sewage raw water tank into an internal carbon source, and is used to reduce the nitrate carried in the sludge returned from the sedimentation tank into nitrogen gas by using denitrifying bacteria, and to achieve PDA (short-cut denitrification anaerobic ammonium oxidation) under the conditions of anaerobic ammonium oxidation fillers to remove nitrate and part of the ammonia nitrogen;

[0010] The front anoxic zone is used to receive the mixed liquid after the reaction in the anaerobic zone and to remove the nitrate and part of the ammonia nitrogen flowing back to the front anoxic zone through the combined action of denitrification and PDA;

[0011] The first aerobic zone is used to oxidize part of the ammonia nitrogen in the mixed solution after the reaction in the pre-anoxic zone into nitrite, which can be used by anaerobic ammonium oxidation to produce PNA (short-range nitrification anaerobic ammonium oxidation);

[0012] The second aerobic zone is connected to the anoxic zone via a nitrification liquid reflux pipeline and is used to oxidize most of the ammonia nitrogen in the mixed liquid after the reaction in the first aerobic zone into nitrate under aeration conditions;

[0013] The post-anoxic zone is connected to the mud outlet of the sedimentation tank via the sludge return pipeline II, and is used to receive the mixed liquor after the reaction in the aerobic zone II, and utilize the internal carbon source in the mixed liquor converted in the anaerobic zone and the internal carbon source carried by the return sludge from the sedimentation tank to reduce the nitrate in the mixed liquor and the return sludge to nitrite. The ammonia nitrogen in the mixed liquor can be utilized by anaerobic ammonium oxidizing bacteria to generate nitrogen gas, and EPDA (endogenous short-range denitrification coupled with anaerobic ammonium oxidation) occurs;

[0014] The aerobic zone 3 is used to oxidize the remaining ammonia nitrogen in the mixed solution after the reaction in the post-anoxic zone into nitrate.

[0015] The anaerobic zone, the front anoxic zone and the rear anoxic zone are inoculated with anaerobic ammonium oxidation fillers.

[0016] The filling ratio of the anaerobic ammonium oxidation filler is 10%-15%.

[0017] The dissolved oxygen in the aerobic zone 1 is 0.3-0.8 mg / L; the dissolved oxygen in the aerobic zone 2 is 1.5-2.0 mg / L.

[0018] The aerobic zone 1, aerobic zone 2 and aerobic zone 3 are respectively equipped with a zone 1 aeration device, a zone 2 aeration device and a zone 3 aeration device; the aerobic zone 1 and aerobic zone 2 are respectively provided with a zone 1 DO meter and a zone 2 DO meter.

[0019] The anaerobic zone, the front anoxic zone and the rear anoxic zone are respectively provided with an anaerobic stirrer, a front anoxic stirrer and a rear anoxic stirrer.

[0020] The sludge concentration in the improved sludge double-circulation Batumu reactor is maintained at 3500-4500 mg / L.

[0021] In the improved sludge double-reflux Batum reactor, the nitrification liquid reflux ratio is 200%-300%, and the sludge reflux ratio is 80%-150%.

[0022] The beneficial effects of the present invention are as follows: PDA reactions occur in the anaerobic zone and pre-anoxic zone, followed by PNA by adding anaerobic ammonium oxidizing fillers to the aerobic first zone. In the post-anoxic zone, anaerobic storage and sludge recirculation provide an internal carbon source for EPDA. Nitrite is provided to anaerobic ammonium oxidizing bacteria through three pathways: short-range denitrification, short-range denitrification with an internal carbon source, and short-range nitrification. This continuously enriches the anaerobic ammonium oxidizing bacteria and ultimately achieves deep denitrification using the modified sludge double-recirculation Batumu process.

[0023] The present invention provides nitrite substrates for anaerobic ammonium oxidizing bacteria in multiple ways, which is beneficial to the enrichment and growth of anaerobic ammonium oxidizing bacteria and provides a feasible solution for the application of mainstream anaerobic ammonium oxidizing processes; it couples multiple denitrification processes to achieve synergistic denitrification by heterotrophic denitrifying bacteria and anaerobic ammonium oxidizing bacteria; the method of the present invention is simple, flexible in operation, and highly operable, and is suitable for upgrading and renovating existing urban sewage treatment plants, and is suitable for the treatment of urban domestic sewage with a low carbon-nitrogen ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of the embodiment.

[0025] 1. Domestic sewage raw water tank; 2. Water inlet pump; 3. Improved sludge double-return Batum reactor; 3-1. Anaerobic zone; 3-2. Pre-anoxic zone; 3-3. Aerobic zone 1; 3-4. Aerobic zone 2; 3-5. Post-anoxic zone; 3-6. Aerobic zone 3; 4. Sedimentation tank; 5. Outlet pipe; 6-1. Anaerobic agitator; 6-2. Pre-anoxic agitator; 6-3. Post-anoxic agitator; 7-1. DO meter for zone 1; 7-2. DO meter for zone 2; 8-1. Anaerobic zone sludge return pump; 8-2. Post-anoxic sludge return pump; 8-3. Nitration solution return pump; 9. Aeration pump; 10-1. Aeration device for zone 1; 10-2. Aeration device for zone 2; 10-3. Aeration device for zone 3; 11. Anaerobic ammonium oxidation filler. DETAILED DESCRIPTION

[0026] like Figure 1As shown, this embodiment is a municipal domestic sewage treatment device based on the improved sludge double-return Batumfu process, which has a domestic sewage raw water tank, an improved sludge double-return Batumfu reactor and a sedimentation tank connected in sequence along the sewage flow direction, wherein an inlet pump is provided between the domestic sewage raw water tank and the improved sludge double-return Batumfu reactor, and the upper water outlet of the sedimentation tank is connected to the outlet pipe.

[0027] In this example, the improved sludge double-return Batum reactor has an anaerobic zone, a front anoxic zone, an aerobic zone 1, an aerobic zone 2, a post-anoxic zone and an aerobic zone 3 arranged in sequence along the sewage flow direction. The volume ratio of each process zone is anaerobic: front anoxic: aerobic zone 1: aerobic zone 2: post-anoxic: aerobic zone 3 = 1:1:1:1:1:1.

[0028] In this embodiment, a zone 1 aeration device, a zone 2 aeration device, and a zone 3 aeration device are installed in the aerobic zone 1, a zone 2 aeration device, and a zone 3 aeration device, respectively, and the zone 1 aeration device, the zone 2 aeration device, and the zone 3 aeration device are all connected to the aeration pump; a zone 1 DO meter and a zone 2 DO meter are provided corresponding to the aerobic zone 1 and the aerobic zone 2, respectively.

[0029] In this embodiment, the mud outlet of the sedimentation tank is connected to the anaerobic zone through the sludge return pipeline I, and the mud return pipeline I is provided with an anaerobic zone sludge return pump for returning part of the sludge in the sedimentation tank to the anaerobic zone; the mud outlet of the sedimentation tank is connected to the post-anoxic zone through the sludge return pipeline II, and the mud return pipeline II is provided with a post-anoxic sludge return pump for returning part of the sludge in the sedimentation tank to the post-anoxic zone; the aerobic zone II is connected to the front anoxic zone through the digestate return pipeline, and the digestate return pipeline is provided with a nitrification liquid reflux pump for returning part of the digestate in the aerobic zone II to the front anoxic zone.

[0030] In this example, the modified sludge double-return Batumfu reactor was inoculated with excess sludge from a municipal sewage treatment plant, and the sludge concentration in the modified sludge double-return Batumfu reactor was maintained at 3500-4500 mg / L; anaerobic ammonium oxidation fillers were inoculated in the anaerobic zone, pre-anoxic zone, and post-anoxic zone, respectively, with a filling ratio of 10%-15%; the influent was municipal domestic sewage with a COD of 100-200 mg / L, NH4+-N of 25-50 mg / L, and a C / N ratio of 2-4; the nitrification solution return ratio was 200%-300%, and the sludge return ratio was 80%-150%; the dissolved oxygen in the aerobic zone 1 was controlled at 0.3-0.8 mg / L, the dissolved oxygen in the aerobic zone 2 was controlled at 1.5-2.0 mg / L, and the dissolved oxygen in the aerobic zone 3 was controlled at 1.5-2.0 mg / L.

[0031] In this embodiment, urban domestic sewage enters the anaerobic zone from the domestic sewage raw water tank through the water inlet pump, and is connected to the front anoxic zone, aerobic zone 1, aerobic zone 2, rear anoxic zone and aerobic zone 3 through pipes in sequence, and then flows into the secondary sedimentation tank and is discharged through the outlet pipe after sedimentation.

[0032] The working principle of the sewage treatment device in this embodiment is as follows:

[0033] All sewage in the domestic sewage raw water tank is continuously pumped into the anaerobic zone of the modified sludge double-return Batum reactor through the water inlet pump and anaerobic stirring is carried out to convert the easily degradable organic matter in the raw water into an internal carbon source. The nitrate carried in the return sludge can be reduced to nitrogen gas by denitrifying bacteria in the anaerobic zone. In addition, PDA can be used to remove nitrate and part of ammonia nitrogen under the condition of adding anaerobic ammonium oxidation filler. The hydraulic retention time in the anaerobic zone is maintained at 2-3h.

[0034] The mixed liquid after the reaction in the anaerobic zone flows into the front anoxic zone, where the nitrate and part of the ammonia nitrogen in the nitrification liquid return can be removed through the combined action of denitrification and PDA;

[0035] The mixed liquid after the reaction in the front anoxic zone flows into the aerobic zone 1, where anaerobic ammonium oxidation filler is added and the dissolved oxygen in the aerobic zone 1 is controlled at 0.3-0.8 mg / L, so that part of the ammonia nitrogen in the aerobic zone 1 can be oxidized into nitrite and utilized by anaerobic ammonium oxidation at the same time, resulting in short-term nitrification and anaerobic ammonium oxidation;

[0036] The mixed liquid carries nitrate and remaining ammonia nitrogen into the second aerobic zone, where most of the ammonia nitrogen is oxidized to nitrate under aeration conditions, with a small amount of ammonia nitrogen remaining.

[0037] In the post-anoxic zone, heterotrophic denitrifying bacteria in the mixed liquid after the reaction in the aerobic zone use the internal carbon source carried by the return sludge and the internal carbon source stored in the anaerobic zone to reduce the nitrate in the aerobic zone and the sludge return to nitrite. The nitrate and the remaining ammonia nitrogen in the aerobic zone are simultaneously used by anaerobic ammonia-oxidizing bacteria to generate nitrogen gas and generate EPDA, thereby achieving the purpose of deep denitrification.

[0038] The mixed liquid after the reaction in the post-anoxic zone enters the aerobic zone 3, which can ensure that the remaining ammonia nitrogen is oxidized into nitrate and discharged into the water. The final effluent water quality is: COD: 20-45mg / L, TN: 5-8mg / L.

[0039] In this embodiment, the hydraulic retention time in the front anoxic zone (3-2), aerobic zone 1 (3-3), aerobic zone 2 (3-4), post-anoxic zone (3-5), and aerobic zone 3 (3-6) is 2-3 hours. The nitrification liquid return ratio is preferably 200%, and the anaerobic zone sludge return ratio and the post-anoxic sludge return ratio are preferably 100%.

Claims

1. A town sewage treatment plant based on the improved sludge double-return Batunfu process, characterized by: It has a domestic sewage raw water tank, an improved sludge double-return Batumu reactor and a sedimentation tank arranged in sequence along the sewage flow direction, and the upper water outlet of the sedimentation tank is connected to the outlet pipe; The improved sludge double-return Batumu reactor comprises: The anaerobic zone is connected to the sludge outlet of the sedimentation tank via the sludge return pipeline I, and is used to convert the easily degradable organic matter in the sewage raw water sent from the domestic sewage raw water tank into an internal carbon source, and is used to reduce the nitrate carried in the sludge returned from the sedimentation tank into nitrogen gas by using denitrifying bacteria, and to achieve PDA under the conditions of anaerobic ammonium oxidation filler to remove nitrate and part of the ammonia nitrogen; The front anoxic zone is used to receive the mixed liquid after the reaction in the anaerobic zone and to remove the nitrate and part of the ammonia nitrogen flowing back to the front anoxic zone through the combined action of denitrification and PDA; The aerobic zone is used to oxidize part of the ammonia nitrogen in the mixed liquid after the reaction in the anoxic zone into nitrite, which can also be used by anaerobic ammonia oxidation to produce PNA; The second aerobic zone is connected to the anoxic zone via a nitrification liquid reflux pipeline and is used to oxidize most of the ammonia nitrogen in the mixed liquid after the reaction in the first aerobic zone into nitrate under aeration conditions; The post-anoxic zone is connected to the mud outlet of the sedimentation tank via the sludge return pipeline II, and is used to receive the mixed liquor after the reaction in the aerobic zone II, and utilize the internal carbon source in the mixed liquor converted in the anaerobic zone and the internal carbon source carried by the return sludge from the sedimentation tank to reduce the nitrate in the mixed liquor and the return sludge to nitrite. The ammonia nitrogen in the mixed liquor can be utilized by anaerobic ammonia-oxidizing bacteria to generate nitrogen gas, thereby generating EPDA; The third aerobic zone is used to oxidize the remaining ammonia nitrogen in the mixed solution after the reaction in the post-anoxic zone into nitrate; The dissolved oxygen in the aerobic zone 1 is 0.3-0.8 mg / L; the dissolved oxygen in the aerobic zone 2 is 1.5-2.0 mg / L.

2. The urban domestic sewage treatment device based on the improved sludge double-return Batumu process according to claim 1 is characterized in that: The anaerobic zone, the front anoxic zone and the rear anoxic zone are inoculated with anaerobic ammonium oxidation fillers.

3. The urban domestic sewage treatment device based on the improved sludge double-return Batumu process according to claim 2 is characterized in that: The filling ratio of the anaerobic ammonium oxidation filler is 10%-15%.

4. The urban domestic sewage treatment device based on the improved sludge double-return Batumu process according to claim 1 is characterized in that: The aerobic zone 1, aerobic zone 2 and aerobic zone 3 are respectively equipped with a zone 1 aeration device, a zone 2 aeration device and a zone 3 aeration device; the aerobic zone 1 and aerobic zone 2 are respectively provided with a zone 1 DO meter and a zone 2 DO meter.

5. The urban domestic sewage treatment device based on the improved sludge double-return Batumu process according to claim 1 is characterized in that: The anaerobic zone, the front anoxic zone and the rear anoxic zone are respectively provided with an anaerobic stirrer, a front anoxic stirrer and a rear anoxic stirrer.

6. The urban domestic sewage treatment device based on the improved sludge double-return Batumu process according to claim 1 is characterized in that: The sludge concentration in the improved sludge double-circulation Batumu reactor is maintained at 3500-4500 mg / L.

7. The urban domestic sewage treatment device based on the improved sludge double-return Batumu process according to claim 1 is characterized in that: In the improved sludge double-reflux Batum reactor, the nitrification liquid reflux ratio is 200%-300%, and the sludge reflux ratio is 80%-150%.

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