Filter and operation method for realizing hydrogen sulfide reduction and sulfur source regeneration by coupling sulfidogenic denitrification with anaerobic ammonia oxidation based on backwashing strategy

Abstract

This invention relates to a sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation filter and its operation method based on a backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration, belonging to the field of biological wastewater treatment. A backwashing device is installed at the bottom of the filter, and sulfur-containing filter media is dispersed within the filter. The filter outlet is equipped with a dissolved oxygen coupled with a temperature probe and a hydrogen sulfide probe, connected to a real-time monitoring and control system. The sulfur-containing filter media serves as a carrier for the attachment and growth of sulfur autotrophic denitrifying bacteria, sulfate-reducing bacteria, and anaerobic ammonia oxidizing bacteria. The real-time monitoring and control system is configured to activate the backwashing device when the hydrogen sulfide concentration exceeds a set value, injecting a set amount of gas into the filter for backwashing. While ensuring the smooth progress of sulfur autotrophic denitrification, anaerobic ammonia oxidation is coupled, and the oxygen from the backwashing is used to oxidize the hydrogen sulfide, converting it into elemental sulfur, which continues to serve as a sulfur source to drive sulfur autotrophic denitrification and achieve sulfur source regeneration. This effectively reduces the hydrogen sulfide content.

Description

Technical Field

[0001] This invention belongs to the field of biological wastewater treatment and relates to a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter and its operation method based on a backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] The discharge of domestic sewage is increasing year by year. Traditional nitrification-denitrification denitrification processes, due to their drawbacks such as the need for additional carbon sources and large sludge production, not only lead to increased carbon emissions but also increase the operating costs of sludge treatment systems. Sulfur-driven autotrophic denitrification, using sulfur as an electron donor, reduces nitrates in sewage to nitrogen gas; anaerobic ammonium oxidation, another autotrophic denitrification process, utilizes nitrite to oxidize ammonia nitrogen, achieving denitrification of sewage. The combination of these two processes can achieve deep denitrification of domestic sewage, eliminating dependence on external carbon sources. The sulfur autotrophic denitrification coupled with anaerobic ammonium oxidation sewage treatment process holds promise for replacing traditional heterotrophic denitrification filters for denitrification of domestic sewage.

[0004] The sulfur autotrophic denitrification process converts elemental sulfur into sulfate. Because the sulfur autotrophic denitrification filter is an anaerobic environment, sulfate-reducing bacteria in the system reduce the generated sulfate to sulfur ions, which dissolve in water to produce hydrogen sulfide. Hydrogen sulfide is a toxic and harmful gas, harmful to humans; it can also cause pipe corrosion in acidic aqueous solutions, reducing pipe lifespan. Therefore, wastewater treatment processes that couple sulfur autotrophic denitrification with anaerobic ammonia oxidation need to reduce the amount of hydrogen sulfide produced. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter and its operation method based on a backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration. The sulfur autotrophic denitrification filter is monitored in real time, and the concentrations of hydrogen sulfide and dissolved oxygen in the wastewater are adjusted through backwashing to achieve hydrogen sulfide reduction and sulfur source regeneration.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] Firstly, a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter is provided to achieve hydrogen sulfide reduction and sulfur source regeneration based on a backwashing strategy. The filter is equipped with a backwashing device at the bottom and sulfur-containing filter media is dispersed in the water. The outlet of the filter is equipped with a dissolved oxygen coupled temperature probe and a hydrogen sulfide probe, which are connected to a real-time monitoring and control system.

[0008] The sulfur-containing filter media serves as a carrier for the attachment and growth of sulfur-autotrophic denitrifying bacteria and anaerobic ammonia-oxidizing bacteria.

[0009] The real-time monitoring and control system is configured to: when the hydrogen sulfide concentration exceeds the set value, start the backwashing device, backwash the filter with a set amount of gas, and adjust the backwashing flow rate according to the data collected by the dissolved oxygen coupled temperature probe.

[0010] Secondly, the above-mentioned operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration includes the following steps:

[0011] S1. The filter is started by inoculating the remaining sludge from the secondary sedimentation tank of the municipal wastewater treatment plant, and the raw wastewater input into the filter is the effluent from the aerobic tank of the secondary treatment of the municipal wastewater treatment plant.

[0012] S2. The raw sewage enters the lower part of the reaction zone through the buffer zone of the filter tank. The dissolved oxygen in the raw sewage is consumed by the aerobic bacteria here and enters the middle part of the reaction zone.

[0013] S3. In the middle of the reaction zone, the sulfur autotrophic denitrifying bacteria in the inoculated sludge consume the sulfur in the sulfur-containing filter media to generate sulfate, which reduces the nitrate in the original sewage to nitrogen. On the other hand, the remaining ammonia nitrogen in the original sewage is converted into nitrate under the action of anaerobic ammonia oxidizing bacteria, and the sewage enters the upper part of the reaction zone.

[0014] S4. In the upper part of the reaction zone, sulfate-reducing bacteria reduce the sulfate accumulated in the wastewater to hydrogen sulfide.

[0015] S5. Hydrogen sulfide is reduced to elemental sulfur in the oxygen-rich environment generated by gas-water backwashing, thereby reducing hydrogen sulfide and regenerating the sulfur source. The treated water is then discharged via overflow.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. This invention proposes a sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation filter based on a backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration. The filter is monitored in real time, and a backwashing strategy based on hydrogen sulfide and dissolved oxygen concentrations is implemented to control the gas-water ratio during the backwashing process. This precisely regulates the environment within the sulfur autotrophic denitrification filter, ensuring smooth sulfur autotrophic denitrification while coupling with anaerobic ammonia oxidation. Simultaneously, oxygen is used to oxidize the hydrogen sulfide, converting it into elemental sulfur, which continues to serve as the sulfur source to drive sulfur autotrophic denitrification and achieve sulfur source regeneration. This effectively reduces hydrogen sulfide content, ensuring that the gas discharged through the exhaust port is harmless to human health, while also mitigating pipeline corrosion.

[0018] 2. This invention proposes a backwashing strategy based on the regulation of hydrogen sulfide and dissolved oxygen concentrations, which achieves precise control of the operation of the backwashing air pump and backwashing water pump, adjusts the air-water ratio in the air-water backwashing process, and ensures that the autotrophic denitrification process and the anaerobic ammonia oxidation process proceed smoothly and simultaneously. It can maintain the hydrogen sulfide concentration in the reactor within a safe and suitable range, can be matched with the autotrophic denitrification filter system, save backwashing energy consumption, and reduce operating costs.

[0019] 3. The denitrification treatment scheme of the present invention combines sulfur autotrophic denitrification and anaerobic ammonia oxidation. Compared with the traditional heterotrophic denitrification scheme, the sludge production is reduced by 87%, realizing a low-carbon deep denitrification system without carbon source addition. Sulfur autotrophic denitrification removes nitrates from the influent, and anaerobic ammonia oxidation removes nitrites accumulated by sulfur autotrophic denitrification and ammonia nitrogen from the influent, reducing the aeration volume of the aerobic tank of the secondary biological treatment and saving sulfur source consumption and aeration energy consumption. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a schematic diagram of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on a backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration in Example 1.

[0022] The components include: 1. Water inlet tank; 2. Water inlet pipe; 3. Water inlet pump; 4. Water inlet; 5. Overflow device; 6. Water sample sampling port; 7. Filter media sampling port; 8. Uniform water distribution perforated plate; 9. Sulfur-containing filter media; 10. Vent; 11. Backwash water tank; 12. Backwash water inlet pipe; 13. Backwash water pump; 14. Backwash air pump; 15. Backwash air pipe; 16. Air-water mixing device; 17. Air-water inlet pipe; 18. Air-water inlet; 19. Dissolved oxygen coupled temperature probe; 20. Hydrogen sulfide probe; 21. Real-time monitoring and control system; 22. Drain outlet; 23. Drain pipe; 24. Drain pump; 25. Drain tank; 26. Cylindrical body; I. Reaction zone; II. Buffer zone. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] A sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on a backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration. The filter is equipped with a backwashing device at the bottom and sulfur-containing filter media is dispersed in the water. The outlet of the filter is equipped with a dissolved oxygen coupled temperature probe and a hydrogen sulfide probe, which are connected to a real-time monitoring and control system.

[0026] The sulfur-containing filter media serves as a carrier for the attachment and growth of sulfur-autotrophic denitrifying bacteria and anaerobic ammonia-oxidizing bacteria.

[0027] The real-time monitoring and control system is configured to: when the hydrogen sulfide concentration exceeds the set value, start the backwashing device, backwash the filter with a set amount of gas, and adjust the backwashing flow rate according to the data collected by the dissolved oxygen coupled temperature probe.

[0028] This setup allows for the coupling of anaerobic ammonia oxidation while ensuring the smooth progress of sulfur autotrophic denitrification. Simultaneously, the oxygen input from backwashing oxidizes sulfide, converting it into elemental sulfur, which continues to serve as a sulfur source to drive sulfur autotrophic denitrification and achieve sulfur source regeneration. This effectively reduces hydrogen sulfide content and saves on sulfur source consumption.

[0029] Optionally, the filter tank has an inlet at one end and an outlet at the other end opposite the inlet. Preferably, the filter tank is cylindrical, with the inlet at the bottom and the outlet at the top.

[0030] Optionally, the inlet is connected to an inlet pipe, and an inlet pump is installed on the inlet pipe to input the raw wastewater to be treated into the filter tank;

[0031] Optionally, the outlet is connected to an outlet pipe, and the outlet pipe is equipped with an outlet pump for discharging the treated wastewater in the filter tank; preferably, the outlet is equipped with an overflow device to prevent the discharge of sulfur-containing filter material.

[0032] Optionally, the backwashing device includes a backwashing air-water inlet pipe, which is equipped with an air-water mixing device for mixing the backwashing air and backwashing water before introducing them into the bottom of the filter tank. The air-water mixing device has two inlets, which are respectively connected to the backwashing air inlet pipe and the backwashing water inlet pipe. The flow rates of the backwashing air inlet pipe and the backwashing water inlet pipe are adjustable.

[0033] Optionally, a uniformly distributed water perforated plate with a fixed position is provided above the backwashing device in the filter tank. The uniformly distributed water perforated plate has through water holes with a diameter smaller than the particle size of the sulfur-containing filter material to prevent the sulfur-containing filter material from leaking below the uniformly distributed water perforated plate.

[0034] Optionally, the position between the inlet of the filter and the uniformly distributed perforated plate is a buffer zone to buffer the quality of the incoming water and reduce the impact of the incoming water on the filter system.

[0035] Optionally, the sulfur-containing filter media is composed of sulfur-containing filter media particles and quartz sand in a volume ratio of 4:1; wherein the particle size of the sulfur-containing filter media particles is 5-7 mm, and the particle size of the quartz sand is 6-10 mm.

[0036] The function of quartz sand is to support the sulfur-containing filter media. On the one hand, it ensures that the sulfur-containing filter media is evenly distributed throughout the entire height of the filter bed. On the other hand, because the particle size of quartz sand is larger than that of the sulfur-containing filter media, it can increase the porosity of the entire filter media layer, slow down or prevent the filter media layer from clogging, and ensure the normal flow of water.

[0037] Optionally, the area above the buffer zone of the filter is the lower part of the reaction zone, where dissolved oxygen in the raw wastewater is consumed by aerobic bacteria; the area above the lower part of the reaction zone is the middle part of the reaction zone, where sulfur autotrophic denitrifying bacteria gradually consume sulfur in the sulfur-containing filter media to generate sulfate and reduce nitrate to nitrogen gas, while anaerobic ammonia oxidizing bacteria convert ammonia nitrogen to nitrate; the area above the middle part of the reaction zone is the upper part of the reaction zone, where sulfate-reducing bacteria reduce sulfate to hydrogen sulfide, and hydrogen sulfide is reduced to elemental sulfur in an oxygen-rich environment.

[0038] Optionally, the elemental sulfur produced during the sulfur source regeneration process is in solid form, precipitating or adhering to the sulfur-containing filter media layer or quartz sand; the amount of regenerated elemental sulfur suspended in the water is small, and it will be directly utilized by sulfur autotrophic denitrifying bacteria for denitrification. Once consumed, it will basically not be discharged from the outlet.

[0039] Optionally, the filter tank is provided with multiple water sampling ports and filter media sampling ports arranged in the direction of water flow. These ports are used to sample wastewater and sulfur-containing filter media during the operation of the filter tank, so as to monitor the state of wastewater and sulfur-containing filter media at different locations and provide a basis for adjusting process parameters.

[0040] An operation method for the above-mentioned sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration includes the following steps:

[0041] S1. The filter is started by inoculating the remaining sludge from the secondary sedimentation tank of the municipal wastewater treatment plant, and the raw wastewater input into the filter is the effluent from the aerobic tank of the secondary treatment of the municipal wastewater treatment plant.

[0042] S2. The raw sewage enters the lower part of the reaction zone through the buffer zone of the filter tank. The dissolved oxygen in the raw sewage is consumed by the aerobic bacteria here and enters the middle part of the reaction zone.

[0043] S3. In the middle of the reaction zone, the sulfur autotrophic denitrifying bacteria in the inoculated sludge consume the sulfur in the sulfur-containing filter media to generate sulfate, which reduces the nitrate in the original sewage to nitrogen. On the other hand, the remaining ammonia nitrogen in the original sewage is converted into nitrate under the action of anaerobic ammonia oxidizing bacteria, and the sewage enters the upper part of the reaction zone.

[0044] S4. In the upper part of the reaction zone, sulfate-reducing bacteria reduce the sulfate accumulated in the wastewater to hydrogen sulfide.

[0045] S5. Hydrogen sulfide is reduced to elemental sulfur in the oxygen-rich environment generated by gas-water backwashing, thereby reducing hydrogen sulfide and regenerating the sulfur source. The treated water is then discharged via overflow.

[0046] Since hydrogen sulfide is converted into elemental sulfur through the regeneration process, the regenerated elemental sulfur solid can settle to the middle of the reaction zone with sulfur-containing filter media and / or quartz sand, and participate in the sulfur autotrophic denitrification process again, thereby reducing the amount of external sulfur source added.

[0047] Among them, aerobic bacteria, sulfur autotrophic denitrifying bacteria, anaerobic ammonia oxidizing bacteria and sulfate reducing bacteria come from the sludge (activated sludge) inoculated in S1. Since activated sludge is a complex system containing many kinds of bacteria, the required content of useful bacteria needs to be gradually increased during the process of domestication, cultivation and reproduction in a new environment to become a new sewage treatment system. In this invention, since there is sulfur-containing filter media in the system, sulfur autotrophic denitrifying bacteria will accumulate over a period of time.

[0048] The role of aerobic bacteria in S2 is to consume dissolved oxygen in the influent, creating a favorable anaerobic environment for sulfur autotrophic denitrification and anaerobic ammonia oxidation; at the same time, aerobic bacteria can also utilize dissolved oxygen to remove ammonia nitrogen from the influent.

[0049] The sulfur-autotrophic denitrifying bacteria in S3 are elemental sulfur-driven autotrophic denitrifying bacteria. Their function is to utilize thiosulfate (S2O3) in anaerobic or hypoxic environments. 2- -S), elemental sulfur (S) 0 -S), sulfides (S 2- Reduced sulfides such as -S act as electron donors to reduce NO. 2- -N and NO 3- -N generates N2, while simultaneously oxidizing sulfur to sulfate. During this process, nitrite gradually accumulates as an intermediate product.

[0050] The role of anaerobic ammonia oxidizing bacteria in S3 is to use the nitrite accumulated during sulfur autotrophic denitrification and the ammonia nitrogen in the influent as reaction substrates to convert them into nitrogen gas, thereby achieving the purpose of denitrification.

[0051] The sulfate-reducing bacteria in S4 also originate from sludge. Given suitable system environmental conditions, they will inevitably grow, making them a type of bacteria that will definitely grow in the system of this invention. They cannot be removed. Their function is to reduce the sulfate accumulated in the wastewater to hydrogen sulfide, a process that actually needs to be suppressed. On the other hand, sulfate-reducing bacteria can reduce the sulfate concentration in the effluent. However, current standards do not have strict requirements on sulfate discharge concentration, and the sulfate concentration discharged by such systems in actual application scenarios is not high, so this beneficial effect is not prominent.

[0052] Optionally, in S1, the raw wastewater contains an ammonia nitrogen concentration of 4.6±1.8 mg / L and a nitrate concentration of 22.3±8.2 mg / L.

[0053] Optionally, in S3, the nitrite accumulated during the sulfur autotrophic denitrification process and the remaining ammonia nitrogen in the original wastewater are removed by anaerobic ammonia oxidation to generate nitrate; the generated nitrate is then removed by the sulfur autotrophic denitrification process.

[0054] Optionally, in S5, when the hydrogen sulfide concentration is detected to exceed 15 ppm, a constant gas flow rate of 1000 ml / min is used for backwashing.

[0055] Optionally, based on the real-time temperature and the set suitable dissolved oxygen range of 0.1-0.7 mg / L for the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation process, the backwash water pump flow rate can be adjusted to perform air-water combined backwashing.

[0056] Optionally, the constant air volume for backwashing is determined based on the biomass concentration of the filter system. When the sludge concentration in the filter is less than 1500 mg / L, it is set to 500 ml / min; when the sludge concentration is between 1500 and 3000 mg / L, it is set to 1000 ml / min; and when the sludge concentration is greater than 3000 mg / L, it is set to 1500 ml / min.

[0057] Optionally, the backwashing process can be stopped when the hydrogen sulfide concentration drops below 8 ppm.

[0058] Under this backwashing strategy, most of the hydrogen sulfide can be oxidized to elemental sulfur in time, continuing to drive sulfur autotrophic denitrification. A small portion of hydrogen sulfide will be further oxidized to sulfate due to excess oxygen, which will remain in the treated water and be discharged from the system through the drain outlet.

[0059] Example 1

[0060] like Figure 1 As shown, a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter is constructed based on a backwashing strategy to reduce hydrogen sulfide and regenerate the sulfur source. The filter body is a cylindrical tube 26 made of plexiglass, with an inner diameter of 10.8 cm and an outer diameter of 12 cm.

[0061] A uniformly distributed water perforated plate 8 is installed at the lower part of the cylindrical body 26. The uniformly distributed water perforated plate 8 also serves as a filter media support, and the perforation diameter is 3mm.

[0062] Below the uniformly distributed perforated plate 8 is buffer zone II, which has a height of 11cm and an effective volume of 1L. Above the uniformly distributed perforated plate 8 is reaction zone I, which has a height of 66cm and an effective volume of 6L. Reaction zone I is filled with 4.8L of sulfur-containing filter media 9, which consists of sulfur-containing filter media particles and quartz sand in a volume ratio of 4:1. The sulfur-containing filter media particles have a particle size of 6mm, and the quartz sand has a particle size of 8mm.

[0063] Water sampling ports 6 and filter media sampling ports 7 are evenly distributed on the wall of the cylindrical body 26 in the height direction. The distance between adjacent water sampling ports 6 is 11cm, and the distance between adjacent filter media sampling ports 7 is 11cm.

[0064] A water inlet 4 is provided on one side of the bottom of the cylindrical body 26. The water inlet 4 is connected to the water inlet bucket 1 through the water inlet pipe 2. A water pump 3 is provided on the water inlet pipe 2.

[0065] On the other side of the bottom of the cylindrical body 26, there is an air inlet 18, which is connected to the backwashing device. The air inlet 18 is connected to the water and air distribution plate, which is used to evenly discharge the air and water delivered by the backwashing device and distribute them evenly inside the cylindrical body 26.

[0066] The backwashing device includes an air-water pipe 17 connected to the air inlet 18, and the other end of the air-water pipe 17 is connected to the output end of the air-water mixing device 16. The air-water mixing device 16 has two input ends; one input end is connected to the backwashing air pipe 15, which is connected to the backwashing air pump 14; the other input end is connected to the backwashing water inlet pipe 12, which is connected to the backwashing water tank 11. A backwashing water pump 13 is installed on the backwashing water inlet pipe 12.

[0067] An overflow device 5 is installed on the top of the cylindrical body 26. A drain outlet 22 is provided on the overflow side of the overflow device 5. The drain outlet 22 is connected to the drain bucket 25 through a drain pipe 23. A drain pump 24 is provided on the drain pipe 23.

[0068] The top of the overflow device 5 is provided with an exhaust port 10 for discharging the gas generated in the cylindrical body 26.

[0069] At the upper part of reaction zone I, below the overflow device 5, a hydrogen sulfide probe 20 and a dissolved oxygen coupled temperature probe 19 are respectively installed. The hydrogen sulfide probe 20 and the dissolved oxygen coupled temperature probe 19 are connected to the real-time monitoring and control system 21. The real-time monitoring and control system 21 is connected to the backwash air pump 14 and the backwash water pump 13, and can adjust the flow rate of the backwash air pump 14 and the backwash water pump 13.

[0070] The operation method of this embodiment includes the following steps:

[0071] S1. The cylindrical body 26 of the filter is inoculated with the remaining sludge from the secondary sedimentation tank of the municipal wastewater treatment plant to start the process. The inlet tank 1 contains the effluent from the aerobic tank of the secondary treatment of the municipal wastewater treatment plant, which mainly contains ammonia nitrogen (concentration of 4.6±1.8mg / L) and nitrate (concentration of 22.3±8.2mg / L), and serves as the raw sewage input to the filter inlet 4.

[0072] S2. The raw sewage enters the lower part of reaction zone I through the buffer zone II of the filter tank. The dissolved oxygen in the raw sewage is consumed by the aerobic bacteria here and enters the middle part of reaction zone I.

[0073] S3. In the middle of reaction zone I, the sulfur autotrophic denitrifying bacteria in the inoculated sludge consume the sulfur in the sulfur-containing filter media 9 to generate sulfate, which reduces the nitrate in the original sewage to nitrogen. On the other hand, the remaining ammonia nitrogen in the original sewage is converted into nitrate under the action of anaerobic ammonia oxidizing bacteria, and the sewage enters the upper part of reaction zone I.

[0074] S4. In the upper part of reaction zone I, sulfate-reducing bacteria reduce the sulfate accumulated in the wastewater to hydrogen sulfide.

[0075] S5. Hydrogen sulfide is reduced to elemental sulfur in the oxygen-rich environment generated by gas-water backwashing, thereby reducing hydrogen sulfide and regenerating the sulfur source. The treated water is then discharged via overflow.

[0076] In S5, when the real-time monitoring and control system 21 detects that the hydrogen sulfide concentration in the upper part of reaction zone I exceeds 15 ppm through the hydrogen sulfide probe 20 and the dissolved oxygen coupled temperature probe 19, it starts the backwash gas pump 14 to perform a constant gas flow rate of 1000 ml / min for backwashing.

[0077] Based on the real-time temperature measured by the dissolved oxygen coupled temperature probe 19 and the set suitable dissolved oxygen range of 0.1-0.7 mg / L for the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation process, the flow rate of the backwash water pump 13 is adjusted to carry out air-water combined backwashing.

[0078] Specifically, the constant air volume for backwashing is determined based on the biomass concentration of the filter system. When the sludge concentration in the cylindrical shell 26 is less than 1500 mg / L, it is set to 500 ml / min; when the sludge concentration in the cylindrical shell 26 is between 1500 and 3000 mg / L, it is set to 1000 ml / min; and when the sludge concentration in the cylindrical shell 26 is higher than 3000 mg / L, it is set to 1500 ml / min. The specific value can also be adjusted according to actual operating experience.

[0079] When the hydrogen sulfide probe 20 detects that the hydrogen sulfide concentration has dropped to below 8 ppm, both the backwash water pump 13 and the backwash air pump 14 stop operating. Under this backwash strategy, most of the hydrogen sulfide can be oxidized to elemental sulfur in time, continuing to drive sulfur autotrophic denitrification. A small portion of the hydrogen sulfide will be further oxidized to sulfate due to excess oxygen, which will remain in the treated water and be discharged from the system through the drain outlet 22.

[0080] The wastewater purification effect of this embodiment is as follows: when the raw wastewater contains ammonia nitrogen concentration of 4.6±1.8mg / L and nitrate concentration of 22.3±8.2mg / L, the hydrogen sulfide concentration after treatment is less than 8ppm, the effluent ammonia nitrogen is less than 0.5mg / L, the nitrate concentration is less than 5mg / L, and the hydraulic retention time can reach 2 hours; the consumption of sulfur in the sulfur-containing filter media is related to the influent load. Under the influent concentration given above, it should be replenished once every 8-10 months. The replenishment amount is determined based on the observed decrease in filter bed height, and the overall filter bed height should be kept relatively consistent.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An operation method for a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on a backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration, characterized in that: A backwashing device is installed below the filter tank, and sulfur-containing filter media is dispersed in the water in the filter tank; a dissolved oxygen coupled temperature probe and a hydrogen sulfide probe are installed at the outlet of the filter tank, and the dissolved oxygen coupled temperature probe and the hydrogen sulfide probe are connected to a real-time monitoring and control system. The sulfur-containing filter media serves as a carrier for the attachment and growth of sulfur-autotrophic denitrifying bacteria and anaerobic ammonia-oxidizing bacteria. The real-time monitoring and control system is configured to: when the hydrogen sulfide concentration exceeds the set value, start the backwashing device, backwash the filter with a set amount of gas, and adjust the backwashing flow rate according to the data collected by the dissolved oxygen coupled temperature probe; The operation method includes the following steps: S1. The filter is started by inoculating the remaining sludge from the secondary sedimentation tank of the municipal wastewater treatment plant, and the raw wastewater input into the filter is the effluent from the aerobic tank of the secondary treatment of the municipal wastewater treatment plant. S2. The raw sewage enters the lower part of the reaction zone through the buffer zone of the filter tank. The dissolved oxygen in the raw sewage is consumed by the aerobic bacteria here and enters the middle part of the reaction zone. S3. In the middle of the reaction zone, the sulfur autotrophic denitrifying bacteria in the inoculated sludge consume the sulfur in the sulfur-containing filter media to generate sulfate, which reduces the nitrate in the original sewage to nitrogen. On the other hand, the remaining ammonia nitrogen in the original sewage is converted into nitrate under the action of anaerobic ammonia oxidizing bacteria, and the sewage enters the upper part of the reaction zone. S4. In the upper part of the reaction zone, sulfate-reducing bacteria reduce the sulfate accumulated in the wastewater to hydrogen sulfide. S5. Hydrogen sulfide is oxidized to elemental sulfur in the oxygen-rich environment generated by gas-water backwashing, thereby reducing hydrogen sulfide and regenerating the sulfur source. The treated water is discharged through overflow. In S5, when the hydrogen sulfide concentration is detected to exceed 15 ppm, a constant gas backwash is performed.

2. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, The filter tank has an inlet at one end and an outlet at the other end opposite the inlet.

3. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, The inlet is connected to an inlet pipe, which is equipped with an inlet pump for feeding raw wastewater into the filter tank.

4. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, The outlet is connected to an outlet pipe, which is equipped with an outlet pump for discharging the treated wastewater from the filter tank.

5. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 4, characterized in that, The outlet is equipped with an overflow device to prevent sulfur-containing filter media from being discharged.

6. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, The backwashing device includes a backwashing air-water inlet pipe, and an air-water mixing device is installed on the backwashing air-water inlet pipe to mix the backwashing air and backwashing water and then introduce them into the bottom of the filter tank.

7. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, Above the backwashing device in the filter tank, there is a fixed-position uniformly distributed water perforated plate with through-holes. The diameter of the water perforated plate is smaller than the particle size of the sulfur-containing filter material.

8. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, The sulfur-containing filter media consists of sulfur-containing filter media particles and quartz sand in a volume ratio of 4:1; wherein the particle size of the sulfur-containing filter media particles is 5~7mm, and the particle size of the quartz sand is 6~10mm.

9. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, Above the buffer zone of the filter is the lower part of the reaction zone, where dissolved oxygen in the raw wastewater is consumed by aerobic bacteria. Above the lower part of the reaction zone is the middle part of the reaction zone, where sulfur autotrophic denitrifying bacteria gradually consume sulfur in the sulfur-containing filter media to generate sulfate and reduce nitrate to nitrogen. At the same time, anaerobic ammonia oxidizing bacteria convert ammonia nitrogen to nitrate here. Above the middle part of the reaction zone is the upper part of the reaction zone, where sulfate-reducing bacteria reduce sulfate to hydrogen sulfide. Hydrogen sulfide is oxidized to elemental sulfur in an oxygen-rich environment.

10. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, In S1, the raw wastewater contained ammonia nitrogen at a concentration of 4.6 ± 1.8 mg / L and nitrate at a concentration of 22.3 ± 8.2 mg / L.

11. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, In S3, the nitrite accumulated during the sulfur autotrophic denitrification process and the remaining ammonia nitrogen in the original wastewater are removed by anaerobic ammonia oxidation to generate nitrate. The generated nitrates are then removed by the sulfur autotrophic denitrification process.

12. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, characterized in that, Based on the real-time temperature and the set suitable dissolved oxygen range of 0.1-0.7 mg / L for the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation process, the backwash water pump flow rate is adjusted to carry out air-water combined backwashing.

13. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, wherein the constant gas flow rate for gas backwashing is determined based on the biomass concentration of the filter system. When the sludge concentration in the filter is less than 1500 mg / L, it is set to 500 ml / min; when the sludge concentration is between 1500-3000 mg / L, it is set to 1000 ml / min; and when the sludge concentration is higher than 3000 mg / L, it is set to 1500 ml / min.

14. The operation method of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation filter based on backwashing strategy to achieve hydrogen sulfide reduction and sulfur source regeneration as described in claim 1, wherein the backwashing process is stopped when the hydrogen sulfide concentration drops below 8 ppm.

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