Deep denitrification system device and denitrification process for high-salinity wastewater

Abstract

The invention discloses a deep denitrification system device for high-salinity wastewater, which comprises a nitrification biofilter and a denitrification biofilter, a water inlet of the nitrification biofilter is connected with a water inlet pump, a gas inlet of the nitrification biofilter is connected with a gas inlet pump, and a nitrification biofilm carrier is added in the nitrification biofilter. The nitrification biological filter and the denitrification biological filter are directly arranged in the same biological filter. The denitrification biofilter is provided with a water outlet, and solid particles for driving denitrification nitrogen removal are filled in the denitrification biofilter. When being used for treating high-salinity wastewater, the system device and the process have the advantages of high adaptability, high salt tolerance, no need of accurate control of aeration, capability of resisting impact of organic load, small influence of dissolved oxygen fluctuation and high denitrification efficiency, and the total nitrogen content in effluent can meet the emission standard.

Description

Technical Field

[0001] The present invention relates to the technical field of biological sewage treatment for nitrogen removal, and particularly to a deep nitrogen removal system device and process for high-salinity wastewater Background Art

[0002] High-salinity wastewater mainly comes from industries such as seawater desalination, seawater aquaculture, landfill leachate, leather and tanning, pharmaceuticals, textile printing and dyeing, electroplating, and metal processing. Such wastewater contains high concentrations of salts such as sodium chloride and sulfates, resulting in increased osmotic pressure and inhibition of microbial activity, posing challenges to conventional biological nitrogen removal processes. In addition, nitrogen pollutants such as ammonia nitrogen, nitrates, and nitrites are often present in high-salinity wastewater. If directly discharged, it will cause eutrophication and damage the water body ecological balance. Therefore, achieving efficient nitrogen removal in a high-salt environment has become a technical problem in the field of wastewater treatment. The efficiency of traditional nitrification-denitrification processes significantly decreases in a high-salt environment, and it is necessary to develop salt-tolerant microorganisms or adjust reaction conditions to improve nitrogen removal effects

[0003] Traditional nitrification-denitrification can effectively remove nitrogen, but traditional nitrification-denitrification needs to separate nitrification and denitrification in two different reactors to avoid the impact of dissolved oxygen in the nitrification part on denitrification, and it is necessary to add organic carbon sources as electron donors, which may cause secondary pollution. Therefore, based on traditional nitrification-denitrification nitrogen removal, personnel in this technical field have developed various nitrogen removal combined processes such as short-cut nitrification-short-cut autotrophic / heterotrophic denitrification, short-cut simultaneous nitrification-denitrification-autotrophic / heterotrophic denitrification, and simultaneous nitrification-denitrification-autotrophic / heterotrophic denitrification in the same reactor. However, these combined processes also have the following problems: (1) The short-cut nitrification process section requires strict DO control and precise aeration. (2) The denitrification nitrogen removal performance is easily affected by dissolved oxygen, resulting in low denitrification nitrogen removal efficiency Summary of the Invention

[0004] In view of the above, the present invention provides a deep nitrogen removal system device and process for high-salinity wastewater to solve the problems raised in the above background art, with strong adaptability, strong salt tolerance, no need for precise aeration, resistance to organic load shock, low dissolved oxygen impact, high nitrogen removal efficiency, and the total nitrogen in the effluent meeting the discharge standards

[0005] To achieve the above invention purpose, the technical solution adopted by the present invention is as follows: A deep nitrogen removal system device for high-salinity wastewater, characterized in that it includes a nitrification biological filter and a denitrification biological filter. The inlet of the nitrification biological filter is connected to a feed water pump, the air inlet of the nitrification biological filter is connected to an air inlet pump, and a nitrification biological membrane carrier is added in the nitrification biological filter. The nitrification biological filter and the denitrification biological filter are directly in the same biological filter. The denitrification biological filter is provided with an outlet, and solid particles for driving denitrification nitrogen removal are filled in the denitrification biological filter

[0006] Furthermore, the nitrification biological filter includes a biofilm carrier filler, a water inlet, an air inlet, a metering pump, an aerator, a connecting pipe, and a sampling port. The metering pump is located at the top of the nitrification biological filter. The aerator is located below the metering pump.

[0007] The denitrification biological filter includes a driving denitrification and nitrogen removal solid filler and a water outlet. The water outlet is connected to the water outlet tank through a pipeline.

[0008] The sampling port is located at different heights of the reactor. The sampling port is connected to a tee, which can be used for sampling, air intake, and water intake.

[0009] The filler of the nitrification biofilm filter is a block-shaped suspended filler with a large specific surface area.

[0010] A deep nitrogen removal process for high-salinity wastewater includes the following steps:

[0011] (1) Nitrification reaction: The high-salinity wastewater enters the short-cut simultaneous nitrification and denitrification reactor through a feed pump for short-cut nitrification reaction and denitrification reaction; non-precise continuous timed aeration is adopted in the short-cut simultaneous nitrification and denitrification reactor, and the hydraulic retention time is controlled at 4-8 h. In the short-cut simultaneous nitrification and denitrification reactor, denitrifying microorganisms can use the organic matter in the wastewater to reduce part of the nitrate nitrogen and part of the nitrite nitrogen to nitrogen gas. The remaining wastewater containing nitrate nitrogen and nitrite nitrogen directly flows by gravity to the denitrification biological filter;

[0012] (2) Denitrification reaction: The denitrifying bacteria in the anaerobic denitrification biological filter use the electron donor provided by the biological carrier to reduce the nitrite nitrogen and nitrate nitrogen in the effluent of the short-cut simultaneous nitrification and denitrification reactor; short-cut denitrification and complete denitrification are carried out to gradually reduce the nitrite and nitrate in the effluent of the nitrification biological filter to nitrogen gas.

[0013] (3) Wastewater discharge: The water outlet is located below the anaerobic denitrification section. In the system, the water flows from top to bottom. The water outlet is connected to a pipeline, and the lifting height is between 3-10 cm from the top. The water flows from top to bottom through the short-cut simultaneous nitrification and denitrification reactor and the anaerobic denitrification biological filter, and finally passes through the outlet pipeline for up-to-standard discharge of the effluent.

[0014] In steps (1) and (2), the original salinity concentration of the high-salinity wastewater is 25 g / L - 35 g / L.

[0015] According to (1), (2), and (3), the hydraulic retention time in the high-efficiency nitrogen removal biological filter is 4-8 hours, and the reaction temperature is 25-35 °C.

[0016] According to the deep nitrogen removal process for high-salinity wastewater described in claim 1, the filler of the nitrification biofilm filter is a block-shaped suspended filler with a large specific surface area

[0017] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0018] (1) In the short-cut nitrification process section of the present invention, non-precise continuous aeration is adopted, with high salt tolerance. Even if excessive aeration or insufficient carbon source causes the short-cut nitrification effluent to contain nitrate nitrogen, it has no impact on the overall denitrification performance of the system.

[0019] (2) The present invention uses salinity to inhibit nitrite-oxidizing bacteria to form a short-cut nitrification reaction, which can achieve the purpose of nitrite accumulation; while salinity has the effect of increasing the abundance of ammonia-oxidizing bacteria, enabling efficient nitrite accumulation.

[0020] (3) In the present invention, ammonia-oxidizing bacteria are added in the form of cubic suspended fillers with a large specific surface area in the high-efficiency denitrifying aerobic reactor to enhance the anti-shock load of ammonia-oxidizing bacteria to the dissolved oxygen and organic carbon source in the influent water.

[0021] (4) In the high-efficiency denitrifying anaerobic reactor of the present invention, denitrifying bacteria can simultaneously utilize organic carbon sources and drive denitrifying solids to carry out short-cut denitrification to generate nitrite nitrogen, and the nitrite nitrogen produced by short-cut nitrification is further reduced to nitrogen gas, improving the denitrification load efficiency and achieving the purpose of deep and efficient denitrification of the system;

[0022] (5) An outlet water tank is arranged at the end of the present invention to further ensure the water level height and guarantee sufficient hydraulic retention time.

[0023] (6) The deep denitrification process of the present invention adopts corrosion-resistant pp material components, which can extend the service life of the equipment. Description of the Drawings

[0024] Figure 1 It is a deep denitrification system device and denitrification process for high-salinity wastewater of the present application.

[0025] In the figure, 1. Nitrification biofilm filter; 1.1. Influent water pump; 1.2. Influent water tank; 1.3. Aerator; 1.4 Three-way; 1.5 Sampling port; 1.6 Aerobic biofilm carrier filler, 2. Denitrification biofilm filter; 2.1 Sampling port; 2.2 Sampling port; 2.3 Outlet; 2.4 Bottom support; 2.5 Outlet pipe; 2.6 Outlet water tank. Detailed Embodiments

[0026] To make the objectives, technical solutions and advantages of the present invention clearer, the following preferred embodiments are given to further elaborate on the present invention. However, it should be noted that many details listed in the specification are only for enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be realized even without these specific details.

[0027] As Figure 1 shown, a deep denitrification system device for high-salinity wastewater is characterized in that it includes a nitrifying biological filter 1 and a denitrifying biological filter 2. The water inlet of the nitrifying biological filter 1 is sequentially connected to a feed water pump 1.1, and the feed water pump is connected to a feed water tank 1.2. The air inlet of the nitrifying biological filter is connected to an aerator 1.3. There is a tee 1.4 between the aerator and the reactor. A nitrifying biological membrane carrier 1.6 is added in the nitrifying biological filter, and there is a terminal sampling port 1.5 in the aerobic nitrification section. The nitrifying biological filter 1 and the denitrifying biological filter 2 are directly in the same biological filter. The denitrifying biological filter is provided with a water outlet 2.1, a water outlet 2.3, a water outlet pipe 2.5, a bottom support 2.4, a water outlet tank 2.6, and a solid particle 2.7 for driving denitrification and nitrogen removal is filled in the denitrifying biological filter.

[0028] Further, the nitrifying biological filter 1 includes a biological membrane carrier filler 1.6, a water inlet, a metering pump 1.1, an aerator 1.3, a connecting pipe, sampling ports 1.4 and 1.5, and a water outlet tank 2.6. The metering pump is located at the top of the nitrifying biological filter. The aerator is located below the metering pump.

[0029] The denitrifying biological filter includes a solid filler 2.7 for driving denitrification and nitrogen removal and a water outlet 2.3. The water outlet pipe 2.5 is connected to the water outlet tank 2.6.

[0030] The sampling ports are located at different heights of the reactor. The sampling ports are connected to tees and can be used for sampling, air intake, and water intake.

[0031] The filler of the nitrifying biological membrane filter is a block-shaped suspended filler with a large specific surface area

[0032] A deep denitrification process for high-salinity wastewater includes the following steps:

[0033] (1) Nitrification reaction: The high-salinity wastewater enters a short-cut simultaneous nitrification and denitrification reactor through a feed water pump for short-cut nitrification reaction and denitrification reaction; non-precise continuous timed aeration is adopted in the short-cut simultaneous nitrification and denitrification reactor, and the hydraulic retention time is controlled at 4 - 8 h. In the short-cut simultaneous nitrification and denitrification reactor, denitrifying microorganisms can use the organic matter in the wastewater to reduce part of the nitrate nitrogen and part of the nitrite nitrogen to nitrogen gas. The remaining wastewater containing nitrate nitrogen and nitrite nitrogen directly flows by gravity to the denitrifying biological filter;

[0034] (2) Denitrification reaction: The denitrifying bacteria in the anaerobic denitrifying biological filter use the electron donor provided by the biological carrier to reduce the nitrite nitrogen and nitrate nitrogen in the effluent of the short-cut simultaneous nitrification and denitrification reactor; short-cut denitrification and complete denitrification are carried out to gradually reduce the nitrite and nitrate in the effluent of the nitrifying biological filter to nitrogen gas.

[0035] (3) Wastewater discharge: The water outlet is located below the anaerobic denitrification section. In the system, the water flows from top to bottom. The water outlet is connected to a pipeline, and the lifting height is between 3 - 10 cm from the top. The water flows from top to bottom through the shortcut simultaneous nitrification and denitrification reactor and the anaerobic denitrification biological filter, and finally is discharged up to the standard through the effluent pipeline.

[0036] In steps (1) and (2), for the high-salinity wastewater, the original salinity concentration is 25 g / L - 35 g / L.

[0037] According to (1), (2) and (3), the hydraulic retention time in the high-efficiency denitrification biological filter is 4 - 8 hours, and the reaction temperature is 25 - 35 °C.

[0038] According to a deep denitrification process for high-salinity wastewater described in claim 1, characterized in that the filler of the nitrification biological membrane filter is a block-shaped suspended filler with a large specific surface area.

[0039] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0040] (1) In the shortcut nitrification process section of the present invention, non-precise continuous aeration is adopted, with high salt tolerance. Even if excessive aeration or insufficient carbon source causes the shortcut nitrification effluent to contain nitrate nitrogen, it has no impact on the overall denitrification performance of the system.

[0041] (2) The present invention uses salinity to inhibit nitrite-oxidizing bacteria to form a shortcut nitrification reaction, which can achieve the purpose of nitrite accumulation; while salinity has the effect of increasing the abundance of ammonia-oxidizing bacteria, enabling efficient nitrite accumulation.

[0042] (3) In the present invention, the ammonia-oxidizing bacteria are added in the form of block-shaped suspended fillers with a large specific surface area in the high-efficiency denitrification aerobic reactor to enhance the anti-shock load of the ammonia-oxidizing bacteria to the dissolved oxygen and organic carbon source in the influent water.

[0043] (4) In the high-efficiency denitrification anaerobic reactor of the present invention, denitrifying bacteria can simultaneously utilize the organic carbon source and drive the denitrifying solid to carry out shortcut denitrification to generate nitrite nitrogen, and the nitrite nitrogen produced by shortcut nitrification is further reduced to nitrogen gas, improving the denitrification load efficiency and achieving the purpose of deep and efficient denitrification of the system;

[0044] (5) A water outlet tank is arranged at the end of the present invention to further ensure the water level height and guarantee sufficient hydraulic retention time.

[0045] (6) The deep denitrification process of the present invention adopts corrosion-resistant pp material components, which can extend the service life of the equipment.

[0046] Example 1 Treatment of seawater aquaculture tail water

[0047] (1) The original high-salinity wastewater is directly pumped into the nitrifying biofilm reactor 1 by the feed water pump 1.1.

[0048] (2) The high-salinity mariculture wastewater flows into the nitrifying biofilm reactor 1, and the aerator 1.3 maintains stable dissolved oxygen. Short-cut nitrification occurs to ammonia nitrogen, generating nitrite. The dissolved oxygen is controlled between 6 mg / L. The high-salinity wastewater containing nitrite flows by gravity through the anaerobic denitrifying biological filter 2 for anaerobic autotrophic denitrification and nitrogen removal, and the effluent flows through the outlet 2.3 and the outlet pipe 2.5 into the outlet water tank 2.6. The hydraulic retention time is maintained at 6 h, the reaction temperature is 25°C ± 2, the aerobic nitrifying suspended packing 1.7 is square-shaped, and the addition amount is to fill the nitrification section; the anaerobic denitrification section includes the autotrophic denitrifying solid packing 2.7.

[0049] In the nitrification section and the denitrification section, microorganisms can utilize the organic matter in the tail water to carry out nitrate reduction. Short-cut nitrification coupled with autotrophic / heterotrophic denitrification is formed.

[0050] Experiments show that when the influent ammonia nitrogen is 18 - 25 mg / L, the nitrate nitrogen is 9 - 11 mg / L, and the C / N is 1.2, the treatment effects of the effluent total nitrogen and COD meet the first-class discharge standard of "Guangxi Zhuang Autonomous Region Local Standard: Discharge Standard for Mariculture Tail Water" (DB45 / T 2841 - 2024).

[0051] The above are only the preferred implementation schemes of the present invention. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A system device for deep denitrification of high-salinity wastewater, characterized in that, Comprising: A nitrifying biological filter and a denitrifying biological filter. The water inlet of the nitrifying biological filter is connected to a water inlet pump, the air inlet of the nitrifying biological filter is connected to an air inlet pump, and a nitrifying biological membrane carrier is added into the nitrifying biological filter. The nitrifying biological filter and the denitrifying biological filter are directly in the same biological filter. The denitrifying biological filter is provided with a water outlet, and solid particles for driving denitrifying nitrogen removal are filled in the denitrifying biological filter.

2. The system device for deep denitrification of high-salinity wastewater according to claim 1 of the patent, characterized in that, The nitrifying biological filter comprises a biological membrane carrier filler, a water inlet, an air inlet, a metering pump, an aerator, a connecting pipe, and a sampling port. The metering pump is located at the top of the nitrifying biological filter. The aerator is located below the metering pump.

3. A system device for deep denitrification of high-salinity wastewater according to claim 1 of the patent, characterized in that, The denitrifying biological filter comprises a solid filler for driving denitrifying nitrogen removal and a water outlet. The water outlet is connected to a water outlet tank through a pipeline.

4. A system device for deep denitrification of high-salinity wastewater according to claim 1 of the patent, characterized in that, The sampling port is located at different heights of the reactor. The sampling port is connected to a tee, and can be used for sampling, air intake, and water intake.

5. A deep denitrification process for high-salinity wastewater, characterized in that, Including the following steps: (1) Nitrification reaction: The high-salinity wastewater enters the shortcut simultaneous nitrification and denitrification reactor through the water inlet pump for shortcut nitrification reaction and denitrification reaction; non-precise continuous aeration is adopted in the shortcut simultaneous nitrification and denitrification reactor, and the hydraulic retention time is controlled to be 4-8 h. In the shortcut simultaneous nitrification and denitrification reactor, denitrifying microorganisms can utilize the organic matter in the wastewater to reduce part of the nitrate nitrogen and part of the nitrite nitrogen to nitrogen gas. The remaining wastewater containing nitrate nitrogen and nitrite nitrogen directly flows to the denitrifying biological filter by gravity. (2) Denitrification reaction: The denitrifying bacteria in the anaerobic denitrifying biological filter utilize the electron donor provided by the biological carrier to reduce the nitrite nitrogen and nitrate nitrogen in the effluent of the shortcut simultaneous nitrification and denitrification reactor; shortcut denitrification and complete denitrification are carried out to gradually reduce the nitrite and nitrate in the effluent of the nitrifying biological filter to nitrogen gas. (3) Wastewater discharge: The water outlet is located below the anaerobic denitrification section. In the system, the water flows from top to bottom. The water outlet is connected to a pipeline, and the lifting height is between 3-10 cm from the top. The water flows through the shortcut simultaneous nitrification and denitrification reactor and the anaerobic denitrifying biological filter from top to bottom, and finally passes through the water outlet pipeline for discharging the qualified water.

6. The deep denitrification process for high-salinity wastewater according to claim 5, characterized in that , the high-salinity wastewater, the original salinity concentration is 25 g / L - 35 g / L.

7. The deep denitrification process for highly saline wastewater according to claim 6, characterized in that , the hydraulic retention time in the high-efficiency nitrogen-removing biological filter is 4-8 hours, and the reaction temperature is 25-35 °C.

8. The deep denitrification process for high-salinity wastewater according to claim 1, characterized in that , the filler of the nitrifying biological membrane filter is a block-shaped suspended filler with a large specific surface area.

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