Gas-liquid two-phase biological denitrification device

Abstract

This invention belongs to the field of aquaculture equipment, specifically relating to a gas-liquid two-phase biological denitrification device. The gas-liquid two-phase biological denitrification device includes a shell, a water spraying device, and multiple packing grids. The shell has a cavity, and the water spraying device and the multiple packing grids are all installed in the cavity along the X-axis. One end of each packing grid is installed on a side wall of the shell, and a gap is provided between the other end and the side wall of the shell. The upper surface of each packing grid and the gap are filled with biological packing material, which is used for denitrification treatment of the effluent. The packing grid at the lowest point along the Y-axis forms a biological nitrification tank with the shell, which is used for further denitrification treatment of the effluent. The denitrification device of this invention enables multiple deep denitrification treatments of the effluent, improving the denitrification efficiency.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture equipment technology, specifically relating to a gas-liquid two-phase biological denitrification device. Background Technology

[0002] Recirculating aquaculture (RAA) is a method of aquaculture that utilizes water treatment technology to purify and reuse the aquaculture water. It offers advantages such as water conservation, energy saving and emission reduction, and small footprint, making it a future direction for aquaculture development. Currently, in RIA systems, microbial nitrification is generally used as the primary means of removing total nitrogen from cultured organisms. However, existing microbial nitrification systems require a large chamber, resulting in the nitrification chamber occupying one-third to one-half of the total volume of the RIA system, making it inconvenient to install and use other equipment. Furthermore, while existing nitrification chambers occupy a large space, their nitrogen removal capacity is weak and their nitrogen removal efficiency is low. Moreover, in RIA systems, as aquaculture progresses, the concentration of carbon dioxide in the water gradually increases. Since carbon dioxide is highly soluble in oxygen, adding oxygen to the circulating water becomes increasingly difficult in the later stages of aquaculture. Summary of the Invention

[0003] To address the technical problems of weak denitrification capacity and low denitrification efficiency in nitrification chambers of recirculating aquaculture systems, this invention provides a gas-liquid two-phase biological denitrification device.

[0004] This invention is achieved using the following technical solution: a gas-liquid two-phase biological denitrification device, comprising a shell, a water spraying device, and multiple packing grids. The shell has a cavity, with the length direction of the shell defined as the X-axis, the height direction as the Y-axis, and the width direction as the Z-axis. The water spraying device is installed in the cavity along the X-axis and above the multiple packing grids. The water spraying device is used to spray the wastewater to be treated onto the packing grids. The multiple packing grids are installed at intervals along the Y-axis in the cavity. One end of each packing grid is installed on one side wall of the shell, and a gap is provided between the other end of each packing grid and the opposite side wall of the shell. Each packing grid has multiple through holes, and each packing grid... The upper surface and the gaps are filled with biological packing material, which is used to denitrify the effluent. The effluent after denitrification by the biological packing material on the previous packing grid flows through the gaps or through holes to the next packing grid. The shell is divided into a left side wall and a right side wall on two side walls along the X-axis. Two adjacent packing grids are alternately fixed to the left side wall and the right side wall of the shell. The packing grid at the lowest point in the Y-axis direction forms a biological nitrification tank with the shell. The effluent to be treated sprayed by the water spraying device passes through each packing grid in sequence for denitrification and then enters the biological nitrification tank. The biological nitrification tank is used to further denitrify the effluent after denitrification by the packing grids.

[0005] As a further improvement of the present invention, a filtration device is installed in the biological nitrification tank, which divides the biological nitrification tank into a nitrification zone and a tailwater collection zone. The nitrification zone is used to perform secondary denitrification on the tailwater after it has been denitrified by multiple packing grids. The filtration device is used to filter the tailwater after secondary denitrification in the nitrification zone, and the filtered tailwater enters the tailwater collection zone.

[0006] As a further improvement of the present invention, the filtration device is composed of multiple filter screens, which are installed sequentially in the biological nitrification tank along the X-axis direction, and the pore size of the filter screens gradually decreases from the nitrification zone to the effluent collection zone.

[0007] As a further improvement of the present invention, the water spraying device includes a spray pipe and a plurality of nozzles, the plurality of nozzles being respectively connected to the spray pipe, and the plurality of nozzles being respectively directed toward the packing grid located below the spray pipe.

[0008] As a further improvement of the present invention, the packing grid is provided with an angle α with the X-axis direction, and the range of the angle α is 0°≤α≤30°.

[0009] As a further improvement of the present invention, the spacing between any two adjacent packing grids in the Y-axis direction is equal.

[0010] As a further improvement of the present invention, the length of the gap in the X-axis direction is one-tenth to one-fifteenth of the length of the packing grid in the X-axis direction.

[0011] As a further improvement of the present invention, the biological packing material is biological ceramic granules.

[0012] As a further improvement of the present invention, a water outlet pipe is also installed on the shell, and the water outlet pipe is connected to the tailwater collection area.

[0013] As a further improvement of the present invention, the gas-liquid two-phase biological denitrification device also includes a water pump, one end of which is connected to the water outlet pipe and the other end of which is connected to the water spraying device. The water pump is used to recirculate the tailwater in the tailwater collection area back into the shell for further denitrification treatment.

[0014] The technical solution provided by this invention has the following beneficial effects:

[0015] (1) The gas-liquid two-phase biological denitrification device of the present invention has multiple packing grids installed above the biological nitrification tank, each filled with biological packing material, which enables effective utilization of the space above the biological nitrification tank. Wastewater is sprayed onto the biological packing material on the packing grids via a spray device, allowing the wastewater to fully contact the biological packing material. The biological packing material performs the first denitrification treatment on the wastewater. After denitrification by the biological packing material on the multiple packing grids, the wastewater enters the biological nitrification tank, where the biological packing material performs a second denitrification treatment. Therefore, the gas-liquid two-phase biological denitrification device of the present invention can perform multiple denitrification treatments on wastewater within a limited space, thereby improving the denitrification efficiency and treatment depth of the wastewater. Furthermore, by utilizing the space above the biological nitrification tank, the present invention improves the denitrification efficiency of wastewater per unit area, achieving effective denitrification treatment of wastewater within a relatively small space.

[0016] (2) The gas-liquid two-phase biological denitrification device of the present invention is equipped with a water spraying device, which can slowly spray the effluent into the biological packing material in the form of raindrops. This ensures that the effluent is effectively dispersed within the biological packing material as it passes through, allowing for sufficient contact between the effluent and the biological packing material, thereby increasing the contact area between the effluent and the biological packing material and thus improving the denitrification efficiency of the biological packing material for the effluent. Furthermore, in the present invention, the packing grid is alternately installed along the Y-axis on the left or right side wall of the shell. This installation method can extend the path of the effluent through the biological packing material and the time the effluent remains within the biological packing material on the packing grid within a limited space. The synergistic effect of both further improves the denitrification efficiency of the effluent.

[0017] (3) The gas-liquid two-phase biological denitrification device of the present invention is equipped with a filtration device, which can filter the tailwater after denitrification treatment by the packing grid and biological nitrification tank, thereby effectively removing pollutants from the tailwater and achieving a more efficient water purification effect. Attached Figure Description

[0018] Figure 1 A perspective view of the gas-liquid two-phase biological denitrification device provided by the present invention.

[0019] Figure 2 This is a top view of the gas-liquid two-phase biological denitrification device provided by the present invention.

[0020] Figure 3 For the present invention Figure 2 Sectional view along the middle AA.

[0021] Figure 4 This is a schematic diagram of the internal structure of the gas-liquid two-phase biological denitrification device provided by the present invention.

[0022] The following are marked in the diagram: 11, shell; 111, cavity; 112, outlet pipe; 121, spray pipe; 13, packing grid; 131, gap; 14, biological nitrification tank; 141, filter screen; 142, nitrification zone; 143, effluent collection zone; 21, collection pipe; 22, collection tank. Detailed Implementation

[0023] The present invention will now be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0024] In the description of this invention, it should be noted that directional terms such as "center," "lateral," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific scope of protection of this invention. The terms "first," "second," etc., in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "comprising" and "having," and any variations thereof, in the specification and claims of this invention, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0025] This embodiment provides a gas-liquid two-phase biological denitrification device for denitrifying the wastewater in a recirculating aquaculture system. Please refer to [reference needed]. Figure 1 , Figure 2 and Figure 3The gas-liquid two-phase biological denitrification device includes a shell 11, a water spray device, and multiple packing grids 13. The shell 11 may be a rectangular structure, and the shell 11 has a cavity 111, in which the water spray device and the packing grids 13 are installed. The length direction of the shell 11 is defined as the X-axis, the height direction as the Y-axis, and the width direction as the Z-axis. The water spray device is installed along the X-axis in the cavity 111, and the multiple packing grids 13 are located below the water spray device along the Y-axis. One end of each packing grid 13 is installed on one side wall of the shell 11, and a gap 131 is provided between the other end of each packing grid 13 and the corresponding side wall of the shell 11. Each packing grid 13 has multiple through holes, and the upper surface of each packing grid 13 and the gaps 131 are filled with biological packing material. The biological packing material is used to denitrify the effluent, and the effluent after denitrification by the biological packing material of the previous packing grid 13 flows through the gaps 131 or through holes to the next packing grid 13. By setting gap 131, the wastewater to be treated can flow along the X-axis from the upper packing grid 13 to the lower packing grid 13. By setting through holes, the wastewater to be treated can flow along the Y-axis from the through holes of the upper packing grid 13 to the lower packing grid 13. Therefore, in this embodiment, setting gap 131 and through holes not only increases the number of flow paths of wastewater in the biological packing material but also prolongs the residence time of wastewater in the biological packing material, allowing for sufficient contact between the wastewater to be treated and the biological packing material. Sufficient contact enhances the degradation and removal rate of pollutants in the wastewater by the biological packing material, achieving a more efficient purification effect on the wastewater.

[0026] Please refer to Figure 3 The shell 11 is divided into a left side wall and a right side wall along the X-axis. Two adjacent packing grids 13 are alternately fixed to the left side wall and the right side wall of the shell 11. That is, in the Y-axis direction, one packing grid 13 is fixed to the left side wall of the shell 11, and the next packing grid 13 is fixed to the right side wall of the shell 11. The alternating arrangement can prolong the contact time between the effluent and the biological packing material filled on the packing grids 13, thereby improving the denitrification efficiency of the biological packing material for the effluent.

[0027] Please refer to Figure 3 The lowest packing screen 13 located along the Y-axis and the shell 11 form a biological nitrification tank 14. The effluent to be treated, sprayed by the water spraying device, passes sequentially through each packing screen 13 for denitrification before entering the biological nitrification tank 14. The biological nitrification tank 14 is used to further denitrify the effluent after denitrification by the packing screens 13. Biological packing materials, such as K3 packing, K5 packing, or biological ceramic granules, can also be placed inside the biological nitrification tank 14, enabling it to perform secondary denitrification of the effluent and further improving the denitrification effect.

[0028] In this embodiment, multiple packing grids 13 are installed above the biological nitrification tank 14, and each packing grid 13 is filled with biological packing material. This arrangement makes full use of the space above the biological nitrification tank 14, improving the nitrification efficiency per unit area and increasing the biological nitrogen removal efficiency by about 40%-50%.

[0029] Furthermore, in this embodiment, a water flow buffer plate can be provided on the lowest packing grid 13 in the Y-axis direction. One end of the water flow buffer plate is detachably connected to the end face of the lowest packing grid 13 in the Y-axis direction near the gap 131, and the other end of the water flow buffer plate is connected to the lower end face of the previous packing grid 13. The water flow buffer plate is provided with multiple water outlet holes, the diameter of which is smaller than the particle size of the biological packing. By setting the water flow buffer plate, the biological packing filled on the last packing grid 13 can be blocked, so that the biological packing is located on the packing grid 13. At the same time, with the water outlet holes, the effluent after passing through multiple packing grids 13 can flow into the biological nitrification tank 14 through the water outlet holes or the through holes on the lowest packing grid 13.

[0030] The width of the water flow buffer plate can be one-half to two-thirds of the width of the packing grid. The water flow buffer plate can be installed at an angle of 20°-30°. By installing the water flow buffer plate, the water flow velocity can be reduced and the effluent can be guided evenly into the nitrification tank.

[0031] In this embodiment, the housing may also be provided with multiple ventilation holes (not shown in the figure), which are arranged along the X-axis and are all located above the water spray device in the Y-axis direction. The ventilation holes ensure air circulation.

[0032] It is understood that the gas-liquid two-phase biological denitrification device may also include a blower connected to the cavity 111. The blower is used to blow air along the Y-axis from the lowermost packing grid 13 to the uppermost packing grid 13. Since the flow directions of the effluent and air are opposite, free carbon dioxide in the effluent is removed by blower degassing. Furthermore, because carbon dioxide is removed from the effluent, and the air and effluent flow directions are opposite, some oxygen in the air can dissolve in the effluent, thereby increasing the dissolved oxygen content and achieving oxygenation of the effluent while removing carbon dioxide. The removed carbon dioxide, being denser than air, will rise and be discharged through the ventilation holes. Therefore, the gas-liquid two-phase biological denitrification device of this embodiment can effectively remove carbon dioxide from the effluent, reduce the acidity of the effluent, increase the dissolved oxygen content of the treated effluent, improve aquaculture water quality, and increase aquaculture efficiency.

[0033] It is understood that in this embodiment, the packing grid 13 can be fixed to the side wall of the housing 11 by bolts, or it can be slidably installed in the housing 11 by the cooperation of a slider and a groove. In this embodiment, the two sides of the packing grid 13 in the Z-axis direction are also in contact with the side wall of the housing 11 in the Z-axis direction, so that the housing 11 and the packing grid 13 can jointly form a packing cavity, which can be used to fill biological packing material.

[0034] The packing screen 13 has an angle α with the X-axis, with the angle α ranging from 0° to 30°. This angle range allows the packing screen 13 to be installed horizontally or at an angle along the X-axis. Therefore, in actual operation, the actual installation position of the packing screen 13 can be selected according to actual needs. In this embodiment, by setting the maximum angle to 30°, sufficient contact between the effluent and the biological packing material on the packing screen 13 can be achieved, while also accelerating the flow velocity of the effluent on the packing screen 13, thereby further improving the denitrification treatment speed and efficiency of the effluent.

[0035] In this embodiment, please refer to Figure 3 The spacing between two adjacent packing grids 13 in the Y-axis direction is equal. It is understood that in this embodiment, the spacing between two adjacent packing grids 13 in the Y-axis direction can satisfy the following two conditions: with a fixed amount of biological packing material, the spacing needs to ensure that the effluent can fully contact the packing material on each packing grid 13 while preventing excessive accumulation of effluent on the packing grid 13. That is, while ensuring sufficient contact between the effluent and the packing material, the flow time of the effluent on the packing grid 13 can also be considered, resulting in an optimal choice through the synergy of both factors. This improves the efficiency of the biological packing material in denitrifying the effluent and appropriately accelerates the flow time of the effluent within the packing grid 13, thereby increasing the speed of effluent denitrification.

[0036] The length of the gap 131 in the X-axis direction is one-tenth to one-fifteenth of the length of the packing grid 13 in the X-axis direction.

[0037] The spacing between two adjacent packing grids in the Y-axis direction can be 150mm-200mm, and the thickness of each packing grid layer can be 30mm-50mm. The pore size of the packing grid can be 5mm-10mm, and the porosity per square meter of packing grid can be 50%-70%. The packing grids are arranged in a staggered manner, with the offset angle between adjacent layers being 30°-45° to extend the flow path of the tailwater and enhance the denitrification effect. The tailwater is sprayed by a water spraying device to form uniformly distributed droplets with a droplet diameter of 1mm-3mm. The spraying angle of the water spraying device can be 90°-120° to ensure that the tailwater covers 80%-95% of the surface area of ​​each packing grid layer.

[0038] The water spraying device includes a spray pipe 121 and multiple nozzles. The spray pipe 121 can be a hollow cuboid structure. One end of each nozzle is connected to the spray pipe 121, and the other end of each nozzle is aligned with the packing grid 13. In this embodiment, the flow velocity of the nozzles is very low, making the wastewater flowing out of the nozzles similar to raindrops falling onto the biological packing. By converting the wastewater into raindrops through the water spraying device in this embodiment, the converted raindrops can fall into the biological packing on the packing grid 13 below, ensuring that the wastewater can be effectively dispersed within the biological packing as it passes through, thereby increasing the contact area between the wastewater and the biological packing, allowing the wastewater to fully contact the biological packing, and thus improving the efficiency of denitrification treatment of the wastewater.

[0039] Understandably, the nozzles can also be directly replaced with spray holes. That is, multiple spray holes are provided at the end of the spray pipe 121 facing the packing grid 13, and the tailwater can flow into the biological packing through these spray holes.

[0040] The length of the packing grid 13 in the Z-axis direction can be much greater than the length of the spray pipe 121 in the Z-axis direction, so that all the water droplets sprayed from the nozzles on the spray pipe 121 can fall into the biological packing material on the packing grid 13, thereby allowing the water droplets to fully contact the biological packing material and thus improving the denitrification efficiency of the effluent.

[0041] In this embodiment, anaerobic bacteria grow inside the biological packing material, producing denitrification to remove nitrogen, while aerobic bacteria grow on the outside of the biological packing material to remove organic matter from the effluent. The process of treating effluent using biological packing material involves both nitrification and denitrification simultaneously, thereby significantly improving the nitrogen removal efficiency. It is understood that the biological packing material can be one of K3 packing material, K5 packing material, or biological ceramic granule packing material. In this embodiment, biological ceramic granule packing material is preferred as the main packing material, and in this embodiment, the biological packing material is filled onto the packing grid 13. The effluent is sprayed onto the packing grid 13 via a spraying device. This spraying method creates a micro-spray environment for the effluent to be treated, allowing the effluent to fully contact the biological packing material, thereby improving the nitrogen removal efficiency of the biological packing material.

[0042] In this embodiment, the bio-ceramic filler is filled on the packing grid 13, and in this environment, the bio-ceramic filler can fully contact the air, thus effectively avoiding the problem of bio-ceramic filler settling on water droplets and forming an anaerobic reaction. Furthermore, the price of the bio-ceramic filler is approximately half that of the traditional K3 filler, but its denitrification effect is comparable to that of the K3 filler. Therefore, using bio-ceramic filler in this embodiment can also reduce the denitrification cost of the entire gas-liquid two-phase denitrification device.

[0043] Please refer to Figure 3 and Figure 4The biological nitrification tank 14 is equipped with a filtration device. The filtration device divides the biological nitrification tank 14 into a nitrification zone 142 and a effluent collection zone 143. The nitrification zone 142 contains biological packing material and is used for secondary denitrification of the effluent after it has passed through multiple packing screens 13. The filtration device filters the effluent after secondary denitrification in the nitrification zone 142, and the filtered effluent enters the effluent collection zone 143. By installing the filtration device, the effluent after secondary denitrification can be filtered within the biological nitrification tank 14, thereby improving the cleanliness of the treated effluent.

[0044] The filtration device can be composed of multiple filter screens 141, which are installed sequentially in the biological nitrification tank 14 along the X-axis. The pore size of the filter screens 141 gradually decreases from the nitrification zone 142 to the effluent collection zone 143, so that the filtration device can perform step-by-step filtration of the effluent entering the effluent collection zone 143 from the nitrification zone 142, thereby further reducing the amount of impurities in the filtered effluent and improving the cleanliness of the filtered effluent.

[0045] Please refer to Figure 3 and Figure 4 The filter screen 141 can be an inverted L-shaped structure. One end of the filter screen 141 is connected to the left side wall of the shell 11, and the other end is connected to the lower side wall of the shell 11. The front end face of the filter screen 141 is connected to the front side wall of the shell 11, and the rear end face of the filter screen 141 is connected to the rear side wall of the shell 11, so that the entire filter screen 141 can isolate the biological nitrification tank 14, dividing the biological nitrification tank 14 into a nitrification zone 142 and a effluent collection zone 143. The nitrification zone 142 and the effluent collection zone 143 can only be connected through the mesh of the filter screen 141.

[0046] A water outlet pipe 112 may also be installed on the housing 11, please refer to Figure 3 The outlet pipe 112 connects to the tailwater collection area 143. The tailwater in the tailwater collection area 143, after two denitrification treatments and excess, can be circulated through the outlet pipe 112 to the recirculating aquaculture system for reuse.

[0047] The gas-liquid two-phase biological denitrification device also includes a water pump, with one end connected to a blowpipe and the other end connected to a spray device. During the denitrification treatment of the effluent, the nitrogen content in the effluent collection area 143 can be periodically monitored. If the nitrogen content in the effluent is still higher than the set value for nitrogen content in the aquaculture water of the recirculating aquaculture system, the water pump can be activated. The pump can recirculate the effluent in the collection area 143 back into the shell 11 for further denitrification. In actual treatment, this cycle can be repeated multiple times until the nitrogen content in the effluent collection area 143 reaches the nitrogen content requirement for the aquaculture water in the recirculating aquaculture system.

[0048] The basic principles, main features, and advantages of this invention have been described above. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection claimed by this invention is defined by the appended claims and their equivalents.

Claims

1. A gas-liquid two-phase biological denitrification device, characterized in that, It includes: The enclosure (11) includes a housing (11), a water spraying device, and multiple packing grids (13). The housing (11) has a cavity (111). The length direction of the housing (11) is defined as the X-axis, the height direction as the Y-axis, and the width direction as the Z-axis. The water spraying device is installed in the cavity (111) along the X-axis and is located above the multiple packing grids (13). The water spraying device is used to spray the wastewater to be treated onto the packing grids (13). The multiple packing grids (13) are installed at intervals along the Y-axis in the cavity (111). One end of the packing grid (13) is installed on one side wall of the housing (11), and a gap (131) is provided between the other end of each packing grid (13) and the opposite side wall of the housing (11); the spacing between any two adjacent packing grids (13) in the Y-axis direction is equal, and the length of the gap (131) in the X-axis direction is one-tenth to one-fifteenth of the length of the packing grid (13) in the X-axis direction; the packing grid (13) is provided with an angle α with the X-axis direction, and the range of the angle α is 0°≤α≤30°; Each of the packing grids (13) has multiple through holes, and the upper end face of each packing grid (13) and the gap (131) are filled with biological packing material. The biological packing material is used to denitrify the effluent, and the effluent after denitrification by the biological packing material on the previous packing grid (13) flows to the next packing grid (13) through the gap (131) or the through holes. The shell (11) is divided into a left side wall and a right side wall on two side walls along the X-axis direction. Two adjacent packing grids (13) are alternately fixed to the left side wall and the right side wall of the shell (11). The packing grid (13) located at the lowest point in the Y-axis direction and the shell (11) form a biological nitrification tank (14). The wastewater to be treated sprayed by the water spraying device passes through each of the packing grids (13) in sequence for denitrification treatment and then enters the biological nitrification tank (14). The biological nitrification tank (14) is used to perform a second denitrification treatment on the wastewater after it has been denitrified by the packing grids (13).

2. The gas-liquid two-phase biological denitrification device as described in claim 1, characterized in that, The biological nitrification tank (14) is equipped with a filtration device, which divides the biological nitrification tank (14) into a nitrification zone (142) and a tailwater collection zone (143). The nitrification zone (142) is used to perform secondary denitrification on the tailwater after it has been denitrified by multiple packing grids (13). The filtration device is used to filter the tailwater after secondary denitrification in the nitrification zone (142), and the filtered tailwater enters the tailwater collection zone (143).

3. The gas-liquid two-phase biological denitrification device as described in claim 2, characterized in that, The filtration device consists of multiple filter screens (141), which are installed sequentially in the biological nitrification tank (14) along the X-axis. The pore size of the filter screens (141) gradually decreases from the nitrification zone (142) to the effluent collection zone (143).

4. The gas-liquid two-phase biological denitrification device as described in claim 1, characterized in that, The water spraying device includes a spray pipe (121) and a plurality of nozzles, the plurality of nozzles being connected to the spray pipe (121) respectively, and the plurality of nozzles being directed toward the packing grid (13) located below the spray pipe (121).

5. The gas-liquid two-phase biological denitrification device as described in claim 1, characterized in that, The biological packing material is a biological ceramic granule packing material.

6. The gas-liquid two-phase biological denitrification device as described in claim 2, characterized in that, The housing (11) is also equipped with a water outlet pipe (112), which is connected to the tailwater collection area (143).

7. The gas-liquid two-phase biological denitrification device as described in claim 6, characterized in that, The gas-liquid two-phase biological denitrification device also includes a water pump, one end of which is connected to the outlet pipe (112), and the other end of which is connected to the water spraying device. The water pump is used to recirculate the tailwater in the tailwater collection area (143) back into the shell (11) for further denitrification treatment.

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