Expanded granular sludge bed system and method for treating sewage using hydroxylamine oxidation

Abstract

This invention discloses an expanded granular sludge bed system and a method for treating wastewater by hydroxylamine oxidation. The system includes a reactor body, a membrane module connected to the reactor body, a water collection tank, a first storage bottle, a second storage bottle, and a gas storage bottle connected to the membrane module. The reactor body includes a shell, a water distributor and a three-phase separator located at the bottom of the shell. The membrane module includes an outer cylinder, a sealing plate located at the lower end of the inner cylinder, a support connected to the sealing plate, and a filter membrane located on the support. Using the system of this invention for hydroxylamine oxidation treatment of wastewater is simple to operate, less prone to equipment corrosion, helps to save resources and energy, and can oxidize hydroxylamine without supplying methane, which has profound significance for practical applications.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an expanded granular sludge bed system and a method for treating wastewater by hydroxylamine oxidation. Background Technology

[0002] In recent years, my country has made remarkable achievements in agriculture, medicine, and semiconductors. However, this has also led to the release of large amounts of hydroxylamine into the natural environment from the widely used hydroxylamine hydrochloride and hydroxylamine sulfate in these fields. Hydroxylamine is a nitrogen-containing inorganic compound that is often released into water bodies as a denitrification byproduct of ammonia-oxidizing bacteria, ammonia-oxidizing archaea, and fully nitrifying bacteria. The presence of hydroxylamine can damage the nucleic acid components of bacteria, leading to DNA damage and inhibiting microbial growth. Studies have shown that hydroxylamine in wastewater can cause biological mutations, and free hydroxylamine can significantly inhibit the nitrification and denitrification capabilities of bacteria. Furthermore, hydroxylamine is unstable; when external environmental conditions change, it decomposes rapidly and releases heat, potentially causing safety accidents. Traditional hydroxylamine removal methods release large amounts of acid that corrode equipment and consume significant amounts of energy and resources.

[0003] It has been reported that hydroxylamine can be oxidized to nitric oxide by hydroxylamine oxidase, and large-scale emissions of nitric oxide will lead to increased greenhouse gas levels and exacerbate global warming. Recent studies have found that, nitric oxide can be directly reduced to nitrogen and oxygen under the catalysis of nitric oxide superoxide oxidase, mediated by microorganisms. The discovery of nitric oxide superoxide oxidase opens up new possibilities for treating hydroxylamine oxidation in wastewater and reducing greenhouse gas emissions, but no microorganisms capable of carrying out this process have yet been discovered.

[0004] Nitrite-dependent anaerobic methane oxidation (n-DAMO) is a newly discovered nitrogen cycle process mediated by a type of NC10 bacterium. Studies have shown that n-DAMO bacteria possess genes for hydroxylamine oxidoreductase-like proteins, suggesting that n-DAMO bacteria may oxidize hydroxylamine to nitric oxide via hydroxylamine oxidoreductase, and then directly oxidize the resulting nitric oxide to nitrogen gas under the action of nitric oxide superoxide dismutase. However, since n-DAMO bacteria can only utilize intracellular oxygen produced by nitrite reduction, this hydroxylamine oxidation process will depend on nitrite. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an expanded granular sludge bed system and a method for treating wastewater via hydroxylamine oxidation.

[0006] The technical solution of the present invention is: an expanded granular sludge bed system, comprising a reactor body, a membrane module connected to the reactor body, a water collection tank, a first liquid storage bottle, a second liquid storage bottle, and a gas storage bottle connected to the membrane module;

[0007] The reactor body includes a shell, a water distributor located at the bottom of the shell, and a three-phase separator located at the top of the shell. The water distributor is connected to a second storage bottle via a first inlet pipe, and a second inlet pump is installed at the connection point. The three-phase separator is connected to a water collection tank via a first outlet pipe and to a membrane module via a second outlet pipe. The first storage bottle is connected to the interior of the shell via a third inlet pipe, and a first inlet pump is installed on the third inlet pipe.

[0008] The membrane module includes an outer cylinder, a sealing plate disposed at the lower end of the inner cavity of the outer cylinder, a support disposed inside the outer cylinder and connected to the sealing plate, and a filter membrane sleeved on the support; the outer cylinder is connected to a second water inlet pipe and a second water outlet pipe through a second water inlet pipe, connected to a first water outlet pipe through a third water outlet pipe, and connected to a gas storage cylinder through a first air inlet pipe; a circulation pump is provided at the connection between the third water outlet pipe and the first water outlet pipe, and a pressure valve is provided at the connection between the gas storage cylinder and the first air inlet pipe and the second air inlet pipe.

[0009] Furthermore, the water distributor includes two interlocking and interconnected annular pipes and several water distribution branch pipes equidistantly distributed on the underside of the two annular pipes; the first inlet pipe is connected to the annular pipe located on the inner side.

[0010] Note: By placing the water distribution branch pipe on the bottom surface of the annular pipe, it is beneficial to reduce the impact of water flow on the expanded granular sludge inside the shell, and also to improve the uniformity of water distribution inside the shell.

[0011] Furthermore, the three-phase separator includes a folded plate component connected to the inner wall of the shell, a settling chute disposed at the upper end of the folded plate component, and a water outlet trough disposed at the upper end of the settling chute; the folded plate component is composed of a series of inclined plates arranged in pairs; the settling chute is perpendicular to the inclined plates, and a material drop trough is disposed at the bottom of the settling chute between two adjacent sets of inclined plates; several sedimentation plates are evenly distributed inside the water outlet trough; the first water outlet pipe and the second water outlet pipe are respectively connected to the two ends of the water outlet trough;

[0012] Explanation: When wastewater carrying nitrogen gas and sludge particles passes through the inclined plate, it impacts the side wall of the inclined plate. The sludge particles in the wastewater enter the settling trough and then enter the shell through the discharge chute, achieving the separation of methane gas and wastewater. When the wastewater level is higher than the effluent trough, the wastewater enters the effluent trough. The fine sludge impurities carried in the wastewater are trapped inside the effluent trough by the action of the settling plate. The purified wastewater is discharged through the first and second effluent pipes, which helps to improve the separation effect of methane gas and sludge particles in the wastewater and avoids the loss of activated sludge inside the shell.

[0013] Furthermore, a buffer assembly is provided inside the housing, which includes a rotating sleeve rotatably engaged inside the housing and a buffer disk located at the bottom end of the rotating sleeve; a conical gear ring is provided at the upper end of the side wall of the rotating sleeve; a return spring is provided on the inner wall of the housing to abut against the side wall of the rotating sleeve; several inclined actuating plates are equidistantly distributed on the bottom surface of the buffer disk, with adjacent actuating plates having opposite inclination directions; a drive motor is provided on the side wall of the housing, the output shaft of the drive motor passes through the housing, and an incomplete bevel gear is provided on the output shaft to mesh with the conical gear ring;

[0014] Explanation: The drive motor rotates the incomplete bevel gear, which in turn causes the rotating sleeve and buffer disc to rotate under the action of the bevel gear ring and the incomplete bevel gear. Due to the setting of the return spring, the rotating sleeve and buffer disc reciprocate inside the housing. The agitator plate set on the bottom surface of the buffer disc continuously agitates the rising water flow inside the housing, which helps to reduce the water flow velocity, thereby reducing the impact of the water flow on the three-phase separator and improving the separation effect.

[0015] Furthermore, the sealing plate is slidably engaged with the outer cylinder and rotatably engaged with the end cap. A damping spring is provided on the inner wall of the outer cylinder to abut against the bottom surface of the sealing plate. Several rotating rods are evenly distributed around the two end caps. A spiral groove is provided on the inner wall of the outer cylinder to slidably engage with each rotating rod. An impact blade is provided on the end cap located at the top of the support rod.

[0016] Explanation: When water enters the outer cylinder and impacts the impeller, the impeller can drive the support and filter membrane to move downward along the inner wall of the outer cylinder. Due to the setting of the rotating rod and the spiral groove, the support rotates during the downward movement, so that the membrane fibers on the filter membrane always remain floating. This is beneficial to improve the contact efficiency between sewage and membrane fibers, thereby improving the filtration effect of the filter membrane on sewage.

[0017] The present invention also provides a method for treating wastewater by hydroxylamine oxidation, based on the above-mentioned expanded granular sludge bed system, comprising the following steps:

[0018] S1. Add flocculent sludge containing denitrifying anaerobic methanogenic bacteria and anaerobic granular sludge into the shell; fill the first storage bottle with wastewater containing nitrite and the second storage bottle with wastewater containing hydroxylamine; fill the gas storage bottle with a mixture of 95% methane and 5% carbon dioxide; control the internal temperature of the shell to 31-33℃ and the pH to 7.0-7.5.

[0019] S2. Turn on the first and second inlet pumps respectively, so that the wastewater containing nitrite in the first storage bottle enters the shell through the third inlet pipe, and the wastewater containing hydroxylamine in the second storage bottle enters the shell through the first inlet pipe; control the concentration of nitrite inside the shell to 1-20 mg / L. -1 ;

[0020] S3. Wastewater containing nitrite is diffused into the shell through a distributor and comes into contact with flocculent sludge and anaerobic granular sludge containing denitrifying anaerobic methanogenic bacteria. Hydroxylamine in the wastewater is oxidized by the flocculent sludge and anaerobic granular sludge containing denitrifying anaerobic methanogenic bacteria, producing nitrogen gas. The wastewater carrying nitrogen gas and sludge particles passes through a three-phase separator, where the nitrogen gas and sludge particles are separated. A portion of the wastewater enters a collection tank through the first effluent pipe, while the other portion enters the filter membrane through the second effluent pipe. The concentration of hydroxylamine in the effluent from both the first and second effluent pipes is controlled to be less than 0.2 mg N / L. -1 ; and the wastewater containing hydroxylamine was treated at 4–28 mg NL -1 d -1 The loading rate is introduced into the casing slowly and continuously;

[0021] S4. A mixture of 95% methane and 5% carbon dioxide from the gas storage cylinder is introduced into the filter membrane through the first and second inlet pipes, respectively. The pressure inside the filter membrane is adjusted to 80 kPa by the pressure valve to accelerate the dissolution rate of methane in the wastewater. The wastewater containing dissolved methane is discharged through the third outlet pipe and enters the shell through the first inlet pipe under the action of the circulation pump.

[0022] S5. Repeat steps S3 and S4 until the water from the third outlet pipe meets the discharge requirements.

[0023] Compared with the prior art, the beneficial effects of the present invention are reflected in the following aspects:

[0024] First, the system of the present invention, mediated by n-DAMO bacteria, can directly oxidize nitric oxide produced by hydroxylamine oxidation into nitrogen and oxygen, reducing greenhouse gas emissions while solving the problems of easy equipment corrosion, cumbersome operation and high energy consumption in traditional hydroxylamine oxidation methods. It provides a simple, energy-saving and promising alternative for hydroxylamine oxidation in wastewater treatment.

[0025] Secondly, the system of the present invention utilizes anaerobic methane-oxidizing bacteria enriched and cultured and inoculated in an expanded sludge bed reactor to directly oxidize nitric oxide produced by hydroxylamine oxidation into nitrogen gas, thereby alleviating the global warming problem caused by greenhouse gas emissions.

[0026] Third, in the system of the present invention, the water distributor improves the uniformity of water intake inside the reactor body, thereby ensuring sufficient contact between the sewage and the flocculent sludge and anaerobic granular sludge containing denitrifying anaerobic methanogenic bacteria, and improving the oxidation effect of hydroxylamine in the sewage; the three-phase separator effectively reduces the loss of activated sludge, so that the reactor body always maintains high-efficiency operation.

[0027] Fourth, during operation, the membrane module of the present invention can not only be automatically cleaned, extending the service life of the membrane module; at the same time, since the filter membrane is always rotating inside the outer cylinder, it is beneficial to improve the contact efficiency between the sewage and the membrane fibers on the filter membrane, thereby improving the filtration effect of the sewage. Attached Figure Description

[0028] Figure 1 This is a longitudinal sectional view of the system of the present invention;

[0029] Figure 2 This is a longitudinal sectional view of the reactor body of the present invention;

[0030] Figure 3 This is a diagram showing the distribution of the water distribution branch pipes on the annular pipe according to the present invention;

[0031] Figure 4 This is a schematic diagram of the connection between the annular tube and the shell of the invention;

[0032] Figure 5 This is the present invention. Figure 4 A magnified view of a portion of point A in the middle;

[0033] Figure 6 This is a schematic diagram showing the connection between the folded plate component of the present invention and the settling chute and the outlet chute;

[0034] Figure 7 This is a schematic diagram showing the connection between the three-phase separator and the housing of the present invention;

[0035] Figure 8 This is a longitudinal sectional view of the membrane module of the present invention;

[0036] Figure 9 This is a schematic diagram of the connection between the end cap and the outer cylinder of the present invention;

[0037] Figure 10 This is a schematic diagram showing the connection between the buffer assembly and the housing of the present invention;

[0038] Figure 11 This is a diagram showing the distribution of the actuating plate on the buffer disk according to the present invention;

[0039] Among them, 1-reactor body, 10-shell, 100-first inlet pipe, 101-first outlet pipe, 102-second outlet pipe, 103-third inlet pipe, 11-water distributor, 110-ring pipe, 111-water distribution branch pipe, 1110-first outlet trough, 112-floating pipe, 1120-second outlet trough, 113-compression spring, 12-three-phase separator, 120-folding plate component, 1200-inclined plate, 121-sedimentation trough, 1210-feeding trough, 122-outlet trough, 1222-sedimentation plate, 2-membrane module, 20-outer cylinder, 200-second inlet pipe, 201-third outlet pipe, 20 2-First air inlet pipe, 203-Second air inlet pipe, 204-Damping spring, 205-Helical groove, 21-Sealing plate, 22-Bracket, 220-End cap, 221-Support rod, 222-Rotating rod, 23-Filter membrane, 24-Circulation pump, 25-Impact blade, 26-Cleaning brush plate, 3-Water collection tank, 4-First liquid storage bottle, 40-First water inlet pump, 5-Second liquid storage bottle, 50-Second water inlet pump, 6-Air storage bottle, 60-Pressure valve, 7-Buffer assembly, 70-Rotating sleeve, 700-Reset spring, 71-Buffer disc, 710-Actuating plate, 72-Conical gear ring, 73-Drive motor, 730-Incomplete bevel gear. Detailed Implementation

[0040] Example 1

[0041] like Figure 1 The expanded granular sludge bed reaction system includes a reactor body 1, a membrane module 2 connected to the reactor body 1, a water collection tank 3, a first liquid storage bottle 4, a second liquid storage bottle 5, and a gas storage bottle 6 connected to the membrane module 2.

[0042] like Figure 1 , 2 As shown, the reactor body 1 includes a shell 10, a water distributor 11 disposed at the bottom of the shell 10, and a three-phase separator 12 disposed at the top of the shell 10. The water distributor 11 is connected to the second storage bottle 5 through a first inlet pipe 100, and a second inlet pump 50 is provided at the connection. The three-phase separator 12 is connected to the water collection tank 3 through a first outlet pipe 101 and to the membrane module 2 through a second outlet pipe 102. The first storage bottle 4 is connected to the inside of the shell 10 through a third inlet pipe 103. A first inlet pump 40 is provided on the third inlet pipe 103.

[0043] like Figure 1 , 8As shown, the membrane module 2 includes an outer cylinder 20, a sealing plate 21 disposed at the lower end of the inner cavity of the outer cylinder 20, a support 22 disposed inside the outer cylinder 20 and connected to the sealing plate 21, and a filter membrane 23 sleeved on the support 22; the outer cylinder 20 is connected to the second water outlet pipe 102 through the second water inlet pipe 200, connected to the first water outlet pipe 101 through the third water outlet pipe 201, and connected to the gas storage cylinder 6 through the first air inlet pipe 203; a circulation pump 24 is provided at the connection between the third water outlet pipe 201 and the first water outlet pipe 101, and a pressure valve 60 is provided at the connection between the gas storage cylinder 6 and the first air inlet pipe 202 and the second air inlet pipe 203; the support 22 includes two end caps 220 and several support rods 221 equidistantly distributed between the two end caps 220; the filter membrane 23 is sleeved on the outside of each support rod 221; the third water outlet pipe 201 passes through the end cap 220 at the bottom end of the support rod 221.

[0044] Example 2

[0045] This embodiment describes a method for treating wastewater by hydroxylamine oxidation, based on an expanded granular sludge bed system of Embodiment 1, including the following steps:

[0046] S1. Flocculent sludge containing denitrifying anaerobic methanogenic bacteria and anaerobic granular sludge are added into the shell 10; wastewater containing nitrite is filled into the first storage bottle 4, and wastewater containing hydroxylamine is filled into the second storage bottle 5; a mixture of 95% methane and 5% carbon dioxide is filled into the gas storage bottle 6; the internal temperature of the shell 10 is controlled at 31°C and the pH is 7.0.

[0047] S2. Turn on the first inlet pump 40 and the second inlet pump 50 respectively, so that the wastewater containing nitrite in the first storage bottle 4 enters the shell 10 through the third inlet pipe 103, and the wastewater containing hydroxylamine in the second storage bottle 5 enters the shell 10 through the first inlet pipe 100; control the concentration of nitrite inside the shell 10 to 1 mg NL. -1 ;

[0048] S3. Wastewater containing nitrite diffuses into the shell 10 through the distributor 11, and comes into contact with flocculent sludge and anaerobic granular sludge containing denitrifying anaerobic methanogenic bacteria. Hydroxylamine in the wastewater is oxidized by the flocculent sludge and anaerobic granular sludge containing denitrifying anaerobic methanogenic bacteria, producing nitrogen gas. The wastewater carrying nitrogen gas and sludge particles passes through the three-phase separator 12, where the nitrogen gas and sludge particles are separated. A portion of the wastewater enters the collection tank 3 through the first effluent pipe 101, and the other portion enters the filter membrane 23 through the second effluent pipe 200. The concentration of hydroxylamine in the effluent from the first effluent pipe 101 and the second effluent pipe 102 is controlled to be less than 0.2 mg / L. -1 ; and the wastewater containing hydroxylamine was treated with 4 mg NL -1 d -1The loading rate is slowly and continuously introduced into the housing 10;

[0049] S4. The mixture of 95% methane and 5% carbon dioxide in the gas storage cylinder 6 is introduced into the filter membrane 23 through the first inlet pipe 202 and the second inlet pipe 203, respectively. The pressure inside the filter membrane 23 is adjusted to 80 kPa by the pressure valve 60, thereby accelerating the dissolution rate of methane in the wastewater. The wastewater containing dissolved methane is discharged through the third outlet pipe 201 and enters the shell 10 through the first inlet pipe 100 under the action of the circulation pump 24.

[0050] S5. Repeat steps S3 and S4 until the water effluent from the third outlet pipe 201 meets the discharge requirements.

[0051] Example 3

[0052] The difference between this implementation and Example 1 is that:

[0053] like Figure 3 , 4 As shown in Figure 5, the water distributor 11 includes two annular pipes 110 that are nested together and interconnected, and several water distribution branch pipes 111 that are equidistantly distributed on the bottom surface of the two annular pipes 110; the first water inlet pipe 100 is connected to the annular pipe 110 located on the inner side; a floating pipe 112 is slidably engaged inside the water distribution branch pipe 111, and a compression spring 113 that abuts against the floating pipe 112 is provided inside the water distribution branch pipe 111; a first water outlet groove 1110 is provided on the water distribution branch pipe 111, and a second water outlet groove 1120 that can communicate with the first water outlet groove 1110 is provided on the floating pipe 112.

[0054] By placing the water distribution branch pipe 111 on the lower surface of the annular pipe 110, it is beneficial to reduce the impact of water flow on the expanded granular sludge inside the shell 10, and also to improve the uniformity of water distribution inside the shell 10. When sewage enters the water distribution branch pipe 111 at a certain pressure, the floating pipe 112 pushes the compression spring 113, and makes the second water outlet 1120 connected to the first water outlet 1110. When the system stops, the floating pipe 112 resets under the action of the compression spring 113, preventing sludge particles inside the shell 10 from clogging the water distribution branch pipe 111.

[0055] Example 4

[0056] This embodiment describes a method for treating wastewater by hydroxylamine oxidation, based on an expanded granular sludge bed system from Embodiment 3, but differing from Embodiment 2 in that:

[0057] In step S1, the internal temperature of the shell 10 is controlled at 32°C and the pH is 7.3;

[0058] In step S2, the concentration of nitrite inside the shell 10 is controlled to be 12 mg NL.-1 ;

[0059] In step S3, wastewater enters the two annular pipes 110 through the first inlet pipe 100. Under the pressure of the floating pipe 112, it moves downward along the water distribution branch pipe 111 and pushes the compression spring 113, making the second outlet tank 1120 connected to the first outlet tank 1110, thus achieving uniform water distribution inside the shell 10. The concentration of hydroxylamine in the water from the first outlet pipe 101 and the second outlet pipe 102 is controlled to be less than 0.2 mg NL. -1 ; and the wastewater containing hydroxylamine was treated with 20 mg NL -1 d -1 The loading rate is slowly and continuously introduced into the housing 10.

[0060] Example 5

[0061] The difference between this embodiment and Embodiment 3 is that:

[0062] like Figure 6 , 7 As shown, the three-phase separator 12 includes a folded plate component 120 connected to the inner wall of the housing 10, a settling chute 121 disposed at the upper end of the folded plate component 120, and a water outlet trough 122 disposed at the upper end of the settling chute 121. The folded plate component 120 is composed of a group of inclined plates 1200 arranged in pairs. The settling chute 121 is perpendicular to the inclined plates 1200. A material drop trough 1210 is provided at the bottom of the settling chute 121 between two adjacent groups of inclined plates 1200. Several sedimentation plates 1222 are evenly distributed inside the water outlet trough 122. The first water outlet pipe 101 and the second water outlet pipe 102 are respectively connected to the two ends of the water outlet trough 122.

[0063] When wastewater passes through the three-phase separator 12, the nitrogen gas and sludge particles carried in the wastewater are effectively separated, which helps to improve the separation effect of methane gas and sludge particles in wastewater, and also avoids the loss of activated sludge inside the shell 10.

[0064] Example 6

[0065] This embodiment describes a method for treating wastewater by hydroxylamine oxidation, based on an expanded granular sludge bed system from Embodiment 5, but differing from Embodiment 4 in that:

[0066] In step S1, the internal temperature of the shell 10 is controlled at 33°C and the pH is 7.5;

[0067] In step S2, the concentration of nitrite inside the shell 10 is controlled to be 20 mg NL. -1 ;

[0068] In step S3, when the wastewater carrying nitrogen and sludge particles passes through the inclined plate 1200, it impacts the side wall of the inclined plate 1200. The sludge particles in the wastewater enter the settling trough 121 and then enter the shell 10 through the discharge chute 1210, achieving the separation of methane gas and wastewater. When the wastewater level is higher than the effluent tank 122, the wastewater enters the effluent tank 122. The fine sludge impurities carried in the wastewater are trapped inside the effluent tank 122 by the sedimentation plate 1222. The purified wastewater is discharged through a first effluent pipe 101 and a second effluent pipe 102. The concentration of hydroxylamine in the effluent from the first effluent pipe 101 and the second effluent pipe 102 is controlled to be less than 0.2 mg / L. -1 ; and the wastewater containing hydroxylamine was treated with 28 mg NL -1 d -1 The loading rate is slowly and continuously introduced into the housing 10.

[0069] Example 7

[0070] The difference between this embodiment and embodiment 5 is that:

[0071] like Figure 2 As shown, the top of the shell 10 is cylindrical, the diameter of the top of the shell 10 is larger than the diameter of the middle part of the shell 10, the connection between the shell 10 and the middle part of the shell 10 is frustum-shaped, and the bottom of the shell 10 is conical;

[0072] The top diameter of the shell 10 is larger than the middle diameter of the shell 10. When the sewage enters the interior of the shell 10, the flow velocity is relatively large, which is conducive to the settling of sludge. However, when the sewage enters the top of the shell 10, the flow velocity decreases to prevent the sewage flow velocity from being too high and causing sludge to flow out from the first outlet pipe 101.

[0073] Example 8

[0074] The difference between this embodiment and embodiment 7 is that:

[0075] like Figure 2 , 10 As shown in Figure 11, a buffer assembly 7 is provided inside the housing 10. The buffer assembly 7 includes a rotating sleeve 70 that is rotatably engaged inside the housing 10 and a buffer disk 71 provided at the bottom end of the rotating sleeve 70. A conical gear ring 72 is provided at the upper end of the side wall of the rotating sleeve 70. A return spring 700 is provided on the inner wall of the housing 10 and abuts against the side wall of the rotating sleeve 70. Several inclined actuating plates 710 are equidistantly distributed on the lower bottom surface of the buffer disk 71, and the inclination directions of two adjacent actuating plates 710 are opposite. A drive motor 73 is provided on the side wall of the housing 10. The output shaft of the drive motor 73 passes through the housing 10, and an incomplete bevel gear 730 that meshes with the conical gear ring 72 is provided on the output shaft.

[0076] By setting the buffer component 7, the flow velocity of the water at the top of the shell 10 is reduced, thereby reducing the impact of the water flow on the three-phase separator 12, improving the performance of the three-phase separator 12, and also preventing the loss of activated sludge.

[0077] Example 9

[0078] This embodiment describes a method for treating wastewater by hydroxylamine oxidation, based on an expanded granular sludge bed system of Example 8, which differs from Example 6 in that:

[0079] In step 3, the drive motor 73 drives the incomplete bevel gear 730 to rotate, thereby causing the rotating sleeve 70 and the buffer disk 71 to rotate under the action of the bevel gear ring 72 and the incomplete bevel gear 730. Due to the setting of the reset spring 700, the rotating sleeve 70 and the buffer disk 71 reciprocate inside the housing 10. The agitator plate 710 set on the bottom surface of the buffer disk 71 continuously stirs the rising water flow inside the housing 10.

[0080] Example 10

[0081] The difference between this embodiment and embodiment 8 is that:

[0082] like Figure 8 , 9 As shown, the sealing plate 21 is slidably engaged with the outer cylinder 20 and rotatably engaged with the end cap 220. A damping spring 204 is provided on the inner wall of the outer cylinder 20, which abuts against the bottom surface of the sealing plate 21. Four rotating rods 222 are evenly distributed around the two end caps 220. A spiral groove 205 is provided on the inner wall of the outer cylinder 20, which is slidably engaged with each of the rotating rods 222. An impact blade 25 is provided on the end cap 220 located at the top of the support rod 221. A cleaning brush plate 26 is provided on the inner wall of the outer cylinder 20, which abuts against the filter membrane 23.

[0083] By moving the support 22 inside the outer cylinder 20, the membrane fibers on the filter membrane 23 can always remain floating, which is beneficial to improving the contact efficiency between sewage and membrane fibers, thereby improving the filtration effect of the filter membrane 23 on sewage; the cleaning brush 26 can remove impurities from the surface of the filter membrane 23, thus improving the service life of the filter membrane 23.

[0084] Example 11

[0085] This embodiment describes a method for treating wastewater by hydroxylamine oxidation, based on an expanded granular sludge bed system of Example 10, which differs from Example 9 in that:

[0086] In step S4, when water enters the outer cylinder 20 and impacts the impeller 25, the impeller drives the support 22 and the filter membrane 23 to move downward along the inner wall of the outer cylinder 20. Due to the setting of the rotating rod 222 and the spiral groove 205, the support 22 rotates during its downward movement, so that the membrane fibers on the filter membrane 23 always remain floating. When the filter membrane 23 rotates and moves with the support 22 inside the outer cylinder 20, the cleaning brush 26 can remove impurities from the surface of the filter membrane 23.

[0087] It should be noted that the filter membrane 23, circulation pump 24, first inlet pump 40, second inlet pump 50, pressure valve 60 and drive motor 73 used in this invention all adopt existing technology and are not specifically limited here. Appropriate products can be selected according to actual needs.

Claims

1. A method for treating wastewater by hydroxylamine oxidation based on an expanded granular sludge bed system, characterized in that, Includes the following steps: S1. Add flocculent sludge containing denitrifying anaerobic methanogenic bacteria and anaerobic granular sludge into the shell (10); fill the first storage bottle (4) with wastewater containing nitrite and the second storage bottle (5) with wastewater containing hydroxylamine; fill the gas storage bottle (6) with a mixture of 95% methane and 5% carbon dioxide; control the internal temperature of the shell (10) to 31-33°C and the pH to 7.0-7.

5. S2. Turn on the first inlet pump (40) and the second inlet pump (50) respectively, so that the wastewater containing nitrite in the first storage bottle (4) enters the shell (10) through the third inlet pipe (103), and the wastewater containing hydroxylamine in the second storage bottle (5) enters the shell (10) through the first inlet pipe (100); control the concentration of nitrite in the shell (10) to be 1-20 mg NL. -1 ; S3. Wastewater containing hydroxylamine is treated with 4–28 mg NL. -1 d -1 The loading rate is slow and continuous, diffused through the distributor (11) into the interior of the shell (10), and comes into contact with the flocculent sludge and anaerobic granular sludge containing denitrifying anaerobic methanogenic bacteria. The hydroxylamine in the wastewater is oxidized by the flocculent sludge and anaerobic granular sludge containing denitrifying anaerobic methanogenic bacteria to produce nitrogen gas. The wastewater carrying nitrogen gas and sludge particles passes through the three-phase separator (12), where the nitrogen gas and sludge particles are separated. Part of the wastewater enters the collection tank (3) through the first effluent pipe (101) and the other part enters the interior of the filter membrane (23) through the second effluent pipe (200). The concentration of hydroxylamine in the effluent from the first effluent pipe (101) and the second effluent pipe (102) is controlled to be less than 0.2 mg N L. -1 ; S4. A mixture of 95% methane and 5% carbon dioxide from the gas storage cylinder (6) is introduced into the filter membrane (23) through the first inlet pipe (202) and the second inlet pipe (203), respectively. The pressure inside the filter membrane (23) is adjusted to 80 kPa by the pressure valve (60) to accelerate the dissolution rate of methane in the wastewater. The wastewater containing dissolved methane is discharged through the third outlet pipe (201) and enters the shell (10) through the first inlet pipe (100) under the action of the circulation pump (24). S5. Repeat steps S3 and S4 until the water effluent from the third outlet pipe (201) meets the discharge requirements; The expanded granular sludge bed system includes a reactor body (1), a membrane module (2) connected to the reactor body (1), a water collection tank (3), a first liquid storage bottle (4), a second liquid storage bottle (5), and a gas storage bottle (6) connected to the membrane module (2); The reactor body (1) includes a shell (10), a water distributor (11) disposed at the bottom of the shell (10), and a three-phase separator (12) disposed at the top of the shell (10); the water distributor (11) is connected to a second storage bottle (5) through a first inlet pipe (100); the three-phase separator (12) is connected to a water collection tank (3) through a first outlet pipe (101) and to a membrane module (2) through a second outlet pipe (102); the first storage bottle (4) is connected to the interior of the shell (10) through a third inlet pipe (103); The membrane assembly (2) includes an outer cylinder (20), a sealing plate (21) disposed at the lower end of the inner cavity of the outer cylinder (20), a bracket (22) disposed inside the outer cylinder (20) and connected to the sealing plate (21), and a filter membrane (23) sleeved on the bracket (22); the outer cylinder (20) is connected to the second water outlet pipe (102) through the second water inlet pipe (200), and is connected to the first water inlet pipe (100) through the third water outlet pipe (201), and is connected to the gas storage bottle (6) through the first air inlet pipe (202) and the second air inlet pipe (203) respectively.

2. The method for treating wastewater by hydroxylamine oxidation based on an expanded granular sludge bed system according to claim 1, characterized in that, The water distributor (11) includes two annular pipes (110) that are nested together and interconnected, and several water distribution branch pipes (111) that are equidistantly distributed on the bottom surface of the two annular pipes (110); the first water inlet pipe (100) is connected to the annular pipe (110) located on the inner side.

3. The method for treating wastewater by hydroxylamine oxidation based on an expanded granular sludge bed system according to claim 1, characterized in that, A buffer assembly (7) is provided inside the housing (10). The buffer assembly (7) includes a rotating sleeve (70) that is rotatably engaged inside the housing (10) and a buffer disk (71) provided at the bottom end of the rotating sleeve (70). A conical gear ring (72) is provided on the upper end of the side wall of the rotating sleeve (70). A return spring (700) that abuts against the side wall of the rotating sleeve (70) is provided on the inner wall of the housing (10). Several inclined actuating plates (710) are evenly distributed on the bottom surface of the buffer disk (71), and the inclination directions of two adjacent actuating plates (710) are opposite. A drive motor (73) is provided on the side wall of the housing (10). The output shaft of the drive motor (73) passes through the housing (10), and an incomplete bevel gear (730) that meshes with the conical gear ring (72) is provided on the output shaft.

4. The method for treating wastewater by hydroxylamine oxidation based on an expanded granular sludge bed system according to claim 1, characterized in that, The sealing plate (21) is slidably engaged with the outer cylinder (20) and rotatably engaged with the end cap (220). A damping spring (204) is provided on the inner wall of the outer cylinder (20) to abut against the bottom surface of the sealing plate (21). Several rotating rods (222) are evenly distributed around the two end caps (220). A spiral groove (205) is provided on the inner wall of the outer cylinder (20) to slidably engage with each of the rotating rods (222). An impact blade (25) is provided on the end cap (220) located at the top of the support rod (221).

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