A device and method for sulfur autotrophic denitrification nitrogen removal

Abstract

This invention belongs to the field of denitrification filter technology, and discloses a sulfur autotrophic denitrification device and its treatment method. The filter media rack includes a central tube, a filter media box, and an outer cover. The central tube drives the outer cover to rotate, generating a water flow that flushes the inner wall of the tank. The filter media box is hinged to the side opening of the outer cover near the central tube, and the outer cover drives the filter media box to rotate to filter the wastewater in the tank. The filter media box contains filter media units, and sulfur autotrophic denitrifying microorganisms form a biofilm on the surface of the filter media units. When the filter media units become clogged, the filter media box deforms to change the gaps between the filter media units and generate a water flow that flushes the filter media units. During filter media cleaning, the blockages are collected in a sludge collection mechanism for thorough removal of solid blockages. By optimizing the flushing method and the filter media stacking state, a lower flushing water flow can be used to clean the filter media, reducing unnecessary loss of the biofilm caused by high-speed water flushing.

Description

Technical Field

[0001] This invention relates to the field of denitrification filter technology, specifically to a sulfur autotrophic denitrification device and its treatment method. Background Technology

[0002] Sulfur autotrophic denitrification is a wastewater treatment process that uses sulfur autotrophic denitrifying microorganisms as the main bacteria to form a biofilm on the packing material for reduction and denitrification. The sulfur autotrophic denitrifying microbial biofilm uses reduced sulfur sources such as sodium sulfide, elemental sulfur, and sodium thiosulfate as electron donors, and carbonate ions, bicarbonate ions, and carbon dioxide as inorganic carbon sources. Under anoxic conditions, it reduces nitrite or nitrate nitrogen to nitrogen gas. Traditional biofilm wastewater treatment processes rely on biological filters and supporting facilities.

[0003] In the process of sulfur autotrophic denitrification, solid blockages are generated due to the denitrification reaction and the aging and shedding of the biofilm, which block the filter media and cause head loss. In order to allow wastewater to pass through smoothly, the filter media needs to be cleaned. The existing filter media cleaning method is to use backwash water to flush the filter media from the bottom. The water level in the filter tank rises above the top slag discharge port of the filter tank. The solid blockages dispersed in the water will overflow and be discharged with the backwash water. When the backwashing is over and no more water is added, the water in the filter tank will no longer overflow from the slag discharge port. The solid blockages that are not discharged with the backwash water will remain in the biological filter tank. In view of this, there is an urgent need for a sulfur autotrophic denitrification device and treatment method. Summary of the Invention

[0004] The purpose of this invention is to provide a device and method for sulfur autotrophic denitrification and nitrogen removal, which can solve technical problems in actual production:

[0005] When the filter media is backwashed, the solid blockages that are washed off are not discharged in a concentrated manner, which will cause some of the solid blockages to remain in the biological filter, resulting in incomplete cleaning.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: It includes a tank body, within which a filter media rack is provided in a cylindrical cavity. The filter media rack comprises a central tube, a filter media box, and an outer cover. The outer cover is fixed to the circumferential side wall of the central tube and rotatably coaxially connected to the tank body. A filter media box is hinged to the side opening of the outer cover near the central tube. The internal space of the outer cover is connected to the outside via a drain pipe. The filter media box contains filter media units, and sulfur-autotrophic denitrifying microorganisms form a biofilm on the surface of the filter media. The filter media box deforms under pressure, changing the filter media accumulation gap. A sludge collection mechanism is installed on the inner wall of the movable end of the filter media box. The filter media box and the sludge collection mechanism deform and communicate with the central tube to form a parallel water flow that scours the filter media. The deformation of the sludge collection mechanism causes the filter media box to form a sludge cleaning channel through the sludge collection mechanism and the communicating central tube. Secondary wastewater in the tank washes the filter media and discharges from the sludge cleaning channel. The central tube backflushes and cleans the sludge cleaning channel, causing the filter media box and the sludge collection mechanism to deform and reset.

[0007] Preferably, the filter media box includes a rubber plate and a shell. One end of the shell is hinged to the central tube via a connecting sleeve, and the other end of the shell is movably connected to the outer cover via the rubber plate. The filter media is arranged inside the filter media box through a partitioned mesh.

[0008] Preferably, the filter media unit includes a partitioned mesh, which divides to form a continuous receiving cavity. The receiving cavity is filled with filter media particles. A curtain is provided at one end of the partitioned mesh near the central tube. When the shell is in the unfolded state, secondary wastewater can flow from the curtain into the filter media box.

[0009] Preferably, the housing includes a first filter housing and a second filter housing. When the first and second filter housings are closed, the rubber plate is folded and squeezed against the inner wall of the outer cover. The water pressure difference on both sides of the housing increases, causing the first and second filter housings to swing and unfold towards the inner side of the outer cover and drive the rubber plate to straighten. The fine holes on the rubber plate are directly opposite the drain pipe opening. The secondary wastewater washes along the surface of the second filter housing and accelerates the flushing of the drain pipe opening through the fine holes.

[0010] Preferably, the top and bottom of the first and second filter shells are provided with interconnected water passages and confluence chambers. The sludge collection mechanism includes two collection shells, with a spring connecting the two collection shells. The end of each collection shell has an end hole. When the first and second filter shells are closed, the collection shells disconnect the two water passages from the filter media box. When the first and second filter shells are unfolded, the collection shells connect the two water passages to the filter media box.

[0011] Preferably, the middle tube includes a vertical cavity, which is connected to two water passages through two connecting sleeves. The top of the middle tube is provided with a backwash port, and the bottom of the middle tube is provided with a drain port. When the first and second filter shells are in the unfolded state, the secondary wastewater that enters the vertical cavity through the water passages and connecting sleeves is discharged from the backwash port and the drain port.

[0012] Preferably, the top of the vertical cavity is provided with a partition, and a swing plate is hinged to the top of the partition. A water-blocking component is hinged to the bottom of the vertical cavity at the partition. The water-blocking component is connected to the end of the second filter shell near the middle tube by a pull rope and a drawstring. When the first and second filter shells unfold, the water-blocking component swings upward, dividing the vertical cavity into upper and lower parts. The backwash port provides backwash water, which is guided by the swing plate and the partition to flush the support plate of the water-blocking component, causing the water-blocking component to swing downward. The water-blocking component drives the first and second filter shells to gradually approach each other through the drawstring. During the approach of the first and second filter shells, the backwash water enters the collection shell through the upper water passage for rinsing and returns to the lower part of the vertical cavity through the lower water passage and is discharged from the drain port until the first and second filter shells are completely closed, thus disconnecting the water passage from the collection shell.

[0013] Preferably, the collecting shell has an opening facing the central tube, and a separator is hinged at the opening. The separator includes a baffle, and a secondary plate is installed on one side of the baffle. The angle between the secondary plate and the baffle forms a collecting part, which blocks the solids entering the collecting shell from flowing out. The top of the secondary plate bends toward the baffle to form an inclined guide part. The backwash water flowing from top to bottom impacts the inclined guide part and closes the opening.

[0014] Preferably, the top of the tank is provided with a sealing cover, which has a secondary wastewater inlet and an exhaust outlet.

[0015] Preferably, a method for secondary wastewater denitrification treatment using a sulfur autotrophic denitrification denitrification device includes the following steps:

[0016] S1. Introduce pre-cultured and acclimated activated sludge containing sulfur autotrophic denitrifying microorganisms into the tank. Inoculate the filter media in the filter box through indirect biofilm formation. Because the autotrophic denitrification process using sulfides as electron donors may result in the toxicity of sulfides inhibiting the microorganisms in the system, leading to low treatment efficiency and reduced treatment capacity, the sludge acclimation during the start-up period is very important. It is necessary to continuously improve the tolerance of microorganisms to sulfide toxicity and cultivate and acclimate sulfur autotrophic denitrifying microorganisms to ensure the stable operation of the system and enable the added sulfur autotrophic denitrifying microorganisms to successfully form a biofilm on the filter media and partition screen.

[0017] S2. By adding a pretreatment tank before the tank inlet, which can be set up separately, the nitrogen-containing wastewater to be introduced into the tank is pretreated. The pH value and S / N are adjusted by adding reagents and reduced sulfur source. The suitable pH value for sulfur autotrophic denitrifying microorganisms is about 7.0, and the reasonable S / N ratio for the sulfur autotrophic denitrification process is 5:2. By introducing heat source and cold source, the temperature of nitrogen-containing wastewater is adjusted so that the sulfur autotrophic denitrifying microorganisms are in a suitable temperature state of about 30°C. This ensures that the secondary wastewater entering the tank has suitable water temperature, S / N and pH conditions, avoiding large fluctuations in the environmental conditions related to the survival of sulfur autotrophic denitrifying microorganisms, which could lead to the collapse and detachment of the sulfur autotrophic denitrifying microorganism biofilm in the tank.

[0018] S3. The secondary wastewater entering the tank comes into contact with the filter media unit and the sulfur autotrophic denitrifying microbial biofilm in the filter media box. The sulfur autotrophic denitrifying microbial biofilm uses reduced sulfur source as electron donor and carbonate ions, bicarbonate ions, and carbon dioxide as inorganic carbon source. In an oxygen-deficient environment, it reduces nitrite or nitrate nitrogen to nitrogen gas, which is discharged from the exhaust port at the top of the tank.

[0019] S4. As the reaction continues, the sulfate produced in the denitrification reaction will be converted into solid sulfides in the tank through biochemical reactions. In addition, the aging and shedding of the sulfur autotrophic denitrifying microbial biofilm will accumulate in the gaps between the filter media particles, forming blockages, leading to filter media blockage and head loss.

[0020] S5. After the hydraulic retention time and secondary wastewater quality meet the discharge requirements, open the drain pipe to allow the secondary wastewater in the tank to flow through the filter media box and then be discharged. Check the head loss of the filter media unit by rotating the filter media frame. If the water flow rate of the filter media box drops beyond the design limit, the water pressure difference on both sides of the filter media box will cause the shell to detach from the rubber plate and unfold. At this time, some secondary wastewater will flow in from the opened curtain to flush the blockage to the sludge accumulation mechanism and flow to the middle pipe for discharge. At the same time, some secondary wastewater will flush and clean along the mesh plate on the surface of the second filter shell. This part of the water flow will accelerate the flushing of the drain pipe opening through the fine holes to complete the cleaning of the drain pipe opening.

[0021] S6. The partitioned mesh serves as a carrier for the growth of sulfur-autotrophic denitrifying bacteria. It has a high specific surface area. The layered arrangement reduces the compressive strength of the lower packing. When the partitioned mesh is relaxed, it expands and increases the gap between the filter media and the partitioned mesh. The horizontal water flow generated by the rotation of the filter media frame can flush and clean the blockages in the filter media, replacing the high-pressure backwash water to flush the filter media from bottom to top. This can reduce unnecessary loss of biofilm on the surface of the packing during backwashing.

[0022] S7. Backwash water will be introduced into the central tube to remove blockages in the central tube and the sludge accumulation mechanism. At this time, the backwash water is blocked by the baffle and will not act on the filter media. It can also drive the filter media box to reset and carry out subsequent water treatment operations normally.

[0023] S8. The treated water discharged from the tank will enter the flocculation tank and disinfection tank for solid removal and to kill pathogens and viruses before being discharged.

[0024] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0025] 1. Through the design of the sludge collection mechanism and the water baffle, during the filter media cleaning process, the blockages are collected in the sludge collection mechanism. By improving the structure of the opening of the sludge collection mechanism, the blockages that enter the sludge collection mechanism are less likely to flow out. During the backwashing of the sludge collection mechanism, the backwash water flow can close the inlet of the sludge collection mechanism with the water baffle, preventing the collected solid blockages from returning to the filter media and ensuring the complete discharge of solid blockages. Furthermore, the backwash water acting on the water baffle can reset the filter media box, allowing for subsequent normal denitrification reaction operations.

[0026] 2. By setting up the filter media rack and filter media box, when the head loss is large, the water pressure difference on both sides of the filter media box causes the filter media box to deform automatically. The rotation of the filter media rack causes the secondary waste water to flow horizontally through the layered filter media in the filter media box for short-distance flushing. The deformation of the filter media box increases the gap between the filter media in the box, improving the passage rate of blockages. By optimizing the flushing method and the filter media stacking state, a lower flushing water flow can be used to clean the filter media, reducing unnecessary loss of the biofilm caused by high-speed water flushing. Attached Figure Description

[0027] Figure 1 This is a three-dimensional schematic diagram of the entire invention;

[0028] Figure 2 This is a schematic diagram of the overall internal structure of the present invention;

[0029] Figure 3 This is a cross-sectional schematic diagram of the present invention;

[0030] Figure 4 This is a schematic diagram showing the positions of the filter media box and the filter media frame during operation according to the present invention;

[0031] Figure 5 This is an enlarged schematic diagram of the first filter housing of the filter media box of the present invention;

[0032] Figure 6 This is a schematic diagram showing the positions of the filter media box, water baffle, and filter media frame in their working states according to the present invention.

[0033] Figure 7 This is a schematic diagram showing the position between the first filter housing and the filter media of the present invention;

[0034] Figure 8This is an enlarged view of the working state between the water-blocking component and the filter media frame of the present invention;

[0035] Figure 9 This is a schematic diagram showing the positions of the sludge collection mechanism and the filter media box during operation according to the present invention;

[0036] Figure 10 This is a schematic diagram showing the position of the filter media box in its self-cleaning state according to the present invention;

[0037] Figure 11 This is a schematic diagram showing the position of the filter media box and the sludge collection mechanism in a self-cleaning state according to the present invention;

[0038] Figure 12 This is an enlarged view of the water-blocking component and the filter media holder in a self-cleaning state according to the present invention.

[0039] Figure 13 This is an enlarged view of the backflow state between the water-blocking component and the filter media frame of the present invention.

[0040] Figure 14 This is a diagram showing the position of the baffle of the slag accumulation mechanism of the present invention in the working state and the self-cleaning state;

[0041] Figure 15 This is a position diagram of the baffle of the slag accumulation mechanism of the present invention in the backflush state.

[0042] In the diagram: Tank 1, Cylindrical cavity 11, Pipe fitting 12, Filter media rack 2, Outer cover 21, Bevel 211, Drain pipe 22, Middle pipe 23, End block 231, Vertical cavity 232, Backflush port 233, Connecting sleeve 24, Filter media box 3, First filter shell 31, Water passage 311, Second filter shell 32, Manifold 321, Rubber plate 33, Support rod 331, Fine hole 332, Water passage hole 34, Connecting pipe 35. Partition net 4. Curtain 41. Receiving cavity 42. Slag accumulation mechanism 5. Collection shell 51. Baffle 52. Spring piece 53. End hole 54. Sub-plate 55. Inclined guide 551. Port 552. Fin 56. Protruding edge 561. Gathering part 57. Water blocking part 6. Pull rope 61. Gathering belt 611. Partition 62. Arc-shaped part 621. Swing plate 622. Guide block 63. Cavity 64. Support plate 65. Detailed Implementation

[0043] Example 1

[0044] In this embodiment, a sulfur autotrophic denitrification denitrification device is provided, which mainly includes a tank 1. A filter rack 2 is provided in the cylindrical cavity 11 of the tank 1, and a sealing cover is provided on the top of the tank 1. The sealing cover is provided with a secondary wastewater inlet and an exhaust port. The secondary wastewater inlet can be used to introduce secondary wastewater, the sealing cover provides an anaerobic environment, and the exhaust port can balance the internal and external gas pressure difference during the reaction.

[0045] Regarding filter rack 2, please refer to... Figure 3 , 4 9. The filter media rack 2 includes a central tube 23, a filter media box 3, a sludge collection mechanism 5, and an outer cover 21. Multiple annular arrays of outer covers 21 are fixed to the circumferential sidewall of the central tube 23. A motor is installed on the top of the central tube 23 to drive the rotation of the central tube 23 and the outer covers 21. Because the central tube 23 is coaxially connected to the tank 1, and the end of the outer cover 21 slides against the inner wall of the tank 1, during the denitrification reaction, the rotation of the central tube 23 can drive the outer covers 21, disturbing the secondary wastewater inside the tank 1. Due to the rotation of the outer covers 21, the inner wall of the outer covers 21 will... The wastewater is propelled towards the tank 1 by centrifugal force, and the secondary wastewater flows out from the filter box 3 near the inner wall of the tank 1, flushing the inner wall of the tank 1 and preventing solid debris from adhering to the inner wall of the tank 1. At the same time, after impacting the inner wall of the tank 1, the secondary wastewater is rebounded and flows towards the central pipe 23, and then flows through the filter box 3 again from the position near the central pipe 23 into the outer cover 21, so that the secondary wastewater can fully contact the filter box 3. The rotation of the outer cover 21 causes the secondary wastewater to repeatedly pass through the filter box 3, so that all the secondary wastewater can contact the filter box 3.

[0046] Regarding outer cover 21, refer to... Figure 3 The outer cover 21 has a side opening on its vertical side wall that is the same height as the body of the outer cover 21, and a filter box 3 is hinged and installed near the central tube 23, as shown in the figure. Figure 4 The filter media box 3 contains a filter media unit. A perforated plate is embedded in the center of the filter media box 3, allowing secondary wastewater to flow to the filter media unit. The filter media unit provides a carrier for the attachment of sulfur-autotrophic denitrifying microorganisms. The filter media includes a porous carrier with a high specific surface area and an ordered mesoporous channel structure. As a carrier for the growth of sulfur-autotrophic denitrifying bacteria, this facilitates the attachment and growth of the sulfur-autotrophic denitrifying microbial community, increasing the biomass within the system. (Refer to...) Figure 4 The internal space of the outer cover 21 is connected to the external drain pipe 22. After the hydraulic retention time is reached or the secondary wastewater quality meets the requirements, the drain pipe 22 can be opened to discharge the secondary wastewater in the tank 1. During the drainage process, the filter box 3 filters the secondary wastewater discharged from the outer cover 21, so that large particulate solid impurities in the secondary wastewater can be collected between the filter units.

[0047] Meanwhile, regarding filter media box 3, refer to Figure 4 The filter media box 3 includes a rubber plate 33 and a housing. When the filter media box 3 rotates synchronously with the filter media frame 2 to filter secondary wastewater, the rubber plate 33 is folded and pressed between the inner wall of the housing and the outer cover 21. Through elastic deformation, the position between the housing and the outer cover 21 is relatively stable, and solid blockages are collected in the filter media box 3. (Refer to...) Figure 10The housing includes a first filter housing 31 and a second filter housing 32. One end of a rubber sheet 33 is connected to the outer cover 21, and the other end is connected to the first filter housing 31. A support rod 331 is installed on the end of the second filter housing 32 facing the rubber sheet 33, and the rubber sheet 33 is installed through the gap between the support rod 331 and the second filter housing 32. When the rubber sheet 33 is folded in half, the support rod 331 is located at the center line of the rubber sheet 33. At this time, refer to... Figure 9 A sludge collection mechanism 5 is installed on the inner wall of the filter media box 3 at the end away from the central tube 23. The sludge collection mechanism 5 includes two collection shells 51, and a spring piece 53 connects the two collection shells 51. End holes 54 are opened at the top and bottom ends of the collection shells 51. (Refer to...) Figure 5 The first filter shell 31 and the second filter shell 32 are provided with interconnected water passage channels 311 and confluence chambers 321 at their top and bottom positions. Water passage channels 311 and confluence chambers 321 are provided with water passage holes 34 facing the collection shell 51, and the end holes 54 and water passage holes 34 are staggered. At this time, the secondary wastewater can only pass through the first filter shell 31 and the second filter shell 32 and cannot enter the water passage channels 311 and confluence chambers 321.

[0048] It should be noted that when excessive solid debris accumulates in the filter media box 3, causing blockage, the filter media frame 2 continues to rotate the filter media box 3. The filter media unit in the filter media box 3 experiences reduced water flow rate due to blockage, and secondary wastewater cannot pass through the blocked filter media box 3. This causes the filter media box 3 to overcome the elasticity of the rubber plate 33 and swing around the connecting sleeve 24 towards the inside of the outer cover 21. (Refer to...) Figure 10 One end of the housing is hinged to the middle tube 23 via the connecting sleeve 24. At this time, the rubber plate 33 will be straightened because the first filter shell 31 and the second filter shell 32 are hinged to each other at the end near the rubber plate 33. The rubber plate 33 presses the connecting rod 331 at the end of the second filter shell 32, so that the ends of the first filter shell 31 and the second filter shell 32 near the middle tube 23 will move away from each other and unfold.

[0049] At this time, refer to Figure 11 As the first filter housing 31 and the second filter housing 32 unfold, the previously compressed and deformed spring sheet 53 is released, which in turn causes the collection housing 51 to swing, making the end hole 54 and the water passage hole 34 interconnected. Please refer to [the relevant documentation]. Figure 10 The partition mesh 4 is designed in a fan shape to ensure that the first filter shell 31 and the second filter shell 32 can be smoothly unfolded into a fan shape. A vertical curtain 41 is provided at one end of the partition mesh 4 near the central tube 23. The curtain 41 is unfolded when the first filter shell 31 and the second filter shell 32 are unfolded. At this time, as the central tube 23 rotates, some secondary wastewater flows from the curtain 41 into the filter media box 3 to flush the internal filter media units, and solid blockages are flushed to the sludge collection mechanism 5 for unified collection. At this time, the secondary wastewater in the filter media box 3 can enter the water passage 311 and the manifold 321 into the central tube 23 and exit from the backflushing hole 233 at the top of the central tube 23 and the drain outlet at the bottom, discharging some solid blockages. (Refer to...) Figure 9The water passage 311 and the manifold 321 are connected in series by a connecting pipe 35, as shown in the reference. Figure 7 The water passage 311 and the connecting sleeve 24 are interconnected and connected to the vertical cavity inside the middle pipe 23. The backflush hole 233 and the sewage outlet are rotatably connected to the pipe fitting 12, which can collect the discharged secondary wastewater.

[0050] At the same time, as the filter media box 3 rotates, some of the secondary wastewater flows along the water-facing surface of the mesh plate of the second filter shell 32, and performs horizontal flushing and cleaning of the mesh plate of the second filter shell 32. At this time, the fine holes 332 on the rubber plate 33 are exposed and are directly facing the opening of the drain pipe 22. The secondary wastewater flowing towards the rubber plate 33 will be accelerated through the fine holes 332. When the secondary wastewater is discharged from the drain pipe 22, the opening of the drain pipe 22 is flushed and cleaned.

[0051] Reference Figure 7 The filter media unit includes a partitioned mesh 4 and filter media particles. The partitioned mesh 4 is flattened by the unfolding of the first filter shell 31 and the second filter shell 32, which can expand the filter media particles that are squeezed together, thus widening the gaps between the filter media particles. When the secondary wastewater flows horizontally, it can flush the blockages between the filter media to the sludge collection mechanism 5 for unified collection. The partitioned mesh 4 has multiple flat mesh plates stacked vertically, and vertically intersecting inclined mesh plates are set on the top surface of the flat mesh plates, which can divide the space between the flat mesh plates to form a continuous receiving cavity 42. The horizontally flowing secondary wastewater will horizontally flush the filter media and partitioned mesh 4 along the radial direction of the tank 1, which can flush the filter media between the flat mesh plates in layers. Furthermore, because along the radial direction of the tank 1 The water flows horizontally, so the path of the water flow is shorter than that of vertical backwashing, resulting in a smaller decrease in water flow velocity due to obstruction by filter media particles. At the same time, the water is carried through water channels 311 and central pipe 23 and discharged from tank 1, completing the horizontal rinsing of the filter media particles. Compared with traditional vertical backwashing, this method, which generates parallel water flow in the vertical direction by rotating the filter media frame 2, expands the filter media box 3 to increase the gap between the filter media and improve the water permeability and the passage rate of blockages, and shortens the rinsing stroke in the radial direction by parallel water flow, requires a slower rinsing water flow speed while ensuring clean rinsing. This can reduce the shedding of the biofilm caused by backwashing, ensure the stability of the biofilm of sulfur autotrophic denitrifying microorganisms, and avoid unnecessary losses.

[0052] When rinsing the filter media unit with secondary wastewater, as the first filter housing 31 and the second filter housing 32 unfold, the retaining belt 611 is pulled, causing the water-blocking component 6 to swing upwards. At this time, the water-blocking component 6 is in a horizontal position at the bottom. (Refer to...) Figure 12 A water-blocking component 6 is hinged to the bottom of the partition 62. The water-blocking component 6 is a quarter-cylinder and refers to... Figure 13A concave cavity 64 is formed in the circumferential sidewall, and a ring array of support plates 65 is installed at the opening of the cavity 64. The support plates 65 extend radially along the water-blocking member 6, and the water-blocking member 6 is connected to the end of the second filter shell 32 by a soft rope. (Refer to...) Figure 8 The soft rope includes a pull rope 61 and a drawstring 611. The pull rope 61 is made of nylon. One end of the pull rope 61 is fixed to the top of the water-blocking component 6, and the other end of the pull rope 61 is connected to the drawstring 611. A round hole is made in the side wall of the central tube 23 to allow the pull rope 61 to slide through. The drawstring 611 is a relatively wide strip, and a through-hole is made in the middle of the first filter shell 31 near the central tube 23 for the drawstring 611 to pass through. Please refer to [reference needed]. Figure 12 The end of the retractable band 611 will be fixed to the end of the second filter housing 32 near the middle tube 23;

[0053] After the filter media unit is rinsed with secondary wastewater, some solid blockages are concentrated in the sludge accumulation mechanism 5. Water is supplied to the backwash port 233 through the upper pipe 12 to backwash the sludge accumulation mechanism 5 and the water passage 311. The water baffle 6 is impacted by the backwash water and swings downwards until its top surface is horizontal, thus blocking the water passage 311. At this point, the backwashing stops. After the secondary wastewater is discharged from the tank 1, water is supplied to the backwash port 233 through the upper pipe 12. A partition assembly is provided at the top of the vertical cavity, see reference. Figure 13 The partition assembly includes a fixed partition 62 and a swing plate 622 hinged to the top of the partition 62. Backwash water entering the backwash port 233 impacts the swing plate 622, causing the backwash water to be guided downwards by the partition 62 and the swing plate 622. The bottom of the partition 62 is designed with an arc-shaped portion 621, which narrows the flow path, allowing the backwash water to impact the upper surface of the support plate 65 at high speed. By installing a guide block 63 slightly below the opposite side of the water-blocking member 6, the backwash water impacting the support plate 65 can only enter the upper water passage 311 through the cavity 64. (Refer to...) Figure 11 Then, water enters the collection shell 51 through the top water passage 34 and flows downwards through the internal space of the collection shell 51, as shown in the reference. Figure 5 Finally, the water flows from the end hole 54 at the bottom of the collection shell 51 into the lower water passage 311 and returns to the vertical cavity, eventually exiting the tank 1 from the drain port at the bottom of the vertical cavity, completing the backflushing of the water passage 311 and the internal space of the collection shell 51. As the water baffle 6 swings downward, refer to Figure 6 This causes the pull rope 61 to be pulled into the vertical cavity, and then the first filter shell 31 and the second filter shell 32 are gradually brought closer together by pulling the retracting strap 611. During the process, refer to Figure 9 When the collecting shell 51 is compressed, the spring piece 53 is compressed and bent, causing the water passage hole 34 on the water passage channel 311 to gradually shift away from the end hole 54 until the water baffle 6 is impacted to a horizontal state on the top surface. (Refer to...) Figure 8At this time, the water passage 311 is disconnected from the collection shell 51, and the backwash water cannot continue to enter the collection shell 51, nor can it enter the lower part of the vertical cavity through the water baffle 6. As the water passage is disconnected and the water pressure increases, it will not be able to continue to enter. At this time, the backwash water supply can be stopped.

[0054] In a further embodiment, regarding the collection shell 51, to prevent solid blockages from flowing out of the inlet and returning to the filter media unit during solid blockage collection, a baffle 52 and a secondary plate 55 are installed at the opening on the side of the collection shell 51 facing the central tube 23 to block and slow down the water flow from inside the collection shell 51 to the opening, causing the solid blockages carried in the water flow to fall and deposit inside the collection shell 51. (Refer to...) Figure 14 The separator includes multiple vertically arranged baffles 52. When water flows horizontally into the collection shell 51, the baffles 52 rotate around their axes. Because a secondary plate 55 is installed at a certain angle to the baffle 52 in the vertical position, a collection part 57 with an opening facing the inside of the collection shell 51 is formed between the baffle 52 and the secondary plate 55. The water flow that is bounced off the inner wall of the collection shell 51 is intercepted and slowed down at this point, so that the entrained blockage remains in the collection part 57, preventing solid impurities from flowing out of the collection shell 51. Furthermore, an elastic fin 56 is installed in the middle of the secondary plate 55 in a direction away from the baffle 52. The end of the fin 56 has a protruding edge 561. The water flow from the filter media box 3 impacts the fin 56. This will cause the secondary plate 55 and the baffle 52 to swing synchronously towards the baffle 52. When the fin 56 is blocked by the baffle 52 and cannot be directly impacted by the water flow, the baffle 52, which has a larger contact area with the water flow, will swing towards the secondary plate 55 under the impact of the water flow. This reciprocating swing can change the direction of the water flow impacting the inner wall of the collection shell 51, so that the water flow is turbulent and slowed down inside the collection shell 51, reducing the ability to carry blockages, so that the blockages are concentrated at the bottom, reducing the number of blockages entering the upper water passage 311, reducing the difficulty of backwashing, and expanding the coverage of the collection part 57, ensuring that more water flow rebounded by the inner wall of the collection shell 51 is captured, further keeping the blockages inside the collection shell 51.

[0055] During backwashing, the backwash water flowing out of the upper water passage 311 impacts the inclined guide portion 551 at the end of the sub-plate 55, causing the baffle 52 to swing towards the opening of the collection shell 51 and eventually close the opening, preventing solid blockages inside the collection shell 51 from re-entering the filter media unit. (Refer to...) Figure 15The backwash water will be guided by the inclined guide 551 at the end of the sub-plate 55, and the backwash water will act on the inclined guide 551, causing the baffle 52 to swing toward the opening of the collection shell 51. The movable end of the baffle 52 will be blocked by the hinged position of the adjacent collection shell 51, thereby closing the opening of the collection shell 51. This will allow the backwash water to enter only the water passage 311 below, and it will not enter the filter media box 3 to re-contaminate the filter media unit, thus ensuring the smooth backwashing.

[0056] In a further embodiment, regarding the partitioned mesh 4, the top of the receiving cavity 42 has a slit that can be used to replace the filter media particles. Furthermore, the upper and lower flat mesh plates can be stacked to support the filter media particles in layers, preventing the lower layer of filter media particles from being crushed and improving the service life of the filter media particles. At the same time, the upper flat mesh plate presses the slit at the top of the lower receiving cavity 42 tightly to prevent the filter media particles from leaking out.

[0057] In a further embodiment, a method for secondary wastewater denitrification treatment using a sulfur autotrophic denitrification denitrification device is disclosed, comprising the following steps:

[0058] S1. Introduce pre-cultured and acclimated activated sludge containing sulfur autotrophic denitrifying microorganisms into tank 1. Inoculate the filter media in filter box 3 by indirect biofilm formation. Because the autotrophic denitrification process using sulfides as electron donors may result in the toxicity of sulfides inhibiting the microorganisms in the system, leading to low treatment efficiency and reduced treatment capacity, the sludge acclimation during the start-up period is very important. It is necessary to continuously improve the tolerance of microorganisms to sulfide toxicity and cultivate and acclimate sulfur autotrophic denitrifying microorganisms in order to ensure the stable operation of the system and enable the added sulfur autotrophic denitrifying microorganisms to successfully form biofilms on the filter media and partitioned mesh 4.

[0059] S2. By adding a pretreatment tank before the inlet of tank 1, the pretreatment tank can be set up separately and pretreatment is performed on the nitrogen-containing wastewater that will be introduced into tank 1. The pH value and S / N are adjusted by adding reagents and reduced sulfur source. The suitable pH value for sulfur autotrophic denitrifying microorganisms is about 7.0, and the reasonable S / N for the sulfur autotrophic denitrification process is 5:2. By introducing heat source and cold source, the temperature of nitrogen-containing wastewater is adjusted so that the sulfur autotrophic denitrifying microorganisms are in a suitable temperature state of about 30 degrees Celsius. This ensures that the secondary wastewater entering tank 1 has suitable water temperature, S / N and pH conditions, and avoids large fluctuations in the environmental conditions related to the survival of sulfur autotrophic denitrifying microorganisms in the secondary wastewater, which could lead to the collapse and detachment of the sulfur autotrophic denitrifying microbial biofilm in tank 1.

[0060] S3. The secondary wastewater entering the tank 1 contacts the filter media and sulfur autotrophic denitrifying microbial membrane in the filter media box 3. The sulfur autotrophic denitrifying microbial membrane uses sodium sulfide, elemental sulfur and sodium thiosulfate as reduced sulfur sources as electron donors, and carbonate ions, bicarbonate ions and carbon dioxide as inorganic carbon sources. Under the anaerobic environment, it reduces nitrite nitrogen or nitrate nitrogen to nitrogen gas, and the nitrogen gas will be discharged from the exhaust port at the top of the tank 1.

[0061] S4. As the reaction continues, the sulfate produced in the denitrification reaction will be converted into solid sulfides in tank 1 through biochemical reaction. In addition, the aging and shedding of the sulfur autotrophic denitrifying microbial biofilm will accumulate in the gaps of the filter media unit, forming blockages, leading to filter media unit blockage and head loss.

[0062] S5. After the hydraulic retention time and secondary wastewater quality meet the discharge requirements, the drain pipe 22 is opened to allow the secondary wastewater in tank 1 to flow through the filter media box 3 and then be discharged. The head loss of the filter media unit is checked by rotating the filter media frame 2. If the water flow rate of the filter media box 3 drops beyond the design limit, the water pressure difference on both sides of the filter media box 3 will cause the shell to detach from the rubber plate 33 and unfold. At this time, some secondary wastewater flows in from the opened curtain 41 to flush the blockage to the sludge accumulation mechanism 5 and flow to the middle pipe 23 for discharge. At the same time, some secondary wastewater will be flushed and cleaned along the mesh plate on the surface of the second filter shell 32. This part of the water flow will accelerate the flushing of the drain pipe 22 opening through the fine holes 332 to complete the cleaning of the drain pipe 22 opening.

[0063] S6. The partitioned mesh 4 in the filter media unit serves as a carrier for the growth of sulfur autotrophic denitrifying bacteria. It has a high specific surface area. The layered arrangement reduces the compressive strength of the lower packing. When the partitioned mesh 4 is relaxed, it will expand and increase the gap between the filter media and the partitioned mesh 4. The horizontal water flow generated by the rotation of the filter media frame 2 can complete the flushing and cleaning of the blockage in the filter media, replacing the high-pressure backwash water flushing the filter media from bottom to top, which can reduce the unnecessary loss of the film on the surface of the packing during backwashing.

[0064] S7, the middle pipe 23 will introduce backwash water to clear the blockage in the middle pipe 23 and the sludge accumulation mechanism 5. At this time, the backwash water is blocked by the baffle 52 and will not act on the filter media unit. It can also drive the filter media box 3 to reset and carry out subsequent water treatment operations normally.

[0065] S8. The treated water discharged from tank 1 will enter the flocculation tank and disinfection tank for solid removal and to kill pathogens and viruses before being discharged.

[0066] The cultivation and acclimatization of sulfur autotrophic denitrifying microorganisms into activated sludge in these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sulfur autotrophic denitrification denitrification device, comprising a tank (1), characterized in that: The cylindrical cavity (11) of the tank (1) is provided with a filter rack (2); The filter media frame (2) includes a central tube (23), a filter media box (3), and an outer cover (21). The filter media box (3) includes a rubber plate (33) and a shell. The shell includes a first filter shell (31) and a second filter shell (32). The central tube (23) drives the outer cover (21) to rotate, generating a water flow that flushes the inner wall of the tank (1). The filter media box (3) is hinged to the side opening of the outer cover (21) near the central tube (23). The outer cover (21) drives the filter media box (3) to rotate and filter the wastewater in the tank (1). The filter media box (3) contains filter media units. Sulfate autotrophic denitrifying microorganisms form a biofilm on the surface of the filter media units. When the filter media units are blocked, the filter media box (3) deforms to change the gap between the filter media units and generate a water flow that flushes the filter media units. The middle pipe (23) includes a vertical cavity, which is connected to two water passages (311) through two connecting sleeves (24). The top of the middle pipe (23) is provided with a backflush port (233). The first filter shell (31) and the second filter shell (32) are provided with interconnected water passages (311) and confluence chambers (321) at their top and bottom positions. The sludge collection mechanism (5) includes two collection shells (51), and a spring piece (53) is connected between the two collection shells (51). The end of the collection shell (51) is provided with an end hole (54). When the first filter shell (31) and the second filter shell (32) are closed, the collection shell (51) is disconnected from the two water passages (311). When the first filter shell (31) and the second filter shell (32) are unfolded, the collection shell (51) is connected to the two water passages (311). The top of the vertical cavity is provided with a partition component, and the bottom of the partition component is hinged with a water baffle (6). The water baffle (6) is connected to the end of the second filter shell (32) by a soft rope. When the first filter shell (31) and the second filter shell (32) unfold, the water baffle (6) swings upward. The backwash port (233) provides backwash water. The backwash water enters the upper water passage (311) to flush the collection shell (51) and returns to the vertical cavity from the lower water passage (311) to be discharged from the drain port. The backwash water causes the water baffle (6) to swing downward and drives the first filter shell (31) and the second filter shell (32) to gradually approach each other until the water passage (311) and the collection shell (51) are disconnected.

2. The apparatus for sulfur autotrophic denitrification and nitrogen removal according to claim 1, characterized in that: One end of the housing is hinged to the middle tube (23) via a connecting sleeve (24), and the other end of the housing is movably connected to the outer cover (21) via a rubber plate (33).

3. The apparatus for sulfur autotrophic denitrification and nitrogen removal according to claim 2, characterized in that: The filter media unit includes a partitioned mesh (4), which is divided to form a continuous receiving cavity (42). The receiving cavity (42) is filled with filter media particles. A curtain (41) is provided at one end of the partitioned mesh (4) near the central tube (23). When the shell is unfolded, secondary wastewater can flow into the filter media box (3) from the position of the curtain (41).

4. The apparatus for sulfur autotrophic denitrification and nitrogen removal according to claim 3, characterized in that: When the first filter shell (31) and the second filter shell (32) are closed, the rubber plate (33) is folded and squeezed against the inner wall of the outer cover (21). The increase in water pressure difference on both sides of the shell causes the first filter shell (31) and the second filter shell (32) to swing and unfold towards the inside of the outer cover (21) and drive the rubber plate (33) to straighten. The fine holes (332) on the rubber plate (33) are directly opposite the opening of the drain pipe (22). The secondary wastewater washes along the surface of the second filter shell (32) and accelerates the flushing of the opening of the drain pipe (22) through the fine holes (332).

5. The apparatus for sulfur autotrophic denitrification and nitrogen removal according to claim 4, characterized in that: The bottom of the central tube (23) is provided with a drain outlet. When the first filter shell (31) and the second filter shell (32) are in the unfolded state, the secondary wastewater that enters the vertical cavity through the water passage (311) and the connecting sleeve (24) is discharged from the backwash port (233) and the drain outlet.

6. The apparatus for sulfur autotrophic denitrification according to claim 5, characterized in that: The collecting shell (51) has an opening on the side facing the central tube (23), and a partition is hinged at the opening. The partition prevents the solids entering the collecting shell (51) from flowing out. The partition is closed by the backwash water impact.

7. The apparatus for sulfur autotrophic denitrification and nitrogen removal according to claim 6, characterized in that: The tank (1) is provided with a sealing cover on the top, and the sealing cover is provided with a secondary wastewater inlet and an exhaust outlet.

8. The apparatus for sulfur autotrophic denitrification and nitrogen removal according to claim 7, characterized in that: A method for secondary wastewater denitrification treatment using a sulfur autotrophic denitrification denitrification device includes the following steps: S1. Introduce pre-cultured and acclimatized activated sludge containing sulfur autotrophic denitrifying microorganisms into the tank (1), and inoculate it into the filter media of the filter box (3) by means of indirect film attachment, so that the added sulfur autotrophic denitrifying microorganisms can attach to the filter media and the partition net (4). S2. By adding a pretreatment tank before the inlet of the tank (1), the pretreatment tank is set up separately and the nitrogen-containing wastewater to be introduced into the tank (1) is pretreated. The pH value and S / N are adjusted by adding reagents and reducing sulfur source. The suitable pH value of sulfur autotrophic denitrifying microorganisms is 7.0 and the S / N is 5:

2. By introducing heat source and cold source, the temperature of nitrogen-containing wastewater is adjusted so that the sulfur autotrophic denitrifying microorganisms are in a suitable temperature state of 30℃, so that the secondary wastewater entering the tank (1) has suitable water temperature, S / N and pH conditions. S3. The secondary wastewater entering the tank (1) comes into contact with the filter media in the filter box (3) and the sulfur autotrophic denitrifying microbial film. The sulfur autotrophic denitrifying microbial film uses sulfur as an electron donor to reduce nitrite or nitrate nitrogen to nitrogen gas in an oxygen-deficient environment. The nitrogen gas will be discharged from the exhaust hole at the top of the tank (1). S4. As the reaction continues, solid impurities in the wastewater will enter the tank (1). In addition, the aging and shedding of the sulfur autotrophic denitrifying microbial biofilm will accumulate in the gaps of the filter media to form blockages, leading to filter media blockage and head loss. S5. After the hydraulic retention time and secondary wastewater quality meet the discharge requirements, open the drain pipe (22) so that the secondary wastewater in the tank (1) flows through the filter box (3) and is discharged. Check the head loss of the filter material by rotating the filter rack (2). If the water flow rate of the filter box (3) drops beyond the design limit, the water pressure difference on both sides of the filter box (3) will cause the shell to detach from the rubber plate (33) and unfold. At this time, some secondary wastewater flows in from the opened curtain (41) to flush the blockage to the sludge accumulation mechanism (5) and flow to the middle pipe (23) for discharge. At the same time, some secondary wastewater will be flushed and cleaned along the mesh plate on the surface of the second filter shell (32). This part of the water flow will accelerate the flushing of the drain pipe (22) opening through the fine holes (332) to complete the cleaning of the drain pipe (22) opening. S6. The partition net (4) serves as a carrier for the growth of sulfur autotrophic denitrifying bacteria. The layered arrangement reduces the compressive strength of the lower packing. When the partition net (4) is relaxed, it will expand and increase the gap between the filter media and the partition net (4). The horizontal water flow generated by the rotation of the filter media frame (2) completes the flushing and cleaning of the blockage in the filter media. S7. Backwash water will be introduced into the middle pipe (23) to remove the blockage in the middle pipe (23) and the sludge accumulation mechanism (5). At this time, the backwash water is blocked by the baffle (52) and will not act on the filter media position. It can also drive the filter media box (3) to reset and carry out subsequent water treatment operations normally. S8. The treated water discharged from the tank (1) will enter the flocculation tank and disinfection tank for solid removal and killing of pathogenic microorganisms and viruses before being discharged.

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