Full-room bed-coupled biological nitrogen removal reactor

Abstract

The present invention relates to a full-bed coupled biological denitrification reactor, belonging to the technical field of sewage treatment equipment. It includes a reactor box body, in which a water distribution area, an upper fluidized bed reaction chamber, a lower fixed bed reaction chamber, a filtration area and an outlet water area are successively arranged from top to bottom. The water distribution area is connected with a water inlet pipe and a backwashing outlet water pipe. In the upper fluidized bed reaction chamber, there are heterotrophic denitrifying biological carrier fillers that can be suspended in water. In the lower fixed bed reaction chamber, there is an autotrophic denitrifying filler layer. In the filtration area, there is a filtration layer. The outlet water area is connected with an outlet water pipe, a backwashing inlet air pipe and a backwashing inlet water pipe. A stirring device is arranged in the upper fluidized bed reaction chamber. By coupling the use of heterotrophic bacteria and autotrophic bacteria, the present invention can effectively remove total nitrogen while removing suspended solids and colloids in water, reduce the carbon source dosage, have a small floor area and pool volume, and greatly reduce the investment in civil engineering, etc. The denitrification system has stable effluent, high volume load, high total nitrogen load and high denitrification efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment equipment, and specifically relates to a full-bed coupled biological denitrification reactor. Background Art

[0002] With the increasing shortage of water resources and the increasingly strict sewage treatment discharge standards, the sewage treatment technology urgently needs to be upgraded and optimized, and the sewage treatment system generally faces the urgent needs of increasing efficiency and reducing emissions and advanced treatment.

[0003] Currently, it is generally believed that the biological treatment method is the most economical and effective method for removing nitrogen pollutants in water. Nitrogen in sewage wastewater usually exists in four forms: organic nitrogen, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen. Biological denitrification is a process in which organic nitrogen and ammonia nitrogen are converted into N2 and N x O gas under the action of microorganisms. It includes two reaction processes: nitrification and denitrification. The traditional denitrification tank has a large floor area, high investment, low efficiency, large carbon source dosage, high operating cost, and the surface of the filter material is easily blocked or caked. After being blocked or caked, it cannot be cleaned and needs to be directly replaced, increasing costs. Summary of the Invention

[0004] Based on this, it is necessary to provide a full-bed coupled biological denitrification reactor for the problems of the existing technology.

[0005] To solve the problems of the existing technology, the technical solution adopted by the present invention is:

[0006] A full-bed coupled biological denitrification reactor includes a reactor box body. Inside the reactor box body, there are successively arranged a water distribution area, an upper fluidized bed reaction chamber, a lower fixed bed reaction chamber, a filtration area, and an outlet area from top to bottom. The water distribution area is connected with a water inlet pipe and a backwash outlet pipe. Inside the upper fluidized bed reaction chamber, there are heterotrophic denitrification biological carrier fillers that can be suspended in water. Inside the lower fixed bed reaction chamber, there is an autotrophic denitrification filler layer. Inside the filtration area, there is a filtration layer. The outlet area is connected with an outlet pipe, a backwash inlet pipe, and a backwash inlet air pipe. Inside the upper fluidized bed reaction chamber, there is a stirring device.

[0007] As a preference, the stirring device includes a high-paddle hyperbolic stirring impeller arranged in the middle and lower part of the upper fluidized bed reaction chamber. The high-paddle hyperbolic stirring impeller is fixedly connected with a stirring shaft, and the stirring shaft is connected with a stirring motor. The distance from the bottom of the high-paddle hyperbolic stirring impeller to the autotrophic denitrification filler layer is 0.5 - 1.0 m.

[0008] As a preference, a hydrofoil stirring paddle is fixed on the stirring shaft at the upper part of the upper fluidized bed reaction chamber. The top of the reactor box body is of an open type, and an installation frame is fixed on the top of the reactor box body. The stirring motor is fixed on the installation frame.

[0009] As a preference, a water distribution ring plate fixed on the inner wall of the reactor box body is provided in the water distribution area. A water distribution weir is fixed in the inner hole of the water distribution ring plate. A backwash water outlet weir is arranged outside the water distribution weir. The water inlet pipe communicates with the water distribution area between the water distribution weir and the backwash water outlet weir. The backwash water outlet pipe is arranged above the water distribution ring plate and communicates with the water outlet area between the backwash water outlet weir and the reactor box body. There is a height difference between the top of the water distribution weir and the top of the backwash water outlet weir.

[0010] As a preference, an intercepting screen is fixed on the top of the water distribution weir, and a reinforcing ring is fixed on the top of the intercepting screen. The water inlet pipe enters water along the tangential direction of the inner wall of the backwash water outlet weir.

[0011] As a preference, the heterotrophic denitrification biological carrier filler is modified hydrophilic group polyurethane sponge, the autotrophic denitrification filler layer is iron-sulfur composite autotrophic bacteria filler, the filtering layer is a graded cobblestone layer, there are no less than two layers in the graded cobblestone layer, and the particle size of the graded cobblestone layer gradually increases from top to bottom.

[0012] As a preference, a filter plate is arranged at the bottom of the graded cobblestone layer, a plurality of filter holes are evenly arranged on the filter plate, and a filter head is arranged in each filter hole.

[0013] As a preference, a support cylinder is arranged inside the water distribution weir. A liquid guide funnel is fixed on the top of the support cylinder. The top of the liquid guide funnel is fixed on the upper inner side wall of the water distribution weir. Liquid leakage holes are evenly arranged on the liquid guide funnel. A conical water distribution plate is fixed at the bottom of the support cylinder. Water distribution holes are evenly arranged on the water distribution plate. A downward support bend is arranged at the bottom of the water distribution plate. There is a gap between the outer side of the support bend and the inner wall of the reactor box body. A support rod is fixed on the outer side of the support bend, and the other end of the support rod is fixed to the inner wall of the reactor box body.

[0014] As a preference, a nitrate nitrogen on-line detector is arranged on the water outlet pipe. The nitrate nitrogen on-line detector is connected with a controller. A mixing pipeline is connected to the water inlet pipe. A carbon source dosing pipe is fixed at the top of the front end of the mixing pipeline. The lower end of the carbon source dosing pipe extends into the middle and lower position of the mixing pipeline. A spray nozzle is arranged on the left side of the carbon source dosing pipe. A throttling variable diameter pipe is fixed on the mixing pipeline on the left side of the spray nozzle. A conical dispersion mixing plate is arranged on the left side of the throttling variable diameter pipe. Dispersion holes are evenly arranged on the dispersion mixing plate. A reinforcing ring plate is sleeved on the outer side of the left end of the throttling variable diameter pipe. The outer side of the reinforcing ring plate is fixed to the mixing pipeline. Electric flow regulating valves and flow meters are arranged on both the water inlet pipe on the right side of the mixing pipeline and the carbon source dosing pipe. The electric flow regulating valves and the flow meters are connected with the controller.

[0015] As an optimization, the filter head includes a diversion pipeline extending into the filter holes. A fixing nut is threadedly installed on the diversion pipeline below the filter plate. A pressing cap plate is fixed to the top of the diversion pipeline. Above the pressing cap plate, there are multiple distribution rings arranged vertically. A water distribution gap is provided between adjacent distribution rings. A support rib is fixed in each water distribution gap. The upper and lower ends of the support rib are fixed to the upper and lower distribution rings respectively. Above the uppermost distribution ring, there is an upper pressing cap plate. A pressing bolt is provided on the upper pressing cap plate. The lower end of the pressing bolt is threadedly installed on the lower pressing cap plate.

[0016] The beneficial effects of the present invention compared with the prior art are as follows:

[0017] By coupling heterotrophic bacteria and autotrophic bacteria, it can effectively synergistically remove total nitrogen while removing suspended solids and colloids in water, reducing the dosage of carbon source, and preventing the excessive penetration of organic matter caused by excessive carbon source. The upper fluidized bed reaction chamber, the lower fixed bed reaction chamber, and the filter layer are arranged vertically, occupying a small area and pool volume, greatly reducing investments such as civil engineering; the effluent of the denitrification system is stable, with a high volume load, a high total nitrogen load, and a high denitrification efficiency.

[0018] Using the coupled structure of double-chamber heterotrophic bacteria and autotrophic bacteria, the filter media particles do not need to be set too small, reducing the risk of blockage or hardening on the surface of the filter media. And by setting the backwashing structure, the filter layer and the autotrophic denitrification filler layer can be backwashed, which is more convenient for cleaning. During backwashing, first, air is used for backwashing to loosen the filter layer and the autotrophic denitrification filler layer, then water and gas are mixed for backwashing, and finally, separate water is used for backwashing to improve the backwashing effect.

[0019] A filter layer is arranged between the autotrophic denitrification filler layer and the water outlet area, which can prevent the leakage of the autotrophic denitrification filler layer during water treatment and can disperse the backwashing gas and water during backwashing, better distributing gas and water and improving the backwashing effect.

[0020] Using the coupled structure of double-chamber heterotrophic bacteria and autotrophic bacteria, the sewage is first treated by heterotrophic bacteria and then by autotrophic bacteria, which can ensure the alkalinity of the discharged water after treatment, thereby reducing the dosage cost of alkalinity agents and saving costs. Description of the Drawings

[0021] Figure 1 is the structural schematic diagram of the present invention;

[0022] Figure 2 is Figure 1 the partial structural schematic Figure 1 ;

[0023] Figure 3 is Figure 1 the partial structural schematic Figure 2 ;

[0024] Figure 4It is a schematic diagram of the installation structure of the liquid guiding funnel;

[0025] Figure 5 It is Figure 4 a partial structure schematic diagram of;

[0026] Figure 6 It is a schematic diagram of the connection structure of the mixing pipeline;

[0027] Figure 7 It is Figure 6 a partial structure schematic diagram of;

[0028] Figure 8 It is a schematic diagram of the structure of the filter head.

[0029] The reference numerals in the figure are:

[0030] 1. Stirring motor; 2. Mounting frame; 3. Intercepting screen; 4. Reactor box body; 5. Backwashing water outlet weir; 6. Water inlet pipe; 7. Water distribution ring plate; 8. Upper fluidized bed reaction chamber; 9. Hydrofoil stirring paddle; 10. Heterotrophic denitrification biological carrier filler; 11. Autotrophic denitrification filler layer; 12. Lower fixed bed reaction chamber; 13. Filtration area; 14. Filter layer; 15. Backwashing water inlet pipe; 16. Outlet pipe; 17. Backwashing air inlet pipe; 18. Water outlet area; 19. Filter head; 191. Upper pressing cap plate; 192. Compression bolt; 193. Support rib; 194. Distribution ring; 195. Water distribution gap; 196. Lower pressing cap plate; 197. Diversion pipeline; 198. Fixed nut; 20. Filter plate; 21. High-paddle hyperbolic stirring impeller; 22. Water distribution area; 23. Backwashing water outlet pipe; 24. Water distribution weir; 25. Reinforcing ring; 26. Stirring shaft; 27. Support cylinder; 28. Liquid guiding funnel; 29. Support rod; 30. Water dividing plate; 31. Mixing pipeline; 32. Spray nozzle; 33. Carbon source dosing pipe; 34. Electric flow regulating valve; 35. Flowmeter; 36. Throttling reducer; 37. Reinforcing ring plate; 38. Dispersion mixing plate; 39. Support bending. Specific embodiments

[0031] To further understand the features, technical means, specific purposes, and functions achieved by the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] Example 1, refer to Figures 1 to 8, A full-chamber bed coupled biological denitrification reactor, comprising a reactor box body 4. Inside the reactor box body 4, there are successively arranged a water distribution area 22, an upper fluidized bed reaction chamber 8, a lower fixed bed reaction chamber 12, a filtration area 13 and an outlet water area 18 from top to bottom. The water distribution area 22 is connected with a water inlet pipe 6 and a backwashing outlet water pipe 23. Inside the upper fluidized bed reaction chamber 8, there are heterotrophic denitrifying biological carrier fillers 10 that can be suspended in water. Inside the lower fixed bed reaction chamber 12, there is an autotrophic denitrifying filler layer 11. Inside the filtration area 13, there is a filtration layer 14. The outlet water area 18 is connected with an outlet water pipe 16, a backwashing inlet air pipe 17 and a backwashing inlet water pipe 15. There is a stirring device inside the upper fluidized bed reaction chamber 8.

[0033] During operation, after being treated by nitrification reaction, the sewage in which ammonia nitrogen has become nitrate nitrogen and nitrite nitrogen enters the water distribution area 22 for water distribution through the water inlet pipe 6, and then the water enters the upper fluidized bed reaction chamber 8. Under the stirring of the stirring device, it is fully mixed and reacted with the heterotrophic denitrifying biological carrier fillers 10, making full use of the organic substrates and a small amount of externally added carbon source substances in the water. Most of the nitrate nitrogen and nitrite nitrogen in the sewage are reduced to nitrogen gas by heterotrophic bacteria and released outside the water body. At the same time, the stirring device can effectively drive the generated nitrogen gas away from the surface of the carrier, disturb it with the power of stirring, make it destabilize, discharge it from the pool body, and restore the water head. The water head is the smoothness of water. The substances that generate bicarbonate during the reaction increase the alkalinity of the sewage and supplement the alkalinity demand for autotrophic denitrification in the lower fixed bed reaction chamber 12. Then, when the sewage passes through the autotrophic denitrifying filler layer 11 in the lower fixed bed reaction chamber 12, the remaining nitrate nitrogen and nitrite nitrogen continue to be reduced to nitrogen gas by autotrophic bacteria and consume alkalinity, using the alkalinity generated by heterotrophic denitrification in the upper fluidized bed reaction chamber 8 to reduce the dosing cost of alkalinity agents; the sewage suspended solids form a dense filter layer in the autotrophic denitrifying filler layer 11 to intercept the solid suspended solids, colloids and shed biological membranes in the sewage, and then are further filtered in the filtration layer 14 in the filtration area 13 and finally discharged from the outlet water pipe 16 in the lower outlet water area 18; during backwashing, the water inlet pipe 6 and the outlet water pipe 16 are closed, the backwashing outlet water pipe 23 and the backwashing inlet air pipe 17 are opened, gas is introduced to backwash the filtration layer 14, loosen the compacted filtration layer 14, and use the gaps in the filtration layer 14 for uniform air distribution, and then clean the solids intercepted and generated in the autotrophic denitrifying filler layer 11. Then, the backwashing inlet water pipe 15 is opened to conduct simultaneous air intake and water intake, and the air-water combined cleaning further discharges the solids intercepted and generated in the filter media and fillers. Then, the backwashing inlet air pipe 17 is closed, and the backwashing inlet water pipe 15 is continuously used to conduct water backwashing, and the backwashed water and pollutants are discharged from the backwashing outlet water pipe 23.

[0034] Example 2. On the basis of Example 1, the stirring device includes a high-paddle hyperbolic stirring impeller 21 arranged in the middle and lower part of the upper fluidized bed reaction chamber 8. The high-paddle hyperbolic stirring impeller 21 is fixedly connected to a stirring shaft 26, and the stirring shaft 26 is connected to a stirring motor 1. The distance from the bottom of the high-paddle hyperbolic stirring impeller 21 to the autotrophic denitrification packing layer 11 is 0.5 - 1.0 m, which can not only provide a reaction thrust for the stirring of the high-paddle hyperbolic stirring impeller 21 to improve the mixing reaction effect of the upper fluidized bed reaction chamber 8, but also will not disturb the autotrophic denitrification packing layer 11 in the lower fixed bed reaction chamber 12, and effectively drive away the nitrogen generated by denitrification at the same time. The height of the upper fluidized bed reaction chamber 8 is 3 - 5 m, the height of the lower fixed bed reaction chamber 12 is 3 - 4 m, the overall height is 7 - 10 m, and the diameter is about 7 m. It can be made into a steel device or a concrete tank. The rotation speed of the stirring shaft 26 is 20 - 42 rpm. If the rotation speed is too low, the hybrid power is weak and the fluidization effect is poor. If the rotation speed is too high, the power consumption is large, the carrier wear rate is high, and the biofilm is likely to fall off.

[0035] A hydrofoil stirring paddle 9 is fixed on the stirring shaft 26 in the upper part of the upper fluidized bed reaction chamber 8. The top of the reactor box body 4 is of an open type, and a mounting frame 2 is fixed on the top of the reactor box body 4. The stirring motor 1 is fixed on the mounting frame 2. When the high-paddle hyperbolic stirring impeller 21 rotates, on the one hand, it generates a high-speed radial flow along the tangential direction, and on the other hand, the supplementary water flow of the discharged water body flows downward by gravity to generate an axial flow in the vertical direction, so that the water body obtains a large-area, three-dimensional circulation and gentle flow state, achieving the best stirring effect for the mixing, fluidization and biological denitrification of the best three-dimensional composite biological carrier. Due to the height of the upper fluidized bed reaction chamber 8 being 3 - 5 m, the fluidization effect of the heterotrophic denitrification biological carrier packing 10 in the upper layer is poor, and the hydrofoil stirring paddle 9 provides axial and horizontal stirring forces as an effective supplement to the stirring of the high-paddle hyperbolic stirring impeller 21.

[0036] A water distribution ring plate 7 fixed on the inner wall of the reactor box body 4 is arranged in the water distribution area 22. A water distribution weir 24 is fixed in the inner hole of the water distribution ring plate 7. An anti-washing water outlet weir 5 is arranged outside the water distribution weir 24. The water inlet pipe 6 communicates with the water distribution area between the water distribution weir 24 and the anti-washing water outlet weir 5. The anti-washing water outlet pipe 23 is arranged above the water distribution ring plate 7 and communicates with the water outlet area between the anti-washing water outlet weir 5 and the reactor box body 4. There is a height difference between the top of the water distribution weir 24 and the top of the anti-washing water outlet weir 5.

[0037] A screening mesh 3 is fixed to the top of the water distribution weir 24, and a strengthening ring 25 is fixed to the top of the screening mesh 3. The water inlet pipe 6 enters water along the tangential direction of the inner wall of the backwash outlet weir 5. The screening mesh 3 is made of stainless steel 316L, which can effectively prevent corrosion of the gas-liquid interface. The screening mesh 3 uses strip-shaped grid bars with a gap of 0.8 - 1.5 cm between the strip-shaped grid bars, which is used to intercept the heterotrophic denitrification biological carrier filler 10 and prevent the loss of the heterotrophic denitrification biological carrier filler 10 caused by backwashing and the blockage of the backwash outlet pipe 23.

[0038] The heterotrophic denitrification biological carrier filler 10 is a modified hydrophilic group polyurethane sponge, which has a sufficient specific surface area, wear-resistant material, long service life, excellent fluidization effect, can be evenly mixed with sewage under the action of stirring, provides a place for biological reaction for heterotrophic denitrifying bacteria, and maximizes the heterotrophic denitrification reaction. The autotrophic denitrification filler layer 11 is an iron-sulfur composite autotrophic bacteria filler, and the filter layer 14 is a graded cobblestone layer. There are at least two layers in the graded cobblestone layer, and the particle size of the graded cobblestone layer gradually increases from top to bottom, which can ensure sufficient gaps between adjacent cobblestones in the graded cobblestone layer.

[0039] A filter plate 20 is provided at the bottom of the graded cobblestone layer. A plurality of filter holes are evenly provided on the filter plate 20, and a filter head 19 is provided in each filter hole. The lowermost graded cobblestone layer is placed on the filter plate 20, and sulfur autotrophic special filter heads are evenly distributed on the filter plate 20; to achieve uniform water outlet of the system, and to cooperate with the gaps between adjacent cobblestones in the graded cobblestone layer for uniform gas distribution and water distribution during backwashing. During backwashing, the graded cobblestone layer is located below the autotrophic denitrification filler layer 11 and has a relatively heavy self-weight, which can protect the autotrophic denitrification filler layer 11 and prevent it from being washed out by backwash water and backwash gas.

[0040] The filter head 19 includes a diversion pipeline 197 extending into the filter holes. A fixing nut 198 is threadedly installed on the diversion pipeline 197 below the filter plate 20. A pressing cap plate 196 is fixed at the top of the diversion pipeline 197. Above the pressing cap plate 196, there are multiple distribution rings 194 arranged vertically. A water distribution gap 195 is provided between adjacent distribution rings 194. A support rib 193 is fixed in each water distribution gap 195. The upper and lower ends of the support rib 193 are fixed to the upper and lower distribution rings 194. Above the uppermost distribution ring 194, there is an upper pressing cap plate 191. A pressing bolt 192 is provided on the upper pressing cap plate 191. The lower end of the pressing bolt 192 is threadedly installed on the lower pressing cap plate 196. The water distribution gap 195 is about 2 mm. The diversion pipeline 197, fixing nut 198, distribution rings 194, support ribs 193, pressing bolts 192, lower pressing cap plate 196, and upper pressing cap plate 191 are all made of stainless steel. The filter head 19 with this structure enables the water filtered by the graded cobblestone layer to flow through the water distribution gap 195. Large impurities cannot pass through the water distribution gap 195, so it is not easily blocked, the water distribution and air distribution are more uniform, the particle size of the suspended matter passing through is smaller, and it has better strength, strong anti-aging performance, good pressure resistance, is not easily broken, and has a large flow area.

[0041] A graded cobblestone layer is laid on the filter plate 20. By combining the use of iron-sulfur composite autotrophic bacteria filler as the autotrophic bacteria nutrient substrate and filtration filter material, it can effectively prevent the iron-sulfur composite autotrophic bacteria filler and suspended matter from blocking the filter head 19, causing short-circuit flow and uneven water distribution.

[0042] The present invention organically combines autotrophic denitrification and heterotrophic denitrification, fixed bed and fluidized bed, filter pool technology, and full chamber bed technology, making full use of the space of the reactor box 4. It is a full-system denitrification full chamber bed reactor technology that makes full use of the pool volume. The volume utilization rate is high, and the total nitrogen load and volume load are 2-3 times that of the traditional heterotrophic filter and 2-3 times that of the sulfur autotrophic filter.

[0043] The heterotrophic denitrification biological carrier filler 10 is a 20 mm ± 2 mm square three-dimensional composite biological carrier. Of course, it is not limited to the square three-dimensional structure and can also be spherical. The autotrophic denitrification filler layer 11 uses 3 mm - 5 mm spherical sulfur autotrophic denitrification filler, and is combined with a graded cobblestone layer to support the filler, taking into account the dual functions of denitrification and filtration. The filling height of the autotrophic denitrification filler layer 11 is 1.8 m - 2.4 m. The reactor box 4 is provided with multiple observation ports from top to bottom.

[0044] The autotrophic denitrification filler layer 11 adsorbs and aggregates sulfur autotrophic bacteria to carry out autotrophic denitrification biological reactions. Autotrophic denitrification mainly refers to using inorganic substances (S, S 2- , H2, S2O3 2- , Fe, Fe 2+etc.) etc. are used as electron donors for nitrate nitrogen reduction to complete microbial metabolism, and NO3-N in water polluted by nitrate nitrogen is reduced to N2 by using inorganic carbon (CO2, HCO3 - , CO3 2- ) as a carbon source. At the same time, the filler has uniform particle size, dense voids, and large surface area, which can intercept and filter the shed biofilm, colloid, and suspended matter generated during the denitrification process, ensuring the COD, suspended matter, and turbidity of the effluent. When too many pollutants are intercepted by filtration and the filtration rate drops, air and water backwashing are carried out to restore the denitrification and filtration functions of the system.

[0045] The simultaneous use of heterotrophic bacteria and sulfur autotrophic bacteria in the present invention can achieve alkalinity complementarity. Alkalinity is generated during the process of heterotrophic bacteria reducing nitrate nitrogen and nitrite nitrogen to nitrogen gas, while the process of sulfur autotrophic bacteria reducing nitrate nitrogen consumes alkalinity, ensuring the stability of alkalinity and effluent indicators.

[0046] The autotrophic denitrification filler layer 11 in the lower fixed-bed reaction chamber 12 of the reactor box body 4 can be both a biological carrier for autotrophic denitrifying bacteria and a supplier of autotrophic biological nutrients, and at the same time, it is a highly efficient filter material for filtration, with good filtration function, which can effectively reduce the concentration of solid suspended matter and COD in the effluent.

[0047] Adopting the full-chamber bed technology and double-chamber structure can save more than 50% of the civil engineering investment and reduce more than 60% of the equipment investment. The reactor has a simple structure and can be transformed by using the original BAF filter, deep-bed denitrification filter, etc., reducing the equipment investment.

[0048] The system starts up quickly and can be inoculated and domesticated with the sludge from the aerobic tank. The domestication time is short, and it can be put into use and operate at full load in 3 - 5 days. The total nitrogen in the effluent can be adjusted and controlled, and the effluent indicators and removal efficiency of heterotrophic denitrification and autotrophic denitrification can be accurately adjusted according to the effluent requirements. The total nitrogen in the effluent can reach 1 mg / l, meeting the requirements of various sewage discharges and reclaimed water reuse. The system adjustment time is short, the reaction speed is fast, and the system can meet the effluent requirements in 1 - 2 hours of reaction time. The iron-sulfur composite autotrophic bacteria filler used in the lower fixed-bed reaction chamber 12 of the present invention domesticates and propagates autotrophic bacteria without additional carbon source addition, saving carbon source consumption, and can effectively prevent carbon source penetration caused by the addition of carbon source in heterotrophic denitrification, preventing the increase or exceeding of COD.

[0049] The heterotrophic denitrification biological carrier filler 10 and the autotrophic denitrification filler layer 11, the optimal filler dosage ratio by volume is 1:3 - 1:2, and the nitrate nitrogen load is 0.9 - 1.2 kgNO3 - -N / m 3 ·d.

[0050] Inside the water distribution weir 24, there is a support cylinder 27. At the top of the support cylinder 27, a liquid guiding funnel 28 is fixed. The top of the liquid guiding funnel 28 is fixed on the upper inner wall of the water distribution weir 24. The liquid guiding funnel 28 is evenly provided with liquid leakage holes. At the bottom of the support cylinder 27, a conical water distribution plate 30 is fixed. The water distribution plate 30 is evenly provided with water distribution holes. At the bottom of the water distribution plate 30, there is a downward support bending 39. There is a gap between the outer side of the support bending 39 and the inner wall of the reactor box body 4. The setting of this gap can prevent sewage from accumulating. On the outer side of the support bending 39, a support rod 29 is fixed. The other end of the support rod 29 is fixed to the inner wall of the reactor box body 4. The design of the support bending 39 and the support rod 29 can facilitate the fixation of the water distribution plate 30. The diameters of the liquid leakage holes and the water distribution holes are much smaller than the diameter of the autotrophic denitrification filler. The gap between the outer side of the support bending 39 and the inner wall of the reactor box body 4 is much smaller than the size of the heterotrophic denitrification biological carrier filler 10.

[0051] On the water outlet pipe 16, there is an online nitrate nitrogen detector, which is connected to a controller. On the water inlet pipe 6, a mixing pipeline 31 is connected. At the top of the front end of the mixing pipeline 31, a carbon source dosing pipe 33 is fixed. The lower end of the carbon source dosing pipe 33 extends into the middle and lower position of the mixing pipeline 31. On the left side of the carbon source dosing pipe 33, there is a spray nozzle 32. On the mixing pipeline 31 to the left of the spray nozzle 32, a throttling variable diameter pipe 36 is fixed. On the left side of the throttling variable diameter pipe 36, there is a conical dispersion mixing plate 38. The dispersion mixing plate 38 is evenly provided with dispersion holes. The left end outer side of the throttling variable diameter pipe 36 is sleeved with a reinforcing ring plate 37, and the outer side of the reinforcing ring plate 37 is fixed to the mixing pipeline 31. On the water inlet pipe 6 to the right of the mixing pipeline 31 and on the carbon source dosing pipe 33, there are an electric flow regulating valve 34 and a flowmeter 35 respectively. The electric flow regulating valve 34 and the flowmeter 35 are connected to the controller. On the water inlet pipe 6 to the left of the mixing pipeline 31, the backwash water outlet pipe 23, the backwash air inlet pipe 17, the backwash water inlet pipe 15 and the water outlet pipe 16, there are electric valves connected to the controller. The upper end of the carbon source dosing pipe 33 is connected to a delivery pump and a carbon source tank. Here, the carbon source can be methanol or sodium acetate.

[0052] Since heterotrophic bacteria require a carbon source for growth, a carbon source dosing pipe 33 is provided on the mixing pipe 31 of the inlet pipe 6. The electric flow regulating valves 34 and flow meters 35 are provided on both the inlet pipe 6 on the right side of the mixing pipe 31 and the carbon source dosing pipe 33, which can accurately adjust the amount of carbon source transported according to the sewage inflow. And according to the value of the nitrate nitrogen on-line detector on the outlet pipe 16, the amount of carbon source transported and the sewage inflow are automatically adjusted in reverse. When the value of the nitrate nitrogen on-line detector exceeds the normal value, the amount of carbon source transported can be increased and the sewage inflow can be reduced to achieve dynamic adjustment. After the carbon source enters the mixing pipe 31, it will be sprayed in the direction of sewage flow. When the sewage bypasses the carbon source dosing pipe 33, a vortex will be generated, which will initially mix with the carbon source. Then, throttling will occur when passing through the throttling and diameter-changing pipe 36, and the water flow will be in a turbulent state, accelerating the mixing of the carbon source and sewage. Then, the water flow impacts the dispersion and mixing plate 38 for dispersion and mixing. Then, the mixture of sewage and carbon source enters between the water distribution weir 24 and the backwashing effluent weir 5 in the reactor box body 4 from the inlet pipe 6 for water distribution. Then, the liquid overflows from the top of the water distribution weir 24 and falls into the liquid guiding funnel 28. Part of the liquid will flow along the liquid guiding funnel 28 to the middle position for liquid inlet, and the other part passes through the liquid leakage holes and enters the outer area of the support cylinder 27, and then flows onto the water distribution tray 30, evenly distributed on the upper part of the upper fluidized bed reaction chamber 8, facilitating the mixing of the mixture of carbon source and sewage with the heterotrophic denitrification biological carrier filler 10. In addition, since the autotrophic denitrification filler layer 11 will act as a supplier of autotrophic biological nutrients, with the passage of time, the autotrophic denitrification filler layer 11 will be gradually decomposed and digested. Therefore, it needs to be replenished regularly. When replenishing the autotrophic denitrification filler layer 11, it will be put in at the middle position above the interception screen 3. Therefore, when the autotrophic denitrification filler layer 11 falls, it will pass through the support cylinder 27. The setting of the liquid guiding funnel 28 can prevent the autotrophic denitrification filler layer 11 from entering the outer side of the support cylinder 27 and causing retention.

[0053] The above embodiments only represent one or several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A full-bed coupled biological denitrification reactor, comprising a reactor box body (4), characterized in that: Inside the reactor box body (4), there are successively arranged a water distribution area (22), an upper fluidized bed reaction chamber (8), a lower fixed bed reaction chamber (12), a filtration area (13) and an effluent area (18) from top to bottom. The water distribution area (22) is connected with a water inlet pipe (6) and a backwash outlet pipe (23). Inside the upper fluidized bed reaction chamber (8), there is a heterotrophic denitrification biological carrier filler (10) that can be suspended in water. Inside the lower fixed bed reaction chamber (12), there is an autotrophic denitrification filler layer (11). Inside the filtration area (13), there is a filtration layer (14). The effluent area (18) is connected with an effluent pipe (16), a backwash inlet air pipe (17) and a backwash inlet water pipe (15). A stirring device is arranged inside the upper fluidized bed reaction chamber (8); Inside the water distribution area (22), there is a water distribution ring plate (7) fixed on the inner wall of the reactor box body (4). A water distribution weir (24) is fixed in the inner hole of the water distribution ring plate (7). A backwash outlet weir (5) is arranged outside the water distribution weir (24). The water inlet pipe (6) communicates with the water distribution area between the water distribution weir (24) and the backwash outlet weir (5). The backwash outlet pipe (23) is arranged above the water distribution ring plate (7) and communicates with the water outlet area between the backwash outlet weir (5) and the reactor box body (4). There is a height difference between the top of the water distribution weir (24) and the top of the backwash outlet weir (5); Inside the water distribution weir (24), there is a support cylinder (27). At the top of the support cylinder (27), there is a liquid guiding funnel (28) fixed. The top of the liquid guiding funnel (28) is fixed on the upper inner side wall of the water distribution weir (24). The liquid guiding funnel (28) is evenly provided with liquid leakage holes. At the bottom of the support cylinder (27), there is a conical water distribution plate (30) fixed. The water distribution plate (30) is evenly provided with water distribution holes. At the bottom of the water distribution plate (30), there is a downward support bend (39). There is a gap between the outer side of the support bend (39) and the inner wall of the reactor box body (4). On the outer side of the support bend (39), there is a support rod (29) fixed. The other end of the support rod (29) is fixed to the inner wall of the reactor box body (4).

2. The full-bed coupled biological denitrification reactor according to claim 1, wherein The stirring device includes a high-paddle hyperbolic stirring impeller (21) arranged in the middle and lower part of the upper fluidized bed reaction chamber (8). The high-paddle hyperbolic stirring impeller (21) is fixedly connected with a stirring shaft (26). The stirring shaft (26) is connected with a stirring motor (1). The distance from the bottom of the high-paddle hyperbolic stirring impeller (21) to the autotrophic denitrification filler layer (11) is 0.5 - 1.0 m.

3. The full-bed coupled biological denitrification reactor according to claim 2, characterized in that, On the stirring shaft (26) in the upper part of the upper fluidized bed reaction chamber (8), there is a hydrofoil stirring paddle (9) fixed. The top of the reactor box body (4) is of an open type. An installation frame (2) is fixed on the top of the reactor box body (4). The stirring motor (1) is fixed on the installation frame (2).

4. The full-bed coupling biological denitrification reactor according to claim 1, characterized in that, On the top of the water distribution weir (24), there is an intercepting screen (3) fixed. On the top of the intercepting screen (3), there is a reinforcing ring (25) fixed. The water inlet pipe (6) enters water along the tangent direction of the inner wall of the backwash outlet weir (5).

5. The full-bed coupled biological denitrification reactor according to claim 1, wherein, The heterotrophic denitrification biological carrier filler (10) is a modified hydrophilic polyurethane sponge, the autotrophic denitrification filler layer (11) is an iron-sulfur composite autotrophic bacteria filler, and the filter layer (14) is a graded cobblestone layer. There are at least two graded cobblestone layers, and the particle size of the graded cobblestone layer gradually increases from top to bottom.

6. The full-bed coupled biological denitrification reactor according to claim 5, characterized in that, A filter plate (20) is provided at the bottom of the graded cobblestone layer. A plurality of filter holes are evenly provided on the filter plate (20), and a filter head (19) is provided in each filter hole.

7. The full-bed coupled biological denitrification reactor according to claim 1, characterized in that, A nitrate nitrogen on-line detector is provided on the water outlet pipe (16). The nitrate nitrogen on-line detector is connected to a controller. A mixing pipe (31) is connected to the water inlet pipe (6). A carbon source dosing pipe (33) is fixed to the top of the front end of the mixing pipe (31). The lower end of the carbon source dosing pipe (33) extends to a position slightly below the middle of the mixing pipe (31). A spray nozzle (32) is provided on the left side of the carbon source dosing pipe (33). A throttle reducing pipe (36) is fixed to the mixing pipe (31) on the left side of the spray nozzle (32). A conical dispersion mixing plate (38) is provided on the left side of the throttle reducing pipe (36). A plurality of dispersion holes are evenly provided on the dispersion mixing plate (38). A reinforcing ring plate (37) is sleeved on the outer side of the left end of the throttle reducing pipe (36). The outer side of the reinforcing ring plate (37) is fixed to the mixing pipe (31). Electric flow regulating valves (34) and flow meters (35) are provided on both the water inlet pipe (6) on the right side of the mixing pipe (31) and the carbon source dosing pipe (33). The electric flow regulating valves (34) and the flow meters (35) are connected to the controller.

8. The full-bed coupled biological denitrification reactor according to claim 6, characterized in that, The filter head (19) includes a diversion pipe (197) extending into the filter hole. A fixing nut (198) is threadedly installed on the diversion pipe (197) below the filter plate (20). A pressing cap plate (196) is fixed to the top of the diversion pipe (197). A plurality of distribution rings (194) arranged vertically are provided above the pressing cap plate (196). A water distribution gap (195) is provided between adjacent distribution rings (194). A support rib (193) is fixed in each water distribution gap (195). The upper and lower ends of the support rib (193) are fixed to the upper and lower distribution rings (194). An upper pressing cap plate (191) is provided above the uppermost distribution ring (194). A pressing bolt (192) is provided on the upper pressing cap plate (191). The lower end of the pressing bolt (192) is threadedly installed on the pressing cap plate (196).

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