Integrated nitrogen and phosphorus removal bioreactor and process thereof

Abstract

The invention relates to the technical field of sewage treatment, and discloses an integrated nitrogen and phosphorus removal bioreactor and a process thereof, the integrated nitrogen and phosphorus removal bioreactor comprises an anaerobic tank, a denitrification tank, a short-cut nitrification tank, an anaerobic ammonia oxidation tank, an aeration tank, a sedimentation tank, a concentration tank and a phosphorus recovery device, the denitrification tank is arranged on one side of the anaerobic tank and is communicated with the anaerobic tank through a first through-wall water passing hole, the short-cut nitrification tank is arranged on one side of the denitrification tank and is communicated with the denitrification tank through a second through-wall water passing hole, and the anaerobic ammonia oxidation tank is arranged on one side of the short-cut nitrification tank and is communicated with the denitrification tank through a second through-wall water passing hole. And the anaerobic ammonia oxidation tank is communicated with the short-cut nitrification tank through a third through-wall water passing hole. The anaerobic tank and the denitrification tank are arranged at the front end, so that most organic matters in the sewage can be removed in advance while a carbon source in the sewage is fully utilized for denitrification and dephosphorization, and subsequent short-cut nitrification and screening culture of anaerobic ammonia oxidation strains are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and specifically to an integrated nitrogen and phosphorus removal bioreactor and its process. Background Art

[0002] In recent years, the excessive discharge of nitrogen and phosphorus-containing wastewater has caused a series of ecological and environmental problems such as water eutrophication. The efficient and low-consumption treatment of ammonia nitrogen and phosphate-containing wastewater has always been a difficult problem in the field of sewage treatment. Facing wastewater with a low C:N:P ratio, traditional nitrification-denitrification processes and anaerobic-aerobic biological phosphorus removal technologies can no longer meet the current sewage treatment efficiency.

[0003] Sewage with an imbalanced carbon-nitrogen ratio has always been a major difficulty in the sewage treatment industry, such as municipal sewage, pharmaceutical wastewater, food wastewater, breeding and slaughter wastewater, etc. The prominent problem in the treatment of such wastewater is nitrogen and phosphorus removal. Currently, the A2 / O biological nitrogen and phosphorus removal process is commonly used at home and abroad, but it has problems such as large floor area, high energy consumption, and high operating costs. With the increasingly stringent discharge standards and the national requirement of carbon neutrality, it is difficult for traditional processes to achieve efficient and energy-saving deep nitrogen and phosphorus removal. Therefore, it is necessary to develop an energy-saving and efficient nitrogen and phosphorus removal process. Short-cut nitrification-denitrification technology, anaerobic ammonium oxidation technology, etc. can achieve efficient nitrogen and phosphorus removal with only a small amount of carbon source or without a carbon source, reducing the consumption of carbon source and energy, and thus becoming the current research hotspot. However, the engineering application is less. The difficulty is how to effectively screen the dominant strains in each reaction process and ensure the stable operation of the system reaction to improve the treatment efficiency. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the present invention provides an integrated nitrogen and phosphorus removal bioreactor and its process, aiming to improve the problems of large floor area, high energy consumption, and low nitrogen and phosphorus removal effect in the existing device.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: an integrated denitrification and phosphorus removal bioreactor, comprising an anaerobic tank, a denitrification tank, a shortcut nitrification tank, an anaerobic ammonium oxidation tank, an aeration tank, a sedimentation tank, a thickening tank, and a phosphorus recovery device. The denitrification tank is arranged on one side of the anaerobic tank, and the denitrification tank and the anaerobic tank are connected through a first through-wall water passage hole. The shortcut nitrification tank is arranged on one side of the denitrification tank, and the shortcut nitrification tank and the denitrification tank are connected through a second through-wall water passage hole. The anaerobic ammonium oxidation tank is arranged on one side of the shortcut nitrification tank, and the anaerobic ammonium oxidation tank and the shortcut nitrification tank are connected through a third through-wall water passage hole. The aeration tank is arranged on one side of the anaerobic ammonium oxidation tank, and the aeration tank and the anaerobic ammonium oxidation tank are connected through a fourth through-wall water passage hole. The sedimentation tank is arranged on one side of the aeration tank, and an overflow wall is provided between the sedimentation tank and the aeration tank. The thickening tank is arranged on one side of the sedimentation tank, and a sludge discharge pipe is connected to one side of the thickening tank. A first raw water inlet pipe is connected to one side of the anaerobic tank.

[0006] Through the above technical solutions: wastewater first enters the anaerobic tank, where polyphosphate-accumulating organisms absorb and convert organic matter in the sewage into intracellular polymers under anaerobic conditions, and at the same time degrade and release a large amount of phosphate into the water. Then it enters the denitrification tank, where a denitrification reaction occurs, and denitrifying bacteria reduce nitrate nitrogen and nitrite nitrogen in the wastewater to nitrogen gas. Then it enters the shortcut nitrification tank, where a shortcut nitrification reaction occurs, oxidizing part of the ammonia nitrogen in the wastewater to nitrite nitrogen. Subsequently, it enters the anaerobic ammonium oxidation tank for autotrophic denitrification. Then it enters the aeration tank, where polyphosphate-accumulating organisms aerobically decompose the stored intracellular polymers to generate energy, absorb excessive phosphate in the sewage, and at the same time aerobic bacteria degrade the residual organic matter and ammonia nitrogen in the sewage, and remove the residual gas in the sewage to facilitate subsequent sedimentation. The effluent from the aeration tank finally enters the sedimentation tank for sedimentation separation. The sedimented sludge is thickened in the thickening tank, and the sludge is discharged externally. The supernatant is treated by the phosphorus recovery device and then discharged into the denitrification tank.

[0007] Preferably, a first agitator is provided inside the anaerobic tank, and a through-wall axial flow pump is provided between the anaerobic tank and the thickening tank.

[0008] Preferably, a second agitator is provided inside the denitrification tank. A phosphorus recovery drain pipe is connected to one side of the denitrification tank, and one end of the phosphorus recovery drain pipe is connected to the phosphorus recovery device. An on-line ORP meter is provided in the denitrification tank.

[0009] Preferably, a reflux pump is provided inside the short-cut nitrification tank. One side of the reflux pump is connected to a reflux inlet water pipe, and one end of the reflux inlet water pipe communicates with the inside of the denitrification tank. A blower is provided on one side of the short-cut nitrification tank. An on-line pH meter, a dissolved oxygen meter, an on-line ammonia nitrogen detector and an alkali dosing device are provided outside the short-cut nitrification tank. A first biological filler is provided inside the short-cut nitrification tank, and a low dissolved oxygen aeration system is provided at the inner bottom of the short-cut nitrification tank.

[0010] Preferably, a third agitator is provided inside the anaerobic ammonium oxidation tank. A draft tube is provided outside the third agitator. A second biological filler is provided inside the anaerobic ammonium oxidation tank. One side of the anaerobic ammonium oxidation tank is connected to a second raw water inlet pipe, and the second raw water inlet pipe is connected to the first raw water inlet pipe. An on-line nitrite nitrogen detector and an on-line ammonia nitrogen detector are installed outside the anaerobic ammonium oxidation tank. An aeration system is provided inside the aeration tank, and an overflow wall is installed inside the aeration tank.

[0011] Preferably, a sedimentation water distribution and degassing tank is provided inside the sedimentation tank. Inclined tube fillers are provided inside the sedimentation tank. A mud hopper is provided at the inner bottom of the sedimentation tank. Water passing holes are formed in the inner wall of the sedimentation tank. An outlet pipe is connected to one side of the sedimentation tank. A reflux tank is provided inside the sedimentation tank. A water distribution tank is provided inside the thickening tank. A sludge discharge pipe is connected to one side of the thickening tank. A drain pipe is connected to the outer surface of the thickening tank, and one end of the drain pipe is connected to a phosphorus recovery device.

[0012] A process of an integrated nitrogen and phosphorus removal bioreactor includes the following steps:

[0013] In the first stage, the raw water inlet is divided into two paths. One path of raw water is mixed with the reflux sludge and then enters the anaerobic tank, where anaerobic phosphorus release reaction occurs. Subsequently, it is mixed with the drainage of the phosphorus recovery device and the reflux nitrification liquid of the short-cut nitrification tank and enters the denitrification tank together.

[0014] In the second stage, after being treated in the denitrification tank, it enters the short-cut nitrification tank for short-cut nitrification reaction to oxidize ammonia nitrogen into nitrite nitrogen. A part of the mixed liquid in the short-cut nitrification tank is refluxed to the denitrification tank to supplement nitrite in the denitrification tank.

[0015] In the third stage, the sewage after the reaction in the short-cut nitrification tank is mixed with the other path of raw water and enters the anaerobic ammonium oxidation tank. The anaerobic ammonium oxidizing bacteria use nitrite as an electron acceptor to oxidize ammonia nitrogen into nitrogen gas, and then enter the aeration tank for aerobic phosphorus uptake, organic matter degradation, nitrification and nitrogen stripping.

[0016] In the fourth stage, it finally enters the sedimentation tank for mud-water separation. The sedimented sludge is then refluxed to the thickening tank and the anaerobic tank. The thickened sludge at the bottom after thickening in the thickening tank is discharged as excess sludge, and the supernatant is discharged into the phosphorus recovery device for phosphorus recovery. The sewage after phosphorus recovery is discharged into the denitrification tank.

[0017] Preferably, the reaction tanks in the reactor form a closed-loop circuit according to the technological process, and each tank is arranged in a ring shape. The connecting pipelines are short and the head loss is small.

[0018] Preferably, the supernatant of the thickening tank is refluxed to the denitrification tank after being treated by the phosphorus recovery device, and there is a mixed liquid reflux from the shortcut nitrification tank to the denitrification tank.

[0019] Preferably, the shortcut nitrification tank adopts low-dissolved oxygen aeration, and there is an internal reflux from the reflux tank to the shortcut nitrification tank. Packing is arranged in the shortcut nitrification tank and the anaerobic ammonium oxidation tank, and the volume ratio of the packing is ≤60%.

[0020] Working principle: The raw water is mixed with the refluxed sludge and then enters the anaerobic tank, where anaerobic phosphorus release reaction occurs. Subsequently, it enters the denitrification tank together with the supernatant of the thickening tank after phosphorus removal by the phosphorus recovery device and the refluxed nitrified liquid of the shortcut nitrification tank for mud-water mixing. After being treated by the denitrification tank, it enters the shortcut nitrification tank for shortcut nitrification reaction to oxidize ammonia nitrogen to nitrite nitrogen. Part of the mixed liquid in the shortcut nitrification tank is refluxed to the denitrification tank to supplement nitrite in the denitrification tank.

[0021] The sewage after the reaction in the shortcut nitrification tank is mixed with another path of raw water and enters the anaerobic ammonium oxidation tank. The anaerobic ammonium oxidation bacteria use nitrite as an electron acceptor to oxidize ammonia nitrogen to nitrogen gas, and then enter the aeration tank for aerobic phosphorus uptake, organic matter degradation, nitrification and nitrogen stripping. Finally, it enters the sedimentation tank for mud-water separation, and the sedimented sludge is refluxed to the thickening tank and the anaerobic tank. The thickened sludge at the bottom after thickening in the thickening tank is discharged, and the supernatant is discharged into the phosphorus recovery device for phosphorus recovery, and the drained water after recovery is discharged into the denitrification tank.

[0022] The present invention provides an integrated nitrogen and phosphorus removal biological reactor and its process. It has the following beneficial effects:

[0023] 1. By setting an anaerobic tank and a denitrification tank at the front end, the present invention can not only make full use of the carbon source in the sewage for nitrogen and phosphorus removal, but also pre-remove most of the organic matter in the sewage, which is beneficial to the screening and cultivation of subsequent shortcut nitrification and anaerobic ammonium oxidation bacteria.

[0024] 2. The present invention adds a thickening tank to increase the concentration of the discharged sludge, reduce the sludge flow rate, and at the same time, the phosphorus in the supernatant can be recovered after anaerobic phosphorus release. Moreover, each reaction section is arranged in a different tank body, and each reaction section can be independently controlled to ensure that each reaction section plays the best efficiency.

[0025] 3. After anaerobic ammonium oxidation, partial reflux of the residual nitrate in the effluent can strengthen the denitrification effect, improve the overall denitrification efficiency. Biological fillers are set in the shortcut nitrification tank and the anaerobic ammonium oxidation tank, which ensures the quantity of ammonia-oxidizing bacteria and anaerobic ammonium-oxidizing bacteria and improves the treatment efficiency. By adjusting the internal reflux ratio of the shortcut nitrification, the ammonia nitrogen and nitrite concentrations in the shortcut nitrification tank can be flexibly controlled, ensuring the stable operation of the shortcut nitrification.

[0026] 4. The whole system of the present invention has a compact structure, occupies a small area, has fewer connecting pipelines, is convenient to operate, has a relatively long sludge retention time of the system, and has a low sludge yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the internal floor plan of the present invention;

[0028] Figure 2 is the schematic sectional plan view of the present invention;

[0029] Figure 3 is the schematic process flow diagram of the present invention.

[0030] Among them, 1. Anaerobic tank; 1.1. First raw water inlet pipe; 1.2. First agitator; 1.3. First through-wall water passing hole; 1.4. Through-wall axial flow pump; 2. Denitrification tank; 2.1. Second agitator; 2.2. Return inlet pipe; 2.3. Phosphorus recovery drain pipe; 2.4. Second through-wall water passing hole; 2.5. Online ORP meter; 3. Shortcut nitrification tank; 3.1. Return pump; 3.2. Blower; 3.3. Low dissolved oxygen aeration system; 3.4. First biological filler; 3.5. Online pH meter; 3.6. Dissolved oxygen meter; 3.7. Online ammonia nitrogen detector; 3.8. Alkali dosing device; 3.9. Third through-wall water passing hole; 4. Anaerobic ammonium oxidation tank; 4.1; Third agitator; 4.2. Draft tube; 4.3. Second biological filler; 4.4. Second raw water inlet pipe; 4.5. Fourth through-wall water passing hole; 4.6. Online nitrite nitrogen detector; 4.7. Online ammonia nitrogen detector; 5. Aeration tank; 5.1. Aeration system; 5.2. Overflow wall; 6. Sedimentation tank; 6.1. Sedimentation water distribution and degassing tank; 6.2. Inclined tube filler; 6.3; Mud hopper; 6.4. Water passing hole; 6.5. Outlet pipe; 6.6. Return tank; 7. Thickening tank; 7.1. Water distribution tank; 7.2. Sludge discharge pipe; 7.3. Drain pipe; 8. Phosphorus recovery device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0032] Example:

[0033] Please refer to the attached Figure 1 - attached Figure 3 , the embodiment of the present invention provides an integrated denitrification and phosphorus removal bioreactor and its process, including an anaerobic tank 1, a denitrification tank 2, a shortcut nitrification tank 3, an anaerobic ammonium oxidation tank 4, an aeration tank 5, a sedimentation tank 6, a thickening tank 7, and a phosphorus recovery device 8. The denitrification tank 2 is arranged on one side of the anaerobic tank 1, and the denitrification tank 2 and the anaerobic tank 1 are connected through a first through-wall water hole 1.3. The shortcut nitrification tank 3 is arranged on one side of the denitrification tank 2, and the shortcut nitrification tank 3 and the denitrification tank 2 are connected through a second through-wall water hole 2.4. The anaerobic ammonium oxidation tank 4 is arranged on one side of the shortcut nitrification tank 3, and the anaerobic ammonium oxidation tank 4 and the shortcut nitrification tank 3 are connected through a third through-wall water hole 3.9. The aeration tank 5 is arranged on one side of the anaerobic ammonium oxidation tank 4, and the aeration tank 5 and the anaerobic ammonium oxidation tank 4 are connected through a fourth through-wall water hole 4.5. The sedimentation tank 6 is arranged on one side of the aeration tank 5, and an overflow wall 5.2 is provided between the sedimentation tank 6 and the aeration tank 5. The thickening tank 7 is arranged on one side of the sedimentation tank 6, and a sludge discharge pipe 7.2 is connected to one side of the thickening tank 7. One side of the anaerobic tank 1 is connected with a first raw water inlet pipe 1.1.

[0034] Specifically, the raw water can enter the inside of the anaerobic tank 1 through the first raw water inlet pipe 1.1. The anaerobic tank 1, the denitrification tank 2, the shortcut nitrification tank 3, and the anaerobic ammonium oxidation tank 4 are all connected in sequence through the through-wall water holes, so as to ensure the transportation of the raw water. The raw water first enters the inside of the anaerobic tank, and through the metabolic action of anaerobic microorganisms, the organic matter in the sewage is decomposed and transformed. At the same time, the polyphosphate-accumulating organisms decompose the polyphosphate stored in their bodies under anaerobic conditions, and use the energy generated by the decomposition to absorb the organic matter in the wastewater, while the inorganic phosphorus generated by the decomposition of polyphosphate is released back into the sewage, so as to preliminarily treat the raw water. The treated raw water will enter the inside of the denitrification tank 2, and the denitrifying bacteria inside the denitrification tank 2 are used to reduce nitrate nitrogen and nitrite nitrogen to nitrogen gas under anoxic conditions, so as to achieve the purpose of nitrogen and organic matter removal, and further treat the raw water. After treatment, the raw water will enter the inside of the anaerobic ammonium oxidation tank 4 through the shortcut nitrification tank 3. Inside the anaerobic ammonium oxidation tank 4, under the action of anaerobic ammonium oxidation bacteria, ammonia nitrogen and nitrite nitrogen in the water are converted into nitrogen gas and nitrate nitrogen, so as to further treat the raw water.

[0035] Please refer to the attached Figure 1 - attached Figure 3 , a first stirrer 1.2 is provided inside the anaerobic tank 1, and a through-wall axial flow pump 1.4 is provided between the anaerobic tank 1 and the thickening tank 7.

[0036] Specifically, the first mixer 1.2 operates in the anaerobic tank to ensure sufficient mixing of sewage and microorganisms, creating favorable conditions for anaerobic reactions. The precipitated sludge inside the sedimentation tank 6 can be pumped into the anaerobic tank 1 through the wall-piercing axial flow pump 1.4 to supplement the activated sludge in the anaerobic tank.

[0037] Please refer to the attached Figure 1 - attached Figure 3 , a second mixer 2.1 is provided inside the denitrification tank 2. One side of the denitrification tank 2 is connected to a phosphorus recovery drain pipe 2.3, and one end of the phosphorus recovery drain pipe 2.3 is connected to the phosphorus recovery device 8. An on-line ORP meter 2.5 is provided outside the denitrification tank 2.

[0038] Specifically, the second mixer 2.1 operates in the denitrification tank to ensure sufficient mixing of sewage and microorganisms, promoting the denitrification reaction. The reflux inlet pipe 2.2 allows some of the treated sewage to flow back into the denitrification tank through the reflux inlet pipe, providing nitrate nitrogen and nitrite nitrogen for the denitrification reaction. The phosphorus recovery drain pipe 2.3 discharges the treated water after passing through the phosphorus recovery device 8 into the denitrification tank to further treat the remaining phosphorus therein.

[0039] Please refer to the attached Figure 1 - attached Figure 3 , a reflux pump 3.1 is provided inside the short-cut nitrification tank 3. One side of the reflux pump 3.1 is connected to a reflux inlet pipe 2.2, and one end of the reflux inlet pipe 2.2 is communicated with the inside of the denitrification tank 2. A blower 3.2 is provided on one side of the short-cut nitrification tank 3. An on-line pH meter 3.5, a dissolved oxygen meter 3.6, an on-line ammonia nitrogen detector 3.7 and an alkali dosing device 3.8 are provided outside the short-cut nitrification tank 3. A first biological filler 3.4 is provided inside the short-cut nitrification tank 3, and a low dissolved oxygen aeration system 3.3 is provided at the inner bottom of the short-cut nitrification tank 3.

[0040] Specifically, the reflux pump 3.1 returns part of the nitrified liquid to the denitrification tank to provide the nitrate nitrogen and nitrite nitrogen required for denitrification. The blower 3.2 provides oxygen for the short-cut nitrification tank, which is evenly distributed into the tank through the low dissolved oxygen aeration system 3.3 to promote the nitrification reaction. The first biological filler 3.4 provides an attachment surface for microorganisms, increasing the amount of microorganisms and improving the nitrification efficiency. These on-line monitoring instruments such as the on-line pH meter 3.5, the dissolved oxygen meter 3.6 and the on-line ammonia nitrogen detector 3.7 are respectively used to monitor the pH value, the dissolved oxygen content and the ammonia nitrogen concentration in the tank to ensure the stability and optimization of the nitrification reaction conditions. The alkali dosing device 3.8 automatically adjusts the pH value according to the monitoring results of the on-line pH meter 3.5 to maintain the optimal nitrification reaction conditions.

[0041] Please refer to the attached Figure 1 - attached Figure 3, a third agitator 4.1 is provided inside the anammox tank 4, a draft tube 4.2 is provided outside the third agitator 4.1, a second biological packing 4.3 is provided inside the anammox tank 4, a second raw water inlet pipe 4.4 is connected to one side of the anammox tank 4, and the second raw water inlet pipe 4.4 is connected to the first raw water inlet pipe 1.1. An on-line nitrite nitrogen detector 4.6 and an on-line ammonia nitrogen detector 4.7 are installed outside the anammox tank 4. An aeration system 5.1 is provided inside the aeration tank 5, and an overflow wall 5.2 is installed inside the aeration tank 5.

[0042] Specifically, the third agitator 4.1 operates in the anammox tank to ensure full mixing of the sewage and microorganisms, promoting the anammox reaction. A draft tube 4.2 is provided on the third agitator 4.1 to achieve circulating agitation in the anaerobic tank and improve the treatment efficiency. The second biological packing 4.3 provides an attachment surface for microorganisms, increasing the amount of microorganisms and improving the anammox efficiency. The on-line nitrite nitrogen detector 4.6 and the on-line ammonia nitrogen detector 4.7 are used to monitor the nitrite nitrogen and ammonia nitrogen concentrations in the tank respectively to ensure the stability and optimization of the anammox reaction conditions. The aeration system 5.1 aerates the water body through aeration to maintain an aerobic state, and at the same time promotes the escape of gases (such as nitrogen) in the sewage to remove the gases in the sewage. The overflow wall 5.2 ensures that the treated sewage can flow out of the aeration tank smoothly and enter the next treatment unit.

[0043] Please refer to the appendix Figure 1 - appendix Figure 3 , a sedimentation and water distribution degassing tank 6.1 is provided inside the sedimentation tank 6, inclined tube packing 6.2 is provided inside the sedimentation tank 6, a sludge hopper 6.3 is provided at the inner bottom of the sedimentation tank 6, water passing holes 6.4 are formed in the inner wall of the sedimentation tank 6, a water outlet pipe 6.5 is connected to one side of the sedimentation tank 6, and a reflux tank 6.6 is provided inside the sedimentation tank 6. A water distribution tank 7.1 is provided inside the thickening tank 7, a sludge discharge pipe 7.2 is connected to one side of the thickening tank 7, and a drain pipe 7.3 is connected to the outer surface of the thickening tank 7, and one end of the drain pipe 7.3 is connected to the phosphorus recovery device 8.

[0044] Specifically, the precipitation water distribution degassing tank 6.1 helps to optimize the precipitation process and improve the precipitation efficiency. The inclined tube packing 6.2 increases the precipitation area and improves the precipitation rate. The mud hopper 6.3 is used to collect the precipitated sludge and discharge it regularly. The water passing holes 6.4 discharge the precipitated sludge into the reflux tank 6.6. The water outlet pipe 6.5 discharges the treated clear water out of the system. Part of the precipitated sludge in the reflux tank 6.6 is refluxed to the front end of the system through the reflux tank to supplement the activated sludge volume of the system. The water distribution tank 7.1 is used for the distribution and rectification of the influent water. The sludge discharge pipe 7.2 discharges the concentrated sludge out of the system. The drain pipe 7.3 discharges the supernatant in the thickening tank. The sludge concentration in the anaerobic tank 1, denitrification tank 2, shortcut nitrification tank 3, anammox tank 4, and aeration tank 5 is 4000 - 6000 mg / L.

[0045] A process for an integrated nitrogen and phosphorus removal bioreactor includes the following steps:

[0046] In the first stage, the raw water inlet is divided into two paths. One path of the raw water is mixed with the reflux sludge and then enters the anaerobic tank 1, where an anaerobic phosphorus release reaction occurs. Subsequently, it is mixed with the drainage of the phosphorus recovery device 8 and the reflux nitrified liquid of the shortcut nitrification tank 3 and enters the denitrification tank 2 together.

[0047] In the second stage, after being treated in the denitrification tank 2, it enters the shortcut nitrification tank 3 for a shortcut nitrification reaction to oxidize ammonia nitrogen to nitrite nitrogen. Part of the mixed liquid in the shortcut nitrification tank 3 is refluxed to the denitrification tank 2 to supplement nitrite in the denitrification tank 2.

[0048] In the third stage, the sewage after the reaction in the shortcut nitrification tank 3 is mixed with the other path of raw water and enters the anammox tank 4. The anammox bacteria use nitrite as an electron acceptor to oxidize ammonia nitrogen to nitrogen gas, and then enter the aeration tank 5 for aerobic phosphorus uptake, organic matter degradation, nitrification, and nitrogen stripping.

[0049] In the fourth stage, finally, it enters the sedimentation tank 6 for sedimentation separation. The precipitated sludge is refluxed to the thickening tank 7 and the anaerobic tank 1. The concentrated sludge at the bottom of the thickening tank 7 after concentration is discharged as excess sludge, and the supernatant is discharged into the phosphorus recovery device 8 for phosphorus recovery. The sewage after phosphorus recovery is discharged into the denitrification tank 2.

[0050] Specifically, the first raw water inlet pipe and the second raw water inlet pipe are connected. Thus, when raw water enters the first raw water inlet pipe, it can successively enter the anaerobic tank 1 and the anammox tank 4. For the raw water entering the anaerobic tank 1, the microorganisms in the anaerobic tank can decompose and transform the organic matter in the raw water through their metabolic activities. Meanwhile, the phosphorus-accumulating bacteria release phosphorus. After preliminary treatment, the raw water enters the denitrification tank 2, where the denitrifying bacteria in the denitrification tank 2 reduce nitrate nitrogen and nitrite nitrogen to nitrogen gas under anoxic conditions, thereby achieving the purpose of nitrogen and organic matter removal. After treatment, the raw water enters the shortcut nitrification tank 3, where the ammonia nitrogen in the raw water is oxidized to nitrite nitrogen. Meanwhile, a part of the mixed liquor in the shortcut nitrification tank 3 is refluxed to the denitrification tank 2 to supplement nitrite in the denitrification tank. Subsequently, the raw water enters the anammox tank 4, where the anammox bacteria in the anammox tank 4 use nitrite as an electron acceptor to directly oxidize ammonia nitrogen to nitrogen gas. Then it enters the aeration tank 5 for oxygenation and aeration, where the phosphorus-accumulating bacteria complete the phosphorus uptake reaction. Meanwhile, aerobic bacteria degrade the residual organic matter and ammonia nitrogen in the sewage, and in addition, the residual gas in the sewage is removed by aeration to facilitate subsequent sedimentation. Finally, it enters the sedimentation tank 6 for sedimentation to separate the sludge from the water.

[0051] Please refer to the attached Figure 1 - attached Figure 3 , between the first stage and the fourth stage, it also includes: the reaction tanks in the reactor form a closed-loop circuit according to the technological process, each tank is arranged in a ring shape, the connecting pipelines are short, and the head loss is small.

[0052] Specifically, a closed-loop circuit is formed among the anaerobic tank 1, the denitrification tank 2, the shortcut nitrification tank 3, the anammox tank 4, the aeration tank 5, the sedimentation tank 6, and the thickening tank 7. The closed-loop circuit can make the sewage circulate multiple times in the treatment tanks, extend the residence time of the sewage in the treatment system, and allow the sewage to fully contact and react with microorganisms, etc., so as to more effectively remove pollutants and improve the sewage treatment effect. For example, in the activated sludge process treatment system, the circulating reflux can make the sludge and sewage fully mixed, improving the degradation efficiency of organic matter.

[0053] Please refer to the attached Figure 1 - attached Figure 3 , in the fourth stage, it also includes: the supernatant of the thickening tank 7 is treated by the phosphorus recovery device 8 and then refluxed to the denitrification tank 2, and there is a mixed liquor reflux from the shortcut nitrification tank 3 to the denitrification tank 2.

[0054] Please refer to the attached Figure 1 - attached Figure 3 , in the third stage, it also includes: the shortcut nitrification tank 3 uses low-dissolved oxygen aeration, and fillers are arranged in the shortcut nitrification tank 3 and the anammox tank 4, and the volume ratio of the fillers is ≤ 60%.

[0055] Specifically, the packing provides a large amount of attachment surfaces for microorganisms such as nitrifying bacteria and anaerobic ammonia-oxidizing bacteria, enabling the microorganisms to grow, reproduce and form biofilms on its surface. In this way, the short-cut nitrification tank 3 and the anaerobic ammonia oxidation tank can increase the quantity and concentration of microorganisms, improve the reaction efficiency, and the packing provides a stable habitat for the microorganisms, enabling them to maintain good activity in an anaerobic environment.

[0056] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An integrated biological reactor for nitrogen and phosphorus removal, comprising an anaerobic tank (1), a denitrification tank (2), a shortcut nitrification tank (3), an anaerobic ammonium oxidation tank (4), an aeration tank (5), a sedimentation tank (6), a thickening tank (7), and a phosphorus recovery device (8), characterized in that: The denitrification tank (2) is arranged on one side of the anaerobic tank (1), and the denitrification tank (2) and the anaerobic tank (1) are connected through a first through-wall water hole (1.3). The shortcut nitrification tank (3) is arranged on one side of the denitrification tank (2), and the shortcut nitrification tank (3) and the denitrification tank (2) are connected through a second through-wall water hole (2.4). The anammox tank (4) is arranged on one side of the shortcut nitrification tank (3), and the anammox tank (4) and the shortcut nitrification tank (3) are connected through a third through-wall water hole (3.9). The aeration tank (5) is arranged on one side of the anammox tank (4), and the aeration tank (5) and the anammox tank (4) are connected through a fourth through-wall water hole (4.5). The sedimentation tank (6) is arranged on one side of the aeration tank (5), and an overflow wall (5.2) is provided between the sedimentation tank (6) and the aeration tank (5). The thickening tank (7) is arranged on one side of the sedimentation tank (6), and a sludge discharge pipe (7.2) is connected to one side of the thickening tank (7). One side of the anaerobic tank (1) is connected with a first raw water inlet pipe (1.1).

2. The integrated denitrification and phosphorus removal bioreactor according to claim 1, wherein: A first mixer (1.2) is arranged inside the anaerobic tank (1), and a through-wall axial flow pump (1.4) is arranged between the anaerobic tank (1) and the thickening tank (7).

3. The integrated denitrification and phosphorus removal bioreactor according to claim 1, wherein: A second mixer (2.1) is arranged inside the denitrification tank (2). One side of the denitrification tank (2) is connected with a phosphorus recovery drain pipe (2.3), and one end of the phosphorus recovery drain pipe (2.3) is connected with a phosphorus recovery device (8). The denitrification tank (2) is provided with an on-line ORP meter (2.5).

4. An integrated denitrification and phosphorus removal bioreactor according to claim 1, characterized in that: A reflux pump (3.1) is arranged inside the shortcut nitrification tank (3). One side of the reflux pump (3.1) is connected with a reflux inlet pipe (2.2), and one end of the reflux inlet pipe (2.2) is communicated with the inside of the denitrification tank (2). A blower (3.2) is arranged on one side of the shortcut nitrification tank (3). An on-line pH meter (3.5), a dissolved oxygen meter (3.6), an on-line ammonia nitrogen detector (3.7) and an alkali dosing device (3.8) are arranged outside the shortcut nitrification tank (3). A first biological filler (3.4) is arranged inside the shortcut nitrification tank (3), and a low dissolved oxygen aeration system (3.3) is arranged at the inner bottom of the shortcut nitrification tank (3).

5. An integrated denitrification and phosphorus removal bioreactor according to claim 1, characterized in that: A third mixer (4.1) is arranged inside the anammox tank (4). A draft tube (4.2) is arranged outside the third mixer (4.1). A second biological filler (4.3) is arranged inside the anammox tank (4). One side of the anammox tank (4) is connected with a second raw water inlet pipe (4.4), and the second raw water inlet pipe (4.4) is connected with the first raw water inlet pipe (1.1). An on-line nitrite nitrogen detector (4.6) and an on-line ammonia nitrogen detector (4.7) are installed outside the anammox tank (4). An aeration system (5.1) is arranged inside the aeration tank (5), and an overflow wall (5.2) is installed inside the aeration tank (5).

6. The integrated denitrification and phosphorus removal bioreactor according to claim 1, characterized in that: Inside the sedimentation tank (6), there is a sedimentation water distribution and degassing tank (6.1). Inside the sedimentation tank (6), there is inclined tube packing (6.2). At the inner bottom of the sedimentation tank (6), there is a sludge hopper (6.3). Through holes (6.4) are formed on the inner wall of the sedimentation tank (6). One side of the sedimentation tank (6) is connected to a water outlet pipe (6.5). Inside the sedimentation tank (6), there is a reflux tank (6.6). Inside the thickening tank (7), there is a water distribution tank (7.1). One side of the thickening tank (7) is connected to a sludge discharge pipe (7,2). The outer surface of the thickening tank (7) is connected to a drain pipe (7.3), and one end of the drain pipe (7.3) is connected to the phosphorus recovery device (8).

7. A process for an integrated biological reactor for nitrogen and phosphorus removal, characterized in that, For the integrated denitrification and phosphorus removal bioreactor according to any one of claims 1-6, it includes the following steps: In the first stage, the raw water inlet is divided into two paths. One path of the raw water is mixed with the reflux sludge and then enters the anaerobic tank (1), where anaerobic phosphorus release reaction occurs in the anaerobic tank (1). Subsequently, it is mixed with the drainage of the phosphorus recovery device (8) and the reflux nitrified liquid of the shortcut nitrification tank (3) and enters the denitrification tank (2) together. In the second stage, after being treated in the denitrification tank (2), it enters the shortcut nitrification tank (3) for shortcut nitrification reaction to oxidize ammonia nitrogen into nitrite nitrogen. Part of the mixed liquid in the shortcut nitrification tank (3) is refluxed to the denitrification tank (2) to supplement nitrite in the denitrification tank (2). In the third stage, the sewage after the reaction in the shortcut nitrification tank (3) is mixed with the other path of raw water and enters the anaerobic ammonium oxidation tank (4). The anaerobic ammonium oxidation bacteria use nitrite as an electron acceptor to oxidize ammonia nitrogen into nitrogen gas, and then enter the aeration tank (5) for aerobic phosphorus uptake, organic matter degradation, nitrification and nitrogen stripping. In the fourth stage, finally, it enters the sedimentation tank (6) for sedimentation and separation of mud and water. The sedimented sludge is refluxed to the thickening tank (7) and the anaerobic tank (1). The thickened sludge at the bottom of the thickening tank (7) is discharged as excess sludge, and the supernatant is discharged into the phosphorus recovery device (8) for phosphorus recovery. The sewage after phosphorus recovery is discharged into the denitrification tank (2).

8. The process of an integrated denitrification and phosphorus removal bioreactor according to claim 7 further includes, between the first stage and the fourth stage: In the reactor, each reaction tank forms a closed-loop circuit according to the technological process, and each tank is arranged in a ring shape. The connecting pipelines are short and the head loss is small.

9. The process of an integrated denitrification and phosphorus removal bioreactor according to claim 7 further includes, in the fourth stage: The supernatant of the thickening tank (7) is refluxed to the denitrification tank (2) after being treated by the phosphorus recovery device (8), and there is a reflux of the mixed liquid from the shortcut nitrification tank (3) to the denitrification tank (2).

10. The process of an integrated nitrogen and phosphorus removal bioreactor according to claim 7 further includes, in the third stage: The shortcut nitrification tank (3) adopts low-dissolved oxygen aeration. Packings are arranged in the shortcut nitrification tank (3) and the anaerobic ammonium oxidation tank (4), and the set volume ratio of the packings is ≤60%.

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