Integrated secondary AO biochemical reaction device

Abstract

The utility model provides an integrated two-stage AO biochemical reaction device. According to the integrated two-stage AO biochemical reaction device, an intermediate sedimentation tank of a conventional two-stage AO biochemical treatment process is omitted. Through the arrangement that the anaerobic reaction tank and the anoxic reaction tank are filled with biological stuffing and the setting of large-flow internal reflux sludge, the output of the sludge is reduced, so that the sludge entering the second-stage AO biochemical treatment tank is not too much to influence the operation of the second-stage AO biochemical treatment tank even if an intermediate sedimentation tank is not arranged. According to the treatment device disclosed by the utility model, an improved and simplified secondary A / O wastewater treatment system is integrally arranged in an integrated treatment device, so that the optimization and integration of a treatment process are realized, the treatment effect can be improved and better guaranteed, the occupied area of a treatment structure is minimized, and the treatment cost is reduced. And the construction period and the construction cost can be greatly reduced. The utility model provides an efficient, reliable and economical treatment device for the treatment of high-concentration organic wastewater.

Description

Technical Field

[0001] This utility model relates to the technical field of organic wastewater treatment, and in particular to a two-stage AO biochemical reaction device. Background Technology

[0002] The AO (anoxic-aerobic) biochemical reaction process, commonly used in wastewater treatment, is a system that effectively removes total nitrogen and COD from wastewater. This process includes an anoxic treatment section, an aerobic treatment section, and a sedimentation unit. Part of the settled sludge is returned to the inlet of the anoxic treatment section to replenish the acclimation microorganisms in the wastewater treatment system. An internal reflux system is implemented in the aerobic treatment tank, allowing a large amount of the mixed liquor to be returned to the anoxic treatment tank. This allows a significant amount of nitrate nitrogen produced by autotrophic nitrifying bacteria in the aerobic treatment tank to be returned to the anoxic treatment tank. In the anoxic treatment tank, heterotrophic denitrifying bacteria reduce the nitrate nitrogen to nitrogen gas, thus achieving biological denitrification. Simultaneously, the organic components in the wastewater are decomposed and utilized by denitrifying bacteria and aerobic heterotrophic bacteria in the treatment system, achieving the removal of BOD and COD. For high-concentration, recalcitrant organic wastewater or organic wastewater containing high concentrations of nitrogen and phosphorus, primary AO biological treatment often cannot completely remove BOD, COD, nitrogen, and phosphorus. In such cases, AAO or secondary AO biological treatment systems are often required to meet higher treatment standards. An AAO biological treatment system adds an anaerobic treatment stage before the primary AO biological treatment system to enhance biological phosphorus removal. This system utilizes facultative anaerobic phosphorus-accumulating bacteria growing in the treatment system, which completely release phosphorus under anaerobic conditions and extensively absorb phosphorus under aerobic conditions, achieving phosphorus removal through this phosphorus absorption and release process. A secondary AO biological treatment system performs a second AO biological treatment on top of the primary AO biological treatment to enhance COD and nitrogen removal.

[0003] Traditional AO, AAO, or two-stage AO biological treatment processes often have independent structures for each treatment stage. Such systems require a large area and space, especially when treating high-concentration organic wastewater or organic wastewater containing high concentrations of nitrogen and phosphorus (which often requires AAO or two-stage AO biological treatment processes). Due to the long treatment process, the residence time of each treatment stage varies, the types of reactions and the required conditions also differ, resulting in different sizes and shapes of the corresponding structures. Multiple treatment objectives need to be achieved, and multiple sludge recirculations are required. Since the various structures need to be connected by connecting pipes, the number of process pipelines is large, and the head loss of the water flowing through the structures will be greater, which will also increase the construction period and cost accordingly.

[0004] Traditional two-stage AO biological treatment processes often require the installation of intermediate sedimentation tanks to facilitate sludge removal and sludge return from the first-stage treatment stage. However, the installation of intermediate sedimentation tanks results in the entire system occupying more area and space.

[0005] In traditional AO systems, to achieve good denitrification, the flow rate of the internal recirculation section is 3-5 times the wastewater flow rate. This causes a large amount of dissolved oxygen in the aerobic tank mixed liquor to enter the anoxic tank, which may seriously affect the operating efficiency of the anoxic tank.

[0006] Conventional two-stage AO biological treatment processes cannot effectively remove phosphorus from wastewater, while conventional AAO biological treatment systems cannot achieve ideal results for wastewater containing high concentrations of COD and nitrogen. Utility Model Content

[0007] The purpose of this invention is to provide an improved and optimized integrated two-stage AO biochemical treatment device, which can be used to treat organic wastewater containing high concentrations of recalcitrant COD, nitrogen, and phosphorus. It features high efficiency, stability, and economy, and the treated wastewater can meet the standards for direct discharge.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] An integrated two-stage AO biochemical reactor is used to treat organic wastewater with high concentrations of nitrogen, phosphorus, and COD. It comprises, in sequence, a pH adjustment tank, a biological selection tank, an anaerobic reactor, a primary anoxic reactor, a primary aerobic reactor, an intermediate deaeration tank, a secondary anoxic reactor, a secondary aerobic reactor, and a baffle sedimentation tank. The pH adjustment tank introduces organic wastewater through a lift pump and an inlet pipe. A first distribution well and a second distribution well are arranged side-by-side on one side of the pH adjustment tank, and each of the first and second distribution wells is equipped with a distribution regulating weir. The first and second distribution weirs are used to distribute the flow rate of organic wastewater from the pH adjustment tank into the first and second distribution wells. The first distribution well is connected to the biological selection tank, and the second distribution well serves as a buffer zone for wastewater diverted to a bypass for parallel treatment. Biological packing materials are fixedly installed in the anaerobic reactor, the primary anoxic reactor, and the secondary anoxic reactor. A rotary flow mechanism is installed in both the primary and secondary anoxic reactors to drive the mixed liquor to rotate. The aerobic reaction tank provides the necessary oxygen for aerobic microorganisms. The secondary aerobic reaction tank is located downstream of the secondary anoxic reaction tank. The baffled sedimentation tank is located on one side of both the secondary aerobic and anoxic reaction tanks, and the upper spaces of the secondary aerobic and anoxic reaction tanks are equipped with sludge collection channels along the tank walls. The baffled sedimentation tank has an inlet distribution channel and an outlet channel. The inlet distribution channel is connected to the secondary aerobic reaction tank via a connecting hole nine, used to introduce the effluent from the secondary aerobic reaction tank into the sedimentation tank. The sedimentation zone is divided into two sections: a sedimentation area and a sludge collection channel. One end of the effluent channel is connected to a clear water well via a connecting pipe and a regulating valve to discharge clear water from the upper part of the sedimentation zone. The baffle sedimentation tank is equipped with a reciprocating sludge scraper to suck up the sedimented sludge accumulated at the bottom of the sedimentation zone through the suction pipe of the reciprocating sludge scraper and discharge it into the sedimented sludge collection channel. The sedimented sludge collection channel is connected to the sedimented sludge conveying channel via a connecting pipe and a connecting valve. The end of the sedimented sludge conveying channel is equipped with a sludge well and a sludge return control valve to discharge the sludge to the sludge dewatering system for dewatering and return.

[0010] Preferably, the biological packing material in the anaerobic reactor is one of the following: combined biological packing material, elastic biological packing material, and stacked unfolding biological carrier.

[0011] Preferably, the primary anoxic reaction tank is adjacent to the primary aerobic reaction tank, the secondary anoxic reaction tank, and the secondary aerobic reaction tank on one side;

[0012] The primary anoxic reaction tank adopts a rectangular structure. The rotary flow mechanism of the primary anoxic reaction tank includes a middle partition wall. The middle partition wall is arranged along the long side of the primary anoxic reaction tank. Two flow mixers are respectively provided on both sides of the middle partition wall to drive the mixed liquid inside the primary anoxic reaction tank to rotate around the middle partition wall.

[0013] Preferably, the four corners of the rectangular structure of the primary anoxic reaction tank and the secondary anoxic reaction tank are rounded to facilitate the smooth circulation of the internal mixed liquid around the intermediate partition wall.

[0014] Preferably, the secondary anoxic reaction tank adopts the same rectangular structure as the primary anoxic reaction tank, with a middle partition wall in the middle along the long side. Two flow mixers are respectively provided on both sides of the middle partition wall to drive the mixed liquid inside the secondary anoxic reaction tank to rotate around the middle partition wall.

[0015] Preferably, an internal reflux system is provided on one side of the intermediate deaeration tank. The internal reflux system includes an internal reflux collection well for the deaeration tank and an internal reflux channel connected to it. The internal reflux collection well for the deaeration tank is located inside the intermediate deaeration tank. An internal reflux lift pump is installed on the tank wall of the internal reflux collection well that contacts the intermediate deaeration tank. The outlet of the internal reflux lift pump is connected to the internal reflux collection well for the deaeration tank through a connecting pipe, for pumping the mixed liquor in the intermediate deaeration tank into the internal reflux collection well for the deaeration tank. The internal reflux channel is set along the inner side wall of the top of the primary aerobic reaction tank, the primary anoxic reaction tank, and the anaerobic reaction tank, and has an overall L-shaped structure. The internal reflux channel is connected to the primary anoxic reaction tank and the anaerobic reaction tank respectively through the regulating weir gate of the anoxic tank and the regulating weir gate of the anaerobic tank, for the internal reflux of the mixed liquor in the internal reflux collection well for the primary anoxic reaction tank and the anaerobic reaction tank respectively.

[0016] Preferably, the first water distribution well is connected to the biological selection tank through a connecting hole one, the biological selection tank is connected to the anaerobic reaction tank through a connecting hole two, and biological packing material is fixedly installed in the anaerobic reaction tank; the anaerobic reaction tank is connected to the primary anoxic reaction tank through a connecting hole three, and biological packing material is fixedly installed in the primary anoxic reaction tank; the primary aerobic reaction tank consists of two aerobic tanks, including primary aerobic tank one (7) and primary aerobic tank two (8), and the two aerobic tanks are interconnected through a connecting hole five, and the upper space of primary aerobic tank two (8) is provided with aeration along the tank wall near primary aerobic tank one (7). The main aeration corridor contains aeration main pipes. Aeration devices are distributed at the bottom of both aerobic tanks, and these devices are connected to the aeration main pipes within the corridor. The primary anoxic reaction tank is connected to the primary aerobic tank (first aerobic tank) via connecting hole four. The other primary aerobic tank (second aerobic tank) is connected to the intermediate deoxygenation tank via connecting hole six. The intermediate deoxygenation tank is connected to the secondary anoxic reaction tank via connecting hole seven. The secondary anoxic reaction tank is connected to the secondary aerobic reaction tank via connecting hole eight. The secondary aerobic reaction tank is connected to the inlet distribution channel of the baffle sedimentation tank via connecting hole nine.

[0017] Preferably, the pH adjustment tank is equipped with an online pH meter; the primary aerobic reaction tank is equipped with an online dissolved oxygen analyzer near the sixth connecting hole; the intermediate deaeration tank is equipped with an online nitrate nitrogen analyzer and an online dissolved oxygen analyzer at the seventh connecting hole; and the sludge conveying channel is equipped with a sludge return control float valve and an electromagnetic flow meter for controlling sludge return.

[0018] Preferably, the pH adjustment tank, the biological selection tank, and the anaerobic reaction tank are respectively equipped with a stirrer one, a stirrer two, and a stirrer three to provide hybrid power in the corresponding tanks.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The treatment device of this utility model integrates the improved and simplified secondary A / O wastewater treatment system into a single integrated treatment device, realizing the optimization and integration of the treatment process. This not only improves and ensures better treatment results, but also minimizes the footprint of the treatment structure, and significantly reduces the construction period and cost. This utility model can provide an efficient, reliable, and economical treatment device for the treatment of high-concentration, recalcitrant organic wastewater.

[0021] (2) This utility model eliminates the intermediate sedimentation tank in the conventional two-stage AO biological treatment process. By filling the anaerobic and anoxic reaction tanks with biological packing materials and setting a large flow rate of internal sludge return, the amount of sludge generated is reduced. Thus, even without an intermediate sedimentation tank, the amount of sludge entering the second-stage AO biological treatment tank will not be excessive and will not affect their operation.

[0022] (3) The present invention adds an anaerobic reaction tank, which enables the system to have the characteristics of AAO biochemical treatment, enhances the phosphorus removal effect of the system, and thus enables the system to have high-efficiency biological phosphorus removal performance.

[0023] (4) This utility model adds a biological selection tank and an intermediate deoxygenation tank, which can significantly reduce the amount of dissolved oxygen brought into the anaerobic tank, the primary anoxic tank and the secondary anoxic tank by the influent and sludge return and internal return, thus optimizing and improving the operation of these reaction tanks.

[0024] (5) The primary anoxic tank and the secondary anoxic tank of this utility model are rectangular tanks with partition walls in the middle and rounded corners at the four corners, so that the mixed liquid can flow smoothly in the reaction tank. This design makes the organic load, sludge concentration, reaction rate and microbial community structure at different locations in the tank vary in a gradient, thus making the system more resistant to shock and the treatment effect more guaranteed.

[0025] (6) The sedimentation tank of this utility model is a baffle sedimentation tank, which is compatible with the rectangular layout of existing treatment structures. The inlet, outlet and sludge discharge are all on one side of the sedimentation tank, which reduces the space occupied by the clear water and sludge discharge pipes and the entire sedimentation tank.

[0026] In summary, this invention includes an anoxic treatment section, an aerobic treatment section, and a sedimentation unit. Part of the settled sludge is returned to the treatment system inlet (biological selection tank) to replenish the acclimated microorganisms in the wastewater treatment system. An internal recirculation system is installed in a corner of the intermediate deaeration tank, near the secondary anoxic reaction tank and the primary aerobic reaction tank. The mixed liquor from the intermediate deaeration tank is pumped into the recirculation collection well within the deaeration tank and then lifted into the internal recirculation channel for internal recirculation. The mixed liquor from the recirculation collection well in the deaeration tank is then recirculated through the internal recirculation channel into the primary anoxic reaction tank and the anaerobic reaction tank respectively. This allows a large amount of nitrate nitrogen produced by autotrophic nitrifying bacteria in the primary aerobic reaction tank to be returned to the primary anoxic reaction tank. Under the action of heterotrophic denitrifying bacteria in the primary anoxic reaction tank, the nitrate nitrogen is reduced to nitrogen gas, thus achieving biological denitrification. Simultaneously, the organic components in the wastewater are decomposed and utilized by denitrifying bacteria and aerobic heterotrophic bacteria in the treatment system, achieving the removal of BOD and COD. Attached Figure Description

[0027] Figure 1A schematic diagram of the plan layout of an integrated device for a two-stage AO biochemical treatment system provided for an embodiment of this utility model;

[0028] Figure 2 A process flow diagram of a two-stage AO biochemical treatment system provided for an embodiment of this utility model.

[0029] The serial numbers in the diagram are as follows:

[0030] 1. pH Adjustment Tank; 1-1. Water Distribution Adjustment Weir I; 1-2. Water Distribution Adjustment Weir II; 1-3. Agitator I; 1-4. Online pH Analyzer; 2. First Water Distribution Well; 2-1. Connecting Hole I; 3. Second Water Distribution Well; 4. Biological Selection Tank; 4-1. Connecting Hole II; 4-2. Agitator II; 5. Anaerobic Reactor; 5-1. Connecting Hole III; 5-2. Agitator III; 6. Primary Anoxic Reactor; 6-1. Connecting Hole IV; 6-2. Flow Mixer I; 7. Primary Aerobic Tank I; 7-1. Connecting Hole V; 8. Primary Aerobic Tank II; 8-1. Connecting Hole VI; 8-2. Online Dissolved Oxygen Analyzer I; 9. Intermediate Deoxygenation Tank; 9-1. Connecting Hole VII; 9-2. Internal Recirculation Pump; 9-3. Online Nitrate Nitrogen Analyzer; 9-4. Online Dissolved Oxygen Analyzer II; 9 -5. Intermediate deaeration tank mixer; 10. Secondary anoxic reaction tank; 10-1. Connecting hole eight; 10-2. Flow mixer two; 11. Secondary aerobic reaction tank; 11-1. Connecting hole nine; 12. Baffle sedimentation tank; 12-1. Inlet water distribution channel; 12-2. Outlet water channel; 12-3. Clear water well; 12-4. Regulating valve; 12-5. Reciprocating sludge scraper; 13. Deaeration tank internal return water collection well; 14. Internal return channel; 14-1. Anoxic tank regulating weir; 14-2. Anaerobic tank regulating weir; 15. Sedimented sludge collection channel; 15-1. Connecting valve; 16. Sedimented sludge conveying channel; 16-1. Sludge return control float switch valve; 16-2. Electromagnetic flow meter; 16-3. Sludge well; 16-4. Sludge dewatering system; 17. Aeration main corridor. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0032] like Figure 1As shown, this embodiment discloses an integrated two-stage AO biochemical reactor for treating high-concentration nitrogen, phosphorus, and COD organic wastewater. It includes a pH adjustment tank 1, water distribution wells 2 and 3, a biological selection tank 4, an anaerobic reaction tank 5, a primary anoxic reaction tank 6, a primary aerobic reaction tank including a primary aerobic tank 1 7 and a primary aerobic tank 2 8, an intermediate deoxygenation tank 9, a secondary anoxic reaction tank 10, a secondary aerobic reaction tank 11, and a baffle sedimentation tank 12.

[0033] pH adjustment tank 1 is rectangular in plan shape, and organic wastewater is introduced through a lift pump and an inlet pipe; a first distribution well 2 and a second distribution well 3 are arranged side by side on one side of pH adjustment tank 1, and the other two sides are adjacent to biological selection tank 4.

[0034] A connecting hole is provided in the partition wall between pH adjustment tank 1, first water distribution well 2 and second water distribution well 3. Water distribution regulating weir gate 1-1 and water distribution regulating weir gate 1-2 are respectively provided in the connecting hole to distribute the flow of wastewater from pH adjustment tank 1 into first water distribution well 2 and second water distribution well 3.

[0035] The first distribution well 2 is adjacent to one side of the biological selection tank 4 and is connected to the biological selection tank 4 through the connecting hole 2-1. It is used to mix with the returned sludge. The second distribution well 3 is adjacent to one side of the first distribution well 2. The second distribution well 3 is used to divert part of the wastewater into the bypass for parallel treatment when needed.

[0036] Furthermore, in this embodiment, the pH adjustment tank 1 is equipped with a stirrer 1-3 and an online pH detector 1-4.

[0037] The biological selection tank 4 has a hexagonal shape with missing corners. It is adjacent to the anaerobic reaction tank 5 and the primary aerobic tank 7 on one side respectively. It has a connecting hole 4-1 in the partition wall with the anaerobic reaction tank 5. The biological selection tank 4 is equipped with a stirrer 4-2.

[0038] The anaerobic reactor 5 is rectangular. It is adjacent to the first-stage anoxic reactor 6 and the first-stage aerobic reactor on one side. The partition wall between the anaerobic reactor 5 and the first-stage anoxic reactor 6 is provided with a connecting hole 3 5-1. The anaerobic reactor 5 is equipped with a stirrer 3 5-2. Biological packing materials (such as combined biological packing materials, elastic biological packing materials, stacked unfolding biological carriers, etc.) are fixedly installed in the anaerobic reactor 5.

[0039] The primary anoxic reaction tank 6 has a rectangular plan shape. It is adjacent to the primary aerobic reaction tank 7, the secondary anoxic reaction tank 10, and the secondary aerobic reaction tank 11 on one side. The partition wall between the primary anoxic reaction tank 6 and the primary aerobic reaction tank 7 has a connecting hole 4 6-1. Biological packing material is fixedly installed inside the primary anoxic reaction tank 6.

[0040] Furthermore, in this embodiment, the four corners of the primary anoxic reaction tank 6 are rounded, and a middle partition wall is provided along the long side of the interior. At least one set (two) of flow mixers 6-2 are provided to drive the internal mixture to circulate around the middle partition wall. The rounded corners of the rectangular structure of the primary anoxic reaction tank 6 facilitate smooth circulation of the internal mixture around the middle partition wall.

[0041] The primary aerobic reaction tank consists of two aerobic tanks: Primary Aerobic Tank 1 (7) and Primary Aerobic Tank 2 (8), which are arranged one after the other. Primary Aerobic Tank 1 (7) and Primary Aerobic Tank 2 (8) are interconnected through a connecting hole 5 (7-1). The upper space of Primary Aerobic Tank 1 (7) is provided with an aeration main channel corridor 17 along the side wall adjacent to Primary Aerobic Tank 2 (8). An aeration main is laid in the aeration main channel corridor 17. Aeration devices are distributed on the bottom of the two aerobic tanks, and the aeration devices are respectively connected to the aeration main in the aeration main channel corridor 17; these devices are used to provide the oxygen required by the aerobic microorganisms.

[0042] The first-stage aerobic tank 7 has a rectangular plan shape and is adjacent to the first-stage aerobic tank 8, the intermediate deoxygenation tank 9, and the second-stage anoxic reaction tank 10 on one side.

[0043] The first-stage aerobic tank 28 has a rectangular plan shape. The first-stage aerobic tank 28 is adjacent to the intermediate deoxygenation tank 9 on one side. A connecting hole 6 8-1 is provided in the partition wall between the first-stage aerobic tank 28 and the intermediate deoxygenation tank 9. An online dissolved oxygen analyzer 1 8-2 is installed in the first-stage aerobic tank 28 near the connecting hole 5 7-1.

[0044] The intermediate deoxygenation tank 9 has a rectangular plan shape and is adjacent to the secondary anoxic reaction tank 10 on one side. A connecting hole 9-1 is provided in the partition wall between the intermediate deoxygenation tank 9 and the secondary anoxic reaction tank 10. An online nitrate nitrogen analyzer 9-3 and an online dissolved oxygen analyzer 9-4 are installed in the intermediate deoxygenation tank 9 near the connecting hole 9-1. A mixing agitator 9-5 is installed in the intermediate deoxygenation tank 9.

[0045] Furthermore, in this embodiment, an internal reflux system is provided in a corner of the intermediate deoxygenation tank 9, near the secondary anoxic reaction tank 10 and the primary aerobic tank 7. The internal recirculation system includes an internal recirculation collection well 13 in the deaeration tank and an internal recirculation channel 14 connected to it. There are through-wall holes in the partition wall between the internal recirculation collection well 13 in the deaeration tank and the intermediate deaeration tank 9. The outlet pipes of two sets of internal recirculation lift pumps 9-2 are arranged in the through-wall holes to pump the mixed liquor in the intermediate deaeration tank 9 into the internal recirculation collection well 13 in the deaeration tank and lift it into the internal recirculation channel 14 for internal recirculation. The internal recirculation channel 14 is set along the inner side wall of the top of the primary aerobic tank 7, the primary anoxic reaction tank 6, and the anaerobic reaction tank 5. It has an overall L-shaped structure. The internal recirculation channel 14 is equipped with an anoxic tank regulating weir 14-1 and an anaerobic tank regulating weir 14-2, which lead to the primary anoxic reaction tank 6 and the anaerobic reaction tank 5, respectively. It is used to allow the mixed liquor in the internal recirculation collection well 13 in the deaeration tank to enter the primary anoxic reaction tank 6 and the anaerobic reaction tank 5 through the internal recirculation channel 14 for internal recirculation.

[0046] The secondary anoxic reactor 10 has a rectangular plan shape. It is adjacent to the baffle sedimentation tank 12 and the secondary aerobic reactor 11 on one side. A connecting hole 10-1 is provided in the partition wall between the secondary anoxic reactor 10 and the secondary aerobic reactor 11. The four corners of the secondary anoxic reactor 10 are rounded, and a central partition wall is located along the long side of the interior. At least one set (two) of flow mixers 10-2 are provided to drive the internal mixed liquid to circulate around the central partition wall. A sludge collection channel 15 is provided along the tank wall in the upper space of the side of the secondary anoxic reactor 10 adjacent to the baffle sedimentation tank 12. Biological packing material is fixedly installed inside the secondary anoxic reactor 10. The rounded corners of the rectangular structure of the secondary anoxic reactor 10 facilitate the smooth circulation of the internal mixed liquid around the central partition wall.

[0047] The secondary aerobic reactor 11 has a rectangular plan shape and is located downstream of the secondary anoxic reactor 10. The baffle sedimentation tank 12 is located on the same side as both the secondary aerobic reactor 11 and the secondary anoxic reactor 10. A connecting hole 11-1 is provided in the partition wall between the inlet and outlet water distribution channels of the secondary aerobic reactor 11 and the baffle sedimentation tank 12. A sludge collection channel 15 is provided along the wall of the upper space of the secondary aerobic reactor 11, and it communicates with the sludge collection channel 15 provided along the wall of the upper space of the secondary anoxic reactor 10.

[0048] Aeration devices are distributed at the bottom of the secondary aerobic reaction tank 11, and the aeration devices are connected to the aeration main pipe placed in the aeration main pipe corridor 17.

[0049] The baffled sedimentation tank 12 has a rectangular plan shape. An inlet distribution channel 12-1 and an outlet channel 12-2 are located on the top of one side of the tank, on the same side as the sedimentation sludge collection channel 15. One end of the outlet channel 12-2 is connected to a regulating valve 12-4 via a connecting pipe to a clear water well 12-3, used to discharge clear water from the upper part of the sedimentation zone. The inlet distribution channel 12-1 is connected to the secondary aerobic reactor 11 via a connecting hole 11-1, used to introduce the effluent from the secondary aerobic reactor 11 into the sedimentation zone.

[0050] A reciprocating scraper 12-5 is installed in the baffle sedimentation tank 12 to suck up the sedimented sludge accumulated at the bottom of the sedimentation zone through the suction pipe of the reciprocating scraper 12-5 and discharge it into the sedimented sludge collection channel 15. The sedimented sludge collection channel 15 is connected to the sedimented sludge conveying channel 16 through a connecting pipe and a connecting valve 15-1. At the end of the sedimented sludge conveying channel 16, there is a sludge well 16-3, a sludge return control float switch valve 16-1 and an electromagnetic flow meter 16-2, which are used to discharge the sludge to the sludge dewatering system 16-4 for dewatering and to return part of the sludge to the biological selection tank 4.

[0051] like Figure 2 As shown, the following details the specific parameters:

[0052] A certain company's integrated polyamide project generates wastewater from various sources, including caprolactam unit, fuming sulfuric acid unit, polymerization unit, laboratory drainage, domestic sewage, initial rainwater from the plant area, boiler drainage, and concentrated water from the wastewater reuse unit. The total designed wastewater volume is 600 m³. 3 / h, to be implemented in two phases, with the first phase having a processing capacity of 300m³ / h. 3 / h.

[0053] Wastewater first enters pH adjustment tank 1 via a booster pump and inlet pipe. Acid and alkali solutions are added to the tank via dosing pumps, acid addition pipes, and alkali addition pipes. Mixing agitators 1-3 installed in the tank provide hybrid mixing, ensuring thorough mixing of the wastewater and the added acids and alkalis. Online pH meters 1-4 installed in pH adjustment tank 1 automatically monitor the pH of pH adjustment tank 1, controlling the pH between 6.5 and 8.0. Distribution regulating weirs 1-1 and 1-2 at the outlet of pH adjustment tank 1 are used to regulate the flow of wastewater into the first distribution well 2 and the second distribution well 3, respectively. In the first phase, distribution regulating weir 1-2 is closed, directing all wastewater to the first distribution well 2. After the second phase is implemented, distribution regulating weir 1-2 is opened, allowing 50% of the total wastewater to flow into the second distribution well 3 and be sent to the second-phase treatment facility for parallel treatment.

[0054] The effluent from the first distribution well 2 enters the biological selector tank 4 and is mixed with the returned sludge. Dissolved oxygen introduced into the wastewater is eliminated by aerobic microorganisms, thus ensuring strict anaerobic conditions in the subsequent anaerobic reactor 5. Microorganisms in the returned sludge, especially facultative phosphorus-accumulating bacteria, nitrifying bacteria, and denitrifying bacteria, are revitalized and replenished in the biological selector tank. Two mixing agitators 4-2 installed in the biological selector tank 4 provide the power for mixing the wastewater and sludge.

[0055] The effluent from biological selector tank 4 enters anaerobic reactor 5 and mixes with some of the internal return liquid flowing in from the regulating weir 14-2 of the internal return system. In anaerobic reactor 5, some large-molecule organic matter or recalcitrant organic matter in the wastewater undergoes hydrolysis under the action of obligate anaerobic bacteria, producing small-molecule organic matter such as fatty acids. Phosphorus-accumulating bacteria decompose polymerized phosphorus in their bodies under anaerobic conditions, preparing for proliferation and phosphorus accumulation in the subsequent aerobic treatment section. Two mixing agitators 5-2 installed in anaerobic reactor 5 provide the hybrid power required for the reaction. The stacked expandable biological carrier installed in anaerobic reactor 5 provides an anchoring site for microorganisms in anaerobic reactor 5, increasing the sludge concentration in anaerobic reactor 5 and reducing the amount of sludge produced.

[0056] The effluent from anaerobic reactor 5 enters the primary anoxic reactor 6, where it mixes with a large amount of internal return sludge flowing in from the regulating weir 14-1 of the anoxic reactor. Within the primary anoxic reactor 6, nitrate nitrogen from the internal return liquid and the upstream treatment tank is reduced to nitrogen gas by heterotrophic denitrifying bacteria. Driven by two sets (four in total) of horizontal flow promoters 6-2 within the primary anoxic reactor 6, the internal mixed liquid circulates around the central partition wall, resulting in a plug flow pattern. This creates a gradient distribution of sludge concentration, organic load, dissolved oxygen level, and biological reaction rate between the inlet and outlet of the reactor, which helps ensure good treatment efficiency and stability. The stacked, expandable biological carriers installed in the primary anoxic reactor 6 provide an anchorage site for microorganisms within the anoxic reactor, increasing the sludge concentration and reducing sludge production.

[0057] The effluent from the primary anoxic reactor 6 then sequentially enters the primary aerobic reactor 7 and the primary aerobic reactor 8. In the aerobic reactors, low-molecular-weight organic matter is completely oxidized into CO2 and water by aerobic heterotrophic bacteria. Ammonia nitrogen is converted into nitrate nitrogen by ammonia-oxidizing microorganisms. The generated nitrate nitrogen is then returned to the anaerobic reactor 5 and the primary anoxic reactor 6 for denitrification. The remaining nitrate nitrogen enters the secondary anoxic reactor for denitrification. Phosphorus-accumulating bacteria excessively absorb and store phosphorus under aerobic conditions, eventually entering the settled sludge and being discharged from the system through the excess sludge. The oxygen required by the aerobic microorganisms is provided by aeration devices laid at the bottom of the reactors. Air supplied by high-pressure blowers is delivered to each aeration head of the aeration devices through the aeration main pipe, thus entering the reaction liquid. An online dissolved oxygen analyzer 8-2, located near the connecting hole 7-1 in the primary aerobic reactor 8, monitors the dissolved oxygen level in the aerobic reactor and controls the blower flow accordingly, maintaining the dissolved oxygen concentration at 2-3 mg / L.

[0058] The effluent from the primary aerobic tank 28 then enters the intermediate deaeration tank 9. The intermediate deaeration tank 9 is not equipped with an aeration device; its hybrid power is provided by two mixing agitators 9-5. The dissolved oxygen brought in by the influent to the intermediate deaeration tank 9 is completely consumed by the aerobic microorganisms, ensuring that the anoxic conditions of the subsequent secondary anoxic reactor 10 and the internal return sludge are free of dissolved oxygen, thereby avoiding the impact of dissolved oxygen on the operation of the anaerobic reactor 5 and the primary anoxic reactor 6. The deaerator reflux collection well 13 and two internal reflux lift pumps 9-2 installed on its partition wall pump part of the mixed liquor into the deaerator reflux collection well 13 and lift it, so that the internal reflux liquid can enter the internal reflux channel 14 and be transported to the anaerobic reaction tank 5 and the primary anoxic reaction tank 6. A large amount of nitrate nitrogen in the internal reflux liquid can be reduced to nitrogen gas in these reaction tanks to achieve denitrification. The online nitrate nitrogen analyzer 9-3 and the online dissolved oxygen analyzer 9-4 installed near the connecting hole 9-1 in the intermediate deaerator 9 monitor the concentration of nitrate nitrogen and dissolved oxygen in the mixed liquor in the tank. The concentrations of nitrate nitrogen and dissolved oxygen are 8-10 mg / L and 0-1 mg / L, respectively.

[0059] The effluent from the intermediate deaeration tank 9 then enters the secondary anoxic reactor 10. In the secondary anoxic reactor 10, the remaining nitrate nitrogen is reduced to nitrogen gas by heterotrophic denitrifying bacteria. The remaining organic matter undergoes further hydrolysis under anoxic conditions, increasing the B / C ratio of the mixed liquor. Driven by a set (two) of horizontal flow promoters 10-2 within the secondary anoxic reactor 10, the internal mixed liquor flows in a rotating manner around the intermediate partition wall, resulting in a plug flow pattern. This creates a gradient distribution of sludge concentration, organic load, dissolved oxygen level, and biological reaction rate between the inlet and outlet of the reactor, which is beneficial for ensuring good treatment efficiency and stability. The stacked, expandable biological carriers installed in the secondary anoxic reactor 10 provide an anchorage site for microorganisms within the reactor, increasing the sludge concentration and reducing sludge production.

[0060] The effluent from the secondary anoxic reactor 10 then enters the secondary aerobic reactor 11. Here, the remaining organic matter entering this reactor is completely oxidized into CO2 and water by aerobic heterotrophic bacteria, and the remaining ammonia nitrogen is completely converted into nitrate nitrogen by ammonia-oxidizing microorganisms. The oxygen required by the aerobic microorganisms is provided by aeration devices laid at the bottom of the reactor, and air supplied by a high-pressure blower is transported to the aeration devices through the aeration main pipe.

[0061] The effluent from the secondary aerobic reaction tank 11 then enters the inlet distribution channel 12-1 of the baffle sedimentation tank 12 and enters the sedimentation zone. The clear water in the upper part of the sedimentation zone enters the effluent channel 12-2. The clear water entering the effluent channel 12-2 is connected to the clear water well 12-3 for discharge through the regulating valve 12-4. The sedimented sludge accumulated at the bottom of the sedimentation zone is sucked in by the suction pipe of the reciprocating sludge scraper 12-5 and discharged into the sedimented sludge collection channel 15. It is then transported to the sludge well 16-3 through the connecting valve 15-1 and the sedimented sludge conveying channel 16 and discharged to the sludge dewatering system 16-4 for dewatering. A portion of the sludge is returned to the biological selection tank 4 through the sludge return control float switch valve 16-1 set in the sludge well 16-3. The electromagnetic flow meter 16-2 is used to control and measure the amount of returned sludge.

[0062] Table 1. Main water quality indicators of the influent and effluent of the wastewater treatment device in Example 1 (unit: mg / L)

[0063]

[0064] The main structures of the secondary AO biochemical treatment system in this embodiment are integrated into an integrated structure with a cuboid shape. Adjacent treatment units are separated by pool walls. The treatment structures connected one after the other according to the treatment process flow are connected by connecting holes in the partition walls. The flow of wastewater from the inlet to the effluent channel of the final sedimentation tank is driven by gravity flow and a pusher agitator.

[0065] In summary, this invention includes an anoxic treatment section, an aerobic treatment section, and a sedimentation unit. Part of the settled sludge is returned to the treatment system inlet to replenish the acclimation microorganisms in the wastewater treatment system. An internal recirculation system is installed in a corner of the intermediate deaeration tank, near the secondary anoxic reaction tank and the primary aerobic reaction tank. The mixed liquor from the intermediate deaeration tank is pumped into the recirculation collection well within the deaeration tank and then lifted into the internal recirculation channel for internal recirculation. The recirculated liquid then enters the primary anoxic reaction tank and the anaerobic reaction tank respectively. This allows a large amount of nitrate nitrogen produced by autotrophic nitrifying bacteria in the primary aerobic reaction tank to be returned to the primary anoxic reaction tank. Under the action of heterotrophic denitrifying bacteria in the primary anoxic reaction tank, the nitrate nitrogen is reduced to nitrogen gas, thus achieving biological denitrification. Simultaneously, the organic components in the wastewater are decomposed and utilized by denitrifying bacteria and aerobic heterotrophic bacteria in the treatment system, achieving the removal of BOD and COD.

[0066] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0067] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0068] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An integrated two-stage AO biochemical reaction device for treating organic wastewater with high concentrations of nitrogen, phosphorus and COD, characterized in that, It comprises pH adjusting tank (1), biological selection tank (4), anaerobic reaction tank (5), first-stage anoxic reaction tank (6), first-stage aerobic reaction tank, intermediate oxygen-consuming tank (9), second-stage anoxic reaction tank (10), second-stage aerobic reaction tank (11) and baffle settling tank (12) connected in sequence; The pH adjusting tank (1) introduces organic wastewater through a lifting pump and a water inlet pipe; a first water distribution well (2) and a second water distribution well (3) are arranged side by side on one side of the pH adjusting tank (1); a water distribution adjusting gate one (1-1) and a water distribution adjusting gate two (1-2) are arranged on the first water distribution well (2) and the second water distribution well (3) respectively, for distributing the flow of the organic wastewater in the pH adjusting tank (1) into the first water distribution well (2) and the second water distribution well (3). The first water distribution well (2) is communicated with the biological selection tank (4), and the second water distribution well (3) is used as a buffer zone for shunt to enter a bypass for parallel processing. Biological fillers are fixedly arranged in the anaerobic reaction tank (5), the first-stage anoxic reaction tank (6) and the second-stage anoxic reaction tank (10); and a rotary flow mechanism is arranged in the first-stage anoxic reaction tank (6) and the second-stage anoxic reaction tank (10) for driving the mixed liquid to rotate and flow. The first-stage aerobic reaction tank is used for providing oxygen required by aerobic microorganisms. The second-stage aerobic reaction tank (11) is arranged on the downstream side of the second-stage anoxic reaction tank (10); the baffle settling tank (12) is arranged on one side of the second-stage aerobic reaction tank (11) and the second-stage anoxic reaction tank (10), and a sludge collection channel (15) is arranged along the wall of the upper space of the second-stage aerobic reaction tank (11) and the second-stage anoxic reaction tank (10). The baffle settling tank (12) is provided with a water inlet distribution channel (12-1) and a water outlet channel (12-2); the water inlet distribution channel (12-1) is communicated with the second-stage aerobic reaction tank (11) through a communication hole nine (11-1), for introducing the outflow of the second-stage aerobic reaction tank (11) into the settling zone; One end of the water outlet channel (12-2) is communicated with a regulating valve (12-4) through a communication pipe to a clear water well (12-3), for discharging the clear water in the upper part of the settling zone; A reciprocating type sludge scraping and sucking machine (12-5) is arranged in the baffle settling tank (12), for sucking and discharging the sludge accumulated at the bottom of the settling zone into the sludge collection channel (15) through the sucking pipe of the reciprocating type sludge scraping and sucking machine (12-5); the sludge collection channel (15) is communicated with a sludge conveying channel (16) through a communication pipe and a communication valve (15-1); and the sludge conveying channel (16) is provided with a sludge well (16-3) at the tail end, for discharging to a sludge dewatering system (16-4) for dewatering.

2. The integrated two-stage AO biochemical reaction device according to claim 1, characterized in that, The biological fillers in the anaerobic reaction tank (5) can be any one of the biological fillers including combined biological fillers, elastic biological fillers and laminated expansion type biological carriers.

3. The integrated two-stage AO biochemical reaction device according to claim 1, characterized in that, The primary anoxic reaction tank (6) is adjacent to one side of the primary aerobic reaction tank, the secondary anoxic reaction tank (10) and the secondary aerobic reaction tank (11); The primary anoxic reaction tank (6) adopts a rectangular structure, and the rotary flow mechanism of the primary anoxic reaction tank (6) comprises a middle partition wall arranged along the long side direction in the primary anoxic reaction tank (6), and two push-flow mixers I (6-2) are arranged on the two sides of the middle partition wall respectively, for driving the mixed liquid in the primary anoxic reaction tank (6) to rotate around the middle partition wall.

4. The integrated two-stage AO biochemical reaction device according to claim 3, characterized in that, The secondary anoxic reaction tank (10) adopts the same rectangular structure as the primary anoxic reaction tank (6), and a middle partition wall is arranged along the long side direction in the middle of the secondary anoxic reaction tank (10), and two push-flow mixers II (10-2) are arranged on the two sides of the middle partition wall respectively, for driving the mixed liquid in the secondary anoxic reaction tank (10) to rotate around the middle partition wall.

5. The integrated two-stage AO biochemical reaction device according to claim 3, characterized in that, The four corners of the rectangular structure of the primary anoxic reaction tank (6) and the secondary anoxic reaction tank (10) are all chamfered, so that the mixed liquid in the primary anoxic reaction tank (6) and the secondary anoxic reaction tank (10) can rotate around the middle partition wall smoothly.

6. The integrated two-stage AO biochemical reaction device according to claim 1, characterized in that, One side of the middle deoxygenation tank (9) is provided with an internal reflux system, which comprises a deoxygenation tank internal reflux sump (13) and an internal reflux channel (14) connected thereto; the deoxygenation tank internal reflux sump (13) is arranged in the middle deoxygenation tank (9), an internal reflux lifting pump (9-2) is installed on the tank wall of the deoxygenation tank internal reflux sump (13) in contact with the middle deoxygenation tank, and the outlet of the internal reflux lifting pump (9-2) is connected to the deoxygenation tank internal reflux sump (13) through a communication pipe, for pumping the mixed liquid in the middle deoxygenation tank (9) into the deoxygenation tank internal reflux sump (13); The internal reflux channel (14) is arranged along the inner side wall of the top of the primary aerobic reaction tank, the primary anoxic reaction tank (6) and the anaerobic reaction tank (5), and has an overall L-shaped structure; the internal reflux channel (14) is connected to the primary anoxic reaction tank (6) and the anaerobic reaction tank (5) through an anoxic tank regulating weir gate (14-1) and an anaerobic tank regulating weir gate (14-2) respectively, for allowing the mixed liquid in the deoxygenation tank internal reflux sump (13) to enter the primary anoxic reaction tank (6) and the anaerobic reaction tank (5) respectively through the internal reflux channel (14) for internal reflux.

7. The integrated two-stage AO biochemical reaction device according to claim 1, characterized in that, The first water distribution well (2) is connected to the biological selection tank (4) through a communication hole I (2-1), the biological selection tank (4) is connected to the anaerobic reaction tank (5) through a communication hole II (4-1), and biological fillers are fixedly arranged in the anaerobic reaction tank (5); The anaerobic reaction tank (5) is connected to the primary anoxic reaction tank (6) through a communication hole III (5-1), and biological fillers are fixedly arranged in the primary anoxic reaction tank (6); The first water distribution well (2) is connected to the biological selection tank (4) through a communication hole I (2-1), the biological selection tank (4) is connected to the anaerobic reaction tank (5) through a communication hole II (4-1), and biological fillers are fixedly arranged in the anaerobic reaction tank (5); The primary aerobic reaction tank adopts two aerobic tanks including a first-stage aerobic tank one (7) and a first-stage aerobic tank two (8), the two aerobic tanks are communicated with each other through a communication hole five (7-1), and a main aeration pipe gallery (17) is arranged in the upper space of the first-stage aerobic tank two (8) along the wall adjacent to the first-stage aerobic tank one (7), a main aeration pipe is arranged in the main aeration pipe gallery (17), and the corresponding bottoms of the two aerobic tanks are distributed with aeration devices which are communicated with the main aeration pipe in the main aeration pipe gallery (17) respectively; The first-stage anaerobic reaction tank (6) is communicated with the first-stage aerobic tank one (7) of the first-stage aerobic reaction tank through a communication hole four (6-1), and the other first-stage aerobic tank two (8) is communicated with the intermediate oxygen-consuming tank (9) through a communication hole six (8-1); The intermediate oxygen-consuming tank (9) is communicated with the second-stage anaerobic reaction tank (10) through a communication hole seven (9-1); The second-stage anaerobic reaction tank (10) is communicated with the second-stage aerobic reaction tank (11) through a communication hole eight (10-1), and the second-stage aerobic reaction tank (11) is communicated with the water inlet distribution channel (12-1) of the baffle sedimentation tank (12) through a communication hole nine (11-1).

8. The integrated two-stage AO biochemical reaction device according to claim 7, characterized in that, The pH adjusting tank (1) is provided with a pH on-line detector (1-4); The first-stage aerobic reaction tank is provided with a dissolved oxygen on-line analyzer one (8-2) above the communication hole six (8-1); The intermediate oxygen-consuming tank (9) is provided with a nitrate nitrogen on-line analyzer (9-3) and a dissolved oxygen on-line analyzer two (9-4) at the communication hole seven (9-1); The sedimentation sludge conveying channel (16) is provided with a sludge backflow control floating ball switch valve (16-1) and an electromagnetic flowmeter (16-2).

9. The integrated two-stage AO biochemical reaction device according to claim 1, characterized in that, The pH adjusting tank (1), the biological selection tank (4) and the anaerobic reaction tank (5) are respectively provided with a stirrer one (1-3), a stirrer two (4-2) and a stirrer three (5-2) for providing mixing power in the corresponding tanks.

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