An efficient multi-cycle integrated AAO treatment device and process

Abstract

The present invention relates to the technical field of sewage treatment, and particularly to an efficient multi-cycle integrated AAO treatment device and process. The device includes an anaerobic zone, an anoxic zone, a first aerobic zone, a second aerobic zone, a third aerobic zone, a water distribution zone, a double-layer secondary sedimentation tank, and a sludge pumping station. Partition walls and two oppositely arranged propellers are provided in the anoxic zone, the first aerobic zone, and the second aerobic zone. Guide walls are respectively provided at both ends of the partition walls. The propellers are arranged on both sides of the partition walls. The partition walls divide the anoxic zone into a first anoxic zone and a second anoxic zone, divide the first aerobic zone into a first stage of the first aerobic zone and a second stage of the first aerobic zone, and divide the second aerobic zone into a first stage of the second aerobic zone and a second stage of the second aerobic zone. Aeration devices are provided in the first aerobic zone, the second aerobic zone, and the third aerobic zone. The water distribution zone and the double-layer secondary sedimentation tank are constructed integrally with the AAO tank. The present invention can achieve the purpose of improving the sewage treatment efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly relates to a high-efficiency multi-cycle integrated AAO treatment device and process. Background Art

[0002] Currently, in sewage treatment, the mainstream biochemical treatment processes are oxidation ditch and AAO processes. The oxidation ditch process has a long sludge age and is prone to sludge bulking. The AAO process has conflicting requirements for nitrogen removal and phosphorus removal. The requirement for nitrogen removal is a lower organic load and a longer sludge age, while the requirement for phosphorus removal is a higher organic load and a shorter sludge age, which is often difficult to balance. Moreover, due to the anaerobic zone and anoxic zone being in the front, nitrates and dissolved oxygen in the external reflux and internal reflux sludge have an adverse impact on the anaerobic zone and anoxic zone, reducing the phosphorus removal and nitrogen removal efficiency. Therefore, there is an urgent need for a high-efficiency multi-cycle integrated AAO treatment device and process to solve this problem. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-efficiency multi-cycle integrated AAO treatment device and process to solve the above problems and achieve the purpose of improving sewage treatment efficiency.

[0004] To achieve the above purpose, the present invention provides the following solution: A high-efficiency multi-cycle integrated AAO treatment device includes an anaerobic zone, an anoxic zone, aerobic zone one, aerobic zone two, aerobic zone three, and a water distribution zone; partition walls and two oppositely arranged thrusters are respectively provided in the anoxic zone, aerobic zone one, and aerobic zone two. Guide walls are respectively provided at both ends of the partition walls. The thrusters are arranged on both sides of the partition walls. The partition wall in the anoxic zone divides the anoxic zone into anoxic zone one and anoxic zone two. The partition wall in the aerobic zone one divides the aerobic zone one into aerobic zone one stage one and aerobic zone one stage two. The partition wall in the aerobic zone two divides the aerobic zone two into aerobic zone two stage one and aerobic zone two stage two. Aeration devices are provided in the aerobic zone one, aerobic zone two, and aerobic zone three.

[0005] A high-efficiency multi-cycle integrated AAO treatment process, based on the above high-efficiency multi-cycle integrated AAO treatment device, includes the following steps:

[0006] Step 1: Anaerobic treatment, discharging the wastewater into the anaerobic zone for anoxic pretreatment;

[0007] Step 2: Anoxic treatment, discharging the anaerobically treated sewage into the anoxic zone to cause denitrification and anaerobic phosphorus release reactions of the sewage;

[0008] Step 3: Aerobic treatment, discharging the anoxically treated wastewater into the aerobic zone one and aerobic zone two, and combining with the aeration device to perform nitrification and aerobic phosphorus uptake treatment on the sewage;

[0009] Step 4: Sedimentation treatment. The sewage after aerobic treatment is discharged into the double-layer sedimentation area for sedimentation to obtain the treated sewage.

[0010] Preferably, in step 2, a carbon source dosing point is provided in the second anoxic zone, and a submersible camera is provided below the carbon source dosing point.

[0011] Preferably, the third aerobic zone and the second anoxic zone are connected by an internal reflux pump, and a valve and a flow meter are provided in the pipeline of the internal reflux pump.

[0012] Preferably, a nitrate nitrogen detector is provided at the inlet end of the anaerobic zone. When the total nitrogen detected by the nitrate nitrogen detector at the inlet end is higher than 45 mg / L, the nitrate nitrogen detector controls the aeration device in the first stage of the first aerobic zone to be closed through the PLC controller, so that the first stage of the first aerobic zone is converted into an anoxic state.

[0013] Preferably, an NH3-N detector and a COD detector are provided at the inlet end of the anaerobic zone. When the inlet NH3-N is greater than 40 mg / L and the inlet COD is less than 150 mg / L, the PLC controller controls the aeration device in the first stage of the second aerobic zone to be closed, so that the first stage of the second aerobic zone is in an anoxic state, forming a two-stage AO process.

[0014] Preferably, the baffle wall in the second aerobic zone is a flexible baffle wall, and a flexible guide rail is provided below the flexible baffle wall, and the flexible guide rail is driven by a waterproof motor; when the pollutant index in the anaerobic zone is low, the waterproof motor is started to straighten the flexible baffle wall on the left side of the second aerobic zone, and the sewage directly bypasses the second aerobic zone and enters the third aerobic zone. At the same time, the thruster in the second aerobic zone is turned off, and the aeration device in the second aerobic zone is adjusted to micro-aerate.

[0015] Preferably, a water distribution area and a water distribution splash wall are provided between the double-layer sedimentation area in step 4 and the third aerobic zone, and a sludge pumping station is provided on one side of the double-layer sedimentation area.

[0016] The present invention has the following technical effects: The thrusters of the present invention can play a role in pushing water flow. The cooperation of the two thrusters with the partition wall and the guide wall enables the water flow to flow around the partition wall, making the anoxic zone, aerobic zone I, and aerobic zone II present a state of mixing + plug flow during sewage treatment. In each individual aerobic zone, there is a state of plug flow and complete mixing, effectively overcoming short circuit flow and improving the buffering capacity. The inlet and outlet positions of each individual aerobic zone are close. The influent is well mixed and dispersed through the aeration device during circulation. The mixed liquid continues to circulate according to the action of the partition wall, guide wall, and thrusters. In this way, it presents a plug flow state in the short term (such as one cycle), and a mixing state in the long term (such as multiple cycles). The combination of the two enables the sewage to undergo at least one cycle and basically eliminate short circuit flow, and can provide a large dilution multiple to improve the buffering capacity, further enhancing the efficiency of sewage treatment. Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings:

[0018] Figure 1 It is a schematic plan view of the device of the present invention;

[0019] Figure 2 It is a process flow chart of the present invention;

[0020] Figure 3 It is a schematic structural view of the double-layer sedimentation zone of the present invention;

[0021] Among them, 1, influent port; 2, guide wall; 3, partition wall; 4, thruster; 5, internal reflux pump; 6, water distribution and splash wall. Detailed Description of the Preferred Embodiment

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0023] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0024] Refer to Figures 1-3, this embodiment provides an efficient multi-cycle integrated AAO treatment device, which includes an anaerobic zone, an anoxic zone, an aerobic zone I, an aerobic zone II, an aerobic zone III, and a water distribution zone; partition walls 3 and two oppositely arranged propellers 4 are respectively provided in the anoxic zone, the aerobic zone I, and the aerobic zone II. Guide walls 2 are respectively provided at both ends of the partition wall 3, and the two guide walls 2 are symmetrically arranged. The propellers 4 are arranged on both sides of the partition wall 3. The partition wall 3 in the anoxic zone divides the anoxic zone into an anoxic zone I and an anoxic zone II. The partition wall 3 in the aerobic zone I divides the aerobic zone I into an aerobic zone I stage 1 and an aerobic zone I stage 2. The partition wall 3 in the aerobic zone II divides the aerobic zone II into an aerobic zone II stage 1 and an aerobic zone II stage 2. Aeration devices are provided in the aerobic zone I, the aerobic zone II, and the aerobic zone III. An inlet 1 is provided in the anaerobic zone, and the sewage to be treated enters from the inlet 1.

[0025] The propeller 4 of the present invention can play a role in pushing the water flow. The two propellers 4 cooperate with the partition wall 3 and the guide wall 2 so that the water flow can flow around the partition wall 3, making the anoxic zone, the aerobic zone I, and the aerobic zone II present a mixed + plug-flow state during sewage treatment. There is a plug-flow and completely mixed state in each individual aerobic zone, effectively overcoming short-circuit flow and improving the buffering capacity. The inlet and outlet positions of each individual aerobic zone are close. The influent is well mixed and dispersed during the cycle through the aeration device. The mixed liquid continues to circulate according to the action of the partition wall 3, the guide wall 2, and the propeller 4. In this way, it is in a plug-flow state in the short term (such as one cycle), and in a mixed state in the long term (such as multiple cycles). The combination of the two makes the sewage go through at least one cycle and basically eliminates short-circuit flow, and can provide a large dilution multiple to improve the buffering capacity, further enhancing the efficiency of sewage treatment.

[0026] Specifically, the aeration device includes a blower, and a plurality of aeration pipes are connected to the outlet end of the blower. The aeration pipes are respectively connected to the aerobic zone I, the aerobic zone II, and the aerobic zone III.

[0027] Specifically, the aeration devices in the aerobic zone I, the aerobic zone II, and the aerobic zone III are all controlled by separate electric butterfly valves. By opening, closing, or adjusting the valve opening degree, a certain dissolved oxygen concentration gradient can be formed in each independent aerobic zone, which is suitable for the nitrification-denitrification process.

[0028] An efficient multi-cycle integrated AAO treatment device and process, based on an efficient multi-cycle integrated AAO treatment device, includes the following steps:

[0029] Step 1: Anaerobic treatment, discharging the wastewater into the anaerobic zone for anoxic pretreatment;

[0030] Step 2: Anoxic treatment, discharging the sewage after anaerobic treatment into the anoxic zone to cause denitrification and anaerobic phosphorus release reactions of the sewage;

[0031] Step 3: Aerobic treatment. Discharge the wastewater after anoxic treatment into the first aerobic zone and the second aerobic zone, and combine with the aeration device to carry out nitrification and aerobic phosphorus uptake treatment on the sewage.

[0032] Step 4: Sedimentation treatment. Discharge the sewage after aerobic treatment into the double-layer sedimentation zone for sedimentation to obtain the treated sewage.

[0033] For a further optimized solution, in step 2, a carbon source dosing point is provided in the second anoxic zone, and a submersible camera is provided below the carbon source dosing point, which helps to observe whether the medicine is added and the dosage of the added medicine. Refer to Figure 2 , push the carbon source to the dosing pipe through the carbon source dosing device, add the carbon source to the anoxic zone through the dosing pipe, and observe the carbon source addition situation with a submersible camera.

[0034] For a further optimized solution, the third aerobic zone and the second anoxic zone are connected through an internal reflux pump, and a valve and a flowmeter are provided in the pipeline of the internal reflux pump. At present, the advanced denitrification in sewage treatment plants is basically considered in the denitrifying deep bed filter, but the denitrification effect of the denitrifying deep bed filter is limited. Once the carbon source dosing amount exceeds the standard, it will increase the risk of effluent COD. The present invention considers adding a carbon source in the anoxic zone of the biochemical tank to share part of the total nitrogen removal function. Using the principle of post-feedback + equipment adjustment, a nitrate nitrogen detector and influent and effluent flow detectors are added at the front end and the end of the aerobic tank of the high-efficiency multi-cycle A2 / O tank. At the same time, a valve and a flowmeter are added to the reflux pipeline of the internal reflux pump, and the measured nitrate nitrogen data, influent water volume data, dissolved oxygen data, and internal reflux flow are integrated into the carbon source dosing system to accurately control the carbon source dosing amount. The dosing position is as Figure 1 shown, avoiding the internal reflux water pump, at a position 6m downstream of the internal reflux pump to reduce the influence of the internal reflux dissolved oxygen on the carbon source effect.

[0035] For a further optimized solution, a nitrate nitrogen detector is provided at the inlet end of the anaerobic zone. When the total nitrogen at the inlet end detected by the nitrate nitrogen detector is higher than 45mg / L, the nitrate nitrogen detector controls the aeration device in the first stage of the first aerobic zone to close through the PLC controller, so that the first stage of the first aerobic zone is converted into an anoxic state, increasing the residence time in the anoxic zone to meet the denitrification effect. At the same time, according to the value of the total nitrogen exceeding the standard, accurately calculate the additional reflux flow required by the internal reflux pump, and increase the reflux flow of the internal reflux pump, so that the final TN of the effluent from the biochemical tank is less than the design value.

[0036] For a further optimized solution, an NH3-N detector and a COD detector are installed at the inlet end of the anaerobic zone. When the influent NH3-N is greater than 40 mg / L and the influent COD is less than 150 mg / L, the PLC controller is used to control the aeration device in the first stage of the second aerobic zone to be turned off, making the first stage of the second aerobic zone in an anoxic state, thus forming a two-stage AO process. The two-stage AO process is divided into four stages: an anoxic stage (A1, the first and second anoxic zones), an aerobic stage (O1, the first aerobic zone), an anoxic stage (A2, the second aerobic zone is switched to an anoxic zone), and an aerobic stage (O2, the third aerobic zone). Conditions such as the dissolved oxygen, pH value, and sludge age in the O1 tank are controlled to achieve the nitrification reaction of ammonia nitrogen. By partially refluxing the mixed liquor in the O1 tank to the A1 tank, the carbon source in the raw water is fully utilized for denitrification and nitrogen removal, reducing the dosage of additional carbon source for denitrification and saving the operation cost; the A2 tank realizes denitrification and nitrogen removal by supplementing carbon source, and a relatively high dissolved oxygen is controlled in the O2 stage to further oxidize the residual carbon source and the remaining organic matter in the sewage, improving the performance of the activated sludge.

[0037] For a further optimized solution, the guide wall 2 located in the second aerobic zone is a flexible guide wall. A flexible guide rail is provided below the flexible guide wall, and the flexible guide rail is driven by a waterproof motor. The flexible guide rail can be selected from the flexible guide rail in the utility model patent with the application number 202122447905.1; when the pollutant index in the anaerobic zone is relatively low, the waterproof motor is started to straighten the flexible guide wall on the left side of the second aerobic zone, and the sewage directly bypasses the second aerobic zone and enters the third aerobic zone. At the same time, the thruster 4 in the second aerobic zone is turned off, and the aeration device in the second aerobic zone is adjusted to micro-aerate. The residence time of the sewage in the aerobic zone is not necessarily the longer the better. If the residence time is longer, there will be more microbial metabolites, and the effluent index will be worse. When the influent pollutant index is relatively low, such as low COD and TN, the residence time in the aerobic zone can be appropriately reduced. The flexible partition wall on the left side of the second aerobic zone is directly straightened to form a flexible partition wall, and the sewage directly bypasses the second aerobic zone and enters the third aerobic zone. The two stirrers in the second aerobic zone are stopped, and the air valve in the second zone is adjusted to micro-aerate to ensure that the sludge does not settle, which can reduce the power consumption and save the operation cost. The two thrusters 4 are stopped. The power of each stirrer is 5.5 kw. If stopped for 1 hour, 11 kw of electricity can be saved. At the same time, the aeration volume can be saved by about 1 / 5.

[0038] For a further optimized solution, a water distribution area and a water distribution splash wall 6 are provided between the double-layer sedimentation area and the third aerobic zone, and a sludge pumping station is provided on one side of the double-layer sedimentation area. A sedimentation area is added at the end of the third aerobic zone, and the surface load of the sedimentation area is 0.6 - 0.8 m 3 / m 2.h, a double - layer secondary sedimentation tank is adopted. The upper layer has a height of 5.1m (including a freeboard of 1m), and the lower layer has a height of 4.1m. The water inlet area uses a water distribution flower wall, and the water inlet holes are water inlet holes with a diameter of 200mm. The lower layer uses a hydraulic reciprocating sludge scraper, and the upper layer uses a horizontal flow scraping and sucking sludge machine. The equipment in the upper and lower layers operates independently without affecting each other. The double - layer secondary sedimentation tank shares a single effluent weir. By using a double - layer secondary sedimentation tank, the power consumption of the secondary sedimentation tank is about 1 / 2 less than that of a conventional single - layer secondary sedimentation tank. When combined with the biochemical tank, it reduces the hydraulic loss of the pipeline, reduces the oxygenation due to water drops, and is estimated to reduce the dissolved oxygen by 1mg / L. At the same time, the sludge pumping station is combined with the secondary sedimentation tank, and the pool walls share a common wall, saving floor area and construction cost.

[0039] An oxygen scavenger dosing area is added at the end of the aerobic zone 3. The oxygen scavenger is added from the oxygen scavenger dosing area, reducing the oxygen content in the internal return liquid flowing into the anoxic zone, reducing the activity of aerobic microorganisms in the activated sludge flowing back to the anaerobic zone, increasing and strengthening the activated sludge in the competing anoxic zone, and strengthening the denitrification reaction. At the same time, the sludge with reduced dissolved oxygen flows into the rear - end secondary sedimentation tank and undergoes advanced treatment, which can reduce the oxygen content in the advanced treatment process at the rear - end of the biochemical zone, facilitating the improvement of the denitrification effect of the rear - end filter. The oxygen scavenger is granular, with the main component being sulfite, and the other components being Ca(OH)2 and activated carbon.

[0040] Taking a sewage treatment plant in Ningyang County as an example, the water treatment capacity is Q = 20000m 3 / d, the residence time in the aerobic zone is 16h, the length of the aerobic zone is 370.8m, and the flow velocity of the sewage in the aerobic zone is 0.5m / s. Then the circulation times of the sewage within the entire residence time is 77.7 times. When the sewage in the anoxic zone enters the aerobic zone, it is diluted by more than 70 times the circulation flow rate. This process can withstand the impact load of water volume and water quality:

[0041] The designed scale of the first phase is 40,000 t / d, and the second phase is 20,000 t / d. The designed influent water quality is COD: 450mg / L, TN: 40mg / L. The first phase adopts a conventional oxidation ditch, and the second phase adopts a high - efficiency multi - cycle A2 / O process. Currently, the water volume is about 50,000 t / d, about 25,000 t / d in the first phase, and 25,000 t / d in the second phase. The influent COD is about 600 - 700mg / L, and TN is about 50mg / L. Under the condition that the influent water volume and water quality exceed the designed scale, the effluent COD of the high - efficiency multi - cycle A2 / O process is stable below 30mg / L, and the effluent TN is stable below 10mg / L. The COD removal rate reaches 95%, and the TN removal rate reaches 80%.

[0042] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0043] The embodiments described above are only for describing the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the spirit of the design of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An efficient multi-cycle integrated AAO treatment process, characterized in that: The device for an efficient multi-cycle integrated AAO treatment process includes an anaerobic zone, an anoxic zone, an aerobic zone I, an aerobic zone II, an aerobic zone III, and a water distribution zone; partition walls (3) and two oppositely arranged propellers (4) are respectively provided in the anoxic zone, the aerobic zone I, and the aerobic zone II. Guide walls (2) are respectively provided at both ends of the partition wall (3). The propellers (4) are arranged on both sides of the partition wall (3). The partition wall (3) in the anoxic zone divides the anoxic zone into anoxic zone I and anoxic zone II. The partition wall (3) in the aerobic zone I divides the aerobic zone I into aerobic zone I stage I and aerobic zone I stage II. The partition wall (3) in the aerobic zone II divides the aerobic zone II into aerobic zone II stage I and aerobic zone II stage II. Aeration devices are provided in the aerobic zone I, the aerobic zone II, and the aerobic zone III. A deoxidizer dosing area is provided at the end of the aerobic zone III. Deoxidizer is added from the deoxidizer dosing area, so that the oxygen content of the internal reflux liquid flowing into the anoxic zone is reduced. The main component of the deoxidizer is sulfite, and the other components are Ca(OH)2 and activated carbon. An efficient multi-cycle integrated AAO treatment process includes the following steps: Step 1: Anaerobic treatment, discharging the wastewater into the anaerobic zone for anoxic pretreatment. Step 2: Anoxic treatment, discharging the anaerobically treated sewage into the anoxic zone to cause denitrification and anaerobic phosphorus release reactions of the sewage. Step 3: Aerobic treatment, discharging the anoxically treated wastewater into the aerobic zone I and the aerobic zone II, and carrying out nitrification and aerobic phosphorus uptake treatment on the sewage in combination with the aeration device. Step 4: Sedimentation treatment, discharging the aerobically treated sewage into the double-layer sedimentation zone for sedimentation to obtain the treated sewage. The guide wall (2) in the aerobic zone II is a flexible guide wall. A flexible guide rail is provided below the flexible guide wall, and the flexible guide rail is driven by a waterproof motor. When the pollutant index in the anaerobic zone is low, the waterproof motor is started to straighten the flexible guide wall on the left side of the aerobic zone II, and the sewage directly bypasses the aerobic zone II and enters the aerobic zone III. At the same time, the propeller (4) in the aerobic zone II is turned off, and the aeration device in the aerobic zone II is adjusted to carry out micro-aeration.

2. The efficient multi-cycle integrated AAO treatment process according to claim 1, characterized in that: In the step 2, a carbon source dosing point is provided in the anoxic zone II, and a submersible camera is provided below the carbon source dosing point.

3. The efficient multi-cycle integrated AAO treatment process according to claim 1, characterized in that: The aerobic zone III and the anoxic zone II are connected through an internal reflux pump, and a valve and a flow meter are provided in the pipeline of the internal reflux pump.

4. The efficient multi-cycle integrated AAO treatment process according to claim 1, characterized in that: A nitrate nitrogen detector is provided at the water inlet end of the anaerobic zone. When the total nitrogen detected by the nitrate nitrogen detector at the water inlet end is higher than 45 mg / L, the nitrate nitrogen detector controls the aeration device in the aerobic zone I stage I to be turned off through the PLC controller, so that the aerobic zone I stage I is converted into an anoxic state.

5. The efficient multi-cycle integrated AAO treatment process according to claim 1, wherein: An NH3-N detector and a COD detector are provided at the water inlet end of the anaerobic zone. When the influent NH3-N is greater than 40 mg / L and the influent COD is less than 150 mg / L, the PLC controller controls the aeration device in the aerobic zone II stage I to be turned off, so that the aerobic zone II stage I is in an anoxic state, forming a two-stage AO process.

6. The efficient multi-cycle integrated AAO treatment process according to claim 1, characterized in that: A water distribution area and a water distribution splash wall (6) are provided between the double-layer sedimentation area and the aerobic three-zone in the fourth step, and a sludge pumping station is provided on one side of the double-layer sedimentation area.

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