Continuous flow AOA treatment device and treatment method for quickly starting short-range nitrification based on intermittent light strategy

Abstract

The application discloses a continuous flow AOA treatment device based on intermittent light strategy for rapid start-up of short-cut nitrification in the field of sewage biological technology, which comprises a raw sewage tank, an AOA reactor, a sedimentation tank and a side stream reactor. Sewage from the raw sewage tank enters the AOA reactor, and sequentially passes through an anaerobic zone, an aerobic zone and an anoxic zone along the water flow direction, and part of the sewage is shunted from the anaerobic zone to the side stream reactor; the anaerobic zone mainly carries out anaerobic phosphorus release and internal carbon source storage process, the aerobic zone carries out nitrification and aerobic phosphorus absorption, and the anoxic zone carries out endogenous denitrification; by adopting intermittent light in the side stream reactor, nitrite oxidizing bacteria are inhibited, ammonia oxidizing bacteria are enriched, the rapid start-up and long-term stability of short-cut nitrification of the AOA reactor are promoted, and the phosphorus removal efficiency of the process is ensured; the nitrite accumulation rate and the total nitrogen removal rate of the application are both stabilized at more than 80%, and the phosphorus removal efficiency can reach more than 95%, which provides a new technical approach for efficient sewage biological denitrification and phosphorus removal.

Description

Technical Field

[0001] This invention relates to the field of wastewater biological technology, and in particular to a continuous flow AOA treatment device and treatment method. Background Technology

[0002] Traditional nitrification / denitrification processes are commonly used in urban wastewater treatment plants in my country. These technologies suffer from two major drawbacks: first, the high aeration requirements of the nitrification stage lead to high energy consumption; second, the denitrification process requires the addition of external carbon sources, significantly increasing operating costs. In contrast, short-cut nitrification / denitrification technology, by controlling ammonia nitrogen oxidation at the nitrite stage, can theoretically save 40% of carbon source requirements and 25% of aeration energy consumption, demonstrating significant advantages in energy conservation and emission reduction. However, maintaining stable nitrite nitrogen accumulation in a continuous flow reactor (i.e., short-cut nitrification) remains a key bottleneck restricting the large-scale application of this technology.

[0003] To address this technological challenge, the novel anaerobic / aerobic / anoxic (AOA) process exhibits unique advantages. Compared to the traditional A²O process, AOA achieves two major breakthroughs through process restructuring: firstly, it eliminates the nitrification liquor recirculation step, simplifying system complexity; secondly, it utilizes endogenous carbon sources to drive denitrification, effectively alleviating the carbon source shortage problem in low C / N ratio wastewater treatment. The core of achieving efficient nitrogen removal in the AOA process lies in the precise regulation of the microbial community structure, namely, selectively inhibiting nitrite-oxidizing bacteria (NOB) while promoting the enrichment of ammonia-oxidizing bacteria (AOB). Current mainstream regulation strategies include: dissolved oxygen concentration control (0.5-1.5 mg / L), temperature gradient regulation (30-35℃), synergistic inhibition of free ammonia (FA) and free nitrite (FNA), and dynamic adjustment of sludge time (SRT).

[0004] In recent years, solar energy, as a clean and renewable energy source, has received widespread attention in the field of wastewater treatment, with applications encompassing photocatalytic oxidation and photo-assisted biological treatment. However, sunlight can significantly impact the microbial community in wastewater treatment systems, particularly inhibiting the metabolic activity of nitrifying bacteria. Studies have shown that the inhibitory effect of sunlight on nitrification is regulated by multiple factors, including light source type, light intensity, duration, spectral characteristics, and differences in the tolerance of microbial strains. Despite these complex factors, sunlight is still considered a promising means of short-cut nitrification control. Compared to conventional short-cut nitrification methods, this selective inhibition effect is particularly prominent in continuous flow AOA processes: polyphosphate-accumulating organisms (PAOs), as the main functional microbial community, exhibit light tolerance 2-3 orders of magnitude higher than nitrifying bacteria, ensuring that the system can maintain a phosphorus removal efficiency of over 90% under light-controlled conditions. This technical characteristic makes light control one of the few technologies that can simultaneously achieve short-cut nitrification and enhanced biological phosphorus removal.

[0005] To address the challenges of urban wastewater treatment with low C / N ratios and significant water quality fluctuations (such as large carbon source dosage, low start-up efficiency, and poor effluent stability), this study proposes an optimization strategy based on side-flow illumination regulation to achieve efficient and stable deep nitrogen and phosphorus removal from urban wastewater with low C / N ratios in a continuous flow AOA process. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a continuous flow AOA treatment device and method for rapidly starting short-cut nitrification based on an intermittent light strategy. This solves the problems of insufficient carbon source, difficulty in starting short-cut nitrification, and unattainable deep nitrogen and phosphorus removal in current continuous flow treatment of domestic sewage with low C / N ratios.

[0007] The objective of this invention is achieved as follows: a continuous flow AOA treatment device for rapid start-up of short-range nitrification based on an intermittent illumination strategy, comprising:

[0008] The inlet tank is used to store domestic sewage to be treated and send it to the continuous flow AOA reactor;

[0009] The continuous flow AOA reactor includes an anaerobic zone, an aerobic zone, and an anoxic zone;

[0010] In the anaerobic zone, PAOs and GAOs absorb organic matter in wastewater and convert it into polyhydroxy fatty acid esters (PHA), which are stored in the cells to obtain a mud-water mixture. The mud-water mixture then enters the aerobic zone and the side-flow reactor.

[0011] In the aerobic zone, AOB removes ammonia nitrogen (NH4) from the wastewater. + -N) is oxidized to nitrite nitrogen (NO2). - -N), and then NOB further reduced NO2 - -N is oxidized to nitrate nitrogen (NO3⁻-N); PAOs consume PHA and absorb excess phosphorus; PAOs consume PHA and absorb excess phosphorus. The side-flow reactor inhibits the growth of NOB and promotes the enrichment of AOB by precisely controlling the light intensity, while not affecting the metabolic activity of PAOs. The mud-water mixture from the aerobic zone and the side-flow reactor enters the anoxic zone.

[0012] In the anoxic zone, PAOs and GAOs utilize stored PHA as an endogenous carbon source and residual NO2⁻-N and NO3⁻-N in the wastewater as electron acceptors to carry out endogenous denitrification and phosphorus removal reactions, thereby completing the deep denitrification and phosphorus removal treatment of domestic sewage.

[0013] The secondary sedimentation tank is connected to the continuous flow AOA reactor through the effluent pipe. The bottom sludge is returned to the anaerobic zone, and the remaining sludge is periodically discharged from the system. The treated effluent is discharged normally.

[0014] The side-flow reactor, connected to the anaerobic zone, cultivates short-range nitrifying bacteria in the mud-water mixture through intermittent light and aeration, and then returns it to the anoxic zone.

[0015] Furthermore, the continuous flow AOA reactor is divided into an anaerobic zone, an aerobic zone, and an anoxic zone from inlet to outlet. Each zone is separated by a baffle plate, and the flow between the zones is achieved through overflow from the baffle plate. Each zone is equipped with a stirring device, and the aerobic zone is equipped with an aeration assembly.

[0016] Furthermore, each of the anaerobic zone, aerobic zone, and anoxic zone is provided with multiple compartments, which are separated by insert plates, and adjacent compartments are connected by a water passage method that is arranged vertically and vertically.

[0017] Furthermore, the aeration assembly includes an aeration pump, which supplies air to the aeration discs via aeration pipes, and each aeration disc is equipped with a rotor flow meter for precisely adjusting the aeration volume.

[0018] Furthermore, the sludge in the sludge hopper at the bottom of the secondary sedimentation tank is returned to the anaerobic zone by a sludge return pump, and the remaining sludge is periodically discharged from the system through a remaining sludge pipe. The effluent from the secondary sedimentation tank is discharged through an effluent pipe.

[0019] Furthermore, the side-flow reactor includes a sludge discharge peristaltic pump, LED lamps, an aeration device, and a stirrer. Short-range nitrifying bacteria are cultivated and enriched through intermittent lighting and aeration, and then returned to the anoxic zone of the continuous flow AOA reactor via the sludge discharge peristaltic pump.

[0020] A continuous-flow AOA treatment method for rapid initiation of short-range nitrification based on an intermittent illumination strategy includes the following steps:

[0021] 1) Start-up of the AOA process;

[0022] 2) Start-up of short-cut nitrification in a side-flow reactor;

[0023] 3) Start-up and stabilization of short-cut nitrification in the AOA reactor.

[0024] Furthermore, step 1) specifically includes:

[0025] 1-1) After transferring the sludge to the AOA reactor, the initial sludge concentration should be controlled at 3000~4500 mg / L;

[0026] 1-2) The dissolved oxygen in the aerobic zone gradually increases and is controlled within the range of 0.8~1.5 mg / L. An online dissolved oxygen probe is used to adjust the dissolved oxygen in conjunction with the aeration components.

[0027] 1-3) The sludge from the secondary sedimentation tank is returned to the anaerobic zone via a peristaltic pump, with the return ratio set at 100%. The hydraulic set retention time is maintained by dynamically adjusting the influent flow rate and return rate, while the sludge age is controlled within the set time by the settled sludge discharged from the secondary sedimentation tank.

[0028] 1-4) Monitor the effluent quality of the secondary sedimentation tank daily. When the chemical oxygen demand concentration is consistently below 50 mg / L, total phosphorus below 1.0 mg / L, and total nitrogen below 25 mg / L, and the fluctuation range is less than ±10% for a continuous set time, the AOA process is considered to have started successfully.

[0029] Furthermore, step 2) specifically includes:

[0030] 2-1) The sludge-water mixture drawn from the anaerobic zone of the AOA reactor continuously flows into the side-flow reactor. The side-flow reactor adopts a periodic light-dark environment to closely approximate the actual light frequency of day and night alternation. The light intensity is precisely controlled by an adjustable LED light source, with the light intensity between 360 and 480 μmol / m² / s. The sludge concentration in the side-flow reactor is maintained at 3000 to 4500 mg / L.

[0031] 2-2) After the mud-water mixture enters the side-flow reactor, it successively undergoes anaerobic stirring, aeration with dissolved oxygen controlled at 0.5~1.0 mg / L, and anoxic stirring. The anaerobic and aerobic stages are carried out under light conditions. Light inhibits the metabolic activity of nitrite-oxidizing bacteria and promotes the enrichment of ammonia-oxidizing bacteria to achieve phosphorus uptake. The anoxic stage is set with light exposure before the stage and darkness after the stage to enhance the endogenous denitrification nitrogen removal by polyphosphate-accumulating bacteria.

[0032] 2-3) The side-flow reactor is operated continuously until the nitrite accumulation rate reaches more than 80% at the end of the aerobic stage, and the set time is maintained. This indicates that the short-cut nitrification of the side-flow reactor has been initially successfully started and the next stage can begin.

[0033] Furthermore, step 3) specifically includes:

[0034] 3-1) After the anoxic stage of the side-flow reactor is completed, all the mud-water mixture flows to the anoxic zone of the AOA reactor; the side-flow reactor is allowed to stand until it is started by light, and fresh mud-water is drawn from the AOA anaerobic zone to form a closed-loop side-flow treatment system.

[0035] 3-2) The dissolved oxygen concentration in the aerobic zone is reduced to 0.8~1.5 mg / L. The sludge age is increased to 20 days through the sedimentation sludge discharged from the secondary sedimentation tank. The sludge-water mixture returned to the anoxic zone carries the functional bacteria acclimated by the side flow system, which enhances the efficiency of short-cut nitrification-denitrification in the main system. When the nitrite accumulation rate in the effluent of the aerobic zone is ≥80% and is stably maintained for the set time, the short-cut nitrification is considered to have started successfully.

[0036] 3-3) In the later stage of system operation, the lighting method in the side flow reactor was switched from LED lights to natural light, and the opening frequency of the side flow reactor was gradually reduced from once a day to once a week in order to maintain the short-cut nitrification performance of the AOA reactor.

[0037] 3-4) After continuous long-term operation, the effluent quality of the AOA reactor stabilized at COD concentration ≤50mg / L and NH4+ concentration ≤50mg / L. + The system is considered to have reached a stable state when the concentration of -N is ≤5mg / L, the concentration of TN is ≤15mg / L, and the concentration of TP is ≤0.5mg / L.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1) This invention adopts the AOA operation mode, which eliminates the traditional nitrification liquor recirculation link and enhances the uptake and storage of carbon sources from raw water by PAOs and GAOs in the anaerobic zone. This design not only simplifies the process flow, but also makes more efficient use of organic carbon sources in wastewater and reduces carbon source waste. It is especially suitable for the treatment of wastewater with low C / N ratio, effectively improving carbon source distribution efficiency and reducing system operating energy consumption.

[0040] 2) This invention selectively inhibits NOB activity and promotes AOB enrichment by introducing a specific light strategy into the side-flow reactor, thereby achieving efficient short-cut nitrification in the AOA process. By intermittently operating the side-flow reactor, the advantages of short-cut nitrification can be maintained for a long time, significantly reducing aeration energy consumption while improving nitrogen and phosphorus removal efficiency;

[0041] 3) Compared with traditional chemical inhibition or temperature control methods, the light control strategy has the advantages of being economical, efficient, easy to operate and without the risk of secondary pollution. At the same time, light of a specific wavelength can stimulate the metabolic activity of PAOs, improve their phosphorus uptake capacity, and further enhance the biological phosphorus removal effect of the system. Therefore, this invention can achieve efficient nitrogen and phosphorus removal simultaneously under low energy consumption conditions, and has broad prospects for promotion and application. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the device structure of the present invention.

[0044] Figure 2This is a graph showing the changes of various indicators over time during the short-cut nitrification start-up process of the AOA reactor.

[0045] Figure 3 This is a diagram showing the changes in microorganisms before and after the start-up of short-cut nitrification in an AOA reactor.

[0046] In the diagram, 1 is the inlet tank, 1-1 is the inlet pipe, 1-2 is the inlet pump, 2 is the AOA reactor, 2-1~2-3 are anaerobic compartments, 2-4~2-6 are aerobic compartments, 2-7~2-11 are anoxic compartments, 2-12 is the outlet pipe, 2-13 is the aeration pump, 2-13-1 is the aeration pipe, 2-13-2 is the aeration disc, 2-13-3 is the rotor flow meter, 2-14 is the stirring device, 2-15 is the anaerobic sludge discharge peristaltic pump, 3 is the secondary sedimentation tank, 3-1 is the sludge return pump, 3-2 is the excess sludge pipe, 3-3 is the drain pipe, 4 is the side flow reactor, 4-1 is the sludge discharge peristaltic pump, 4-2 is the LED lamp, 4-3 is the aeration device, and 4-4 is the stirrer. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] like Figure 1 The continuous flow AOA treatment device shown is based on an intermittent light strategy for rapid start-up of short-cut nitrification and includes an influent tank 1, a continuous flow AOA reactor 2, a secondary sedimentation tank 3, and a side-flow reactor 4.

[0050] The continuous flow AOA reactor 2 comprises 11 compartments, sequentially divided into three anaerobic compartments (2-1, 2-2, 2-3), three aerobic compartments (2-4, 2-5, 2-6), and five anoxic compartments (2-7, 2-8, 2-9, 2-10, 2-11) according to the water flow direction. Each compartment is separated by movable baffles, and adjacent compartments are connected by staggered water flow to prevent backflow and short-circuiting. Water flows from the top via overflow and from the bottom via water passages at the bottom of the movable baffles. The inlet tank 1 delivers raw water to the first anaerobic compartment 2-1 of the AOA reactor 2 via inlet pipe 1-1 and inlet pump 1-2, and then flows sequentially through each functional zone. The aeration component in the aerobic zone uses aeration pump 2-13, which delivers water through aeration pipe 2-13-1 and aeration pump 2-13-1. Air plate 2-13-2 supplies air to each aerobic compartment, and all aeration plates are equipped with rotor flowmeters 2-13-3 to precisely control the air volume; each compartment is equipped with an independent stirring device 2-14 to ensure uniform mixing; the eleventh compartment, the anoxic zone 2-11, is connected to the secondary sedimentation tank 3 through the effluent pipe 2-12. The sludge in the sludge hopper of the secondary sedimentation tank 3 is returned to the first compartment 2-1 of the anaerobic zone through the sludge return pump 3-1. The remaining sludge in the secondary sedimentation tank is discharged through the remaining sludge pipe 3-2, and the effluent from the secondary sedimentation tank is discharged through the drain pipe 3-3; the second compartment 2-2 of the anaerobic zone is connected to the side flow reactor 4, and the sludge-water mixture flows to the side flow reactor 4 through the peristaltic pump 2-14; the side flow reactor 4 is equipped with a sludge discharge peristaltic pump 4-1, an LED lamp 4-2, an aeration device 4-3, and a stirrer 4-4. The mud-water mixture cultivated in the side-flow reactor is eventually sent to the first compartment 2-7 of the anoxic zone of the AOA reactor via the sludge discharge peristaltic pump 4-1, so as to achieve continuous replenishment of the side-flow functional microbial community and enhancement of the main reaction system.

[0051] The treatment principle of urban domestic sewage in this device is as follows:

[0052] First, domestic sewage enters the anaerobic chambers 2-1 to 2-3 from the inlet tank through the inlet pump 1-1. Under anaerobic conditions, PAOs and GAOs absorb the organic matter in the sewage and convert it into PHA, which is then stored in the cells.

[0053] Subsequently, the sludge-water mixture enters the aerobic zone and side-flow reactor 4. In the aerobic zone, AOB oxidizes NH4⁺-N in the wastewater to NO2⁻-N, and NOB further oxidizes NO2⁻-N to NO3⁻-N; PAOs consume PHA and excessively absorb phosphorus. Side-flow reactor 4 effectively inhibits NOB growth and promotes AOB enrichment by precisely controlling light intensity, without affecting the metabolic activity of PAOs.

[0054] Finally, the sludge-water mixture from the aerobic zone and the side-flow reactor 4 enters the anoxic zone. PAOs and GAOs utilize the stored PHA as an endogenous carbon source and the residual NO2⁻-N and NO3⁻-N in the wastewater as electron acceptors to carry out endogenous denitrification and phosphorus removal reactions, thereby achieving deep nitrogen and phosphorus removal treatment of urban domestic wastewater.

[0055] Example 2

[0056] A continuous flow AOA treatment method based on intermittent light strategy for rapid start-up of short-cut nitrification was proposed, using domestic sewage from a residential community as the treatment target. The specific water quality during operation was as follows: COD concentration 197~252 mg / L, NH4+ concentration... + -N concentration is 51~70 mg / L, NO3 - -N concentration ≤ 0.5 mg / L, NO2 - -N concentration ≤0.2mg / L, influent phosphorus concentration 5~8mg / L. A light-based modified AOA process achieves deep nitrogen and phosphorus removal from domestic wastewater with a low C / N ratio. The reactor has an effective volume of 52.3 L, divided into 11 compartments; the secondary sedimentation tank has an effective volume of 16.5 L; and the side-flow reactor has an effective volume of 8 L. All are made of acrylic sheets and include the following steps:

[0057] Step 1) Start-up of the AOA process.

[0058] a) The experiment used urban wastewater treatment plant A 2 The residual sludge from the secondary sedimentation tank of the O process is used as an inoculum source. This sludge is rich in bacteria such as AOB, NOB, PAOs, and GAOs, which have the function of nitrification and denitrification throughout the process. After the sludge is transferred to AOA reactor 2, the initial sludge concentration is controlled at 3000~4500 mg / L.

[0059] b) In the aerobic zone 2-4 to 2-6, the DO gradually increases and is controlled within the range of 0.8 to 1.5 mg / L. An online DO probe is used to adjust the DO level in conjunction with the variable frequency aeration device.

[0060] c) The sludge from secondary sedimentation tank 3 is returned to the first compartment 2-1 of the anaerobic zone via peristaltic pump 3-1, with a return ratio set to 100% to ensure stable biomass in the reactor. The system maintains a high-response time (HRT) of 10 h by dynamically adjusting the influent flow rate and return rate, and maintains a stable sedimentation time (SRT) of approximately 15 days by discharging 1.3 L of settled sludge from secondary sedimentation tank 3.

[0061] d) Monitor the effluent quality of the secondary sedimentation tank daily. When the COD concentration is consistently below 50 mg / L, the TP concentration is below 1 mg / L, and the TN concentration is below 25 mg / L, and the fluctuation range is less than ±10% for 15 consecutive days, the AOA process is considered to have started successfully. Afterward, the system enters the side-flow coupling enhancement stage to further improve nitrogen and phosphorus removal efficiency.

[0062] 2) Start-up of short-cut nitrification in a side-flow reactor.

[0063] a) The sludge-water mixture drawn from the second compartment 2-2 of the anaerobic zone of the AOA reactor flows into the side-flow reactor 4. The side-flow reactor 4 adopts a periodic environment of 12h light-12h darkness to closely approximate the actual day-night light cycle. The light intensity is precisely controlled by an adjustable LED light source and maintained within the range of 360–480 μmol / m² / s, while the sludge concentration is maintained at 3000–4500 mg / L.

[0064] b) After the mud-water mixture enters the side-flow reactor 4, it undergoes a 4-hour anaerobic stirring phase, a 4-hour aeration phase with DO=0.5~1.0 mg / L, and a 6.5-hour anoxic stirring phase. Both the anaerobic and aerobic phases are carried out under light conditions to selectively inhibit NOB metabolic activity and promote AOB enrichment and phosphorus uptake. The anoxic phase is carried out under light for the first 4 hours and under darkness for the last 2.5 hours to enhance PAOs-dominated endogenous denitrification.

[0065] c) Side-flow reactor 4 is operated continuously until the nitrite accumulation rate (NAR) in the last compartment 2-6 of the aerobic zone reaches more than 80% and is maintained for more than 7 days. This indicates that the initial short-cut nitrification of side-flow reactor 4 has been successfully started, and the system then enters the subsequent operation stage.

[0066] 3) Start-up and stabilization of short-cut nitrification in the AOA reactor.

[0067] a) After the anoxic stage of the side-flow reactor 4, all the mud-water mixture flows to the first compartment 2-7 of the anoxic zone of the AOA reactor 2 via peristaltic pump 4-1. When the side-flow reactor 4 is left to stand until the next round of light exposure, fresh mud-water is drawn from the second compartment 2-2 of the anaerobic zone by peristaltic pump 2-15, forming a closed-loop side-flow treatment system to continuously replenish the dominant functional bacteria.

[0068] b) In the aerobic zone 2-4 to 2-6 of the AOA reactor, the DO concentration is reduced to 0.8-1.5 mg / L. By discharging 0.8 L of settled sludge from the secondary settling tank 3, the SRT (Sedimentation Time) is increased to 20 days. The sludge-water mixture returned to the first compartment 2-7 of the anoxic zone carries the functional bacteria acclimated by the sideflow system, enhancing the efficiency of short-cut nitrification-denitrification in the main system. When the NAR (Natural Arrival Rate) in the effluent from the last compartment 2-6 of the aerobic zone is ≥80% and remains stable for more than 15 days, the short-cut nitrification is considered to have started successfully.

[0069] c) In the later stages of system operation, the lighting method in side-flow reactor 4 was switched from LED lamp 4-2 to natural light. Simultaneously, the operating frequency of the side-flow reactor was gradually reduced from once a day to once a week to maintain the short-cut nitrification performance of the AOA system. Under long-term continuous operation of the reactor, the effluent quality of secondary sedimentation tank 3-4 remained stable at COD concentration ≤50mg / L and NH4+ ≤50mg / L. + When the nitrogen (N) concentration is ≤5 mg / L, the total nitrogen (TN) concentration is ≤15 mg / L, and the total phosphorus (TP) concentration is ≤0.5 mg / L, and the system meets the national Class A emission standard, it is considered to have reached a stable state and will continue to operate within this standard range. Ultimately, the AOA process can achieve efficient utilization of carbon sources, a significant reduction in aeration energy consumption, and deep nitrogen and phosphorus removal from domestic sewage, demonstrating significant engineering application value.

[0070] Depend on Figure 2 It can be seen that in the initial stage of operation (1-15 days), the inoculation A of the AOA process... 2 After operational adjustments, the ammonia oxidation efficiency of the O2 sludge significantly improved, with an ammonia nitrogen removal rate of 92%±3%. However, the nitrogen oxidative stress (NAR) remained below 5%, indicating that the system still primarily relied on full-process nitrification and denitrification. At this point, the total nitrogen (TN) removal efficiency stabilized at 65%±3%, and the effluent TN concentration remained between 25-30 mg / L. After 60 days of sludge acclimatization (15-75 days), the system entered a stable operating phase, with the effluent TN concentration decreasing to below 25 mg / L and the ammonia nitrogen removal rate reaching 97%±2%, confirming the AOA process's excellent ability to maintain full-process nitrification. On day 75, the introduction of side-flow light regulation significantly altered the system's nitrogen metabolism pathway. During the transition phase from day 75 to 105, effluent NO2... - The -N concentration gradually increased from an initial 0.5 mg / L to 12.8 mg / L, while the NO3 concentration... - -N concentration decreased from 18.2±2.5 mg / L to below 1.5±1.1 mg / L, and NAR increased from <5% to 90%±3%, marking the successful initiation of short-cut nitrification. During this stage, TN removal efficiency improved to 83%±2%, an 18% increase compared to before light exposure, and the effluent TN concentration stabilized below 15 mg / L. Notably, during the process transition period (75-90 days), the system experienced periodic fluctuations in phosphorus removal efficiency (from 95% to 82%), which may be related to the metabolic reorganization of PAOs in the initial stage of light regulation. However, phosphorus removal performance recovered rapidly after 90 days, and the final effluent TP concentration stabilized at 0.3±0.1 mg / L, with a removal rate of 97%±2%, confirming the strong adaptability of PAOs to light stress.

[0071] High-throughput sequencing results show that ( Figure 3 Lateral light regulation induced changes in the nitrifying bacteria community. Figure 3 It can be seen that at the genus level, NitrospiraThe population abundance of (typical NOB) dropped sharply from an initial 2.19% to 0.12%. CandidatusNitrotoga The population abundance of (low-temperature resistant NOB) also decreased from 1.05% to 0.60%. Nitrosomonas The abundance of dominant AOBs significantly increased from 1.12% to 3.25%, indicating that light regulation achieved targeted enrichment of nitrifying bacteria through metabolic dominance selection. PAOs were not significantly affected by light. CandidatusAccumulibacter The population abundance of the species remained stable at around 6.51%, which promoted the denitrification and phosphorus removal process of the AOA process.

[0072] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A continuous flow AOA treatment device for rapid start-up of short-range nitrification based on an intermittent illumination strategy, characterized in that, include: The inlet tank (1) is used to store domestic sewage to be treated and send it to the continuous flow AOA reactor; The continuous flow AOA reactor (2) includes an anaerobic zone, an aerobic zone and an anoxic zone; In the anaerobic zone, polyphosphate bacteria and polysaccharide bacteria absorb organic matter in wastewater and convert it into polyhydroxy fatty acid esters, which are stored in the cells to obtain mud-water mixture. The mud-water mixture enters the aerobic zone and the side-flow reactor (4). In the aerobic zone, ammonia oxidizing bacteria oxidize ammonia nitrogen in wastewater into nitrite nitrogen. Then, nitrite oxidizing bacteria further oxidize nitrite nitrogen into nitrate nitrogen. Polyphosphate-accumulating bacteria consume polyhydroxy fatty acid esters and absorb excess phosphorus. The side-flow reactor (4) inhibits the growth of nitrite oxidizing bacteria and promotes the enrichment of ammonia oxidizing bacteria by precisely controlling the light intensity, while not affecting the metabolic activity of polyphosphate-accumulating bacteria. The sludge-water mixture of the aerobic zone and the side-flow reactor (4) enters the anoxic zone. In the anoxic zone, polyphosphate-accumulating bacteria and polysaccharide-accumulating bacteria use stored polyhydroxy fatty acid esters as endogenous carbon sources and residual nitrite and nitrate nitrogen in sewage as electron acceptors to carry out endogenous denitrification and phosphorus removal reactions, thus completing the deep denitrification and phosphorus removal treatment of domestic sewage. The secondary sedimentation tank (3) is connected to the continuous flow AOA reactor (2) through the effluent pipe (2-12). The bottom sludge is returned to the anaerobic zone, and the remaining sludge is discharged from the system periodically. The treated effluent is discharged normally. The side-flow reactor (4) is connected to the anaerobic zone. The mud-water mixture is cultured and enriched with short-range nitrifying bacteria through intermittent light and aeration, and then sent back to the anoxic zone.

2. The continuous flow AOA treatment device for rapid start-up of short-range nitrification based on intermittent illumination strategy according to claim 1, characterized in that, The continuous flow AOA reactor (2) is divided into an anaerobic zone, an aerobic zone and an anoxic zone from inlet to outlet. Each zone is separated by a baffle plate, and the flow between each zone is carried out by the overflow of the baffle plate. Each zone is equipped with a stirring device (2-14), and the aerobic zone is equipped with an aeration component.

3. The continuous flow AOA treatment device for rapid start-up of short-range nitrification based on intermittent illumination strategy according to claim 2, characterized in that, The anaerobic zone, aerobic zone, and anoxic zone each have multiple compartments, which are separated by insert plates and connected by an alternating water flow method.

4. The continuous flow AOA treatment device for rapid start-up of short-range nitrification based on intermittent illumination strategy according to claim 2, characterized in that, The aeration assembly includes an aeration pump (2-13), which supplies air to the aeration discs (2-13-2) via an aeration pipe (2-13-1). Each aeration disc (2-13-2) is equipped with a rotor flow meter (2-13-3) for precise adjustment of the aeration volume.

5. The continuous flow AOA treatment device based on intermittent illumination strategy for rapid start-up of short-range nitrification according to any one of claims 1-4, characterized in that, The sludge in the sludge hopper at the bottom of the secondary sedimentation tank (3) is returned to the anaerobic zone by the sludge return pump (3-1), and the remaining sludge is periodically discharged from the system through the remaining sludge pipe (3-2). The effluent from the secondary sedimentation tank (3) is discharged through the drain pipe (3-3).

6. The continuous flow AOA treatment device based on intermittent illumination strategy for rapid start-up of short-range nitrification according to any one of claims 1-4, characterized in that, The side-flow reactor (4) includes a sludge discharge peristaltic pump (4-1), an LED lamp (4-2), an aeration device (4-3), and a stirrer (4-4). It cultivates and enriches short-range nitrifying bacteria through intermittent light and aeration, and then returns them to the anoxic zone of the continuous flow AOA reactor via the sludge discharge peristaltic pump (4-1).

7. A continuous-flow AOA treatment method for rapid initiation of short-range nitrification based on an intermittent illumination strategy, employing the apparatus as described in any one of claims 1-6, characterized in that, Includes the following steps: 1) Start-up of the AOA process; 2) Start-up of short-cut nitrification in the side-flow reactor (4); 3) Start-up and stabilization of short-cut nitrification in the AOA reactor.

8. The continuous flow AOA treatment method for rapid initiation of short-range nitrification based on intermittent illumination strategy according to claim 7, characterized in that, Step 1) specifically includes: 1-1) After transferring the sludge to the AOA reactor, the initial sludge concentration is controlled at 3000~4500 mg / L; 1-2) The dissolved oxygen in the aerobic zone gradually increases and is controlled within the range of 0.8~1.5 mg / L. An online dissolved oxygen probe is used to adjust the dissolved oxygen in conjunction with the aeration components. 1-3) The sludge in the secondary sedimentation tank (3) is returned to the anaerobic zone by a peristaltic pump, and the return ratio is set to 100%. The hydraulic set residence time is maintained by dynamically adjusting the influent flow rate and return rate. At the same time, the sludge age is controlled within the set time by the settled sludge discharged from the secondary sedimentation tank (3). 1-4) Monitor the effluent quality of the secondary sedimentation tank (3) daily. When the chemical oxygen demand concentration is consistently below 50 mg / L, total phosphorus is below 1.0 mg / L, and total nitrogen is below 25 mg / L, and the fluctuation range of the continuous set time is less than ±10%, it is determined that the AOA process has been successfully started.

9. The continuous flow AOA treatment method for rapid initiation of short-range nitrification based on intermittent illumination strategy according to claim 8, characterized in that, Step 2) specifically includes: 2-1) The sludge-water mixture drawn from the anaerobic zone of the AOA reactor continuously flows into the side-flow reactor (4). The side-flow reactor (4) adopts a periodic light-dark environment to closely approximate the actual light frequency of day and night alternation. The light intensity is precisely controlled by an adjustable LED light source, with the light intensity between 360 and 480 μmol / m² / s. The sludge concentration in the side-flow reactor (4) is maintained at 3000 to 4500 mg / L. 2-2) After the mud-water mixture enters the side-flow reactor (4), it undergoes anaerobic stirring, aeration with dissolved oxygen controlled at 0.5~1.0 mg / L, and anoxic stirring in sequence. The anaerobic and aerobic stages are carried out under light conditions. The light inhibits the metabolic activity of nitrite-oxidizing bacteria, promotes the enrichment of ammonia-oxidizing bacteria, and achieves phosphorus uptake. The time before the anoxic stage is set to light and the time after the stage is set to darkness to enhance the endogenous denitrification of polyphosphate-accumulating bacteria. 2-3) The side-flow reactor (4) runs continuously until the nitrite accumulation rate reaches more than 80% at the end of the aerobic stage, and the set time is continuously and stably set. This means that the short-range nitrification of the side-flow reactor (4) is considered to have been initially successfully started and enters the next stage.

10. The continuous-flow AOA treatment method for rapid initiation of short-range nitrification based on intermittent illumination strategy according to claim 9, characterized in that, Step 3) specifically includes: 3-1) After the anoxic stage of the side-flow reactor (4) is completed, all the mud-water mixture flows to the anoxic zone of the AOA reactor; the side-flow reactor (4) is left to stand until it is started by light, and fresh mud-water is drawn from the AOA anaerobic zone to form a closed-loop side-flow treatment system. 3-2) The dissolved oxygen concentration in the aerobic zone is reduced to 0.8~1.5 mg / L. The sludge age is increased to 20 days by the sedimentation sludge discharged from the secondary sedimentation tank (3). The sludge-water mixture returned to the anoxic zone carries the functional bacteria acclimated by the side flow system, which enhances the efficiency of short-cut nitrification-denitrification in the main system. When the nitrite accumulation rate in the effluent of the aerobic zone is ≥80% and is stably maintained for the set time, the short-cut nitrification is considered to have started successfully. 3-3) In the later stage of system operation, the lighting mode in the side flow reactor (4) was changed from LED lights to natural light. At the same time, the opening frequency of the side flow reactor (4) was gradually reduced from once a day to once a week in order to maintain the short-cut nitrification performance of the AOA reactor. 3-4) After the AOA reactor has been running continuously for a long time, the effluent quality of the secondary sedimentation tank (3) is stable within the range of chemical oxygen demand concentration ≤50mg / L, ammonia nitrogen concentration ≤5mg / L, total nitrogen concentration ≤15mg / L, and total phosphorus concentration ≤0.5 mg / L. The system is considered to have reached a stable state.

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