Treatment method and system for nitrogen and phosphorus removal of sewage

Abstract

The invention relates to the technical field of sewage treatment, and discloses a sewage nitrogen and phosphorus removal treatment method based on pre-MABR (Membrane Aerated Baffled Reactor) carbon source shunting aiming at the problem of carbon source competition in a low-carbon-nitrogen-ratio sewage treatment process. A membrane aeration biological membrane reaction unit is arranged behind an anaerobic section in front and is controlled to operate in a micro-aerobic range of 0.3-0.7 mg / L; meanwhile, the concentration ratio of nitrate nitrogen to phosphate in effluent is stabilized at 3.0-5.0, so that the membrane aeration biological membrane reaction unit becomes an intelligent carbon source diverter. In the unit, residual organic matters are preferentially used for pre-denitrification, and an internal carbon source in the phosphorus-accumulating bacteria is completely protected, so that the unit is specially used for subsequent efficient phosphorus uptake and endogenous denitrification. According to the invention, the conversion from carbon source competition and internal circulation of thalli to carbon source front shunting according to functions is realized, the method is independent of special strains, and the method has the outstanding advantages of high efficiency, strong stability, low energy consumption and good impact resistance.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, specifically to a method and system for nitrogen and phosphorus removal from wastewater, which is particularly suitable for treating urban domestic sewage and industrial wastewater with low carbon-to-nitrogen ratios, achieving efficient, stable, and low-carbon removal of nitrogen and phosphorus nutrients. Background Technology

[0002] With increasingly stringent water quality standards, wastewater treatment has shifted its focus to the deep removal of nitrogen and phosphorus nutrients. Traditional biological nitrogen and phosphorus removal processes (such as A...) 2 When treating wastewater with low carbon-to-nitrogen ratios (COD / TN < 5, usually referring to BOD5 / TN < 4), a fundamental contradiction arises: the limited biodegradable organic matter (carbon source) in the wastewater must simultaneously meet the demands of heterotrophic denitrification and anaerobic phosphorus release / synthetic internal carbon source (PHA) by polyphosphate-accumulating organisms (PAOs), leading to fierce competition between the two. To ensure denitrification efficiency, external carbon sources such as sodium acetate and methanol are often added, which not only significantly increases operating costs and carbon emissions but may also lead to increased sludge production and more complex system control.

[0003] To address the carbon source dilemma, the industry has developed a technology route centered on denitrification for phosphorus removal. For example, existing technologies disclose a short-process nitrogen and phosphorus removal system and method for wastewater with a low carbon-to-nitrogen ratio. This process utilizes denitrifying polyphosphate-accumulating bacteria (DPAOs) as "activated carbon source carriers," storing the carbon source in the form of PHA within the bacteria during the anaerobic stage. Denitrification and phosphorus uptake are simultaneously completed in the subsequent anoxic stage, and finally, deep nitrogen removal is achieved through a MABR (Multi-Anaerobic Bioreactor). This technology represents an important current research direction; however, its efficient and stable operation highly depends on the enrichment and metabolic activity of DPAOs, a special functional bacterial community. DPAOs have low abundance in natural systems and conventional activated sludge, require long enrichment and cultivation cycles, and are extremely sensitive to environmental factors such as dissolved oxygen and nitrate concentrations. This results in slow process start-up, high requirements for long-term operational stability, and potential risks to engineering-scale application.

[0004] Membrane-aerated biofilm reactor (MABR) technology has attracted much attention due to its bubble-free aeration (oxygen transfer efficiency >80%) and ability to achieve simultaneous nitrification and denitrification (SND). However, in existing technologies, MABRs are mostly simply "embedded" in traditional processes, such as as aerobic units for enhanced nitrification or as units providing anoxic / microaerobic environments. In particular, when MABRs are placed at the end of the process or as the main reactor, their function is limited to "deep treatment units" or "specialized microbial community reaction units," failing to reconstruct carbon source flow and microbial metabolic pathways at the system level. Their technological potential in regulating carbon source distribution at the source has not yet been effectively realized.

[0005] In summary, current technical approaches to solving nitrogen and phosphorus removal in wastewater with low carbon-to-nitrogen ratios mainly follow two modes: one is based on traditional A... 2 There are two main models for nitrogen and phosphorus removal: one is the "carbon source spatial competition" model, represented by / O; the other is the "carbon source in vivo circulation" model. The former has an inherent contradiction in carbon source allocation, while the latter is constrained by the engineering application bottlenecks of special bacterial species. Therefore, there is an urgent need in this field for a new nitrogen and phosphorus removal method and system that can break away from the above models, does not rely on difficult-to-cultivate special bacterial species, and can fully utilize the potential of MABR technology, so as to achieve efficient, stable, energy-saving, and easy-to-engineer management treatment of wastewater with low carbon-to-nitrogen ratio. Summary of the Invention

[0006] To address the problems of intense carbon source competition, over-reliance on specific and unstable denitrifying polyphosphate-accumulating bacteria (DPAOs), limited functional positioning of MABRs, and insufficient system stability in existing technologies, this application aims to provide a wastewater nitrogen and phosphorus removal method and system based on pre-MABR carbon source diversion. This application "repositions" the MABR within the process flow, transforming it from a traditional "end-of-pipe deep treatment unit" or "main specialized microbial reactor" into a "pre-carbon source intelligent diversion and control hub" placed after the anaerobic stage. By creating and precisely controlling a unique microaerobic environment, carbon sources in wastewater are guided to undergo physicochemical "diversion" according to a predetermined functional pathway before entering the traditional competitive stages. This constructs a novel and highly efficient pollutant synergistic removal pathway based on a conventional and stable microbial community (aerobic polyphosphate-accumulating bacteria and common heterotrophic denitrifying bacteria), thereby realizing a shift from traditional "carbon source competition" or "intramicrobial circulation" to "pre-functional carbon source diversion."

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] On the one hand, this application provides a method for treating wastewater to remove nitrogen and phosphorus, comprising the following steps: S1. Anaerobic phosphorus release and carbon storage: Wastewater is mixed with polyphosphate-accumulating bacteria under strict anaerobic conditions, wherein dissolved oxygen is ≤0.2mg / L. This allows polyphosphate-accumulating bacteria in the sludge to absorb readily biodegradable organic matter in the wastewater and synthesize internal carbon sources, while simultaneously releasing phosphates. S2. Pre-treatment with micro-oxygen diversion in the pre-aerated biofilm reactor: The effluent from step S1 is introduced into the pre-aerated biofilm reactor. By regulating the reactor operation, the following conditions are simultaneously met: the dissolved oxygen in the bulk solution within the pre-aerated biofilm reactor operates within a micro-oxygen range of 0.3 mg / L to 0.7 mg / L; the ratio of nitrate nitrogen concentration to phosphate concentration (N / P ratio) in the effluent from the pre-aerated biofilm reactor is controlled to remain stable between 3.0 and 5.0. During this process, the following processes simultaneously occur within the pre-aerated biofilm reactor: (a) Ammonia nitrogen is nitrified into nitrate in the aerobic zone of the inner layer of the biofilm; (b) The remaining biodegradable organic matter in the wastewater is used as a carbon source in the anoxic zone outside the biofilm and in the main solution to denitrify and remove at least a portion of the nitrates produced in step (a). S3, Aerobic Phosphorus Absorption: The effluent from step S2 is treated under aerobic conditions so that the polyphosphate-accumulating bacteria can utilize the internal carbon source stored in their bodies to absorb excessive phosphorus. S4. Anaerobic endogenous denitrification: The effluent from step S3 is treated under anaerobic conditions so that the polyphosphate-accumulating bacteria can use the remaining internal carbon source in the body to carry out endogenous denitrification and nitrogen removal.

[0009] This application establishes an open network characterized by "functional carbon source diversion" featuring "synergistic interaction between aerobic polyphosphate-accumulating bacteria (PAOs) and ordinary heterotrophic denitrifying bacteria." Through a pre-matrix bioreactor (MABR), the carbon source stream is diverted both physically and chemically: residual COD is immediately utilized for denitrification by heterotrophic bacteria within the MABR; PHA, converted from volatile fatty acids (VFAs), is stored within the PAOs and dedicated to subsequent phosphorus uptake and endogenous denitrification. This shift from a "recycled" to a "diversion" core principle represents a breakthrough in the existing theoretical framework for nitrogen and phosphorus removal.

[0010] In one optional embodiment, the N / P ratio in the effluent of the membrane aerated biofilm reactor is 3.5-4.5, preferably 3.5-4.1. The wastewater denitrification and phosphorus removal method provided in this application is highly efficient and stable, with optimized carbon source distribution at the source, resulting in high denitrification and phosphorus removal efficiency.

[0011] In one optional embodiment, in step S2, the dissolved oxygen level of the bulk solution in the membrane aeration biofilm reactor and the N / P ratio of the effluent from the membrane aeration biofilm reactor are controlled by adjusting the gas pressure inside the membrane module of the membrane aeration biofilm reactor.

[0012] In an optional embodiment, the wastewater denitrification and phosphorus removal treatment method further includes an intelligent control step: based on the ammonia nitrogen and COD concentrations of the MABR unit influent, a basic setpoint for the membrane pressure is determined through feedforward calculation; based on the nitrate nitrogen and phosphate concentrations of the effluent from the membrane aerated biofilm reactor, the current nitrate nitrogen to phosphate concentration ratio is calculated and compared with a target ratio, and the adjustment amount of the membrane pressure is determined through feedback calculation; the basic setpoint and the adjustment amount are combined to obtain the final membrane pressure setpoint, and the MABR is controlled to operate according to this setpoint.

[0013] In one optional implementation, in step S2, the remaining readily biodegradable organic matter in the wastewater that was not absorbed by polyphosphate-accumulating bacteria in step S1 accounts for 30% to 70% of the chemical oxygen demand (COD) of the effluent in step S1.

[0014] In one optional embodiment, the polyphosphate-accumulating bacteria in step S1 include aerobic polyphosphate-accumulating bacteria, the polyphosphate-accumulating bacteria in step S3 include aerobic polyphosphate-accumulating bacteria, and the microorganisms performing denitrification in step S2 include heterotrophic denitrifying bacteria.

[0015] In one optional embodiment, the dissolved oxygen in the aerobic stage is 1.5-3 mg / L, and the hydraulic retention time (HRT) is 2-4 h. Since readily degradable organic matter has been largely consumed in the pre-MABR unit, the metabolic activity of aerobic heterotrophic bacteria is inhibited, the carbon source competition pressure is essentially relieved, and PAOs become the absolutely dominant functional bacterial group. They can efficiently and specifically utilize polyhydroxy fatty acid esters (PHA) stored in their cells as an energy source. This application, by controlling the dissolved oxygen in the aerobic stage at 1.5-3.0 mg / L and the HRT at 2.0-4.0 hours, can excessively absorb phosphates in the water (stored in the cells in the form of polyphosphates), achieving deep phosphorus removal (removal rate typically >90%). Simultaneously, residual ammonia nitrogen is further nitrified.

[0016] In one optional embodiment, the dissolved oxygen concentration during the anoxic phase is less than 0.5 mg / L, and the hydraulic retention time is 1-3 h. This application utilizes the residual PHA (typically accounting for 20%-40% of its initial storage) within PAOs after phosphorus uptake as an internal carbon source to drive endogenous denitrification, reducing residual nitrates in the water to nitrogen gas, thus completing the final deep denitrification. This process can further remove 20%-30% of the total nitrogen load.

[0017] In an optional embodiment, the wastewater denitrification and phosphorus removal method further includes returning the precipitated effluent after anoxic treatment to the anaerobic phosphorus release and carbon storage stage in step S1. The effluent after anoxic treatment enters the sedimentation unit for solid-liquid separation. The supernatant is the treated effluent that meets the standards. Part of the precipitated sludge is returned to the anaerobic stage to maintain the concentration of functional microorganisms such as PAOs in the system and to start a new metabolic cycle. The remaining sludge is discharged periodically.

[0018] The wastewater denitrification and phosphorus removal method provided in this application offers significant energy savings and reduced consumption. Firstly, it employs a MABR (Magnetic Aeration Bioreactor) system, which features bubble-free aeration and high oxygen utilization, resulting in energy savings of over 50%. Secondly, due to weak carbon source competition in the aerobic stage, the required aeration volume is reduced by approximately 30%. Thirdly, the unique process reduces or simplifies the need for internal recirculation. Therefore, the overall energy consumption is significantly lower than that of traditional ABR systems. 2The anaerobic-aerobic process reduces sludge production by 30%-50%. It also exhibits strong shock resistance and adaptability. Through intelligent control steps, it can quickly respond to fluctuations in influent water quality and quantity. By dynamically adjusting the MABR's "split ratio" (i.e., microaerobic level and SND efficiency) to redistribute carbon sources, it effectively buffers shocks and maintains system stability. Furthermore, it is highly engineering-friendly, based on conventional microbial communities (PAOs and heterotrophic bacteria), allowing for rapid system start-up (typically stabilizing within 15-25 days). Its stable microbial ecosystem makes operation and management less complex than processes relying on DPAOs, and it is easier to retrofit existing anaerobic-aerobic processes in wastewater treatment plants (by converting a portion of the aerobic tank into a MABR tank). Its application prospects are broad. The entire treatment process reduces sludge volume, using more carbon sources for energy metabolism rather than cell synthesis, avoiding the addition of external carbon sources. The system's sludge production rate can be reduced by 15%-25% compared to traditional processes.

[0019] On the other hand, this application provides a system for implementing the above-mentioned wastewater denitrification and phosphorus removal treatment method, comprising, in sequence along the wastewater flow direction: an anaerobic reaction unit for mixing the wastewater to be treated with activated sludge containing polyphosphate-accumulating bacteria, wherein the dissolved oxygen in the anaerobic reaction unit is ≤0.2 mg / L; a membrane aeration biofilm reaction unit, the inlet of which is connected to the outlet of the anaerobic reaction unit, wherein the membrane aeration biofilm reaction unit is provided with a membrane module, a gas pressure adjustable gas supply device connected to the membrane module, a dissolved oxygen monitoring instrument for monitoring dissolved oxygen in the unit, and an online water quality analysis instrument for monitoring the nitrate nitrogen and phosphate concentrations in the effluent; an aerobic reaction unit, the inlet of which is connected to the outlet of the membrane aeration biofilm reaction unit; an anoxic reaction unit, the inlet of which is connected to the outlet of the aerobic reaction unit; a sedimentation unit, the inlet of which is connected to the outlet of the anoxic reaction unit; and a sludge return unit, connecting the sludge zone of the sedimentation unit to the inlet of the anaerobic reaction unit.

[0020] In one optional embodiment, the wastewater denitrification and phosphorus removal system further includes an intelligent control unit, which is connected to the adjustable gas pressure supply device, the dissolved oxygen monitoring instrument, and the online water quality analysis instrument.

[0021] In one optional implementation, the operation method of the intelligent control unit includes: receiving effluent nitrate nitrogen concentration and phosphate concentration data monitored by the online water quality analyzer, calculating the current nitrate nitrogen to phosphate concentration ratio; comparing the current ratio with a preset target ratio range; generating a control command based on the comparison result, and sending it to the gas pressure adjustable gas supply device to adjust the internal gas pressure of the membrane module.

[0022] In one optional embodiment, the operation method of the intelligent control unit includes: receiving monitoring data of ammonia nitrogen concentration and chemical oxygen demand (COD) concentration of the effluent from the anaerobic reaction unit or the influent from the membrane aeration biofilm reaction unit; determining a basic set value of the membrane pressure based on the ammonia nitrogen concentration and COD concentration using a pre-stored feedforward calculation model; and making feedback adjustments based on the basic set value, combined with the comparison result of the current ratio and the target ratio, to obtain the final set value of the membrane pressure.

[0023] The technical solution of this application has the following advantages: 1. This application provides a wastewater denitrification and phosphorus removal method, comprising the following steps: S1, anaerobic phosphorus release and carbon storage: mixing wastewater with polyphosphate-accumulating bacteria under strictly anaerobic conditions, wherein the dissolved oxygen under the anaerobic conditions is ≤0.2 mg / L; S2, micro-aerobic diversion treatment in a pre-membrane aerated biofilm reactor: introducing the effluent from step S1 into a membrane aerated biofilm reactor, controlling the dissolved oxygen in the main solution within the reactor to operate within a micro-aerobic range of 0.3 mg / L to 0.7 mg / L, and controlling the ratio of nitrate nitrogen concentration to phosphate concentration in the effluent from the reactor to be between 3.0 and 5.0; S3, aerobic phosphorus uptake: treating the effluent from step S2 under aerobic conditions; S4, anoxic endogenous denitrification: treating the effluent from step S3 under anoxic conditions. This application utilizes anaerobic conditions with dissolved oxygen less than or equal to 0.2 mg / L to enable polyphosphate-accumulating bacteria (PAOs) in activated sludge to absorb easily biodegradable organic matter such as volatile fatty acids in wastewater, converting them into polyhydroxyalkanoates and storing them intracellularly as an internal carbon source. Simultaneously, the intracellular polyphosphates are decomposed and released into the water, increasing the phosphate concentration in the effluent during the anaerobic stage. The remaining easily biodegradable organic matter in the wastewater that is not absorbed by PAOs (accounting for approximately 30%-70% of the COD at the anaerobic effluent) is preferentially utilized by heterotrophic denitrifying bacteria in the anoxic layer and main solution of the membrane biofilm reactor (MABR) stage, serving as a carbon source and electron donor to drive the denitrification reaction. At the same time, oxygen diffuses through the membrane wall, forming an aerobic zone in the inner layer of the biofilm closely attached to the membrane surface, where ammonia nitrogen is efficiently oxidized to nitrate. A portion of the generated nitrate is immediately consumed by the denitrification process, achieving in-situ, efficient, simultaneous nitrification and denitrification. Furthermore, the dissolved oxygen in the main solution within the MABR reactor is stably controlled within a narrow micro-aerobic range of 0.3 mg / L to 0.7 mg / L. Dissolved oxygen at this stage is crucial for ensuring efficient simultaneous nitrification and denitrification. Moreover, by controlling the effluent nitrogen-to-phosphorus ratio of the membrane-aerated biofilm reactor to 3-5:1, the key process of pre-denitrification can be effectively connected to subsequent biological phosphorus removal, driving the aerobic phosphorus uptake metabolism of polyphosphate-accumulating bacteria. In this step of the MABR process, a portion of the nitrogen load (typically 30-50% of the total nitrogen in the influent) is pre-removed through the consumption of the remaining external carbon source. More importantly, the internal carbon source synthesized by polyphosphate-accumulating bacteria during the anaerobic stage is effectively protected during this stage, with its consumption rate typically below 15%. Therefore, the effluent after the MABR treatment stage is characterized by "low carbon (significantly reduced COD), moderate nitrification (moderate nitrate concentration), high phosphorus (high phosphate concentration), and high PHA (high PAO) activity." This application repositions and relocates the MABR, transforming it from a traditional "end-of-pipe treatment unit" or "simple functional unit" into a "pre-carbon source intelligent diversion and control hub" located after the anaerobic stage.By creating and precisely controlling the carbon sources in wastewater to be "diverted" in a physicochemical sense according to predetermined functional pathways before entering the traditional competitive stages, a completely new and efficient pollutant synergistic removal pathway is constructed on the basis of conventional and stable microbial communities (aerobic polyphosphate-accumulating bacteria and ordinary heterotrophic denitrifying bacteria), realizing a paradigm shift from "carbon source competition" or "microbial cycle" to "carbon source pre-diversion according to function".

[0024] It is important to note that the inventiveness of this application lies in the "pre-positioning" of the MABR unit, while simultaneously meeting the following two key technical conditions: 1) operating within a specific micro-aerobic range (0.3-0.7 mg / L) to achieve efficient simultaneous nitrification and denitrification; 2) focusing on controlling a specific N / P ratio (3.0-5.0) in the effluent to achieve precise "separation" of carbon sources for denitrification and create optimal conditions for subsequent biological phosphorus removal. This combination of technical features fundamentally changes the function of the MABR, constructing a completely new "carbon source separation" paradigm.

[0025] 2. This application provides a wastewater nitrogen and phosphorus removal system, comprising, sequentially along the wastewater flow direction: an anaerobic reaction unit for mixing the wastewater to be treated with activated sludge containing polyphosphate-accumulating bacteria; a membrane aeration biofilm reaction unit, the inlet of which is connected to the effluent of the anaerobic reaction unit, the membrane aeration biofilm reaction unit being equipped with a membrane module, a gas pressure adjustable gas supply device connected to the membrane module, a dissolved oxygen monitoring instrument for monitoring dissolved oxygen in the unit, and an online water quality analysis instrument for monitoring the effluent nitrate nitrogen and phosphate concentrations; an aerobic reaction unit, the inlet of which is connected to the effluent of the membrane aeration biofilm reaction unit; and an anoxic reaction unit, the inlet of which is connected to the effluent of the aerobic reaction unit. This application, by pre-processing a MABR and controlling the N / P ratio of the effluent after MABR treatment, actively guides the carbon flow, solving the core contradiction of the system from the source and fully releasing the technical potential of MABR.

[0026] 3. This application provides a wastewater denitrification and phosphorus removal system. The operation steps of the intelligent control unit include: receiving effluent nitrate nitrogen and phosphate concentration data monitored by the online water quality analyzer; calculating the current nitrate nitrogen to phosphate concentration ratio; comparing the current ratio with a preset target ratio range; generating a control command based on the comparison result and sending it to the gas pressure adjustable gas supply device to adjust the internal gas pressure of the membrane module. This application proposes a composite control strategy with the dual objectives of "maintaining a micro-aerobic environment" and "stabilizing the effluent nitrogen-phosphorus ratio." The control objective has been deepened from traditional end-of-pipe water quality indicators to regulating the material balance and kinetic processes of key biochemical reactions within the system. This achieves cross-unit (MABR and aerobic / anoxic) synergistic optimization, greatly improving the system's intelligence level, operational stability, and resistance to shock loads. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a wastewater denitrification and phosphorus removal system provided in Embodiment 1 of this application; Figure 2 This is a schematic diagram of a wastewater denitrification and phosphorus removal method provided in Embodiment 1 of this application; Figure 3 This is a schematic diagram of the operation steps of the intelligent control unit in a wastewater denitrification and phosphorus removal system provided in Embodiment 1 of this application; Figure 4 This is a schematic diagram of the adaptive control algorithm of an intelligent unit in a wastewater denitrification and phosphorus removal system provided in Embodiment 1 of this application. Detailed Implementation

[0029] The following embodiments are provided to better understand this application. However, the following embodiments do not constitute a limitation on the content and scope of protection of this application. Any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining the features of this application with other prior art, falls within the scope of protection of this application.

[0030] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0031] In the embodiments of this application, the N / P ratio refers to the ratio of nitrate nitrogen concentration to phosphate concentration; DO represents dissolved oxygen concentration; ORP represents oxidation-reduction potential; SRT represents sludge age; PAOs represent polyphosphate-accumulating bacteria; DPAOs represent denitrifying polyphosphate-accumulating bacteria; and PHA represents polyhydroxyalkanoates.

[0032] Example 1 This embodiment provides a method and system for nitrogen and phosphorus removal from wastewater, the details of which are as follows: At the pilot plant of a wastewater treatment R&D center, a treatment capacity of 5 m³ / s was constructed. 3 A wastewater denitrification and phosphorus removal system with a capacity of / d is used to treat simulated urban domestic wastewater with a low carbon-to-nitrogen ratio.

[0033] (1) Influent water quality: COD: 180-220 mg / L (of which, soluble COD accounts for approximately 65 wt%); BOD5: 80-110 mg / L; NH4 + -N: 40-50 mg / L; TN: 45-55 mg / L; TP: 4.5-5.5 mg / L; pH: 7.0-7.8; C / N ratio (in terms of COD / TN): 3.8-4.2.

[0034] (2) System Configuration The anaerobic reaction unit includes an anaerobic tank with an effective volume of 1.0 m³. 3 Hydraulic retention time (HRT) = 4.8 h, closed system, built-in submersible mixer (power 0.75 kW), with biogas collection pipe at the top; The membrane aeration biofilm reactor unit includes a MABR reactor with an effective volume of 3.0 m³. 3 HRT = 14.4 h. Internally mounted hollow fiber membrane module (membrane area 150 m²). 2 The membrane flux is approximately 0.02 Nm. 3 / (m 2 •h)), equipped with a distributed dissolved oxygen (DO) sensor (3 measuring points) and a precision gas pressure control system (pressure adjustment range 5-30 kPa), and an online nitrate analyzer and an online phosphate analyzer are installed at the outlet; The aerobic reaction unit includes an aerobic tank with an effective volume of 2.0 m³. 3 HRT=9.6 h, microporous aeration is used, and the aeration rate is adjustable; The anoxic reaction unit includes an anoxic tank with an effective volume of 1.5 m³. 3HRT=7.2 h, built-in low-speed thruster; The sedimentation unit includes a secondary sedimentation tank, which is vertically flowed and has a surface loading rate of 0.8 m³. 3 / (m 2 ·h); The sludge return unit includes a screw pump and a sludge return pipe, with a return ratio of up to 100% (adjustable). Intelligent control unit: It adopts a programmable logic controller (PLC) with a control cycle set to 10 minutes.

[0035] Reference Figure 1 As shown, in the wastewater denitrification and phosphorus removal system provided in this embodiment, the effluent outlet of the anaerobic tank is connected to the inlet of the MABR reactor, the effluent outlet of the MABR reactor is connected to the inlet of the aerobic tank, the effluent outlet of the aerobic tank is connected to the inlet of the anoxic tank, the effluent outlet of the anoxic tank is connected to the inlet of the secondary sedimentation tank, the sludge zone of the secondary sedimentation tank is connected to the sludge return unit, and the sludge outlet of the sludge return unit is connected to the anaerobic tank. The MABR reactor is equipped with online monitoring instruments and a gas pressure control device. The intelligent control unit determines whether to adjust the gas pressure of the gas pressure control device based on the data fed back from the online monitoring instruments.

[0036] (3) Operating parameters and control objectives: Anaerobic tank: DO < 0.2 mg / L, ORP < -250 mV.

[0037] MABR reactor: Control objective 1: Main solution DO stabilized at 0.4-0.6 mg / L; effluent N / P ratio stabilized between 3.5-4.1 (ideal value R_target=3.8). Achieved by adjusting the membrane pressure (set range 8-18 kPa).

[0038] Aerobic tank: DO controlled at 2.0±0.5 mg / L.

[0039] Anoxic pool: DO < 0.5 mg / L.

[0040] Sludge retention time (SRT) should be controlled at 18-22 days.

[0041] (4) Start-up and operation, refer to Figure 2 As shown: 4.1 Anaerobic phosphorus release and carbon storage: Wastewater is mixed with polyphosphate-accumulating bacteria under strict anaerobic conditions, wherein the dissolved oxygen concentration under the anaerobic conditions is ≤0.2mg / L, so that polyphosphate-accumulating bacteria in the sludge absorb easily biodegradable organic matter in the wastewater and synthesize internal carbon sources, while releasing phosphates; 4.2 Pre-treatment with micro-oxygenation in MABR: The effluent from step S1 is introduced into the MABR unit. By adjusting the gas pressure inside the membrane module of the MABR unit, the micro-oxygen environment with DO of 0.3 mg / L to 0.7 mg / L and the N / P ratio of the effluent from the MABR unit are controlled between 3.0 and 5.0. 4.3 Aerobic Phosphorus Absorption: The effluent from S2 is treated under aerobic conditions, so that polyphosphate-accumulating bacteria can use the internal carbon source stored in their bodies to excessively absorb phosphates in the water. 4.4. Anaerobic endogenous denitrification: The effluent from S3 is treated under anaerobic conditions so that polyphosphate-accumulating bacteria can use the remaining internal carbon source in their bodies to carry out denitrification and nitrogen removal.

[0042] More specific steps are as follows: Inoculate the secondary sedimentation tank return sludge of a municipal wastewater treatment plant (mixed liquor suspended solids concentration (MLSS) ≈ 3000 mg / L). In the initial stage of startup, the MABR tank is first converted to a normal aeration unit and operated for about 7 days. After the sludge adapts, switch to the operating mode of this embodiment, adjust the operating parameters and control targets to step (3) of this embodiment, and gradually turn on the intelligent control of the MABR, referring to... Figure 3 As shown, the control parameters were adjusted. For specific control methods, please refer to the control method in this embodiment. The system reached a stable operating state on the 18th day, and the functional bacterial groups (nitrifying bacteria, PAOs) of each unit were significantly enriched.

[0043] (5) Performance data during stable operation: The performance data for stable operation of this embodiment from day 20 to day 50 is shown in Table 1.

[0044] Table 1 Performance Data 1

[0045] According to the performance data in Table 1, the wastewater denitrification and phosphorus removal method provided in this embodiment can effectively remove COD, ammonia nitrogen, total phosphorus and total nitrogen from wastewater.

[0046] Meanwhile, by periodically sampling the effluent from the anaerobic tank and the activated sludge from the MABR tank, the PHA content in the activated sludge in the effluent from the anaerobic tank and the MABR tank was determined by gas chromatography. The average PHA content (calculated as COD) in the effluent from the anaerobic tank was 35.2 mg COD / g VSS, while that in the effluent from the MABR tank was 32.1 mg COD / g VSS, with a PHA retention rate of 91.2%. This data confirms that the microaerobic environment of the MABR unit effectively achieves carbon source diversion and protects the internal carbon source (PHA) in the PAOs from being consumed.

[0047] Based on material balance calculations and estimates from specific batch experiments, approximately 62% of the influent COD is consumed as residual COD in the MABR unit (mainly for denitrification), approximately 30% is converted into PHA and enters subsequent units (for phosphorus uptake and endogenous denitrification), and the remainder is either inert or residual sludge.

[0048] High-throughput sequencing was performed on the sludge from the aerobic tank after 40 days of stable operation to analyze the microbial community. Typical polyphosphate-accumulating bacteria were observed in the aerobic tank sludge. Candidatus Accumulibacter The relative abundance reached 31.5%, significantly higher than that of traditional A. 2 / O process (approximately 15%). In the MABR tank biofilm, nitrifying bacteria ( Nitrosomonas, Nitrospira ) and common denitrifying bacteria (such as Denitratisoma, Thaurea The abundance was high, but no significant DPAOs characteristic bacterial groups were detected.

[0049] On the 45th day of stable operation, ammonia nitrogen shock in the influent was simulated, and the influent NH4 was... + The -N concentration increased from 45 mg / L to 65 mg / L within 2 hours and remained elevated for 6 hours. The intelligent control system in this embodiment responded rapidly, automatically increasing the membrane pressure from 12.5 kPa to 16.8 kPa to enhance nitrification. The effluent TN reached a maximum of 9.5 mg / L during the shock event, but recovered to below 8.0 mg / L within 8 hours after the shock ended, indicating that the system in this embodiment exhibits good shock resistance and self-recovery capability.

[0050] During stable operation, the total energy consumption of the system (including stirring, aeration, reflux, control instruments, etc.) is approximately 0.25 kWh / m³. 3 Of these, the gas supply energy consumption of the MABR unit accounts for approximately 35%, and the aeration energy consumption of the aerobic tank accounts for approximately 25%. Compared to traditional ABR systems treating similar water quality, this is significantly lower. 2 / O process (energy consumption approximately 0.38 kWh / m) 3 It saves approximately 34% on energy.

[0051] This embodiment also details the specific steps and logic of the feedforward-feedback composite adaptive control algorithm executed by the intelligent control unit (ICU). This algorithm executes cyclically at a fixed time period (e.g., 10 minutes). Its core objective is to maintain the micro-aerobic environment of the MABR reactor and stabilize the nitrate nitrogen to phosphate concentration ratio (N / P ratio) of its effluent within a preset range, thereby achieving stable carbon source diversion. See the attached document for details. Figure 4 As shown in the figure, this embodiment provides a control method for an intelligent control unit in a wastewater nitrogen and phosphorus removal system, including the following steps: (1) Parameters Input variables (implemented detection values): NH_in: Ammonia nitrogen concentration in the influent of the MABR reactor (mg / L); COD_in: Chemical oxygen demand of MABR reactor influent (mg / L); DO_mabr: Dissolved oxygen in the bulk solution of the MABR reactor (mg / L); NO3_out: Nitrate nitrogen concentration (mg / L) in the effluent from the MABR reactor. PO4_out: Phosphate concentration (mg / L) in the effluent from the MABR reactor. Output variables: P_set: The setpoint (kPa) of the internal gas pressure of the membrane module sent to the gas pressure control device. Internal variables and preset parameters: P_base: Base pressure value (kPa) obtained through feedforward calculation; R_now: The current N / P ratio calculated based on real-time monitoring values. R_now = NO3_out / PO4_out; R_target: Target N / P ratio, set R_target = 3.8; Deadband: Control dead zone, set to 0.3. When the N / P ratio deviation is within this range, no pressure adjustment is performed to avoid frequent system operation; Kp: Proportional control coefficient, determined based on system debugging, for example, it can be set to 1.5 kPa / (unit N / P ratio deviation). P_min, P_max: The safe operating range of the membrane pressure, for example, set to 8 kPa and 22 kPa respectively; DO_low, DO_high: Target control ranges for dissolved oxygen in the MABR tank, for example, set to 0.4 mg / L and 0.6 mg / L respectively; (2) Control methods The intelligent control unit executes the following control algorithm at a fixed cycle (e.g., every 10 minutes): 2.1 Data Acquisition and Preprocessing: The intelligent control unit reads the latest water quality and operating parameter data from all online monitoring instruments. First, the validity of the data is checked, such as whether the values ​​are within a reasonable range and whether the rate of change is abnormal. Then, key parameters such as DO_mabr, NO3_out, and PO4_out are digitally filtered (e.g., using a moving average method) to eliminate the interference of accidental measurement errors and instantaneous fluctuations on the control system.

[0052] 2.2. Feedforward calculation: The basic oxygen demand of the MABR unit is predicted based on the real-time load of the influent, and the basic pressure setpoint P_base is calculated accordingly.

[0053] Specifically, the calculation is performed using an empirical formula based on historical operational data, for example:

[0054] The constants and coefficients (10.0, 0.15, 0.02) and reference values ​​(40, 200) in the formula can be calibrated according to the actual equipment scale and influent characteristics. The calculated P_base value will be limited to a pre-set reasonable range (e.g., 9 kPa to 16 kPa) as a reference for feedback adjustment.

[0055] 2.3. Feedback Calculation and Deviation Determination: First, determine if PO4_out is greater than a very small threshold (e.g., 0.2 mg / L) to avoid calculation failure due to division by zero or near zero. If the condition is met, calculate the current N / P ratio: R_now = NO3_out / PO4_out. If not, assign a higher default value to R_now (e.g., 20). This strategy aims to encourage the system to increase pressure to ensure nitrification when phosphorus concentration is extremely low. Next, calculate the control deviation E = R_target - R_now.

[0056] 2.4. Feedback control decision: Determine whether the absolute value of the current deviation E exceeds the set deadband.

[0057] If |E|>Deadband: This indicates that the current N / P ratio deviates significantly from the target value and needs adjustment. The pressure adjustment ΔP is calculated using a proportional control law, i.e., ΔP = Kp × E. When R_now is higher than the target range (E is negative), ΔP is negative, meaning that the membrane pressure needs to be reduced to weaken oxygen mass transfer and promote denitrification, thereby reducing R_now. Conversely, when R_now is lower than the target range, ΔP is positive, meaning that the pressure needs to be increased to enhance nitrification, thereby increasing R_now.

[0058] If |E| ≤ Deadband: This indicates that the current N / P ratio is within the acceptable target range, and no active adjustment is made, i.e., let ΔP = 0.

[0059] 2.5. Dissolved oxygen monitoring and overall pressure calculation: First, calculate the initial pressure setpoint P_temp = P_base + ΔP.

[0060] Subsequently, dissolved oxygen monitoring and protection logic was introduced: If DO_mabr is consistently higher than the upper limit DO_high, and the calculated deviation E is positive (meaning that pressure needs to be increased to enhance nitrification), then P_temp should be appropriately suppressed (e.g., multiplied by a coefficient slightly less than 1) to prevent blindly increasing pressure under already oxygen-enriched conditions.

[0061] If DO_mabr is continuously lower than the lower limit DO_low and the deviation E is negative (meaning that the pressure needs to be reduced to promote denitrification), a low dissolved oxygen alarm will be triggered, and P_temp will be limited to not be lower than P_base to ensure basic nitrification requirements and prevent the system from entering a severe hypoxia state.

[0062] Finally, a safety limit is applied to the calculated P_temp to ensure that it does not exceed the allowable operating pressure range of the membrane module: P_set = max(P_min, min(P_max, P_temp)).

[0063] 2.6. Control command output and data recording: The final determined intra-membrane pressure setpoint P_set is sent to the gas pressure control device for execution. Simultaneously, all input data, intermediate variables, calculation processes, and output control commands within this control cycle are recorded in the system's historical database for operational monitoring, performance analysis, and algorithm optimization.

[0064] Example 2 This embodiment provides a wastewater denitrification and phosphorus removal system and method that is the same as in Embodiment 1, except that the nitrogen-to-phosphorus ratio at the effluent outlet of the MABR reactor is 4.0-4.5 mg / L. Under these conditions, the system takes approximately 22 days to start up and stabilize. After stable operation, the average effluent TN is 6.8 ± 1.0 mg / L, and the average effluent TP is 0.15 ± 0.05 mg / L.

[0065] Example 3 This embodiment provides a wastewater denitrification and phosphorus removal system and method that is the same as in Embodiment 1, except that the nitrogen-to-phosphorus ratio at the effluent outlet of the MABR reactor is 3.0-3.5 mg / L. Under these conditions, the system takes approximately 23 days to start up and stabilize. After stable operation, the average effluent TN is 7.5 ± 1.1 mg / L, and the average effluent TP is 0.10 ± 0.03 mg / L.

[0066] Example 4 This embodiment provides a wastewater denitrification and phosphorus removal system and method that is the same as in Embodiment 1, except that the DO in the MABR reactor is stabilized at 0.3-0.4 mg / L. Under these low DO conditions, nitrification is slightly limited, and the system startup to stabilization time is extended to approximately 25 days. After stable operation, the average effluent TN is 8.2±1.2 mg / L, and the average effluent TP is 0.18±0.06 mg / L.

[0067] Example 5 This embodiment provides a wastewater denitrification and phosphorus removal system and method that is the same as in Embodiment 1, except that the DO in the MABR reactor is stabilized at 0.5-0.7 mg / L. Under these conditions, the system takes approximately 26 days to stabilize after startup. After stable operation, the average effluent TN is 7.0±1.0 mg / L, and the average effluent TP is 0.14±0.05 mg / L.

[0068] Comparative Example 1 This comparative example provides a wastewater nitrogen and phosphorus removal treatment system and method that are the same as those in Example 1, except that the effluent N / P ratio is controlled at 2-2.5 mg / L. Due to severe nitrification insufficiency, the system struggles to reach stable operation within 60 days, with the startup to stabilization time exceeding 32 days. After attempting stable operation, the average effluent TN was as high as 15.2 ± 2.8 mg / L, and the average effluent TP was 1.5 ± 0.4 mg / L, indicating poor phosphorus removal efficiency.

[0069] Comparative Example 2 This comparative example provides a wastewater nitrogen and phosphorus removal treatment system and method that are the same as those in Example 1, except that the effluent N / P ratio is controlled at 5.2-5.5 mg / L. Due to insufficient denitrification leading to nitrate accumulation and an imbalance in the ratio of electron acceptors (nitrate) provided for subsequent phosphorus uptake, the system takes approximately 34 days to stabilize. After stable operation, the average effluent TN is 12.8 ± 2.0 mg / L, and the average effluent TP is 0.8 ± 0.3 mg / L.

[0070] Comparative Example 3 This comparative example provides a wastewater denitrification and phosphorus removal system and method that is the same as in Example 1, except that it is inoculated with return sludge from the secondary sedimentation tank of a municipal wastewater treatment plant (mixed liquor suspended solids concentration (MLSS) ≈ 3000 mg / L). Initially, it was run in an aerobic environment (DO 3 mg / L) for 21 days, followed by an anoxic environment (0.4 mg / L) for 16 days. After the sludge adapted, it was switched to the operating mode of Example 1, and the intelligent control of the MABR was gradually activated and the control parameters were adjusted. Due to the mismatch between the bacterial culture target and the process of this application, the system only reached a basically stable operating state on the 35th day, and the operating effect was unsatisfactory.

[0071] Application examples Taking an existing urban wastewater treatment plant as an example, the plant originally used A 2 The / O process, designed for a capacity of 50,000 tons / day, has a low influent C / N ratio (approximately 3.5-4.0), requiring continuous addition of sodium acetate (approximately 200-300 mg / L) to ensure TN compliance, resulting in high operating costs. The treatment system and methods provided in this application will be used for upgrading and modification.

[0072] 1. Renovation Plan: Utilize the existing anaerobic tank (unchanged); The first third of the original anoxic tank was converted into a MABR tank, in which MABR membrane modules (total membrane area of ​​approximately 500,000 square meters) were submerged and installed, along with a gas supply system, an online monitoring system, and an intelligent control cabinet. The remaining part of the original anoxic tank and the aerobic tank remain unchanged in function, but the aeration rate of the aerobic tank can be appropriately reduced due to the decrease in influent COD. The existing secondary sedimentation tank and sludge return system remain unchanged; A new intelligent control system has been added and integrated into the original factory control room.

[0073] Wastewater is treated according to the treatment method provided in Embodiment 1 of this application.

[0074] 2. Effect after modification: Without increasing the pool capacity, the processing capacity can be increased by about 15% (due to the high efficiency of MABR, the total HRT can be slightly shortened). Stopping the addition of external carbon sources saves approximately 5 million yuan annually in sodium acetate costs. The effluent TN can be stably increased from <12 mg / L before the modification to <8 mg / L, and TP <0.3 mg / L; Aeration energy consumption is expected to be reduced by 20%-30%, and overall energy consumption by 15%-20%. The system's ability to withstand water inflow fluctuations has been enhanced, and its operation and management are now simpler.

[0075] Experimental Example To objectively evaluate the effectiveness of this application, the treatment systems and methods of Examples 1-5 and Comparative Examples 1-3 of this application were run in parallel under the same pilot-scale conditions. The wastewater treatment process was simulated according to the wastewater treatment method provided in Example 1 of Publication No. CN121269973A to treat the influent water quality provided in Example 1. The system was run synchronously for 60 days, and the performance data were recorded and measured. The results are shown in Table 2.

[0076] Table 2 Performance Data II

[0077] As shown in Table 2, compared to denitrifying polyphosphate-accumulating bacteria with large abundance fluctuations, this application, based on conventional microbial communities and enriched with a broad spectrum of polyphosphate-accumulating bacteria, can shorten system start-up time and improve operational start-up efficiency. The system provided by this application has superior nitrogen and phosphorus removal effects and stronger shock resistance. At the same time, the system provided by this application operates under milder conditions, with less potential membrane fouling, and can also save energy, showing good operational prospects. Specifically, in the existing wastewater treatment methods, DPAOs in the anoxic stage need to utilize PHA to simultaneously complete denitrification and phosphorus uptake. Therefore, when the carbon source is insufficient (in wastewater with a low C / N ratio), denitrification and phosphorus uptake mutually restrict each other. This application, by placing the MABR membrane in the pre-flow stage, diverts the carbon source, utilizing the remaining COD from the anaerobic stage for denitrification on the one hand, and utilizing the enriched PHA for phosphorus uptake on the other, decoupling in space and time, fundamentally avoiding competition. Meanwhile, denitrifying polyphosphate-accumulating bacteria are sensitive to nitrate concentration. When the nitrate concentration in the MABR return fluctuates, it easily affects DPAO metabolism, leading to unstable phosphorus removal (large TP fluctuations were observed in the experiment). The wastewater treatment method provided in this application has a clearly defined PAO metabolic pathway, is less affected by nitrates, and has high aerobic phosphorus uptake efficiency.

[0078] Examples 2-5, with minor adjustments to the core parameters (DO, N / P ratio) within their preferred ranges, all maintained the core function of "carbon source diversion," achieving good and stable treatment results, demonstrating the robustness of the parameter range in this application. However, Comparative Examples 1-3, once deviated from the core concept of this application (e.g., N / P ratio exceeding the range of 3.0-5.0, or using an incorrect microbial community startup method), showed significant deterioration in system performance. This, in turn, proves that the technical features claimed in this application (pre-MABR, specific micro-oxygen DO range, specific effluent N / P ratio range, and their synergy) are necessary and not obvious for achieving the aforementioned beneficial effects.

[0079] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A method for treating wastewater to remove nitrogen and phosphorus, characterized in that, Includes the following steps: S1, Anaerobic phosphorus release and carbon storage: Wastewater is mixed with polyphosphate-accumulating bacteria under anaerobic conditions, wherein dissolved oxygen is ≤0.2mg / L; S2. Pre-aerated biofilm reactor micro-aerobic diversion treatment: The effluent from step S1 is introduced into the pre-aerated biofilm reactor, and the operation of the pre-aerated biofilm reactor is adjusted to simultaneously meet the following conditions: The dissolved oxygen in the bulk solution of the membrane-aerated biofilm reactor is maintained in a micro-oxygen environment of 0.3 mg / L to 0.7 mg / L. The N / P ratio in the effluent of the membrane-aerated biofilm reactor is stable at 3.0 to 5.

0. S3, Aerobic Phosphorus Absorption: The effluent from step S2 is treated under aerobic conditions; S4. Anoxic endogenous denitrification: The effluent from step S3 is treated under anoxic conditions.

2. The processing method according to claim 1, characterized in that, In step S2, the dissolved oxygen level of the main solution in the membrane aeration biofilm reactor and the N / P ratio of the effluent from the membrane aeration biofilm reactor are controlled by adjusting the gas pressure inside the membrane module of the membrane aeration biofilm reactor.

3. The processing method according to claim 2, characterized in that, It also includes intelligent control steps: Based on the ammonia nitrogen and COD concentrations in the influent of the membrane aerated biofilm reactor, the basic set value of the gas pressure inside the membrane is determined by feedforward calculation. Based on the N / P ratio of the effluent from the membrane aerated biofilm reactor and compared with the target N / P ratio, the adjustment amount of the gas pressure inside the membrane is determined through feedback calculation. The basic setting value and the adjustment amount are combined to obtain the final membrane gas pressure setting value, and the membrane aeration biofilm reactor is controlled to operate according to this setting value.

4. The processing method according to claim 1, characterized in that, In step S2, the remaining easily biodegradable organic matter in the wastewater that was not absorbed by polyphosphate-accumulating bacteria in step S1 accounts for 30% to 70% of the chemical oxygen demand of the effluent from step S1.

5. The processing method according to claim 1, characterized in that, The polyphosphate-accumulating bacteria in step S1 and / or step S3 include aerobic polyphosphate-accumulating bacteria, and the microorganisms performing denitrification in step S2 include heterotrophic denitrifying bacteria.

6. The processing method according to claim 1, characterized in that, The wastewater denitrification and phosphorus removal treatment method also includes returning the precipitated effluent after anoxic treatment and the precipitated sludge to the anaerobic phosphorus release and carbon storage stage of step S1.

7. A wastewater denitrification and phosphorus removal system for implementing the method according to any one of claims 1-6, characterized in that, Along the direction of sewage flow, the following are included in sequence: Anaerobic reaction unit is used to mix wastewater to be treated with activated sludge containing polyphosphate-accumulating bacteria; The membrane aeration biofilm reactor unit has its inlet end connected to the outlet end of the anaerobic reactor unit. The membrane aeration biofilm reactor unit is equipped with a membrane module, a gas pressure adjustable gas supply device connected to the membrane module, a dissolved oxygen monitoring instrument for monitoring dissolved oxygen in the unit, and an online water quality analysis instrument for monitoring the concentration of nitrate nitrogen and phosphate in the effluent. An aerobic reaction unit, the inlet of which is connected to the outlet of the membrane aeration biofilm reaction unit; The anoxic reaction unit has its inlet end connected to the outlet end of the aerobic reaction unit.

8. The system according to claim 7, characterized in that, The system also includes a sedimentation unit and a sludge return unit. The inlet of the sedimentation unit is connected to the outlet of the anoxic reaction unit. The sludge return unit connects the sludge zone of the sedimentation unit to the inlet of the anaerobic reaction unit. And / or, the system further includes an intelligent control unit, which is connected to the gas pressure adjustable gas supply device, the dissolved oxygen monitoring instrument, and the online water quality analysis instrument.

9. The system according to claim 8, characterized in that, The operation steps of the intelligent control unit include: Receive the effluent nitrate nitrogen concentration and phosphate concentration data monitored by the online water quality analyzer, and calculate the current nitrate nitrogen to phosphate concentration ratio; Compare the current ratio with the preset target ratio range; Based on the comparison results, a control command is generated and sent to the gas pressure adjustable gas supply device to adjust the internal gas pressure of the membrane module.

10. The system according to claim 9, characterized in that, The operation steps of the intelligent control unit also include: Receive monitoring data on ammonia nitrogen concentration and chemical oxygen demand concentration in the effluent of the anaerobic reaction unit or the influent of the membrane aerated biofilm reaction unit; Based on the ammonia nitrogen concentration and chemical oxygen demand concentration, the basic set value of the membrane pressure is determined by a pre-stored feedforward calculation model. Based on the aforementioned basic setting value, feedback adjustments are made by combining the comparison results of the current ratio and the target ratio to obtain the final membrane pressure setting value.

Images