System and method for classified sewage treatment

Abstract

The invention discloses a system and a method for classified sewage treatment, and belongs to the technical field of environmental engineering and water treatment. The system comprises the following components: an intelligent water quality detection module, which is used for real-time and accurate monitoring of COD, BOD, ammonia nitrogen, total phosphorus, suspended matter concentration and heavy metal content; the sectional bioreactor realizes deep removal of nitrogen and phosphorus and efficient biological treatment by flexibly adjusting reaction conditions of each section; the intelligent flocculation control module is used for automatically and accurately adjusting the adding amount of a flocculating agent, and is combined with integrated operation of efficient inclined tube precipitation and sludge concentration, so that the water quality of discharged water is stable, and the medicament consumption is reduced; the ultrafiltration membrane bioreactor effectively removes residual suspended matters and colloids, and ensures that the effluent stably reaches the standard for a long time through the synergistic effect of catalytic ozonation; and the sludge treatment module is used for realizing collaborative optimization management of sludge reduction, recycling and energy recycling.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental engineering and water treatment technology, in particular to a system and method for classified sewage treatment. Combined with multi-parameter high-precision online monitoring, intelligent hierarchical control, multi-unit collaborative treatment and dynamic process path optimization technology, accurate treatment, deep purification and efficient operation and management of sewage with different pollution levels and different water quality characteristics can be realized, which belongs to the field of sewage treatment automation and intelligent technology. BACKGROUND

[0002] With the accelerated development of industrialization and urbanization, the amount of sewage discharge continues to increase, and the types and concentrations of pollutants tend to diversify and complicate. Traditional sewage treatment plants mostly use fixed process flow, such as A / O or A / O biological treatment process, combined with sedimentation, filtration and disinfection units, to achieve reduction of organic matter, nitrogen, phosphorus and other pollutants. However, such fixed process is often designed based on single or relatively stable water quality conditions, and when facing fluctuating pollution load or unconventional pollutants such as heavy metals and refractory organic matter, the treatment effect is prone to be unstable or even exceed the standard. 2

[0003] Existing sewage treatment technology still has deficiencies in online monitoring and dynamic control. Common water quality monitoring methods mostly rely on manual sampling and testing or single sensor detection, which cannot real-time and comprehensively grasp the changes of key indicators such as COD, BOD, ammonia nitrogen, total phosphorus, suspended solids and heavy metals; in terms of treatment strategy, traditional biological reactors are mostly single or double stage type, lacking flexible and adjustable reaction conditions, which makes it difficult to achieve optimal denitrification and phosphorus removal or deep purification under different pollution levels and different water quality characteristics; in addition, flocculation, membrane separation and ozone oxidation units often operate independently, lacking collaborative control and intelligent optimization, resulting in high reagent consumption, high energy consumption, high sludge volume and high operation cost.

[0004] In recent years, intelligent and multi-parameter integrated technology has been gradually introduced into the field of sewage treatment. For example, multi-spectral detection, electrochemical sensing, laser scattering and other means are used to improve monitoring accuracy; segmented reactors or multi-stage processes are used to improve the removal efficiency of different pollutants; membrane separation or advanced oxidation units are used to strengthen deep treatment. However, these technologies are mostly single-point or local improvements, lacking systematic integration and dynamic process path generation mechanism based on real-time water quality, and cannot realize real "on-demand" treatment and whole-process optimization control.

[0005] In summary, how to realize multi-parameter high-precision real-time monitoring, intelligent hierarchical decision-making based on pollution level, flexible and adjustable multi-unit collaborative treatment and dynamic process path optimization in the process of sewage treatment has become a technical problem to be solved. SUMMARY

[0006] ​In order to overcome a series of defects existing in the prior art, the purpose of the present application is to provide a system for classifying sewage treatment, comprising the following components:

[0007] An intelligent water quality detection module is used for real-time and accurate monitoring of COD, BOD, ammonia nitrogen, total phosphorus, suspended matter concentration and heavy metal content.

[0008] A segmented biological reactor realizes deep removal of nitrogen and phosphorus and efficient biological treatment by flexibly adjusting the reaction conditions of each segment.

[0009] An intelligent flocculation control module automatically and accurately adjusts the flocculant dosage, and realizes stable effluent water quality and reduces reagent consumption by combining efficient inclined tube sedimentation and sludge concentration integrated operation.

[0010] An ultrafiltration membrane biological reactor effectively removes residual suspended solids and colloids, and ensures long-term stable effluent by ozone catalytic oxidation synergy.

[0011] A sludge treatment module realizes collaborative optimization management of sludge reduction, resource utilization and energy recycling.

[0012] Further, the intelligent water quality detection module includes a multi-spectral ultraviolet-visible light online detector, an electrochemical sensor array, a turbidity laser scattering detector and an ion selective electrode detection unit, wherein: the multi-spectral ultraviolet-visible light online detector constructs a rapid prediction model of COD and BOD by collecting spectral absorption values at three characteristic wavelengths of 254 nm, 280 nm and 365 nm, realizes continuous monitoring every 30 seconds, and realizes continuous monitoring every 30 seconds; the electrochemical sensor array adopts a multi-electrode parallel configuration, including a dissolved oxygen electrode, a pH composite electrode, an ammonia nitrogen ion selective electrode and a total phosphorus photometric detection electrode, and maintains detection accuracy by temperature compensation and baseline drift correction, with an ammonia nitrogen detection accuracy of ±0.1 mg / L and a total phosphorus detection accuracy of ±0.01 mg / L; the turbidity laser scattering detector is designed based on a 90-degree scattered light detection principle, and is equipped with a self-cleaning device to prevent sensor surface contamination, with a suspended matter concentration detection range of 0-4000 mg / L; the ion selective electrode detection unit is used for heavy metal ion detection, and is configured with five heavy metal special electrodes of copper, zinc, cadmium, lead and mercury, with a detection lower limit of less than 0.01 mg / L.

[0013] Further, the segmented biological reactor adopts a three-stage A / O / A process configuration, wherein: the first anoxic segment is 30% of the total reactor length, the aerobic segment is 40%, and the second anoxic segment is 30%, with adjustable baffles arranged between each segment to realize flexible control of hydraulic retention time.

[0014] Further, the ultrafiltration membrane bioreactor adopts an external MBR configuration, selects a PVDF hollow fiber membrane with a pore size of 0.01-0.02 μm, a design value of membrane flux of 15-25 L / (m 2 ·h·bar), and a transmembrane pressure difference controlled within 0.1-0.3 bar; is divided into an aerobic zone and a membrane separation zone, the DO concentration in the aerobic zone is maintained at 4-6 mg / L, the MLSS concentration is controlled at 8000-12000 mg / L, the sludge age is set to 15-25 days, and the food microbe ratio is controlled at 0.05-0.15 kg BOD / (kg MLSS·d); the membrane cleaning adopts a strategy combining physical cleaning and chemical cleaning, the physical cleaning includes backwashing and aeration scrubbing, the backwashing is performed every 20-30 minutes, the backwashing time is 30-60 seconds, the backwashing intensity is 2-3 times the normal flux, and the gas-water ratio of the aeration scrubbing is 20:1-30:1; the chemical cleaning is divided into online chemical cleaning and offline chemical cleaning, the online chemical cleaning uses 0.2%-0.5% sodium hypochlorite solution and is performed every 24-48 hours, the offline chemical cleaning uses 0.5%-1.0% citric acid and 0.2%-0.5% sodium hydroxide alternately and is performed every 2-4 weeks, so as to ensure long-term stability of the membrane flux and a service life of the membrane of 3-5 years.

[0015] The application also aims to provide a method for classified sewage treatment, which is realized based on the above-mentioned system for classified sewage treatment and comprises the following steps:

[0016] Real-time water quality parameter data of the influent are acquired, including COD, BOD, ammonia nitrogen, total phosphorus, suspended substance concentration and heavy metal content, and an initial operation state of the intelligent sewage treatment system is acquired;

[0017] Intelligent grading treatment is performed according to the real-time water quality parameter data, the pollution degree of the influent is divided into three grades of slight pollution, moderate pollution and severe pollution, and the processing priority of each grade is determined in combination with the type characteristics of the pollutants, so as to generate a pretreatment process path of the intelligent sewage treatment system;

[0018] The intelligent sewage treatment system is controlled to start the corresponding pretreatment units in sequence according to the pretreatment process path, and automatically match the corresponding nutrition optimization strategy;

[0019] Whenever the influent reaches a pretreatment unit, the sewage in the current processing stage is marked as target processing sewage, and the reaction strategy of the segmented bioreactor is configured based on the pollution grade and the pollutant composition of the target processing sewage;

[0020] According to the reaction strategy, the segmented biological reactor is started, the modified carrier is used in cooperation with the biofilm and activated sludge to biologically remove nitrogen and phosphorus from the target sewage, and an independent anaerobic phosphorus release unit and a side flow chemical phosphorus removal unit are started to achieve enhanced phosphorus removal.

[0021] In the biological treatment process, the effluent water quality parameters of the target sewage are monitored in real time by the water quality intelligent detection module, the real-time operation data of the flocculation reaction are collected by the intelligent flocculation control module, and whether the flocculation dosage meets the preset treatment standard is judged in combination with the effluent water quality parameters and the real-time operation data.

[0022] If the flocculation treatment does not meet the preset standard, the fuzzy control is used to accurately adjust the composite flocculant dosage, and the high-efficiency inclined tube settler and sludge concentration integrated operation are maintained until the treatment standard is met.

[0023] If the flocculation treatment has met the preset standard, the ultrafiltration membrane biological reactor is started to separate the sewage after biological treatment and flocculation sedimentation by membrane, so as to remove residual suspended solids and colloidal substances.

[0024] At the same time, the ozone catalytic oxidation unit is started to perform advanced oxidation treatment on the refractory organic matter, and the effluent water quality is ensured to be stable and meet the surface water Class IV standard through the synergistic effect of membrane separation and catalytic oxidation.

[0025] The residual sludge generated in the treatment process is transported to the sludge treatment module, the anaerobic digestion unit is started to perform anaerobic fermentation treatment on the sludge, and the generated biogas is recovered for plant heating;

[0026] The sludge residue after anaerobic digestion is subjected to aerobic composting treatment, so as to realize sludge reduction and conversion into organic fertilizer, and complete the dual optimization of sludge treatment and energy utilization.

[0027] The running state and effluent water quality of the entire treatment system are monitored, if the system runs normally and the effluent meets the standard, the current running mode is maintained, if abnormal conditions are detected, the running parameters of the corresponding treatment unit are automatically adjusted, and the intelligent sewage treatment system is controlled to continue to treat the subsequent influent according to the optimized process path.

[0028] Further, the determination criteria of the intelligent hierarchical treatment are: when COD≤150 mg / L, BOD5≤50 mg / L, ammonia nitrogen≤15 mg / L, total phosphorus≤1.5 mg / L, suspended solids≤80 mg / L and the content of heavy metals is lower than the first level standard of the Integrated Wastewater Discharge Standard, it is determined as light pollution; when COD is in the range of 151-400 mg / L, BOD5 is in the range of 51-150 mg / L, ammonia nitrogen is in the range of 16-45 mg / L, total phosphorus is in the range of 1.6-4.0 mg / L, suspended solids is in the range of 81-200 mg / L, or there is a single heavy metal exceeding the standard but the overall does not exceed the second level standard of the Integrated Wastewater Discharge Standard, it is determined as moderate pollution; when any of the above indexes exceeds the moderate pollution threshold, or there is a serious heavy metal exceeding the standard, it is determined as severe pollution.

[0029] Further, the determination of the processing priority includes the following steps:

[0030] Detect and analyze various pollutants in the influent, obtain toxicity coefficient, biological degradation difficulty coefficient and processing cost coefficient as comprehensive evaluation factors, and construct a multi-objective optimization model considering treatment effect, treatment time and operation cost;

[0031] According to the type of pollutants, set the preliminary priority: the priority of heavy metal pollution is the highest, the priority of nitrogen and phosphorus nutrient pollution is the second, and the priority of organic matter pollution is relatively low, forming a preliminary sorting framework;

[0032] Integrate the processing time requirement and energy consumption cost of various pollutants, introduce time window and energy consumption factors into the optimization model, and provide basis for dynamic adjustment of priority;

[0033] According to the real-time operating conditions and processing targets, the relative weights of toxicity coefficient, biological degradation difficulty coefficient and processing cost coefficient are adjusted by using dynamic weight distribution method, so that the attention degree of the model to each index is adjusted with the change of working condition;

[0034] Combined with the multi-objective optimization model and the dynamic weight distribution result, the processing order of each pollutant is intelligently sorted, and the final processing priority list is generated, so as to realize the optimal balance among treatment effect, treatment time and operation cost.

[0035] Further, the generation of the pretreatment process path includes the following steps:

[0036] According to the pollution level and the type of pollutants of the influent, the corresponding basic process combination is selected from the preset process path library;

[0037] Based on the current system load state, the operation efficiency and maintenance state of each processing unit, the basic process combination is dynamically adjusted to form a pretreatment path meeting the real-time working condition;

[0038] Considering the influence of seasonal factors and temperature changes on the efficiency of biological treatment, the process parameters of each treatment unit are compensated and adjusted to maintain the stability of the treatment;

[0039] Based on historical treatment data and intelligent prediction analysis methods, the process path is optimized and predicted to generate a detailed process path including the start-up sequence of the treatment units, the residence time of each stage and the set values of the key control parameters;

[0040] According to the pollution level, the corresponding nutrient addition strategy is formulated: for light pollution, low nutrient addition mode is adopted to supplement trace elements and growth factors; for moderate pollution, balanced nutrient addition mode is adopted to supplement nutrient source according to the ratio of C:N:P=100:5:1; for severe pollution, intensified nutrient addition mode is adopted, the ratio of nitrogen and phosphorus is increased to C:N:P=100:8:1.5, and special enzyme preparations and biological catalysts are added to improve the treatment efficiency.

[0041] Further, the modified carrier is made of polyurethane sponge and is treated by surface modification to graft hydrophilic functional groups on the surface and load nutrient slow-release microspheres, so as to form a carrier structure with high specific surface area and good hydrophilicity, and the carrier density is 20-25 kg / m 3 , the specific surface area reaches 800-1000 m 2 / m 3 , and the porosity is more than 95%;

[0042] The composite flocculant is prepared by mixing polyaluminum chloride, cationic polyacrylamide and natural polymer flocculant according to a mass ratio of 6:2:1.

[0043] Further, the fuzzy control establishes a control rule base with the input variables of influent turbidity, pH value, conductivity and temperature and the output variable of flocculant dosage, contains 125 control rules, realizes accurate control of flocculant dosage through membership function design and optimization of inference rules, the dosage accuracy reaches ±2%, the response time is less than 30 seconds, and the stability and economy of the flocculation process are ensured.

[0044] Compared with the prior art, the present application has the following beneficial effects: through the combination of multi-parameter high-precision online monitoring, intelligent hierarchical decision and multi-unit collaborative treatment, the dynamic process path optimization, accurate dosing and deep purification treatment of different pollution grade sewage are realized, so as to significantly improve the stable standard rate of effluent and reduce the operating energy consumption and reagent consumption. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 A flowchart of a method for classified sewage treatment disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0046] For the purposes of making the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. Identical or similar reference numerals in the drawings represent identical or similar elements or elements with identical or similar functions throughout. The described embodiments are part of the embodiments of the present application, rather than all the embodiments.

[0047] All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor fall within the scope of protection of the present application.

[0048] The embodiments described below with reference to the drawings and the directional words are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0049] A system for classified sewage treatment, comprising the following components:

[0050] An intelligent water quality detection module for real-time and accurate monitoring of COD, BOD, ammonia nitrogen, total phosphorus, suspended matter concentration and heavy metal content;

[0051] A segmented biological reactor for deep removal of nitrogen and phosphorus and efficient biological treatment by flexible adjustment of reaction conditions in each segment;

[0052] An intelligent flocculation control module for automatic and accurate adjustment of flocculant dosage, combined with efficient inclined tube sedimentation and sludge concentration integrated operation, to realize stable effluent quality and reduce reagent consumption;

[0053] An ultrafiltration membrane biological reactor for effective removal of residual suspended matter and colloids, and through the synergistic effect of ozone catalytic oxidation, to ensure long-term stable effluent;

[0054] A sludge treatment module for collaborative optimization management of sludge reduction, resource utilization and energy recycling.

[0055] In summary, the system for classified sewage treatment realizes efficient removal of organic matter, nitrogen, phosphorus and heavy metals in sewage through multi-parameter real-time monitoring and accurate control. The collaborative work of the biological reactor and the flocculation and sedimentation unit significantly improves the stability of the effluent quality and reduces reagent consumption. The combination of ultrafiltration membrane and ozone catalytic oxidation ensures long-term compliance of the effluent. At the same time, the sludge treatment module realizes reduction, resource utilization and energy recycling, effectively improving the overall efficiency and economy of sewage treatment.

[0056] Further, the water quality intelligent detection module comprises a multi-spectrum ultraviolet-visible light on-line detector, an electrochemical sensor array, a turbidity laser scattering detector and an ion selective electrode detection unit, wherein: the multi-spectrum ultraviolet-visible light on-line detector acquires spectral absorption values at three characteristic wavelengths of 254 nm, 280 nm and 365 nm to construct a rapid prediction model of COD and BOD, and realizes continuous monitoring every 30 seconds; the electrochemical sensor array adopts a multi-electrode parallel configuration, comprises a dissolved oxygen electrode, a pH composite electrode, an ammonia nitrogen ion selective electrode and a total phosphorus photometric detection electrode, and realizes detection accuracy through temperature compensation and baseline drift correction, with an ammonia nitrogen detection accuracy of ±0.1 mg / L and a total phosphorus detection accuracy of ±0.01 mg / L; the turbidity laser scattering detector is designed based on a 90-degree scattered light detection principle, and is equipped with a self-cleaning device to prevent sensor surface pollution, with a suspended solids concentration detection range of 0-4000 mg / L; and the ion selective electrode detection unit is used for heavy metal ion detection, and is configured with five heavy metal special electrodes of copper, zinc, cadmium, lead and mercury, with a detection lower limit of less than 0.01 mg / L.

[0057] As described above, through comprehensive application of multi-spectrum on-line detection, electrochemical sensing, multi-angle laser scattering and heavy metal ion selective electrode, high-precision, rapid and continuous monitoring of COD, BOD, ammonia nitrogen, total phosphorus, suspended solids and heavy metals is realized, and real-time grasping of key parameters in the sewage treatment process is effectively ensured, thereby providing a reliable basis for accurate control of subsequent treatment units and stable effluent water quality.

[0058] Further, the segmented biological reactor adopts a three-stage A / O / A process configuration, wherein: the first anoxic section accounts for 30% of the total reactor length, the aerobic section accounts for 40%, and the second anoxic section accounts for 30%, and adjustable baffles are arranged between the sections to realize flexible control of hydraulic retention time.

[0059] As described above, through the three-stage A / O / A process layout and adjustable baffles to realize flexible control of hydraulic retention time, the sewage is subjected to targeted anoxic and aerobic treatment in different reaction sections, thereby significantly improving nitrogen and phosphorus removal efficiency and overall biological treatment effect, and ensuring stable effluent water quality and adaptation to inflow load fluctuations.

[0060] Further, the ultrafiltration membrane biological reactor adopts an external MBR configuration, and a PVDF hollow fiber membrane with a pore size of 0.01-0.02 μm is selected, with a design value of membrane flux of 15-25 L / (m 2·h·bar), the trans-membrane pressure difference is controlled in the range of 0.1-0.3 bar; the aerobic zone and the membrane separation zone are divided, the DO concentration is maintained in the range of 4-6 mg / L, the MLSS concentration is controlled in the range of 8000-12000 mg / L, the sludge age is set to be 15-25 days, and the food-microbe ratio is controlled in the range of 0.05-0.15 kg BOD / (kg MLSS·d); the physical cleaning and the chemical cleaning are combined to clean the membrane, the physical cleaning includes the backwashing and the aeration scrubbing, the backwashing is performed every 20-30 minutes, the backwashing time is 30-60 seconds, the backwashing intensity is 2-3 times of the normal flux, and the gas-water ratio of the aeration scrubbing is 20:1-30:1; the chemical cleaning is divided into the online chemical cleaning and the offline chemical cleaning, the online chemical cleaning uses 0.2%-0.5% sodium hypochlorite solution, and is performed every 24-48 hours, the offline chemical cleaning uses 0.5%-1.0% citric acid and 0.2%-0.5% sodium hydroxide alternately, and is performed every 2-4 weeks, so as to ensure the long-term stability of the membrane flux and the service life of the membrane to be 3-5 years.

[0061] According to the above, the residual suspended solids and colloids are removed efficiently by the external MBR configuration and the PVDF hollow fiber membrane, the DO, the MLSS and the sludge age are controlled in the aerobic zone, the stable cooperation between the biological treatment and the membrane separation is realized, the physical and chemical cleaning strategies are combined to ensure the long-term stability of the membrane flux, the service life of the membrane is effectively prolonged, and the effluent quality is ensured to be continuously up to the standard.

[0062] Further, the sludge treatment module comprises a sludge pretreatment unit, an anaerobic digestion unit, a biogas collection and purification unit, a sludge dewatering unit and an aerobic composting unit, wherein:

[0063] The sludge pretreatment unit firstly adopts gravity concentration, and the sludge is kept in the concentration tank for 12-24 hours, so that the water content is reduced to 95%-96%; then the sludge is subjected to mechanical concentration by a belt thickener, so that the water content is further reduced to 92%-94%;

[0064] The anaerobic digestion unit adopts a mesophilic anaerobic digestion process, the digestion temperature is controlled to be 35±2℃, the effective volume of the digestion tank is designed according to the sludge retention time of 15-20 days, the organic load is controlled to be 1.5-2.5 kg VS / (m 3 ·d), the pH value is maintained in the range of 6.8-7.2, and the alkalinity is controlled to be 2000-4000 mg / L; the digestion process is divided into an acidification stage of 2-3 days, a gas production stage of 8-12 days and a stable stage of 5-7 days, the feeding amount and the stirring intensity are adjusted by monitoring the volatile fatty acid concentration, the pH value change and the gas production amount;

[0065] The biogas collection and purification unit comprises a gas-liquid separator, a desulfurization device, a dehydration device and a gas storage device, the gas-liquid separator adopts a combination of gravity separation and cyclone separation to remove water and impurities in the biogas; the desulfurization device adopts a dry desulfurization process, the desulfurizer is selected as iron oxide desulfurizer, the desulfurization tower is filled with a height of 2-3 m, and the gas residence time is 8-15 seconds; the dehydration device adopts a combination of condensation dehydration and adsorption dehydration, the condensation temperature is controlled at 4-8℃, and the adsorbent is selected as molecular sieve or silica gel;

[0066] The aerobic composting unit adopts a forced ventilation static composting process, the composting raw materials include anaerobic digestion sludge, wood chips and rice husk, the volume ratio is 6:3:1, the moisture content is adjusted to 55%-60%, and the carbon-nitrogen ratio is adjusted to 25-30:1; the aerobic composting unit is a closed composting workshop, equipped with an automatic turning machine and a forced ventilation system, the ventilation volume is 0.1-0.3 m 3 / (kg·min), the ventilation mode adopts intermittent ventilation, the ventilation time to the stop time ratio is 1:2-1:3; the composting process is divided into a temperature rising period (3-5 days, the temperature rises to 50-60℃), a high temperature period (15-20 days, the temperature is maintained at 60-70℃), a temperature falling period (10-15 days, the temperature falls to 40-50℃) and a maturation period (7-10 days, the temperature is stable at 30-40℃); temperature monitoring adopts a multi-point temperature sensor, 3-5 monitoring points are arranged per cubic meter of the pile, the ventilation volume or the turning frequency is increased when the temperature is too high, and the ventilation volume is reduced or easily degradable organic matter is added when the temperature is insufficient; the composting period is 45-60 days, after maturation, the moisture content of the sludge is reduced to below 30%, the organic matter content reaches 30%-40%, the humic acid content reaches more than 15%, and the heavy metal content meets the standard requirements of "Sludge for Disposal of Municipal Wastewater Treatment Plant for Garden Greening".

[0067] Therefore, the sludge moisture content is reduced through gravity and mechanical concentration, the organic matter is decomposed and biogas is produced through mesophilic anaerobic digestion, the stable use of biogas is ensured by the biogas collection and purification unit, the digestion residue is converted into mature organic fertilizer through temperature control ventilation and turning treatment in the aerobic composting unit, the sludge is reduced, stabilized, recycled and energy is recovered, and meanwhile, the moisture, organic matter, humic acid and heavy metal contents of the treated sludge meet the relevant discharge standards.

[0068] As shown in Figure 1 The application further provides a method for classified sewage treatment, which is used for the above-mentioned system for classified sewage treatment, and comprises the following steps:

[0069] Real-time water quality parameter data of the influent are acquired, including COD, BOD, ammonia nitrogen, total phosphorus, suspended matter concentration and heavy metal content, and the initial operation state of the intelligent sewage treatment system is acquired;

[0070] Intelligently grading processing according to the real-time water quality parameter data, the water pollution degree is divided into three levels of light pollution, moderate pollution and heavy pollution, and the processing priority of each level is determined combined with the characteristics of the pollutant type, to generate the pretreatment process path of the intelligent sewage treatment system;

[0071] The intelligent sewage treatment system is controlled to start the corresponding pretreatment unit according to the pretreatment process path, and automatically match the corresponding nutrient optimization strategy;

[0072] Whenever the influent reaches a pretreatment unit, the sewage of the current treatment stage is marked as target treatment sewage, and the reaction strategy of the segmented biological reactor is configured based on the pollution level and pollutant composition of the target treatment sewage;

[0073] According to the reaction strategy, the segmented biological reactor is started, and the target treatment sewage is biologically denitrified and phosphorus-removed by the synergistic effect of modified carrier and biofilm and activated sludge, and the independent anaerobic phosphorus release unit and the side flow chemical phosphorus removal unit are started to achieve enhanced phosphorus removal;

[0074] In the biological treatment process, the effluent water quality parameters of the target treatment sewage are monitored in real time by the water quality intelligent detection module, and the real-time operation data of the flocculation reaction are collected by the intelligent flocculation control module, and the flocculation dosage is judged whether it reaches the preset treatment standard combined with the effluent water quality parameters and the real-time operation data;

[0075] If the flocculation treatment does not reach the preset standard, the composite flocculant dosage is precisely adjusted by fuzzy control, and the high-efficiency inclined tube sedimentation and sludge concentration integrated operation is maintained until the treatment standard is reached;

[0076] If the flocculation treatment has reached the preset standard, the ultrafiltration membrane biological reactor is started to separate the sewage after biological treatment and flocculation sedimentation by membrane, to remove residual suspended solids and colloidal substances;

[0077] At the same time, the ozone catalytic oxidation unit is started to perform advanced oxidation treatment on the refractory organic matter, and the effluent water quality is ensured to be stable to reach the surface water IV standard through the synergistic effect of membrane separation and catalytic oxidation;

[0078] The residual sludge generated in the treatment process is transported to the sludge treatment module, the anaerobic digestion unit is started to perform anaerobic fermentation treatment on the sludge, and the generated biogas is recovered for plant heating;

[0079] The sludge residue after anaerobic digestion is subjected to aerobic composting treatment, realizing sludge reduction and conversion into organic fertilizer, and completing the double optimization of sludge treatment and energy utilization;

[0080] The running state of the whole treatment system and the effluent water quality are monitored, if the system runs normally and the effluent water meets the standard, the current running mode is maintained, if abnormal conditions are detected, the running parameters of the corresponding treatment unit are automatically adjusted, and the intelligent sewage treatment system is controlled to continue to treat the subsequent influent according to the optimized process path.

[0081] Through the method for classifying sewage treatment, different water qualities and different pollution levels of influent can be accurately, dynamically and hierarchically treated, thereby significantly improving the overall efficiency of sewage treatment and the stability of effluent water quality. First, by acquiring real-time water quality parameters of the influent, including COD, BOD, ammonia nitrogen, total phosphorus, suspended solids and heavy metal content, and combining the initial running state of the system, the characteristics of the influent are comprehensively mastered, providing a reliable basis for subsequent process selection and operation optimization. On this basis, the influent is intelligently hierarchically treated, the pollution degree is divided into light pollution, medium pollution and heavy pollution, and the treatment priority of each level is determined according to the characteristics of pollutants, and a pretreatment process path is generated, so that the most suitable treatment process can be automatically matched according to different influent characteristics, avoiding the problem of efficiency decline of traditional fixed process under load fluctuation or complex water quality, while ensuring the rational use of resources and reagents, reducing the operation cost.

[0082] After the sewage enters each pretreatment unit, the target treatment sewage is marked and the reaction strategy of the segmented biological reactor is configured based on the pollution level and the composition of pollutants, so that the reaction conditions of each segment are highly matched with the characteristics of the influent, realizing the deep removal of nitrogen, phosphorus and organic matter. The segmented biological reactor combines the synergistic effect of modified carrier, biofilm and activated sludge, so that the biological denitrification and phosphorus removal efficiency is significantly improved, and the linkage of the independent anaerobic phosphorus release unit and the side flow chemical phosphorus removal unit strengthens the phosphorus removal capacity, ensuring that the effluent can meet the standard stably under different water quality conditions. In the treatment process, the water quality intelligent detection module monitors the effluent water quality parameters in real time, and combines the flocculation operation data collected by the intelligent flocculation control module to accurately judge whether the dosage of composite flocculant meets the preset standard, thereby realizing accurate control and avoiding water quality fluctuations caused by excessive or insufficient dosage of reagents.

[0083] When the flocculation treatment does not meet the preset standards, the fuzzy control mechanism can finely adjust the composite flocculant dosage while maintaining the integrated operation of the high-efficiency inclined tube settler and the sludge concentration unit, ensuring that the effluent water quality quickly meets the expected indicators. When the treatment meets the standards, the ultrafiltration membrane bioreactor further removes residual suspended solids and colloidal substances, effectively ensuring the clarity and stability of the effluent, reducing the subsequent treatment load. At the same time, the ozone catalytic oxidation unit performs advanced oxidation on refractory organic matter, improving the long-term stability of the effluent water quality, enabling it to continuously meet the Class IV standard of surface water. Through the synergistic effect of membrane separation and catalytic oxidation, efficient removal of various pollutants can be achieved, especially in the face of sudden high-concentration pollution or complex industrial wastewater, while still maintaining stable treatment effects.

[0084] In the sludge treatment link, the method transports the excess sludge generated during the treatment process to the sludge treatment module, realizes organic matter decomposition and biogas recovery through the anaerobic digestion unit, and the biogas can be used for plant heating, improving energy utilization efficiency. Subsequently, the digestion residue is subjected to aerobic composting treatment, and by controlling the composting temperature, ventilation, and turning frequency, the sludge is converted into mature organic fertilizer, achieving sludge reduction, stabilization, and resource management. This treatment strategy not only reduces sludge emissions but also effectively reduces the risk of secondary pollution, while converting sludge into usable organic fertilizer, achieving dual improvement of economic and environmental benefits.

[0085] In addition, the method can automatically adjust the operating parameters of each treatment unit under abnormal conditions by real-time monitoring of system operation status and effluent water quality, enabling the intelligent wastewater treatment system to continuously process subsequent influent according to the optimized process path, ensuring stable operation under different loads and water quality fluctuations. This dynamic adjustment capability improves the adaptability and reliability of the system, avoiding the lag response of traditional fixed processes to water quality changes, thereby ensuring efficient, continuous, and safe operation of the entire wastewater treatment process.

[0086] In summary, the method for classified wastewater treatment can achieve the whole process optimization management from influent acquisition, intelligent grading, segmented biological reaction, precise flocculation control, ultrafiltration membrane advanced treatment, ozone advanced oxidation, to sludge anaerobic digestion and aerobic composting, ensuring long-term stable effluent, saving chemicals and energy, reducing sludge and resource utilization, and being able to cope with water quality fluctuations, complex pollutants, and system abnormalities, significantly improving the overall efficiency and environmental benefits of wastewater treatment.

[0087] Further, the determination criteria of the intelligent hierarchical treatment are: when COD≤150 mg / L, BOD5≤50 mg / L, ammonia nitrogen≤15 mg / L, total phosphorus≤1.5 mg / L, suspended solids≤80 mg / L and the content of heavy metals is lower than the first level standard of the “Integrated Wastewater Discharge Standard”, it is determined as light pollution; when COD is in the range of 151-400 mg / L, BOD5 is in the range of 51-150 mg / L, ammonia nitrogen is in the range of 16-45 mg / L, total phosphorus is in the range of 1.6-4.0 mg / L, suspended solids is in the range of 81-200 mg / L, or there is a single heavy metal exceeding the standard but the overall does not exceed the second level standard of the “Integrated Wastewater Discharge Standard”, it is determined as moderate pollution; when any of the above indicators exceeds the moderate pollution threshold, or there is a serious heavy metal exceeding the standard, it is determined as severe pollution.

[0088] Therefore, by quantitatively determining COD, BOD, ammonia nitrogen, total phosphorus, suspended solids and heavy metal content, the influent can be accurately divided into light, moderate and severe pollution, realizing the scientific classification of different pollution grade wastewater, providing reliable basis for subsequent treatment unit selection, process path optimization and operation strategy adjustment, ensuring that the treatment process can be flexibly adjusted according to the water quality characteristics, improving the wastewater treatment efficiency and water quality stability.

[0089] Further, the determination of the processing priority includes the following steps:

[0090] Detect and analyze various pollutants in the influent, obtain toxicity coefficient, biodegradation difficulty coefficient and processing cost coefficient as comprehensive evaluation factors, and construct a multi-objective optimization model considering treatment effect, treatment time and operation cost;

[0091] Set the preliminary priority according to the type of pollutants: the priority of heavy metal pollution is the highest, the priority of nitrogen and phosphorus nutrient pollution is the second, and the priority of organic matter pollution is relatively low, forming a preliminary ordering framework;

[0092] Introduce time window and energy consumption factors into the optimization model by comprehensively considering the processing time requirement and energy consumption cost of various pollutants, to provide basis for dynamic adjustment of priority;

[0093] According to the real-time operating conditions and processing targets, the relative weights of toxicity coefficient, biodegradation difficulty coefficient and processing cost coefficient are adjusted by using dynamic weight distribution method, so that the attention degree of the model to each index is adjusted with the change of working conditions;

[0094] The processing order of each pollutant is intelligently sorted by combining the multi-objective optimization model and the dynamic weight distribution result, to generate a final processing priority list, realizing the optimal balance between treatment effect, treatment time and operation cost.

[0095] From the above, by comprehensively analyzing the toxicity, biodegradation difficulty and treatment cost of the influent pollutants, a multi-objective optimization model is constructed and combined with dynamic weight distribution to realize scientific prioritization of different pollutants, so that the treatment time and operation cost can be considered while ensuring the treatment effect, dynamically adapting to real-time water quality changes, improving sewage treatment efficiency and resource utilization level, optimizing operation strategy, and ensuring stable and standard effluent water quality.

[0096] Further, the generation of the pretreatment process path includes the following steps:

[0097] According to the pollution level and pollutant type of the influent, the corresponding basic process combination is selected from the preset process path library;

[0098] Based on the current system load state, the operation efficiency and maintenance state of each treatment unit, the basic process combination is dynamically adjusted to form a pretreatment path that meets the real-time working condition;

[0099] Considering the influence of seasonal factors and temperature changes on biological treatment efficiency, the process parameters of each treatment unit are compensated and adjusted to maintain treatment stability;

[0100] Based on historical treatment data and intelligent prediction analysis method, the process path is optimized and predicted to generate a detailed process path including treatment unit start-up sequence, residence time of each stage and key control parameter setting value;

[0101] According to the pollution level, the corresponding nutrition adding strategy is formulated: for light pollution, low nutrition adding mode is adopted to supplement trace elements and growth factors; for moderate pollution, balanced nutrition adding mode is adopted to supplement nutrient source according to the ratio of C:N:P=100:5:1; for severe pollution, intensified nutrition adding mode is adopted, the ratio of nitrogen and phosphorus is increased to C:N:P=100:8:1.5, and special enzyme preparation and biological catalyst are added to improve the treatment efficiency.

[0102] From the above, by combining the influent pollution level, pollutant type, system load and operation state of each treatment unit, the basic process combination is selected and dynamically adjusted from the process path library, and the influence of seasonal and temperature factors on biological treatment efficiency is considered to realize fine compensation and optimization prediction of process parameters; by formulating a hierarchical nutrition adding strategy, pollutants of each pollution level can be efficiently removed under the premise of maintaining treatment stability, improving overall operation efficiency and reliability of effluent water quality.

[0103] Further, the reaction strategy of the segmented biological reactor includes:

[0104] When the influent is slightly polluted, the DO concentration is set to 2.0-3.0 mg / L, the MLSS concentration is set to 3000-4000 mg / L, and the hydraulic retention time is set to 8-10 hours;

[0105] When the influent is moderately polluted, the DO concentration is set to 3.0-4.0 mg / L, the MLSS concentration is set to 4000-6000 mg / L, and the hydraulic retention time is set to 10-14 hours;

[0106] When the influent is heavily polluted, the DO concentration is set to 4.0-5.0 mg / L, the MLSS concentration is set to 6000-8000 mg / L, and the hydraulic retention time is set to 14-18 hours, and the internal reflux and external reflux are started, wherein the internal reflux ratio is set to 200%-400%, and the external reflux ratio is set to 50%-100%, so as to ensure sufficient denitrification and nitrification.

[0107] Therefore, by accurately regulating the DO concentration, the MLSS concentration, and the hydraulic retention time according to the pollution level of the influent, and by starting the internal reflux and the external reflux to adjust the denitrification and the nitrification when the influent is heavily polluted, the nitrogen and phosphorus nutrients can be efficiently removed, the optimal nitrogen and phosphorus removal effect can be achieved in the biological treatment of wastewater with different pollution levels, the treatment efficiency and the water quality stability are improved, and the water quality fluctuation and the operation load change can be effectively adapted.

[0108] Further, the modified carrier is made of polyurethane sponge and is treated by surface modification to graft hydrophilic functional groups and load nutrient slow-release microspheres on the surface, so as to form a carrier structure with high specific surface area and good hydrophilicity, and the carrier density is 20-25 kg / m 3 , the specific surface area reaches 800-1000 m 2 / m 3 , and the porosity is more than 95%.

[0109] Therefore, by surface modification of the polyurethane sponge and loading of the nutrient slow-release microspheres, a porous structure with high specific surface area and good hydrophilicity is formed, the microbial adhesion and the biofilm formation are more uniform and stable, the microbial community activity in the biological reactor is enhanced, the nitrogen and phosphorus removal efficiency is improved, the water flow distribution and the material transfer are optimized, and the reaction is sufficient and the water quality is stable and reliable in the biological treatment of wastewater.

[0110] Further, the composite flocculant is prepared by mixing polyaluminum chloride, cationic polyacrylamide, and natural polymer flocculant at a mass ratio of 6:2:1.

[0111] From the above, by reasonably matching polyaluminum chloride, cationic polyacrylamide and natural polymer flocculants, the flocculation and sedimentation performance is enhanced, the suspended solids, colloidal particles and part of the dissolved pollutants are efficiently removed, the sludge settling velocity and concentration efficiency are improved, the reagent consumption is reduced, the effluent turbidity and water quality stability are ensured, and the operation effect of the subsequent biological treatment and membrane separation unit is optimized.

[0112] Further, the independent anaerobic phosphorus release unit adopts an upflow anaerobic sludge bed reactor, the effective volume is 15% to 20% of the volume of the main biological reactor, biological carrier fillers are arranged inside to improve the sludge concentration, the dissolved oxygen concentration is controlled below 0.2 mg / L under anaerobic environment, the temperature is controlled within the range of 25 to 30°C, the hydraulic retention time is set to 2 to 4 hours, and the phosphorus release process of polyphosphorus bacteria is promoted by adding easily degradable organic carbon source.

[0113] From the above, by combining the upflow anaerobic sludge bed reactor with the biological carrier fillers, under the conditions of low dissolved oxygen and suitable temperature, the phosphorus release of polyphosphorus bacteria is significantly promoted by controlling the hydraulic retention time and adding easily degradable organic carbon source, the phosphorus removal efficiency in the anaerobic stage is improved, a stable raw material basis is provided for the subsequent biological treatment unit for enhanced phosphorus removal, and the nitrogen and phosphorus removal capacity of the overall wastewater treatment system is optimized.

[0114] Further, the side-flow chemical phosphorus removal unit adopts a coagulation and sedimentation process, the selected chemical phosphorus removal agent is polyaluminum ferric chloride or ferrous sulfate, the dosage is automatically adjusted according to the total phosphorus concentration of the influent at a molar ratio of 1.5 to 2.0:1, the reaction time is set to 15 to 20 minutes, and the sedimentation time is set to 30 to 45 minutes.

[0115] From the above, by the coagulation and sedimentation process and the accurate addition of the chemical phosphorus removal agent, the dosage is automatically adjusted according to the total phosphorus concentration of the influent, the reaction and sedimentation time is reasonably set, the phosphorus is efficiently removed by sedimentation, the total phosphorus concentration of the effluent is significantly reduced, the water quality stability is improved, the load of the subsequent treatment unit is reduced, the overall phosphorus removal capacity and operation reliability are enhanced.

[0116] Further, the high-efficiency inclined tube settler adopts honeycomb-shaped inclined tube fillers, the inclined tube length is 1.0 to 1.2 m, the inclination angle is 60°, the inclined tube aperture is 80 to 100 mm, the material is polypropylene corrosion-resistant material, the upward flow velocity in the inclined tube sedimentation zone is controlled at 0.5 to 0.8 mm / s, the surface hydraulic load is 4 to 6 m 3 / (m 2h); the sludge concentration integrated operation is realized by setting a conical sludge concentration area at the bottom of the settler, the slope of the concentration area is 45°-50°, equipped with slow stirring device to prevent sludge hardening, the stirring speed is 1-2 r / min, the concentration time is 2-4 hours, the moisture content of the sludge after concentration is reduced to 96%-97%; the settler is equipped with surface slag scraper and sludge scraper, the linear speed of the slag scraper is 1-2 m / min, the linear speed of the sludge scraper is 0.5-1 m / min, to ensure the timely removal of floating slag and settled mud; the effluent water adopts tooth-shaped triangular weir water distribution, the weir load is controlled at 1.5-2.0 L / (s·m), the effluent suspended solids concentration is controlled below 10 mg / L, the turbidity is controlled below 5 NTU, to provide stable water quality conditions for subsequent membrane treatment.

[0117] Therefore, by designing the honeycomb-shaped inclined pipe filler, reasonably setting the length and inclination angle of the inclined pipe, and controlling the rising flow rate and surface hydraulic load, efficient sedimentation of suspended solids is realized; by combining the bottom conical concentration area and slow stirring device, effective concentration of sludge and prevention of hardening are realized; by cooperating the slag scraper and sludge scraper, floating slag and settled mud are timely removed; by using the tooth-shaped triangular weir to evenly distribute the supernatant, the effluent suspended solids concentration and turbidity are effectively controlled, stable water quality is provided for subsequent membrane treatment, and the efficiency of precipitation and sludge concentration is significantly improved.

[0118] Further, the catalyst of the ozone catalytic oxidation unit is a supported iron-manganese composite oxide catalyst, the carrier is α-Al2O3 porous ceramic, the specific surface area is 200-300 m 2 / g, the active component content is 8-12 wt% of Fe2O3 and 4-8 wt% of MnO2; the ozone generator is a high-frequency discharge type ozone generator, the ozone production is 10-50 g / h adjustable, the ozone concentration is 80-150 mg / L, and the dosage is automatically adjusted according to the influent COD concentration at a mass ratio of 1.5-2.5:1.

[0119] Therefore, by the synergistic effect of the supported iron-manganese composite oxide catalyst and the porous ceramic carrier, the catalytic oxidation efficiency of ozone on refractory organic matter is improved; by combining the high-frequency discharge type ozone generator with adjustable ozone production and concentration, and automatically adjusting the dosage according to the influent COD concentration, efficient removal of organic pollutants is realized, and the water quality stability and treatment reliability of the effluent are significantly improved.

[0120] Further, the fuzzy control establishes a control rule base with influent turbidity, pH value, conductivity, and temperature as input variables and flocculant dosage as output variable, contains 125 control rules, realizes precise control of flocculant dosage through membership function design and optimization of inference rules, the dosing accuracy reaches ±2%, the response time is less than 30 seconds, and the stability and economy of the flocculation process are ensured.

[0121] From the above, by taking the turbidity, pH value, conductivity and temperature of the influent as input variables, and taking the flocculant dosage as the output variable, relying on the rule base containing 125 control rules, combining the optimized membership function and reasoning mechanism, the high-precision flocculant dosage is realized, the dosage accuracy can reach ±2%, the response time is less than 30 seconds, so as to ensure the stability of the flocculation process, and effectively reduce the consumption of reagents and improve the operation economy.

[0122] Further, the automatic adjustment of the operating parameters comprises the following steps:

[0123] Real-time acquisition of key control variables of each reaction tank, including aeration quantity, reflux ratio, sludge reflux quantity, flocculant dosage, membrane flux and ozone dosage, and controlled variables of each treatment unit, to provide basic data for abnormality judgment;

[0124] Based on the model predictive control method, a dynamic mathematical model between the influent water quality parameters, treatment process parameters and effluent water quality indicators is constructed, which is used to establish the data benchmark of normal system operation;

[0125] The adjustment range of the key control variables is set, and the equipment operation safety constraint, process stability constraint and effluent water quality constraint are established, to ensure that the parameter adjustment process will not cause system instability or equipment damage;

[0126] The rolling optimization strategy is used for online prediction and control, the prediction time domain is set to 24 hours, the control time domain is 4 hours, and the sampling time is 15 minutes, and the optimal control sequence is obtained by online optimization solution and implemented.

[0127] From the above, by real-time acquisition of key control variables of each reaction tank, including aeration quantity, reflux ratio, sludge reflux quantity, flocculant dosage, membrane flux and ozone dosage, and controlled variables of each treatment unit, a dynamic mathematical model between the influent water quality, process parameters and effluent indicators is established, to realize the construction of system operation data benchmark; under the premise of ensuring equipment safety, process stability and effluent water quality meeting the standards, according to the rolling optimization strategy, the key parameters are online predicted and controlled, 24 hours of prediction time domain and 4 hours of control time domain, 15 minutes of sampling interval are adopted, the dynamic optimization adjustment of each treatment unit parameter is realized, so as to ensure the stable and efficient operation of the system and the continuous standard of the effluent water quality.

[0128] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A system for treating classified wastewater, characterized in that, Includes the following components: The intelligent water quality monitoring module is used to monitor COD, BOD, ammonia nitrogen, total phosphorus, suspended solids concentration and heavy metal content in real time and with precision. Segmented bioreactors achieve deep removal and efficient biological treatment of nitrogen and phosphorus by flexibly adjusting the reaction conditions of each segment. The intelligent flocculation control module automatically and precisely adjusts the flocculant dosage, and combines it with the integrated operation of high-efficiency inclined tube sedimentation and sludge thickening to achieve stable effluent quality and reduce chemical consumption. Ultrafiltration membrane bioreactors effectively remove residual suspended solids and colloids, and through the synergistic effect of ozone catalytic oxidation, ensure that the effluent meets standards in the long term. The sludge treatment module enables coordinated and optimized management of sludge reduction, resource utilization, and energy recovery.

2. The system for classified wastewater treatment according to claim 1, characterized in that, The intelligent water quality detection module includes a multispectral ultraviolet-visible online detector, an electrochemical sensor array, a turbidity laser scattering detector, and an ion-selective electrode detection unit. Specifically, the multispectral ultraviolet-visible online detector acquires spectral absorption values ​​at three characteristic wavelengths (254 nm, 280 nm, and 365 nm) to construct a rapid prediction model for COD and BOD, achieving continuous monitoring every 30 seconds. The electrochemical sensor array employs a multi-electrode parallel configuration, including a dissolved oxygen electrode, a pH composite electrode, and an ammonia nitrogen ionization electrode. The system includes ion-selective electrodes and total phosphorus detection electrodes, with temperature compensation and baseline drift correction to ensure detection accuracy. The accuracy for ammonia nitrogen detection is ±0.1 mg / L, and the accuracy for total phosphorus detection is ±0.01 mg / L. The turbidity laser scattering detector is designed based on the 90-degree scattered light detection principle and is equipped with a self-cleaning device to prevent sensor surface contamination. The detection range for suspended solids concentration is 0–4000 mg / L. The ion-selective electrode detection unit is used for heavy metal ion detection and is equipped with dedicated electrodes for five heavy metals: copper, zinc, cadmium, lead, and mercury. The detection limits for all five heavy metals are below 0.01 mg / L.

3. A system for treating classified wastewater according to claim 1, characterized in that, The segmented bioreactor adopts a three-stage A / O / A process configuration, wherein: the first anoxic section accounts for 30% of the total reactor length, the aerobic section accounts for 40%, the second anoxic section accounts for 30%, and adjustable baffles are set between each section to achieve flexible control of hydraulic retention time.

4. A system for classifying and treating wastewater according to claim 1, characterized in that, The ultrafiltration membrane bioreactor adopts an external MBR configuration, using PVDF hollow fiber membranes with a pore size of 0.01–0.02 μm and a membrane flux design value of 15–25 L / (m²). 2 The membrane pressure differential is controlled within the range of 0.1–0.3 bar (·h·bar); it is divided into an aerobic zone and a membrane separation zone. In the aerobic zone, the DO concentration is maintained at 4–6 mg / L, the MLSS concentration is controlled at 8000–12000 mg / L, the sludge age is set at 15–25 days, and the feed-to-microbe ratio is controlled at 0.05–0.15 kg BOD / (kg MLSS·d); a combination of physical and chemical cleaning strategies is used for membrane cleaning. Physical cleaning includes backwashing and aeration scrubbing, with backwashing every 20–30 minutes. Perform one backflushing cycle, with a backflushing time of 30–60 seconds and a backflushing intensity of 2–3 times the normal flux. The air-to-water ratio for aeration and scrubbing should be 20:1–30:

1. Chemical cleaning is divided into online chemical cleaning and offline chemical cleaning. Online chemical cleaning uses a 0.2%–0.5% sodium hypochlorite solution and is performed every 24–48 hours. Offline chemical cleaning uses alternating cleaning with 0.5%–1.0% citric acid and 0.2%–0.5% sodium hydroxide and is performed every 2–4 weeks to ensure long-term stability of membrane flux and a membrane service life of 3–5 years.

5. A method for treating classified wastewater, implemented based on a system for treating classified wastewater as described in any one of claims 1-4, characterized in that, Includes the following steps: The system acquires real-time water quality parameters of the influent, including COD, BOD, ammonia nitrogen, total phosphorus, suspended solids concentration, and heavy metal content, and obtains the initial operating status of the intelligent wastewater treatment system. Based on the real-time water quality parameter data, intelligent classification processing is performed to divide the influent pollution level into three levels: light pollution, moderate pollution, and heavy pollution. The treatment priority of each level is determined in combination with the characteristics of pollutant type, and the pretreatment process path of the intelligent sewage treatment system is generated. The intelligent wastewater treatment system is controlled to sequentially start the corresponding pretreatment units according to the pretreatment process path, and automatically match the corresponding nutrient optimization strategy. Whenever the influent reaches a pretreatment unit, the wastewater in the current treatment stage is marked as the target wastewater, and the reaction strategy of the segmented bioreactor is configured based on the pollution level and pollutant composition of the target wastewater. The segmented bioreactor is started according to the reaction strategy described above. The modified carrier, biofilm and activated sludge are used to carry out biological denitrification and phosphorus removal treatment on the target wastewater. At the same time, the independent anaerobic phosphorus release unit and the side-flow chemical phosphorus removal unit are started to achieve enhanced phosphorus removal. During the biological treatment process, the water quality parameters of the target wastewater are monitored in real time by the intelligent water quality detection module, and the real-time operation data of the flocculation reaction is collected by the intelligent flocculation control module. The effluent water quality parameters and the real-time operation data are combined to determine whether the flocculation addition has reached the preset treatment standard. If the flocculation treatment fails to meet the preset standard, fuzzy control is used to precisely adjust the dosage of composite flocculant and maintain the integrated operation of the high-efficiency inclined tube sedimentation tank and sludge thickening until the treatment standard is met. If the flocculation treatment has reached the preset standard, the ultrafiltration membrane bioreactor is started to perform membrane separation on the wastewater after biological treatment and flocculation sedimentation to remove residual suspended solids and colloidal substances. At the same time, the ozone catalytic oxidation unit is activated to carry out advanced oxidation treatment of recalcitrant organic matter. Through the synergistic effect of membrane separation and catalytic oxidation, the effluent quality is ensured to stably meet the Class IV surface water standard. The remaining sludge generated during the treatment process is transported to the sludge treatment module, and the anaerobic digestion unit is started to carry out anaerobic fermentation treatment of the sludge, and the biogas generated is recovered for heating in the plant area. Aerobic composting of sludge residue after anaerobic digestion reduces sludge volume and converts it into organic fertilizer, achieving dual optimization of sludge treatment and energy utilization. The system monitors the operating status and effluent quality of the entire treatment system. If the system is operating normally and the effluent meets the standards, the current operating mode is maintained. If an abnormality is detected, the operating parameters of the corresponding treatment unit are automatically adjusted, and the intelligent wastewater treatment system is controlled to continue treating the subsequent influent according to the optimized process path.

6. A method for classifying and treating wastewater according to claim 5, characterized in that, The criteria for intelligent graded treatment are as follows: when COD ≤ 150 mg / L, BOD5 ≤ 50 mg / L, ammonia nitrogen ≤ 15 mg / L, total phosphorus ≤ 1.5 mg / L, suspended solids ≤ 80 mg / L, and the heavy metal content is all below the Class I standard of the "Integrated Wastewater Discharge Standard", it is judged as slightly polluted; when COD is between 151 and 400 mg / L, BOD5 is between 51 and 150 mg / L, ammonia nitrogen is between 16 and 45 mg / L, total phosphorus is between 1.6 and 4.0 mg / L, and suspended solids is between 81 and 200 mg / L, or when there is a single heavy metal exceeding the standard but the overall level does not exceed the Class II standard of the "Integrated Wastewater Discharge Standard", it is judged as moderately polluted; when any of the above indicators exceeds the moderate pollution threshold, or when there is a serious exceedance of heavy metals, it is judged as heavily polluted.

7. A method for classifying and treating wastewater according to claim 5, characterized in that, Determining the processing priority includes the following steps: Various pollutants in the influent are detected and analyzed to obtain toxicity coefficients, biodegradation difficulty coefficients, and treatment cost coefficients as comprehensive evaluation factors. A multi-objective optimization model that takes into account treatment effect, treatment time, and operating cost is constructed. Preliminary priorities were set based on pollutant type: heavy metal pollution had the highest priority, followed by nitrogen and phosphorus nutrient pollution, and organic pollution had a relatively lower priority, forming a preliminary ranking framework. By considering the timeliness requirements for treating various pollutants and the energy consumption costs of the treatment process, the time window and energy consumption factors are introduced into the optimization model to provide a basis for dynamic adjustment of priorities. Based on real-time operating conditions and processing objectives, a dynamic weight allocation method is used to adjust the relative weights of the toxicity coefficient, biodegradation difficulty coefficient, and processing cost coefficient, so that the model’s attention to each indicator changes with the operating conditions. By combining a multi-objective optimization model with dynamic weight allocation results, the treatment order of each pollutant is intelligently sorted to generate a final treatment priority list, achieving an optimal balance between treatment effect, treatment time and operating cost.

8. A method for classifying and treating wastewater according to claim 5, characterized in that, The generation of the pretreatment process path includes the following steps: Based on the pollution level and type of pollutants in the influent, the corresponding basic process combination is selected from the preset process path library. Based on the current system load status, the operating efficiency and maintenance status of each processing unit, the basic process combination is dynamically adjusted to form a preprocessing path that conforms to the real-time operating conditions. Considering the impact of seasonal factors and temperature changes on biological treatment efficiency, the process parameters of each treatment unit are compensated and adjusted to maintain treatment stability. Based on historical processing data and intelligent predictive analysis methods, the process path is optimized and predicted to generate a detailed process path that includes the start-up sequence of processing units, dwell time at each stage, and key control parameter settings. Based on the pollution level, corresponding nutrient addition strategies are formulated: for mild pollution, a low nutrient addition mode is adopted, supplementing trace elements and growth factors; for moderate pollution, a balanced nutrient addition mode is adopted, supplementing nutrients at a ratio of C:N:P = 100:5:1; for severe pollution, an enhanced nutrient addition mode is adopted, increasing the nitrogen and phosphorus addition ratio to C:N:P = 100:8:1.5, while adding special enzyme preparations and biocatalysts to improve treatment efficiency.

9. A method for classifying and treating wastewater according to claim 5, characterized in that, The modified carrier is made of polyurethane sponge, and through surface modification treatment, hydrophilic functional groups and nutrient-releasing microspheres are grafted onto its surface, thereby forming a carrier structure with high specific surface area and good hydrophilicity. The carrier density is 20-25 kg / m³. 3 Specific surface area reaches 800-1000 m² 2 / m 3 The porosity is over 95%; The composite flocculant is prepared by mixing polyaluminum chloride, cationic polyacrylamide and natural polymeric flocculant in a mass ratio of 6:2:

1.

10. A method for classifying and treating wastewater according to claim 5, characterized in that, The fuzzy control establishes a control rule base with influent turbidity, pH value, conductivity, and temperature as input variables and flocculant dosage as output variable. It contains 125 control rules. Through the optimization of membership function design and inference rules, it achieves precise control of flocculant dosage, with a dosage accuracy of ±2% and a response time of less than 30 seconds, ensuring the stability and economy of the flocculation process.

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