Hybrid zone variable bioreactor wastewater treatment process

Abstract

The present application relates to sewage treatment technical field, specifically to mixed function area variable type biological reactor sewage treatment process, including the following steps: the sewage to be treated is introduced into the monomer reactor with adjustable aerobic zone, anoxic zone and anaerobic zone; the water quality parameters of influent are detected in real time by online monitoring equipment, and the parameters at least include COD, ammonia nitrogen, total nitrogen and total phosphorus concentration; based on the water quality parameters of influent, the volume ratio of aerobic zone, anoxic zone and anaerobic zone is automatically adjusted by central control system, and the volume ratio adjustment is realized by movable partition; according to the real-time monitored dissolved oxygen, oxidation-reduction potential and pH value in each functional zone, the aeration intensity and internal reflux ratio are adjusted; the nitrification reaction is carried out through the aerobic zone, and ammonia nitrogen is converted into nitrate nitrogen; the denitrification reaction is carried out through the anoxic zone, and nitrate nitrogen is converted into nitrogen; the enhanced biological phosphorus removal is realized through the alternative action of anaerobic zone and aerobic zone; the treated sewage is discharged from the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, and particularly relates to a mixed function zone variable biological reactor sewage treatment process. BACKGROUND

[0002] With the acceleration of urbanization, urban sewage treatment is facing the challenge of large fluctuation of water quality and quantity. The traditional activated sludge process has difficulty in maintaining stable treatment effect when the influent water quality fluctuates greatly, especially for the removal effect of nutrients such as nitrogen and phosphorus, which often needs to increase the treatment unit or increase the dosage to cope with, resulting in increased operating cost and decreased treatment efficiency.

[0003] At present, the mainstream technologies for urban sewage treatment mainly include membrane bioreactor (MBR) technology, A 2 / O process, oxidation ditch process, etc.

[0004] Chinese patent CN203683229U discloses a facultative membrane bioreactor sewage treatment device, which includes a strengthened anaerobic reaction zone and a composite facultative fluidized bed MBR reaction zone. Through the organic combination of strengthened anaerobic hydrolysis and membrane bioreactor, the treatment effect is improved. However, the volume ratio of each functional zone of the device is fixed and cannot be adaptively adjusted according to the change of influent water quality, and the treatment effect is unstable under the condition of large fluctuation of influent water quality.

[0005] Chinese patent CN102249415A discloses a gas-lift type internal circulation denitrification and phosphorus removal biological reactor. By reasonably designing the internal configuration of the gas-lift type internal circulation biological reactor and controlling the aeration intensity, the circulation speed and the dissolved oxygen concentration of the wastewater in the reactor are adjusted, so that the outer peripheral riser is in an aerobic state and the central downcomer is in an anaerobic state. Although this technology can realize simultaneous denitrification and phosphorus removal of wastewater, the volume ratio of the functional zones cannot be flexibly adjusted according to the change of influent water quality.

[0006] US patent US9862628B2 discloses an adjustable bubble size aeration device for membrane bioreactor. By adjusting the inclination angle of the aerator, different sizes of bubbles can be produced at the same time, realizing oxygen transfer and membrane surface cleaning in the sewage treatment process. Although this technology can adjust the aeration effect, it does not involve the adjustment of the volume of the functional zones.

[0007] The article “Simultaneous effective carbon and nitrogen removals and phosphorus recovery in an intermittently aerated membrane bioreactor integrated system” published in the journal Scientific Reports describes an intermittently aerated membrane bioreactor system that achieves simultaneous removal of carbon, nitrogen, and phosphorus by controlling aeration and non-aeration cycles. Although this system achieves functional switching through time dimension control, it lacks the ability to flexibly adjust the proportion of different functional zones in the spatial dimension.

[0008] The article “Simultaneous removal of concentrated organics, nitrogen and phosphorus nutrients by an oxygen-limited membrane bioreactor” published in the journal of Environmental Management describes an oxygen-limited membrane bioreactor that achieves simultaneous removal of organics, nitrogen, and phosphorus by precisely controlling the dissolved oxygen concentration (about 0.2 mg / L). This technology uses a fixed reactor structure and cannot adjust the proportion of different functional zones according to the characteristics of the influent.

[0009] In the above-mentioned prior art, although they all involve nitrogen and phosphorus removal treatment of wastewater, they all have a common shortcoming: they cannot automatically adjust the volume ratio of different functional zones according to changes in the quality of the influent, resulting in unstable treatment effects when facing water quality fluctuations, or the need for a large amount of human intervention to adjust operating parameters, increasing operating costs and operational difficulty. Especially for municipal wastewater treatment with large fluctuations in water quality, existing technologies are difficult to maintain stable nitrogen and phosphorus removal effects and low operating costs at the same time.

[0010] Therefore, there is an urgent need for a biological reactor wastewater treatment process that can automatically adapt to changes in the quality of the influent and flexibly adjust the volume ratio of functional zones to improve treatment efficiency, reduce operating costs, and have high process flexibility. SUMMARY

[0011] In view of the deficiencies of the prior art, the present application provides a mixed functional zone variable biological reactor sewage treatment process, which can automatically adjust the volume ratio of aerobic zone, anoxic zone and anaerobic zone according to the change of influent water quality, accurately adjust the dissolved oxygen and reflux ratio through an intelligent control system, thereby adapting to water quality and quantity fluctuations, maintaining stable nitrogen and phosphorus removal effect, and having the characteristics of low operation cost and high process flexibility, and is particularly suitable for municipal sewage treatment with large water quality fluctuations.

[0012] To achieve the above object, the present application provides a mixed functional zone variable biological reactor sewage treatment process, comprising the following steps:

[0013] The sewage to be treated is introduced into a single reactor with adjustable aerobic zone, anoxic zone and anaerobic zone; the influent water quality parameters are detected in real time by an online monitoring device, and the parameters at least include COD, ammonia nitrogen, total nitrogen and total phosphorus concentration; based on the influent water quality parameters, the volume ratio of the aerobic zone, the anoxic zone and the anaerobic zone is automatically adjusted by a central control system, and the volume ratio adjustment is realized by a movable partition; the aeration intensity and the internal reflux ratio are adjusted according to the real-time monitored dissolved oxygen, oxidation-reduction potential and pH value in each functional zone; the nitrification reaction is carried out in the aerobic zone to convert ammonia nitrogen into nitrate nitrogen; the denitrification reaction is carried out in the anoxic zone to convert nitrate nitrogen into nitrogen gas; the enhanced biological phosphorus removal is realized by the alternative action of the anaerobic zone and the aerobic zone; and the treated sewage is discharged from the system.

[0014] In a preferred embodiment of the present application, the movable partition is adjusted in position by a precision driving system, and the precision driving system comprises: a DC brushless motor with a rated power of 0.25-1.0 kW; a planetary reduction box with a reduction ratio of 50:1 to 100:1; a stainless steel wire rod with a pitch of 5-10 mm; a ceramic-coated aluminum linear guide rail with a bearing capacity of 50-200 kg; the positioning accuracy of the driving system is ±5 mm, and the moving speed is 5-20 mm / min.

[0015] Further, the online monitoring device includes: a dissolved oxygen sensor using optical luminescence method, with a measurement range of 0-20 mg / L and an accuracy of ±0.1 mg / L; an ammonia nitrogen sensor using ion selective electrode, with a measurement range of 0-100 mg / L and an accuracy of ±3%; a nitrate nitrogen sensor using ultraviolet absorption method, with a measurement range of 0-100 mg / L and an accuracy of ±5%; a phosphate sensor using colorimetric method, with a measurement range of 0-20 mg / L and an accuracy of ±2%; a glass electrode pH sensor, with a measurement range of pH 4-10 and an accuracy of ±0.1 unit; a platinum electrode redox potential sensor, with a measurement range of -500 to +500 mV and an accuracy of ±5 mV; and a mixed liquor suspended solids concentration sensor using near-infrared absorption method, with a measurement range of 0-15 g / L and an accuracy of ±5%.

[0016] In another preferred embodiment of the present application, the central control system adopts a multi-level control strategy, including: a basic control loop for maintaining the dissolved oxygen concentration in the aerobic zone at 1.5-3.5 mg / L, the mixing intensity at 5-15 W / m3, and the reflux ratio at 100%-400% of the influent flow rate; a zone volume optimization control for dynamically adjusting the zone volume based on the nitrogen removal requirement, with a response time of 15-60 minutes; and a predictive control for adjusting prediction according to historical performance data and influent mode identification using a machine learning algorithm, with a prediction adjustment time of 1-12 hours; the control system adopts a fuzzy logic controller to adjust the zone volume, and determines the optimal zone configuration based on the influent and effluent water quality parameters.

[0017] Preferably, the aeration system of the aerobic zone includes: a diaphragm type micro-porous aerator made of EPDM, with a bubble size of 1-3 mm; a PVC frame with a maximum pressure bearing of 100 kPa; and an ABS material distribution pipe with a gas flow rate of 2-12 Nm3 / h·m2; the oxygen transfer efficiency of the aeration system under standard conditions (20°C, clean water) is 3.0-4.5 kg O2 / kWh, and the aerator density is 10%-15% of the bottom area.

[0018] Further, the anoxic zone adopts a moderate bubble mixing system, including: an aerator made of HDPE, with a bubble size of 5-8 mm; and a PVC 80 grade distribution pipe, with a gas flow rate of 0.5-2.0 Nm3 / h·m2; the mixing system provides gentle mixing without excessive oxygen transfer, so that the dissolved oxygen level in the anoxic zone is maintained at 0.1-0.5 mg / L.

[0019] In an embodiment of the present application, the anaerobic zone adopts a hydraulic mixing system, which comprises a 316L stainless steel submersible mixer with a motor power of 0.25-1.0 kW, a glass fiber reinforced polypropylene impeller with a diameter of 200-400 mm and a rotating speed of 50-150 rpm, and the mixing system provides a power input of 5-10 W / m3 to prevent the introduction of oxygen and ensure the uniform distribution of biomass.

[0020] In an embodiment of the present application, the process parameters of each functional zone are as follows: aerobic zone: dissolved oxygen 1.5-3.5 mg / L, oxidation-reduction potential +100 to +300 mV, pH 6.8-7.8, hydraulic retention time 4-12 h, mixed liquor suspended solids concentration 3.0-5.0 g / L; anoxic zone: dissolved oxygen 0.1-0.5 mg / L, oxidation-reduction potential -50 to +50 mV, pH 6.8-7.8, hydraulic retention time 2-6 h, mixed liquor suspended solids concentration 3.0-5.0 g / L; anaerobic zone: dissolved oxygen less than 0.1 mg / L, oxidation-reduction potential -100 to -250 mV, pH 6.5-7.5, hydraulic retention time 1-3 h, mixed liquor suspended solids concentration 3.0-5.0 g / L.

[0021] Preferably, the overall system parameters of the process include: total hydraulic retention time 8-24 h; solids retention time 10-30 d; F / M ratio 0.05-0.15 kg BOD / kg MLVSS·d; internal reflux ratio 100%-400% of influent flow rate; reflux activated sludge ratio 50%-100% of influent flow rate; residual sludge discharge rate 3%-10% of system volume per day.

[0022] More preferably, the process further comprises a selected biofilm carrier medium reinforcement system, the biofilm carrier medium is made of HDPE material, has a specific surface area of 500-1000 m2 / m3, a density of 0.95-0.98 g / cm3, a size of 10-25 mm, a filling ratio of 15%-40% of the volume of the zone, and a biofilm thickness of 0.1-2.0 mm; the carrier medium provides an attachment surface for the immobilized professional microbial community, enhances the nitrification in the aerobic zone and the denitrification in the anoxic zone.

[0023] The mixed functional zone variable biological reactor wastewater treatment process provided by the present application has the following beneficial effects:

[0024] (1) Strong self-adaptability: by adjusting the volume ratio of the aerobic zone, the anoxic zone and the anaerobic zone in real time through the movable partition, the treatment process can be automatically adjusted according to the change of the influent water quality, the water quality fluctuation can be adapted, and the stable effluent water quality can be maintained.

[0025] (2) Stable treatment effect: even if the concentrations of COD, ammonia nitrogen, total nitrogen and total phosphorus in the influent fluctuate greatly, the total nitrogen removal rate can still be maintained at 75% to 90%, and the total phosphorus removal rate can still be maintained at 80% to 95%.

[0026] (3) Low energy consumption: by accurately adjusting the aeration intensity, mixing intensity and reflux ratio through the intelligent control system, energy waste is avoided, and the energy consumption per unit of treated water is 0.3-0.8 kilowatt hours / cubic meter, which is 20% to 30% lower than that of the traditional process.

[0027] (4) Simple operation: the full-automatic control system is adopted, manual intervention is reduced, and the operation and maintenance cost and difficulty are reduced.

[0028] (5) Small land occupation: the single reactor realizes variable configuration of multiple functional zones, and the land occupation is reduced by 30% to 50% compared with the traditional multi-pool system.

[0029] (6) Wide adaptability: suitable for municipal wastewater treatment with large water quality and quantity fluctuations, and also suitable for industrial wastewater pretreatment and small-scale decentralized treatment facilities. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structural schematic diagram of the mixed functional zone variable biological reactor of the present application.

[0031] Figure 2 is a movable partition driving system schematic diagram of the mixed functional zone variable biological reactor of the present application.

[0032] Figure 3 is a control system block diagram of the mixed functional zone variable biological reactor of the present application.

[0033] Figure 4 is a flow chart of the wastewater treatment process of the mixed functional zone variable biological reactor of the present application.

[0034] Figure 5 is a total nitrogen removal rate comparison chart of embodiments 1-3 of the present application.

[0035] Figure 6 is a total phosphorus removal rate comparison chart of embodiments 4-6 of the present application.

[0036] Figure 7 is a treatment stability comparison chart of the present application and the comparative example under the condition of fluctuating influent water quality. DETAILED DESCRIPTION

[0037] The present application will be further described in detail below in combination with the drawings and embodiments.

[0038] As Figure 1As shown, the hybrid functional zone variable bioreactor of the present application mainly consists of a reactor body, a movable partition system, an aeration and mixing system, a sensor system and a control system.

[0039] The reactor body is made of glass fiber reinforced plastic (FRP) material, which meets the ASTM D-4097 standard. The reactor wall is made of isophthalic polyester resin (25%-35% by weight) as the matrix, E-glass fiber (60%-70% by weight) as the reinforcing material, vinyl ester resin (3%-7% by weight) as the corrosion-resistant layer, hindered amine light stabilizer (0.5%-1.5% by weight) as the ultraviolet stabilizer, and methyl ethyl ketone peroxide (0.5%-1.5% by weight) as the catalyst. The reactor wall thickness is 8-12 mm, the tensile strength is 100-150 MPa, the flexural modulus is 5-7 GPa, and the chemical stability can be maintained within the pH range of 5.0-9.0 and the temperature range of 5-45℃.

[0040] The movable partition system is the core innovative part of the present application, as shown in Figure 2 The system consists of a partition panel, a sealing system and a drive system. The partition panel is made of polyvinylidene fluoride (PVDF) material, accounting for 70%-80% by weight; the sealing gasket is made of EPDM rubber material, accounting for 5%-10% by weight; the drive shaft is made of 316L stainless steel (UNS S31603) material, accounting for 10%-15% by weight; and the bearing is made of silicon nitride ceramic material, accounting for 2%-5% by weight. The partition moves on a precision track system with a positioning accuracy of ±5 mm, and can adjust the volume of each functional zone to 10%-70% of the total volume of the reactor.

[0041] The present application designs a special aeration and mixing system according to the needs of different functional zones.

[0042] The aerobic zone adopts a fine bubble aeration system, including a membrane type micro-bubble aerator made of EPDM material, which produces 1-3 mm bubbles; a PVC frame with a maximum pressure of 100 kPa; and an ABS distribution pipe with a gas flow range of 2-12 standard cubic meters / hour·square meter. Under standard conditions (20℃, clean water), the oxygen transfer efficiency of this aeration system is 3.0-4.5 kg oxygen / kWh, and the aerator density is about 10%-15% of the area at the bottom of the reactor.

[0043] The anoxic zone adopts a moderate bubble mixing system, including an aerator made of HDPE material, which produces 5-8 mm bubbles; and a PVC 80 distribution pipe with a gas flow of 0.5-2.0 standard cubic meters / hour·square meter. The design purpose of this system is to provide sufficient mixing intensity while maintaining a low oxygen transfer rate, so that the dissolved oxygen concentration in the anoxic zone is maintained within the ideal range of 0.1-0.5 mg / L.

[0044] The anaerobic zone employs a hydraulic mixing system, including a 316L stainless steel submersible mixer with a motor power of 0.25-1.0 kW; a glass fiber reinforced polypropylene impeller with a diameter of 200-400 mm; and an operating speed of 50-150 rpm. This mixing system provides a power input of 5-10 W / m³, ensuring uniform biomass distribution while preventing the introduction of oxygen into the anaerobic environment.

[0045] like Figure 3 As shown, this invention employs a comprehensive online monitoring sensor network, including: a dissolved oxygen sensor using optical emission (measurement range 0-20 mg / L, accuracy ±0.1 mg / L); an ammonia nitrogen sensor using an ion-selective electrode (measurement range 0-100 mg / L, accuracy ±3%); a nitrate nitrogen sensor using ultraviolet absorption (measurement range 0-100 mg / L, accuracy ±5%); a phosphate sensor using colorimetry (measurement range 0-20 mg / L, accuracy ±2%); a glass electrode pH sensor (measurement range pH 4-10, accuracy ±0.1 units); a platinum electrode redox potential sensor (measurement range -500 to +500 mV, accuracy ±5 mV); and a mixed liquor suspended solids concentration sensor using near-infrared absorption (measurement range 0-15 g / L, accuracy ±5%). All sensors are certified for continuous operation in wastewater environments, equipped with a self-cleaning mechanism, and have a calibration interval of 7–30 days.

[0046] The control system hardware includes an industrial-grade programmable logic controller (PLC) with a scan time of 10-20 milliseconds; a touch screen human-machine interface (HMI) with a 10-15 inch display, IP65 protection rating, and NEMA 4X protective enclosure; an industrial Ethernet and Modbus TCP / IP communication network with a communication speed of 10 / 100 megabits per second; and a 24V DC uninterruptible power supply system with a backup time of 1-4 hours.

[0047] The control system adopts a three-level hierarchical control strategy: the first level is the basic control loop, which maintains the dissolved oxygen concentration in the aerobic zone at 1.5-3.5 mg / L, the mixing intensity at 5-15 W / m³, and the reflux ratio at 100%-400% of the influent flow rate; the second level is zone volume optimization control, which dynamically adjusts the zone volume based on nitrogen removal requirements, with a response time of 15-60 minutes; the third level is predictive control, which uses machine learning algorithms to make adjustments and predictions based on historical performance data and influent pattern recognition, with a prediction and adjustment time of 1-12 hours.

[0048] The regional volume adjustment is based on a fuzzy logic controller, the input variables include the ammonia nitrogen concentration of the influent (divided into low, medium and high levels, corresponding to 0-20, 15-40 and >35 mg / L respectively), the phosphate concentration of the influent (divided into low, medium and high levels, corresponding to 0-3, 2-6 and >5 mg / L respectively), the ammonia nitrogen concentration of the effluent, the nitrate concentration of the effluent and the phosphate concentration of the effluent; the output variable is the percentage of the volume of each functional area (the aerobic area is 20%-70%, the anoxic area is 20%-60% and the anaerobic area is 10%-40%). For example, if the ammonia nitrogen concentration of the influent is high and the ammonia nitrogen concentration of the effluent is medium or high, the volume of the aerobic area is increased; if the nitrate concentration of the effluent is high and the COD concentration of the influent is medium or high, the volume of the anoxic area is increased; if the phosphate concentration of the influent is high and the phosphate concentration of the effluent is medium or high, the volume of the anaerobic area is increased.

[0049] The sewage treatment process of the present application is based on the mature biological denitrification and dephosphorization mechanism, and the treatment effect is optimized through variable regional configuration.

[0050] The nitrogen conversion process mainly includes nitrification in the aerobic area and denitrification in the anoxic area. In the aerobic area, ammonia nitrogen is oxidized to nitrite under the action of ammonia-oxidizing bacteria (such as Nitrosomonas), and then further oxidized to nitrate under the action of nitrite-oxidizing bacteria (such as Nitrobacter and Nitrosospira). The reaction formula of this process is: NH4 + + 1.5O2→ NO2 - + 2H + + H2O and NO2 - + 0.5O2→ NO3 - The rate of the nitrification process is affected by the dissolved oxygen (>1.5 mg / L), temperature (optimum 25-30℃) and pH value (optimum 7.2-8.0).

[0051] In the anoxic area, nitrate is reduced to nitrogen gas under the action of denitrifying bacteria (such as Pseudomonas, Paracoccus and Yeehesia) with organic carbon source as the electron donor. The reaction formula can be expressed as: NO3 - + 1.08CH3OH + 0.24H2CO3→ 0.056C5H7NO2 + 0.47N2 + 1.68H2O + HCO3 - The rate of the denitrification process is mainly affected by the availability of carbon source (COD / N ratio is 4-6), temperature and dissolved oxygen concentration.

[0052] Phosphorus removal is mainly achieved by the metabolic activities of polyphosphate-accumulating organisms (PAOs) under alternating anaerobic-aerobic conditions. Under anaerobic conditions, PAOs release phosphate while taking up volatile fatty acids (VFAs) and storing them as polyhydroxyalkanoates (PHAs), with the energy coming from the hydrolysis of polyphosphate. Under subsequent aerobic conditions, PAOs oxidize stored PHAs to gain energy, take up phosphate and store it as polyphosphate. Net phosphorus removal is achieved by the discharge of phosphorus-rich sludge.

[0053] The innovation of the present application is that by adjusting the volume proportion of each functional zone in real time, the above-mentioned biological reaction process is optimized, so that the system can automatically adjust the most suitable treatment configuration according to the characteristics of the influent, thereby maximizing the energy utilization efficiency while ensuring the effluent quality.

[0054] The present application will be further described below through specific examples, but these examples should not be regarded as limiting the present application.

[0055] Example 1: Treatment of medium-strength municipal wastewater

[0056] In this example, a mixed functional zone variable biological reactor with a working volume of 100 cubic meters is used to treat medium-strength municipal wastewater. The reactor body is made of glass fiber reinforced plastic, with a wall thickness of 10 millimeters, a tensile strength of 125 megapascals, and a bending modulus of 6 gigapascals. The movable partition system uses PVDF material partitions (75% by weight), EPDM rubber sealing rings (7.5% by weight), 316L stainless steel drive shafts (12.5% by weight), and silicon nitride ceramic bearings (5% by weight). The drive system uses a 0.5-kilowatt direct-current brushless motor, with a planetary reduction gearbox having a reduction ratio of 75:1, a stainless steel wire rod pitch of 7.5 millimeters, and a ceramic-coated aluminum linear guide bearing capacity of 100 kilograms.

[0057] The treated influent water quality parameters are: COD 300-400 milligrams / liter, BOD 150-200 milligrams / liter, NH4 + -N 30-40 milligrams / liter, TP 4-6 milligrams / liter, and water temperature 15-25°C.

[0058] The initial setting of the functional zone volume proportion of the system is: aerobic zone 40%, anoxic zone 35%, and anaerobic zone 25%. As the system runs, the control system automatically adjusts the volume proportion of each zone according to the real-time monitoring of water quality parameters, generally maintaining the aerobic zone at 35%-45%, the anoxic zone at 30%-40%, and the anaerobic zone at 20%-30%.

[0059] The online monitoring system is configured to include a dissolved oxygen sensor (measuring range 0-20 mg / L, accuracy ±0.1 mg / L), an ammonia nitrogen sensor (measuring range 0-100 mg / L, accuracy ±3%), a nitrate nitrogen sensor (measuring range 0-100 mg / L, accuracy ±5%), a phosphate sensor (measuring range 0-20 mg / L, accuracy ±2%), a pH sensor (measuring range pH 4-10, accuracy ±0.1 unit), an ORP sensor (measuring range -500 to +500 mV, accuracy ±5 mV), and an MLSS sensor (measuring range 0-15 g / L, accuracy ±5%).

[0060] The aerobic zone uses a membrane type micro-aeration device made of EPDM material, with bubble size of 1-3 mm, a PVC frame with maximum pressure bearing of 100 kPa, and an ABS material distribution pipe, with a gas flow of 8 standard cubic meters / hour·square meter. The anoxic zone uses an aeration device made of HDPE material, with bubble size of 5-8 mm, a PVC 80 grade distribution pipe, and a gas flow of 1.0 standard cubic meters / hour·square meter. The anaerobic zone uses a 316L stainless steel submersible mixer, with motor power of 0.5 kW, a glass fiber reinforced polypropylene impeller with diameter of 300 mm, and a rotating speed of 100 revolutions / minute.

[0061] The operating parameters are set as follows: in the aerobic zone, the dissolved oxygen is 2.5 mg / L, the oxidation-reduction potential is +200 mV, the pH value is 7.3, the hydraulic retention time is 8 hours, and the MLSS concentration is 4.0 g / L; in the anoxic zone, the dissolved oxygen is 0.3 mg / L, the oxidation-reduction potential is 0 mV, the pH value is 7.3, the hydraulic retention time is 4 hours, and the MLSS concentration is 4.0 g / L; in the anaerobic zone, the dissolved oxygen is <0.1 mg / L, the oxidation-reduction potential is -175 mV, the pH value is 7.0, the hydraulic retention time is 2 hours, and the MLSS concentration is 4.0 g / L.

[0062] The total hydraulic retention time of the system is 14 hours, the solid retention time is 20 days, the F / M ratio is 0.1 kg BOD / kg MLVSS·day, the internal reflux ratio is 200% of the influent flow, the reflux activated sludge ratio is 75% of the influent flow, and the residual sludge discharge rate is 5% of the system volume per day.

[0063] After 30 days of operation, the system reaches a stable state, and the effluent water quality indicators are as follows: COD 35 mg / L, BOD 8 mg / L, NH4 + -N 0.8 mg / L, TN 8 mg / L, and TP 0.5 mg / L. The wastewater treatment efficiency is as follows: COD removal rate 91%, BOD removal rate 96%, TN removal rate 85%, and TP removal rate 90%. The system energy consumption is 0.5 kWh / m3.

[0064] Example 2: Treatment of high-nitrogen and low-carbon wastewater

[0065] This embodiment uses a mixed function zone variable bioreactor with a working volume of 50 cubic meters to treat industrial mixed sewage with high nitrogen and low carbon ratio. The reactor structure and material are the same as in Example 1, but the size is correspondingly reduced.

[0066] The water quality parameters of the treated influent are: COD 200-250 mg / L, BOD 80-120 mg / L, NH4 + -N 50-60 mg / L, TP 3-4 mg / L, water temperature 20-30°C. The influent C / N ratio is low, about 4:1.

[0067] The initial setting of the system is that the volume ratio of the functional zones is: aerobic zone 50%, anoxic zone 40%, anaerobic zone 10%. As the system operates, the control system automatically adjusts the volume ratio of each zone according to the real-time monitoring of water quality parameters, generally maintaining the aerobic zone at 45%-55%, the anoxic zone at 35%-45%, and the anaerobic zone at 5%-15%.

[0068] In this embodiment, in order to enhance the nitrogen removal effect under low C / N ratio conditions, biological membrane carrier medium is added in the anoxic zone. The material is HDPE, the specific surface area is 800 square meters per cubic meter, the density is 0.96 grams per cubic centimeter, and the size is 15 millimeters, with a filling ratio of 30% of the zone volume.

[0069] The aeration system in the aerobic zone uses membrane type micro-porous aerators made of EPDM material, with bubble size of 1-3 mm and gas flow rate of 10 standard cubic meters per hour per square meter. The mixing system in the anoxic zone uses aerators made of HDPE material, with bubble size of 6-8 mm and gas flow rate of 0.8 standard cubic meters per hour per square meter. The anaerobic zone uses a 316L stainless steel submersible mixer with motor power of 0.4 kW, glass fiber reinforced polypropylene impeller diameter of 250 mm, and rotation speed of 120 rpm.

[0070] The operating parameters are set as follows: in the aerobic zone, dissolved oxygen 3.0 mg / L, oxidation-reduction potential +250 mV, pH 7.5, hydraulic retention time 9 hours, MLSS concentration 4.5 g / L; in the anoxic zone, dissolved oxygen 0.2 mg / L, oxidation-reduction potential -25 mV, pH 7.4, hydraulic retention time 5 hours, MLSS concentration 4.5 g / L; in the anaerobic zone, dissolved oxygen <0.1 mg / L, oxidation-reduction potential -200 mV, pH 7.0, hydraulic retention time 1 hour, MLSS concentration 4.5 g / L.

[0071] The total hydraulic retention time of the system is 15 hours, the solid retention time is 25 days, the internal reflux ratio is 300% of the influent flow rate, the reflux activated sludge ratio is 80% of the influent flow rate, and the residual sludge discharge rate is 4% of the system volume per day.

[0072] After 30 days of operation, the system reached a steady state, and the effluent water quality indicators were: COD 30 mg / L, BOD 6 mg / L, NH4 + - N 1.0 mg / L, TN 10 mg / L, TP 0.6 mg / L. The wastewater treatment efficiency was: COD removal rate 88%, BOD removal rate 95%, TN removal rate 82%, TP removal rate 85%. The system energy consumption was 0.6 kWh / m3.

[0073] Example 3: Treatment of high-phosphorus industrial wastewater

[0074] This example used a mixed-function zone variable bioreactor with a working volume of 200 m3to treat high-phosphorus food processing industrial wastewater. The reactor was constructed and made of the same materials as in Example 1, but the size was correspondingly enlarged.

[0075] The water quality parameters of the treated influent were: COD 500-600 mg / L, BOD 300-350 mg / L, NH4 + - N 30-40 mg / L, TP 10-15 mg / L, water temperature 15-25°C.

[0076] The initial setting of the system functional zone volume ratio was: aerobic zone 35%, anoxic zone 25%, anaerobic zone 40%. As the system operated, the control system automatically adjusted the volume ratio of each zone according to real-time monitoring of water quality parameters, generally maintaining an aerobic zone of 30%-40%, an anoxic zone of 20%-30%, and an anaerobic zone of 35%-45%.

[0077] In this example, to enhance biological phosphorus removal, a prolonged anaerobic zone hydraulic retention time and enhanced aerobic-anaerobic alternating cycles were used. The aerobic zone aeration system used EPDM membrane type micro-porous aerators, with bubble sizes of 1-2 mm and a gas flow rate of 12 Nm3 / h / m2. The anoxic zone mixing system used HDPE aeration devices, with bubble sizes of 5-6 mm and a gas flow rate of 1.5 Nm3 / h / m2. The anaerobic zone used a 316L stainless steel submersible mixer, with a motor power of 0.75 kW, a glass fiber reinforced polypropylene impeller diameter of 350 mm, and a rotational speed of 80 rpm.

[0078] The operating parameters were set as follows: aerobic zone dissolved oxygen 3.5 mg / L, oxidation-reduction potential +300 mV, pH value 7.6, hydraulic retention time 6 hours, MLSS concentration 5.0 g / L; anoxic zone dissolved oxygen 0.2 mg / L, oxidation-reduction potential -25 mV, pH value 7.4, hydraulic retention time 3 hours, MLSS concentration 5.0 g / L; anaerobic zone dissolved oxygen <0.1 mg / L, oxidation-reduction potential -230 mV, pH value 6.8, hydraulic retention time 3 hours, MLSS concentration 5.0 g / L.

[0079] The total hydraulic retention time of the system is 12 hours, the solid retention time is 15 days, the internal reflux ratio is 350% of the influent flow, the reflux activated sludge ratio is 90% of the influent flow, and the residual sludge discharge rate is 7% of the system volume per day.

[0080] After 30 days of operation, the system reaches a steady state, and the effluent water quality indicators are: COD 40 mg / L, BOD 10 mg / L, NH4 + -N 1.5 mg / L, TN 12 mg / L, TP 0.6 mg / L. The wastewater treatment efficiency is: COD removal rate 93%, BOD removal rate 97%, TN removal rate 68%, and TP removal rate 95%. The system energy consumption is 0.7 kWh / m3.

[0081] Example 4: Treatment of municipal wastewater in low temperature season

[0082] This example uses a mixed function zone variable bioreactor with a working volume of 150 cubic meters to treat municipal wastewater under low temperature conditions in winter. The reactor structure and material are the same as in Example 1, but an insulation layer is added to the outer wall of the reactor.

[0083] The water quality parameters of the influent treated are: COD 250-350 mg / L, BOD 120-180 mg / L, NH4 + -N 25-35 mg / L, TP 3-5 mg / L, water temperature 5-10°C.

[0084] The initial setting of the functional zone volume ratio of the system is: aerobic zone 55%, anoxic zone 30%, anaerobic zone 15%. As the system operates, the control system automatically adjusts the volume ratio of each zone according to real-time monitoring of water quality parameters, generally maintaining an aerobic zone of 50%-60%, an anoxic zone of 25%-35%, and an anaerobic zone of 10%-20%.

[0085] In this example, to address the problem of reduced biological activity under low temperature conditions, the proportion of the aerobic zone is increased, and biological membrane carrier media are added to both the aerobic and anoxic zones. The HDPE material has a specific surface area of 1000 m2 / m3, a density of 0.97 g / cm3, and a size of 20 mm, with a filling ratio of 40% and 30% of the zone volume, respectively.

[0086] The aeration system in the aerobic zone uses EPDM material membrane type micro-bubble aerator, with bubble size of 1-2 mm and gas flow of 10 standard cubic meters / hour*m2. The mixing system in the anoxic zone uses HDPE material aerator, with bubble size of 5-6 mm and gas flow of 1.2 standard cubic meters / hour*m2. The anaerobic zone uses 316L stainless steel submersible agitator, with motor power of 0.6 kW, glass fiber reinforced polypropylene impeller diameter of 300 mm and rotation speed of 100 r / min.

[0087] The operation parameters are set as follows: dissolved oxygen in the aerobic zone of 3.0 mg / L, oxidation-reduction potential of +250 mV, pH value of 7.2, hydraulic retention time of 12 hours and MLSS concentration of 4.0 g / L; dissolved oxygen in the anoxic zone of 0.3 mg / L, oxidation-reduction potential of -30 mV, pH value of 7.2, hydraulic retention time of 6 hours and MLSS concentration of 4.0 g / L; dissolved oxygen in the anaerobic zone of <0.1 mg / L, oxidation-reduction potential of -150 mV, pH value of 7.0, hydraulic retention time of 2 hours and MLSS concentration of 4.0 g / L.

[0088] The total hydraulic retention time of the system is 20 hours, the solid retention time is 28 days, the internal reflux ratio is 250% of the influent flow, the reflux activated sludge ratio is 70% of the influent flow, and the residual sludge discharge rate is 3.5% of the system volume per day.

[0089] After 45 days of operation, the system reaches a stable state, and the effluent quality indexes are as follows: COD 45 mg / L, BOD 12 mg / L, NH4 + -N 2.0 mg / L, TN 15 mg / L and TP 0.8 mg / L. The wastewater treatment efficiency is as follows: COD removal rate 85%, BOD removal rate 93%, TN removal rate 57% and TP removal rate 80%. The system energy consumption is 0.8 kWh / m3.

[0090] Example 5: Treatment of high hydraulic load municipal wastewater

[0091] This example uses a mixed function zone variable bioreactor with a working volume of 300 m3 to treat municipal wastewater under high hydraulic load conditions in the rainy season. The reactor structure and material are the same as in Example 1, but the size is enlarged accordingly.

[0092] The treated influent water quality parameters are as follows: COD 150-200 mg / L, BOD 70-100 mg / L, NH4 + -N 15-20 mg / L, TP 2-3 mg / L, water temperature 20-25°C, and hydraulic load 50% higher than the conventional design.

[0093] The initial setting function area volume ratio of the system is: aerobic zone 45%, anoxic zone 35%, anaerobic zone 20%. With the system running, the control system automatically adjusts the volume ratio of each zone according to the real-time monitoring of water quality parameters, generally maintaining between 40% to 50% of the aerobic zone, 30% to 40% of the anoxic zone, and 15% to 25% of the anaerobic zone.

[0094] To cope with high hydraulic load conditions, this embodiment uses a high-density aeration system in the aerobic zone, with a density of up to 15% of the bottom area, and increases the mixing intensity in the anoxic and anaerobic zones. The aerobic zone aeration system uses EPDM membrane micro-porous aerators, with bubble sizes of 1 to 2 mm and a gas flow rate of 12 standard cubic meters per hour per square meter. The anoxic zone mixing system uses HDPE aerators, with bubble sizes of 6 to 8 mm and a gas flow rate of 1.8 standard cubic meters per hour per square meter. The anaerobic zone uses a 316L stainless steel submersible mixer, with a motor power of 1.0 kW and a glass fiber reinforced polypropylene impeller diameter of 400 mm, rotating at 120 rpm.

[0095] The operating parameters are set as follows: dissolved oxygen in the aerobic zone is 2.0 mg / L, oxidation-reduction potential is +180 mV, pH value is 7.4, hydraulic retention time is 5 hours, and MLSS concentration is 4.5 g / L; dissolved oxygen in the anoxic zone is 0.3 mg / L, oxidation-reduction potential is -20 mV, pH value is 7.3, hydraulic retention time is 3 hours, and MLSS concentration is 4.5 g / L; dissolved oxygen in the anaerobic zone is <0.1 mg / L, oxidation-reduction potential is -180 mV, pH value is 7.0, hydraulic retention time is 1.5 hours, and MLSS concentration is 4.5 g / L.

[0096] The total hydraulic retention time of the system is 9.5 hours, the solid retention time is 12 days, the internal reflux ratio is 300% of the influent flow, the reflux activated sludge ratio is 85% of the influent flow, and the residual sludge discharge rate is 8% of the system volume per day.

[0097] After 30 days of operation, the system reaches a stable state, with the following effluent water quality indicators: COD 40 mg / L, BOD 10 mg / L, NH4 + -N 1.5 mg / L, TN 10 mg / L, TP 0.7 mg / L. The wastewater treatment efficiency is: COD removal rate 78%, BOD removal rate 89%, TN removal rate 77%, and TP removal rate 75%. The system energy consumption is 0.65 kWh / m3.

[0098] Example 6: Treatment of mixed wastewater with large water quality fluctuations

[0099] This embodiment uses a mixed function area variable bioreactor with a working volume of 120 cubic meters to treat urban and industrial mixed wastewater with large water quality fluctuations. The reactor structure and materials are the same as in Example 1.

[0100] The fluctuation range of the water quality parameters of the influent is large: COD 200-700 mg / L, BOD 100-400 mg / L, NH4 + N 20-70 mg / L, TP 3-12 mg / L, and water temperature 15-30°C.

[0101] The embodiment fully plays the advantages of the variable function zone, and the control system dynamically adjusts the volume proportion of each zone according to the real-time monitoring of the influent water quality. The aerobic zone is in the range of 20% to 60%, the anoxic zone is in the range of 20% to 50%, and the anaerobic zone is in the range of 10% to 40%.

[0102] In order to enhance the adaptability of the system, the biological membrane carrier medium is added to the three function zones. The material is HDPE, the specific surface area is 800 square meters per cubic meter, the density is 0.96 grams per cubic centimeter, and the size is 15 millimeters. The filling proportion is 35%, 25%, and 20% of the volume of the region, respectively.

[0103] The aeration system of the aerobic zone adopts a membrane type micro-porous aerator with an EPDM material, the bubble size is 1-3 millimeters, and the gas flow is 2-12 standard cubic meters per hour per square meter, which is automatically adjusted by the control system according to the dissolved oxygen demand. The mixing system of the anoxic zone adopts an aerator with an HDPE material, the bubble size is 5-8 millimeters, and the gas flow is 0.5-2.0 standard cubic meters per hour per square meter. The anaerobic zone adopts a 316L stainless steel submersible mixer, the motor power is 0.5 kilowatts, the glass fiber reinforced polypropylene impeller diameter is 300 millimeters, and the rotating speed is 50-150 revolutions per minute, which is automatically adjusted by the control system according to the mixing demand.

[0104] The operating parameter settings are as follows: the dissolved oxygen of the aerobic zone is 1.5-3.5 mg / L, the oxidation-reduction potential is +100 to +300 millivolts, the pH value is 6.8-7.8, the hydraulic retention time is 4-12 hours, and the MLSS concentration is 3.0-5.0 g / L; the dissolved oxygen of the anoxic zone is 0.1-0.5 mg / L, the oxidation-reduction potential is -50 to +50 millivolts, the pH value is 6.8-7.8, the hydraulic retention time is 2-6 hours, and the MLSS concentration is 3.0-5.0 g / L; the dissolved oxygen of the anaerobic zone is <0.1 mg / L, the oxidation-reduction potential is -100 to -250 millivolts, the pH value is 6.5-7.5, the hydraulic retention time is 1-3 hours, and the MLSS concentration is 3.0-5.0 g / L.

[0105] The total hydraulic retention time of the system is 8-24 hours, the solid retention time is 10-30 days, the internal reflux ratio is 100%-400% of the influent flow, the reflux activated sludge ratio is 50%-100% of the influent flow, and the residual sludge discharge rate is 3%-10% of the system volume per day.

[0106] After 60 days of operation, despite significant fluctuations in influent water quality, the system maintained stable treatment performance, with average effluent water quality indicators of: COD 45 mg / L, BOD 12 mg / L, and NH4+. + -N 1.8 mg / L, TN 12 mg / L, TP 0.9 mg / L. Wastewater treatment efficiency: COD removal rate 88%, BOD removal rate 94%, TN removal rate 80%, TP removal rate 85%. The average energy consumption of the system is 0.55 kWh / m³.

[0107] To verify the innovativeness and superiority of this invention, the following comparative examples were designed:

[0108] Comparative Example 1: Traditional A with a fixed area proportion 2 / O process

[0109] This comparative example uses A of the same volume as in Example 1. 2 The system uses an O process, but the volume ratio of each functional zone is fixed: 15% for the anaerobic zone, 25% for the anoxic zone, and 60% for the aerobic zone. The remaining equipment and materials are basically the same as in Example 1, but it does not have the function of automatically adjusting the volume ratio of the functional zones.

[0110] Under the same influent conditions (COD 300-400 mg / L, BOD 150-200 mg / L, NH4+), + With ammonia nitrogen concentrations of 30-40 mg / L and TP concentrations of 4-6 mg / L, and a water temperature of 15-25°C, the system's treatment effect was comparable to that of Example 1 when the influent water quality was stable. However, when the influent water quality fluctuated, especially when the ammonia nitrogen concentration increased to 50 mg / L, the effluent ammonia nitrogen concentration increased to 4.5 mg / L, and the total nitrogen removal rate decreased to 70%, because the aerobic zone volume ratio could not be increased. Simultaneously, the system energy consumption increased to 0.65 kWh / m³, approximately 30% higher than that of Example 1.

[0111] Comparative Example 2: Variable Zone Bioreactor without Intelligent Control System

[0112] This comparative example uses the same movable partition system as Example 6, but it is not equipped with an intelligent control system. The volume adjustment of the functional areas needs to be done manually based on the laboratory water quality analysis results. The adjustment frequency is limited to once a day, and the adjustment decision depends on the operator's experience.

[0113] Treating the same mixed wastewater with large fluctuations in water quality (COD 200-700 mg / L, BOD 100-400 mg / L, NH4+) +- N 20-70 mg / L, TP 3-12 mg / L, water temperature 15-30°C), the average treatment effect of the system during 60 days of operation was: COD removal rate 82%, BOD removal rate 90%, TN removal rate 72%, TP removal rate 78%. The average value of the effluent water quality indicators was: COD 65 mg / L, BOD 20 mg / L, NH4 + - N 4.5 mg / L, TN 18 mg / L, TP 1.6 mg / L. The average energy consumption of the system was 0.7 kWh / m3.

[0114] Compared with Example 6, Comparative Example 2 performed poorly in both treatment efficiency and energy consumption, the main reason being that manual adjustment could not respond to water quality changes in time, and the accuracy of adjustment decisions was limited by the experience of the operator.

[0115] Comparative Example 3: Membrane bioreactor (MBR) system

[0116] This comparative example used a conventional membrane bioreactor system, with the same working volume as Example 1, but used a fixed functional zone design to improve biomass concentration and effluent water quality through a membrane separation device.

[0117] Under the same influent conditions (COD 300-400 mg / L, BOD 150-200 mg / L, NH4 + - N 30-40 mg / L, TP 4-6 mg / L, water temperature 15-25°C), the effluent water quality indicators of the system were: COD 25 mg / L, BOD 5 mg / L, NH4 + - N 0.5 mg / L, TN 9 mg / L, TP 0.8 mg / L. Sewage treatment efficiency: COD removal rate 93%, BOD removal rate 97%, TN removal rate 80%, TP removal rate 85%.

[0118] Although the effluent water quality of the MBR system was slightly better than that of Example 1, its energy consumption was as high as 1.2 kWh / m3, which was 2.4 times that of Example 1. At the same time, the initial investment cost of the MBR system was about 40% higher than that of Example 1, the membrane components needed to be replaced regularly, and the operation and maintenance cost was higher.

[0119] Comparative Example 4: Low-temperature running system without biological membrane carrier

[0120] This comparative example had the same configuration as Example 4, but did not add biological membrane carrier medium. After running for 45 days under low-temperature conditions (water temperature 5-10°C), the treatment effect of the system was: COD removal rate 75%, BOD removal rate 85%, TN removal rate 45%, TP removal rate 70%. The effluent water quality indicators were: COD 70 mg / L, BOD 22 mg / L, NH4 +- N 8.0 mg / L, TN 20 mg / L, TP 1.2 mg / L.

[0121] Compared with Example 4 with biofilm carrier added, the treatment effect is obviously reduced, especially the removal efficiency of ammonia nitrogen, which shows that the biofilm carrier plays an important role in maintaining the activity of nitrifying bacteria under low temperature conditions.

[0122] To comprehensively evaluate the performance of the mixed function zone variable biological reactor wastewater treatment process of the present application, systematic performance tests were conducted on the above examples and comparative examples. The test methods and indexes are as follows:

[0123] The concentrations of ammonia nitrogen, nitrate nitrogen, nitrite nitrogen and total nitrogen in the influent and effluent were determined by using standard water quality analysis methods. The total nitrogen removal rate was calculated according to the following formula: TN removal rate (%) = 100 x (TN influent - TN effluent) / TN influent. The ammonia nitrogen removal rate was calculated according to the following formula: NH4 + - N removal rate (%) = 100 x (NH4 + - N influent - NH4 + - N effluent) / NH4 + - N influent.

[0124] Figure 5 The total nitrogen removal rates of Examples 1-3 and Comparative Examples 1 and 2 under the condition of fluctuation of influent water quality are shown. The results show that the variable function zone biological reactor of the present application can maintain a relatively high and stable total nitrogen removal rate (75%-85%) under the condition of fluctuation of influent ammonia nitrogen concentration, while the total nitrogen removal rate of Comparative Example 1 with fixed zone ratio obviously decreases to below 70% when the influent ammonia nitrogen concentration increases. Although Comparative Example 2 has the function of adjustable zone, its total nitrogen removal rate fluctuates greatly (65%-80%) due to untimely adjustment.

[0125] The concentrations of orthophosphate and total phosphorus in the influent and effluent were determined by using standard water quality analysis methods. The total phosphorus removal rate was calculated according to the following formula: TP removal rate (%) = 100 x (TP influent - TP effluent) / TP influent.

[0126] Figure 6 The total phosphorus removal rates of Examples 4-6 and Comparative Examples 3 and 4 under the condition of fluctuation of influent total phosphorus concentration are shown. The results show that the system of the present application can maintain a total phosphorus removal rate of 80%-95% by automatically adjusting the volume ratio of anaerobic zone when the influent total phosphorus concentration changes. Although the MBR system (Comparative Example 3) has a relatively high solid retention capacity, its phosphorus removal efficiency decreases to about 75% when the influent total phosphorus concentration significantly increases. The phosphorus removal rate of Comparative Example 4 further decreases to 70% under low temperature conditions due to the lack of support of biofilm carrier.

[0127] To test the stability of the system under the condition of large fluctuation of influent quality, a 60-day continuous operation test was conducted on Example 6 and Comparative Example 2, during which multiple influent quality shock loads were artificially created.

[0128] Figure 7 The changes of effluent quality of the two systems when facing a 50% sudden increase in the concentrations of COD, ammonia nitrogen and total phosphorus in the influent are shown. The results show that the intelligent control system of the application can quickly respond to changes in influent quality, automatically adjust the volume ratio of functional zones and operating parameters, and make the effluent quality recover to stability within 12 hours after the shock load. Comparative Example 2, which lacks intelligent control, takes more than 48 hours to recover to stable effluent quality, and the fluctuation range is larger.

[0129] The energy consumption of each system was monitored, including aeration energy consumption, stirring energy consumption, pumping energy consumption and control system energy consumption. The results show that the average energy consumption of Example is 0.5-0.8 kilowatt-hours per cubic meter, which is 20%-30% less than that of the traditional A2 / O process (Comparative Example 1) and 40%-60% less than that of the MBR system (Comparative Example 3).

[0130] The main sources of energy saving are: (1) by precisely controlling the volume ratio of functional zones, optimizing the biological treatment process and reducing unnecessary energy consumption; (2) using fine aeration control, adjusting the aeration amount according to the actual oxygen demand; (3) dynamically adjusting the internal reflux ratio according to the treatment demand to avoid excessive pumping.

[0131] Through comprehensive evaluation of the treatment effect, energy efficiency and adaptability of each example, Example 6 shows the best comprehensive performance, especially suitable for mixed sewage treatment with large water quality fluctuations. This example fully embodies the advantages of the core innovation of the application - self-adaptive functional zone volume adjustment and intelligent control system, which ensures the effluent quality while achieving lower energy consumption and higher system stability.

[0132] The core working mechanism of the mixed functional zone variable biological reactor wastewater treatment process of the application is that:

[0133] (1) Dynamic spatial allocation: through the movable partition system, the volume ratio of aerobic zone, anoxic zone and anaerobic zone is adjusted in real time, so that the spatial resources of the reactor can be optimally allocated according to the treatment demand. For example, when the ammonia nitrogen load of the influent increases, the system will automatically increase the volume ratio of the aerobic zone to improve the nitrification capacity; when the total phosphorus concentration of the influent increases, the system will increase the volume ratio of the anaerobic zone to strengthen the biological phosphorus removal effect.

[0134] (2) Precise environmental control: Through multi-point online monitoring system and multi-level control strategy, the ideal environmental parameters of each functional area, such as dissolved oxygen, oxidation-reduction potential and pH value, are accurately maintained, creating the most suitable conditions for the growth and metabolic activity of specific microbial communities. This precise control enables simultaneous and efficient nitrification, denitrification and biological phosphorus removal.

[0135] (3) Predictive adjustment: Based on the predictive control function of machine learning algorithm, the system can predict the trend of influent water quality change according to historical data and influent mode recognition, and adjust the system configuration in advance to avoid the fluctuation of treatment effect caused by lag response.

[0136] (4) Multi-level biological enhancement: Through the optional biofilm carrier system, the system increases the specific functional microorganisms attached to the fixed biomass, improving the biological treatment capacity of the system, especially under low temperature or high load conditions, effectively making up for the problem of insufficient planktonic activity.

[0137] The synergistic effect of these mechanisms enables the present application to effectively adapt to the fluctuation of influent water quality while maintaining high treatment efficiency, achieving intelligent, efficient and low energy consumption of wastewater treatment.

[0138] The mixed functional zone variable biological reactor wastewater treatment process provided by the present application realizes the automatic adjustment of the volume ratio of functional zones through the innovative movable partition system, precise sensor network and intelligent control algorithm, effectively responds to the fluctuation of influent water quality, maintains stable nitrogen and phosphorus removal effect, reduces energy consumption, reduces land occupation area and improves overall system efficiency.

[0139] Compared with the traditional fixed structure of biological reactor, the present application has obvious advantages in treating wastewater with large fluctuation of influent water quality, and is especially suitable for urban wastewater treatment and industrial wastewater treatment with obvious seasonal changes.

Claims

1. A hybrid zone variable bioreactor wastewater treatment process, characterized in that, The method comprises the following steps: introducing wastewater to be treated into a single reactor with adjustable aerobic, anoxic and anaerobic zones; real-time detection of water quality parameters of influent by online monitoring equipment, the parameters including COD, ammonia nitrogen, total nitrogen and total phosphorus concentration; automatic adjustment of the volume ratio of the aerobic, anoxic and anaerobic zones by a central control system based on the water quality parameters of influent, the volume ratio adjustment being realized by movable partitions; adjustment of aeration intensity and internal reflux ratio according to real-time monitored dissolved oxygen, oxidation-reduction potential and pH value in each functional zone; nitrification reaction in the aerobic zone to convert ammonia nitrogen into nitrate nitrogen; denitrification reaction in the anoxic zone to convert nitrate nitrogen into nitrogen gas; realization of enhanced biological phosphorus removal by the alternative action of the anaerobic and aerobic zones; discharge of treated wastewater from the system; the central control system adopts a multi-level control strategy, including: a basic control loop for maintaining the dissolved oxygen concentration in the aerobic zone at 1.5-3.5 mg / L, the mixing intensity at 5-15 W / m3 and the reflux ratio at 100%-400% of the influent flow rate; zone volume optimization control for dynamically adjusting the zone volume based on nitrogen removal requirements, with a response time of 15-60 minutes; predictive control for adjusting prediction according to historical performance data and influent mode identification by using a machine learning algorithm, with a prediction adjustment time of 1-12 hours; the control system uses a fuzzy logic controller to adjust the zone volume, and determines the optimal zone configuration based on the influent and effluent water quality parameters.

2. The sewage treatment process according to claim 1, characterized in that, the movable partitions are adjusted in position by a precision drive system, which comprises: a DC brushless motor with a rated power of 0.25-1.0 kW; a planetary reduction gearbox with a reduction ratio of 50:1 to 100:1; a stainless steel screw rod with a pitch of 5-10 mm; a ceramic-coated aluminum linear guide rail with a load capacity of 50-200 kg; the positioning accuracy of the precision drive system is ±5 mm, and the moving speed is 5-20 mm / min.

3. The sewage treatment process according to claim 1, characterized in that, the online monitoring equipment comprises: a dissolved oxygen sensor using optical luminescence method, with a measurement range of 0-20 mg / L and an accuracy of ±0.1 mg / L; an ammonia nitrogen sensor using an ion-selective electrode, with a measurement range of 0-100 mg / L and an accuracy of ±3%; a nitrate nitrogen sensor using ultraviolet absorption method, with a measurement range of 0-100 mg / L and an accuracy of ±5%; a phosphate sensor using colorimetric method, with a measurement range of 0-20 mg / L and an accuracy of ±2%; a glass electrode pH sensor, with a measurement range of pH 4-10 and an accuracy of ±0.1 unit; a platinum electrode oxidation-reduction potential sensor, with a measurement range of -500 to +500 mV and an accuracy of ±5 mV; a mixed liquid suspended solid concentration sensor using near-infrared absorption method, with a measurement range of 0-15 g / L and an accuracy of ±5%.

4. The sewage treatment process according to claim 1, characterized in that, the aeration system of the aerobic zone comprises: a diaphragm-type micro-porous aerator made of EPDM, with a bubble size of 1-3 mm; a PVC frame with a maximum pressure-bearing capacity of 100 kPa; an ABS material distribution pipe with a gas flow rate of 2-12 Nm3 / h·m2; The aeration system has an oxygen transfer efficiency of 3.0-4.5 kg O2 / kWh at 20℃ in clean water under standard conditions, and the density of aerators is 10%-15% of the bottom area.

5. The sewage treatment process according to claim 1, characterized in that, The anoxic zone adopts a moderate bubble mixing system, which comprises: Aerator made of HDPE, with bubble size of 5-8 mm; PVC 80 grade distribution pipe, with gas flow of 0.5-2.0 Nm3 / h·m2; The mixing system provides gentle mixing without excessive oxygen transfer, so that the dissolved oxygen level in the anoxic zone is maintained at 0.1-0.5 mg / L.

6. The sewage treatment process according to claim 1, characterized in that, The anaerobic zone adopts a hydraulic mixing system, which comprises: 316L stainless steel submersible agitator, with motor power of 0.25-1.0 kW; Glass fiber reinforced polypropylene impeller, with diameter of 200-400 mm; Rotational speed of 50-150 rpm; The mixing system provides power input of 5-10 W / m3, preventing oxygen introduction while ensuring uniform distribution of biomass.

7. The sewage treatment process according to claim 1, characterized in that, The process parameters of each functional zone are as follows: Oxic zone: dissolved oxygen of 1.5-3.5 mg / L, oxidation-reduction potential of +100 to +300 mV, pH value of 6.8-7.8, hydraulic retention time of 4-12 hours, mixed liquor suspended solids concentration of 3.0-5.0 g / L; Anoxic zone: dissolved oxygen of 0.1-0.5 mg / L, oxidation-reduction potential of -50 to +50 mV, pH value of 6.8-7.8, hydraulic retention time of 2-6 hours, mixed liquor suspended solids concentration of 3.0-5.0 g / L; Anaerobic zone: dissolved oxygen of less than 0.1 mg / L, oxidation-reduction potential of -100 to -250 mV, pH value of 6.5-7.5, hydraulic retention time of 1-3 hours, mixed liquor suspended solids concentration of 3.0-5.0 g / L.

8. The sewage treatment process according to claim 1, characterized in that, The overall system parameters of the process include: Total hydraulic retention time of 8-24 hours; Solid retention time of 10-30 days; F / M ratio of 0.05-0.15 kg BOD / kg MLVSS·day; Internal reflux ratio of 100%-400% of influent flow rate; Reflux activated sludge ratio of 50%-100% of influent flow rate; Residual sludge discharge rate of 3%-10% of system volume per day.

9. The sewage treatment process according to claim 1, characterized in that, It also includes an optional biofilm carrier medium reinforcement system, wherein the biofilm carrier medium is made of HDPE, with specific surface area of 500-1000 m2 / m3, density of 0.95-0.98 g / cm3, filling ratio of 15%-40% of the zone volume, and biofilm thickness of 0.1-2.0 mm; the carrier medium provides an attachment surface for immobilized professional microbial communities, enhancing nitrification in the oxic zone and denitrification in the anoxic zone.

Images