Self-adaptive multi-medium composite filtering device and filtering method thereof

Abstract

The invention belongs to the technical field of sewage treatment, and particularly discloses a self-adaptive multi-medium composite filtering device and a filtering method thereof. The device comprises a multi-layer composite filter layer, a sensor, an automatic backwashing system and a control system, based on cooperative work of the multi-layer composite filter layer and an intelligent regulation and control system, after to-be-treated sewage is intercepted and adsorbed by the multi-layer filter layer in gradient distribution in a layered manner, the sensor collects water quality and filter layer state data in real time; and the intelligent control system dynamically adjusts the porosity of the filter layer based on preset logic, and triggers'on-demand backwashing ', so that efficient purification of complex water is realized. The problems of low efficiency, poor impact resistance and high backwashing energy consumption of a traditional filtering technology are solved, the effluent turbidity is smaller than or equal to 5 NTU, the COD removal rate is larger than or equal to 45%, the comprehensive operation cost is reduced by 40% or above, and the method is suitable for industrial sewage pretreatment, domestic sewage deep filtration and reclaimed water reuse.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, in particular to a self-adaptive multi-medium composite filtration method and device, which is suitable for industrial wastewater pretreatment, domestic sewage advanced filtration and reclaimed water reuse treatment and the like scenes, and has a remarkable filtration effect on complex water quality containing suspended particles, colloidal substances and trace organic pollutants. BACKGROUND

[0002] Sewage filtration is a key pretreatment link in the sewage treatment process, and its efficiency directly affects the operation stability and treatment cost of the subsequent treatment process. An efficient filtration system can not only effectively remove suspended solids and colloidal particles, but also reduce the load of the subsequent biochemical treatment unit, ensuring the efficient operation of the entire sewage treatment system.

[0003] However, the current mainstream filtration technology still has many shortcomings and is difficult to meet the increasingly complex water quality treatment requirements. Traditional single medium filtration devices such as quartz sand filter have poor adaptability to complex water quality. For example, when treating chemical wastewater containing colloidal particles with a particle size of 0.1-1 μm, the filtration efficiency is only 30%-40%, and the filter layer is easily clogged. Usually, the filter layer needs to be frequently backwashed within 2-3 hours, resulting in that the backwashing water consumption accounts for 8%-12% of the total treatment water quantity, causing waste of water resources. In addition, although the fiber filter cloth filter has good suspended particle interception effect, the removal rate of organic pollutants such as COD is less than 20%, which cannot meet the requirement of comprehensive purification. More importantly, the fiber filter cloth filter is particularly vulnerable when facing water quality fluctuations. For example, when the influent turbidity suddenly increases from 10 NTU to 50 NTU, the probability of over-standard effluent turbidity is as high as 60% or more, which seriously affects the stability of the subsequent treatment process.

[0004] Although the existing multi-medium filtration device can consider both particle interception and adsorption functions, it has structural defects such as fixed medium ratio and unadjustable layer height, which seriously affects its ability to respond to dynamic changes in water quality. When the composition of pollutants in the influent changes, such as the intermittent discharge of industrial wastewater leading to a sudden increase in oil substances, the filtration layer structure cannot be dynamically adjusted, resulting in a reduction of more than 50% in the filtration period. More importantly, relying on manual medium adjustment not only has a lag response (usually requiring several hours of downtime), but also increases the labor cost by 30%-50%, which is difficult to meet the needs of continuous and intelligent operation of modern water plants.

[0005] In addition, the backwash of the conventional filtration system is usually controlled by time, rather than triggered according to the actual clogging state, and the phenomena of "over-washing" or "insufficient washing" often occur. Data shows that in the time-controlled backwash mode, about 40% of the backwash operations are invalid energy consumption, and the recovery rate of the filter layer after backwash is only 60%-70%, further reducing the filtration efficiency. In addition, frequent invalid backwash operations increase the wear and maintenance frequency of the equipment, leading to an increase in the overall operating cost and affecting the overall economy.

[0006] In summary, the existing technology cannot meet the filtration requirements of high efficiency, stability and low consumption under complex water quality. Therefore, it is urgent to develop a new type of filtration device that can adapt to changes in water quality and dynamically optimize filtration parameters. SUMMARY

[0007] The main purpose of the present application is to provide a self-adaptive multi-medium composite filtration device and a filtration method thereof, which solves the technical problems of low filtration efficiency, poor impact load resistance, easy clogging, high backwash energy consumption, frequent operation and maintenance, etc. existing in the prior art. The device integrates multiple layers of gradient filter layers, support frames, real-time sensing and intelligent control systems, automatically adjusts the filtration parameters according to the dynamic changes of the inlet water quality and the operation state of the filter layer, realizes continuous operation with high efficiency, stability and energy saving, and significantly improves the reliability and economy of the sewage treatment system.

[0008] To solve the above technical problems, the technical scheme adopted by the present application is: A self-adaptive multi-medium composite filtration device, comprising a filter housing, a plurality of composite filter layers are arranged inside the filter housing for step-by-step purification treatment of sewage; a water inlet pipe is arranged at the top of the filter housing, the end of which is connected to a water distributor to ensure uniform distribution of the inlet water; a water outlet pipe and a sewage discharge pipe are arranged at the bottom of the filter housing, the water outlet pipe discharges the filtered sewage, and the sewage discharge pipe is used for discharging backwash wastewater; a pressure sensor is arranged on the side wall of the filter housing for monitoring the pressure difference before and after the filtration of the filter layer and observing the clogging degree of the filter layer; an automatic backwash system and an intelligent control system are arranged at the bottom of the housing, and the control system is electrically connected with the pressure sensor and the automatic backwash system for dynamically adjusting the filling density of the multi-layer composite filter layer and controlling the backwash operation based on the sensor data.

[0009] Preferably, a first turbidity sensor, a COD online monitor and a flow sensor are arranged on the water inlet pipe for real-time monitoring of the water quality parameters of the inlet; a second turbidity sensor and a pH sensor are arranged on the water outlet pipe for monitoring the water quality of the outlet.

[0010] Preferably, the collection frequency of all sensors is 10 s / time, the turbidity measurement range is 0-1000 NTU (accuracy ±1%), the COD online monitor measurement range is 0-1000 mg / L, the flow sensor accuracy is ±0.5%, the pressure sensor measurement range is 0-1 MPa (accuracy ±0.2% FS), and the pH measurement range is 0-14 (accuracy ±0.02 pH).

[0011] Preferably, the control system is electrically connected with the first turbidity sensor, the COD online monitor, the flow sensor, the second turbidity sensor, and the pH sensor, and can dynamically adjust the packing density of the multi-layer composite filter layer and perform backwashing operation based on the data of the sensors.

[0012] Preferably, the side of the filter shell is provided with a support frame composed of 10-20 parallel crossbars, the crossbars are connected with the inner wall of the shell through an adjusting mechanism, the adjusting mechanism is electrically connected with the intelligent control system, the response time is ≤2 s, and the crossbar spacing is dynamically adjusted under the instruction of the intelligent control system.

[0013] Preferably, the initial crossbar spacing is set to 5-15 mm, the adjusting accuracy is ±0.1 mm, the adjusting range is ±2 mm, the packing density and porosity of the filter medium are accurately controlled by changing the crossbar spacing, and the filtering performance is optimized.

[0014] Preferably, the automatic backwashing system adopts a gas-water combined flushing mode, includes a backwashing water pump (lift 30-50 m), a top annular water distribution pipe, and an electromagnetic valve group, the gas flushing intensity is 15-20 L / (m 2 ·s), the water flushing intensity is 8-12 L / (m 2 ·s), the cleaning is thorough and the energy consumption is low, the triggering time and duration of backwashing are dynamically calculated by the control system to avoid invalid flushing.

[0015] Preferably, at least one gas flushing channel is arranged at the bottom of the filter shell, under the action of the automatic backwashing system, gas is flushed to the filter layer to remove blockages; at the same time, the porosity of the filter medium is adjusted through the adjusting mechanism, so that the blockages are separated from the filter layer and then discharged from the filter shell.

[0016] Preferably, the filter shell is a vertical cylindrical structure with a diameter of 1-3 m and a height of 2-5 m, and is made of 316L stainless steel with corrosion-resistant treatment of the inner wall.

[0017] Preferably, the multi-layer composite filter layer includes, from bottom to top: a support layer composed of gravel with a particle size of 20-30 mm, a thickness of 100-150 mm, and serving to support the filter material and uniformly distribute water; Quartz sand layer: quartz sand filter material with a particle size of 0.8-1.2 mm is used, the thickness is 300-400 mm, and ≥1 μm suspended particles are efficiently intercepted; Activated carbon layer: granular activated carbon with an iodine value of ≥1000 mg / g is filled, the thickness is 200-300 mm, and dissolved organic matter, color and odor are adsorbed, and the COD removal rate is improved; Fine filtration layer: the fine filtration layer is composed of modified fiber filter cloth and honeycomb porous ceramic, and the total thickness is 150-230 mm, so that colloids and small particles are finely intercepted, and uniform water flow distribution is ensured.

[0018] Preferably, the pore size of the modified fiber filter cloth 2041 is 5-10 μm, and the porosity of the honeycomb porous ceramic is 60%-70%.

[0019] Preferably, the intelligent control system uses a high-performance PLC controller (main frequency ≥1 GHz, memory ≥1 GB), integrates a data acquisition module and an execution control module, and forms a closed-loop control circuit, and the operation adjustment logic is as follows: 1) Data acquisition: the turbidity T, COD concentration C, filter layer pressure difference ΔP and effluent turbidity T of the influent are collected in real time with a period of 10 s 出水 and other key parameters; 2) Adjustment and judgment: the real-time data are compared with the preset threshold value, when ΔP> ΔP0 (ΔP0 is 50-80 kPa) or T> T0 (T0 is 20-50 NTU), the parameter adjustment mechanism is triggered; 3) Dynamic adjustment: the support frame spacing adjustment amount S is dynamically calculated by the following empirical formula: wherein k1 is the pressure coefficient (0.002-0.005 mm / kPa), k2 is the turbidity coefficient (0.01-0.03 mm / NTU), and the adjustment range of S is ±2 mm, so as to ensure the stability of the filter layer structure; The control system adjusts the filter layer density by sensing filter layer clogging (ΔP rising) and influent load impact (T rising), and the spacing S is reduced to enhance the interception capacity to cope with high load, and the spacing S is increased to reduce the pressure loss to prolong the filtration period; 4) Intelligent backwashing: when ΔP≥ΔP0+20 kPa or Tout≥10 NTU, the backwashing program is automatically triggered; the backwashing duration t (unit: s) is dynamically calculated by the following formula: to ensure that the filter layer recovery rate is ≥90%.

[0020] The second aspect of the application provides a self-adaptive multi-medium composite filtration method, which uses the self-adaptive multi-medium composite filtration device, and comprises the following steps: S1, the sewage to be filtered is introduced into the filtering device, and sequentially passes through the multiple composite filter layers from top to bottom while the operation data are collected in real time by the sensors at different positions; S2, the intelligent control system receives and analyzes the operation data, and calculates the spacing adjustment amount S of the support frame when the filter layer pressure difference ΔP is greater than a first preset threshold value ΔP0 or the water inlet turbidity T is greater than a second preset threshold value T0 is monitored; S3, the drive adjustment mechanism adjusts the spacing of the horizontal rods according to the adjustment amount S to optimize the porosity and filtering performance of the filter layer; S4, when the backwashing trigger condition is met, the automatic backwashing system is controlled to start and perform backwashing operation on the filter layer, and the washing wastewater is discharged from the bottom blowdown pipeline; S5, after the backwashing is completed, the normal filtering is resumed, and steps S2-S4 are repeated until the water quality is stable and meets the standard.

[0021] Preferably, in step S2, the calculation formula of the spacing adjustment amount S is as follows: ; Wherein, k1=0.002-0.005mm / kPa, k2=0.01-0.03mm / NTU, ΔP is the filter layer pressure difference, T is the water inlet turbidity, and T0 is the second preset threshold value.

[0022] Preferably, in step S2, the first preset threshold value ΔP0 has a value range of 50-80kPa, the second preset threshold value T0 has a value range of 20-50NTU, and the backwashing trigger condition is ΔP≥ΔP0+20kPa or Tout≥10NTU; the calculation formula of the backwashing duration t is as follows: ; wherein, the unit of t is s.

[0023] Preferably, the response time of the adjustment mechanism in step S3 is ≤2s, which ensures the real-time performance of parameter adjustment.

[0024] Preferably, in step S4, the operation process of backwashing is as follows: first, air flushing for 30s, then air-water combined flushing, and finally water flushing for 30s; wherein, the duration of the air-water combined flushing is dynamically determined by the control system.

[0025] Preferably, the water quality indexes realized by the filtering method are as follows: turbidity ≤5NTU, COD removal rate ≥45%, and suspended particle (≥1μm) removal rate ≥90%.

[0026] The beneficial effects of the present application are as follows: 1. High efficiency filtration, excellent water quality stability: The present application relies on a multi-layer composite filtration system composed of quartz sand, granular activated carbon, modified fiber filter cloth and honeycomb porous ceramic. The system adopts a gradient interception and adsorption synergistic mechanism to achieve efficient removal of pollutants. The quartz sand layer effectively intercepts large particle suspended solids, the activated carbon layer efficiently adsorbs dissolved organic matter and color, and the modified fiber filter cloth and porous ceramic realize fine filtration of colloids and small particles. This structure significantly improves the overall filtration precision, with a removal rate of ≥90% for particles ≥1 μm, a COD removal rate of ≥45%, and a stable effluent turbidity of ≤5 NTU. Compared with traditional quartz sand filter, the filtration efficiency is improved by more than 60%; compared with existing fixed ratio multi-media filter, under the same influent conditions, the stability and compliance rate of effluent water quality are improved by more than 30%, and the filtration performance is significantly better than existing technology.

[0027] 2. Strong self-adaptive ability and outstanding impact load resistance: The device integrates real-time monitoring systems for multiple parameters such as influent turbidity, COD, filter layer pressure difference and effluent water quality, combined with an intelligent feedback control system, automatically adjusts the spacing between support frames according to dynamic changes in water quality, thereby optimizing filter layer porosity and interception capacity. This adaptive mechanism enables the system to have excellent impact load resistance, with an effluent compliance rate of ≥98% under wide range fluctuations of influent turbidity 5-50 NTU and COD 100-500 mg / L; effectively solves the technical problems of traditional filtration equipment, such as effluent exceeding standard and unstable operation when water quality suddenly changes, significantly improves the adaptability and reliability of the system under complex conditions such as intermittent discharge of industrial wastewater and fluctuation of water quantity in rainy season, and provides strong guarantee for stable operation of subsequent treatment processes.

[0028] 3. Significant energy saving and consumption reduction: The present application adopts an intelligent backwashing mechanism of "on-demand triggering", determines the washing time based on filter layer pressure difference and effluent water quality, avoids the problems of "excessive washing" or "insufficient washing" in traditional timed backwashing mode, and combines with efficient "air-water combined washing" mode to significantly improve washing efficiency. Compared with traditional timed backwashing, backwashing water consumption is reduced by 50%-70%, energy consumption is reduced by 40%-50%, and single washing time is shortened by more than 30%. Based on a single device (20h daily operation), annual electricity saving can reach 15,000 degrees, annual water saving exceeds 2,500 tons, and comprehensive operation cost decreases by more than 40%, with significant energy saving and consumption reduction and resource saving benefits.

[0029] 4. The filter material life is extended, and the maintenance cost is greatly reduced: through the dynamic adjustment function of the support frame, the system can moderately compress the filter layer to enhance the interception capacity under high load operation, and restore the loose structure of the filter layer after low load or backwashing, effectively avoiding the hardening and channeling phenomenon caused by long-term compaction of the filter material; this structure significantly reduces the risk of mechanical wear and breakage between filter materials, reduces the overall wear rate of filter materials by more than 60%, extends the medium replacement cycle from 3 months of traditional equipment to 8-12 months, greatly reduces the frequency of downtime maintenance and spare parts replacement cost; at the same time, the maintenance labor input and system downtime loss are significantly reduced, the comprehensive maintenance cost is reduced by more than 60%, and the continuous operation capacity and life cycle economy of the equipment are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] The application will be further described below in conjunction with the drawings: Figure 1 is a structural schematic diagram of the adaptive multi-medium composite filtration device of the application; In the figure: support frame 1, crossbar 101, adjustment mechanism 102; multi-layer composite filter layer 2, support layer 201, quartz sand layer 202, activated carbon layer 203, fine filter layer 204, modified fiber filter cloth 2041, honeycomb porous ceramic 2042; water inlet pipe 3, first turbidity sensor 301, COD online monitor 302, flow sensor 303, water distributor 304; air flushing channel 4; water outlet pipe 5, second turbidity sensor 501, pH sensor 502; sewage pipe 6, annular water distributor 601; pressure sensor 7; automatic backwashing system 8; intelligent control system 9. DETAILED DESCRIPTION

[0031] The technical solutions of the application will be further described below in conjunction with specific embodiments.

[0032] As shown in Figure 1 , an adaptive multi-medium composite filtration device, comprising a filter housing, a multi-layer composite filter layer 2 is arranged inside the filter housing for step-by-step purification treatment of sewage; the top of the filter housing is provided with a water inlet pipe 3, the end of which is connected to a water distributor 304 to ensure uniform distribution of the inlet water; the bottom is provided with a water outlet pipe 5 and a sewage pipe 6, the water outlet pipe 5 discharges the filtered sewage; the sewage pipe 6 is used for discharging backwashing wastewater; the sidewall of the filter housing is provided with a pressure sensor 7 for monitoring the pressure difference before and after the filtration of the filter layer and observing the degree of filter layer blockage; the bottom of the housing is provided with an automatic backwashing system 8 and an intelligent control system 9, the intelligent control system 9 is electrically connected with the pressure sensor 7 and the automatic backwashing system 8, and is used for dynamically adjusting the filling density of the multi-layer composite filter layer and controlling the backwashing operation based on the sensor data.

[0033] As a preferred technical solution, the water inlet pipeline is provided with a first turbidity sensor 301, a COD online monitor 302 and a flow sensor 303 for real-time monitoring of water quality parameters at the water inlet; the water outlet pipeline is provided with a second turbidity sensor 501 and a pH sensor 502 for monitoring the water quality at the water outlet.

[0034] The collection frequency of all sensors is 10s / time, the turbidity measurement range is 0-1000NTU (accuracy ±1%), the COD online monitor measurement range is 0-1000mg / L, the flow sensor accuracy is ±0.5%, the pressure sensor measurement range is 0-1MPa (accuracy ±0.2%FS), and the pH measurement range is 0-14 (accuracy ±0.02pH).

[0035] The control system 9 is electrically connected with the first turbidity sensor 301, the COD online monitor 302, the flow sensor 303, the second turbidity sensor 501 and the pH sensor, and can dynamically adjust the packing density of the multi-layer composite filter layer and perform backwashing operation based on the data of the sensors.

[0036] As a preferred technical solution, the side of the filter shell is provided with a support frame 1 composed of 10-20 parallel arranged cross bars 101, the cross bars 101 are connected with the inner wall of the shell through an adjusting mechanism 102, the adjusting mechanism 102 is electrically connected with the intelligent control system 9, and the response time is ≤2s, which dynamically adjusts the cross bar spacing under the instruction of the control system 9.

[0037] The initial spacing of the cross bars 101 is set to 5-15mm, the adjusting accuracy is ±0.1mm, and the adjustment range is ±2mm, so as to accurately control the packing density and porosity of the filter medium by changing the cross bar spacing, thereby optimizing the filtering performance.

[0038] As a preferred technical solution, the automatic backwashing system 8 adopts a gas-water combined flushing mode, including a backwashing water pump (head 30-50m), a top annular water distribution pipe 601 and an electromagnetic valve group, the gas flushing intensity is 15-20L / (m 2 ·s), the water flushing intensity is 8-12L / (m 2 ·s), the cleaning is thorough and the energy consumption is low; the triggering time and duration of backwashing are dynamically calculated by the control system to avoid invalid flushing.

[0039] As a preferred technical solution, the filter shell bottom is provided with at least one gas flushing channel 4, which removes the blockage under the action of the automatic backwashing system 8; at the same time, the porosity of the filter medium is adjusted through the adjusting mechanism 102, so that the blockage is separated from the filter layer and then discharged from the filter shell.

[0040] As a preferred technical solution, the filter housing is a vertical cylindrical structure with a diameter of 1-3m and a height of 2-5m. It is made of 316L stainless steel and the inner wall is treated with anti-corrosion.

[0041] As a preferred technical solution, the multi-layer composite filter layer 2 comprises, from bottom to top: The support layer 201 is composed of gravel with a particle size of 20-30mm and a thickness of 100-150mm. It serves to support the filter media and distribute water evenly. Quartz sand layer 202 is composed of quartz sand filter media with a particle size of 0.8-1.2mm and a thickness of 300-400mm, and is used to efficiently intercept large-diameter suspended particles. Activated carbon layer 203, composed of granular activated carbon with an iodine value ≥1000mg / g and a thickness of 200-300mm, is used to adsorb dissolved organic pollutants, odors and some color, and is measured by COD removal rate; The fine filter layer 204 is composed of modified fiber filter cloth 2041 (pore size 5-10μm) and honeycomb porous ceramic 2042 (porosity 60%-70%), with a total thickness of 150-230mm. It is used to finely intercept colloids and small particles and ensure uniform water distribution, thus ensuring uniform water flow.

[0042] As a preferred technical solution, the intelligent control system 9 adopts a high-performance PLC controller (main frequency ≥ 1GHz, memory ≥ 1GB), integrating a data acquisition module and an execution control module to form a closed-loop control circuit. Its adaptive adjustment logic is as follows: 1) Data Acquisition: Real-time acquisition of influent turbidity T, COD concentration C, filter bed pressure difference ΔP, and effluent turbidity T at 10-second intervals. 出水 Key parameters; 2) Adjustment judgment: Compare real-time data with preset thresholds. When ΔP > ΔP0 (ΔP0 is 50-80 kPa) or T > T0 (T0 is 20-50 NTU), trigger the parameter adjustment mechanism. 3) Dynamic adjustment: The adjustment amount S of the support frame spacing is dynamically calculated using the following empirical formula: Where k1 is the pressure coefficient (0.002-0.005 mm / kPa), k2 is the turbidity coefficient (0.01-0.03 mm / NTU), and S is adjusted within the range of ±2 mm to ensure the stability of the filter layer structure; The control system adjusts the filter bed density in a coordinated manner by sensing filter bed blockage (ΔP increase) and influent load shock (T increase). Decreasing the spacing S can enhance the interception capacity to cope with high load, while increasing S can reduce pressure loss and extend the filtration cycle. 4) Intelligent backwashing: when ΔP ≥ ΔP0 + 20 kPa or Tout ≥ 10 NTU, the backwashing program is automatically triggered; the backwashing duration t (unit: s) is dynamically calculated by the following formula: , ensuring that the recovery rate of the filter layer is ≥ 90%.

[0043] The application further provides a self-adaptive multi-medium composite filtering method, which uses the self-adaptive multi-medium composite filtering device and comprises the following steps: S1. Filtration: the wastewater to be treated enters the filtering device through the water inlet pipeline, and is sequentially subjected to the action of the multiple composite filter layers, so that the suspended particles are intercepted and the organic pollutants are adsorbed, and the filtered water is discharged from the water outlet pipeline; S2. Monitoring: the sensor group collects data every 10 s, and transmits the data to the control system for analysis; S3. Self-adaptive adjustment: the control system compares the real-time data with the preset threshold value, calculates the support frame spacing adjustment amount through the formula S = k1 x ΔP + k2 x (T - T0), drives the adjusting mechanism to change the cross bar spacing, and optimizes the filter layer porosity; S4. Backwashing: when the backwashing condition is met, the control system closes the water inlet valve, opens the backwashing system, and operates according to the process of “air flushing for 30 s → air-water combined flushing for 60 s → water flushing for 30 s”, and the flushing wastewater is discharged from the bottom blowdown pipeline; S5. Recovery: after the backwashing is completed, normal filtration is resumed, and steps S2-S4 are repeated until the water quality is stable and meets the standard (Tout ≤ 5 NTU, and the COD removal rate is ≥ 40%) The technical effects of the application are further described in combination with specific embodiments.

[0044] Embodiment 1 Taking the pretreatment of the comprehensive wastewater in a chemical industrial park as an example, the wastewater contains benzene series, suspended particles (1-50 μm) and colloidal substances, and the water quality parameters are: turbidity 35 NTU, COD 320 mg / L, pH 6.5-7.2, and water volume 500 m 3 / h.

[0045] The self-adaptive multi-medium composite filtering device (diameter 2 m, height 4 m) of the application is adopted, in the composite multiple filter layers of the device, the gravel supporting layer is 120 mm, the quartz sand layer is 350 mm, the activated carbon layer is 250 mm, the fiber filter cloth layer is 60 mm, and the porous ceramic layer is 120 mm. The embodiment provides a self-adaptive multi-medium composite filtering method, which comprises the following steps: S1, initialization and filtration (0-2 h): Set initial parameters: support frame crossbar spacing S0=10mm, first preset threshold ΔP0=60kPa, second preset threshold T0=30NTU, k1=0.003mm / kPa, k2=0.02mm / NTU; The sewage to be treated flows into the filter device from the water inlet pipeline, passes through each filter layer in turn, and is discharged from the water outlet pipeline after purification. The turbidity of the sewage is 4.2NTU, and the COD removal rate is 48%. S2, real-time monitoring (0-2h): the intelligent control system continuously collects the inlet water turbidity T and COD concentration, the pressure difference ΔP of the filter layer, and the outlet water turbidity Tout at a cycle of 10s; S3, adaptive adjustment judgment and execution (2-2.5h): the control system compares the real-time data with the threshold value. In the stable operation stage, no adjustment is triggered; In the water quality fluctuation stage: when the workshop intermittent drainage causes the inlet water turbidity to rise to 48NTU and the COD to rise to 380mg / L, and ΔP rises to 65kPa within 30min; at this time, T>T0 and ΔP>ΔP0, the control system enters the adjustment step, and the control system calculates the spacing adjustment amount S according to the formula: The calculation result shows that the crossbar spacing S needs to be reduced by 0.375mm. Subsequently, the control system immediately drives the adjustment mechanism to adjust the crossbar spacing from 10mm to 9.625mm. This operation slightly compacts the entire filter layer, reduces the porosity, and thus enhances the interception capacity of pollutants under the impact of the inlet water load, prevents the penetration of pollutants, and ensures the water quality of the outlet water; S4, intelligent backwashing judgment and execution (4h): as the filtration proceeds, the filter layer pressure difference continuously rises. When ΔP reaches 82kPa (i.e. ≥ΔP0+20kPa), the backwashing trigger condition is met, and the control system dynamically calculates the backwashing duration: ; Subsequently, the control system closes the water inlet pipeline, starts the automatic backwashing system, and operates according to the program of "air flushing for 30s→air-water combined flushing for 41s→water flushing for 30s". The flushing wastewater is discharged from the blowdown pipeline. The flushing duration is determined according to the actual plugging degree, so as to maximize the flushing efficiency and minimize the resource consumption; S5, system recovery (4.2h): after backwashing, ΔP drops to 28kPa, the outlet water turbidity is 3.8NTU, and the COD removal rate is 49%. The control system restores the support frame spacing to the initial 10mm, reopens the water inlet, and the system enters the next filtration cycle, repeating steps S2-S4.

[0046] The above system operation results show that the filtration effect is optimized by controlling the parameters of each step.

[0047] Comparative Example 1: ​The comparative example uses a traditional quartz sand filter device to filter sewage: under the same water quality fluctuation as Example 1, the effluent turbidity rises to 12.5 NTU (exceeding the standard), the ΔP reaches 80 kPa within 3 h, and backwashing is required every 3 h (water consumption of 15 m 3 ).

[0048] Compared with Comparative Example 1, the filtration device of the application is used to filter sewage, and the backwashing period is extended to 4 h, but the single water consumption is 9 m 3 , and the effluent always meets the standard. After one month of operation, the wear rate of the filtration medium of the device is only 3%, and that of the traditional device is 12%, significantly reducing the medium replacement cost.

[0049] The above results show that the self-adaptive multi-medium filtration device of the application can effectively cope with water quality fluctuations, has stable filtration efficiency, reduces operation cost by 42%, and fully meets the water inlet requirements (turbidity ≤ 10 NTU, COD ≤ 300 mg / L) of subsequent biochemical treatment.

[0050] The above examples are only preferred technical solutions of the application, and should not be regarded as limiting the application. The protection scope of the application should be based on the technical solutions recited in the claims, including equivalent replacement solutions of the technical features recited in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the application.

Claims

1. An adaptive multi-medium composite filtration device, characterized by, The application relates to a multi-layer composite filter for sewage treatment, which comprises a filter shell, a plurality of multi-layer composite filter layers (2) arranged in the filter shell, and a water inlet pipe (3) arranged at the top of the filter shell and connected with a water distributor (304) at the tail end to ensure uniform distribution of the water; a water outlet pipe (5) and a sewage discharge pipe (6) are arranged at the bottom of the filter shell, the water outlet pipe (5) is used for discharging filtered sewage, and the sewage discharge pipe (6) is used for discharging backwashing waste water; a pressure sensor (7) is arranged on the sidewall of the filter shell and used for monitoring the pressure difference before and after the filtration of the filter layer and observing the plugging degree of the filter layer; an automatic backwashing system (8) and an intelligent control system (9) are arranged at the bottom of the shell, the control system (9) is electrically connected with the pressure sensor (7) and the automatic backwashing system (8), and the control system (9) is used for dynamically adjusting the filling density of the multi-layer composite filter layer and controlling the backwashing operation based on the sensor data.

2. The self-adapting multi-medium composite filtration device according to claim 1, wherein, A first turbidity sensor (301), a COD online monitor (302) and a flow sensor (303) are arranged on the water inlet pipe and used for monitoring the water quality parameters of the water inlet in real time; a second turbidity sensor (501) and a pH sensor (502) are arranged on the water outlet pipe and used for monitoring the water quality of the water outlet.

3. The self-adapting multi-medium composite filtration device according to claim 2, wherein, The collection frequency of all the sensors is 10s / time, the turbidity measurement range is 0-1000NTU (the accuracy is + / -1%), the COD online monitor measurement range is 0-1000mg / L, the flow sensor accuracy is + / -0.5%, the pressure sensor measurement range is 0-1MPa (the accuracy is + / -0.2%FS), and the pH measurement range is 0-14 (the accuracy is + / -0.02pH).

4. The self-adapting multi-medium composite filtration device according to claim 1, wherein, A supporting frame (1) composed of 10-20 parallel transverse rods (101) is arranged at the side of the filter shell, the transverse rods (101) are connected with the inner wall of the shell through adjusting mechanisms (102), the adjusting mechanisms (102) are electrically connected with the intelligent control system (9), the response time is less than or equal to 2s, and the transverse rod spacing is dynamically adjusted under the instruction of the control system (9).

5. The self-adapting multi-medium composite filtration device according to claim 5, wherein, The initial spacing of the transverse rods (101) is 5-15mm, the adjusting accuracy is + / -0.1mm, and the adjusting range is + / -2mm.

6. The self-adapting multi-medium composite filtration device according to claim 1, wherein, The automatic backwash system (8) adopts a gas-water combined flushing mode, contains a backwash water pump, a top annular water distribution pipe (601) and an electromagnetic valve group, the gas flushing intensity is 15-20 L / (m 2 ·s), the water flushing intensity is 8-12 L / (m 2 ·s), cleaning is thorough and energy consumption is low.

7. The self-adapting multi-medium composite filtration device according to claim 1, wherein, The multi-layer composite filter layer (2) comprises the following from bottom to top: A supporting layer (201) composed of gravel with a particle size of 20-30mm and having a thickness of 100-150mm; A quartz sand layer (202) adopting quartz sand filter material with a particle size of 0.8-1.2mm and having a thickness of 300-400mm; An activated carbon layer (203) filled with granular activated carbon with an iodine value of greater than or equal to 1000mg / g and having a thickness of 200-300mm; A precision filter layer (204) composed of modified fiber filter cloth (2041) and honeycomb-shaped porous ceramics (2042) and having a total thickness of 150-230mm.

8. The self-adapting multi-medium composite filtration method according to claim 1, using the filtration device according to any one of claims 1-9, characterized in that, The application further relates to a sewage treatment method, which comprises the following steps: S1, filtered sewage is introduced into the filter device and sequentially passes through the multi-layer composite filter layer from top to bottom, and meanwhile, operation data are collected in real time through sensors at different positions; S2, the intelligent control system receives and analyzes the operation data, when it is monitored that the filter layer pressure difference ΔP > the first preset threshold value ΔP0 or the water inlet turbidity T > the second preset threshold value T0, the spacing adjustment amount S of the support frame is calculated; S3, the driving adjustment mechanism adjusts the cross bar spacing according to the adjustment amount S, and optimizes the porosity and filtering performance of the filter layer; S4, when the backwashing trigger condition is met, the automatic backwashing system is controlled to start and backwash the filter layer, and the washing wastewater is discharged from the bottom blowdown pipeline; S5, after backwashing, normal filtration is resumed, and steps S2-S4 are repeated until the water quality is stable and up to standard.

9. The adaptive multi-medium composite filtering method of claim 1, wherein, In step S2, the calculation formula of the spacing adjustment amount S is as follows: ； Wherein, k1=0.002-0.005mm / kPa, k2=0.01-0.03mm / NTU, ΔP is the filter layer pressure difference, T is the water inlet turbidity, and T0 is the second preset threshold value.

10. The adaptive multi-medium composite filtration method according to claim 1, characterized in that, In step S2, the value range of the first preset threshold value ΔP0 is 50-80kPa, the value range of the second preset threshold value T0 is 20-50NTU, the backwashing trigger condition is ΔP≥ΔP0+20kPa or Tout≥10NTU; and the calculation formula of the backwashing duration t is: ; where t is in s.

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