Biological-ecological synergistic purification system for municipal road runoff pollutants

Abstract

The invention relates to a biological-ecological collaborative purification system for municipal road runoff pollutants, and belongs to the technical field of municipal road rainwater treatment. With the acceleration of the urbanization process, the pollution problem of municipal road runoff pollutants to natural water is increasingly serious. According to the biological-ecological collaborative purification system, the grid interception device is arranged to intercept large-particle impurities and sludge, the biological membrane reaction tank degrades pollutants by utilizing a biological membrane on a combined filler layer, the ecological filter tank further purifies water by virtue of multiple layers of filter materials and plants, and the ultraviolet disinfection device kills germs; and finally discharging the purified water into a natural water body. The method is mainly used for effectively purifying municipal road runoff pollutants and protecting natural water environment.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal road rainwater treatment. More specifically, the present invention relates to a biological-ecological collaborative purification system for runoff pollutants on municipal roads. Background Art

[0002] With the rapid development of urbanization, the construction scale of municipal roads has been continuously expanding. As one of the main sources of urban non-point source pollution, a large number of pollutants carried by municipal road runoff, such as suspended solids, organic matter, heavy metals, etc., pose a serious threat to the urban water environment.

[0003] Traditional methods for treating road runoff mainly focus on simple physical interception and sedimentation, such as setting simple grilles or sedimentation tanks at rainwater collection inlets. Although these methods can remove some large particulate suspended solids, they have poor removal effects on pollutants such as dissolved organic matter, heavy metals, and microorganisms. The reason is that traditional methods only rely on physical effects and lack a deep treatment mechanism for pollutants.

[0004] During the treatment process, there are also problems with difficult sludge treatment. If the sedimented sludge cannot be treated in a timely and effective manner, it will cause grille blockage and sedimentation tank siltation, affecting the normal operation of the treatment system. Moreover, traditional sludge treatment methods have low treatment efficiency.

[0005] In addition, for microbial pollution in road runoff, traditional treatment methods often lack effective disinfection measures. Road runoff containing a large number of germs directly discharged into natural water bodies will pose potential hazards to the water body ecological environment and human health. Therefore, it is of great practical significance to develop an efficient and stable purification system for runoff pollutants on municipal roads. Summary of the Invention

[0006] An object of the present invention is to solve at least the above problems and provide at least the advantages described hereinafter.

[0007] To achieve these objects and other advantages in accordance with the present invention, there is provided a biological-ecological collaborative purification system for runoff pollutants on municipal roads, comprising: A grille interception device, which is arranged downstream of the road rainwater collection inlet. The grille interception device includes an inclined grille, a sedimentation tank is provided at the bottom of the inclined grille, a sludge discharge pipe is connected to the bottom of the sedimentation tank, and the end of the sludge discharge pipe is connected to a sludge treatment device; Biological membrane reaction tank, whose water inlet is connected to the water outlet of the grille interception device. There is a combined packing layer in the biological membrane reaction tank. The combined packing layer is, from bottom to top, a volcanic rock packing layer with a particle size of 10 - 15 mm, a ceramsite packing layer with a particle size of 5 - 8 mm, and a polyurethane biological carrier layer with a specific surface area greater than 800 m² / m³. The total thickness of the combined packing layer is 1.2 - 1.5 m. An aeration system is provided at the bottom of the biological membrane reaction tank, and the output intensity of the aeration system is 0.8 - 1.2 m³ / (m²·h); Ecological filter tank, whose water inlet is connected to the water outlet of the biological membrane reaction tank. Inside the ecological filter tank, there is a gravel layer with a thickness of 0.5 - 0.8 m, a zeolite layer with a thickness of 0.3 - 0.5 m, and a humus soil planting layer with a thickness of 0.2 - 0.3 m arranged from bottom to top. The particle size of the gravel layer is 20 - 30 mm, the particle size of the zeolite layer is 5 - 10 mm. Reed, calamus and iris are planted in the humus soil planting layer. A perforated collecting pipe with an opening rate of 15% - 20% is provided at the bottom of the ecological filter tank; Ultraviolet disinfection device, which is installed at the water outlet end of the ecological filter tank. The water outlet of the ultraviolet disinfection device is connected to the natural water body discharge pipe.

[0008] Preferably, a transition buffer layer is provided between the volcanic rock packing layer and the ceramsite packing layer of the combined packing layer. The transition buffer layer is composed of zeolite particles with a particle size of 8 - 10 mm and a calcium ion exchange capacity ≥ 200 mg / g, and the thickness is 50 - 80 mm; The polyurethane biological carrier layer is provided with through microporous channels. The diameter of the microporous channels is 1 - 1.5 mm, and the inner wall of the microporous channels is coated with a nano - titanium dioxide photocatalytic coating with a thickness of 10 - 20 μm. The thickness of the polyurethane biological carrier layer is 0.4 - 0.6 m, and the porosity of its microporous channels ≥ 85%, and the wet compression resilience rate ≥ 90%; The aeration pipes of the aeration system form a swirling aeration structure at the bottom of the combined packing layer, and the inclination angle of the aeration holes of the aeration system is 30 - 45 degrees.

[0009] Preferably, the humus soil planting layer is composed of the following components compounded according to the mass ratio: 60% - 70% of humus soil, whose organic matter content ≥ 25% and pH is 6.0 - 7.5; 15% - 20% of modified biochar particles, with a particle size of 2 - 4 mm, a specific surface area ≥ 500 m² / g, and a surface - loaded mass fraction of 3% - 5% of Fe - Mn oxides; 10% - 15% of diatomite - zeolite composite particles, with a particle size of 1 - 3 mm and a calcium ion exchange capacity ≥ 180 mg / g; 5% - 8% of slow - release microbial inoculant particles, including nitrifying bacteria, denitrifying bacteria and plant growth - promoting rhizobacteria, with contents ≥ 1×10 6 CFU / g, ≥ 5×105 CFU / g, ≥2×10 6 CFU / g; The humus planting layer is divided into a surface layer and a bottom layer from top to bottom, the surface layer is 50-80 mm thick, the surface layer includes humus and modified biochar mixed in a mass ratio of 7:3, and reeds, calamus and irises are planted, and the three plants are distributed at a quantity ratio of 2:1:1. A spiral guide groove is set in the root zone, the spiral guide groove is 20-30 mm deep, and the groove spacing is 80-100 mm; The bottom layer is 150-220mm thick and includes humus and diatomaceous earth-zeolite composite particles mixed in a mass ratio of 6:4. Permeable expanded clay pipes with an aperture of 10-15mm are embedded inside. The horizontal spacing of the permeable expanded clay pipes is 200-250mm and the vertical spacing is 100-150mm.

[0010] Preferably, the outer periphery of the perforated water collecting pipe is wrapped with a volcanic rock particle filter layer with a particle size of 3-5 mm, the thickness of the volcanic rock particle filter layer is 80-100 mm, and the porosity of the volcanic rock particles is 45%-55%; The perforated water collecting pipe is divided into two layers, the upper perforated water collecting pipe has an opening direction facing upward and an opening rate of 15%-18%, the lower perforated water collecting pipe has an opening direction facing downward and an opening rate of 12%-15%, and the spacing between the upper and lower perforated water collecting pipes is 200-250mm.

[0011] Preferably, it also includes a backwashing system, which includes a municipal water supply pipe and an ultraviolet disinfection return water pipe connected by a three-way valve switch, and the backwashing water is reversely injected into the perforated water collecting pipe through the backwashing branch pipe, and the end of the backwashing branch pipe is connected to a sludge collection tank, and the bottom of the sludge collection tank is connected to the sludge treatment equipment through a screw conveyor; The end of the perforated water collecting pipe is connected to a backwash branch pipe, and a pressure sensor is provided on the backwash branch pipe. When it is detected that the pressure difference between the inside and outside of the water collecting pipe exceeds a set threshold, a backwash mode is triggered.

[0012] Preferably, a turbidity sensor and a flow meter are provided at the water inlet of the ultraviolet disinfection device. When the turbidity is greater than 5NTU or the flow exceeds the design value by 20%, the PLC controller synchronously controls the lamp power of the ultraviolet disinfection device to increase to 100%-110% for operation, and the overpower operation does not exceed 30 minutes at a time; A UV intensity monitoring probe is installed at the end of the UV disinfection device. When the detected dose is less than 30mJ / cm², the water flow residence time is extended to 1.2-1.5 times the original value.

[0013] Preferably, an ultrasonic level sensor is provided on the side wall of the sedimentation tank, and the height of the ultrasonic level sensor probe from the sedimentation tank bottom is 2 / 3-3 / 4 of the sedimentation tank depth, and detection is performed according to the set detection frequency; The mud discharge pipe inlet is equipped with a pneumatic knife gate valve with a gate thickness of 8-10mm; The ultrasonic liquid level sensor is connected to the PLC controller. When the sludge layer height is detected to be greater than half of the sedimentation tank depth for three consecutive times, the PLC controller controls the pneumatic knife gate valve to fully open within 15 seconds, and discharges sludge until the ultrasonic liquid level sensor detects that the sludge layer height is less than the set low threshold value, then the pneumatic knife gate valve closes. The outlet of the sludge discharge pipe is docked with the feeding port of the screw conveyor, and the discharging port of the screw conveyor is docked with the receiving bin of the sludge treatment equipment.

[0014] Preferably, three dissolved oxygen sensors are arranged at intervals along the water flow direction in the biological membrane reaction tank, which are respectively located 200 mm above the bottom of the combined packing layer, in the middle, and 150 mm below the top. The blower of the aeration system is equipped with a variable frequency controller with an output frequency of 30 - 50 Hz, and the variable frequency controller is connected to the PLC controller through a 4 - 20 mA signal. The PLC controller has a built-in segmented control algorithm. When the values of any two dissolved oxygen sensors are < 2.5 mg / L, it controls the blower frequency to rise to 40 - 45 Hz, and when the values of all three dissolved oxygen sensors are > 3.0 mg / L, it reduces the frequency to 35 - 38 Hz. A bypass pressure relief branch pipe with a solenoid valve is provided on the air outlet pipe of the blower. When the aeration intensity > 1.2 m³ / (m²·h) lasts for 5 minutes, the solenoid valve opens with an opening degree of 10% - 15%.

[0015] The present invention has at least the following beneficial effects: First, the pollutants are removed in a hierarchical and collaborative manner. The present invention integrates the functions of physical interception, biodegradation, and plant absorption, and forms a step-by-step purification chain for pollutants with different particle sizes and properties. The grille intercepts large particle impurities, the biological membrane reaction tank decomposes dissolved organic matter, and the ecological filter removes nutrient salts through the adsorption of plant roots and packing, realizing multi-dimensional pollution control.

[0016] Second, the biological and ecological functions are complementary. The high-efficiency biological membrane carrier of the combined packing layer and the root metabolism of wetland plants form a complementary effect. The microbial community stably enriches on the surface of the packing, and the root exudates of plants promote the microbial activity, while absorbing and transforming pollutants to construct a self-sustaining purification ecosystem.

[0017] Third, the dynamic operation stability is improved. The swirling aeration and the diversion channel structure optimize the hydraulic conditions and enhance the adaptability of the system to flow fluctuations. The intelligent control system automatically adjusts the aeration intensity and disinfection dose according to water quality parameters to ensure the treatment efficiency during the rainstorm period and under high pollution loads.

[0018] Fourth, it has the characteristics of long-term and low-maintenance operation. The modular packing layer design reduces the risk of blockage, and the backwashing mechanism and the automatic sludge discharge function reduce the manual maintenance requirements. The volcanic rock filter layer and the ceramsite permeable pipe structure maintain the long-term permeability performance and extend the service life of the filter tank.

[0019] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the processing equipment flow of the system of one technical solution of the present invention.

[0021] Explanation of the reference numerals in the drawings: grille interception device 100, biological membrane reaction tank 200, ecological filter tank 300, ultraviolet disinfection device 400, grille 11, sedimentation tank 12, sludge discharge pipe 13, volcanic rock packing layer 21, ceramsite packing layer 22, polyurethane biological carrier layer 23, transition buffer layer 24, aeration pipe 25, gravel layer 31, zeolite layer 32, humus soil planting layer 33, perforated water collection pipe 34, sludge collection tank 35. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following further describes the present invention in detail with reference to the drawings so that those skilled in the art can implement it according to the description in the specification.

[0023] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present invention, the orientation or positional relationship indicated by the terms is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0024] As Figure 1 shown, the present invention provides a biological-ecological collaborative purification system for municipal road runoff pollutants, including: A grille interception device 100, which is arranged downstream of the road rainwater collection port. The grille interception device 100 includes an inclined grille 11. A sedimentation tank 12 is provided at the bottom of the inclined grille 11. The bottom of the sedimentation tank 12 is connected to a sludge discharge pipe 13, and the end of the sludge discharge pipe 13 is connected to a sludge treatment device; A biological membrane reaction tank 200, whose water inlet is communicated with the water outlet of the grille interception device 100. A combined packing layer is provided in the biological membrane reaction tank 200. The combined packing layer successively includes a volcanic rock packing layer 21 with a particle size of 10-15 mm, a ceramsite packing layer 22 with a particle size of 5-8 mm, and a polyurethane biological carrier layer 23 with a specific surface area greater than 800 m² / m³ from bottom to top. The total thickness of the combined packing layer is 1.2-1.5 m. An aeration system is provided at the bottom of the biological membrane reaction tank 200, and the output intensity of the aeration system is 0.8-1.2 m³ / (m²·h); Ecological filter 300, whose inlet is connected to the outlet of the biofilm reaction tank 200. Inside the ecological filter 300, a gravel layer 31 with a thickness of 0.5 - 0.8 m, a zeolite layer 32 with a thickness of 0.3 - 0.5 m, and a humus soil planting layer 33 with a thickness of 0.2 - 0.3 m are arranged from bottom to top. The particle size of the gravel layer 31 is 20 - 30 mm, the particle size of the zeolite layer 32 is 5 - 10 mm. Reed, calamus and iris are planted in the humus soil planting layer 33. A perforated collecting pipe 34 with an opening rate of 15% - 20% is provided at the bottom of the ecological filter 300; Ultraviolet disinfection device 400, which is arranged at the water outlet end of the ecological filter 300, and the water outlet of the ultraviolet disinfection device 400 is connected to the natural water body discharge pipe.

[0025] In the above technical solution, through the synergistic effect of the grid interception device, biofilm reaction tank, ecological filter and ultraviolet disinfection device, a complete municipal road runoff pollutant treatment process is formed. The grid interception device can effectively intercept large particle impurities and sludge, preventing them from entering the subsequent treatment units; the biofilm reaction tank degrades pollutants using the biofilm on the combined packing layer; the ecological filter further purifies the water quality through the action of multiple layers of filter media and plants; the ultraviolet disinfection device kills germs to ensure that the effluent water quality meets the standards. This system design improves the removal efficiency of pollutants, ensures the stable operation of the system, and can effectively protect the natural water body environment.

[0026] Specifically, the grid interception device can be set at a position 1.5 - 2.0 meters downstream of the road rainwater collection port. The inclination angle of the inclined grid can be selected from 60 - 75 degrees, the grid bar gap can be set to 10 - 15 mm, and the material can be selected as 304 stainless steel. The volume of the sedimentation tank can be designed to be 0.3 - 0.5 cubic meters. The bottom sludge discharge pipe can be selected as a DN150 HDPE pipe, and the end of the sludge discharge pipe can be connected to the feed port of the sludge treatment equipment. The sludge treatment equipment can be selected as a spiral sludge dewatering machine. During assembly, the inlet of the grid interception device should be flange-connected to the outlet pipe of the rainwater collection port, and the bottom slope of the sedimentation tank should be set to 3% - 5%. During the working process, when the rainwater runoff passes through the inclined grid, suspended solids with a particle size greater than 15 mm are intercepted, and fine particles precipitate in the sedimentation tank. After the sludge in the sedimentation tank reaches the set liquid level, it is discharged through the sludge discharge pipe. The grid interception device can effectively intercept large particle pollutants and realize automatic sludge cleaning.

[0027] The water inlet of the biofilm reaction tank can be set at a distance of 0.8 - 1.0 meters from the bottom of the tank body on the side wall of the tank body, and the effective water depth of the tank body can be designed to be 1.8 - 2.0 meters. The thickness of the volcanic rock packing layer can be selected as 0.5 - 0.6 meters, the thickness of the ceramsite packing layer is 0.4 - 0.5 meters, and the thickness of the polyurethane biological carrier layer is 0.3 - 0.4 meters. The aeration system can select a vortex aerator, the diameter of the aeration disc is 200 mm, the aperture of the aeration hole is 2 mm, and the main aeration pipe can be made of UPVC material. During assembly, the bottom of the combined packing layer should be 0.3 - 0.4 meters away from the bottom of the tank, and the aeration pipe network should be evenly arranged below the combined packing layer. During the working process, when the sewage passes through the combined packing layer, the biofilm removes organic matter through adsorption and degradation, and the aeration system provides dissolved oxygen and forms hydraulic disturbance. The biofilm reaction tank can enhance the microbial metabolic activity and improve the organic matter degradation efficiency.

[0028] For the ecological filter, the gravel layer can select limestone gravel with a particle size of 25 - 30 mm, and the zeolite layer can select clinoptilolite with a particle size of 6 - 8 mm. The humus for the humus planting layer can be taken from the compost products of garden waste, and the plant spacing of reeds, calamus, and iris can be set at 0.3 - 0.5 meters. The perforated collecting pipe can select an HDPE multi-hole pipe with an opening diameter of 8 mm, and is wrapped with a geotextile filter layer. During assembly, the bottom of the gravel layer should be 0.2 - 0.3 meters away from the bottom of the tank, and the center line of the perforated collecting pipe should be 0.1 - 0.15 meters higher than the bottom of the tank. During the working process, after the sewage is filtered and adsorbed through the gravel layer, etc., the plant roots absorb nitrogen and phosphorus pollutants, and the collecting pipe collects the purified water and discharges it. The ecological filter can achieve the deep removal of pollutants and the ecological restoration function.

[0029] The ultraviolet disinfection device can select a low-pressure high-intensity mercury lamp tube, the power of the lamp tube can be set at 80 - 100 W / branch, and the number of lamp tubes is configured according to the treatment volume, with 4 - 6 branches set for every 100 m³ / h. The device housing can be made of 316L stainless steel, and the width of the water flow channel is designed to be 0.3 - 0.4 meters. During assembly, the ultraviolet disinfection device should be set at the end of the effluent channel of the ecological filter, and the inlet of the device is connected to the outlet of the perforated collecting pipe through a flange. During the working process, the purified water passes through the disinfection cavity at a flow rate of 0.3 - 0.5 m / s, and the ultraviolet dose is controlled at 30 - 40 mJ / cm². The ultraviolet disinfection device can effectively inactivate pathogenic microorganisms in the water body.

[0030] In another technical solution, a transition buffer layer 24 is provided between the volcanic rock packing layer and the ceramsite packing layer of the combined packing layer. The transition buffer layer 24 is composed of zeolite particles with a particle size of 8 - 10 mm and a calcium ion exchange capacity ≥ 200 mg / g, and the thickness is 50 - 80 mm; The polyurethane biological carrier layer is provided with through microporous channels with a diameter of 1 - 1.5 mm. The inner wall of the microporous channels is coated with a nano-titanium dioxide photocatalytic coating with a thickness of 10 - 20 μm. The thickness of the polyurethane biological carrier layer is 0.4 - 0.6 m, and the porosity of its microporous channels is ≥85%, and the wet compression resilience rate is ≥90%. The aeration pipe 25 of the aeration system forms a swirling aeration structure at the bottom of the combined packing layer, and the inclination angle of the aeration holes of the aeration system is 30 - 45 degrees.

[0031] In the above technical solution, the setting of the transition buffer layer makes the water flow transition between different packings in the combined packing layer more stable, avoids the problem of uneven packing distribution caused by water flow impact, and improves the treatment effect. The microporous channels and nano-titanium dioxide photocatalytic coating of the polyurethane biological carrier layer increase the biological attachment area and photocatalytic reaction, which is beneficial to the growth of microorganisms and the degradation of pollutants. The swirling aeration structure and inclined aeration holes improve the aeration efficiency, make the dissolved oxygen evenly distributed, promote the growth and metabolism of the biofilm, and further enhance the pollutant removal ability.

[0032] Specifically, the particle size of the zeolite particles in the transition buffer layer can be selected in the range of 9 - 10 mm, and the calcium ion exchange capacity can be selected in the specification of 220 - 250 mg / g. The material can be clinoptilolite or mordenite, and the thickness can be set to 60 - 70 mm. This transition buffer layer can be assembled between the volcanic rock packing layer and the ceramsite packing layer, and the interlayer gap can be controlled at 5 - 8 mm. During the working process, when the water flow passes through the junction of packings with different particle sizes, the transition buffer layer adsorbs ammonium nitrogen through calcium ion exchange and buffers the water flow velocity to prevent the packings from moving between layers. A biofilm can be formed on the surface of the zeolite particles in the transition buffer layer, forming a synergistic treatment effect with the upper and lower packing layers and enhancing the denitrification performance.

[0033] The polyurethane biological carrier can be selected with a through microporous structure with a pore diameter of 1.2 - 1.4 mm, and the inner wall of the microporous channels can be coated with a nano-titanium dioxide coating with a thickness of 15 μm. The thickness of the carrier layer can be selected in the range of 0.45 - 0.55 m, and the porosity can be controlled in the range of 87 - 89%. The material can be hydrophilic polyurethane foam, and the wet compression resilience rate can be selected in the specification of 92 - 95%. During assembly, a space of 0.2 - 0.3 m can be maintained between the top of the polyurethane biological carrier and the water surface. During the working process, the microporous channels form turbulence to enhance the mass transfer efficiency, and the nano-titanium dioxide coating generates hydroxyl radicals under visible light to strengthen the oxidation and decomposition of organic matter. The elastic characteristics of the polyurethane material can avoid structural collapse during long-term operation.

[0034] The aeration system is optimized. The aeration pipe can be made of DN50 UPVC material pipe, the aeration hole can be set at an inclination angle of 35-40 degrees, and the aperture can be 2.5-3.0 mm. The swirl aeration structure can be designed as a ring layout, and the spacing between aeration branches can be set to 200-220 mm. During assembly, the center line of the aeration pipe can be 150-180 mm away from the bottom of the packing layer. During operation, the inclined aeration holes produce swirl water flow, and the air-water mixture rises along the spiral trajectory, extending the bubble residence time to 8-12 seconds. This structure can improve the uniformity of dissolved oxygen distribution, and the oxygen transfer efficiency per unit energy consumption can reach 6.5-7.2kgO 2 / kWh.

[0035] The transition buffer layer can smooth the shear force of the water flow and enhance the denitrification capacity. The polyurethane carrier layer can improve the removal effect of organic matter through physical structure and photocatalysis. The cyclone aeration structure optimizes the oxygen mass transfer efficiency. The combination of the three can improve the stability of system operation, reduce the risk of filler clogging, and adapt to water quality fluctuations.

[0036] In another technical solution, the humus soil planting layer includes the following components compounded in mass ratio: 60%-70% humus soil, with an organic matter content of ≥25% and a pH of 6.0-7.5; 15%-20% modified biochar particles, particle size 2-4mm, specific surface area ≥500m² / g, surface loading mass fraction of 3%-5% Fe-Mn oxide; 10%-15% diatomite-zeolite composite particles, particle size 1-3mm, calcium ion exchange capacity ≥180mg / g; 5%-8% slow-release microbial agent particles, including nitrifying bacteria, denitrifying bacteria and plant rhizosphere growth-promoting bacteria, with a content of ≥1×10 6 CFU / g, ≥5×10 5 CFU / g, ≥2×10 6 CFU / g; The humus planting layer is divided into a surface layer and a bottom layer from top to bottom, the surface layer is 50-80 mm thick, the surface layer includes humus and modified biochar mixed in a mass ratio of 7:3, and reeds, calamus and irises are planted, and the three plants are distributed at a quantity ratio of 2:1:1. A spiral guide groove is set in the root zone, the spiral guide groove is 20-30 mm deep, and the groove spacing is 80-100 mm; The bottom layer is 150-220mm thick and includes humus and diatomaceous earth-zeolite composite particles mixed in a mass ratio of 6:4. Permeable expanded clay pipes with an aperture of 10-15mm are embedded inside. The horizontal spacing of the permeable expanded clay pipes is 200-250mm and the vertical spacing is 100-150mm.

[0037] In the above technical solution, the compound composition and layered structure of the humus soil planting layer give full play to the synergistic effects of plants, microorganisms, and filter media. The modified biochar particles, diatomite-zeolite composite particles, and slow-release microbial agent particles provide a good environment for plant growth and microbial metabolism, improving the adsorption and degradation capabilities of pollutants. The spiral flow guiding grooves on the surface layer are conducive to water infiltration and the growth of plant roots, and the permeable ceramsite pipes at the bottom layer ensure the uniform distribution of water and smooth drainage, thus enhancing the purification effect of the ecological filter.

[0038] Specifically, for the material ratio of the humus soil planting layer: The humus soil can be selected as garden humus soil with an organic matter content of 28%-30%, and the pH value can be controlled between 6.5-7.0. The modified biochar particles can be selected as coconut shell carbon-based materials, and the mass fraction of the surface-loaded Fe-Mn oxides can be set at 3.8%-4.2%, and the specific surface area can be selected in the range of 550-600 m² / g. The diatomite-zeolite composite particles can be selected as prefabricated particles mixed and granulated in a mass ratio of 1:1, and the calcium ion exchange capacity can be selected as 190-200 mg / g. The slow-release bacterium agent particles can be selected as commercially available slow-release microbial preparations with an encapsulated nitrifying bacterium content of ≥1.2×10 6 CFU / g and a denitrifying bacterium content of ≥6×10 5 CFU / g. When the components are mixed in a mixer according to the mass ratio, the mixing time can be set at 15-20 minutes, and the mixing rotation speed can be selected as 30-40 rpm. During material assembly, the surface layer mixture is covered above the bottom layer mixture, and a fine sand transition layer with a thickness of 10-15 mm is set between the two.

[0039] Surface plant configuration and flow guiding structure: The plants of Phragmites australis, Acorus calamus, and Iris tectorum can be planted at intervals of 60-80 cm in a ratio of 2:1:1. The flow guiding groove can be designed as a spiral line shape, with a groove depth of 25 mm, a groove width of 15 mm, and the distance between adjacent spiral lines can be controlled at 90 mm. The spiral flow guiding groove extends outward in a clockwise or counterclockwise direction centered on the plant roots, forming a single spiral or multi-spiral path. The starting point of the flow guiding groove is within the range of 50-80 mm around the plant roots, and the spiral extension angle is 120-150 degrees. The flow guiding groove guides the water flow to form a vortex flow in the root zone, extending the hydraulic retention time to 8-10 minutes. The plant roots grow downward along the flow guiding groove, and the groove body structure can prevent the surface soil from hardening and at the same time enhance the contact efficiency between the roots and pollutants. The flow guiding groove mold can be selected as a 3D-printed ABS material template, which is pressed into the surface layer of the planting layer during construction to form a groove structure. During assembly, the starting point of the flow guiding groove is within the range of 50 mm around the plant roots, and the spiral extension angle can be set at 120-150 degrees. When the plant roots grow downward along the flow guiding groove, the groove body structure can guide the water flow to form a vortex flow in the root zone, extending the hydraulic retention time to 8-10 minutes and at the same time preventing the surface soil from hardening.

[0040] Layout of the bottom permeable ceramsite pipes: Porous ceramic pipes with an outer diameter of 12 mm and a wall thickness of 3 mm can be selected for the permeable ceramsite pipes, and the porosity can be set at 20%-25%. The center spacing of the horizontally arranged ceramsite pipes can be set at 220-230 mm, and the layer spacing in the vertical direction can be selected at 120-130 mm. The ceramsite pipes can be prefabricated into standard pipe sections with a length of 800-1000 mm, and a 5-mm expansion joint can be reserved at the pipe section connection. During assembly, the bottom mixture is filled in layers, and one layer of ceramsite pipes is placed after every 50-mm thickness of paving. The longitudinal slope of the pipe body can be set at a slope of 2%-3%. The permeable ceramsite pipes and the upper diversion trough form a three-dimensional diversion network. When the hydraulic load reaches 1.2 m³ / (m²·h), the system permeability coefficient can be maintained in the range of 0.8-1.2 cm / s.

[0041] The humus soil component removes pollutants through the synergy of physical adsorption and biodegradation. The surface diversion structure enhances the contact efficiency between the plant roots and the pollutants, and the bottom water pipe network ensures the system's permeability performance. The cooperation of the three can achieve the long-term stable operation of the planting layer, effectively improve the nitrogen and phosphorus removal ability, and prevent the problem of clogging of the filler layer at the same time.

[0042] In another technical solution, a volcanic rock particle filter layer with a particle size of 3-5 mm is wrapped around the perforated water collecting pipe. The thickness of the volcanic rock particle filter layer is 80-100 mm, and the porosity of the volcanic rock particles is 45%-55%. The perforated water collecting pipe is divided into upper and lower layers. The opening direction of the upper perforated water collecting pipe is upward and the porosity is 15%-18%. The opening direction of the lower perforated water collecting pipe is downward and the porosity is 12%-15%. The distance between the upper and lower perforated water collecting pipes is 200-250 mm.

[0043] In the above technical solution, the volcanic rock particle filter layer plays a role in protecting and filtering the perforated water collecting pipe, preventing impurities from clogging the water collecting pipe and improving the water collection efficiency. The design of the different opening directions and porosities of the upper and lower layers of perforated water collecting pipes can collect the purified water in the ecological filter more comprehensively, make the water collection more uniform, and further improve the water purification effect.

[0044] Specifically, the configuration of the volcanic rock particle filter layer: For the volcanic rock particles, basalt gravel with a particle size of 4-5 mm can be selected, and the porosity can be controlled within the range of 48%-52%. The thickness of the volcanic rock particle filter layer can be set to 85-90 mm. When constructing the wrapping layer, a geotextile-sewn bag structure is adopted, and the bag body can be made of polyester filament geotextile with a weight of 200 g / m². During assembly, the volcanic rock filter layer is closely attached to the outer wall of the perforated collector pipe, and a gap of 50-80 mm is maintained between the outer edge of the volcanic rock particle filter layer and the side wall of the ecological filter tank. During the working process, when the purified water flows through the zeolite layer and infiltrates downward, the volcanic rock particle filter layer can intercept suspended solids with a particle size > 0.5 mm, and at the same time degrade dissolved organic matter through the surface biofilm. The pore structure of the volcanic rock particle filter layer can keep the water flow velocity stable at 0.6-0.8 m / h, and still maintain more than 85% of the initial permeability coefficient after 90 days of operation.

[0045] Double-layer perforated collector pipe structure: For the upper-layer perforated collector pipe, HDPE multi-hole pipe with an opening diameter of 6 mm can be selected, the opening rate can be set to 16%-17%, the hole positions can be arranged in a plum blossom shape, and the longitudinal hole spacing can be set to 40-45 mm. For the lower-layer perforated collector pipe, UPVC multi-hole pipe with an opening diameter of 5 mm can be selected, the opening rate can be set to 13%-14%, the hole positions are arranged in a straight line, and the longitudinal hole spacing can be set to 50-55 mm. The distance between the upper and lower layers of pipes can be controlled to be 220-230 mm, and a space of 100-120 mm is maintained between the bottom of the lower-layer perforated collector pipe and the bottom of the pool. During assembly, the center line of the openings of the upper-layer perforated collector pipe forms a 15-degree upward angle with the horizontal plane, and the center line of the openings of the lower-layer perforated collector pipe forms a 20-degree downward angle with the horizontal plane. During the working process, the upper-layer perforated collector pipe mainly collects the clean water flow filtered by the upper-layer filter material (such as the zeolite layer), and the lower-layer perforated collector pipe synchronously discharges the fine particles deposited in the gravel layer. When the instantaneous flow rate of the system reaches 1.5 times the design value, the double-layer structure can reduce the water level fluctuation amplitude to within ±50 mm.

[0046] Effect of the stratified opening direction on anti-blocking and water collection uniformity: Upper-layer perforated collector pipe, anti-blocking: Through the design of upward openings, it preferentially collects the clean water flow filtered by the upper-layer filter material (such as the zeolite layer), avoiding sucking in the suspended particles or sediments that may accumulate at the bottom, thereby reducing the risk of the holes being blocked.

[0047] Water collection uniformity: The upward-angle openings prompt the water flow to enter the collector pipe along a gentle path, reducing the sudden change in local flow velocity, which helps to achieve uniform water collection on the water surface and avoid regional overload or turbulence caused by concentrated water flow.

[0048] Lower-layer perforated collector pipe, anti-blocking: The downward openings can actively discharge the fine particles deposited in the bottom filter material (such as the gravel layer), guiding the impurities away from the collector pipe area through the action of gravity, and preventing the holes from being blocked due to long-term siltation.

[0049] Water collection uniformity: The downward-opening holes promote the gentle upward flow of water at the bottom to the water collection pipe, reducing the phenomenon of direct water impact or "short circuit", and ensuring the balanced distribution of water flow in each area of the filter tank section.

[0050] Cooperation between the upper perforated water collection pipe and the lower perforated water collection pipe: The opening directions of the upper and lower layers are complementary. The upper layer focuses on the collection of clean water flow, and the lower layer is responsible for the dynamic cleaning of sediments. The combination of the two forms a gradient sewage interception mechanism. Through the layered design, the system can adapt to different flow conditions, maintain a stable water collection efficiency under high-load conditions, and at the same time reduce the attenuation of the permeability of the filter media layer caused by local blockage. This solution optimizes the physical structure, taking into account the requirements of anti-blockage and water collection uniformity, and can improve the long-term operation reliability of the system without relying on complex control.

[0051] The volcanic rock filter layer effectively prevents the blockage of the holes in the perforated water collection pipe, and the double-layer perforated pipe structure realizes the functions of hierarchical water collection and silt discharge. The cooperation of the two can improve the operation stability of the ecological filter tank, maintain a stable effluent quality under high hydraulic load conditions during the rainstorm period, and at the same time extend the filter tank maintenance and cleaning cycle to 12 - 18 months.

[0052] In another technical solution, it further includes a backwashing system, which includes a municipal water supply pipe and an ultraviolet disinfection return water pipe connected by a three-way valve. The backwashing water is reversely injected into the perforated water collection pipe through the backwashing branch pipe. The end of the backwashing branch pipe is connected to a sludge collection tank 35, and the bottom of the sludge collection tank 35 is connected to a sludge treatment device through a screw conveyor; The end of the perforated water collection pipe is connected to the backwashing branch pipe, and a pressure sensor is provided on the backwashing branch pipe. When the pressure difference inside and outside the water collection pipe is detected to exceed the set threshold, the backwashing mode is triggered.

[0053] In the above technical solution, the setting of the backwashing system solves the problem of blockage of the water collection pipe and the filter media layer, and ensures the long-term stable operation of the system. When the pressure sensor detects that the pressure difference inside and outside the water collection pipe exceeds the threshold, the backwashing mode is automatically triggered, and the backwashing is carried out using the municipal water supply or the ultraviolet disinfection return water. The sludge is flushed into the sludge collection tank and then transported to the sludge treatment device through the screw conveyor, realizing the timely treatment of the sludge and the automatic operation of the system.

[0054] Specifically, the backwashing system pipeline configuration: The three-way valve can be selected as a DN100 pneumatic butterfly valve type switching device, and the valve body material can be selected as brass with nickel plating treatment. The backwashing branch pipe can be selected as a DN80 HDPE pipe, and the working pressure can be set to 0.4 - 0.6 MPa. The sludge collection tank can be selected as a PE material tank with a volume of 2 - 3 cubic meters. The screw conveyor can be selected as a shaftless screw conveyor with a diameter of 300 mm, and the conveying speed can be adjusted to 2 - 3 m / min. During assembly, the three-way valve can be installed at the inlet end of the backwashing branch pipe, 1.2 - 1.5 meters away from the nearest perforated water collecting pipe interface. During operation, when switched to the backwashing mode, the pressurized water rushes into the water collecting pipe reversely at a flow rate of 1.2 - 1.5 m / s, and the washing intensity can be controlled at 12 - 15 L / (m²·h). After 8 - 10 minutes, it is switched back to the normal operation mode.

[0055] Differential pressure trigger control logic: The pressure sensor can be selected as a piezoresistive sensor with a measuring range of 0 - 100 kPa, and the installation position can be set 0.5 - 0.8 meters away from the end of the backwashing branch pipe. The differential pressure threshold can be set to 20 kPa. When it is detected that the differential pressure inside and outside the water collecting pipe exceeds this value and lasts for 120 seconds, the PLC controller can start the backwashing program. During assembly, the pressure sensor probe can be embedded into 1 / 2 of the pipe wall thickness, and the signal wire is connected to the control cabinet through a waterproof joint. During operation, when the filter media layer is blocked, resulting in an increase in water flow resistance, the backwashing system automatically switches the water source for backwashing. After the sludge carried by the backwashing water flow enters the collection tank, it is transported to the dewatering equipment by the screw conveyor at a rotation speed of 45 - 50 rpm. The drainage volume for each backwashing can be controlled at 3% - 5% of the total water volume of the system.

[0056] The backwashing pipeline configuration realizes the reverse cleaning function of the system, and the differential pressure trigger mechanism ensures timely removal of the blockage in the packing layer. The two cooperate to maintain the stable permeability of the ecological filter pool, reduce the frequency of manual maintenance, and effectively prevent the system efficiency decay caused by excessive accumulation of biofilm during long-term operation.

[0057] In another technical solution, a turbidity sensor and a flow meter are provided at the water inlet of the ultraviolet disinfection device. When the turbidity > 5 NTU or the flow rate exceeds 20% of the design value, the PLC controller synchronously controls the lamp power of the ultraviolet disinfection device to be increased to 100% - 110% for operation, and the over-power operation does not exceed 30 minutes each time; An ultraviolet intensity monitoring probe is provided at the end of the ultraviolet disinfection device. When the detected dose < 30 mJ / cm², the water flow residence time is extended to 1.2 - 1.5 times the original value.

[0058] In the above technical solution, the ultraviolet disinfection device automatically adjusts the lamp power and the water flow residence time according to the changes in turbidity and flow rate, which can ensure good disinfection effects under different water quality and flow rate conditions, and avoid the problems of incomplete disinfection or energy waste. When the turbidity is high or the flow rate is large, the lamp power is increased; when the ultraviolet intensity is insufficient, the water flow residence time is extended, ensuring the hygienic safety of the effluent.

[0059] Specifically, for the dynamic adjustment mechanism of ultraviolet power: The turbidity sensor can select an online scattering light turbidimeter with a measuring range of 0 - 20 NTU, and the installation position can be set at the straight pipe section 0.8 - 1.2 meters upstream of the inlet of the ultraviolet disinfection device. The flowmeter can select a DN150 electromagnetic flowmeter, and the measurement accuracy can be controlled within ±1.5% FS. The PLC controller can be built-in with a two-stage control strategy: When it is detected that the turbidity > 5 NTU or the instantaneous flow rate exceeds 20% of the design value (for example, when the design flow rate is 100 m³ / h, the trigger threshold is 120 m³ / h), the ultraviolet lamp power can be increased to 105% - 108% of the rated power, and the duration of over-power operation can be set to 25 - 28 minutes. During assembly, the turbidity sensor probe can be inserted into the position at 1 / 3 depth below the center line of the pipeline, and the lengths of the straight pipe sections before and after the flowmeter can meet the requirements of 10D in the front and 5D in the back (D is the pipe diameter). During the working process, when the water quality deteriorates or the water volume suddenly increases, the ultraviolet disinfection device automatically increases the ultraviolet intensity to 30 - 35 mJ / cm² to ensure stable disinfection effects.

[0060] Ultraviolet dose compensation control: The ultraviolet intensity monitoring probe can select an ultraviolet photosensitive sensor with a wavelength of 254 nm, and the measuring range can be set to 0 - 50 mJ / cm². The probe can be installed outside the quartz sleeve at the outlet end of the ultraviolet disinfection device, 150 - 180 mm away from the last row of lamps. When it is detected that the actual dose < 30 mJ / cm², the PLC can control the opening degree of the outlet electric valve to decrease from fully open to 75% - 80%, so that the water flow residence time is extended from the reference value of 8 seconds to 9.6 - 10 seconds. During assembly, the protective cover of the ultraviolet intensity monitoring probe can be made of quartz glass, and the light transmittance can be maintained above 90%. During the working process, when the lamps age or the light transmittance of the water body decreases, the contact time is extended to compensate for the disinfection dose, and the water flow velocity during the compensation stage can be reduced to 0.25 - 0.3 m / s to ensure that the cumulative ultraviolet dose maintains an effective disinfection level.

[0061] The power adjustment mechanism can cope with the changes in disinfection requirements brought about by fluctuations in the influent water quality, and the dose compensation control ensures the continuous disinfection efficiency of the ultraviolet system. The two work together to adapt to the high-turbidity sewage in the rainy season and the working conditions of equipment performance attenuation without increasing the equipment capacity, and effectively maintain the compliance discharge of water body microbial indicators.

[0062] In another technical solution, an ultrasonic liquid level sensor is provided on the side wall of the sedimentation tank. The height of the probe of the ultrasonic liquid level sensor from the bottom of the sedimentation tank is 2 / 3 - 3 / 4 of the depth of the sedimentation tank, and it is detected according to the set detection frequency. A pneumatic knife gate valve with a gate plate thickness of 8 - 10 mm is provided at the inlet of the sludge discharge pipe. The ultrasonic liquid level sensor is connected to the PLC controller. When the sludge layer height is detected to be > 1 / 2 of the depth of the sedimentation tank for 3 consecutive times, the PLC controller controls the pneumatic knife gate valve to fully open within 15 seconds, and discharges sludge until the ultrasonic liquid level sensor detects that the sludge layer height is less than the set low-level threshold, then the pneumatic knife gate valve closes. The outlet of the sludge discharge pipe is connected to the inlet of the screw conveyor, and the outlet of the screw conveyor is connected to the receiving bin of the sludge treatment equipment.

[0063] In the above technical solution, through the cooperation of the ultrasonic liquid level sensor and the PLC controller, the automatic control of the sludge discharge in the sedimentation tank is realized. When the sludge layer height exceeds the set value, the pneumatic knife gate valve automatically opens for sludge discharge, and automatically closes after discharging to the low-level threshold, ensuring the normal operation of the grid interception device, avoiding the influence of sludge accumulation on the system, and improving the efficiency of sludge treatment at the same time.

[0064] Specifically, the installation and monitoring logic of the ultrasonic liquid level sensor can be set at a height of 0.9 - 1.1 meters from the bottom of the sedimentation tank side wall. This position corresponds to the range of two-thirds to three-fourths of the total depth of the sedimentation tank. The ultrasonic liquid level sensor can select a pulsed ultrasonic probe with a measuring range of 0 - 2 meters, and the detection frequency can be set to one cycle per 10 minutes. The probe protective cover of the ultrasonic liquid level sensor can select PTFE material, and its acid and alkali resistance meets the environmental requirements of pH 3 - 11. During assembly, the flange of the ultrasonic liquid level sensor and the opening of the tank wall are fixed with four bolts, and the sealing gasket can select ethylene propylene diene monomer rubber material. During the working process, when the sludge layer interface height is detected to exceed 0.6 meters three consecutive times, the system determines it as the high-level alarm state and triggers the sludge discharge program.

[0065] The pneumatic knife gate valve can select a 304 stainless steel valve body with a nominal diameter of 150 mm, the gate plate thickness can select a 9 mm specification, and the actuator can be configured with a direct stroke cylinder with a stroke time of 15 seconds. The sludge discharge pipe can select a DN150 ultra-high molecular weight polyethylene pipe, and the screw conveyor can select a horizontal shaftless model with a power of 5.5 kW. During assembly, the knife gate valve can be installed at the starting end of the sludge discharge pipe, 0.3 - 0.5 meters away from the bottom outlet of the sedimentation tank, and the valve body axis is inclined downward at an angle of 3 - 5 degrees with the horizontal plane. During the working process, when the PLC controller issues a sludge discharge instruction, the cylinder completes the fully open action within 12 - 15 seconds, and the sludge enters the conveyor at a flow rate of 0.8 - 1.2 m / s until the liquid level drops to the 0.3-meter threshold and then the valve closes.

[0066] The PLC controller of the sludge treatment linkage control system can be built-in with two-stage delay protection, and automatically cut off the air source when the cumulative time of sludge discharge operation exceeds 30 minutes. The rotation speed of the screw conveyor can be set at 40 - 45 rpm, and the conveying capacity matches the sludge discharge flow rate of 10 - 12 m³ / h. During assembly, the feed inlet of the conveyor and the outlet of the sludge discharge pipe are flexibly connected, and a 50 mm height difference is reserved to form material self-flow. During the working process, the sludge is extruded and dehydrated by the conveyor to form a mud cake with a moisture content of 75 - 80%, which falls into the sludge collection box through the chute, and the treatment cycle is synchronized with the sedimentation tank dredging requirement.

[0067] The liquid level monitoring system realizes the precise perception of the sludge deposition state, and the linkage control of the pneumatic valve and the conveying equipment ensures timely dredging. This configuration can reduce the frequency of manual inspections, avoid the risk of system blockage caused by excessive siltation in the sedimentation tank, and at the same time ensure the production capacity matching of the sludge discharge operation and the backend treatment equipment.

[0068] In another technical solution, three dissolved oxygen sensors are arranged at intervals along the water flow direction in the biological membrane reaction tank, which are respectively located 200 mm above the bottom of the combined packing layer, in the middle, and 150 mm below the top. The blower of the aeration system is equipped with a variable frequency controller with an output frequency of 30 - 50 Hz, and the variable frequency controller is connected to the PLC controller through a 4 - 20 mA signal. The PLC controller is built-in with a segmented control algorithm. When the values of any two dissolved oxygen sensors < 2.5 mg / L, the frequency of the blower is controlled to rise to 40 - 45 Hz. When the values of all three dissolved oxygen sensors > 3.0 mg / L, the frequency is reduced to 35 - 38 Hz. The air outlet pipe of the blower is provided with a bypass pressure relief branch pipe with a solenoid valve. When the aeration intensity > 1.2 m³ / (m²·h) lasts for 5 minutes, the solenoid valve opens at a 10% - 15% opening degree.

[0069] In the above technical solution, the dissolved oxygen sensors in the biological membrane reaction tank, the variable frequency controller of the aeration system, and the segmented control algorithm of the PLC controller can accurately control the dissolved oxygen concentration. According to the real-time data of the dissolved oxygen sensors, the frequency of the blower is automatically adjusted to keep the dissolved oxygen concentration within the range suitable for the growth of biological membranes and the degradation of pollutants. The setting of the bypass pressure relief branch pipe ensures the safe operation of the aeration system and avoids the damage to the system caused by excessive aeration intensity.

[0070] Specifically, the arrangement of the dissolved oxygen sensor can be set at heights of 0.8 m, 1.2 m, and 1.7 m from the bottom of the side wall of the biofilm reaction tank, corresponding to positions 200 mm above the bottom of the combined packing layer, in the middle, and 150 mm below the top. The dissolved oxygen sensor can select a fluorescence dissolved oxygen probe with a measuring range of 0 - 10 mg / L, and the protection level can reach the IP68 standard. During assembly, the front end of the dissolved oxygen sensor probe can be 50 - 80 mm away from the inner side of the pool wall, and the axis of the probe forms a 15-degree upward angle with the horizontal plane to avoid direct impact of bubbles. During the working process, the three dissolved oxygen sensor probes respectively monitor the dissolved oxygen concentrations at different depths. When the value of the bottom sensor is lower than 2.5 mg / L, the aeration enhancement mode is triggered.

[0071] The variable frequency controller can select a vector frequency converter with a 4 - 20 mA signal input, and the output frequency adjustment range can be set to 30 - 50 Hz. The blower can select a Roots blower, and the rated air volume can match the 4.5 m³ / min specification. During assembly, the frequency converter can be installed in the control cabinet 3 - 5 m away from the blower, and the power cable can select a 3-core 4 mm² copper core shielded cable. During the working process, when the values of any two dissolved oxygen sensors are continuously lower than the 2.5 mg / L threshold for 60 seconds, the PLC outputs a signal to increase the frequency of the frequency converter from the reference value of 35 Hz to 42 Hz, and the aeration volume is increased from 0.9 m³ / (m²·h) to 1.1 m³ / (m²·h), and the oxygen transfer efficiency is increased to 7.2 kgO2 / kWh.

[0072] The bypass pressure relief branch pipe can select a DN80 UPVC pipe, and the solenoid valve can select a normally closed pilot solenoid valve with a nominal diameter of 50 mm. The end of the pressure relief branch pipe can be connected to a silencer, and the silencer can select a honeycomb structure made of fiberglass. During assembly, the branch pipe interface can be set 1.2 - 1.5 m above the top of the blower outlet pipe, and the actuator of the solenoid valve can be installed vertically upward. During the working process, when the aeration intensity exceeds 1.2 m³ / (m²·h) and lasts for 300 seconds, the solenoid valve opens at a 12% opening for pressure relief, and the system pressure drops from 65 kPa to 58 kPa to prevent the fan from overloading.

[0073] Multi-point dissolved oxygen monitoring realizes three-dimensional oxygen concentration control in the reaction tank, and the coordinated action of variable frequency regulation and pressure relief protection ensures the safe and economical operation of the aeration system. This configuration can quickly respond to changes in dissolved oxygen demand during water quality fluctuations, avoid a decrease in the activity of the biofilm caused by hypoxia or over-aeration, and at the same time reduce the equipment failure rate.

[0074] <Test> 1. Test Purpose Test the adaptability of Phragmites australis, Acorus calamus and Iris pseudacorus in a simulated ecological filter environment, and obtain the survival rate and growth status data for 6 consecutive months.

[0075] 2. Test materials Plant samples: Select healthy 1-year-old seedlings without pests and diseases, with the plant height of Phragmites australis being 40±5 cm, the crown width of Acorus calamus being 25±3 cm, and the number of leaves of Iris pseudacorus being ≥4; Planting substrate: Prepare a humus soil planting layer according to the ratio (humus soil 65% + modified biochar 18% + diatomite-zeolite composite particles 14% + slow-release bactericide 3%) Control substrate: Ordinary garden soil (pH 7.1, organic matter content 8%) 3. Test devices Construct 6 groups of simulated ecological filters with dimensions of 1.2 m×0.6 m×0.8 m: Filter layer structure: The bottom layer is 30 cm of gravel (particle size 25-30 mm), the middle layer is 20 cm of zeolite (particle size 6-8 mm), and the top layer is 25 cm of test / control substrate; Hydraulic system: Perforated water distribution pipe (flow rate 0.8 m³ / d), collecting pipe, circulation pump; Environmental control: Natural light + supplementary light (light intensity 8000-10000 lux, 12 h per day), temperature maintained at 18-28°C; 4. Test methods Planting arrangement: Plant in each pool according to a ratio of 2:1:1 (8 Phragmites australis + 4 Acorus calamus + 4 Iris pseudacorus), with a plant spacing of 40 cm; Water level control: Maintain a flooding depth of 5-8 cm below the substrate surface; Nutrient supply: Inject simulated runoff water every week (COD 80-120 mg / L, NH3-N 8-12 mg / L, TP 1.5-2.0 mg / L) Data collection: Monthly detection: Number of surviving plants, growth rate of plant height / crown width, root length; Every two months detection: Chlorophyll content (SPAD value), root activity (TTC method); Environmental monitoring: Water temperature, pH, dissolved oxygen (recorded daily); 5. Data analysis Survival rate calculation: Number of surviving plants / Initial number of plants × 100% Growth index: ΔH = (Final plant height - Initial plant height) / Initial plant height × 100% Significance test: One-way ANOVA was performed using SPSS 26 (α = 0.05) 6. Key test results Table 1 Key test data Note: The data of the control group showed that the survival rate, growth rate and physiological indexes of plants in ordinary garden soil were significantly lower than those of the experimental group (P<0.05), further verifying the superiority of the humus soil planting layer ratio.

[0076] 7. Summary of test results 7.1 Plant survival performance: Phragmites australis, Acorus calamus and Iris tectorum all showed high adaptability in the simulated ecological filter pond environment. During the 6-month test period, the survival rate of Phragmites australis was the highest (>90%), and the survival rates of Acorus calamus and Iris tectorum were both >85%, which were significantly better than those of the ordinary garden soil control group (survival rate <60%). The death of plants mainly concentrated in the initial stage of the experiment (the first 30 days), and the survival status tended to be stable in the later stage.

[0077] 7.2 Growth characteristic analysis: Phragmites australis: The increase in plant height was the largest (more than 2 times the initial value), and the longitudinal extension ability of the root system was prominent (average length >55 cm), showing strong water absorption and flooding resistance; Acorus calamus: The expansion rate of the crown width was the fastest (average monthly increase of 12-15 cm), and the horizontal root system was well-developed (the tiller number increased by 3-4 times), suitable for intercepting surface pollutants; Iris tectorum: The chlorophyll content was the highest (SPAD value >45), and the accumulation of root biomass was significant (the dry weight increased by 4.2 times compared with the initial), indicating its better photosynthesis and nutrient absorption efficiency.

[0078] 7.3 Environmental tolerance: All plants did not show stress symptoms such as yellow leaves and rotten roots under the simulated runoff water quality (COD≤120mg / L, NH3-N≤12mg / L); The root activity (TTC reduction intensity ≥0.8mg / g·h) remained active continuously, confirming the stability of the microorganism-plant synergistic effect; During the winter low temperature period (15-18℃), the growth rate decreased by 20%-30%, but there was no freezing injury or dormancy phenomenon.

[0079] The test shows the rationality of the humus soil planting layer ratio of this application, and the plant roots form an effective synergy with the diversion trough structure and the permeable ceramsite pipe: The deep roots of Phragmites australis enhance the water permeability of the lower substrate, the fibrous roots of Acorus calamus promote the interception of surface pollutants, and the high metabolic activity of Iris tectorum strengthens the absorption of nitrogen and phosphorus.

[0080] All three plants met the long-term survival requirements of 6 months in the simulated system. Their differential growth characteristics can adapt to the multi-level purification function of the ecological filter pond, providing a reliable biological carrier for the long-term operation of the system.

[0081] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A biological-ecological synergistic purification system for municipal road runoff pollutants, characterized in that: include: A grille interception device is arranged downstream of the road rainwater collection port, the grille interception device comprises an inclined grille, a sedimentation trough is arranged at the bottom of the inclined grille, a mud discharge pipe is connected to the bottom of the sedimentation trough, and a mud discharge pipe is connected to the end of the mud treatment equipment; A biofilm reaction tank, whose water inlet is connected to the water outlet of the grid interception device, and a combined filler layer is arranged in the biofilm reaction tank, wherein the combined filler layer is, from bottom to top, a volcanic rock filler layer with a particle size of 10-15 mm, a ceramsite filler layer with a particle size of 5-8 mm, and a polyurethane biological carrier layer with a specific surface area greater than 800 m² / m³, and the total thickness of the combined filler layer is 1.2-1.5 m. An aeration system is arranged at the bottom of the biofilm reaction tank, and the output intensity of the aeration system is 0.8-1.2 m³ / (m²·h); The ecological filter tank has a water inlet connected to the water outlet of the biofilm reaction tank. A gravel layer with a thickness of 0.5-0.8m, a zeolite layer with a thickness of 0.3-0.5m and a humus planting layer with a thickness of 0.2-0.3m are arranged from bottom to top in the ecological filter tank. The particle size of the gravel layer is 20-30mm, the particle size of the zeolite layer is 5-10mm, reeds, calamus and iris are planted in the humus planting layer, and a perforated water collection pipe with an opening rate of 15%-20% is arranged at the bottom of the ecological filter tank; The ultraviolet disinfection device is arranged at the water outlet of the ecological filter tank, and the water outlet of the ultraviolet disinfection device is connected to the natural water body discharge pipe.

2. The biological-ecological coordinated purification system according to claim 1 is characterized in that: A transition buffer layer is provided between the volcanic rock filler layer and the ceramsite filler layer of the combined filler layer, the transition buffer layer is composed of zeolite particles with a particle size of 8-10 mm and a calcium ion exchange capacity of ≥200 mg / g, and a thickness of 50-80 mm; The polyurethane bio-carrier layer is provided with a penetrating microporous channel, the diameter of the microporous channel is 1-1.5 mm, the inner wall of the microporous channel is coated with a nano titanium dioxide photocatalytic coating with a thickness of 10-20 μm, the thickness of the polyurethane bio-carrier layer is 0.4-0.6 μm, and the porosity of the microporous channel is ≥85%, and the wet compression rebound rate is ≥90%; The aeration pipe of the aeration system forms a cyclone aeration structure at the bottom of the combined filler layer, and the aeration holes of the aeration system have an inclination angle of 30-45 degrees.

3. The biological-ecological coordinated purification system according to claim 2 is characterized in that: The humus soil planting layer comprises the following components compounded in mass ratio: 60%-70% humus soil, with an organic matter content of ≥25% and a pH of 6.0-7.5; 15%-20% modified biochar particles, particle size 2-4mm, specific surface area ≥500m² / g, surface loading mass fraction of 3%-5% Fe-Mn oxide; 10%-15% diatomite-zeolite composite particles, particle size 1-3mm, calcium ion exchange capacity ≥180mg / g; 5%-8% slow-release microbial agent particles, including nitrifying bacteria, denitrifying bacteria and plant rhizosphere growth-promoting bacteria, with a content of ≥1×10 6 CFU / g, ≥5×10 5 CFU / g, ≥2×10 6 CFU / g; The humus planting layer is divided into a surface layer and a bottom layer from top to bottom, the surface layer is 50-80 mm thick, the surface layer includes humus and modified biochar mixed in a mass ratio of 7:3, and reeds, calamus and irises are planted, and the three plants are distributed at a quantity ratio of 2:1:

1. A spiral guide groove is set in the root zone, the spiral guide groove is 20-30 mm deep, and the groove spacing is 80-100 mm; The bottom layer is 150-220mm thick and includes humus and diatomaceous earth-zeolite composite particles mixed in a mass ratio of 6:

4. Permeable expanded clay pipes with an aperture of 10-15mm are embedded inside. The horizontal spacing of the permeable expanded clay pipes is 200-250mm and the vertical spacing is 100-150mm.

4. The biological-ecological coordinated purification system according to claim 2 is characterized in that: The outer periphery of the perforated water collecting pipe is wrapped with a volcanic rock particle filter layer with a particle size of 3-5 mm, the thickness of the volcanic rock particle filter layer is 80-100 mm, and the porosity of the volcanic rock particles is 45%-55%; The perforated water collecting pipe is divided into two layers, the upper perforated water collecting pipe has an opening direction facing upward and an opening rate of 15%-18%, the lower perforated water collecting pipe has an opening direction facing downward and an opening rate of 12%-15%, and the spacing between the upper and lower perforated water collecting pipes is 200-250mm.

5. The biological-ecological coordinated purification system according to claim 4 is characterized in that: It also includes a backwashing system, which includes a municipal water supply pipe and an ultraviolet disinfection return water pipe connected by a three-way valve switch, and the backwashing water is reversely injected into the perforated water collecting pipe through the backwashing branch pipe. The end of the backwashing branch pipe is connected to a sludge collection tank, and the bottom of the sludge collection tank is connected to the sludge treatment equipment through a screw conveyor; The end of the perforated water collecting pipe is connected to a backwash branch pipe, and a pressure sensor is provided on the backwash branch pipe. When it is detected that the pressure difference between the inside and outside of the water collecting pipe exceeds a set threshold, a backwash mode is triggered.

6. The biological-ecological coordinated purification system according to claim 1, characterized in that: The water inlet of the ultraviolet disinfection device is equipped with a turbidity sensor and flow meter. When the turbidity is greater than 5NTU or the flow exceeds the design value by 20%, the PLC controller synchronously controls the lamp power of the ultraviolet disinfection device to increase to 100%-110%, and the over-power operation shall not exceed 30 minutes at a time. A UV intensity monitoring probe is installed at the end of the UV disinfection device. When the detected dose is less than 30mJ / cm², the water flow residence time is extended to 1.2-1.5 times the original value.

7. The biological-ecological coordinated purification system according to claim 1, characterized in that: The side wall of the sedimentation tank is provided with an ultrasonic liquid level sensor, the height of the ultrasonic liquid level sensor probe from the bottom of the sedimentation tank is 2 / 3-3 / 4 of the depth of the sedimentation tank, and detection is performed according to the set detection frequency; The mud discharge pipe inlet is equipped with a pneumatic knife gate valve with a gate thickness of 8-10mm; The ultrasonic liquid level sensor is connected to the PLC controller. When the sludge layer height is detected to be greater than 1 / 2 of the sedimentation tank depth for three consecutive times, the PLC controller controls the pneumatic knife gate valve to fully open within 15 seconds to discharge the sludge until the ultrasonic liquid level sensor detects that the sludge layer height is less than the set low-level threshold. The pneumatic knife gate valve is closed, and the sludge discharge pipe outlet is connected to the screw conveyor feed port, and the screw conveyor discharge port is connected to the sludge treatment equipment receiving bin.

8. The biological-ecological coordinated purification system according to claim 4 is characterized in that: Three dissolved oxygen sensors are arranged in the biofilm reaction tank along the water flow direction, respectively located 200 mm above the bottom, in the middle and 150 mm below the top of the combined packing layer; The blower of the aeration system is equipped with a variable frequency controller with an output frequency of 30-50Hz, which is connected to the PLC controller via a 4-20mA signal; The PLC controller has a built-in segmented control algorithm. When the values ​​of any two dissolved oxygen sensors are less than 2.5 mg / L, the blower frequency is controlled to increase to 40-45 Hz. When the values ​​of the three dissolved oxygen sensors are all greater than 3.0 mg / L, the frequency is reduced to 35-38 Hz. The blower outlet pipe is equipped with a bypass pressure relief branch with a solenoid valve. When the aeration intensity is greater than 1.2m³ / (m²·h) for 5 minutes, the solenoid valve opens 10%-15%.

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