A deep-bed denitrification water treatment system with synergistic effect of functional filter media

Abstract

The present invention relates to the technical field of wastewater treatment, and particularly to a deep-bed denitrification water treatment system with synergistic enhancement of functional filter media, comprising: a filter tank module, a water inlet module, a filter media module, a detection module, and a treatment control module; the filter tank module provides a basic space for treating nitrogen-containing sewage; the water inlet module uniformly conveys nitrogen-containing sewage into the building tank body; the filter media module is arranged inside the filter tank module, adsorbs organic matters in the sewage and provides attachment sites for denitrifying bacteria; the collection module continuously collects nitrogen and nitrogen-free wastewater; the detection module detects the water flow direction and water flow velocity of the nitrogen-containing sewage, calculates the water flow stability characterization parameter according to the detection result, and obtains the inclination angle and the guiding hole passing rate of each modified filter layer; the treatment control module determines whether the water flow distribution of the current layer is normal, determines whether to adjust the corresponding modified filter layer, and determines whether there is an abnormality in nitrogen emission; the present invention reduces the carbon source dosage and backwashing frequency, and simultaneously improves the stability of the effluent water quality.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly to a deep-bed denitrification water treatment system with synergistic enhancement of functional filter media. Background Art

[0002] In recent years, with the full implementation of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB 18918-2002), the total nitrogen (TN) emission limit has been further tightened, and there is an urgent need for sewage treatment plants to upgrade their standards. However, existing denitrification filters have many inherent defects in technical principles, structural designs, and operation modes. Traditional filters mostly adopt the upper-inlet or side-inlet mode, with uneven water flow distribution, which is prone to form "preferential flow channels", resulting in uneven hydraulic retention time distribution, large fluctuations in TN removal efficiency, and the need to overdose carbon sources to compensate for inefficient areas, leading to a sharp increase in operating costs. In addition, the carbon source mixing mechanism is backward, and the effective utilization rate is less than 60%. A large amount of carbon source is lost without participating in denitrification, and at the same time, the excessive carbon source will also cause the increase of chemical oxygen demand COD (Chemical Oxygen Demand, the oxygen equivalent consumed by reducing inorganic substances and organic substances (generally organic substances) that need to be oxidized in the water sample measured by chemical reaction) in the effluent, triggering the risk of secondary pollution.

[0003] The density of nitrogen gas generated by the denitrification reaction is lower than that of water. When the traditional filter adopts the upper-inlet mode, nitrogen gas stays in the pores of the filter material, resulting in a sharp increase in the pressure loss of the filter and an increase in the backwashing frequency. Frequent backwashing not only increases energy consumption but also causes filter material wear and shortens the replacement cycle. In addition, conventional filter materials such as quartz sand and anthracite only serve as biological film carriers, lacking the functions of carbon source slow release or gas conduction. Under the condition of low-carbon source influent, the activity of denitrifying bacteria is inhibited due to insufficient carbon source, and the TN removal rate drops sharply. Existing slow-release carbon source materials have poor matching between the carbon release rate and denitrification requirements, and cannot meet the requirements of long-term stable operation. Traditional filter bricks only bear the functions of load-bearing and basic water distribution, the hole distribution does not consider the correction of edge effects, and there is no gas conduction channel inside, resulting in uneven water distribution and gas conduction blind areas, further exacerbating the gas blockage problem. Summary of the Invention

[0004] Therefore, the present invention provides a deep-bed denitrification water treatment system with synergistic enhancement of functional filter media to overcome the problems in the prior art that the hole distribution of filter bricks does not consider the correction of edge effects, resulting in uneven water distribution and gas conduction blind areas, and further exacerbating the gas blockage problem.

[0005] To achieve the above object, the present invention provides a deep-bed denitrification water treatment system with synergistic enhancement of functional filter media, including:

[0006] A filter tank module, which includes a building tank body and several modified filter layers, for providing a basic space for treating nitrogen-containing sewage;

[0007] An influent module, which is connected to the bottom of the filter tank module and is used to transport the nitrogen-containing sewage into the building tank body;

[0008] A filter media module, which is arranged inside the filter tank module and is located above the influent module, and is used to adsorb small molecule organic matters in the nitrogen-containing sewage and provide attachment sites for denitrifying bacteria;

[0009] A collection module, which is connected to the filter tank module and is used to continuously collect the nitrogen and nitrogen-free wastewater obtained after treating the nitrogen-containing sewage;

[0010] A detection module, which is respectively connected to the filter tank module, the influent module and the collection module, and is used to detect the water flow direction and water flow velocity of the nitrogen-containing sewage to determine the water flow stability characterization parameters, and obtain the inclination angles and pore passing rates of the modified filter layers;

[0011] A treatment control module, which is respectively connected to the filter tank module, the influent module and the detection module, and is used to determine whether the current layer of water flow is normally distributed according to the water flow stability characterization parameters, determine whether to adjust the corresponding modified filter layer according to the judgment result of normal water flow distribution combined with the inclination angles of the modified filter layers, and determine whether there is an abnormality in nitrogen emission according to the pore passing rate of the modified filter layer to determine whether to increase the number of modified filter layers.

[0012] As a preferred technical solution of the deep bed denitrification water treatment system with synergistic effect of functional filter media, the modified filter layer is composed of honeycomb diversion filter bricks covered with a nano hydrophilic coating;

[0013] Wherein, a number of spiral through holes for water flow are arranged inside the honeycomb diversion filter bricks.

[0014] As a preferred technical solution of the deep bed denitrification water treatment system with synergistic effect of functional filter media, the influent module includes:

[0015] A lower influent diversion unit, which is used to transport the nitrogen-containing sewage into the building tank body at a preset water flow velocity;

[0016] A layered water distribution unit, which is connected to the lower influent diversion unit and is used to divide the nitrogen-containing sewage into several vertically upward filtering water flows.

[0017] As a preferred technical solution of the deep bed denitrification water treatment system with synergistic effect of functional filter media, the filter media module includes functional filter media and volcanic rock activated carbon;

[0018] Wherein, the functional filter media is composed of ceramic fiber, modified zeolite and silane coupling agent.

[0019] As a preferred technical solution of the deep-bed denitrification water treatment system with synergistic effect of functional filter materials, the water flow direction and water flow velocity of the nitrogen-containing sewage detected by the detection module specifically include the first water flow direction and the first water flow velocity of each filtered water flow, and the second water flow direction and the second water flow velocity of the water flow at the outlet of each first-layer modified filter layer;

[0020] Among them, the numbers of the first water flow direction and the first water flow velocity are the same as the number of filtered water flows;

[0021] The numbers of the second water flow direction and the second water flow velocity are the same as the number of outlets of the modified filter layer.

[0022] As a preferred technical solution of the deep-bed denitrification water treatment system with synergistic effect of functional filter materials, the detection module constructs a characterization vector group of the filtered water flow according to all the first water flow directions and the corresponding first water flow velocities, and calculates the sum vector, the average deviation of the modulus length and the average value of the modulus length of the characterization vector group;

[0023] The detection module determines the water flow stability characterization parameter according to the ratio of the average deviation of the modulus length to the average value of the modulus length and the angle of the sum vector.

[0024] As a preferred technical solution of the deep-bed denitrification water treatment system with synergistic effect of functional filter materials, the detection module obtains the number of filter layer outlets where bubbles continuously appear in each modified filter layer within a preset time, and compares it with the total number of filter layer outlets of the corresponding modified filter layer to obtain the pore passing rate of each modified filter layer.

[0025] As a preferred technical solution of the deep-bed denitrification water treatment system with synergistic effect of functional filter materials, the process control module determines whether the current layer water flow is normally distributed according to the water flow stability characterization parameter, including:

[0026] If the water flow stability characterization parameter is less than or equal to the standard stability characterization parameter, the current layer water flow is normally distributed;

[0027] If the water flow stability characterization parameter is greater than the standard stability characterization parameter, the current layer water flow is abnormally distributed.

[0028] As a preferred technical solution of the deep-bed denitrification water treatment system with synergistic effect of functional filter materials, the process control module is configured to adjust the current modified filter layer in combination with the tilt angle in response to the determination result of abnormal current layer water flow distribution, specifically including:

[0029] If the tilt angle is not 0, the process control module calibrates the tilt angle of the current modified filter layer;

[0030] If the tilt angle is 0, the process control module increases the diameter of the outlet of the current modified filter layer.

[0031] As an optimal technical solution of a deep-bed denitrification water treatment system with synergistic enhancement of functional filter media, the processing control module determines whether there is an abnormality in nitrogen emission according to the pore passing rate of the modified filter layer, including:

[0032] If the pore passing rate is greater than the standard passing rate, the processing control module determines that there is no abnormality in nitrogen emission and does not increase the number of modified filter layers.

[0033] If the pore passing rate is less than or equal to the standard passing rate, the processing control module determines that there is an abnormality in nitrogen emission and increases the number of modified filter layers by one layer.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: through innovative filter media design, intelligent detection and dynamic regulation modules, the present invention achieves an efficient denitrification treatment effect. The system adopts honeycomb diversion filter bricks covered with a nano-hydrophilic coating, and its internal diversion holes are connected with the swirl channels, which can effectively guide the water flow to rise evenly and optimize the path, reduce the short-circuit phenomenon, improve the nitrogen gas discharge efficiency at the same time, and reduce the risk of air blockage. The filter media module composed of ceramic fiber, modified zeolite and silane coupling agent not only improves the adhesion performance of denitrifying bacteria, but also realizes the slow-release function of carbon source and improves the carbon source utilization rate. The detection module constructs a water flow characterization vector group to accurately evaluate the water flow stability, and combines with the processing control module to dynamically adjust the inclination angle or outlet diameter of the filter layer to ensure uniform water flow distribution. In addition, the system intelligently judges whether there is an abnormality in nitrogen emission according to the pore passing rate, and increases the number of filter layers when necessary, further refining the water flow and bubbles to ensure the smooth discharge of gas. The present invention not only significantly reduces the carbon source dosage and backwashing frequency, reduces the operation cost, but also improves the stability of the effluent water quality, enables the total nitrogen concentration of the effluent to reach the standard stably, and prolongs the service life of the filter material at the same time, providing a strong guarantee for the efficient and stable operation of the sewage treatment plant.

[0035] In particular, in the present invention, through the synergistic effect of the detection module and the processing control module, the accurate evaluation and regulation of the water flow stability of the denitrification deep-bed filter tank are realized. The detection module constructs a characterization vector group based on the water flow direction and speed, and then calculates the sum vector, the average deviation of the modulus length and the average value of the modulus length, and determines the water flow stability characterization parameter in combination with the sum vector angle to determine the uniformity of the water flow in the filter tank. In addition, the average deviation angle of the flow velocity vector is statistically calculated. The processing control module judges whether the current layer of water flow meets the water flow uniformity according to the comparison between the water flow stability characterization parameter and the standard stability characterization parameter, which not only ensures the uniform distribution of the water flow in the filter tank, optimizes the denitrification effect, but also reduces the gas discharge resistance and improves the overall operation efficiency, providing a strong guarantee for the efficient and stable operation of sewage treatment.

[0036] In particular, in the present invention, through dynamic adjustment and intelligent control, the problems of uneven water flow distribution and abnormal gas emission in the denitrifying deep bed filter are effectively solved. When it is detected that the water flow does not meet the uniform condition, the processing control module can take targeted measures according to the specific situation. This dynamic adjustment method not only improves the uniformity of the water flow, but also reduces the resistance and energy consumption during the operation of the system. In addition, the solution determines whether the nitrogen emission is abnormal by monitoring the pore passing rate of the modified filter layer. When the pore passing rate is lower than the standard value, the system automatically adds an additional layer of modified filter layer to refine the water flow and bubbles, ensuring the smooth discharge of gas, effectively coping with the high gas generation rate, and ensuring the stable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a structural block diagram of a deep bed denitrification water treatment system with synergistic enhancement of functional filter materials according to an embodiment of the present invention;

[0038] Figure 2 is a schematic diagram for comparing the contact angle modification of a nano-hydrophilic coating according to an embodiment of the present invention;

[0039] Figure 3 is a sectional view of a honeycomb diversion filter brick according to an embodiment of the present invention;

[0040] Figure 4 is a logic diagram for determining whether the water flow in the current layer is normally distributed according to an embodiment of the present invention;

[0041] In the figure: 1, inverted conical diffusion holes; 2, spiral through-flow holes. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] In order to make the objectives and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only for explaining the present invention and are not used to limit the present invention.

[0043] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only for explaining the technical principles of the present invention and do not limit the protection scope of the present invention.

[0044] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0045] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "installation", "connection", and "linkage" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] Please refer to Figure 1 as shown, which is a structural block diagram of a deep-bed denitrification water treatment system with synergistic effect of functional filter media according to an embodiment of the present invention; the present invention provides a deep-bed denitrification water treatment system with synergistic effect of functional filter media, including:

[0047] A filter tank module, which includes a building tank body and several modified filter layers, and is used to provide a basic space for treating nitrogen-containing sewage;

[0048] An inlet water module, which is connected to the bottom of the filter tank module and is used to convey the nitrogen-containing sewage into the building tank body;

[0049] A filter media module, which is arranged inside the filter tank module and above the inlet water module, and is used to adsorb small-molecule organic matter in the nitrogen-containing sewage and provide attachment sites for denitrifying bacteria;

[0050] A collection module, which is connected to the filter tank module and is used to continuously collect the nitrogen and nitrogen-free wastewater obtained after treating the nitrogen-containing sewage;

[0051] A detection module, which is respectively connected to the filter tank module, the inlet water module, and the collection module, and is used to detect the water flow direction and water flow velocity of the nitrogen-containing sewage to determine the water flow stability characterization parameters, and obtain the inclination angles and pore passing rates of the modified filter layers;

[0052] A treatment control module, which is respectively connected to the filter tank module, the inlet water module, and the detection module, and is used to determine whether the current layer of water flow is normally distributed according to the water flow stability characterization parameters, determine whether to adjust the corresponding modified filter layer according to the judgment result of normal water flow distribution combined with the inclination angles of the modified filter layers, and determine whether there is an abnormality in nitrogen emission according to the pore passing rate of the modified filter layer to determine whether to increase the number of modified filter layers.

[0053] In implementation, the number of modified filter layers is not less than 2.

[0054] The collection module is provided with a gas collection channel along the water flow direction. Nitrogen rises with the water flow to the gas collection area and is discharged, reducing the eddy current resistance by about 30% - 50%. The co-directional flow of gas and water can prevent the formation of gas film accumulation on the surface of the filter media, reduce gas blockage, and lower the backwashing frequency by more than 30%. At the same time, nitrogen is continuously discharged with the water flow, eliminating the need to frequently trigger the exhaust valve, and the nitrogen discharge cycle can be extended to 8 - 12 hours.

[0055] In the above embodiment, through innovative filter media design, intelligent detection, and dynamic regulation modules, an efficient denitrification treatment effect is achieved. The system uses honeycomb diversion filter bricks covered with a nano-hydrophilic coating, and its internal diversion holes are connected to spiral channels, which can effectively guide the water flow to rise evenly and optimize the path, reducing the short-circuit phenomenon. At the same time, it improves the nitrogen discharge efficiency and reduces the risk of gas blockage. The filter media module composed of ceramic fiber, modified zeolite, and silane coupling agent not only enhances the attachment performance of denitrifying bacteria but also realizes the slow-release function of the carbon source, improving the carbon source utilization rate. The detection module accurately evaluates the water flow stability by constructing a water flow characterization vector group and dynamically adjusts the inclination angle or outlet diameter of the filter layer in combination with the treatment control module to ensure uniform water flow distribution. In addition, the system intelligently judges whether the nitrogen emission is abnormal according to the passing rate of the guide holes and increases the number of filter layers when necessary to further refine the water flow and bubbles, ensuring the smooth discharge of gas. This not only significantly reduces the carbon source dosage and backwashing frequency, cuts down the operating cost, but also improves the stability of the effluent water quality, making the total nitrogen concentration in the effluent meet the standard stably. At the same time, it extends the service life of the filter media, providing a strong guarantee for the efficient and stable operation of the sewage treatment plant.

[0056] Please refer to Figure 2 and Figure 3 as shown in Figure 2 which is a schematic diagram of the contact angle modification comparison of the nano-hydrophilic coating in the embodiment of the present invention, Figure 3 and this is a cross-sectional view of the honeycomb diversion filter brick in the embodiment of the present invention. The modified filter layer is composed of honeycomb diversion filter bricks covered with a nano-hydrophilic coating;

[0057] Among them, several spiral-shaped guiding through-holes 2 are arranged inside the honeycomb diversion filter brick.

[0058] In implementation, the top of the honeycomb diversion filter brick is an inverted conical diffusion hole 1, which further disperses the water flow to avoid short-circuiting. Guided by the internal diversion holes, the water flow rises evenly from the bottom and then further optimizes the water flow path through the spiral channels, causing the water flow to form a spiral motion on the surface of the filter brick, increasing the contact time between the water flow and the filter media, and improving the efficiency of the denitrification reaction. At the same time, this connected design also helps to discharge nitrogen and reduce the gas blockage phenomenon.

[0059] In implementation, each honeycomb diversion filter brick has at least two spiral-shaped guiding through-holes 2, Figure 3 and there are 9 spiral-shaped guiding through-holes 2 in

[0060] It is understandable that after the water flow evenly rises from the internal diversion holes, the path is further optimized through the spiral flow channels, reducing the short-circuit flow phenomenon. Nitrogen can follow the water flow and be smoothly discharged through the internal diversion holes and spiral flow channels, reducing air blockage. In addition, the contact time between the water flow and the filter media can be increased, making the denitrification reaction more complete.

[0061] The nano-hydrophilic coating adopts a silica / titania-based sol-gel coating, which transforms the surface of the filter media from hydrophobic (contact angle > 90°) to super-hydrophilic (contact angle < 10°), enabling the water flow to spread rapidly in a thin film rather than as discrete water droplets, reducing local high-speed flow regions and avoiding short-circuit flow.

[0062] Specifically, the steps for obtaining the honeycomb diversion filter brick covered with the nano-hydrophilic coating include:

[0063] (1) Raw material weighing: TEOS, deionized water, ethanol, and nitric acid are weighed in a molar ratio of 1:4:1:0.05;

[0064] (2) Preparation of the precursor solution: Deionized water and ethanol are mixed to obtain a mixed solution containing deionized water and ethanol. TEOS is added dropwise to the above mixed solution and continuously stirred to obtain the precursor solution;

[0065] (3) Hydrolysis and polycondensation reaction, under the conditions of room temperature (25 ± 2 °C) or water bath heating (40 - 60 °C); the pH of the precursor solution is finely adjusted to alkaline (pH 9 - 10) through ammonia water to inhibit excessive hydrolysis, and then nitric acid is slowly added to adjust the pH to 8 - 10 to promote the hydrolysis reaction. Stir continuously for 30 minutes until the solution becomes transparent to form a stable sol, and continue to stir the stable sol for 6 - 12 hours for the polycondensation reaction to form a semi-transparent sol;

[0066] (4) The filter brick substrate (such as HDPE, ceramic) needs to be treated by plasma or chemical etching to increase the surface roughness and active groups (including -OH and -COOH), improving the coating adhesion. High-pressure airless spraying (pressurizing the semi-transparent sol to a pressure of 10 MPa - 15 MPa through a pressure pump) or electrostatic spraying (electrostatic voltage 60 - 90 KV, pressure set at 0.3 - 0.5 MPa) is used to control the coating thickness to 200 - 500 nm. After spraying, heat treatment is carried out at 80 - 120 °C for curing, and baking is carried out for 2 - 4 hours to accelerate the gel curing and form a stable coating structure;

[0067] (5) Use a contact angle measuring instrument to verify the hydrophilicity. By measuring that the contact angle is reduced from 108° before modification to about 10°, the preparation of the honeycomb diversion filter brick covered with the nano-hydrophilic coating is completed;

[0068] It is understandable that if the nano-hydrophilic coating is too thick, there is a risk of cracking. If the nano-hydrophilic coating is too thin, the coating coverage rate is insufficient, affecting the spread of the water flow thin film layer.

[0069] Specifically, the water inlet module includes:

[0070] A lower water inlet diversion unit for delivering the nitrogen-containing sewage to the building pool body at a preset water flow rate;

[0071] A layered water distribution unit connected to the lower water inlet diversion unit for dividing the nitrogen-containing sewage into several vertically upward filtering water flows.

[0072] In implementation, the number of filtering water flows is determined according to the bottom area of the building pool body. The filtering water flows are spaced equally in the vertical direction, and the filtering water flows in different columns are spaced equally in the horizontal direction. Preferably, the spacing in each direction is 30 cm to 50 cm.

[0073] Specifically, the filter media module includes functional filter media and volcanic rock activated carbon;

[0074] Among them, the functional filter media is composed of ceramic fiber, modified zeolite, and silane coupling agent.

[0075] In implementation, the compressive strength of the ceramic fiber ≥ 0.80 MPa, and the mass ratio of the ceramic fiber, modified zeolite, and silane coupling agent is 5:4:1.

[0076] In this embodiment, the volcanic rock activated carbon is arranged on the upper part of the functional filter media.

[0077] Specifically, the steps for obtaining the functional filter media include:

[0078] (1) Prepare ceramic fiber. Mix quartz sand, alumina powder, and calcium carbonate in proportion, place them in a high-temperature furnace and melt at 1600 - 1700 °C to form glass liquid. The glass liquid is ejected through a platinum-rhodium alloy spinneret (aperture 10 - 15 μm) and enters a 200 - 300 °C air quenching zone to form primary fibers. The primary fibers are subjected to multi-hole stretching through a bunching cylinder (stretching ratio 1:5 - 1:10) to eliminate bubbles and control the diameter. The primary fibers are cut, and fibers with a length of 10 - 15 mm are selected for moisture-proof packaging to obtain ceramic fiber;

[0079] (2) Prepare modified zeolite. Mix zeolite powder and ammonium nitrate in a mass ratio of 1:8, place them in a 90 °C water bath and stir for 4 hours. After centrifugal washing to neutrality, dry at 120 °C and calcine at 500 °C for 3 hours to remove crystal water and expand the pores;

[0080] (3) Prepare the functional filter media. Configure an ethanol solution of silane coupling agent (the concentration of silane coupling agent is 5%, and the solvent is ethanol). Immerse the prepared ceramic fibers and modified zeolites into it. Stir for 2 hours under the condition of constant temperature at 60°C and then centrifuge and dry. Roast the centrifuged and dried composite filter media in a nitrogen atmosphere at 200°C for 2 hours to fix the functional groups and obtain the functional filter media.

[0081] It can be understood that the modified zeolite increases the porosity through acid treatment (specific surface area ≥ 800 m² / g), preferentially adsorbs small molecule organic substances in water (such as sodium acetate, glucose, amino acids, etc.), and slowly releases them under anoxic conditions for directional cultivation of biofilms. The microporous structure (pore diameter 5 - 10 μm) of the ceramic fiber matrix provides high attachment sites for denitrifying bacteria, and the internal carbon source utilization rate is increased to more than 40%.

[0082] Specifically, the water flow direction and water flow velocity of the nitrogen-containing sewage detected by the detection module specifically include the first water flow direction and the first water flow velocity of each filtered water flow, and the second water flow direction and the second water flow velocity of the water flow at the outlet of each first-layer modified filter layer.

[0083] Among them, the quantities of the first water flow direction and the first water flow velocity are the same as the quantity of the filtered water flow.

[0084] The quantities of the second water flow direction and the second water flow velocity are the same as the quantity of the outlet of the modified filter layer.

[0085] In implementation, obtain the bubble movement direction and bubble movement velocity of the uppermost filter bricks of each modified filter layer in the vertical direction of the filtered water flow. Obtain the continuous movement images of the bubbles by setting high-speed cameras (≥ 1000 fps, such as Phantom VEO 410) in multiple directions. Combine image processing technology, use displacement vector angles to calculate the bubble movement direction, and determine the bubble movement velocity according to the shooting time interval and the positions of the bubbles in different images to equivalently determine the water flow direction and water flow velocity at the outlet of the corresponding layer.

[0086] In implementation, there is a spacing of at least 1 cm between any two adjacent modified filter layers.

[0087] The detection module also obtains all the third water flow directions and the third water flow velocities of the water flow at the outlet of the second-layer modified filter layer until all the (n + 1)th water flow directions and the (n + 1)th water flow velocities of the water flow at the outlet of the nth-layer modified filter layer.

[0088] Specifically, the detection module constructs a characterization vector group of the filtered water flow according to all the first water flow directions and the corresponding first water flow velocities, and calculates the sum vector, the average deviation of the modulus length, and the average value of the modulus length of the characterization vector group.

[0089] The detection module determines the water flow stability characterization parameter based on the ratio of the average deviation of the module length to the average value of the module length and the angle of the sum vector.

[0090] In implementation, the water flow stability characterization parameter is determined by the product of the ratio of the average deviation of the module length to the average value of the module length and the ratio of the angle of the vector to the standard water flow deviation angle.

[0091] The detection module determines the water flow stability characterization parameters of each modified filter layer in the same way.

[0092] Specifically, according to the path of bubble movement, the water flow trajectory is analyzed by CFD (Computational Fluid Dynamics) simulation, the average deviation angle of the flow velocity vector is statistically calculated. According to the "Outdoor Drainage Design Standard" GB 50014-2021, the design of the filter water distribution system should ensure that the deviation angle is about ≤5°, and the standard water flow deviation angle is 5°.

[0093] Specifically, the detection module obtains the number of filter layer outlets where bubbles continuously appear in each modified filter layer within a preset time, and divides it by the total number of filter layer outlets of the corresponding modified filter layer to obtain the pore passing rate of each modified filter layer.

[0094] In implementation, the preset time is not less than 60s, preferably 120s.

[0095] In this embodiment, a high-speed camera is used to observe the surface of the diversion filter brick, the ratio of the number of open inverted holes to the total number of inverted holes per unit area is statistically calculated, and quantitative analysis is performed through image processing software to obtain the number of filter layer outlets where bubbles appear. In implementation, it can also be replaced by other methods that can determine the number of filter layer outlets where bubbles appear, which will not be elaborated here.

[0096] Please refer to Figure 4 As shown, it is a logic diagram for determining whether the water flow of the current layer is normally distributed in the embodiment of the present invention. The process control module determines whether the water flow of the current layer is normally distributed based on the water flow stability characterization parameter, including:

[0097] If the water flow stability characterization parameter is less than or equal to the standard stability characterization parameter, the water flow of the current layer is normally distributed;

[0098] If the water flow stability characterization parameter is greater than the standard stability characterization parameter, the water flow of the current layer is abnormally distributed.

[0099] In implementation, the standard stability characterization parameter is selected within the range of [0.1, 0.15].

[0100] It can be understood that the allowable unevenness coefficient K of the denitrifying deep bed filter is ≤15%, and the deviation angle of the water flow in the ideal state in the vertical direction is less than 3°. At this time, the water flow uniformity is the best and the gas discharge resistance is small.

[0101] In the present invention, through the collaborative action of the detection module and the processing and control module, the accurate evaluation and regulation of the water flow stability of the denitrifying deep bed filter are realized. The detection module constructs a characterization vector group based on the water flow direction and velocity, and then calculates the sum vector, the average deviation of the modulus length, and the average value of the modulus length, and determines the water flow stability characterization parameter in combination with the sum vector angle to determine the degree of water flow uniformity in the filter. In addition, the average deviation angle of the flow velocity vector is statistically calculated. The processing and control module judges whether the current layer of water flow meets the water flow uniformity according to the comparison between the water flow stability characterization parameter and the standard stability characterization parameter, which not only ensures the uniform distribution of the water flow in the filter, optimizes the denitrification effect, but also reduces the gas discharge resistance, improves the overall operation efficiency, and provides a strong guarantee for the efficient and stable operation of the sewage treatment.

[0102] Specifically, the processing and control module is configured to adjust the current modified filter layer in combination with the tilt angle in response to the determination result of the abnormal distribution of the water flow in the current layer, specifically including:

[0103] If the tilt angle is not 0, the processing and control module calibrates the tilt angle of the current modified filter layer;

[0104] If the tilt angle is 0, the processing and control module increases the diameter of the outlet of the current modified filter layer.

[0105] In implementation, the increased amount of the diameter of the outlet of the modified filter layer is determined according to the product of the difference between the water flow stability characterization parameter and the standard stability characterization parameter and the current diameter.

[0106] Specifically, the processing and control module determines whether there is an abnormality in nitrogen emission according to the pore passing rate of the modified filter layer, including:

[0107] If the pore passing rate is greater than the standard passing rate, the processing and control module determines that there is no abnormality in nitrogen emission and does not increase the number of modified filter layers.

[0108] If the pore passing rate is less than or equal to the standard passing rate, the processing and control module determines that there is an abnormality in nitrogen emission and increases the number of modified filter layers by one layer.

[0109] In implementation, the standard passing rate is 80%.

[0110] It can be understood that when the passing rate ≥ 70%, it is generally considered that the gas can be effectively discharged and has little impact on the system. For the scenario of high-load denitrification (large gas production), generally, the passing rate needs to be greater than 80% to cope with the high gas generation rate. Increasing the number of modified filter layers can further refine the water flow and bubbles to ensure the smooth discharge of gas.

[0111] In the present invention, through dynamic adjustment and intelligent control, the problems of abnormal water flow and abnormal gas emission in the denitrifying deep bed filter are effectively solved. When it is detected that the water flow does not meet the uniform condition, the processing control module can take targeted measures according to the specific situation. This dynamic adjustment method not only improves the uniformity of the water flow, but also reduces the resistance and energy consumption during the operation of the system. In addition, the scheme judges whether the nitrogen emission is abnormal by monitoring the pore passing rate of the modified filter layer. When the pore passing rate is lower than the standard value, the system automatically adds an additional layer of modified filter layer to refine the water flow and bubbles, ensuring the smooth discharge of gas, and can effectively cope with the high gas generation rate to ensure the stable operation of the system.

[0112] Example 1

[0113] Previously, a traditional up-flow deep bed denitrifying filter was used, and the TN fluctuation of the effluent was 8 - 12 mg / L (national standard requirement ≤ 10 mg / L), the proportion of carbon source cost reached 38%, and the backwashing frequency was 48 h / time.

[0114] Reconstruction target: TN stable ≤ 5 mg / L (local environmental protection requirement), carbon source cost reduced by 30%, and backwashing cycle extended to more than 72 h.

[0115] Filter reconstruction: The honeycomb diversion filter bricks covered with nano-hydrophilic coating are used for the inlet water, replacing the original perforated pipe water distribution system. Honeycomb filter bricks (material: HDPE + nano-SiO2 hydrophilic coating) are adopted, and the diversion holes are spirally distributed; a double-layer composite filter material is set, the lower layer is a functional filter material (particle size 3 - 5 mm, carbon release rate 15 mg / (L·h)), and the upper layer is volcanic rock activated carbon loaded with denitrifying bacteria (particle size 2 - 4 mm). A jet mixer is installed at the bottom of the filter, and the sodium acetate dosage is dynamically adjusted in combination with an online nitrate sensor (C / N ratio reduced from 4.5 to 3.2).

[0116] Operating parameters: Hydraulic load: 8 m³ / (m²·h); effluent TN: ≤ 5 mg / L, COD / TN ratio: 2.8 - 3.5;

[0117] This example achieved a 30% reduction in the carbon source dosage.

[0118] Example 2

[0119] For the treatment of high-nitrate wastewater in industrial parks, the inlet TN is as high as 80 - 120 mg / L (mainly nitrate), and the C / N ratio is only 1.5 - 2.0. The original process adopted two-stage AO (anoxic-aerobic process) + ordinary filter, and the effluent TN ≥ 25 mg / L, which could not meet the requirement of ≤ 15 mg / L in the park.

[0120] Filter tank reconstruction: honeycomb filter bricks covered with nano hydrophilic coating are used for inlet water to replace the original perforated pipe water distribution system. Honeycomb filter bricks (material: HDPE + nano SiO2 hydrophilic coating) are used, and the diversion holes are spirally distributed; double-layer composite filter material is set, the lower layer is functional filter material (particle size 3-5mm, carbon release rate 15mg / (L·h)), and the upper layer is volcanic rock activated carbon loaded with denitrifying bacteria (particle size 2-4mm). Multi-stage honeycomb filter bricks for lower inlet water: replace the original perforated pipe water distribution system, and use honeycomb filter bricks (material: HDPE + nano SiO2 hydrophilic coating), and the diversion holes are spirally distributed (edge hole density +20%). A jet mixer is installed at the bottom of the filter tank, and the dosage of sodium acetate is dynamically adjusted in combination with an online nitrate sensor (C / N ratio is reduced from 4.5 to 3.2).

[0121] Operation parameters: hydraulic load is 0.5 m³ / (m²·h); outlet water TN≤15 mg / L;

[0122] Carbon source supplement: Only 30 kg / d of methanol needs to be added (the original process requires 150 kg / d), and the filter brick slowly releases the carbon source to meet 60% of the demand;

[0123] Denitrification rate increased to 0.35 kg NO3 - -N / (m³·d).

[0124] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A deep-bed denitrification water treatment system with synergistic effect of functional filter media, characterized in that Comprising: A filter module, which includes a building tank body and a number of modified filter layers, for providing a basic space for treating nitrogen-containing sewage; An inlet module, which is connected to the bottom of the filter module, for conveying the nitrogen-containing sewage into the building tank body; A filter media module, which is arranged inside the filter module and above the inlet module, for adsorbing small molecule organic matters in the nitrogen-containing sewage and providing attachment sites for denitrifying bacteria; A collection module, which is connected to the filter module, for continuously collecting nitrogen gas and nitrogen-free wastewater obtained after treating the nitrogen-containing sewage; A detection module, which is respectively connected to the filter module, the inlet module and the collection module, for detecting the water flow direction and water flow velocity of the nitrogen-containing sewage to determine the water flow stability characterization parameters, and obtaining the inclination angle and pore passing rate of each modified filter layer; A treatment control module, which is respectively connected to the filter module, the inlet module and the detection module, for determining whether the current layer water flow is normally distributed according to the water flow stability characterization parameters, determining whether to adjust the corresponding modified filter layer according to the judgment result of normal water flow distribution combined with the inclination angle of each modified filter layer, and determining whether there is an abnormality in nitrogen emission according to the pore passing rate of the modified filter layer to determine whether to increase the number of modified filter layers; The modified filter layer is composed of honeycomb diversion filter bricks covered with a nano-hydrophilic coating; Wherein, a number of spiral through-holes are arranged inside the honeycomb diversion filter brick; The detection module obtains the number of filter layer outlets with continuous bubbles in each modified filter layer within a preset time, and compares it with the total number of filter layer outlets of the corresponding modified filter layer to obtain the pore passing rate of each modified filter layer.

2. The deep-bed denitrification water treatment system with synergistic effect of functional filter media according to claim 1, wherein The inlet module includes: A lower inlet diversion unit, which conveys the nitrogen-containing sewage to the building tank body at a preset water flow velocity; A layered water distribution unit, which is connected to the lower inlet diversion unit, for dividing the nitrogen-containing sewage into a number of vertically upward filtered water flows.

3. The deep-bed denitrification water treatment system with synergistic effect of functional filter media according to claim 1, wherein The filter media module includes functional filter media and volcanic rock activated carbon; Wherein, the functional filter media is composed of ceramic fiber, modified zeolite and silane coupling agent.

4. The deep-bed denitrification water treatment system with synergistic effect of functional filter media according to claim 1, characterized in that, The water flow direction and water flow velocity of the nitrogen-containing sewage detected by the detection module specifically include the first water flow direction and the first water flow velocity of each filtered water flow, and the second water flow direction and the second water flow velocity of each outlet of the first-layer modified filter layer; Wherein, the number of the first water flow direction and the first water flow velocity is the same as the number of filtered water flows; The number of the second water flow direction and the second water flow velocity is the same as the number of filter layer outlets of the modified filter layer.

5. The deep-bed denitrification water treatment system with synergistic effect of functional filter media according to claim 4, characterized in that The detection module constructs a characterization vector group of the filtered water flow according to all the first water flow directions and the corresponding first water flow velocities, and calculates the sum vector, the average deviation of the modulus length and the average value of the modulus length of the characterization vector group; The detection module determines the water flow stability characterization parameter according to the ratio of the average deviation of the modulus length to the average value of the modulus length and the angle of the sum vector.

6. The deep bed denitrification water treatment system with synergistic effect of functional filter media according to claim 1, characterized in that, The treatment control module determining whether the current layer water flow is normally distributed according to the water flow stability characterization parameter includes: If the water flow stability characterization parameter is less than or equal to the standard stability characterization parameter, it is determined that the water flow distribution in the current layer is normal; If the water flow stability characterization parameter is greater than the standard stability characterization parameter, it is determined that the water flow distribution in the current layer is abnormal; Among them, the standard stability characterization parameter is selected within the interval [0.1, 0.15].

7. The deep bed denitrification water treatment system with synergistic effect of functional filter media according to claim 6, characterized in that, The processing control module is configured to adjust the current modified filter layer in combination with the tilt angle in response to the determination result of abnormal water flow distribution in the current layer, specifically including: If the tilt angle is not 0, the processing control module calibrates the tilt angle of the current modified filter layer; If the tilt angle is 0, the processing control module increases the diameter of the outlet of the current modified filter layer.

8. The deep-bed denitrification water treatment system with synergistic effect of functional filter media according to claim 1, characterized in that The processing control module determines whether there is an abnormality in nitrogen emissions according to the pore passing rate of the modified filter layer, including: If the pore passing rate is greater than the standard passing rate, the processing control module determines that there is no abnormality in nitrogen emissions and does not increase the number of modified filter layers; If the pore passing rate is less than or equal to the standard passing rate, the processing control module determines that there is an abnormality in nitrogen emissions and increases the number of modified filter layers by one layer; Among them, the standard passing rate is 80%.

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