A multi-stage synergistic ecological water purification system

Abstract

The utility model discloses a multistage coordinated ecological water quality purification system belongs to water quality purification technical field, including the intercept module, denitrification and phosphorus removal module and drop water type biological purification module of setting in the ditch, the intercept module, denitrification and phosphorus removal module and drop water type biological purification module are arranged in proper order according to the water flow direction, the intercept module includes the grating structure, and the cross section of grating structure is adapted with the ditch cross section, denitrification and phosphorus removal module includes the bottom mud capture well and denitrification and phosphorus removal unit, and denitrification and phosphorus removal unit installs in the bottom mud capture well, and the bottom mud capture well sinks below the ditch bottom, drop water type biological purification module includes a plurality of height gradient drop water unit that drops along the water flow direction. The utility model discloses drop water type biological purification module forms the continuous water curtain through multistage drop water unit, and the turbulent aeration effect is strengthened, need not aeration equipment, and energy consumption reduces.

Description

Technical Field

[0001] This utility model relates to the field of water purification technology, specifically to a multi-level collaborative ecological water purification system. Background Technology

[0002] Ecological ditches are ditch ecosystems composed of water, soil, and organisms, also known as farmland ditch wetland ecosystems. They utilize the "channel" characteristic of ditches connecting farmland with rivers and lakes, and purify water flow through engineering facilities (such as interception dams and control gates) and biological components (aquatic plants and microorganisms).

[0003] Traditional ecological ditch purification modules suffer from problems such as short hydraulic retention time, high cost of fillers, low nitrogen and phosphorus removal efficiency, and lack of ecological synergy. For example, Chinese patent document CN206232574U discloses a composite constructed wetland process system for nitrogen and phosphorus removal, including an inlet pipe, an outlet pipe, and a multi-stage composite constructed wetland connected in series between the inlet and outlet pipes; each stage of the composite constructed wetland includes an upstream aerobic biological pond and a downstream constructed wetland, and each constructed wetland includes several constructed wetland units; in the first stage of the composite constructed wetland, each constructed wetland unit is connected in parallel and is a vertical subsurface flow constructed wetland unit; in the other stages of the composite constructed wetland, the constructed wetland includes a group of several interconnected constructed wetland units, and each group is connected in parallel; the constructed wetland units in each group include both horizontal subsurface flow constructed wetland units and surface flow constructed wetland units. This composite constructed wetland system has a highly efficient nitrogen and phosphorus removal function, which can significantly improve water quality.

[0004] However, using a planar radial wetland unit combination requires additional aeration blowers, which increases energy consumption and operating costs. Utility Model Content

[0005] The purpose of this invention is to provide a multi-level collaborative ecological water purification system to solve the problem that the existing planar radial wetland unit combination requires additional aeration fans, resulting in increased energy consumption and high operating costs.

[0006] To achieve the above objectives, this utility model provides a multi-stage synergistic ecological water purification system, including an interception module, a nitrogen and phosphorus removal module, and a cascading biological purification module installed in a ditch; the interception module, nitrogen and phosphorus removal module, and cascading biological purification module are arranged sequentially in the direction of water flow; the interception module includes a grid structure, the cross-section of which is adapted to the cross-section of the ditch; the nitrogen and phosphorus removal module includes a sediment capture well and a nitrogen and phosphorus removal unit, the nitrogen and phosphorus removal unit being installed in the sediment capture well, the sediment capture well being submerged below the bottom of the ditch; the cascading biological purification module includes multiple cascading units whose height decreases gradually along the direction of water flow.

[0007] Furthermore, the grid tilt angle of the grid structure is 50° to 65°.

[0008] Furthermore, the grid structure includes multiple sets of parallel grid bars, each grid bar having a width of 9mm to 11mm and a gap between the grid bars of 19mm to 21mm.

[0009] Furthermore, the grid structure is a hierarchical grid structure, including a first-level grid and a second-level grid, wherein the aperture of the first-level grid is larger than the aperture of the second-level grid.

[0010] Furthermore, the width of the sediment capture well is not less than the width of the bottom of the ditch; multiple nitrogen and phosphorus removal units are staggered and spaced on the inner walls of the sediment capture well on both sides opposite to each other in the direction of water flow.

[0011] Furthermore, the denitrification and phosphorus removal unit is internally filled with a packing unit, the packing unit having a specific surface area of ​​350 m². 2 / g~390m 2 / g, with a micropore area ratio of 70% to 75%.

[0012] Furthermore, the cascading unit includes straight steps of the same width as the ditch, and the height of the multiple straight steps relative to the bottom of the ditch gradually decreases along the direction of water flow; a semi-open fish ladder is provided above the longitudinal axis of the straight steps.

[0013] Furthermore, the fish ladder is located on the side of the straight staircase opposite to the water flow direction and extends to the top of the straight staircase, and the opening width of the fish ladder at the top of the straight staircase accounts for 55% to 65% of the width of the straight staircase.

[0014] Furthermore, the side wall of the fish ladder is pre-set with a planting trough, which is used to plant emergent plants.

[0015] Furthermore, the bottom surface of the fish ladder is uneven.

[0016] Compared with existing known technologies, the technical solution provided by this utility model has the following beneficial effects:

[0017] This invention discloses a multi-stage synergistic ecological water purification system. The interception module, serving as the first pretreatment unit of the system, is designed based on fluid mechanics principles and bar filtration theory. It employs bar filtration technology to achieve graded interception of suspended solids, with the bar structure's cross-section adapted to the ditch cross-section to maximize filtration efficiency. A sediment capture well collects and settles mud and other impurities carried in the ditch water. A nitrogen and phosphorus removal unit removes nitrogen and phosphorus pollutants from the ditch water. A cascading biological purification module forms a continuous water curtain through multiple cascading units, enhancing turbulent aeration and improving biological purification efficiency. Compared to existing technologies, it eliminates the need for aeration equipment, reducing energy consumption. The interception module, nitrogen and phosphorus removal module, and cascading biological purification module work synergistically to construct a step-by-step ecological interception ditch purification system, achieving an organic unity between efficient pollutant removal and the restoration of the water body's ecological function.

[0018] It is obvious that the elements or features described in the above individual embodiments can be used alone or in combination in other embodiments. Attached Figure Description

[0019] The dimensions and scales in the accompanying drawings do not represent the actual dimensions and scales of the product. The drawings are for illustrative purposes only, and some non-essential elements or features have been omitted for clarity.

[0020] Figure 1 This is a top-down plan view of the multi-level collaborative ecological water purification system according to an embodiment of this utility model;

[0021] Figure 2 This is a schematic diagram of the tilt angle of the interception module grille in an embodiment of this utility model;

[0022] Figure 3 This is a schematic diagram of the structure of the nitrogen and phosphorus removal module and the cascading biological purification module in the embodiments of this utility model.

[0023] Explanation of reference numerals in the attached figures

[0024] 100. Interception module; 110. Bars; 200. Denitrification and phosphorus removal module; 210. Sediment capture well; 220. Denitrification and phosphorus removal unit; 300. Biological purification module; 310. Waterfall unit; 311. Straight steps; 312. Fish ladder. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings. The embodiments described herein are merely preferred embodiments of the present invention. Those skilled in the art can conceive of other ways to implement the present invention based on the preferred embodiments, and such other ways also fall within the scope of the present invention.

[0026] Reference Figures 1-3This embodiment provides a multi-stage synergistic ecological water purification system, including an interception module 100, a nitrogen and phosphorus removal module 200, and a cascading biological purification module 300 installed in a ditch. The interception module 100, nitrogen and phosphorus removal module 200, and cascading biological purification module 300 are arranged sequentially according to the water flow direction. In the water flow direction, the interception module 100 is in the first stage, the nitrogen and phosphorus removal module 200 is in the middle stage, and the cascading biological purification module 300 is in the last stage. The multiple modules work together step-by-step to achieve water purification. The interception module 100 includes a grid structure whose cross-section is adapted to the ditch cross-section. Its design is based on fluid mechanics principles and grid filtration theory, employing grid filtration technology to achieve graded interception of suspended solids. The cross-section of the grid structure is adapted to the ditch cross-section to maximize filtration efficiency. The nitrogen and phosphorus removal module 200 includes a sediment capture well 210 and a nitrogen and phosphorus removal unit 220. The nitrogen and phosphorus removal unit 220 is installed in the sediment capture well 210, which is submerged below the bottom of the ditch. The sediment capture well 210 is used to collect and settle impurities such as mud carried in the ditch water, while the nitrogen and phosphorus removal unit 220 can remove pollutants such as nitrogen and phosphorus from the ditch water. The cascading biological purification module 300 includes multiple cascading units 310 with a gradient height along the water flow direction. The cascading biological purification module 300 forms a continuous water curtain through the multi-stage cascading units 310, enhancing the turbulent aeration effect and improving the biological purification efficiency. The interception module 100, the nitrogen and phosphorus removal module 200, and the cascading biological purification module 300 work together to construct a step-by-step ecological interception ditch purification system, achieving the organic unity of efficient pollutant removal and water body ecological function restoration.

[0027] In some embodiments, such as Figure 1 and Figure 2 As shown, to address the clogging problem of floating garbage and large suspended solids in black and odorous water bodies, an interception module 100 is located at the entrance of the ditch. The interception module 100 employs a grid structure with a grid inclination angle of 50°–65°, preferably 60°, which is the optimal angle for mechanical cleaning. The grid structure includes multiple sets of parallel grid bars 110, each bar being 9mm–11mm wide, with a gap between bars of 19mm–21mm. The grid structure has a rectangular cross-section. Given the preferred grid inclination angle of 60°, 26 sets of grid bars 110 are preferred, with a single bar width of 10mm and a calculated gap of 20mm (Equation 1). The overall grid width is 0.8m, geometrically fitting the channel cross-section.

[0028] The operating parameters of the interception module 100 are based on a design flow rate of 0.2m. 3System planning was conducted: Based on Manning's formula and energy equation, the water depth in front of the screen was determined to be 0.4 m. Combined with the optimal mechanical cleaning angle of 60° for the screen inclination, the flow velocity through the screen was determined to be 0.9 m / s (Equation 2). Theoretical calculations show that at this flow velocity, the shear stress on the surface of the 110 screen bars reaches 3.2 N / m. 2 This effectively removes attached pollutants while limiting head loss to within 0.12m (Equation 3), meeting the system's gravity-flow operation requirements. To address flow fluctuations, the module is set with a 1.5 times variation coefficient and a 0.3m channel freeboard to ensure a flow rate within the 0.1-0.3m range. 3 Within a / s traffic range, the interception efficiency remains stable at over 89%.

[0029] Formula 1: Calculation of the gap between bars 110

[0030]

[0031] In the formula: b is the net spacing of the 110 bars, which is 20mm; B is the total width of the grid, which is 0.8m; n is the number of 110 bars, which is 26 groups; and s is the thickness of a single 100 bar, which is 10mm.

[0032] Equation 2 Calculation of flow velocity through the gate

[0033]

[0034] In the formula: Q is the design flow rate of 0.2 m³ / s. 3 / s, h is the water depth in front of the screen (0.4m), and α is the screen inclination angle (60°).

[0035] Equation 3 Head Loss Model

[0036]

[0037] In the formula: β is the shape factor of the grid bar 100, which is 1.79; s is the thickness of the grid bar 100, which is 10 mm; b is the net spacing of the grid bars 100, which is 30 mm; and g is the gravitational acceleration, which is 9.81 m / s². 2 .

[0038] It should be noted that the interception module 100 has a range of 0.1-0.3m. 3 It can maintain stable operation within a flow rate range of / s, and its retention efficiency for suspended solids with a particle size greater than 5mm reaches 92.7%. Furthermore, the detachable grid bar design extends the manual cleaning cycle to more than 72 hours.

[0039] Furthermore, the bar screen structure is a multi-stage bar screen structure, including a first-stage bar screen and a second-stage bar screen, with the aperture of the first-stage bar screen being larger than that of the second-stage bar screen. Specifically, the aperture of the first-stage bar screen is 8mm, and the aperture of the second-stage bar screen is 5mm. Through multi-stage interception, the clogging problem of traditional single-stage bar screens (efficiency ≤70%) is effectively avoided, while preserving the natural slope of the ditch and adapting to seasonal flow fluctuations in black and odorous water bodies. It should be noted that the bars 110 of the first-stage bar screen are located in the upper layer, and the bars 110 of the second-stage bar screen are located in the lower layer.

[0040] In some embodiments, such as Figure 1 and Figure 3 As shown, the width of the sediment capture well 210 is not less than the width of the bottom of the ditch; multiple denitrification and phosphorus removal units 220 are staggered on the inner walls of the sediment capture well 210 on both sides opposite to the water flow direction, forming an "S"-shaped flow channel in the sediment capture well 210. This prolongs the flow time of the water through the sediment capture well 210, allowing the water to fully contact the denitrification and phosphorus removal units 220 and improving the denitrification and phosphorus removal effect on the water flow. The sediment capture well 210 is made of plain concrete, and the denitrification and phosphorus removal units 220 are filled with packing units with a specific surface area of ​​350 m². 2 / g~390m 2 / g, with a micropore area ratio of 70%–75%. Preferably, the filler unit uses the developed straw-based Fe-N@MFC material, with a specific surface area of ​​386.51 m². 2 With a micropore content of 73.85%, this material provides abundant adsorption sites and exhibits high adsorption efficiency. Modified with iron-nitrogen co-doping, it simultaneously adsorbs pollutants such as phosphorus and ammonia nitrogen. Data from a regional test section shows that the denitrification and phosphorus removal module 200 achieved a total phosphorus removal rate of 84.3% and an ammonia nitrogen removal rate of 78.6%. In the persulfate (PDS) system, the degradation efficiency of tetracycline (TC) reached 90.50%, with a degradation rate of 0.3304 min. -1 The mineralization rate reaches 61.7%, exhibiting strong catalytic degradation capabilities. Furthermore, Fe-N@MFC exhibits a low iron ion leaching concentration (0.15 mg / L), and its performance remains stable after five cycles of recycling. Straw, being agricultural waste, is widely available and inexpensive, and the preparation process is simple. Compared to traditional ceramsite fillers, this reduces material costs and enables the resource utilization of agricultural waste.

[0041] In some implementations, such as Figure 1 and Figure 3As shown, the cascading unit 310 includes straight steps 311 of the same width as the ditch. The height of multiple straight steps 311 relative to the bottom of the ditch gradually decreases along the water flow direction. These multiple gradually decreasing straight steps 311 can create turbulent aeration, further increasing dissolved oxygen in the water and forming multi-stage cascading aeration, effectively alleviating the black and odorous water phenomenon. For example, a four-level longitudinal cascade (single-level height difference 18cm) can be set at the rear section of the ditch. The cascade width is the same as the ditch width, the horizontal length of the steps is 40cm, and the surface is paved with natural stone (roughness Ra = 3.5μm) and covered with an impermeable geomembrane. Compared to existing technologies, no aeration equipment is required, reducing energy consumption. A semi-open fish ladder 312 is opened above the longitudinal axis of the straight steps 311. The fish ladder 312 can create a natural fish migration ecological corridor at the connection of the straight steps 311. Fish ladder 312 is located on the side of straight step 311 opposite to the water flow direction and extends to the top of straight step 311. The opening width of fish ladder 312 at the top of straight step 311 accounts for 55% to 65% of the width of straight step 311, preferably 60%. The main body of fish ladder 312 is a rectangular structure (1.2m long × 0.4m wide × 0.3m deep), with 15cm high concrete side walls on both sides. Planting troughs are pre-set on the side walls of fish ladder 312. The planting trough at the top of straight step 311 is filled with planting soil for planting emergent plants, such as reeds and cattails. The plant roots secrete secretions to enhance the degradation of ammonia nitrogen and COD, further removing pollutants.

[0042] Furthermore, the bottom of Fish Ladder 312 is designed with an uneven surface. Specifically, the bottom of Fish Ladder 312 is paved with uneven stone, creating alternating hydrodynamic conditions of slow-flow and turbulent zones. Through hydraulic model testing and optimization, the flow velocity within Fish Ladder 312 is controlled at 0.3-0.5 m / s, which meets the requirements for crucian carp swimming upstream. Field measurements in a certain area show that the inclusion of three resting pools within Fish Ladder 312, i.e., a 0.6m long gentle slope before each cascade, significantly improves the success rate of loach swimming upstream.

[0043] In the description of this utility model, it should be noted that the terms "front," "rear," "left," "right," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0045] The scope of protection of this utility model is defined only by the claims. Thanks to the teachings of this utility model, those skilled in the art will readily recognize that alternative structures to the disclosed structure can be used as feasible alternative implementations, and that the disclosed implementations can be combined to produce new implementations, which also fall within the scope of the appended claims.

Claims

1. A multi-stage synergistic ecological water purification system, comprising an interception module (100), a nitrogen and phosphorus removal module (200), and a cascading biological purification module (300) installed in a ditch; characterized in that, The interception module (100), the denitrification and phosphorus removal module (200), and the cascading biological purification module (300) are arranged sequentially in the direction of water flow. The interception module (100) includes a grid structure, the cross-section of which is adapted to the cross-section of the ditch. The denitrification and phosphorus removal module (200) includes a bottom sediment capture well (210) and a denitrification and phosphorus removal unit (220), the denitrification and phosphorus removal unit (220) being installed in the bottom sediment capture well (210), the bottom sediment capture well (210) being submerged below the bottom of the ditch. The cascading biological purification module (300) includes multiple cascading units (310) whose height decreases gradually along the direction of water flow.

2. The multi-stage synergistic ecological water purification system according to claim 1, characterized in that, The grid tilt angle of the grid structure is 50° to 65°.

3. The multi-level synergistic ecological water purification system according to claim 2, characterized in that, The grid structure includes multiple sets of parallel grid bars (110), each grid bar (110) has a width of 9mm to 11mm, and the gap between the grid bars (110) is 19mm to 21mm.

4. The multi-stage synergistic ecological water purification system according to claim 2, characterized in that, The grid structure is a hierarchical grid structure, including a first-level grid and a second-level grid, wherein the aperture of the first-level grid is larger than that of the second-level grid.

5. The multi-stage synergistic ecological water purification system according to claim 1, characterized in that, The width of the sediment capture well (210) is not less than the width of the bottom of the ditch; multiple denitrification and phosphorus removal units (220) are staggered on the inner walls of the two sides opposite to each other in the direction of water flow of the sediment capture well (210).

6. The multi-level synergistic ecological water purification system according to claim 5, characterized in that, The denitrification and phosphorus removal unit (220) is internally filled with a packing unit, the specific surface area of ​​which is 350 m². 2 / g~390m 2 / g, with a micropore area ratio of 70% to 75%.

7. The multi-stage synergistic ecological water purification system according to claim 1, characterized in that, The drop unit (310) includes a straight step (311) of the same width as the ditch, and the height of the multiple straight steps (311) relative to the bottom of the ditch gradually decreases along the direction of water flow; a semi-open fish ladder (312) is provided above the longitudinal axis of the straight step (311).

8. The multi-stage synergistic ecological water purification system according to claim 7, characterized in that, The fish ladder (312) is located on the side of the straight step (311) opposite to the water flow direction and extends to the top of the straight step (311). The opening width of the fish ladder (312) at the top of the straight step (311) is 55% to 65% of the width of the straight step (311).

9. A multi-stage synergistic ecological water purification system according to claim 7, characterized in that, The side wall of the fish ladder (312) is pre-set with a planting trough, which is used to plant emergent plants.

10. A multi-stage synergistic ecological water purification system according to claim 7, characterized in that, The bottom surface of the fish ladder (312) is uneven.

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