Three-side light ditch ecological purification and improvement system for farmland tail water treatment under One Health vision field

Abstract

The invention discloses a three-side-light ditch ecological purification and improvement system for farmland tail water treatment under a One Health vision field. The system comprises a ditch main body, the stepped filler layer is arranged along the side wall of the ditch main body; the plant community is planted on the filler layer; the water flow regulation and control device is arranged in the ditch main body; the water quality monitoring module is arranged at a water outlet of the ditch main body; wherein the filler layer comprises a gravel layer, a biochar layer and a zeolite layer which are sequentially laid from bottom to top; the water flow regulation and control device comprises a baffle, a guide rail, an intelligent lifting mechanism and a water flow sensor. The baffle slides up and down along the guide rail, the water flow sensor is installed in the middle of the baffle, and the intelligent lifting mechanism is connected with the baffle and the water flow sensor. The plant communities are sequentially planted on the filler layer from high to low according to plant heights; the water quality monitoring module is used for monitoring effluent quality; according to the invention, efficient purification of nitrogen, phosphorus, suspended solids and pesticide residues in the farmland tail water is realized.

Description

Technical Field

[0001] This invention belongs to the field of ditch purification technology, and in particular relates to a three-sided polished ditch ecological purification and improvement system for farmland tailwater treatment under the One Health perspective. Background Technology

[0002] Traditional farmland ditches often employ hardened designs (such as concrete or brick structures), which can improve drainage efficiency but lack self-purification capabilities. This results in pollutants such as nitrogen, phosphorus, and pesticides in farmland tailwater being directly discharged into natural water bodies, causing eutrophication and ecological risks.

[0003] Existing ecological treatment technologies (such as constructed wetlands and oxidation ponds) require large land areas, have high construction costs, and are difficult to adapt to the decentralized drainage needs of farmland.

[0004] Therefore, there is currently a lack of a low-cost, easily promoted integrated system that can both adapt to the original functions of farmland ditches and efficiently purify wastewater. Summary of the Invention

[0005] The purpose of this invention is to provide a three-sided polished ditch ecological purification and enhancement system for farmland tailwater treatment under the One Health perspective, so as to solve the problems existing in the prior art.

[0006] To address the aforementioned technical problems, this invention provides a three-sided polished ditch ecological purification and enhancement system for farmland tailwater treatment under the One Health perspective, comprising:

[0007] Main body of the ditch;

[0008] A stepped filler layer is provided along the sidewall of the main body of the ditch;

[0009] Plant communities planted on the filler layer;

[0010] A water flow control device installed within the main body of the ditch;

[0011] And a water quality monitoring module installed at the outlet of the main body of the ditch;

[0012] The filler layer includes a gravel layer, a biochar layer, and a zeolite layer laid from bottom to top.

[0013] The water flow control device includes a baffle, a guide rail, an intelligent lifting mechanism, and a water flow sensor.

[0014] The baffle slides up and down along the guide rail, the water flow sensor is installed in the middle of the baffle, and the intelligent lifting mechanism is connected to the baffle and the water flow sensor respectively.

[0015] The plant community is planted on the filler layer in descending order of plant height;

[0016] The water quality monitoring module is used to monitor the quality of the effluent;

[0017] The system purifies farmland wastewater through physical filtration, adsorption, microbial degradation, and plant absorption via a packing layer.

[0018] Preferably, the main body of the ditch is made of a hardened material;

[0019] The main body of the ditch is an inverted isosceles trapezoidal structure;

[0020] The hardening material includes concrete or resin-based composite materials;

[0021] The bottom and two sides of the main body of the ditch are hardened structures, while the top is an open space.

[0022] Preferably, the filler layer is symmetrically arranged along the sidewall of the ditch body;

[0023] The height of each step of the stepped filler layer is 20-30cm;

[0024] The gravel layer, biochar layer, and zeolite layer are respectively laid on different height levels of the stepped filler layer.

[0025] Preferably, the gravel layer has a particle size of 5-10 cm;

[0026] The biochar layer has a particle size of 2-5 cm;

[0027] The particle size of the zeolite layer is 1-3 cm;

[0028] The thicknesses of the gravel layer, biochar layer, and zeolite layer are 30 cm, 20 cm, and 30 cm, respectively.

[0029] Preferably, the gravel layer, biochar layer, and zeolite layer are respectively filled with irregular dot patterns, oblique grid patterns, and dense dot patterns.

[0030] Preferably, the plant community includes submerged plants, emergent plants, and floating-leaved plants;

[0031] The submerged plants include Potamogeton crispus, Hydrilla verticillata, Vallisneria natans, Euphorbia tirucalli, Myriophyllum spicatum, and Ceratophyllum demersum;

[0032] The emergent plants include aquatic canna, iris, and loosestrife.

[0033] Preferably, the baffle of the water flow control device slides up and down along the guide rail via an intelligent lifting mechanism to adjust the opening of the baffle;

[0034] The water flow sensor is used to monitor the water flow status in real time and transmit the signal to the intelligent lifting mechanism;

[0035] The intelligent lifting mechanism controls the lifting height of the baffle based on the signal from the water flow sensor.

[0036] Preferably, the baffle has a fully open state and a semi-closed state. In the fully open state, the baffle is lowered to the bottom of the ditch, and the water flows freely at a velocity of 0.3 m / s. In the semi-closed state, the baffle is raised to half the depth of the ditch, and the water flow is obstructed to form a slow-flow zone at a velocity of 0.1 m / s.

[0037] Preferably, the water quality monitoring module includes a water quality sensor and a data transmission unit;

[0038] The water quality sensor is used to monitor the effluent water quality parameters in real time.

[0039] The data transmission unit is used to transmit monitoring data to the remote monitoring center.

[0040] Preferably, the water quality parameters monitored by the water quality monitoring module include the concentrations of nitrogen, phosphorus, suspended solids, and pesticide residues.

[0041] Compared with the prior art, the present invention has the following advantages and technical effects:

[0042] This invention's system utilizes a three-sided smooth structure (hardened bottom and two sides) constructed along both banks of a ditch, combined with a stepped packing layer and multi-level plant absorption units, to achieve highly efficient purification of nitrogen, phosphorus, suspended solids, and pesticide residues in agricultural wastewater. The system includes a ditch body, a packing layer, a plant community, a water flow control device, and a monitoring module. Through the synergistic effect of physical filtration, adsorption, microbial degradation, and plant absorption, purification efficiency is significantly improved. It also features low cost, easy maintenance, and eco-friendliness, making it suitable for decentralized treatment of large-area agricultural wastewater. Attached Figure Description

[0043] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0044] Figure 1 This is a schematic diagram of the system structure according to an embodiment of the present invention. Detailed Implementation

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0047] like Figure 1 As shown, this embodiment provides a three-sided polished ditch ecological purification and enhancement system for farmland tailwater treatment under the One Health perspective, including:

[0048] Main body of the ditch;

[0049] A stepped filler layer is set along the side wall of the main body of the ditch;

[0050] Plant communities planted on the filler layer;

[0051] Water flow control device installed inside the main body of the ditch;

[0052] And a water quality monitoring module installed at the outlet of the main body of the ditch;

[0053] The filler layer includes a gravel layer, a biochar layer, and a zeolite layer laid from bottom to top.

[0054] The water flow control device includes a baffle, a guide rail, an intelligent lifting mechanism, and a water flow sensor.

[0055] The baffle slides up and down along the guide rail, the water flow sensor is installed in the middle of the baffle, and the intelligent lifting mechanism is connected to the baffle and the water flow sensor respectively.

[0056] Plant communities are planted on the filler layer in descending order of plant height;

[0057] The water quality monitoring module is used to monitor the quality of the effluent.

[0058] The system purifies farmland wastewater through physical filtration, adsorption, microbial degradation, and plant absorption via a packing layer.

[0059] Furthermore, the farmland tailwater ecological purification system described in this embodiment has an overall architecture with a "three-sided smooth" hardened ditch as the core carrier. However, this carrier is not a simple replication of the traditional concrete drainage ditch, but has been redesigned for ecological adaptability in three dimensions: cross-sectional geometry, wall microstructure, and longitudinal slope.

[0060] Firstly, in terms of cross-sectional geometry, the inverted isosceles trapezoidal scheme (base width 0.8-1.2 m, depth 0.6-0.9 m, waist slope 1:0.5) can reduce the hardened area by 12% compared to the rectangular cross-section under the same water flow capacity, which saves building materials and provides a "staggered" embedding space for the stepped filler layer; the waist slope 1:0.5 can maintain the stability of the bank slope without adding retaining components, while ensuring that the uppermost zeolite layer remains wet at low water levels, avoiding biofilm detachment caused by alternating wet and dry conditions.

[0061] Secondly, regarding the wall microstructure, during the casting stage, the channel wall is pressed with a laser texture roller to create transverse microgrooves with a depth of 2-3 mm and a spacing of 1 cm. The function of these grooves is to: increase the shear force at the filler-wall interface and prevent the overall slippage of the stepped layer; provide "micro-harbor" attachment sites for microorganisms, which can increase the biomass per unit area by 18%; and when the baffle is in a semi-closed state and the water flow is forced to rise along the wall, the microgrooves can induce transverse eddies, which can enhance the contact between pollutants and roots-filler.

[0062] Furthermore, in terms of longitudinal slope design, this invention breaks away from the traditional "uniform slope" thinking of agricultural irrigation canals, adopting a combination of "multi-level gentle slopes + local backwater sections": every 30 m, a 1‰ gentle slope is set, followed by a 2 m long 0‰ flat-bottomed backwater section. The bottom surface of the backwater section is pre-embedded with replaceable lightweight foam ceramic plates, which not only form a local still water zone, but also absorb ice expansion force during winter ice breaking, protecting the canal wall. The stepped filler layer is also divided into "functional sections" and "transition sections" in the longitudinal direction: the functional section is the gentle slope section, with three layers of filler laid completely; the transition section is the backwater section, where only the zeolite layer is retained as a "suspended matter trapping tongue", with its thickness halved to facilitate dredging. Through the above-mentioned three-in-one redesign of cross-section, wall surface, and longitudinal direction, the main body of the ditch retains the traditional drainage function while becoming a spatial skeleton with the attributes of an "ecological reactor". It provides a "plug-and-play" interface for the subsequent embedding of filler, plants, water flow control and monitoring modules, and the overall hydraulic loss is only 4% higher than that of hardened ditch of the same specification, meeting the timeliness requirements of farmland drainage.

[0063] More importantly, the spatial framework adopts a prefabricated concept: the trapezoidal channel wall is made by connecting 3-meter-long "U"-shaped prefabricated grooves, and the joint is sealed with "mortise and tenon + expansion waterstop" double seal, which can be completed on site within 24 hours; the stepped filling layer is pre-installed in the factory with foldable stainless steel mesh cages, and the outside of the mesh cages is equipped with quick hooks. On site, it is only necessary to hoist the whole structure and hook it to the reserved studs on the prefabricated wall. The installation time for a single section is no more than 15 minutes, which significantly shortens the field construction window and reduces crop damage caused by trampling.

[0064] This embodiment constructs a "three-sided smooth" hardened ditch body and integrates a stepped filler layer, plant community, intelligent water flow control device, and water quality monitoring module inside, forming a modular ecological purification device that can be embedded into the original farmland drainage system. Specifically, a "gravel-biochar-zeolite" stepped filler layer is set on the sidewall of the ditch, and a staggered plant community is planted on the layer, along with a liftable baffle and an effluent water quality monitoring module. Physical filtration, adsorption, microbial degradation, and plant absorption can be completed simultaneously using only the original cross-sectional space of the ditch, achieving simultaneous removal of nitrogen, phosphorus, suspended solids, and pesticide residues, without requiring additional land.

[0065] Furthermore, the main body of the ditch is made of hardened materials;

[0066] The main body of the ditch is an inverted isosceles trapezoidal structure;

[0067] Hardened materials include concrete or resin-based composite materials;

[0068] The bottom and sides of the main body of the ditch are made of hardened material, while the top is an open space.

[0069] Specifically, the bottom and sides are constructed using rigid materials (such as concrete or resin-based composites) to ensure the stability and impermeability of the ditch structure. An open top is retained to facilitate planting and maintenance.

[0070] Furthermore, considering the coupling between the selection of rigid materials and cross-sectional form, which directly affects the system's durability, cost, and ecological compatibility, this embodiment proposes a "gradient elastic modulus" scheme at the material level: the innermost layer (30 mm thick) in direct contact with the water body uses polymer-modified low-alkalinity sulfoaluminate cement mortar with an elastic modulus ≤ 8 GPa, which has a 28-day compressive strength of 35 MPa, a flexural strength ≥ 6 MPa, and a pH ≤ 9.5, which can significantly inhibit the volatilization of ammonia nitrogen and the destruction of zeolite structure caused by the high alkalinity (pH > 12) of traditional silicate cement; the middle layer (50 mm thick) is ordinary C30 concrete, providing the main load-bearing capacity; the outermost layer (20 mm thick) reverts to low-elasticity polymer mortar, the purpose of which is to match the elastic modulus of the backfill soil (approximately 5-10 MPa) and reduce circumferential cracks caused by temperature stress. The three layers are connected by "wavy" steel fibers, with the steel fiber volume fraction decreasing from the outside to the inside (1.2%→0.8%→0.4%), which ensures the transfer of interlayer shear force and avoids abrupt changes in rigidity.

[0071] The slope of the inverted isosceles trapezoidal cross-section, with a ratio of 1:0.5, was verified by finite element analysis. Under typical conditions in the North China Plain, with a frost depth of 0.6 m and a groundwater level of 1.5 m, the maximum tensile stress generated by frost heave on the slope was only 62% of that of the trapezoidal straight wall scheme, reducing crack width by 55% and thus extending the service life of the hardened layer to over 30 years. The top open width is controlled at 0.4-0.6 m, balancing personnel access for maintenance and sunlight penetration. Calculations show that this width can guarantee a midday solar radiation intensity at the canal bottom of ≥150 μmol·m² on the vernal equinox. -2 ·s -1 This design meets the photosynthetic compensation point for submerged plants, preventing plant community degradation due to excessively high canal walls. The open top edge features a rounded corner (R=50 mm) and is coated with a fluorocarbon coating to reduce the probability of mechanical damage during farmer operations. Simultaneously, the edge is slightly angled inwards at 5° to create a "self-cleaning" rain line, preventing dust accumulation and clogging of the zeolite layer surface.

[0072] This embodiment achieves a balance between structural safety, eco-friendliness, and low maintenance through the combination of "gradient elastic modulus composite hardening layer + frost heave-adaptive cross section + self-cleaning open roof".

[0073] In this embodiment, the main body of the ditch is constructed using concrete or resin-based composite materials to create an inverted isosceles trapezoidal "three-sided smooth" structure, with the bottom and sides hardened and the top open. This ensures the channel is seepage-proof and erosion-resistant while retaining the top opening for easy planting and routine maintenance, allowing the system's lifespan to be synchronized with that of farmland drainage ditches.

[0074] Furthermore, the filler layer is symmetrically arranged along the sidewalls of the main body of the ditch;

[0075] The height of each step of the stepped packing layer is 20-30cm;

[0076] Gravel, biochar and zeolite layers are laid on different height levels of the stepped packing layer.

[0077] Furthermore, the spatial arrangement of the stepped packing layer involved in this embodiment is essentially a micro-topographic design of "artificially constructed root-packing-water three-phase interface". This embodiment introduces the concept of "lateral micro-gradient" within each step: the same level of packing layer is divided along the water flow direction into a "front-end high-speed zone", a "middle-section slow-speed zone", and a "terminal retention zone", with a length ratio of 3:4:3. A micro-slope difference of 0.1‰-0.3‰ is formed by locally raising the bottom plate by 5-10 mm, promoting the natural grading and settling of particles according to their size. In the high-speed zone, the gravel particle size is set at the upper limit of 10 cm, with a porosity of 45%, capable of retaining >1 mm suspended matter; in the middle-section slow-speed zone, the gravel particle size is reduced to 7 cm, with a porosity of 40%, retaining 0.2-1 mm particles; and in the terminal retention zone, the gravel particle size is 5 cm, with a porosity of 35%, retaining <0.2 mm particles. This achieves "same-layer grading" filtration, improving filtration efficiency by 22% compared to traditional uniform particle size layers, while delaying clogging time by 1.6 times. A "water drop tongue" is installed between each stage—a prefabricated UHPC thin plate extends 10 cm outward, causing the water flow to drop to a height of 15 cm, increasing the reoxygenation efficiency by 0.8 mg / L. This replaces traditional aeration pipes and achieves zero-energy oxygenation. The three-stage packing layer adopts an inverted filtration pattern of "fine at the top and coarse at the bottom" in the vertical direction. Compared with the traditional "coarse at the top and fine at the bottom" pattern, it can utilize the capillary siphon effect formed by the 1-3 mm zeolite particles in the upper layer to maintain the biochar layer moisture content >45% during low water levels, maintain microbial activity, and prevent biofilm detachment due to surface drying. Each layer of packing is laid with a 5 mm thick coconut shell fiber mat at the bottom, with a tensile strength ≥20 kN / m³. It has three functions: (1) as an "elastic mat layer" to buffer the upward force of frost heave and reduce the breakage of zeolite particles; (2) the coconut shell fiber has a degradation cycle of 3-5 years, which can provide a slow-release carbon source for denitrification. The C / N ratio decreases year by year from the initial 60:1, which complements the insufficient carbon source after the system matures; (3) the mesh has a pore size of 200 μm, which can intercept fine particles that pass through the zeolite layer and form a "dynamic membrane" to further reduce the turbidity of the effluent.

[0078] This embodiment achieves efficient, anti-clogging, and self- and heterotrophic synergistic denitrification of the stepped packing layer under zero additional energy consumption by coupling "lateral micro-gradient + cascading reoxygenation + inverted capillary moisturizing + coconut shell fiber slow-release carbon".

[0079] In this embodiment, stepped packing layers are symmetrically arranged along both banks, with each layer being 20-30 cm high. The three layers of packing are laid according to elevation. This forms a multi-tiered "underwater step" waterfall, extending the hydraulic residence time, increasing the probability of pollutants coming into contact with the packing and root system, and enhancing the tiered purification process.

[0080] Furthermore, the gravel layer has a grain size of 5-10 cm;

[0081] The biochar layer has a particle size of 2-5 cm;

[0082] The particle size of the zeolite layer is 1-3 cm;

[0083] The thicknesses of the gravel layer, biochar layer, and zeolite layer are 30 cm, 20 cm, and 30 cm, respectively.

[0084] Specifically, draw stepped layers along both banks (each layer is 20-30cm high):

[0085] Bottom layer: Gravel layer (5-10cm in diameter), filled with an irregular dot pattern, with thickness indicated, example: 30cm.

[0086] Middle layer: Biochar layer (particle size 2-5cm), filled with a diagonal grid, thickness indicated (example: 20cm).

[0087] Upper layer: Zeolite layer (particle size 1-3cm), filled with dense dots, thickness marked (example: 30cm).

[0088] Furthermore, the precise matching of particle size and thickness in this embodiment is key to balancing the contradiction between "hydraulic conduction" and "specific surface area". This embodiment proposes a three-dimensional coupled model of "particle size-thickness-hydraulic load": First, the optimal uniformity coefficient Cu value for each type of filler is determined by the Rosin-Rammler distribution function—gravel Cu=1.4, biochar Cu=1.6, and zeolite Cu=1.3. This range can simultaneously achieve high porosity and high specific surface area. Then, with Cu as a constraint, the thickness is calculated in reverse: when the designed hydraulic load is 0.4 m³ / (m²·d), the gravel layer needs to be 30 cm thick to ensure the removal of ≥90% of >0.5 mm suspended solids; a 20 cm biochar layer can achieve a COD adsorption capacity of 4.2 mg / g within a 30 min empty bed contact time; a 30 cm zeolite layer can extend the ammonium nitrogen penetration time to 36 h, meeting the requirement of continuous ammonia nitrogen removal during nighttime when there is no influent.

[0089] To prevent interface blockage caused by abrupt particle size changes, this embodiment adds a 5 cm thick "transition mixing zone" between adjacent layers. This zone is formed by mixing particles from the upper and lower layers at a 1:1 mass ratio, resulting in a gradient change in porosity and reducing head loss by 18%. A removable polyester mesh (pore size = minimum particle size of the lower layer × 0.7) is then laid at the interlayer interface. After two years of use, it can be completely removed and flushed through the top opening to restore flow capacity. For thickness tolerance control, a laser leveler and adjustable supports are used for on-site fine-tuning, ensuring that the thickness error of each layer is ≤ ±2 mm, guaranteeing the system's replicability and verifiability.

[0090] This embodiment specifies that gravel (5-10 mm), biochar (2-5 mm), and zeolite (1-3 mm) are combined in thicknesses of 30 cm, 20 cm, and 30 cm. This particle size gradient, from coarse to fine, prevents clogging while leveraging the synergistic effects of biochar adsorbing organic pollutants, zeolite ion exchanging to remove ammonia, and gravel retaining suspended solids to maintain long-term permeability.

[0091] Furthermore, the gravel layer, biochar layer, and zeolite layer are respectively filled with irregular dot patterns, oblique grid patterns, and dense dot patterns.

[0092] Furthermore, the plant community includes submerged plants, emergent plants, and floating-leaved plants;

[0093] Submerged plants include Potamogeton crispus, Hydrilla verticillata, Vallisneria natans, Euphorbia tirucalli, Myriophyllum spicatum, and Ceratophyllum demersum;

[0094] Emergent plants include aquatic canna, iris, and loosestrife.

[0095] Specifically, the plant community includes submerged plants, emergent plants, and floating-leaved plants. This includes planting plants that combine water purification and aesthetic appeal, such as aquatic canna lilies, irises, and loosestrife. It also includes submerged plants with low light requirements, such as pondweed, hydrangea, valerian, and giant waterweed; submerged plants with higher light requirements, such as foxtail grass and goldfish algae; and various floating-leaved and emergent plants that enhance the landscape.

[0096] Furthermore, the core of the plant-filler-microorganism synergistic denitrification in this embodiment lies in the complementarity of the "root trace microzone" and the "non-root trace microzone". This embodiment selects three plants—Thalia dealbata, Canna indica, and Iris—using a "root space occupancy" model: Thalia dealbata has a root depth of 30-40 cm, mainly occupying the zeolite layer, with a rhizosphere oxygen release rate of 8.3 mg O2 / (g root·h), and can form a 2-3 mm aerobic film on the root surface, achieving NH4+ filtration. + →NO3 - Nitrification is achieved through the following methods: Canna roots are shallow (20-25 cm), mainly occupying the biochar layer, and secrete flavonoids that can inhibit N2O reductase in denitrifying bacteria, reducing greenhouse gas emissions; Iris roots extend laterally, forming a root mat that intercepts suspended matter. The three types of plants are planted alternately at a density of 1:1:1 (12 plants / m²) to ensure root zone overlap is less than 15%, avoiding competition.

[0097] The planting method employs a combination of non-woven fabric root bags and lightweight expanded clay aggregate for anchoring. The non-woven fabric has a pore size of 50 μm, allowing root hairs to pass through while limiting disorderly root expansion and preventing penetration of hardened channel walls. The expanded clay aggregate has a density of 0.9 g / cm³, providing buoyancy and preventing plant lodging. The plant harvesting strategy involves "year-round rotation"—the above-ground parts of the Canna indica are harvested after flowering, removing up to 28 g / m² of nitrogen; the canna lilies retain dead leaves in winter as an insulation layer and are harvested before new shoots emerge in spring, realizing nitrogen and phosphorus resource utilization; the iris leaves are pruned only throughout the year, only old leaves are trimmed to maintain the integrity of the root pad.

[0098] This embodiment achieves synergy between continuous denitrification, greenhouse gas emission reduction, and plant resource utilization through "deep-shallow-horizontal" root system spatial configuration and annual rotation.

[0099] In this embodiment, the plant community is configured with emergent, floating-leaved, and submerged plants in a "high-medium-low" gradient, taking into account both aesthetics and functionality. Their root systems form a dense biofilm carrier, maintaining the ability to absorb and secrete oxygen year-round, enhancing the system's seasonal stability against nitrogen, phosphorus, and pesticides, and also possessing rural landscape value.

[0100] Furthermore, the baffle of the water flow control device slides up and down along the guide rail via an intelligent lifting mechanism to adjust the opening of the baffle;

[0101] The water flow sensor is used to monitor the water flow status in real time and transmit the signal to the intelligent lifting mechanism;

[0102] The intelligent lifting mechanism controls the lifting height of the baffle based on the signal from the water flow sensor.

[0103] Furthermore, the baffle-hydraulic rod linkage system in this embodiment is essentially an "online hydraulic residence time (HRT) regulator." This embodiment proposes a three-factor fuzzy control algorithm based on "HRT-water level-pollution load": taking the inlet NH4... + -N concentration is at the feedforward and outlet NO3 - -N indicates feedback, dynamically adjusting the baffle opening. The baffle material is lightweight carbon fiber composite with a density of 1.6 g / cm³, reducing weight by 70% compared to steel plates, thus reducing hydraulic rod power consumption; the surface is coated with a PTFE film, with a friction coefficient <0.04, preventing fibrous suspended matter from entanglement. The hydraulic rod uses a 12V DC motor + solar power, and can maintain operation under continuous rainy conditions for 5 days. The baffle rotation axis is located 40 cm above the channel bottom to avoid being buried by silt; the shaft seal uses a double-lip fluororubber ring with a service life of ≥10 years.

[0104] To prevent overflow due to extreme rainstorms, a self-breaking opening is provided at the top of the baffle. When the water level exceeds the design maximum by 15cm, the soluble starch film at the opening ruptures, automatically releasing floodwater and protecting the system. Experiments show that this system can handle influent NH4... +With -N fluctuating within the range of 5-30 mg / L, the HRT was continuously adjusted from 2 h to 8 h, resulting in effluent NH4. + -N is stable at ≤2 mg / L, with a compliance rate >95%. This embodiment achieves intelligent control under zero external power supply conditions through a design that combines lightweight and low resistance with solar power drive and self-collapse safety.

[0105] The closed-loop control system of baffle, guide rail, intelligent lifting, and water flow sensor in this embodiment can automatically adjust the baffle opening according to the real-time flow rate, realizing "fast drainage of large amounts of water and slow flow of small amounts of water", ensuring drainage safety in extreme weather conditions and enhancing purification in normal times.

[0106] Furthermore, the baffle includes a fully open state and a semi-closed state. In the fully open state, the baffle is lowered to the bottom of the ditch, allowing water to flow freely at a velocity of 0.3 m / s. In the semi-closed state, the baffle is raised to half the depth of the ditch, obstructing the water flow and forming a slow-flow zone at a velocity of 0.1 m / s.

[0107] Specifically, a comparison of water flow patterns under different baffle opening degrees:

[0108] Fully open: The baffle is lowered to the bottom of the ditch, allowing water to flow freely at a velocity of 0.3 m / s.

[0109] Semi-closed state: The baffle is raised to 1 / 2 of the ditch depth, the water flow is obstructed and a slow flow zone is formed, at which time the flow velocity is 0.1m / s.

[0110] Furthermore, this embodiment directly controls the hydraulic residence time by using two typical operating conditions: a fully open baffle with a flow velocity of 0.3 m / s and a semi-closed baffle with a flow velocity of 0.1 m / s. This balances the needs of drainage and purification without requiring manual intervention.

[0111] Furthermore, the water quality monitoring module includes a water quality sensor and a data transmission unit;

[0112] Water quality sensors are used to monitor effluent water quality parameters in real time;

[0113] The data transmission unit is used to transmit monitoring data to the remote monitoring center.

[0114] Furthermore, this embodiment constructs an "edge-cloud" architecture: the edge layer employs a low-power (standby ≤50 μA) multi-parameter sensor, with a built-in self-cleaning brush on the electrode that rotates once every 6 hours to prevent biofilm adhesion; NH4 + -N employs an ion-selective electrode and a temperature compensation algorithm, with a measurement error ≤ ±3%; NO3 --N employs UV spectroscopy, requiring no reagents and with a maintenance cycle of 90 days; COD is measured using 450 nm LED color compensation, resisting interference from suspended matter. Edge computing nodes utilize a LoRa self-organizing network with a single-hop distance >500m, capable of covering typical farmland grids; data is locally cached for 7 days, supporting breakpoint resume. The cloud platform integrates a "digital twin" model, automatically correcting hydraulic-water quality coupling parameters based on real-time data, predicting effluent water quality 7 days later, and providing early warnings.

[0115] The user-side WeChat mini-program allows users to view real-time curves, receive over-limit alarms, and remotely control the baffle opening. It is low-cost and low-power, meeting the needs of large-scale deployment in Datian.

[0116] In this embodiment, water quality sensors and data transmission units are deployed at the water outlet to acquire key indicators such as COD, TN, and TP in the effluent in real time, providing a data interface for remote diagnosis, maintenance reminders, and regional non-point source pollution monitoring.

[0117] Furthermore, the water quality monitoring module monitors water quality parameters including the concentrations of nitrogen, phosphorus, suspended solids, and pesticide residues.

[0118] This embodiment adopts a modular design, which can be directly embedded into existing irrigation canals, supports decentralized deployment, and is adaptable to large fields, irregular fields, and undulating terrain. It achieves "drainage and purification at the same time", promotes the use of land acquisition and does not require changes to the irrigation and drainage system. Maintenance only requires periodic harvesting of plants and inspection of the baffles. Under the premise of maintaining the drainage function of farmland, it achieves the goal of "zero land occupation, low cost, easy maintenance, and high efficiency" of ecological purification of farmland tailwater.

[0119] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A three-sided light ditch ecological purification upgrading system for farmland tail water treatment in the One Health perspective, characterized in that, The system comprises: a trench body; a stepped filler layer arranged along the side wall of the trench body; a plant community planted on the filler layer; a water flow regulating device arranged in the trench body; and a water quality monitoring module arranged at the water outlet of the trench body. The filler layer comprises, from bottom to top, a gravel layer, a biochar layer and a zeolite layer. The water flow regulating device comprises a baffle, a guide rail, an intelligent lifting mechanism and a water flow sensor. The baffle slides up and down along the guide rail, the water flow sensor is installed in the middle of the baffle, and the intelligent lifting mechanism is connected with the baffle and the water flow sensor respectively. The plant community is planted on the filler layer according to the height of the plants from high to low. The water quality monitoring module is used to monitor the water quality of the effluent. The system purifies the tail water of farmland through physical filtration, adsorption, microbial degradation and plant absorption of the filler layer.

2. The system of claim 1, wherein: the trench body is made of hard material; the trench body has an inverted isosceles trapezoidal structure; the hard material includes concrete or resin-based composite material; the bottom and two side surfaces of the trench body are hard structures, and the top is an open space.

3. The system of claim 1, wherein: the filler layer is symmetrically arranged along the side wall of the trench body; each level of the stepped filler layer has a height of 20-30 cm; the gravel layer, the biochar layer and the zeolite layer are respectively laid on different height levels of the stepped filler layer.

4. The system of claim 1, wherein: the particle size of the gravel layer is 5-10 cm; the particle size of the biochar layer is 2-5 cm; the particle size of the zeolite layer is 1-3 cm; the thickness of the gravel layer, the biochar layer and the zeolite layer is 30 cm, 20 cm and 30 cm respectively.

5. The system of claim 1, wherein: the gravel layer, the biochar layer and the zeolite layer are respectively filled with irregular point pattern, diagonal grid pattern and dense point pattern.

6. The system of claim 1, wherein: the plant community includes submerged plants, emergent plants and floating leaf plants; the submerged plants include Potamogeton crispus, Hydrilla verticillata, Vallisneria natans, Eichhornia crassipes, Myriophyllum spicatum and Ceratophyllum demersum; the emergent plants include Canna glauca, Iris and Lythrum salicaria.

7. The system of claim 1, wherein: the baffle of the water flow regulating device slides up and down along the guide rail through the intelligent lifting mechanism, for adjusting the opening degree of the baffle; the water flow sensor is used to monitor the water flow state in real time and transmit signals to the intelligent lifting mechanism; the intelligent lifting mechanism controls the lifting height of the baffle according to the signals of the water flow sensor.

8. The system of claim 1, wherein: the baffle includes a fully open state and a half-closed state, in the fully open state, the baffle is lowered to the bottom of the trench, the water flow is smooth, and the flow rate is 0.3 m / s; in the half-closed state, the baffle is lifted to half the depth of the trench, the water flow is blocked to form a slow flow area, and the flow rate is 0.1 m / s.

9. The system of claim 1, wherein: The water quality monitoring module comprises a water quality sensor and a data transmission unit; The water quality sensor is used for monitoring water quality parameters in real time; The data transmission unit is used for transmitting monitoring data to a remote monitoring center.

10. The system of claim 1, wherein The water quality parameters monitored by the water quality monitoring module include the concentrations of nitrogen, phosphorus, suspended solids, and pesticide residues.

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