Rural river reach water bank synchronous ecological comprehensive treatment system

Abstract

The invention discloses a rural river reach water bank synchronous ecological comprehensive treatment system. According to the invention, multiple layers of filter materials in the system are like multiple layers of'filter screens', zeolite at the bottom layer, charcoal particles at the middle layer and quartz sand at the surface layer have respective functions, some are responsible for adsorbing nitrogen and phosphorus pollutants, and some are helpful for microorganisms to attach and degrade organic matters. The filter materials and microorganisms work together, ammonia nitrogen and total phosphorus in water can be treated more thoroughly, finally, the water flowing out is cleaner, the content of the ammonia nitrogen and the content of the total phosphorus are controlled to be very low, and the water quality requirement of rural rivers can be better met. Reeds and water lilies are planted in the modularized planting grooves in the system, and root systems of the reeds and the water lilies grow in a staggered mode like a'protection net 'is woven for the river bank. In addition, the soil structure of the river bank can be tighter through water flow scouring of the tidal flow guide channel. The two aspects act together, the anti-shearing capacity of the river bank is obviously improved, the problems of collapse and landslide are not prone to occurring, and farmlands and villages on the two sides of the river channel can be protected for a longer time.

Description

Technical Field

[0001] This invention belongs to the field of river ecological restoration and bank protection engineering technology, specifically a rural river section water and bank synchronous ecological integrated treatment system. Background Technology

[0002] In current rural river management, ecological bank protection technology is gradually replacing traditional hard bank protection and becoming the mainstream development direction. Ecological bank protection technology achieves the dual goals of water purification and shoreline stability by simulating the natural riverbank structure and combining the synergistic effects of plants, microorganisms, and filter media. However, existing technologies generally suffer from low purification efficiency, insufficient erosion resistance, and reliance on manual maintenance, making it difficult to meet the needs of low-cost, high-efficiency management of rural river sections. In recent years, with the advancement of ecological restoration technologies, technologies such as vertical flow filters and plant root soil stabilization have been widely used, but how to achieve synergistic optimization of multiple technologies remains a technical challenge.

[0003] Existing technologies commonly include single-media bank revetment, single-vegetation bank revetment, and mechanical aeration bank revetment. Single-media bank revetment typically uses sand or zeolite as filter media, which can adsorb some pollutants, but its purification efficiency is limited and it is prone to clogging. Single-vegetation bank revetment stabilizes the soil by planting reeds or cattails, but its root system is singular and lacks erosion resistance. Mechanical aeration bank revetment promotes microbial degradation through continuous aeration, but it is energy-intensive and relies on manual maintenance. Each of these solutions has obvious limitations, making it difficult to balance purification effectiveness, stability, and economy.

[0004] However, the main drawbacks of existing technologies include: simple filter media structure and low pollutant removal efficiency; unreasonable plant configuration and insufficient shear strength of the bank slope; high energy consumption of aeration devices and high operation and maintenance costs; lack of natural hydraulic drive mechanism and reliance on external energy input. Summary of the Invention

[0005] The purpose of this invention is to provide a rural river section water-bank integrated ecological treatment system in order to solve the problems mentioned above.

[0006] The technical solution adopted in this invention is as follows: a rural river section waterfront synchronous ecological integrated treatment system, including a vertical flow composite filter bed structure, a modular planting trough unit, an intermittent microporous aeration device, and a tidal flow guiding channel; The vertical flow composite filter bed structure consists of a bottom zeolite layer, a middle charcoal particle layer, and a surface quartz sand layer. The modular planting trough units are arranged in a staggered 30° pattern, and reeds and water lilies are mixed in the troughs; The intermittent microporous aeration device releases air bubbles through a PVC perforated pipe placed at the bottom of the filter bed. The tidal flow diversion channel has a water storage chamber on the backwater side of the revetment, with a volume ratio of 1:3.

[0007] In a preferred embodiment, the zeolite layer has a particle size of 20-40 mm, the charcoal particle layer has a particle size of 5-10 mm, and the quartz sand layer has a particle size of 2-5 mm; the PVC perforated pipe has a pore size of 2 mm and a spacing of 50 cm.

[0008] In a preferred embodiment, the zeolite layer comprises: 65 parts by weight of zeolite (20-40 mm particle size, mainly clinoptilolite), 12 parts by weight of sepiolite particles (15-25 mm particle size), 8 parts by weight of apatite fragments (10-20 mm particle size), 7 parts by weight of expanded vermiculite (5-10 mm particle size), 5 parts by weight of nano-zero ferric iron coated zeolite (3-5 mm particle size), and 3 parts by weight of diatomaceous earth-chitosan composite microspheres (0.5-1 mm particle size).

[0009] Design Description: The filter bed is mainly composed of clinoptilolite (65%), which is used to adsorb nitrogen pollutants by utilizing its high ammonium ion exchange capacity; sepiolite (12%) is added to enhance the selective adsorption of heavy metals (such as lead and cadmium); apatite (8%) slowly releases phosphates, providing nutrients for microorganisms and neutralizing the alkalinity of the filter bed; expanded vermiculite (7%) has a porous structure that improves the water retention and air permeability of the filter bed; nano-zero-valent iron-coated zeolite (5%) degrades nitrates through redox reactions; diatomaceous earth-chitosan microspheres (3%) combine the adsorption properties of diatomaceous earth with the flocculation properties of chitosan to intercept suspended solids and reduce filter bed clogging.

[0010] In a preferred embodiment, the charcoal particle layer comprises: 50 parts by weight of fruitwood charcoal (5-10 mm particle size, mainly lychee charcoal), 20 parts by weight of bamboo charcoal (6-8 mm particle size, carbonized bamboo chips), 15 parts by weight of coconut shell activated carbon (7-9 mm particle size, acid-washed and activated), 8 parts by weight of activated carbon fiber balls (4-6 mm particle size), 3 parts by weight of shell powder (2-4 mm particle size), 2 parts by weight of humus particles (1-3 mm particle size), and 2 parts by weight of magnetic biochar (0.5-1 mm particle size).

[0011] Design Description: Lychee wood charcoal (50%) has uniform pores, enriching heterotrophic microorganisms to degrade organic matter; bamboo charcoal (20%) has well-developed micropores, adsorbing small molecule organic matter (such as phenol); acid-washed coconut shell activated carbon (15%) removes odors and enhances the adsorption of chlorinated hydrocarbons; activated carbon fiber balls (8%) have a high specific surface area to promote microbial biofilm formation; shell powder (3%) slowly releases calcium ions to regulate pH and prevent filter layer acidification; humic granules (2%) provide carbon source and trace elements to maintain microbial activity; magnetic biochar (2%) promotes microbial aggregation through magnetic effects, forming a highly efficient degradation colony.

[0012] In a preferred embodiment, the surface quartz sand layer comprises: 60 parts by weight of refined quartz sand (2-5 mm particle size, round quartz), 18 parts by weight of anthracite filter media (3-6 mm particle size, low volatile matter), 10 parts by weight of ceramsite sand (4-7 mm particle size, shale ceramsite), 7 parts by weight of fiber ball filter media (3-5 mm particle size, polypropylene fiber), 3 parts by weight of zeolite micro powder (0.5-1 mm particle size, ammonium saturated pretreated), 1 part by weight of nano-TiO2 loaded sand (0.3-0.8 mm particle size), and 1 part by weight of chitosan modified clay (0.2-0.5 mm particle size).

[0013] Design Description: Round-grained quartz sand (60%) has a smooth surface, reducing the adhesion of suspended solids and extending the backwashing cycle; Anthracite (18%) has a low density, forming a "light on top, heavy on bottom" gradation with quartz sand, improving filtration depth; Shale ceramsite (10%) has a porous structure that intercepts colloidal particles; Polypropylene fiber balls (7%) have good elasticity and are compressible, enhancing the capture of fine suspended solids; Ammonium-saturated zeolite micro powder (3%) releases ammonium ions to induce the aggregation of nitrifying bacteria; Nano-TiO2-loaded sand (1%) photocatalytically degrades organic matter (such as pesticide residues) under light; Chitosan-modified clay (1%) neutralizes flocculants by charge, reducing the risk of filter clogging.

[0014] In a preferred embodiment, the modular planting trough unit adopts a detachable composite material trough body, the main body of which is made of high-density polyethylene (HDPE) frame and bamboo fiber reinforced board, combining corrosion resistance, lightweight and eco-friendliness. The bottom of the trough has "honeycomb-shaped permeation holes" (pore diameter 5-8mm, spacing 10cm), which allows plant roots to penetrate to the deep layer of the filter bed and also allows for regulation of the water depth in the trough (maintaining a water level of 0-15cm to accommodate the different water requirements of reeds and water lilies). The trough edge is designed with a "tie-and-mortise connection structure," with adjacent troughs fixed by a 30° staggered interlocking joint, forming a continuous revegetation belt that resists water erosion and facilitates later replacement of individual troughs or replanting of plants.

[0015] In a preferred embodiment, the modular planting trough unit employs a "vertical layering + functional complementarity" plant configuration: Reeds are emergent aquatic plants, 1.5–2.0 m tall, with well-developed fibrous roots (60–80 cm long taproot) that can penetrate the quartz sand layer, charcoal particle layer, and even the zeolite layer. The organic acids secreted by the roots dissolve pollutant adsorption products (such as phosphate precipitates) on the filter media surface, while simultaneously providing an aerobic microenvironment for nitrifying bacteria. Water lilies are floating-leaved plants, 20–30 cm in diameter, with horizontal roots (lateral roots extending 50–70 cm) mainly distributed on the surface of the quartz sand layer. The mucus secreted by the root hairs encapsulates suspended matter, forming a "biofilter membrane" that intercepts particulate pollutants. The interwoven root systems of the two plants form a "three-dimensional purification network," increasing the pollutant removal rate on the filter bed surface by 30%–40%.

[0016] In a preferred embodiment, the internal structure of the intermittent microporous aeration device includes: The filter bed uses gradient-pore-size PVC perforated pipes. The main pipe diameter is 50mm, arranged in a serpentine pattern along the bottom of the filter bed (below the zeolite layer). The branch pipes are spaced 80cm apart, and each branch pipe has two rows of micropores: 2mm diameter micropores near the center of the filter bed (50cm spacing) and 1.5mm diameter micropores at the edge (40cm spacing). This gradient design ensures uniform bubble distribution (1-3mm diameter, covering 95% of the filter bed area). Aeration employs "time-sequence intelligent control," using water quality sensors (installed on the surface and bottom of the filter bed) to monitor dissolved oxygen (DO) and ammonia nitrogen (NH4⁺-N) concentrations in real time. When DO < 2mg / L or NH4⁺-N > 5mg / L at the bottom, aeration is automatically initiated (lasting 30 minutes each time, with a 2-hour interval). This avoids excessive aeration that could disturb the filter media while precisely meeting the oxygen requirements of the nitrification reaction.

[0017] The aeration process drives the internal water circulation of the filter bed through the "airlift effect": as air bubbles rise, they carry the bottom water (containing high concentrations of ammonia nitrogen) upwards, forming a "microenvironment gradient" with the denitrifying bacteria (anaerobic environment) in the middle charcoal granule layer and the aerobic bacteria in the surface quartz sand layer, promoting simultaneous nitrification-denitrification reactions. Simultaneously, the slight disturbance of the filter media by the air bubbles can peel off the aged biofilm on the filter media surface, preventing filter clogging (extending the backwashing cycle to 6-8 months). Actual measurements show that this device can maintain a stable ammonia nitrogen removal rate of over 85% and a total nitrogen removal rate of 60%–65%.

[0018] In a preferred embodiment, the tidal flow diversion channel is arranged in a "stepped" manner along the backwater surface (land side) of the revetment. The main body is composed of a precast concrete trough (1.2m wide and 1.0m deep) and an ecological gabion (filled with 30-50mm gravel). The bottom slope of the trough is 1‰ to ensure slow water flow. The water storage chamber at the end of the channel adopts a "dual-chamber separation design" - the main chamber (75% of the volume) is used to store filter bed infiltration water during high tide, and the secondary chamber (25% of the volume) is connected to the main chamber through an overflow pipe, which can adjust the maximum water level (the water level difference between the main chamber and the river channel is ≤30cm) to avoid waterlogging in the revetment.

[0019] The tidal circulation mechanism is achieved through a combination of natural water level fluctuations and artificial assistance: During daily river level fluctuations (range 0.5–1.0 m), water flows through the permeable wall into the bottom layer of the filter bed (zeolite layer), then ascends through each filter media layer and overflows from the surface into the main cavity of the guide channel. When the river recedes, the water in the main cavity flows back into the river through the overflow pipe in the secondary cavity, forming an "upward-downward" cycle (2–3 cycles per day). This process not only replenishes the filter bed with dissolved oxygen (top-layer DO can reach 5–6 mg / L), but also inhibits the excessive proliferation of anaerobic microorganisms (such as sulfate-reducing bacteria) and reduces the production of odorous gases such as hydrogen sulfide through periodic wet-dry alternation (the filter bed surface is wet for 60%–70% of the time). Operational testing has shown that this guide channel can increase the filter bed's COD (chemical oxygen demand) removal rate by 20%–25% while reducing maintenance costs by 30%.

[0020] In a preferred embodiment, the tidal flow channel is connected to the filter bed by a "vertical permeable wall" (composed of a 50cm thick gravel layer and a 30cm thick geotextile), which allows for free water exchange while preventing the loss of filter media.

[0021] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this invention, the multi-layered filter media in the system act like a multi-layered "filter net." The bottom layer of zeolite, the middle layer of charcoal particles, and the top layer of quartz sand each have their own functions. Some are responsible for adsorbing nitrogen and phosphorus pollutants, while others help microorganisms attach and degrade organic matter. These filter media work together with microorganisms to more thoroughly treat ammonia nitrogen and total phosphorus in the water, resulting in cleaner water with very low levels of ammonia nitrogen and total phosphorus, better meeting the water quality requirements of rural rivers. The modular planting troughs in the system are planted with reeds and water lilies, whose intertwined root systems act like a "protective net" for the riverbank. Combined with the scouring effect of the tidal flow channel, the soil structure of the riverbank becomes more compact. With both of these working together, the shear resistance of the riverbank is significantly enhanced, making it less prone to collapse and landslides, thus protecting the farmland and villages on both sides of the river for a longer period.

[0022] 2. In this invention, the system fully utilizes natural hydraulic changes, such as the rise and fall of river water levels, to drive water circulation, reducing the need for additional power equipment. Simultaneously, the intermittent microporous aeration device operates during off-peak electricity hours, further saving on electricity costs. Combined, these two aspects result in very low annual maintenance costs per kilometer of river channel, reducing economic burden on rural areas and making long-term adoption easier.

[0023] 3. In this invention, the zeolite in the zeolite layer primarily adsorbs ammonia nitrogen from the water. Bio-ceramic particles provide more space for microorganisms to "settle down," allowing them to better degrade pollutants. Nano-iron oxides help adsorb phosphorus, volcanic rock slowly releases minerals to keep microorganisms active, and diatomaceous earth fills the pores, improving the filter layer's permeability and trapping some suspended solids. The charcoal layer, composed of fruitwood charcoal, bamboo charcoal, and coconut shell charcoal, each has its own strengths—fruitwood charcoal's numerous pores can "nurture" more microorganisms to degrade organic matter, bamboo charcoal's fine pores can adsorb smaller organic molecules, coconut shell charcoal is hard and not easily broken, polyethylene balls provide more attachment sites for microorganisms, and limestone slowly releases calcium to neutralize acidity, making microorganisms more active. The surface layers of quartz sand and anthracite act like "coarse and fine sieves," first trapping large suspended particles, then zeolite micropowder adsorbs dissolved ammonia nitrogen, and finally, biochar absorbs dissolved organic matter. These three layers of filter media work together to purify the water more thoroughly, make the filter media more durable, and ensure more stable system operation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention.

[0025] The diagram shows: 1 - Vertical flow composite filter bed structure, 2 - Modular planting trough unit, 3 - Intermittent microporous aeration device, and 4 - Tidal flow guide channel. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] Example: Reference Figure 1 , A rural riverbank integrated ecological treatment system includes a vertical flow composite filter bed structure 1, a modular planting trough unit 2, an intermittent microporous aeration device 3, and a tidal flow guiding channel 4; The vertical flow composite filter bed structure 1 consists of a bottom zeolite layer with a thickness of 50cm, a middle charcoal particle layer with a thickness of 30cm, and a surface quartz sand layer with a thickness of 20cm. Modular planting trough units 2 are arranged in a staggered 30° pattern, with reeds and water lilies mixed in the troughs; The intermittent microporous aeration device 3 releases air bubbles through a PVC perforated pipe placed at the bottom of the filter bed; Tidal flow diversion channel 4 has a water storage chamber on the backwater side of the revetment, with a volume ratio of 1:3.

[0028] The zeolite layer has a particle size of 20–40 mm, the charcoal particle layer has a particle size of 5–10 mm, and the quartz sand layer has a particle size of 2–5 mm; the PVC perforated pipe has a hole diameter of 2 mm and a spacing of 50 cm.

[0029] The zeolite layer includes: 65 parts by weight of zeolite (20-40 mm particle size, mainly clinoptilolite), 12 parts by weight of sepiolite particles (15-25 mm particle size), 8 parts by weight of apatite fragments (10-20 mm particle size), 7 parts by weight of expanded vermiculite (5-10 mm particle size), 5 parts by weight of nano-zero ferric iron coated zeolite (3-5 mm particle size), and 3 parts by weight of diatomaceous earth-chitosan composite microspheres (0.5-1 mm particle size).

[0030] Design Description: The filter bed is mainly composed of clinoptilolite (65%), which is used to adsorb nitrogen pollutants by utilizing its high ammonium ion exchange capacity; sepiolite (12%) is added to enhance the selective adsorption of heavy metals (such as lead and cadmium); apatite (8%) slowly releases phosphates, providing nutrients for microorganisms and neutralizing the alkalinity of the filter bed; expanded vermiculite (7%) has a porous structure that improves the water retention and air permeability of the filter bed; nano-zero-valent iron-coated zeolite (5%) degrades nitrates through redox reactions; diatomaceous earth-chitosan microspheres (3%) combine the adsorption properties of diatomaceous earth with the flocculation properties of chitosan to intercept suspended solids and reduce filter bed clogging.

[0031] The charcoal pellet layer includes: 50 parts by weight of fruitwood charcoal (5-10 mm particle size, mainly lychee wood charcoal), 20 parts by weight of bamboo charcoal (6-8 mm particle size, carbonized bamboo chips), 15 parts by weight of coconut shell activated carbon (7-9 mm particle size, acid-washed and activated), 8 parts by weight of activated carbon fiber balls (4-6 mm particle size), 3 parts by weight of shell powder (2-4 mm particle size), 2 parts by weight of humus granules (1-3 mm particle size), and 2 parts by weight of magnetic biochar (0.5-1 mm particle size).

[0032] Design Description: Lychee wood charcoal (50%) has uniform pores, enriching heterotrophic microorganisms to degrade organic matter; bamboo charcoal (20%) has well-developed micropores, adsorbing small molecule organic matter (such as phenol); acid-washed coconut shell activated carbon (15%) removes odors and enhances the adsorption of chlorinated hydrocarbons; activated carbon fiber balls (8%) have a high specific surface area to promote microbial biofilm formation; shell powder (3%) slowly releases calcium ions to regulate pH and prevent filter layer acidification; humic granules (2%) provide carbon source and trace elements to maintain microbial activity; magnetic biochar (2%) promotes microbial aggregation through magnetic effects, forming a highly efficient degradation colony.

[0033] The surface quartz sand layer includes: 60 parts by weight of refined quartz sand (2-5 mm particle size, round quartz), 18 parts by weight of anthracite filter media (3-6 mm particle size, low volatile matter), 10 parts by weight of ceramsite sand (4-7 mm particle size, shale ceramsite), 7 parts by weight of fiber ball filter media (3-5 mm particle size, polypropylene fiber), 3 parts by weight of zeolite micro powder (0.5-1 mm particle size, ammonium saturated pretreated), 1 part by weight of nano-TiO2 loaded sand (0.3-0.8 mm particle size), and 1 part by weight of chitosan modified clay (0.2-0.5 mm particle size).

[0034] Design Description: Round-grained quartz sand (60%) has a smooth surface, reducing the adhesion of suspended solids and extending the backwashing cycle; Anthracite (18%) has a low density, forming a "light on top, heavy on bottom" gradation with quartz sand, improving filtration depth; Shale ceramsite (10%) has a porous structure that intercepts colloidal particles; Polypropylene fiber balls (7%) have good elasticity and are compressible, enhancing the capture of fine suspended solids; Ammonium-saturated zeolite micro powder (3%) releases ammonium ions to induce the aggregation of nitrifying bacteria; Nano-TiO2-loaded sand (1%) photocatalytically degrades organic matter (such as pesticide residues) under light; Chitosan-modified clay (1%) neutralizes flocculants by charge, reducing the risk of filter clogging.

[0035] Modular planting trough unit 2 uses a detachable composite material trough. The main body is made of a high-density polyethylene (HDPE) frame and bamboo fiber reinforced board, which combines corrosion resistance, lightweight, and eco-friendliness. The bottom of the trough has honeycomb-shaped permeation holes (5-8mm in diameter, spaced 10cm apart), allowing plant roots to penetrate deep into the filter bed and regulating the water depth within the trough (maintaining a water level of 0-15cm to accommodate the different water requirements of reeds and water lilies). The trough edges are designed with a "tie-and-mortise connection structure," where adjacent troughs are fixed together at a 30° staggered angle, forming a continuous revegetation strip that resists water erosion and facilitates later replacement of individual troughs or replanting.

[0036] The modular planting trough unit 2 employs a "vertical layering + functional complementarity" plant configuration: Reeds, emergent plants with a height of 1.5–2.0m, have extensive fibrous root systems (60–80cm long taproots) that can penetrate the quartz sand layer, charcoal particle layer, and even the zeolite layer. The organic acids secreted by the roots dissolve pollutant adsorption products (such as phosphate precipitates) on the filter media surface, while simultaneously providing an aerobic microenvironment for nitrifying bacteria. Water lilies, floating-leaved plants with leaf diameters of 20–30cm, have horizontal root systems (lateral roots extending 50–70cm) mainly distributed on the surface of the quartz sand layer. The mucus secreted by the root hairs encapsulates suspended matter, forming a "biofilter membrane" that intercepts particulate pollutants. The interwoven root systems of the two plants form a "three-dimensional purification network," increasing the pollutant removal rate on the filter bed surface by 30%–40%.

[0037] The intermittent microporous aeration device (3) is internally equipped with: The filter bed uses gradient-pore-size PVC perforated pipes. The main pipe diameter is 50mm, arranged in a serpentine pattern along the bottom of the filter bed (below the zeolite layer). The branch pipes are spaced 80cm apart, and each branch pipe has two rows of micropores: 2mm diameter micropores near the center of the filter bed (50cm spacing) and 1.5mm diameter micropores at the edge (40cm spacing). This gradient design ensures uniform bubble distribution (1-3mm diameter, covering 95% of the filter bed area). Aeration employs "time-sequence intelligent control," using water quality sensors (installed on the surface and bottom of the filter bed) to monitor dissolved oxygen (DO) and ammonia nitrogen (NH4⁺-N) concentrations in real time. When DO < 2mg / L or NH4⁺-N > 5mg / L at the bottom, aeration is automatically initiated (lasting 30 minutes each time, with a 2-hour interval). This avoids excessive aeration that could disturb the filter media while precisely meeting the oxygen requirements of the nitrification reaction.

[0038] The aeration process drives the internal water circulation of the filter bed through the "airlift effect": as air bubbles rise, they carry the bottom water (containing high concentrations of ammonia nitrogen) upwards, forming a "microenvironment gradient" with the denitrifying bacteria (anaerobic environment) in the middle charcoal granule layer and the aerobic bacteria in the surface quartz sand layer, promoting simultaneous nitrification-denitrification reactions. Simultaneously, the slight disturbance of the filter media by the air bubbles can peel off the aged biofilm on the filter media surface, preventing filter clogging (extending the backwashing cycle to 6-8 months). Actual measurements show that this device can maintain a stable ammonia nitrogen removal rate of over 85% and a total nitrogen removal rate of 60%–65%.

[0039] The tidal flow diversion channel 4 is arranged in a "stepped" manner along the backwater side (land side) of the revetment. The main body is composed of a precast concrete trough (1.2m wide and 1.0m deep) and an ecological gabion (filled with 30-50mm gravel). The bottom slope of the trough is 1‰ to ensure slow water flow. The water storage chamber at the end of the channel adopts a "dual-chamber separation design" - the main chamber (75% of the volume) is used to store filter bed infiltration water during high tide, and the secondary chamber (25% of the volume) is connected to the main chamber through an overflow pipe, which can adjust the maximum water level (the water level difference between the main chamber and the river channel is ≤30cm) to avoid waterlogging in the revetment.

[0040] The tidal flow circulation mechanism is achieved through a combination of natural water level fluctuations and artificial assistance: During daily river water level fluctuations (range 0.5–1.0 m), water flows through the permeable wall into the bottom layer of the filter bed (zeolite layer), then ascends through each filter media layer and overflows from the surface into the main cavity of the guide channel. When the river recedes, the water in the main cavity flows back into the river through the overflow pipe in the secondary cavity, forming an "upward-downward" cycle (2–3 cycles per day). This process not only replenishes the filter bed with dissolved oxygen (top-layer DO can reach 5–6 mg / L), but also inhibits the excessive proliferation of anaerobic microorganisms (such as sulfate-reducing bacteria) and reduces the production of odorous gases such as hydrogen sulfide through periodic wet-dry alternation (the filter bed surface is wet for 60%–70% of the time). Operational testing has shown that this guide channel can increase the COD (chemical oxygen demand) removal rate of the filter bed by 20%–25%, while reducing maintenance costs by 30%. The tidal flow channel 4 is connected to the filter bed by a "vertical permeable wall" (composed of a 50cm thick gravel layer + a 30cm thick geotextile), which allows for free water exchange while preventing the loss of filter media.

[0041] The above-mentioned operating steps and precautions include: S1: Construct a vertical flow composite filter bed structure, with a bottom layer of 20-40mm zeolite (50cm thick), a middle layer of 5-10mm charcoal particles (30cm thick), and a top layer of 2-5mm quartz sand (20cm thick). The zeolite layer adsorbs ammonium nitrogen through ion exchange, the charcoal layer enriches organic matter degraded by microorganisms, and the sand layer filters suspended solids.

[0042] S2: Modular planting troughs are used, with each unit arranged at a 30° staggered angle. Reeds (30cm spacing) and water lilies (40% coverage) are mixed within the troughs. The reed roots penetrate deep into the filter bed to stabilize the soil, while the water lily roots form a surface network structure. The two plants work together to inhibit soil erosion. A tidal flow channel is designed, and a water storage chamber (1:3 volume ratio) is set on the backwater side of the revetment. The daily natural rise and fall of the water level drives the water to complete an upward and downward circulation within the filter bed, achieving a daily water circulation volume of 1.5 times the river flow rate without the need for external power.

[0043] S3: Equipped with an intermittent microporous aeration device, which is activated only during off-peak hours at night. It releases air bubbles through PVC perforated pipes (2mm pore size, 50cm spacing) placed at the bottom of the filter bed to promote aerobic microbial activity, with energy consumption controlled at 0.5kW·h / day.

[0044] From the above, we can conclude that: In this invention, the multi-layered filter media in the system act like a multi-layered "filter net." The bottom layer of zeolite, the middle layer of charcoal particles, and the top layer of quartz sand each have their own functions: some adsorb nitrogen and phosphorus pollutants, while others help microorganisms attach and degrade organic matter. These filter media, working together with microorganisms, can more thoroughly treat ammonia nitrogen and total phosphorus in the water, resulting in cleaner water with significantly lower levels of both, better meeting the water quality requirements of rural waterways. The modular planting troughs in the system are planted with reeds and water lilies, whose intertwined root systems act like a "protective net" for the riverbank. Combined with the scouring effect of the tidal flow channel, this makes the riverbank soil structure more compact. These two factors work together to significantly enhance the shear resistance of the riverbank, making it less prone to collapse and landslides, and providing longer-lasting protection for the farmland and villages on both sides of the river.

[0045] In this invention, the system fully utilizes natural hydraulic changes, such as the rise and fall of river water levels, to drive water circulation, reducing the need for additional power equipment. Simultaneously, the intermittent microporous aeration device operates during off-peak electricity hours, further saving on electricity costs. Combined, these two aspects result in very low annual maintenance costs per kilometer of river channel, reducing the economic burden on rural areas and making long-term adoption easier.

[0046] In this invention, the zeolite in the zeolite layer primarily adsorbs ammonia nitrogen from the water, while bio-ceramic particles provide more space for microorganisms to "settle down," allowing them to better degrade pollutants. Nano-iron oxides help adsorb phosphorus, volcanic rock slowly releases minerals to keep microorganisms active, and diatomaceous earth fills the pores, improving the filter layer's permeability and trapping some suspended solids. The charcoal layer, composed of fruitwood charcoal, bamboo charcoal, and coconut shell charcoal, each has its own strengths—fruitwood charcoal's numerous pores can "nurture" more microorganisms to degrade organic matter, bamboo charcoal's fine pores can adsorb smaller organic molecules, coconut shell charcoal is hard and not easily broken, polyethylene balls provide more attachment sites for microorganisms, and limestone slowly releases calcium to neutralize acidity, making microorganisms more active. The surface layers of quartz sand and anthracite act like "coarse and fine sieves," first trapping large suspended particles, then zeolite micropowder adsorbs dissolved ammonia nitrogen, and finally, biochar absorbs dissolved organic matter. With these three layers working together, the water is purified more thoroughly, the filter media is more durable, and the system operates more stably.

[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A comprehensive ecological treatment system for rural river sections, characterized in that: It includes a vertical flow composite filter bed structure (1), a modular planting trough unit (2), an intermittent microporous aeration device (3), and a tidal flow guiding channel (4). The vertical flow composite filter bed structure (1) consists of a bottom zeolite layer, a middle charcoal particle layer and a surface quartz sand layer; The modular planting trough units (2) are arranged in a staggered 30° pattern, and reeds and water lilies are mixed in the troughs; The intermittent microporous aeration device (3) releases air bubbles through a PVC perforated pipe placed at the bottom of the filter bed; The tidal flow diversion channel (4) has a water storage cavity on the backwater side of the revetment, with a volume ratio of 1:

3.

2. The integrated ecological treatment system for rural river sections with simultaneous water and bank management as described in claim 1, characterized in that: The zeolite layer has a particle size of 20–40 mm, the charcoal particle layer has a particle size of 5–10 mm, and the quartz sand layer has a particle size of 2–5 mm; the PVC perforated pipe has a hole diameter of 2 mm and a spacing of 50 cm.

3. The integrated ecological treatment system for rural river sections and banks as described in claim 1, characterized in that: The zeolite layer comprises: 65 parts by weight of zeolite, 12 parts by weight of sepiolite particles, 8 parts by weight of apatite fragments, 7 parts by weight of expanded vermiculite, 5 parts by weight of nano-zero-valent iron-coated zeolite, and 3 parts by weight of diatomaceous earth-chitosan composite microspheres.

4. The integrated ecological treatment system for rural river sections and banks as described in claim 1, characterized in that: The charcoal granule layer comprises: 50 parts by weight of fruitwood charcoal, 20 parts by weight of bamboo charcoal, 15 parts by weight of coconut shell activated carbon, 8 parts by weight of activated carbon fiber balls, 3 parts by weight of shell powder, 2 parts by weight of humus granules, and 2 parts by weight of magnetic biochar.

5. The integrated ecological treatment system for rural river sections with simultaneous water and bank management as described in claim 1, characterized in that: The surface quartz sand layer comprises: 60 parts by weight of refined quartz sand, 18 parts by weight of anthracite filter media, 10 parts by weight of ceramsite sand, 7 parts by weight of fiber ball filter media, 3 parts by weight of zeolite powder, 1 part by weight of nano-TiO2 loaded sand, and 1 part by weight of chitosan modified clay.

6. The integrated ecological treatment system for rural river sections and banks as described in claim 1, characterized in that: The modular planting trough unit (2) adopts a detachable composite material trough. The main body of the modular planting trough unit (2) is made of high-density polyethylene frame and bamboo fiber reinforced board. The bottom of the trough of the modular planting trough unit (2) is opened with "honeycomb-shaped permeation holes". The edge of the trough of the modular planting trough unit (2) is designed with "tie-joint connection structure". Adjacent troughs are fixed by 30° staggered interlocking to form a continuous bank protection vegetation belt.

7. The integrated ecological treatment system for rural river sections with simultaneous water and bank management as described in claim 1, characterized in that: The modular planting trough unit (2) adopts a vertical layering + functional complementarity mode for plant configuration: the interior of the modular planting trough unit (2) is planted with reeds, which are emergent aquatic plants with a plant height of 1.5 to 2.0m.

8. The integrated ecological treatment system for rural river sections with simultaneous water and bank management as described in claim 1, characterized in that: The intermittent microporous aeration device (3) is equipped with gradient pore diameter PVC perforated pipes. The main pipe of the perforated pipe has a diameter of 50mm and is arranged in a "snake-like" pattern along the bottom of the filter bed. The branch pipes are spaced 80cm apart, and each branch pipe has two rows of micropores: the micropores near the center of the filter bed have a diameter of 2mm, and the micropores at the edge have a diameter of 1.5mm.

9. A rural riverbank integrated ecological treatment system as described in claim 1, characterized in that: The tidal flow diversion channel (4) is arranged in a "stepped" manner along the backwater surface of the revetment. The main body of the tidal flow diversion channel (4) is composed of a precast concrete trough and an ecological gabion. The bottom slope of the trough is 1‰. The secondary cavity of the tidal flow diversion channel (4) is connected to the main cavity through an overflow pipe.

10. A rural riverbank integrated ecological treatment system as described in claim 1, characterized in that: The tidal flow channel (4) is connected to the filter bed via a "vertical permeation wall".

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