An ecological treatment process and structure for wastewater purification

Abstract

This application relates to an ecological treatment process and structure for effluent purification, belonging to the field of effluent purification technology. It includes: S1, ecological enhancement zone treatment, where effluent undergoes preliminary purification through a composite ecological filter bed, artificial aquatic plant purification belt, three-dimensional ecological floating bed, and pollution-tolerant plant purification belt; S2, ecological buffer zone treatment, where effluent from the ecological enhancement zone is introduced into the ecological buffer zone for secondary purification by submerged plants; S3, ecological demonstration zone treatment, where the effluent treated in the ecological buffer zone is introduced into the ecological demonstration zone for tertiary purification; S4, ecological stabilization zone treatment, where an aquatic plant community is constructed in the ecological stabilization zone, and zooplankton, benthic animals, and microorganisms are introduced to optimize the community, resulting in a fourth purification of the effluent. This application eliminates the need for fish, relying on microorganism-plant synergy for direct denitrification. Animals only assist in removing impurities, resulting in no additional nitrogen load and thus ensuring the stability of the purification system.

Description

Technical Field

[0001] This application relates to the field of wastewater purification technology, and in particular to an ecological treatment process and structure for wastewater purification. Background Technology

[0002] With urban development and construction, the scale of urban sewage treatment is gradually increasing. Considering environmental capacity, it is necessary to further treat the effluent from urban sewage treatment plants.

[0003] Invention publication number CN108793646B discloses a landscape-style ecological treatment system for domestic sewage. The specification states that the biological cultivation oxidation pond I, the biochemical cultivation oxidation pond II, and the decomposition pond all contain omnivorous fish (excluding silver carp) that feed on phytoplankton, such as snakehead, catfish, carp, crucian carp, silverfish, ornamental fish, and snails. The introduction of omnivorous fish (snakehead, carp, etc.) and filter-feeding fish (silver carp, bighead carp) indirectly affects the microbial community by consuming algae and plankton. In related prior art, fish excrement increases ammonia nitrogen load, interfering with denitrification efficiency. Furthermore, fish mortality leads to water quality deterioration, or excessive reproduction causes system collapse, resulting in poor stability of the effluent purification system. Summary of the Invention

[0004] To address the problem of water quality deterioration caused by fish deaths or system collapse due to overpopulation, resulting in poor stability of the wastewater purification system, this application provides an ecological wastewater purification process and structure.

[0005] The wastewater purification and ecological treatment process and structure provided in this application adopt the following technical solution:

[0006] An ecological treatment process for effluent purification includes the following steps: S1, ecological enhancement zone treatment: effluent is introduced into the ecological enhancement zone, where it undergoes preliminary purification by passing through a composite ecological filter bed, an artificial aquatic plant purification belt, a three-dimensional ecological floating bed, and a pollution-tolerant plant purification belt; S2, ecological buffer zone treatment: effluent from the ecological enhancement zone is introduced into the ecological buffer zone, where submerged plants in the buffer zone perform secondary purification. Submerged plants are planted in a ratio of *Vallisneria natans*: *Potamogeton pectinatus*: *Ceratophyllum demersum*: *Potamogeton malaianum*: *Potamogeton pectinatus* = 6:1:1:1:1; S3, ecological demonstration zone treatment: in the shallow water area of ​​the ecological demonstration zone, *Vallisneria natans*: *Potamogeton pectinatus*: *Potamogeton pectinatus* is planted in a ratio of 8:1:1, and in the deep water area, in a ratio of 1:6:3. The effluent treated in the ecological buffer zone is then introduced into the ecological demonstration zone for a third purification process. S4. Ecological stabilization zone treatment: Submerged plants, floating-leaved plants, and emergent plants are arranged in the ecological stabilization zone to construct an aquatic plant community. Zooplankton, benthic animals, and microorganisms are then introduced to optimize the community. The treated effluent from the ecological demonstration zone is then introduced into the ecological stabilization zone for four purification processes.

[0007] By adopting the above technical solutions, the effluent undergoes multi-stage treatment in an ecological enhancement zone, ecological buffer zone, ecological demonstration zone, and ecological stabilization zone, ultimately achieving highly efficient purification. In the ecological enhancement zone, a composite ecological filter bed removes pollutants through physical filtration, chemical adsorption, and biodegradation. An artificial aquatic plant purification belt provides a large specific surface area to promote microbial attachment, while a three-dimensional ecological floating bed and pollution-tolerant plant purification belt further reduce the pollution load. Subsequently, the ecological buffer zone uses a rationally proportioned mix of submerged plants for secondary purification of the effluent, effectively removing residual organic matter and nitrogen and phosphorus nutrients. Upon entering the ecological demonstration zone, the planting ratio is optimized according to different water conditions, balancing purification effectiveness with landscape requirements. Finally, in the ecological stabilization zone, various aquatic plants are comprehensively arranged, and zooplankton, benthic animals, and microorganisms are introduced to form a healthy ecosystem food chain, significantly improving the water body's self-purification capacity and stability, ensuring that the effluent meets the Class III water quality standard of the "Surface Water Environmental Quality Standard" (TN≤1.5mg / L). The proposed solution eliminates fish disturbance and relies on submerged plants (coverage ≥80%) and microbial communities to form a stable ecological barrier. Microorganisms and plants work together to directly remove nitrogen, while animals only assist in removing impurities, resulting in no additional nitrogen load and thus ensuring the stability of the purification system.

[0008] Preferably, the composite ecological filter bed includes a gravel bed, filter media, emergent plants, and aeration pipes, which remove nitrogen and phosphorus through the synergistic effect of physical filtration, chemical adsorption, and biofilm, wherein: the wastewater retention time is 1.3-1.7 hours; the filter media porosity is 70%-75%; the filtration rate is 0.5-0.7 m / h; and the aeration intensity is 18-22 L / (m²·s).

[0009] By adopting the above technical solution, a wastewater retention time of 1.3-1.7 hours was set to ensure sufficient reaction time for thorough pollutant removal. Furthermore, the filter media porosity was controlled at 70%-75%, ensuring both good filtration performance and appropriate permeability to prevent clogging. Simultaneously, a filtration rate of 0.5-0.7 m / h was designed to reduce energy consumption while maintaining treatment efficiency. Finally, an aeration intensity of 18-22 L / (m²·s) promoted the metabolic activity of aerobic microorganisms, improved nitrification efficiency, and ultimately achieved highly efficient nitrogen and phosphorus removal.

[0010] Preferably, the filter media has a porous structure, which allows microorganisms to attach to the filter media and form an aerobic zone and an anaerobic zone. The microorganisms undergo nitrification in the aerobic zone and denitrification in the anaerobic zone.

[0011] By adopting the above technical solution, the porous structure of the filter media significantly increases the surface area for microbial attachment, forming a rich biofilm. The biofilm naturally stratifies, with aerobic and anoxic zones coexisting, thus achieving simultaneous nitrification and denitrification processes. This design effectively improves nitrogen removal efficiency while simplifying the process, reducing energy consumption and operating costs, and ensuring stable effluent quality that meets standards.

[0012] Preferably, in the artificial aquatic plant purification strip, the artificial aquatic plants have a specific surface area ≥250m² / m², a tensile strength ≥10KN / m, and a laying density of 8-12 plants / m².

[0013] By adopting the above technical solutions, the artificial aquatic plants in the artificial aquatic plant purification zone have a large specific surface area, which can effectively adsorb pollutants in the water and improve purification efficiency. At the same time, the high tensile strength ensures the stability of the artificial aquatic plants under the impact of water flow and extends their service life. The reasonable laying density ensures sufficient purification capacity while avoiding maintenance difficulties caused by excessive density, thereby achieving effective removal of pollutants such as nitrogen and phosphorus from the effluent.

[0014] Preferably, the three-dimensional ecological floating bed includes an upper layer planted with irises and coin grass at a density of 9 clumps / m², and a lower layer with suspended artificial aquatic plants, 1.2-1.8m in length, accounting for 1.2-1.8 times the area of ​​the floating bed.

[0015] By adopting the above technical solution, the two-layer structure of the three-dimensional ecological floating bed can effectively enhance the water purification capacity. The upper layer is planted with irises and *Ipomoea aquatica* at a density of 9 clumps per square meter. These plants have strong root absorption and metabolic capabilities, efficiently removing nitrogen and phosphorus nutrients from the water while beautifying the aquatic landscape. The lower layer suspends artificial aquatic plants, ranging in length from 1.2 to 1.8 meters, covering an area 1.2 to 1.8 times the total area of ​​the floating bed. The artificial aquatic plants provide a large specific surface area, which is conducive to the formation and growth of microbial films, thereby further enhancing the adsorption and degradation of organic matter and suspended particles. This combined design not only improves pollutant removal efficiency but also enhances the stability and sustainability of the entire ecosystem.

[0016] Preferably, the pollution-resistant plant purification zone includes *Hydrilla verticillata*, *Myriophyllum spicatum*, *Ceratophyllum demersum*, and *Potamogeton crispus*, arranged at 72 plants per square meter.

[0017] By adopting the above technical solution, the pollution-resistant plant purification zone is composed of submerged plants such as Hydrilla verticillata, Myriophyllum spicatum, Ceratophyllum demersum, and Potamogeton crispus, and is arranged at a density of 72 plants / square meter. It can effectively absorb nitrogen and phosphorus nutrients in the water, inhibit excessive algae growth, improve water transparency, and enhance underwater lighting conditions, thereby achieving efficient purification of wastewater.

[0018] Preferably, in step S4, submerged plants are arranged in the shallow water area of ​​the ecological stability zone according to the ratio of Vallisneria natans: Potamogeton pectinatus: Potamogeton malaianus = 5:3:2, and aquatic plants are arranged in the deep water area according to the ratio of Vallisneria natans: Potamogeton pectinatus: Potamogeton malaianus = 2:4:4. The plant density is 80 plants / m² for Vallisneria natans and 50 plants / m² for other plants, and the submerged plant coverage is ≥80%.

[0019] By adopting the above technical solutions, the types and densities of submerged plants were rationally configured according to different water depths in the ecologically stable zone, ensuring the diversity and stability of the aquatic plant community. Specifically, in the shallow water area, Vallisneria natans, Potamogeton pectinatus, and Potamogeton malaianus were arranged in a 5:3:2 ratio, which helps to fully utilize the purification advantages of different plants and improve the absorption capacity of nutrients such as nitrogen and phosphorus in the water. In the deep water area, Vallisneria natans, Potamogeton pectinatus, and Potamogeton malaianus were arranged in a 2:4:4 ratio, which is adapted to the characteristics of the deep water environment and enhances the fixation and transformation of pollutants in the bottom sediment by the plant roots. At the same time, the plant density was specified as 80 plants / m² for Vallisneria natans and 50 plants / m² for other plants, and the coverage rate of submerged plants was guaranteed to be no less than 80%. This not only improved the purification efficiency of the tailwater but also effectively prevented the competitive inhibition caused by excessive plant density, thereby ensuring the long-term stable operation of the entire ecosystem and excellent landscape effect.

[0020] An ecological treatment structure for wastewater purification includes a composite ecological filter bed. The composite ecological filter bed comprises a gravel layer, a filter media layer, and an emergent plant layer arranged from bottom to top. An aeration water distribution pipe is embedded in the gravel layer. An inlet channel and an outlet channel are respectively provided on both sides of the composite ecological filter bed. One end of the aeration water distribution pipe is connected to the inlet channel so that the wastewater in the inlet channel can flow into the composite ecological filter bed. An aeration system is externally connected to the aeration water distribution pipe to introduce air into the aeration water distribution pipe. An overflow port is provided on one side of the composite ecological filter bed so that the water in the composite ecological filter bed can flow into the outlet channel.

[0021] By adopting the above technical solution, the effluent is sequentially treated through the gravel layer, filter media layer, and emergent plant layer of the composite ecological filter bed, effectively achieving the synergistic effect of physical filtration, chemical adsorption, and biodegradation, significantly reducing the nitrogen and phosphorus content in the water. The design of the aeration distribution pipes ensures a sufficient oxygen supply, promoting the activity of aerobic microorganisms and improving the decomposition efficiency of organic matter. Simultaneously, the rational water flow organization and gas distribution help form a stable biofilm environment, enhancing the nitrification and denitrification processes. Ultimately, this structure can stably output purified water that meets the Class III water quality standard of the "Surface Water Environmental Quality Standard," combining high efficiency and stability.

[0022] Preferably, the aeration water distribution pipe includes an inner pipe and an outer pipe. The end of the inner pipe forms an inlet section that communicates with the inlet channel. The diameter of the inlet section connected to the inlet channel is smaller than the diameter of the end connected to the inner pipe. The port of the aeration system connected to the inner pipe is located downstream of the inlet section. A bend is formed between the end of the inner pipe away from the inlet section and the outer pipe. The tailwater flows sequentially along the inner pipe and the bend into the channel between the outer pipe and the inner pipe. The outer pipe is provided with an outlet hole so that the tailwater can flow into the gravel layer.

[0023] By adopting the above technical solution, the special structural design of the aeration distribution pipe effectively improves the mixing efficiency of effluent and air. The bends formed by the inner and outer pipes and the placement of the outlet holes ensure that the effluent can fully contact the air before entering the gravel layer, thereby increasing the dissolved oxygen content in the water, which is beneficial to the subsequent growth and reproduction of microorganisms and the degradation of pollutants. At the same time, the unique diameter design of the inlet helps to control the effluent flow rate, preventing the gas from failing to fully dissolve in the water due to excessive flow velocity, thus improving the overall treatment efficiency of the ecological filter bed.

[0024] Preferably, the top of the inner wall of the inner tube is provided with a guide block, and the guide block has a guide surface on the side facing the tailwater flow direction. The guide surface can guide the bubbles and tailwater to move downwards. The side of the guide block facing away from the tailwater flow is concave to form a groove to restrict the rising bubbles from contacting the guide block.

[0025] By adopting the above technical solution, when the bubbles flow with the tailwater in the inner pipe, the bubbles are located at the top of the inner pipe. When the bubbles flow past the guide block, they flow towards the bottom of the inner pipe under the guidance of the guide surface. When the bubbles pass the guide block, they rise to the top of the inner pipe in the tailwater. During the rising process, the bubbles do not contact the guide block, which increases the contact area between the bubbles and the tailwater and improves the dissolution rate of the gas in the tailwater. This can reduce the aeration flow rate and reduce the energy consumption of the aeration system while keeping the dissolved oxygen concentration in the tailwater constant.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. The proposed scheme does not involve fish disturbance. It relies on submerged plants (coverage ≥80%) and microbial communities to form a stable ecological barrier. Microorganisms and plants work together to directly remove nitrogen, and animals only assist in removing impurities. There is no additional nitrogen load, thus ensuring the stability of the purification system.

[0028] 2. The porous structure of the filter media significantly increases the surface area for microbial attachment, forming a rich biofilm. The biofilm naturally stratifies, with aerobic and anoxic zones coexisting, thereby achieving simultaneous nitrification and denitrification processes, simplifying the process flow, reducing energy consumption and operating costs, and ensuring stable effluent quality that meets standards.

[0029] 3. When the bubbles flow with the tailwater in the inner pipe, the bubbles are located at the top of the inner pipe. When the bubbles flow past the guide block, they flow towards the bottom of the inner pipe under the guidance of the guide surface. When the bubbles pass the guide block, they rise to the top of the inner pipe in the tailwater. During the rising process, the bubbles do not contact the guide block, which increases the contact area between the bubbles and the tailwater and improves the dissolution rate of the gas in the tailwater. This can reduce the aeration flow rate and reduce the energy consumption of the aeration system while keeping the dissolved oxygen concentration in the tailwater constant. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a tailwater purification and ecological treatment structure according to an embodiment of this application.

[0031] Figure 2 yes Figure 1 Enlarged view of section A.

[0032] Figure 3 yes Figure 1 Enlarged view of section B in the middle.

[0033] Figure 4 This is a flowchart of an ecological treatment process for wastewater purification according to an embodiment of this application.

[0034] Explanation of reference numerals in the attached diagram: 1. Composite ecological filter bed; 11. Impermeable layer; 12. Gravel layer; 13. Filter media layer; 14. Emergent plant layer; 15. Aeration distribution pipe; 151. Inner pipe; 152. Outer pipe; 153. Water inlet; 154. Solenoid valve; 155. Sealing cap; 156. Bend; 157. Water outlet; 161. Guide block; 162. Guide surface; 163. Groove; 2. Water outlet channel; 21. Overflow port; 3. Water inlet channel; 4. Air pipe. Detailed Implementation

[0035] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0036] The inventors of this application have discovered that existing wastewater purification processes suffer from reduced denitrification efficiency due to increased ammonia nitrogen load caused by fish excrement. Furthermore, fish mortality or overpopulation can lead to water quality deterioration and even system collapse. Therefore, this application primarily employs a wastewater purification scheme that eliminates the need for fish introduction and achieves stable and efficient purification through multiple ecological treatment units. This approach offers significant advantages, including avoiding secondary pollution, improving purification efficiency, and maintaining long-term system stability.

[0037] This application discloses an ecological treatment structure for wastewater purification.

[0038] Reference Figure 1An ecological treatment structure for wastewater purification includes a composite ecological filter bed 1. This embodiment only shows two composite ecological filter beds 1. The composite ecological filter bed 1 can be transformed from a natural pond or artificially excavated. Each composite ecological filter bed 1 includes, from bottom to top, an impermeable layer 11, a gravel layer 12, a filter media layer 13, and an emergent plant layer 14. The impermeable layer 11 is made of clay material, and a low-permeability layer is formed by compacting the clay. The gravel layer 12 uses pebbles or multi-faceted crushed stone with a particle size of 30-50mm as the base material, forming certain gaps between them. An aeration water distribution pipe 15 is buried in the gravel layer 12.

[0039] Reference Figure 1 A water outlet channel 2 is provided between the two composite ecological filter beds 1. Each composite ecological filter bed 1 has an inlet channel 3 on the side opposite to the water outlet channel 2. Each inlet channel 3 is used in conjunction with a distribution channel. One end of the aeration distribution pipe 15 is connected to the inlet channel 3, allowing the effluent in the inlet channel 3 to enter the composite ecological filter bed 1 through the aeration distribution pipe 15. Then, through the gaps between the gravel layers 12, horizontal water distribution is achieved, resulting in a more uniform rise in the effluent level. The porous filter media layer 13 is composed of volcanic rock, ceramsite, or other natural mineral materials, with a weight controlled within the range of 400kg to 600kg per cubic meter for easy handling and maintenance. The complex network space formed inside the filter media allows for gradient changes in dissolved oxygen concentration, thus supporting the coexistence and symbiosis of aerobic and anaerobic bacteria. For example, volcanic rock has good air permeability and a large specific surface area, making it very suitable for microbial attachment and growth.

[0040] Reference Figure 1 The emergent plant layer 14 can be selected from reeds, variegated reeds, umbrella grass, pickerelweed, yellow iris, calamus, aquatic canna, sweet flag, cattail, and thaliana, depending on the regional climate and geological features. An air pipe 4 is pre-embedded within the filter layer 13. Both the air pipe 4 and the aeration cloth water pipe 15 are connected to an external aeration system. The aeration system mainly includes a blower and pipes. The blower is connected to the air pipe 4 and the aeration cloth water pipe 15 through pipes, allowing air to be introduced into both. The air pipe 4 provides oxygen to the emergent plants, preventing root rot.

[0041] Reference Figure 1 , Figure 2An overflow outlet 21 is provided on the embankment on the side of the composite ecological filter bed 1 near the outlet channel 2. The overflow outlet 21 is higher than the filter media layer 13 by a certain height. The aeration water distribution pipe 15 includes an inner pipe 151 and an outer pipe 152. The inner pipe 151 and the outer pipe 152 are coaxially arranged and fixedly connected to the embankments on both sides of the composite ecological filter bed 1. One end of the inner pipe 151 is inserted into the inlet channel 3, and the end of the inner pipe 151 inserted into the inlet channel 3 forms the inlet section 153, which is a conical end. The inlet of the inlet section 153 is designed such that its diameter at the connection point with the inlet channel 3 is smaller than its diameter at the connection point with the inner pipe 151. The aeration system pipe is fixed at the end of the inner pipe 151 that is inserted into the inlet channel 3, and the connection port with the inner pipe 151 is located downstream of the inlet section 153. Because the diameter of the inlet end of the inlet section 153 is smaller than the diameter of the other end, the water pressure at the inlet end of the inlet section 153 is greater than that at the other end, thus effectively preventing air bubbles in the effluent from entering the inlet channel 3. The unique diameter design of the inlet section 153 helps control the effluent flow rate, preventing the gas from failing to fully dissolve in the water due to excessive flow velocity, thereby improving the overall treatment efficiency of the ecological filter bed.

[0042] Reference Figure 1 , Figure 2 The inlet section 153 is equipped with an electromagnetic valve 154 at its front end, which is used to control the opening and closing of the inlet section 153. When the tailwater in the composite ecological filter bed 1 is filled to a specified height, the electromagnetic valve 154 is closed. When the tailwater in the composite ecological filter bed 1 is purified, the electromagnetic valve 154 is opened, and the tailwater in the inlet channel 3 enters the composite ecological filter bed 1, raising the liquid level of the purified tailwater, and then the purified tailwater flows from the overflow port 21 into the outlet channel 2, realizing the discharge of the purified tailwater.

[0043] Reference Figure 1 , Figure 3 The end of the inner pipe 151 furthest from the inlet 153 is connected to the outlet channel 2, and this end is equipped with a sealing cap 155, which is normally closed. When it is necessary to discharge all the tailwater in the composite ecological filter bed 1 at once, the sealing cap 155 is opened, allowing all the tailwater to be discharged into the outlet channel 2. The inner pipe 151 has a through hole at the end furthest from the inlet 153, forming a bend 156. At this time, the tailwater enters the inner pipe 151 from the inlet 153, flows along the inner pipe 151 to the bend 156, and then flows into the channel between the inner pipe 151 and the outer pipe 152. The outer pipe 152 has multiple outlet holes 157, which are spaced apart along the length of the outer pipe 152. The tailwater in the channel between the inner pipe 151 and the outer pipe 152 flows into the gravel layer 12 through the outlet holes 157, increasing the uniformity of tailwater distribution in the composite ecological filter bed 1.

[0044] The bend 156 formed by the inner pipe 151 and the outer pipe 152, as well as the outlet hole 157, ensure that the tailwater can fully contact the air before entering the gravel layer 12, thereby increasing the dissolved oxygen content in the water, which is conducive to the subsequent growth and reproduction of microorganisms and the degradation of pollutants.

[0045] Reference Figure 1 , Figure 2 The inner wall of the inner tube 151 has multiple guide blocks 161 at its top. These guide blocks 161 are spaced apart along the length of the inner tube 151. Each guide block 161 has a guide surface 162 on the side facing the tailwater flow direction. The guide surface 162 is inclined towards the bottom of the inner tube 151 along the water flow direction, guiding the tailwater and air bubbles towards the bottom of the inner tube 151. The side of the guide block 161 facing away from the tailwater flow forms a recess 163. The arrangement of the guide surface 162 and the recess 163 results in a dovetail-shaped cross-section for the guide block 161. A pointed tip is formed at the connection between the guide surface 162 and the groove wall 163. When the bubble passes the guide surface 162, the bubble rises along the water flow direction toward the top of the inner tube 151. During the rise of the bubble, the bubble does not contact the guide block 161. Each time it passes the guide block 161, the bubble descends and then rises again. During this process, the bubble comes into contact with the tailwater, increasing the contact area between the bubble and the tailwater and improving the dissolution rate of the gas in the tailwater. This can reduce the aeration flow rate and reduce the energy consumption of the aeration system while keeping the dissolved oxygen concentration in the tailwater constant.

[0046] The implementation principle of the tailwater purification ecological treatment structure in this application embodiment is as follows: When the tailwater is discharged into the composite ecological filter bed 1, the solenoid valve 154 is opened, and the tailwater in the inlet channel 3 enters the inner pipe 151, and enters the gravel layer 12 along the inner pipe 151 and the outer pipe 152, and rises along the gravel layer 12 and the filter media layer 13 to the emergent plant layer 14, which is located below the overflow outlet 21. On the other hand, the aeration system introduces air into the inner pipe 151, and the air forms bubbles in the inner pipe 151, which move along the water flow direction at the top of the inner pipe 151. When the bubbles pass the guide block At point 161, guide surface 162 guides the tailwater and air bubbles to flow towards the bottom of inner pipe 151. When the air bubbles pass over guide surface 162, they rise towards the top of inner pipe 151 along the water flow direction. During the rise of the air bubbles, they do not contact guide block 161. Each time they pass guide block 161, the air bubbles descend and then rise again. During this process, the air bubbles come into contact with the tailwater, increasing the contact area between the air bubbles and the tailwater, and improving the solubility of the gas in the tailwater. This allows for a reduction in aeration flow rate and lower energy consumption of the aeration system while maintaining a constant dissolved oxygen concentration in the tailwater.

[0047] After the effluent purification in the composite ecological filter bed 1 is completed, the solenoid valve 154 is opened, and the effluent in the inlet channel 3 enters the composite ecological filter bed 1, raising the liquid level of the purified effluent, and then the purified effluent flows from the overflow port 21 into the outlet channel 2, realizing the discharge of the purified effluent.

[0048] This application discloses an ecological treatment process for wastewater purification.

[0049] Reference Figure 4 An ecological treatment process for wastewater purification includes the following steps:

[0050] S1. Ecological Enhancement Zone Treatment: The effluent is introduced into the ecological enhancement zone, where it undergoes preliminary purification by passing through a composite ecological filter bed 1, an artificial aquatic plant purification belt, a three-dimensional ecological floating bed, and a pollution-tolerant plant purification belt. The purified TN is ≤4mg / L.

[0051] The composite ecological filter bed 1 includes a gravel bed, filter media, emergent plants, and aeration pipes. The gravel layer 12 uses pebbles or multi-faceted crushed stone with a particle size of 30-50mm as the base material, forming certain gaps between them. Aeration pipes are embedded in the gravel layer 12, and the aeration intensity of the aeration pipes is 18-22L / (m²·s). This aeration intensity promotes the metabolic activities of aerobic microorganisms, improves the efficiency of nitrification, and ultimately achieves the effect of efficient nitrogen and phosphorus removal.

[0052] The filter media is composed of porous volcanic rock, ceramsite, or other natural mineral materials, with a weight controlled within the range of 400kg to 600kg per cubic meter for easy handling and maintenance. The porous structure of the filter media significantly increases the surface area for microbial attachment, forming a rich biofilm. The biofilm naturally stratifies, with aerobic and anoxic zones coexisting, thus achieving simultaneous nitrification and denitrification processes. This design effectively improves nitrogen removal efficiency while simplifying the process flow, reducing energy consumption and operating costs, and ensuring stable and compliant effluent quality.

[0053] Emergent plants can be selected according to the regional climate and geological features, such as reeds, variegated reeds, umbrella grass, pickerelweed, yellow iris, sweet flag, aquatic canna, sweet flag, cattail, and thalia.

[0054] Artificial aquatic plant purification zones utilize biocompatible materials as carriers, such as modified bamboo fiber and natural plant fibers (e.g., coconut shell fiber), to promote microbial attachment. The artificial aquatic plants employ a three-dimensional mesh design, such as brush-like or honeycomb-like structures, to enhance microbial attachment and oxygen exchange efficiency. The artificial aquatic plants are secured to the pond bottom using weights (concrete blocks, stones) or steel stakes, with spacing adjusted to 20-50 cm based on water flow velocity and water pollution load. Initial addition of activated sludge or highly efficient bacterial strains (e.g., nitrifying and denitrifying bacteria) accelerates biofilm formation and replenishes carbon sources (e.g., glucose) or trace elements, optimizing the microbial metabolic environment. A flow guide or pump controls the water flow slowly through the artificial aquatic plant zone, extending the hydraulic retention time.

[0055] The artificial aquatic plants have a specific surface area of ​​≥250m² / m², which effectively adsorbs pollutants in the water and improves purification efficiency. Their tensile strength is ≥10KN / m, ensuring stability under water flow impact and extending service life. The laying density is 8-12 plants / m², a reasonable density that guarantees sufficient purification capacity while avoiding maintenance difficulties caused by excessive density, thus achieving effective removal of pollutants such as nitrogen and phosphorus from the effluent.

[0056] The floating bed frame of the three-dimensional ecological floating bed uses lightweight, corrosion-resistant, and environmentally friendly materials such as PVC pipes, bamboo, recycled plastics, or foam boards. A mesh structure (nylon or metal mesh) is added to the bottom of the frame to support the substrate and plants while maintaining smooth water flow. Porous, lightweight materials such as expanded clay, biochar, coconut fiber, or synthetic fibers are used as the substrate filling material. The substrate is placed in permeable mesh bags and evenly laid within the frame mesh, or secured to the bottom of the frame with ropes to prevent loss. The upper layer of the three-dimensional ecological floating bed is planted with irises and sedges at a density of 9 clumps / m². Irises and sedges have strong root absorption and metabolic capabilities, effectively removing nitrogen and phosphorus nutrients from the water while beautifying the aquatic landscape. The lower layer contains suspended artificial aquatic plants, 1.2-1.8m in length, with an area 1.2-1.8 times the area of ​​the floating bed. These artificial aquatic plants provide a large specific surface area, which is conducive to the formation and growth of microbial films, thereby further enhancing the adsorption and degradation of organic matter and suspended particles.

[0057] The pollution-tolerant plant purification zone consists of submerged plants such as Hydrilla verticillata, Myriophyllum spicatum, Ceratophyllum demersum, and Potamogeton crispus, arranged at a density of 72 plants per square meter. It can effectively absorb nitrogen and phosphorus nutrients in the water, inhibit excessive algae growth, improve water transparency, and enhance underwater lighting conditions, thereby achieving highly efficient purification of wastewater.

[0058] S2. Ecological buffer zone treatment: The effluent from the ecological enhancement zone is introduced into the ecological buffer zone, where submerged plants in the ecological buffer zone perform secondary purification of the effluent. The purified TN is ≤3mg / L.

[0059] The ecological buffer zone is planted with submerged plants in a ratio of Vallisneria natans: Potamogeton pectinatus: Ceratophyllum demersum: Potamogeton malaianus: Potamogeton pectinatus = 6:1:1:1:1. In the riparian zone, especially in areas with good hydrophilicity, submerged plants, primarily Vallisneria natans, are planted. This rationally proportioned submerged plant system in the ecological buffer zone provides secondary purification of the wastewater, effectively removing residual organic matter and nitrogen and phosphorus nutrients.

[0060] S3. Ecological Demonstration Zone Treatment: While maximizing the purification effect, the ecological demonstration zone enhances the landscape effect of the water body. In the shallow water area of ​​the ecological demonstration zone, Vallisneria natans: Potamogeton pectinatus: Potamogeton pectinatus = 8:1:1 is planted, and in the deep water area, Vallisneria natans: Potamogeton pectinatus: Potamogeton pectinatus is planted in a ratio of 1:6:3. The effluent after treatment in the ecological buffer zone is introduced into the ecological demonstration zone and purified three times. The TN in the purified effluent is ≤2mg / L.

[0061] S4. Treatment in the ecological stabilization zone: Submerged plants, floating-leaved plants, and emergent plants are planted in the ecological stabilization zone to construct an aquatic plant community. Zooplankton, benthic animals, and microorganisms are then introduced to optimize the community. The treated effluent from the ecological demonstration zone is then introduced into the ecological stabilization zone for four purification processes. The TN in the purified effluent is ≤1.5mg / L, and the effluent quality consistently meets the Class III water quality standard (TN≤1.5mg / L) of the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0062] In the shallow water area of ​​the ecological stability zone, submerged plants are arranged in a ratio of Vallisneria natans: Potamogeton microdentula: Potamogeton malaianus = 5:3:2, while in the deep water area, aquatic plants are arranged in a ratio of Vallisneria natans: Potamogeton microdentula: Potamogeton malaianus = 2:4:4. This helps to fully utilize the purification advantages of different plants and improve the absorption capacity of nutrients such as nitrogen and phosphorus in the water. The plant density is 80 plants / m² for Vallisneria natans and 50 plants / m² for other plants, with a submerged plant coverage rate of ≥80%. This not only improves the purification efficiency of the tailwater but also effectively prevents the competitive inhibition caused by excessive plant density, thereby ensuring the long-term stable operation of the entire ecosystem and excellent landscape effect.

[0063] For floating-leaved plants, choose water lilies. For emergent plants, depending on the regional climate and geological features, you can choose reeds, variegated reeds, umbrella grass, pickerelweed, yellow iris, sweet flag, aquatic canna, sweet flag, cattail, thalia, etc.

[0064] Zooplankton are cladocerans, such as water fleas and daphnia, which feed on algae and suspended particles. Benthic animals are mollusks and crustaceans, such as freshwater mussels, snails, and freshwater mussels, which filter-feed on suspended matter and algae; amphipods, which decompose organic matter in the bottom mud; and mysids and prawns, which feed on organic debris and algae.

[0065] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An ecological treatment process for effluent purification, characterized in that: Includes the following steps: S1. Ecological Enhancement Zone Treatment: The effluent is introduced into the ecological enhancement zone and undergoes preliminary purification by passing through the composite ecological filter bed (1), artificial aquatic plant purification belt, three-dimensional ecological floating bed and pollution-resistant plant purification belt in sequence. S2. Ecological buffer zone treatment: The effluent from the ecological enhancement zone is introduced into the ecological buffer zone, where the effluent is purified a second time by submerged plants in the ecological buffer zone. Submerged plants are planted in the following ratio: Vallisneria natans: Potamogeton pectinatus: Ceratophyllum demersum: Potamogeton malaianus: Potamogeton pectinatus = 6:1:1:1:

1. S3. Ecological demonstration area treatment: In the shallow water area of ​​the ecological demonstration area, Vallisneria natans: Potamogeton pectinatus: Potamogeton pectinatus = 8:1:1, and in the deep water area, Vallisneria natans: Potamogeton pectinatus: Potamogeton pectinatus = 1:6:

3. The effluent after treatment in the ecological buffer zone is introduced into the ecological demonstration area for three purification processes. S4. Ecological stabilization zone treatment: Submerged plants, floating-leaved plants, and emergent plants are arranged in the ecological stabilization zone to construct an aquatic plant community. Zooplankton, benthic animals, and microorganisms are then introduced to optimize the community. The treated effluent from the ecological demonstration zone is then introduced into the ecological stabilization zone for four purification processes. The composite ecological filter bed (1) includes a gravel bed, filter media, emergent plants, and aeration pipes. It removes nitrogen and phosphorus through physical filtration, chemical adsorption, and the synergistic effect of biofilm. The wastewater retention time is 1.3-1.7 hours; The filter media porosity is 70%-75%; The filtration rate is 0.5-0.7 m / h; The aeration intensity is 18-22 L / (m²·s); The three-dimensional ecological floating bed includes an upper layer planted with irises and coin grass at a density of 9 clumps / m², and a lower layer with suspended artificial aquatic plants, 1.2-1.8m in length, accounting for 1.2-1.8 times the area of ​​the floating bed. In step S4, submerged plants are arranged in the shallow water area of ​​the ecological stability zone according to the ratio of Vallisneria natans: Potamogeton microdentula: Potamogeton malaianus = 5:3:2, and aquatic plants are arranged in the deep water area according to the ratio of Vallisneria natans: Potamogeton microdentula: Potamogeton malaianus = 2:4:

4. The plant density is 80 Vallisneria natans per square meter and 50 other plants per square meter. The coverage rate of submerged plants is ≥80%.

2. The effluent purification and ecological treatment process according to claim 1, characterized in that: The filter media has a porous structure, which allows microorganisms to attach to the filter media and form aerobic and anoxic zones. The microorganisms undergo nitrification in the aerobic zone and denitrification in the anaerobic zone.

3. The effluent purification and ecological treatment process according to claim 1, characterized in that: In the artificial aquatic plant purification belt, the artificial aquatic plants have a specific surface area ≥250m² / m², a tensile strength ≥10KN / m, and a laying density of 8-12 plants / m².

4. The effluent purification and ecological treatment process according to claim 1, characterized in that: The pollution-resistant plant purification zone includes *Hydrilla verticillata*, *Myriophyllum spicatum*, *Ceratophyllum demersum*, and *Potamogeton crispus*, arranged at 72 plants per square meter.

5. A tailwater purification and ecological treatment structure, using the tailwater purification and ecological treatment process described in any one of claims 1-4, characterized in that: The composite ecological filter bed (1) includes a gravel layer (12), a filter media layer (13), and an emergent plant layer (14) arranged from bottom to top. An aeration water distribution pipe (15) is buried in the gravel layer (12). An inlet channel (3) and an outlet channel (2) are respectively provided on both sides of the composite ecological filter bed (1). One end of the aeration water distribution pipe (15) is connected to the inlet channel (3) so that the tailwater in the inlet channel (3) can flow into the composite ecological filter bed (1). An aeration system is connected to the aeration water distribution pipe (15) so that air can be introduced into the aeration water distribution pipe (15). An overflow port (21) is provided on one side of the composite ecological filter bed (1) so that the water in the composite ecological filter bed (1) can flow into the outlet channel (2). The aeration water distribution pipe (15) includes an inner pipe (151) and an outer pipe (152). The end of the inner pipe (151) forms an inlet section (153) that communicates with the inlet channel (3). The diameter of the inlet section (153) connected to the inlet channel (3) is smaller than the diameter of the inlet section (151). The port of the aeration system that communicates with the inner pipe (151) is located downstream of the inlet section (153). The inner pipe (151) forms a bend (156) with the outer pipe (152) at the end away from the water inlet (153). The tailwater flows into the channel between the outer pipe (152) and the inner pipe (151) in sequence along the inner pipe (151) and the bend (156). The outer pipe (152) is provided with a water outlet (157) so that the tailwater can flow into the gravel layer (12). The inner wall of the inner tube (151) is provided with a guide block (161) at the top. The guide block (161) has a guide surface (162) on the side facing the tailwater flow direction. The guide surface (162) can guide the bubbles and tailwater to move downward. The side of the guide block (161) facing away from the tailwater flow is concave to form a groove (163) to restrict the rising bubbles from contacting the guide block (161).

Images