Rotating tower multi-stage tidal flow artificial wetland system and sewage treatment method

Abstract

The present invention discloses a rotating tower multi-stage tidal flow artificial wetland system and a sewage treatment method, comprising a central purification wetland, wherein multiple layers of annular wetlands are installed around the outside of the central purification wetland in descending order, wherein each layer of annular wetlands is composed of multiple fan-shaped purification units, and a water inlet is provided at the upper end of the central purification wetland. A first rotating drainer is installed at the top of the first water collection channel, and a second rotating drainer is installed at the top of the second water collection channel. The first rotating drainer is used to drain water in a rotating waterfall to the top of the adjacent annular wetland, and the second rotating drainer is used to drain water in a rotating waterfall to the top of the outer annular wetland. The present invention forms a tidal flow effect by surrounding the central purification wetland with multiple layers of coaxial annular wetlands outside the central purification wetland, and drains water in the form of a rotating waterfall through the first and second rotating drainers, thereby achieving efficient denitrification of sewage.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a rotating tower multi-stage tidal flow artificial wetland system and a sewage treatment method. Background Art

[0002] Nitrogen pollution is the main cause of eutrophication of water bodies, and the removal of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in sewage treatment has become an important issue in environmental protection. Traditional sewage treatment processes mostly rely on the alternation of aerobic and anaerobic processes in physical, chemical and biological processes to achieve denitrification, especially nitrification and denitrification. However, traditional processes have problems such as high operating costs, complex structures, large space occupation, and uneven distribution of dissolved oxygen, which limit the denitrification efficiency. Artificial wetlands have become an emerging technology in the field of sewage treatment due to their advantages such as low energy consumption, environmental protection, and simple operation and maintenance. Tidal flow artificial wetlands provide alternating aerobic and anoxic environments by simulating natural tidal phenomena, thereby enhancing the efficiency of nitrification-denitrification, but there is still room for improvement in the deep denitrification of sewage. Therefore, the present invention proposes a rotating tower multi-stage tidal flow artificial wetland system and a sewage treatment method. Summary of the Invention

[0003] In order to solve the current technical problems, the main purpose of the present invention is to provide a rotating tower multi-stage tidal flow artificial wetland system and a sewage treatment method, which can achieve efficient denitrification of sewage through coaxial nested design and tidal flow effect.

[0004] In order to overcome the problems existing in the prior art, the technical solution adopted by the present invention is: a rotating tower multi-stage tidal flow artificial wetland system, including a central purification wetland, the outside of the central purification wetland is surrounded by multiple layers of annular wetlands in sequence from high to low, and the annular wetlands of each layer are respectively composed of multiple fan-shaped purification units, a first water collection channel is provided between the central purification wetland and the adjacent annular wetlands, the bottom of the first water collection channel is connected with the bottom of the central purification wetland, each of the fan-shaped purification units corresponding to the inner side between adjacent annular wetlands is respectively provided with a second water collection channel, the bottom of the second water collection channel is connected with the bottom of the corresponding fan-shaped purification unit on the inner side, a drainage channel is provided on the outer side of the outermost annular wetland, and a drainage outlet is provided on the outer side of the upper end of the drainage channel;

[0005] A water inlet is provided at the upper end of the central purification wetland, a first rotary drainer is installed at the top of the first water collection channel, and a second rotary drainer is installed at the top of the second water collection channel. The first rotary drainer is used to rotate and cascade drainage to the top of the adjacent annular wetland, and the second rotary drainer is used to rotate and cascade drainage to the top of the outer annular wetland.

[0006] The central purification wetland includes a central container, a water inlet is arranged on the top of the central container, a first water collection channel is arranged on the outer wall of the central container, and the central container is filled with a first nitrification treatment matrix.

[0007] The first nitrification treatment matrix is ​​provided with three layers, which are a porous light matrix, an aggregate matrix and a denitrification matrix from top to bottom.

[0008] The first rotary drainer includes a rotating groove ring, a first gear ring and a first motor. A support ring is fixedly installed at the upper inner hole of the rotating groove ring. A limit ring is fixedly installed on the top of the central purification wetland. The support ring is movably mounted on the outside of the limit ring. The inner hole of the support ring is installed with a first gear ring. The first motor is installed on the top of the central purification wetland. The output shaft of the first motor is installed with a first gear, and the first gear ring is engaged with the first gear for transmission. A first water outlet is provided on the outside of the first water collecting channel, and the first water outlet extends into the rotating groove ring. At least one first water outlet pipe is installed on the lower side of the rotating groove ring.

[0009] The fan-shaped purification unit located in the inner layer includes a first fan-shaped container, the top of the first fan-shaped container is open, the outer wall of the first fan-shaped container is provided with a second water collection channel, and the first fan-shaped container is filled with a second nitrification treatment matrix.

[0010] The second nitrification treatment matrix is ​​provided with two layers, which are a porous matrix and a denitrification enhancement matrix from top to bottom.

[0011] The second rotary drainer includes a first rotating ring, a second gear ring and a second motor. A second water outlet is provided on the second water collecting channel. A supporting ring is fixedly installed on the outer wall of the annular wetland below the second water outlet. A movable set on the supporting ring supports a rotating ring. The first rotating ring is installed on the rotating ring. A second gear ring is also installed on the rotating ring. The second motor is installed on the outer wall of the annular wetland. A second gear is installed on the output shaft of the second motor. The second gear ring is engaged with the second gear for transmission. At least one second water outlet pipe is installed on the lower side of the first rotating ring.

[0012] The second rotating drainer also includes a second rotating ring, which is located above the first rotating ring. The bottom of the second rotating ring is connected to a drain pipe, which passes through the first rotating ring and is fixedly connected to the first rotating ring. A third water outlet is also provided on the second water collection channel above the second water outlet. The third water outlet is used to divert water into the second rotating ring. The second water outlet and the third water outlet are respectively installed with a first control valve and a second control valve.

[0013] The fan-shaped purification unit located at the outermost layer includes a second fan-shaped container, the top of the second fan-shaped container is open, the drainage channel is arranged on the outer wall of the second fan-shaped container, and the second fan-shaped container is filled with a functional matrix that supplies organic electrons or inorganic electrons.

[0014] A sewage treatment method adopts the rotating tower multi-stage tidal flow artificial wetland system, and the treatment method comprises the following steps:

[0015] S1. Sewage enters from the water inlet of the central purification wetland;

[0016] S2, sewage undergoes nitrification reaction in an aerobic environment from top to bottom and enters the first water collection channel from the bottom;

[0017] S3. The water in the first water collection channel flows from bottom to top into the first rotary drainer and is then discharged to the outer adjacent annular wetland surface in the form of a rotary waterfall;

[0018] S4: In this layer of circular wetland, water flows from top to bottom through nitrification in an anoxic environment and then enters the second water collection channel from the bottom.

[0019] S5. The water in the second water collection channel flows from bottom to top into the second rotary drainer and is discharged to the outer adjacent annular wetland surface in the form of a rotary waterfall;

[0020] S6. Finally, the water is discharged to the outermost annular wetland surface in the form of a rotating waterfall. After nitrification treatment in an anaerobic environment from top to bottom, the water enters the drainage channel from the bottom and is finally discharged from the drain outlet.

[0021] The present invention has the following beneficial effects:

[0022] 1. This invention utilizes multiple layers of coaxial annular wetlands surrounding a central purification wetland. Discharge is achieved through first and second rotary drainers in the form of a rotating waterfall, creating a tidal flow effect and achieving efficient denitrification of wastewater. Nitrification and denitrification cycles are cyclically carried out within the multiple layers, ultimately achieving deep denitrification.

[0023] 2. The present invention controls the water level of the inner annular wetland by controlling the opening and closing of the first control valve and the second control valve, thereby achieving the purpose of breathing of the inner annular wetland, forming intermittent drainage, and strengthening the tidal flow effect.

[0024] 3. The present invention realizes a tidal flow effect through a rotating overflow weir, and the sewage in each layer of the wetland can undergo multiple nitrification and denitrification processes, effectively removing ammonia nitrogen and total nitrogen.

[0025] 4. The cylinder nesting design of the present invention improves space utilization and is suitable for sewage treatment scenarios in cities and places with limited space.

[0026] 5. In the present invention, when sewage falls from the upper layer to the lower layer through the first rotary drainer and the second rotary drainer, dissolved oxygen is restored, providing oxygen support for the next stage of nitrification process.

[0027] 6. The first rotary drainer and the second rotary drainer in the present invention can be adjusted by an automated control system to ensure uniform distribution of water flow and periodic tidal flow, thereby enhancing the stability and efficiency of sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a schematic cross-sectional structural diagram of the present invention.

[0030] Figure 2 It is a schematic diagram of the top structure of the present invention.

[0031] Figure 3 It is a schematic cross-sectional structural diagram of the first rotary drainer of the present invention.

[0032] Figure 4 It is a schematic cross-sectional structural diagram of the second rotary drainer of the present invention.

[0033] Figure 5 This is a schematic diagram of the three-dimensional structure of the second rotary drainer of the invention.

[0034] Reference numerals:

[0035] Central purification wetland 100, light matrix 101, aggregate matrix 102, denitrification matrix 103;

[0036] Central container 110, water inlet 111, limiting ring 112;

[0037] A first water collecting channel 120 and a first water outlet 121;

[0038] First rotary drainer 130, rotary groove ring 131, first water outlet 132, support ring 133, first gear ring 134, first motor 135, first gear 136;

[0039] The second annular wetland 200, porous matrix 201, denitrification enhancement matrix 202, first sector container 210, second water collection channel 220, second water outlet 221, third water outlet 222, first control valve 223, second control valve 224, and carrying ring 225;

[0040] Second rotary drainer 230 , first rotary ring 231 , second rotary ring 232 , drain pipe 233 , second water outlet 234 , rotating ring 235 , second ring gear 236 , second motor 237 , second gear 238 , partition 239 ;

[0041] The third layer of annular wetland 300 , functional matrix 301 , second fan-shaped container 310 , drainage channel 320 , and drainage outlet 321 .

[0042] Wetland plants 400. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0044] Example 1:

[0045] See also Figure 1-2 The present invention provides a rotating tower multi-stage tidal flow artificial wetland system, comprising a central purification wetland 100, wherein multiple layers of annular wetlands are installed around the outside of the central purification wetland 100 in sequence from high to low, wherein the annular wetlands of each layer are respectively composed of multiple fan-shaped purification units, a first water collection channel 120 is provided between the central purification wetland 100 and adjacent annular wetlands, the bottom of the first water collection channel 120 is connected to the bottom of the central purification wetland 100, a second water collection channel 220 is provided on each of the fan-shaped purification units corresponding to the inner side between adjacent annular wetlands, the bottom of the second water collection channel 220 is connected to the bottom of the corresponding fan-shaped purification unit on the inner side, a drainage channel 320 is provided on the outer side of the outermost annular wetland, and a drainage outlet 321 is provided on the outer side of the upper end of the drainage channel 320;

[0046] A water inlet 111 is provided at the upper end of the central purification wetland 100, a first rotary drainer 130 is installed at the top of the first water collection channel 120, and a second rotary drainer 230 is installed at the top of the second water collection channel 220. The first rotary drainer 130 is used to rotate and cascade drainage to the top of the adjacent annular wetland, and the second rotary drainer 230 is used to rotate and cascade drainage to the top of the outer annular wetland.

[0047] The central purification wetland 100 is surrounded by multiple layers of coaxial annular wetlands. The first and second rotary drainers 130 and 230 drain water in a rotating waterfall pattern, creating a tidal flow effect and achieving efficient denitrification of the wastewater. Nitrification and denitrification cycles within the multiple layers of wetlands ultimately achieve deep denitrification.

[0048] See also Figure 1 、 2 The central purification wetland 100 includes a central container 110 , a water inlet 111 is arranged at the top of the central container 110 , a first water collection channel 120 is arranged on the outer wall of the central container 110 , and the central container 110 is filled with a first nitrification treatment matrix.

[0049] Specifically, the first nitrification treatment matrix is ​​provided with three layers, which are, from top to bottom, a porous lightweight matrix 101 , an aggregate matrix 102 , and a denitrification matrix 103 .

[0050] In this embodiment, the lightweight substrate 101 is made of expanded perlite or lightweight ceramsite to promote nitrification reaction in an aerobic environment, ensuring sufficient dissolved oxygen in the water body, which is suitable for the growth and activity of nitrifying bacteria.

[0051] The aggregate-type matrix 102 is composed of crushed stone or volcanic rock. This type of matrix provides moderate water flow resistance and supports alternating aerobic and anoxic microenvironments.

[0052] The denitrifying substrate 103 is selected from organic matter containing organic carbon or capable of enhancing denitrification, such as sawdust, straw, wood chips, etc., to promote denitrification reaction and convert nitrate into nitrogen gas.

[0053] In this embodiment, see Figure 3 The first rotary drainer 130 includes a rotary groove ring 131, a first gear ring 134, and a first motor 135. A support ring 133 is fixedly installed at the upper inner hole of the rotary groove ring 131. A limit ring 112 is fixedly installed on the top of the central purification wetland 100. The support ring 133 is movably mounted on the outer side of the limit ring 112. A first gear ring 134 is installed in the inner hole of the support ring 133. The first motor 135 is installed on the top of the central purification wetland 100. The output shaft of the first motor 135 is installed with a first gear 136. The first gear ring 134 meshes with the first gear 136 for transmission. A first water outlet 121 is provided on the outer side of the first water collection channel 120. The first water outlet 121 extends into the rotary groove ring 131. At least one first water outlet pipe 132 is installed on the lower side of the rotary groove ring 131. Through the above structure, the rotary drainage of the first rotary drainer 130 is achieved.

[0054] When the first motor 135 rotates, it drives the first gear 136 to rotate, which in turn drives the first ring gear 134 to rotate. Since the first ring gear 134 is fixedly connected to the rotating groove ring 131, the rotating groove ring 131 rotates accordingly. When water in the first water collection channel 120 enters the rotating groove ring 131, it is discharged through the first water outlet 132.

[0055] See also Figure 1 、 2 The fan-shaped purification unit located in the inner layer includes a first fan-shaped container 210, the top of the first fan-shaped container 210 is open, the outer wall of the first fan-shaped container 210 is provided with a second water collection channel 220, and the first fan-shaped container 210 is filled with a second nitrification treatment matrix.

[0056] In this embodiment, the second nitrification treatment matrix is ​​provided with two layers, which are a porous matrix 201 and a denitrification enhancement matrix 202 from top to bottom.

[0057] Specifically, the porous matrix 201 is made of ceramsite or coarse sand to enhance nitrification reaction and provide a stable matrix for plant colonization. The porous structure is conducive to root growth and air entry.

[0058] The denitrification enhancement substrate 202 is made of wood chips, straw or rice husks. These materials can provide electron donors in an anaerobic environment and promote the denitrification process.

[0059] In this embodiment, see Figure 4 The second rotary drainer 230 includes a first rotating ring 231, a second ring gear 236, and a second motor 237. A second water outlet 221 is provided on the second water collection channel 220. A support ring 225 is fixedly mounted on the outer wall of the annular wetland below the second water outlet 221. A rotating ring 235 is movably supported on the support ring 225. The first rotating ring 231 is mounted on the rotating ring 235, which is also mounted on the second ring gear 236. A second motor 237 is mounted on the outer wall of the annular wetland. A second gear 238 is mounted on the output shaft of the second motor 237, and the second ring gear 236 meshes with the second gear 238 for transmission. At least one second water outlet pipe 234 is mounted on the lower side of the first rotating ring 231. With this structure, when the second motor 237 drives the second gear 238 to rotate, it drives the first rotating ring 231 to rotate, thereby achieving rotary drainage.

[0060] The supporting ring 225 plays the role of supporting the first rotating ring 231, and the rotating ring 235 plays the role of positioning. Figure 4 In the embodiment, the rotating ring 235 is L-shaped, so that the rotating ring 235 can rotate around the carrying ring 225.

[0061] Further, see Figure 4 The second rotary drainer 230 also includes a second rotating ring 232, located above the first rotating ring 231. A drain pipe 233 is connected to the bottom of the second rotating ring 232, passing through and securely connected to the first rotating ring 231. The second water collection channel 220 also includes a third water outlet 222, located above the second water outlet 221. The third water outlet 222 is used to divert water into the second rotating ring 232. The second and third water outlets 221 and 222 are respectively equipped with a first control valve 223 and a second control valve 224. By controlling the opening and closing of the first and second control valves 223 and 224, the water level of the inner annular wetland is controlled, allowing the inner annular wetland to breathe and creating intermittent drainage, enhancing the tidal flow effect.

[0062] In this embodiment, the first control valve 223 and the second control valve 224 are solenoid valves. When the first control valve 223 is opened, water is discharged from the second water outlet 221, lowering the water level in the inner annular wetland. When the first control valve 223 is closed and the second control valve 224 is opened, the water level in the inner annular wetland rises. During this period of rising water level, drainage to the next layer is suspended.

[0063] Furthermore, a plurality of partitions 239 are respectively installed in the first rotating ring 231 and the second rotating ring 232 to facilitate intermittent drainage in different zones.

[0064] See also Figure 1 、 2 The fan-shaped purification unit located at the outermost layer includes a second fan-shaped container 310, the top of the second fan-shaped container 310 is open, the drainage channel 320 is arranged on the outer wall of the second fan-shaped container 310, and the second fan-shaped container 310 is filled with a functional matrix 301 that supplies organic electronics or inorganic electronics.

[0065] In this embodiment, the functional matrix 301 is made of biochar, pyrite, and an artificial matrix material with enhanced electron donors to ensure continuous denitrification. The functional matrix 301 must have long-term water immersion stability and high denitrification efficiency.

[0066] Example 2:

[0067] Based on Example 1, see Figure 1 、 2 In the rotating tower multi-stage tidal flow artificial wetland system, the rotating tower multi-stage tidal flow artificial wetland system includes a central purification wetland 100 and an annular wetland, and the annular wetland includes a second-layer annular wetland 200 and a third-layer annular wetland 300.

[0068] The central purification wetland 100, the second annular wetland 200 and the third annular wetland 300 are arranged in a stepped structure from high to low. The second annular wetland 200 is the middle annular wetland, and the third annular wetland 300 is the outermost annular wetland.

[0069] The central purification wetland 100 is designed as a downward vertical subsurface artificial wetland. It functions as a nitrification-denitrification agent and also as a filter for suspended solids. Water enters from the surface layer and is discharged from the bottom layer. Vertically, dissolved oxygen gradually changes from an aerobic state to an anoxic state, first undergoing a nitrification process and then gradually changing to a denitrification process. Since the central purification wetland 100 is the deepest, the matrix needs to be layered and stepped vertically. The surface layer is mainly composed of a porous lightweight matrix, the middle layer is mainly composed of an aggregate matrix, and the bottom layer is mainly composed of a denitrification matrix. The sewage in the central purification wetland 100 is discharged from the bottom to the first water collection channel 120, and then the sewage is discharged from the top of the first water collection channel 120, and falls through the first rotary drainer 130 to the second-layer annular wetland 200. The dissolved oxygen is restored during the fall.

[0070] The second annular wetland 200 functions as a nitrification-denitrification system. Tidal drainage from the second annular wetland 200 is controlled primarily through two mechanisms: first, by controlling the opening and closing of the first control valve 223 and the second control valve 224, the water level in the upper porous matrix 201 is controlled, achieving the tidal flow effect of the constructed wetland. Second, by periodically rotating and draining water through the first rotary drainer 130, the four sector-shaped purification units within the second annular wetland 200 are switched between submerged states, achieving tidal flow.

[0071] The upper layer of the second circular wetland (200 meters) is designed as a breathing zone, alternating between aerobic, anoxic, and anaerobic states. Its primary function is nitrification, while also ensuring the colonization of wetland plants. Therefore, porous substrates are primarily selected for the wetland. The lower layer of the second artificial wetland is designed as a long-term soaking zone, primarily responsible for denitrification. Therefore, substrates that enhance denitrification performance are primarily selected.

[0072] The third annular wetland 300 is designed as a deep-bed denitrification wetland, primarily focusing on denitrification to achieve deep nitrogen removal. Therefore, the third annular wetland 300 remains submerged for extended periods to ensure the anaerobic performance of the wetland system. The low-dissolved oxygen effluent from the second annular wetland 200 flows slowly into the third annular wetland 300. Due to the limited organic carbon content in the influent after treatment in the two previous constructed wetlands, the system's heterotrophic denitrification capacity is limited. To ensure the denitrification and nitrogen removal effectiveness of the third annular wetland 300, the substrate must be a functional material capable of supplying organic or inorganic electrons.

[0073] The material selection for the rotating tower multi-stage tidal flow artificial wetland system of the present invention must meet the requirements of treatment effect, structural stability and long-term use. The matrix and construction materials should be scientifically selected according to the different functions of each layer of the wetland:

[0074] Central Purification Wetland 100: The surface substrate should be a lightweight material with high porosity, such as expanded perlite or lightweight ceramsite, to promote nitrification in an aerobic environment and ensure sufficient dissolved oxygen in the water for the growth and activity of nitrifying bacteria. The middle substrate should be a highly permeable aggregate-based substrate, such as crushed stone or volcanic rock. This type of substrate provides moderate flow resistance and supports alternating aerobic and anoxic microenvironments. The bottom substrate should contain organic carbon or materials that enhance denitrification, such as sawdust, straw, or wood chips, to promote denitrification and convert nitrates into nitrogen gas.

[0075] The second circular wetland layer (200 meters) is the intermediate circular wetland. The upper breathing layer uses a porous substrate, such as ceramsite or coarse sand, to enhance nitrification and provide a stable substrate for plant colonization. The porous structure facilitates root growth and air inflow. The lower soaking layer uses a substrate that enhances denitrification, such as wood chips, straw, or rice husks. These materials provide electron donors in anaerobic environments, promoting denitrification.

[0076] The third circular wetland, 300, or the outermost circular wetland, should be constructed with a functional matrix capable of supplying organic or inorganic electrons, such as biochar, pyrite, or artificial matrix materials with enhanced electron donors, to ensure continuous denitrification. The matrix must be stable under long-term waterlogging and possess high denitrification efficiency.

[0077] Example 3:

[0078] Based on Examples 1 or 2, the wetland plants 400 in the central purification wetland 100, the second annular wetland 200 (the middle annular wetland), and the third annular wetland 300 (the outermost annular wetland) play important ecological and treatment functions in the constructed wetland system. They not only provide a substrate for microorganisms to attach, but also absorb pollutants from the water and promote nitrification and denitrification through the oxidation-reduction action of their roots. In the rotating tower multi-stage tidal flow constructed wetland device of the present invention, different wetland layers require different plant selection requirements to adapt to their specific physical and chemical environments.

[0079] Plant Selection for the Central Purification Wetland 100: Functionally, the plants in the Central Purification Wetland 100 primarily help maintain an aerobic surface environment and provide a stable surface for root attachment, promoting the growth of nitrifying bacteria. Furthermore, the plants absorb some nitrogen, reducing ammonia nitrogen loads. Emergent plants with well-developed root systems, such as cattails and reeds, were selected. These plants thrive in both oxygen-rich and oxygen-deficient environments, making them well-suited to the conditions of vertical subsurface flow wetlands.

[0080] Plant Selection for the Second-Tier Circular Wetland (200): Functionally, the second-tier circular wetland (200) is designed as a tidal flow wetland, requiring plants to adapt to periodic flooding and drainage. Aerobic plants promote nitrification, provide a stable substrate during tidal flow, and effectively absorb nutrients such as nitrogen and phosphorus. Tidal-adapted plants, such as water plantain and water candle, are recommended. These plants are highly resistant to flooding and can maintain their ecological functions despite tidal fluctuations.

[0081] Plant Selection for the Third-Tier Circular Wetland: Functionally, the third-tier circular wetland, 300, is a deep-bed denitrifying wetland, subject to chronic waterlogging and anaerobic conditions. Plants must be tolerant to flooding and able to survive low dissolved oxygen environments. Their primary function is to provide a microenvironment for roots, enhancing denitrification while also absorbing pollutants through plant metabolism. Aquatic plants that tolerate long-term flooding and low oxygen levels, such as yellow iris and canna, were selected. These plants are highly resistant to stress and adapted to anaerobic wetland conditions, while also promoting denitrification through their root secretions.

[0082] Example 4:

[0083] Based on Example 1, 2, or 3, a sewage treatment method using the rotating tower multi-stage tidal flow artificial wetland system comprises the following steps:

[0084] S1. Sewage enters from the water inlet 111 of the central purification wetland 100;

[0085] S2, the sewage undergoes nitrification reaction in an aerobic environment from top to bottom and then enters the first water collection channel 120 from the bottom;

[0086] S3. The water in the first water collecting channel 120 flows from bottom to top into the first rotary drainer 130 and is discharged to the outer adjacent annular wetland surface in the form of a rotary waterfall;

[0087] S4. In this layer of annular wetland, water undergoes nitrification in an anoxic environment from top to bottom and then enters the second water collection channel 220 from the bottom;

[0088] S5. The water in the second water collecting channel 220 flows from bottom to top into the second rotary drainer 230 and is discharged to the outer adjacent annular wetland surface in the form of a rotary waterfall.

[0089] S6. Finally, the water is discharged to the outermost annular wetland surface in the form of a rotating waterfall. After nitrification treatment in an anaerobic environment from top to bottom, the water enters the drainage channel 320 from the bottom and is finally discharged from the drainage port 321.

[0090] Specifically, according to the design structure and function of the system, the operating parameters of each layer of wetlands determine the efficiency of sewage treatment and the denitrification effect.

[0091] Central Purification Wetland 100 operating parameters:

[0092] The hydraulic retention time (HRT) is set at 4-6 hours to ensure sufficient retention time within the wetland matrix for nitrification to complete. A downward vertical subsurface flow pattern is employed, with a flow rate of 0.1-0.3 m³ / h to ensure uniform vertical penetration. The surface dissolved oxygen concentration should be maintained at 4-6 mg / L to promote nitrification, while the bottom dissolved oxygen concentration should be controlled below 0.5 mg / L to initiate denitrification.

[0093] Second-layer circular wetland 200 operating parameters:

[0094] The tidal cycle is set to occur every 6 to 12 hours, and the periodic switching of the rotating overflow weir ensures that each sector module undergoes a complete cycle of water inflow, drainage, reoxygenation, and venting. The hydraulic retention time (HRT) is set at 3 to 5 hours, and the tidal flow periodically controls the water level to promote nitrification in the breathing zone and denitrification in the immersion zone. For water level regulation, the water level in the upper breathing zone should be controlled 10 to 20 cm below the wetland surface to avoid excessive immersion, while the lower immersion zone should remain fully submerged. The dissolved oxygen concentration in the breathing zone should be maintained at 2 to 4 mg / L to facilitate nitrification, while the dissolved oxygen in the immersion zone should be close to 0 mg / L to optimize denitrification.

[0095] The third layer of circular wetland 300 operating parameters:

[0096] The hydraulic retention time (HRT) is set at 5-8 hours. The third circular wetland, 300 meters in diameter, is primarily a deep-bed denitrification wetland. Longer retention times help improve denitrification efficiency. The flow rate should be controlled between 0.05 and 0.2 m³ / h to ensure a slow flow through the substrate, maximizing denitrification.

Claims

1. A rotating tower multi-stage tidal flow artificial wetland system, characterized by: The invention comprises a central purification wetland (100), wherein the central purification wetland (100) is surrounded by multiple layers of annular wetlands in descending order, wherein the annular wetlands of each layer are respectively composed of multiple fan-shaped purification units, a first water collection channel (120) is provided between the central purification wetland (100) and the adjacent annular wetlands, the bottom of the first water collection channel (120) is connected to the bottom of the central purification wetland (100), a second water collection channel (220) is provided for each of the fan-shaped purification units corresponding to the inner side between adjacent annular wetlands, the bottom of the second water collection channel (220) is connected to the bottom of the corresponding fan-shaped purification unit on the inner side, a drainage channel (320) is provided on the outer side of the outermost annular wetland, and a drainage outlet (321) is provided on the outer side of the upper end of the drainage channel (320); The central purification wetland (100) is provided with a water inlet (111) at the upper end, a first rotary drainer (130) is installed at the top of the first water collection channel (120), and a second rotary drainer (230) is installed at the top of the second water collection channel (220). The first rotary drainer (130) is used to drain water by a rotary waterfall to the top of the adjacent annular wetland, and the second rotary drainer (230) is used to drain water by a rotary waterfall to the top of the outer annular wetland. The second rotary drainer (230) comprises a first rotating ring (231), a second gear ring (236) and a second motor (237); a second water outlet (221) is provided on the second water collecting channel (220); a supporting ring (225) is fixedly installed on the outer wall of the annular wetland below the second water outlet (221); a rotating ring (235) is movably supported on the supporting ring (225); the first rotating ring (231) is installed on the rotating ring (235); a second gear ring (236) is also installed on the rotating ring (235); a second motor (237) is installed on the outer wall of the annular wetland; a second gear (238) is installed on the output shaft of the second motor (237); the second gear ring (236) and the second gear (238) are meshed and driven; at least one second water outlet pipe (234) is installed on the lower side of the first rotating ring (231); The second rotary drainer (230) further comprises a second rotary ring (232), the second rotary ring (232) being located above the first rotary ring (231), the bottom of the second rotary ring (232) being connected to a drain pipe (233), the drain pipe (233) passing through the first rotary ring (231) and being fixedly connected to the first rotary ring (231); A third water outlet (222) is further provided on the second water collecting channel (220) above the second water outlet (221). The third water outlet (222) is used to guide water into the second rotating ring (232). A first control valve (223) and a second control valve (224) are respectively installed on the second water outlet (221) and the third water outlet (222).

2. The rotating tower multi-stage tidal flow artificial wetland system according to claim 1 is characterized in that: The central purification wetland (100) comprises a central container (110), a water inlet (111) is arranged at the top of the central container (110), a first water collection channel (120) is arranged on the outer wall of the central container (110), and the central container (110) is filled with a first nitrification treatment matrix.

3. The rotating tower multi-stage tidal flow artificial wetland system according to claim 2 is characterized in that: The first nitrification treatment matrix is ​​provided with three layers, which are, from top to bottom, a porous light matrix (101), an aggregate matrix (102), and a denitrification matrix (103).

4. The rotating tower multi-stage tidal flow artificial wetland system according to claim 1, characterized in that: The first rotary drainer (130) comprises a rotary groove ring (131), a first gear ring (134) and a first motor (135), wherein a support ring (133) is fixedly mounted at the inner hole of the upper side of the rotary groove ring (131), a limit ring (112) is fixedly mounted at the top of the central purification wetland (100), the support ring (133) is movably sleeved on the outer side of the limit ring (112), the inner hole of the support ring (133) is mounted with the first gear ring (134), and the first motor ( 135) is installed on the top of the central purification wetland (100), the output shaft of the first motor (135) is installed with a first gear (136), and the first ring gear (134) is meshed with the first gear (136) for transmission; the outer side of the first water collection channel (120) is provided with a first water outlet (121), the first water outlet (121) extends into the rotating groove ring (131), and the lower side of the rotating groove ring (131) is installed with at least one first water outlet pipe (132).

5. The rotating tower multi-stage tidal flow artificial wetland system according to claim 1 is characterized in that: The fan-shaped purification unit located in the inner layer includes a first fan-shaped container (210), the top of the first fan-shaped container (210) is open, the outer wall of the first fan-shaped container (210) is provided with a second water collection channel (220), and the first fan-shaped container (210) is filled with a second nitrification treatment matrix.

6. The rotating tower multi-stage tidal flow artificial wetland system according to claim 5, characterized in that: The second nitrification treatment matrix is ​​provided with two layers, which are, from top to bottom, a porous matrix (201) and a denitrification enhancement matrix (202).

7. The rotating tower multi-stage tidal flow artificial wetland system according to claim 1, characterized in that: The fan-shaped purification unit located at the outermost layer includes a second fan-shaped container (310), the top of the second fan-shaped container (310) is open, the drainage channel (320) is arranged on the outer wall of the second fan-shaped container (310), and the second fan-shaped container (310) is filled with a functional matrix (301) that supplies organic electrons or inorganic electrons.

8. A sewage treatment method, characterized in that: A rotating tower multi-stage tidal flow artificial wetland system according to any one of claims 1 to 7 is used, and the treatment method comprises the following steps: S1, sewage enters from the water inlet (111) of the central purification wetland (100); S2, the sewage undergoes nitrification reaction in an aerobic environment from top to bottom and then enters the first water collection channel (120) from the bottom; S3, the water in the first water collection channel (120) flows from bottom to top into the first rotary drainer (130), and is then discharged to the outer adjacent annular wetland surface in the form of a rotary waterfall; S4. In the annular wetland, water undergoes nitrification from top to bottom in an anoxic environment and then enters the second water collection channel (220) from the bottom; S5, the water in the second water collection channel (220) flows from bottom to top into the second rotary drainer (230), and is then discharged to the outer adjacent annular wetland surface in the form of a rotary waterfall; S6. Finally, the water is discharged to the outermost annular wetland surface in the form of a rotating waterfall. After nitrification treatment in an anaerobic environment from top to bottom, the water enters the drainage channel (320) from the bottom and is finally discharged from the drain outlet (321).

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