Enhanced phosphorus and nitrogen removal wetland system suitable for rainwater discharge port pollution interception

Abstract

The utility model relates to the technical field of water environment restoration, and discloses an enhanced phosphorus and nitrogen removal wetland system suitable for intercepting pollution at a rainwater discharge port. The wetland system is arranged in a water area range on the outer side of the rainwater outlet and comprises five parts, namely a gravel area, a water guide channel, an aeration system, a plant filter bed and a tail end strengthening area; the gravel area is arranged on the outer side of the rainwater outlet, the water guide channel is connected with the gravel area and arranged at the rear end of the gravel area, the aeration system is installed in the water guide channel, the plant filter bed is arranged at the rear end of the water guide channel, and the tail end strengthening area is arranged on the outer side area of the plant filter bed. The enhanced phosphorus and nitrogen removal wetland system constructed by the utility model can effectively enhance the removal effect of nitrogen and phosphorus in initial rainwater, further reduce pollutants discharged into a water body, improve the landscape effect and the ecological appearance of a discharge port area, and can give consideration to better landscape property, ecological property and economical efficiency while having stronger functionality.

Description

Technical Field

[0001] The utility model belongs to the technical field of water environment restoration, and in particular relates to an enhanced phosphorus and nitrogen removal wetland system suitable for intercepting pollution at a rainwater outlet. Background Art

[0002] With the rapid development of urbanization, urban areas are expanding and impervious surfaces are increasing, resulting in a significant increase in surface runoff in urban areas. This change not only increases the risk of urban waterlogging, but also makes the initial rainwater discharged from the stormwater outlet one of the important sources of urban water pollution. The initial rainwater carries a large amount of pollutants such as suspended solids, nitrogen, phosphorus and organic matter, which will further increase the pollution load of urban rivers, lakes and other water bodies. Although traditional initial rainwater treatment methods, such as storage ponds, can reduce rainwater runoff pollution to a certain extent, these methods usually occupy a large area, have high investment and lack eco-friendliness. Ecological transformation of the outlet within the scope of river and lake waters, intercepting pollutants in the initial rain through ecological measures, can not only purify the initial rainwater, but also enhance the ecological function of the water body, promote biodiversity, and achieve sustainable development of the environment and society.

[0003] At present, there are some ecological transformation measures for outlets, which treat initial rainwater by setting up purification wetlands in the outlet area. Although these measures can purify the initial rainwater to a certain extent, it is often difficult to specifically remove nitrogen and phosphorus pollutants in the initial rainwater, which are the main factors affecting the water quality of most rivers and lakes. Utility Model Content

[0004] The purpose of the utility model is to overcome the deficiencies of the above-mentioned background technology, to enhance the removal of nitrogen and phosphorus in the initial rainwater in a targeted manner, to form the last pollution interception zone for the initial rainwater discharged into the water body, and to provide an enhanced phosphorus and nitrogen removal wetland system suitable for intercepting pollution at rainwater outlets.

[0005] The technical solution adopted by the utility model is: an enhanced phosphorus and nitrogen removal wetland system suitable for intercepting pollution at a rainwater outlet, the wetland system is arranged in the water area outside the rainwater outlet, and includes five parts: a gravel area, a water guide channel, an aeration system, a plant filter bed and a terminal enhanced area; the gravel area is arranged outside the rainwater outlet, the water guide channel is connected to the gravel area and arranged at the rear end of the gravel area, the aeration system is installed in the water guide channel, the plant filter bed is arranged at the rear end of the water guide channel, and the terminal enhanced area is arranged in the area outside the plant filter bed.

[0006] In the above scheme, the gravel area is composed of graded gravel to dissipate the energy of the incoming water and to protect the bottom of the outlet area to prevent rainwater from scouring and stirring the bottom to release pollutants. After the rainwater is pretreated in the gravel area, it is evenly distributed and diverted in the diversion channel. During the distribution and diversion, the rainwater is aerated and aerated in the diversion channel through the aeration system to increase the removal efficiency of ammonia nitrogen. After the rainwater is diverted into the plant filter bed through the diversion channel, the removal effect of ammonia nitrogen and total phosphorus is further enhanced through the combined action of plants, fillers and microorganisms. The fillers are mixed and arranged with ordinary fillers and functional fillers. The functional fillers are targeted to select types with good nitrogen and phosphorus adsorption effects. The rainwater purified by the plant filter bed finally enters the terminal reinforcement area. The artificial water plants and aerators in the terminal reinforcement area can further play a purification role and strengthen the reduction of nitrogen and phosphorus in the rainwater. The outermost ecological enclosure in the terminal reinforcement area can control the disorderly growth of floating leaf plants to the outside, and can also control the diffusion of pollutants in the rainwater to the outer water body, and make the rainwater evenly flow into the outer lake and river water body.

[0007] In a further preferred structure, the gravel area is paved with graded gravels of different particle sizes, and the particle sizes of the gravels are reversely graded from upstream to downstream.

[0008] In the above scheme, the gravel area is formed by natural gravel accumulation, the top surface elevation of the gravel area is not higher than the bottom elevation of the rainwater outlet, large-size gravel is used at the front end of the gravel area, and small-size gravel is used at the rear end. The reverse grading of particle size with large size at the front and small size at the back can improve the sedimentation and filtration effect and improve the pollutant removal rate.

[0009] A further preferred structure is that the water diversion channel uses a bed matrix of a plant filter bed adjacent to the water diversion channel to form a channel wall for water diversion, and the bottom of the water diversion channel is paved with 40-80 mm gravel.

[0010] In the above scheme, the diversion channel uses a plant filter bed bed matrix near the diversion channel to form the channel wall. Compared with the traditional channel wall structure, the channel wall structure formed by the filler is more ecological. In addition, the filler structure of the channel wall can also play the function of removing filler pollutants and enhance the total phosphorus removal effect. The filler particle size of the channel wall is 10-20mm, and the slope is sloped toward the diversion channel with a slope of 1:3. The top of the channel wall is flush with the normal water level.

[0011] In a further preferred structure, an aeration system is provided in the water channel, and the aeration system comprises a plug flow aerator and a submersible aeration facility, wherein the submersible aeration facility is installed along the entire water channel, and the plug flow aerator is installed intermittently.

[0012] In the above scheme, push flow aeration equipment is arranged at intervals along the diversion channel for oxygenation and diversion. Submersible aeration equipment is laid throughout the entire section for oxygenation and enhanced ammonia nitrogen removal.

[0013] In a further preferred structure, the bed matrix of the plant filter bed is made of gravel and functional fillers for absorbing nitrogen and phosphorus, and the plants are emergent plants.

[0014] In the above scheme, the bed matrix of the plant filter bed adopts gravel filler and functional fillers such as expanded clay, volcanic rock, zeolite, and steel slag to further enhance the removal effect of nitrogen and phosphorus. The filler particle size is 20 to 40 mm, and the top elevation of the filter bed is 20 cm lower than the normal water level. The plants used are pollution-resistant and flood-resistant varieties such as hydrangea, reed, and water candle.

[0015] A further preferred structure is that artificial aquatic plants are laid at the bottom of the terminal reinforcement area, floating leaf plants are planted on the upper part, a fountain aerator is installed, and an ecological enclosure is arranged on the outside, and the ecological enclosure adopts an enclosure with mesh holes.

[0016] In the above scheme, artificial water plants such as carbon fiber grass and ecological base are used in the terminal reinforcement area. Compared with aquatic plants, artificial water plants are not affected by high pollution loads and can stably perform the function of pollutant removal. In addition, artificial water plants can be used as fillers to further enhance the removal effect of various pollutants. Floating leaf plants such as water chestnuts and water turtles are planted on the water surface of the terminal reinforcement area. The aeration equipment uses a fountain aerator, and the ecological enclosure uses a 4-mesh polyethylene mesh.

[0017] The beneficial effects of the utility model are as follows: the utility model gives full play to the composite reduction effect of fillers, plants and microorganisms on pollutants by combining the gravel area, plant filter bed and terminal reinforcement area technology, and further enhances the removal effect of nitrogen and phosphorus in initial rainwater; through the combined arrangement of aeration equipment and diversion channel, the diversion water distribution and oxygenated aeration are coupled, which not only improves the diversion water distribution effect but also enhances the removal effect of organic matter and ammonia nitrogen; and functional fillers are added to the plant filter bed to specifically adsorb nitrogen and phosphorus, further enhancing the nitrogen and phosphorus removal effect.

[0018] The utility model has a simple structure, reasonable cost and convenient maintenance. On the basis of purifying initial rainwater and enhancing the ecological function of water bodies, it further improves the removal effect of nitrogen and phosphorus pollutants and can effectively ensure the water quality of rivers and lakes during rainfall. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a plan view of the utility model.

[0020] Figure 2 It is a schematic structural cross-sectional diagram of the water diversion channel and plant filter bed of the utility model.

[0021] Figure 3 It is a schematic cross-sectional view of the terminal reinforcement zone of the utility model.

[0022] In the figure, 1-gravel area, 2-water diversion channel (201-gravel), 3-aeration system (301-plug flow aerator, 302-submersible aeration facility), 4-plant filter bed (401-bed matrix, 402-emergent plants), 5-terminal reinforcement area (501-artificial aquatic plants, 502-floating leaf plants, 503-fountain aerator, 504-ecological enclosure), 6-river and lake water bodies. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but they do not constitute a limitation on the present invention.

[0024] like Figure 1 As shown, the present embodiment is an enhanced phosphorus and nitrogen removal wetland system suitable for intercepting rainwater outlet pollution, which consists of five parts: a gravel area 1, a water diversion channel 2, an aeration system 3, a plant filter bed 4 and a terminal enhanced area 5.

[0025] In this embodiment, the bottom elevation of the rainwater outlet A is above the normal water level of the lake. A gravel area 1 is arranged outside the rainwater outlet A. The total width of the gravel area 1 is 5m. The front end is paved with 80-120mm gravel and is 3m wide. The rear end is paved with 40-80mm gravel and is 2m wide. The top elevation of the gravel area 1 is flush with the bottom elevation of the rainwater outlet A. The incoming water can dissipate energy, settle sediment and be filtered in the gravel area 1. At the same time, the gravel area 1 is lower than the rainwater outlet A and will not affect the normal drainage of the rainwater outlet A. The rainwater enters the water diversion channel 2 after being pre-treated in the gravel area 1.

[0026] The water inlet end of the water channel 2 is connected to the gravel area 1. The water channel 2 is 1.5m wide and 40m long. Figure 2 As shown, the channel walls on both sides of the water diversion channel 2 are filled with the bed matrix 401 of the plant filter bed 4, with a particle size of 10-20 mm, which can guide water and remove pollutants at the same time; when filling the filler, the water diversion channel 2 is sloped with a slope of 1:3, and the top of the channel wall is flush with the normal water level; 40-80 mm gravel 201 is laid on the bottom of the channel, and the gravel 201 is laid with a thickness of 0.3 m. The water diversion channel 2 is 1.5 m deep below the normal water level to ensure that the cross-sectional size of the water passage is sufficient and does not affect drainage. An aeration system 3 is arranged in the water diversion channel 2, including a plug flow aerator 301 and a submerged aeration facilities 302 (aeration pipe + aeration plate). A plug flow aerator 301 is set every 10 m, pushing flow toward the downstream direction of the water diversion channel. The submerged aeration facilities 302 are laid along the bottom of the water diversion channel to oxygenate and aerate the rainwater, providing favorable conditions for subsequent pollutant removal. Rainwater is guided through the wall of the water diversion channel 2 and enters the plant filter bed 4 by overflow and seepage.

[0027] The bed matrix 401 of the plant filter bed 4 is composed of a 1:1 mixture of gravel and ceramsite fillers. The particle size of the fillers is 15 - 25 mm. The functional fillers with a small particle size can enhance the removal effect of nitrogen and phosphorus by the plant filter bed 4. The fillers are filled from the bottom of the lake to 0.2 m below the normal water level, providing suitable water depth conditions for the growth of emergent plants 402. The emergent plants 402 used in the plant filter bed 4 are Thalia dealbata and Typha angustifolia. Thalia dealbata and Typha angustifolia have tall plants, can adsorb more pollutants, are more flood-tolerant, and are easy to maintain. The rainwater is intensively treated in the plant filter bed 4 and then discharged into the terminal intensification area 5.

[0028] As Figure 3 shown, the arrow direction in the figure is the water flow direction. The artificial aquatic plants 501 in the terminal intensification area 5 use carbon fiber grass, which can increase the number of microbial attachments through a higher specific surface area and enhance the removal effect of nitrogen and phosphorus by the microbial action. The floating-leaved plants 502 on the water surface in the final section intensification area 5 use Nymphoides peltata, which improves the wetland ecology and further reduces pollutants through plant absorption. Three sets of fountain aerators 503 are installed in the terminal intensification area 5 to further increase oxygen aeration, enhance the removal effect of ammonia nitrogen, and also improve the landscape to a certain extent. The ecological enclosure 504 is arranged outside the terminal intensification area to control the spread of the floating-leaved plants 502 and slow down the outward diffusion of pollutants. The rainwater is finally purified in the terminal intensification area 5 and then flows into the outer water body.

[0029] The enhanced phosphorus and nitrogen removal wetland system constructed by the gravel area, water diversion channel, aeration system, plant filter bed and terminal intensification area of the present utility model can effectively enhance the removal effect of nitrogen and phosphorus in the initial rainwater, further reduce the pollutants discharged into the water body, and at the same time improve the landscape effect and ecological style of the outfall area. While having strong functionality, it can also take into account good landscape, ecology and economy.

[0030] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

Claims

1. An enhanced phosphorus and nitrogen removal wetland system suitable for intercepting rainwater outlet pollution, characterized in that: The wetland system is arranged in the water area outside the rainwater outlet (A), and includes five parts: a gravel area (1), a water channel (2), an aeration system (3), a plant filter bed (4) and a terminal reinforcement area (5); the gravel area (1) is arranged outside the rainwater outlet (A), the water channel (2) is connected to the gravel area (1) and arranged at the rear end of the gravel area (1), the aeration system (3) is installed in the water channel (2), the plant filter bed (4) is arranged at the rear end of the water channel (2), and the terminal reinforcement area (5) is arranged in the area outside the plant filter bed (4).

2. The enhanced phosphorus and nitrogen removal wetland system suitable for intercepting rainwater outlet pollution according to claim 1, characterized in that: The gravel area (1) is paved with graded gravels of different particle sizes, and the particle sizes of the gravels are reversely graded from upstream to downstream.

3. The enhanced phosphorus and nitrogen removal wetland system suitable for intercepting rainwater outlet pollution according to claim 1 is characterized by: The water diversion channel (2) uses a plant filter bed (4) adjacent to the water diversion channel (2) to form a channel wall for water diversion, and the bottom of the water diversion channel (2) is paved with 40-80 mm gravel (201).

4. The enhanced phosphorus and nitrogen removal wetland system suitable for intercepting rainwater outlet pollution according to claim 1 is characterized by: An aeration system (3) is provided in the water channel (2), wherein the aeration system (3) comprises a plug-flow aerator (301) and a submersible aeration facility (302), wherein the submersible aeration facility (302) is installed along the entire length of the water channel (2), and the plug-flow aerator (301) is installed intermittently.

5. The enhanced phosphorus and nitrogen removal wetland system suitable for intercepting rainwater outlet pollution according to claim 1 is characterized by: The bed matrix (401) of the plant filter bed (4) is made of gravel and functional fillers capable of absorbing nitrogen and phosphorus, and the plants are emergent plants (402).

6. The enhanced phosphorus and nitrogen removal wetland system suitable for intercepting rainwater outlet pollution according to claim 1, characterized in that: Artificial aquatic plants (501) are laid out at the bottom of the terminal reinforcement zone (5), floating leaf plants (502) are planted on the top, and a fountain aerator (503) is installed. An ecological enclosure (504) is arranged on the outside. The ecological enclosure (504) is an enclosure with mesh holes.

Images