A method for constructing a low-carbon landscape type ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies

Abstract

The application discloses a method for constructing a low-carbon landscape type ecosystem for reducing nitrogen and removing phosphorus of surface river and lake water bodies, which comprises the following steps: introducing the water body to be treated into a multifunctional diversion and sedimentation channel, an A-O improved wetland, an ecological conservation type wetland and a multistage A-O oxidation pond, and finally storing and recycling the treated water body in an ecological river and lake self-purification area. The multifunctional diversion and sedimentation channel is arranged to uniformly distribute the water body, reduce the content of silt and suspended solids in the water body, improve the purification capacity of the subsequent wetland and prevent the wetland from being blocked. The A-O improved wetland, the ecological conservation type wetland and the multistage A-O oxidation pond are connected in parallel to purify the water body step by step, improve the effect of reducing nitrogen and removing phosphorus of the water body, improve the impact resistance of the ecological system and facilitate the operation, maintenance and management in the later period. Meanwhile, various types of plants are planted, aquatic animals are released and waterfowl are attracted to create diversified ecological landscapes and improve the biodiversity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ecological restoration and water environment treatment, and particularly relates to a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in surface river and lake water bodies. BACKGROUND

[0002] Surface river and lake water bodies are carriers of urban development, important components of urban structure and life, and important components of urban resources and ecological environment, and most cities are built along the water. However, with the continuous development of cities, urban water bodies are facing serious problems such as water environmental pollution, water quality deterioration, sharp shortage of fresh water resources, serious damage to water ecological systems, and lack of biological diversity. On the other hand, with the development of cities and the continuous improvement of urbanization level, people's requirements for urban water quality and ecological environment are also increasing. Therefore, how to handle the water environment protection problem in the development process, improve the water quality of surface river and lake water bodies in the basin, improve the water ecological environment quality, enhance the water landscape, improve the biological diversity, and reduce carbon emissions and improve the utilization rate of surface river and lake water resources have become a hot issue of concern in today's society.

[0003] For surface river and lake water bodies, they often face point, surface and endogenous pollution. Although most areas at this stage adopt rain and sewage separation drainage system, affected by the over-standard water body discharge of drainage outlets, the initial rainwater runoff of rainwater pipes, and the inflow of combined sewage in old urban areas, point source pollution is still one of the main reasons for the pollution of surface river and lake water bodies. The large-scale use of fertilizers and pesticides in agricultural production has accelerated the process of water environmental pollution and eutrophication to some extent, and the concentration of nitrogen and phosphorus nutrients in farmland runoff is often high. During the rainfall and irrigation process, the nutrients carried by the farmland runoff flow into nearby rivers or lake water bodies, causing serious agricultural non-point source pollution. In addition, the sediment sludge at the bottom of the surface river and lake water body is easy to release pollutants into the overlying water, forming endogenous pollution. However, the self-purification ability of the present river and lake water body is lacking, and the water quality of most river and lake surface water bodies is lower than the quality requirements of urban water environmental function zoning, and there are often problems of excessive nitrogen and phosphorus nutrients.

[0004] The surface river and lake water bodies of inferior V type are often treated by physical, chemical or biological technology. However, the conventional physical and chemical treatment method often has problems such as high power consumption of equipment, secondary pollution caused by the addition of chemical agents, complex maintenance in the later period, etc. Or the conventional ecological treatment technology often has problems such as single technology, imperfect drainage system, poor water resistance, poor landscape effect, etc. SUMMARY

[0005] The present application aims to overcome the deficiencies in the prior art and provide a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in surface river and lake water bodies.

[0006] In order to achieve the above-mentioned purpose of the application, the technical scheme provided by the present application is as follows:

[0007] A method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in surface river and lake water bodies, which specifically comprises the following steps:

[0008] Firstly, according to the target discharge water volume of the treated water body, the water supplement volume calculated based on the water balance in the site, and a proper adjustment coefficient, the total treatment scale of the ecological system is determined; the water quality of the water body to be treated is determined; and the water quality target after treatment is determined.

[0009] Secondly, the water body to be treated is introduced into a multifunctional diversion and sedimentation channel to perform sedimentation treatment on the silt and suspended matter in the water body.

[0010] Thirdly, the water body treated by the multifunctional diversion and sedimentation channel is introduced into an A-O improved wetland to perform nitrogen reduction and phosphorus removal purification treatment on the water body.

[0011] Fourthly, the water body purified by the A-O improved wetland is introduced into an ecological conservation wetland to remove nitrogen and phosphorus nutrients in the water body by laying water purification filter material in the ecological conservation wetland, and to create various terrains and natural habitats in the ecological conservation wetland to enrich biological diversity.

[0012] Fifthly, the water body purified by the ecological conservation wetland is introduced into a multi-stage A-O oxidation pond to further perform nitrogen reduction and phosphorus removal purification treatment on the water body.

[0013] Sixthly, the water body treated by the multi-stage A-O oxidation pond is introduced into an ecological river and lake self-purification area to realize in-situ purification of the incoming water by constructing a stable aquatic plant purification system and an aquatic animal regulation system, and to complete the nitrogen reduction and phosphorus removal purification target of the surface river and lake water body and water recycling by purifying the water introduced into the ecological river and lake self-purification area for reuse.

[0014] The total treatment scale W of the ecological system calculated in the first step z is the target discharge water volume of the treated water body Q p , the sum of the water supplement volume W calculated based on the water balance in the site, and multiplied by a proper adjustment coefficient k, i.e. W z =k*(Q p +W); the adjustment coefficient is comprehensively valued according to the comprehensive land use index of the site and the local rainfall condition, and is 1.1-1.3; and the specific calculation formula of the water supplement volume is:

[0015] W=Q l +Q r +q1-q2-q3, wherein W is the water supplement volume; Ql Q is the irrigation amount of landscape greening r Q1 is the lake bottom leakage amount of the water purification unit; q1 is the water evaporation amount; q2 is the water surface precipitation amount; q3 is the surface runoff amount; the irrigation amount of landscape greening includes the greening and road irrigation amount.

[0016] The specific calculation formula of the lake bottom leakage amount of the water purification unit is Q r = KJA s T s , wherein Q r is the infiltration amount m 3 ; K is the infiltration coefficient, m / s; J is the hydraulic slope, and the value of J is 1; A s is the effective infiltration area m 2 ; T s is the infiltration time s.

[0017] The water quality determination method of the water body to be treated is as follows: when the water quality index of the water to be treated is clear, the water quality of the water to be treated is determined according to the water quality index; when the water quality of the water to be treated is an unstable water body, the water quality index of the water to be treated is determined after sampling and detection, and the sampling and detection method of the water quality of the water to be treated is performed according to the requirements of the Water Quality Sampling Technology Guide (HJ494-2009) and the Surface Water and Sewage Monitoring Technical Specification (HJ / T91-2002).

[0018] The multifunctional shunt sedimentation channel in the second step is in a long strip type, the main structure adopts rubble retaining wall masonry, the bottom is laid with 500mm planting soil after anti-seepage treatment, the bottom of the pond is sloped at 4‰ from the water inlet end to the water outlet end, and is sequentially scattered with gravel, planted with chrysanthemum grass and goldfish algae, and stacked with a volcanic rock cage filter tank, so that the sediment and suspended matter in the surface river and lake water body are treated, the sediment and suspended matter content in the water inlet of the A-O improved wetland at the rear end is reduced, the purification effect of the A-O improved wetland can be improved, and the blockage is reduced. In order to realize uniform water distribution, the multifunctional shunt sedimentation channel is used for grading and shunting water distribution, and a sludge discharge suction system is arranged at the lower part.

[0019] The multifunctional shunt sedimentation channel is provided with a rubble retaining wall structure on both sides, the slope ratio of the retaining wall structure is 10:1, and waterproof mortar is arranged on the inner side of the retaining wall structure; the bottom of the multifunctional shunt sedimentation channel is laid with an HDPE geomembrane for anti-seepage treatment, a fine sand leveling layer is arranged at the bottom of the HDPE geomembrane, the bottom of the fine sand leveling layer is rammed with plain soil, a fine sand leveling layer is arranged at the upper part of the HDPE geomembrane, and a planting soil layer is arranged at the upper part of the fine sand leveling layer; a concrete coping is arranged at the upper end of the retaining wall structure, a concrete foundation is arranged at the bottom end of the retaining wall structure, and a plain concrete cushion layer is arranged at the lower end of the concrete foundation.

[0020] The HDPE geomembrane laid at the bottom of the multifunctional diversion sedimentation channel has a thickness of 0.5 mm, the fine sand leveling layer has a thickness of 100 mm, the planting soil layer has a thickness of 500 mm, the compaction degrees of the planting soil layer and the plain soil are both greater than 0.93, the waterproof mortar has a thickness of 30 mm, the concrete pressure top has a thickness of 100 mm, the concrete foundation has a thickness of 200 mm, and the plain concrete cushion layer has a thickness of 100 mm.

[0021] A water source access main water inlet pipe is arranged on the retaining wall structure of one side of the multifunctional diversion sedimentation channel, the main water inlet pipe is arranged according to the total treatment scale of the ecological system and the diversion arrangement of the diversion sedimentation channel, so as to ensure that the water flow velocity in the channel is 0.15-0.30 m / s and the residence time is 45-60 s; pebbles are laid at the bottom of the water inlet end of the multifunctional diversion sedimentation channel to buffer the water inlet of the multifunctional diversion sedimentation channel; and a water outlet pipe is arranged at the water outlet end of the multifunctional diversion sedimentation channel and is connected with the A-O improved wetland water inlet channel.

[0022] The A-O improved wetland in the third step comprises an anaerobic subsurface wetland treatment area and an oxygen-rich submerged plant surface flow wetland treatment area; the anaerobic subsurface wetland adopts a horizontal flow form, and the sewage is purified through the physical, chemical and biological effects of the filler bed, plants and microorganisms in the wetland; the water body in the anaerobic subsurface wetland flows at the bottom of the soil, and is prone to be anoxic, so the submerged plant surface flow wetland treatment area is arranged at the rear end of the anaerobic subsurface wetland; the submerged plant surface flow wetland treatment area mainly plants Vallisneria spinulosa and Hydrilla verticillata, the roots of the Vallisneria spinulosa and Hydrilla verticillata are embedded in the mud, and the whole plant is submerged under the water surface, the root system and the whole leaf surface of the submerged plant directly absorb the nutrients in the water body and silt, the required carbon source is directly absorbed from the water body, and the O2 produced by photosynthesis is directly dissolved in the water, so that the water body oxygen enrichment target can be achieved.

[0023] The anaerobic subsurface wetland treatment area and the oxygen-rich submerged plant surface flow wetland treatment area are sloped according to the water flow direction, and the longitudinal slope i is 1‰-5‰; the anaerobic subsurface wetland treatment area comprises a water distribution channel, a water inlet area, a purification area, a water outlet area and a water collection channel; the purification area is respectively provided with the water inlet area and the water outlet area at the two sides, the water inlet area is communicated with the water distribution channel, the water distribution channel is connected with the multifunctional diversion sedimentation channel through a water distribution pipe, and a valve well is arranged on the water distribution pipe; a stop valve and a check valve are arranged in the valve well; the water outlet area is connected with the water collection channel, the water collection channel is provided with a water outlet pipe, and the water outlet pipe is communicated with the oxygen-rich submerged plant surface flow wetland treatment area.

[0024] The water distribution channel is connected with the water distribution pipe at one end and with the water inlet area at the other end, a 1500mm-thick paddle-shaped stone retaining wall is arranged at the end of the water distribution channel connected with the water distribution pipe, a water distribution flower wall is arranged at the end of the water distribution channel connected with the water inlet area, the thickness of the water distribution flower wall is 1200mm, the opening rate of the water distribution flower wall is 30%, the aperture of the water distribution flower wall is 115*53mm, and a stainless steel mesh is arranged on the side of the water distribution flower wall close to the water inlet area; the water in the multifunctional diversion and sedimentation channel enters the water distribution channel through the water distribution pipe and then enters the water inlet area through the water distribution flower wall; a cover plate is arranged at the upper end of the water distribution channel, and the cover plate is made of 150mm-thick reinforced concrete.

[0025] The water inlet area is filled with gravel and volcanic rock mixed fillers, the width of the mixed fillers is 1m, the particle size of the gravel is 15-25mm, the particle size of the volcanic rock is 10-80mm, and the void ratio of the mixed fillers is 40%-50%.

[0026] The water outlet area is filled with gravel and volcanic rock mixed fillers, the width of the gravel and volcanic rock mixed fillers is 0.8m, the particle size of the gravel is 10-15mm, the particle size of the volcanic rock is 10-80mm, the void ratio of the mixed fillers is 30%-35%, one side of the water outlet area is connected with the water collection channel, the water collection channel comprises a water collection flower wall and an outlet pipe, the water collection flower wall is connected with the water outlet area, the opening rate of the water collection flower wall is 30%, the aperture of the water collection flower wall is 115*53mm, and a stainless steel mesh is arranged between the water collection flower wall and the water outlet area; the water collection channel is further provided with an outlet pipe, the outlet pipe is connected with the water collection channel, the outlet pipe is an adjustable outlet pipe, and the outlet pipe is used for adjusting the water level in the A-O improved wetland; a submerged pump is arranged between the anaerobic subsurface flow wetland and the oxygen-enriched submerged plant surface flow wetland, and the effluent of the oxygen-enriched submerged plant surface flow wetland treatment area is used for backwashing the anaerobic subsurface flow wetland treatment area.

[0027] The oxygen-enriched submerged plant surface flow wetland treatment area is provided with riprap at the water inlet end and is provided with a planting soil layer at the bottom, a 0.5mm HDPE geomembrane is arranged at the bottom end of the planting soil layer, plain soil is arranged at the bottom of the HDPE geomembrane, the thickness of the planting soil layer is 500mm, Vallisneria spinulosa and Hydrilla verticillata are planted on the planting soil layer in sequence, the compactness of the plain soil is greater than 0.93, and a waterfall wall is arranged at the water outlet end of the oxygen-enriched submerged plant surface flow wetland treatment area.

[0028] The upper end of the water inlet area, the purification area and the water outlet area is provided with a planting soil layer, the planting soil layer is used for planting plants, the thickness of the planting soil layer is 200-300 mm, the bottom of the planting soil layer is provided with a geotextile, the density of the geotextile is 200 g / m2, the purification area is filled with modified zeolite filler, the lower end of the modified zeolite filler, the lower end of the water inlet area and the lower end of the water outlet area are paved with a fine sand leveling layer, the lower end of the fine sand leveling layer is paved with an HDPE geomembrane, the lower end of the HDPE geomembrane is paved with a fine sand leveling layer, the lower end of the fine sand leveling layer is plain soil, the compaction degree of the plain soil is greater than 0.93, the particle size of the modified zeolite filler is 4-8 mm, the thickness of the modified zeolite filler is 1200 mm, the thickness of the HDPE geomembrane is 0.5 mm, and the thickness of the fine sand leveling layer is 100 mm.

[0029] The ecological conservation wetland in the fourth step is formed by terrain, is set as a deep pool and a shallow pool, creates a natural habitat, plants multiple types of plants, raises aquatic animals, and enriches biological diversity.

[0030] The terrain is provided with multiple grooves, the grooves near the water inlet end and the water outlet end of the ecological conservation wetland are paved with modified zeolite, the secondary grooves near the water inlet end and the water outlet end are paved with denitrification type biological filter material on both sides, the central groove of the ecological conservation wetland is paved with composite biological filler on one side and is paved with a stone cage fish nest at the bottom on the other side, the ecological conservation wetland is sequentially planted with purple yam, water chestnut, Chinese senna or canna, purple yam, elodea, mulberry, vetiver, and needle rush from the water inlet end to the central groove.

[0031] The multi-stage A-O type oxidation pond in the fifth step includes a floating leaf plant pond and a emergent plant pond, the floating leaf plant pond and the emergent plant pond are connected in series and are connected through a drop form, and multiple stages are arranged; the water inlet end of the first-stage floating leaf plant pond of the multi-stage A-O type oxidation pond is connected with the water outlet end of the ecological conservation wetland through a connecting pipe, and the water outlet end of the last-stage emergent plant pond of the multi-stage A-O type oxidation pond is connected with the ecological river and lake self-cleaning area.

[0032] The length-width ratio of the floating leaf plant pond and the emergent plant pond is 4:1; the effective water depth of the floating leaf plant pond is 1200-1500 mm, the sludge layer is 200 mm, and the super height is 300-500 mm; the effective water depth of the emergent plant pond is 300-500 mm, the sludge layer is 100 mm, and the super height is 300 mm; the hydraulic retention time of the floating leaf plant pond is 15 days, and the hydraulic retention time of the emergent plant pond is 10 days.

[0033] The water inlet pipe is arranged at the water inlet end of the emergent plant pond, and is communicated with the water outlet pipe of the ecological conservation type wetland, and the bottom of the water inlet end is provided with riprap, and the water outlet end is provided with a drop wall; the bottom of the emergent plant pond is provided with a planting soil layer, the bottom end of the planting soil layer is provided with a 0.5mm HDPE geomembrane, the bottom of the HDPE geomembrane is provided with plain soil, the thickness of the planting soil layer is 500mm, and the compaction degree of the plain soil is greater than 0.93; evergreen iris and arrowhead are planted on the upper portion of the water inlet end of the emergent plant pond, and the upper end of the planting soil layer in the emergent plant pond is planted with duckweed and water lily.

[0034] The water inlet end of the emergent plant pond is provided with a drop wall, and the water outlet end is provided with a water outlet pipe and riprap; the bottom of the emergent plant pond is provided with a planting soil layer, the bottom end of the planting soil layer is provided with a 0.5mm HDPE geomembrane, the bottom of the HDPE geomembrane is provided with plain soil, the thickness of the planting soil layer is 500mm, and the compaction degree of the plain soil is greater than 0.93; the water inlet end of the emergent plant pond is planted with umbrella grass, and the water outlet end is planted with alisma orientale.

[0035] The bottom of the ecological river and lake self-purification area in the sixth step is provided with a planting soil layer, the thickness of the planting soil layer is 500mm, the upper end of the planting soil layer is a constant water level area, the center water depth is 1500-3000mm, and the bottom end of the planting soil layer is provided with anti-seepage treatment measures according to actual conditions and local conditions. The middle part of the ecological river and lake self-purification area is selectively planted with a Vallisneria natans, Najas minor, Najas graminea, Potamogeton crispus and Hydrilla verticillata community on the planting soil layer, and the shore zone around the ecological river and lake self-purification area is sequentially planted with a Scortum latifolium, Iris, Lythrum salicaria community and dwarf cold-tolerant Vallisneria. The water inlet end of the ecological river and lake self-purification area is provided with riprap. Aquatic animals including fish, snails, shrimps, shellfish and plankton are put into the ecological river and lake self-purification area.

[0036] The recycled water after purification specifically includes water for greening irrigation, water for road washing, and water for supplementing surrounding landscape water bodies.

[0037] Based on the technical scheme, the method for constructing a low-carbon landscape type ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies has the following technical advantages:

[0038] 1. The method for constructing a low-carbon landscape type ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies, by designing a combined ecological purification system combining a multifunctional diversion and sedimentation channel, an A-O improved wetland, an ecological conservation type wetland, a multi-stage A-O type oxidation pond and an ecological river and lake self-purification area, achieves the water quality purification target of reducing nitrogen and phosphorus in surface river and lake water bodies, and through planting of multiple types of plants, putting of aquatic animals and attracting of waterfowl, a diversified ecological landscape is created, and biological diversity is improved.

[0039] 2. The method for constructing a low-carbon landscape ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies, wherein A-O improved wetlands, ecological conservation wetlands, and multi-stage A-O oxidation ponds are arranged in parallel to improve the impact resistance of the ecological system and facilitate later operation, maintenance, and management.

[0040] 3. The method for constructing a low-carbon landscape ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies, wherein the design of a multifunctional diversion and sedimentation channel can achieve sediment and suspended matter precipitation treatment in the surface river and lake water bodies, reduce the sediment and suspended matter content in the water entering the A-O improved wetlands, improve the purification effect of the A-O improved wetlands, and reduce blockage.

[0041] 4. The method for constructing a low-carbon landscape ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies, wherein the design of the A-O improved wetlands increases the dissolved oxygen content in the system in an ecological manner and improves the nitrogen and phosphorus reduction capacity of the system. A backwashing system is arranged to directly use the wetland effluent for backwashing, thereby reducing the use of tap water, increasing the service life of the wetland, achieving the low-carbon emission reduction target, and adjusting the water level elevation and emptying of the A-O improved wetlands through the adjustable effluent pipe arranged at the A-O improved wetland effluent outlet, thereby improving the water quality purification capacity of the A-O improved wetlands and adjusting the water quantity entering the collecting channel from the A-O improved wetlands.

[0042] 5. The method for constructing a low-carbon landscape ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies, wherein the design of the ecological conservation wetlands uses the water purification filter material laid in the wetlands to remove nitrogen and phosphorus nutrients in the water body and creates various terrains in the ecological conservation wetlands to improve biodiversity.

[0043] 6. The method for constructing a low-carbon landscape ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies, wherein the design of the multi-stage A-O oxidation ponds achieves the biological nitrogen and phosphorus removal target through different water depth designs and different life form aquatic plant planting and creates different aquatic ecological landscapes; the multi-stage oxidation ponds are arranged to purify the water body in stages, promote the nitrification / denitrification of nitrogen and the sedimentation of phosphorus, and improve the effect of reducing nitrogen and phosphorus in the water body.

[0044] 7. The method for constructing a low-carbon landscape ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies, wherein the design of the ecological river and lake self-cleaning area achieves in-situ purification of the incoming water, purifies the water flowing into the ecological river and lake self-cleaning area, and realizes the surface river and lake water body nitrogen and phosphorus reduction and purification target and water recycling. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is a system arrangement drawing in the method for constructing a low-carbon landscape ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies.

[0046] Figure 2 is a horizontal section view of a multifunctional diversion sediment channel in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body.

[0047] Figure 3 is a plan view of an anaerobic subsurface flow wetland in an A-O improved wetland in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body.

[0048] Figure 4 is a section view of an anaerobic subsurface flow wetland in an A-O improved wetland in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body.

[0049] Figure 5 is a section view of an oxygen-rich submerged plant surface flow wetland in an A-O improved wetland in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body.

[0050] Figure 6 is a section view of an ecological conservation type wetland in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body.

[0051] Figure 7 is a section view of a floating leaf plant pond in a multi-stage A-O type oxidation pond in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body.

[0052] Figure 8 is a section view of an emergent plant pond in a multi-stage A-O type oxidation pond in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body.

[0053] Figure 9 is a section view of an ecological river and lake self-cleaning area in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body.

[0054] Figure 10 is a water body purification flow chart in a method for constructing a low-carbon landscape type ecological system for reducing nitrogen and removing phosphorus in a surface river and lake water body. DETAILED DESCRIPTION

[0055] To make the purpose, technical solution and advantages of the present application clearer and more explicit, the present application will be described below through specific examples shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0056] As Figures 1-10The present application belongs to a method for constructing a low-carbon landscape ecological system for reducing nitrogen and removing phosphorus in surface river and lake water bodies, as shown in the accompanying drawings Figure 1 The method specifically comprises the following steps:

[0057] In the first step, the total treatment scale of the ecological system is determined according to the target discharge water volume of the treated water body, the calculated water supplement volume based on the water balance in the site, and a proper adjustment coefficient; the water quality of the water body to be treated is determined; and the water quality target after treatment is determined.

[0058] In the second step, the water body to be treated is introduced into the multifunctional diversion and sedimentation channel 1 to realize uniform water distribution and to carry out sedimentation treatment on the silt and suspended substances in the water body.

[0059] In the third step, the water body treated by the multifunctional diversion and sedimentation channel 1 is introduced into the A-O improved wetland 2-3 to carry out nitrogen reduction and phosphorus removal purification treatment on the water body by the A-O improved wetland 2-3.

[0060] In the fourth step, the water body purified by the A-O improved wetland 2-3 is introduced into the ecological conservation wetland 4 to remove the nitrogen and phosphorus nutrients in the water body by the water purification filter material laid in the ecological conservation wetland 4, and to create various terrains and natural habitats in the ecological conservation wetland 4 to enrich the biodiversity.

[0061] In the fifth step, the water body purified by the ecological conservation wetland 4 is introduced into the multi-stage A-O oxidation pond 5-6 to further carry out nitrogen reduction and phosphorus removal purification treatment on the water body.

[0062] In the sixth step, the water body treated by the multi-stage A-O oxidation pond 5-6 is introduced into the ecological river and lake self-purification area 7, and the water in the ecological river and lake self-purification area 7 is purified in situ by the stable aquatic plant purification system and the aquatic animal control system to realize water purification and recycling, and to achieve the goal of reducing nitrogen and removing phosphorus in the surface river and lake water bodies and recycling the water bodies.

[0063] The total treatment scale W of the ecological system calculated in the first step is z the target discharge water volume Q of the treated water body p , the sum of the calculated water supplement volume W based on the water balance in the site, and multiplied by a proper adjustment coefficient k, i.e. W z =k*(Q p +W); the adjustment coefficient is comprehensively valued according to the comprehensive land use index of the site and the local rainfall condition, and is 1.1-1.3; and the specific calculation formula of the water supplement volume is:

[0064] W=Q l +Q r +q1-q2-q3, wherein W is the water supplement volume; Q l is the landscape greening irrigation volume; Qr Q1 is the lake bottom leakage amount of the water purification unit; q1 is the evaporation water amount; q2 is the water surface precipitation amount; q3 is the surface runoff amount; and the landscape greening irrigation amount includes greening and road irrigation amounts.

[0065] The specific calculation formula of the lake bottom leakage amount of the water purification unit is Q r = KJA s T s , wherein Q r is the infiltration amount m 3 ; K is the infiltration coefficient, m / s; J is the hydraulic slope, and the value of J is 1; A s is the effective infiltration area m 2 ; T s is the infiltration time s.

[0066] The water quality determination method of the water body to be treated is as follows: when the water quality index of the water to be treated is clear, the water quality of the water to be treated is determined according to the water quality index; when the water quality of the water to be treated is an unstable water body, the water quality index of the water to be treated is determined through sampling detection, and the sampling detection method of the water quality of the water to be treated is performed according to the requirements of the Water Quality Sampling Technology Guide (HJ494-2009) and the Technical Code for Monitoring of Surface Water and Sewage (HJ / T91-2002).

[0067] As shown in FIG. Figure 2 , the multifunctional shunt sedimentation ditch 1 in the second step is in a long strip type, the main structure is built by rubble retaining wall 113, the bottom is laid with 500mm-thick planting soil 121 after anti-seepage treatment, the bottom of the pond is sloped at 0.4% from the water inlet end to the water outlet end, and is sequentially spread with pebbles 131, planting chrysanthemum grass 132 and goldfish algae 133, and stacked with a volcanic rock cage filter tank 134, so as to realize the sedimentation treatment of the silt and suspended matter in the surface river and lake water body, reduce the silt and suspended matter content in the water inlet of the A-O improved wetland 2, improve the purification effect of the A-O improved wetland 2, and reduce the blockage. The pebbles 131 are spread on the bottom of the water inlet end, so as to realize the buffering and energy dissipation of the incoming water and reduce the scouring of the bottom of the pond; in order to realize the uniform water distribution, the multifunctional shunt sedimentation ditch is used for grading and shunting water distribution, and a sludge discharge pumping system is arranged at the lower part.

[0068] The multifunctional diversion and sedimentation channel 1 is provided with a rubble retaining wall 113 on both sides, the slope ratio of the retaining wall structure 113 is 10:1, and waterproof mortar 114 is arranged on the inner side of the retaining wall structure 113; the bottom of the multifunctional diversion and sedimentation channel 2 is paved with HDPE geomembrane 123 for anti-seepage treatment, the bottom of the HDPE geomembrane 123 is provided with a fine sand leveling layer 124, the bottom of the fine sand leveling layer 124 is rammed with plain soil 125, the upper part of the HDPE geomembrane 123 is provided with a fine sand leveling layer 122, and the upper part of the fine sand leveling layer 122 is provided with a planting soil layer 121; the upper end of the retaining wall structure 113 is provided with a concrete coping 115, the bottom end of the retaining wall structure 113 is provided with a concrete foundation 112, and the lower end of the concrete foundation 112 is provided with a plain concrete cushion layer 111.

[0069] The thickness of the HDPE geomembrane 123 paved at the bottom of the multifunctional diversion and sedimentation channel 1 is 0.5 mm, the thicknesses of the fine sand leveling layers 122 and 124 are 100 mm, the thickness of the planting soil 121 is 500 mm, the compactnesses of the planting soil layer 121 and the plain soil 125 are both greater than 0.93; the thickness of the waterproof mortar 114 is 30 mm, the thickness of the concrete coping 115 is 100 mm, the thickness of the concrete foundation 112 is 200 mm, and the thickness of the plain concrete cushion layer 111 is 100 mm.

[0070] The retaining wall structure on one side of the multifunctional diversion and sedimentation channel 1 is provided with a water source access main water inlet pipe 141, the main water inlet pipe 141 is arranged according to the total processing scale of the ecological system and the diversion and sedimentation channel, so as to ensure that the water flow velocity in the channel is 0.15-0.30 m / s and the residence time is 45-60 s; the bottom of the water inlet end of the multifunctional diversion and sedimentation channel is paved with pebbles 131 to buffer the water inlet of the multifunctional diversion and sedimentation channel. The water outlet end of the multifunctional diversion and sedimentation channel is provided with a water outlet pipe 142 connected with the A-O improved wetland water inlet channel 23.

[0071] As Figure 3 , Figure 4 and Figure 5As shown in the third step, the A-O improved wetland 2-3 includes an anaerobic subsurface flow wetland treatment area 2 and an oxygen-rich submerged plant surface flow wetland treatment area 3. The anaerobic subsurface flow wetland 2 adopts a horizontal flow form, and the sewage is purified through the physical, chemical and biological effects of the filler bed, plants and microorganisms in the wetland. The water in the anaerobic subsurface flow wetland 2 flows at the bottom of the soil, and is prone to be anoxic. Therefore, the oxygen-rich submerged plant surface flow wetland treatment area 3 is arranged at the rear end of the anaerobic subsurface flow wetland 2. The oxygen-rich submerged plant surface flow wetland treatment area 3 mainly plants Vallisneria spinulosa 33 and Hydrilla verticillata 34. The roots of the Vallisneria spinulosa 33 and Hydrilla verticillata 34 are embedded in the mud, and the whole plant is submerged under the water surface. The roots and the whole leaf surface of the submerged plant directly absorb the nutrients in the water and the sludge, and the required carbon source is directly absorbed from the water. The O2 produced by photosynthesis is directly dissolved in the water, and the water oxygen enrichment goal can be achieved.

[0072] The anaerobic subsurface flow wetland treatment area 2 and the oxygen-rich submerged plant surface flow wetland treatment area 3 are sloped according to the water flow direction, and the longitudinal slope i is 1‰-5‰. The anaerobic subsurface flow wetland treatment area 2 includes a water distribution channel 23, an inlet area 21, an outlet area 22, a water collection channel 26 and a purification area 27. The inlet area 21 and the outlet area 22 are arranged on the two sides of the purification area 27, respectively. The inlet area 21 is communicated with the water distribution channel 23 through a water distribution flower wall 232. The water distribution channel 23 is connected with the multifunctional shunt sedimentation channel 1 through a water distribution pipe 24. The water distribution pipe 24 is provided with a valve well 25. The valve well 25 is provided with a stop valve 251 and a check valve 252. The outlet area 22 is connected with the water collection channel 26 through a water collection flower wall 261. The water collection channel 26 is provided with an outlet pipe 262. The outlet pipe 262 is communicated with the oxygen-rich submerged plant surface flow wetland treatment area 3.

[0073] One end of the water distribution channel 23 is connected with the water distribution pipe 24, and the other end of the water distribution channel 23 is connected with the inlet area 21. The one end of the water distribution channel 23 connected with the water distribution pipe 24 is provided with a 1500mm-thick paddle stone retaining wall 231. The one end of the water distribution channel 23 connected with the inlet area 21 is provided with a water distribution flower wall 232. The thickness of the water distribution flower wall 232 is 1200mm. The opening rate of the water distribution flower wall 232 is 30%. The aperture of the water distribution flower wall 232 is 115*53mm. The water distribution flower wall 232 close to the inlet area 21 is provided with a stainless steel mesh 233. The water in the multifunctional shunt sedimentation channel 1 enters the water distribution channel 23 through the water distribution pipe 24, and then enters the inlet area 21 through the water distribution flower wall 232. The upper end of the water distribution channel 23 is provided with a cover plate 234. The cover plate 234 is made of 150mm-thick reinforced concrete.

[0074] The water inlet of the A-O improved wetland is connected to the front water distribution channel 23 through the water distribution pipe 24. A valve well 25 is arranged on each water distribution pipe 24. A stop valve 251 and a check valve 252 are arranged in the valve well 25. The water outlet in the multifunctional shunt sedimentation channel is distributed to the front water distribution channel 23 of the anaerobic subsurface flow wetland treatment area 2 in the A-O improved wetland through gravity pipe. Then, the water is distributed to the front water distribution area 21 of the purification area of the anaerobic subsurface flow wetland treatment area 2 in the A-O improved wetland through the water distribution flower wall 232, so that the water inlet is uniformly distributed to the entire purification bed. The length of the water distribution flower wall 232 is the same as the width of the anaerobic subsurface flow wetland treatment area 2. The opening rate of the water distribution flower wall 232 is 30%, and the hole diameter is 115*53 mm. A stainless steel mesh with a mesh size of 2*2 is arranged outside the hole to prevent blockage.

[0075] The gravel and volcanic rock mixed filler in the water inlet area 21 has a width of 1 m. The particle size of the gravel is 15-25 mm, the particle size of the volcanic rock is 10-80 mm, and the void ratio of the mixed filler is 40%-50%, which ensures uniform water distribution and prevents blockage.

[0076] The gravel and volcanic rock mixed filler in the water outlet area 22 has a width of 0.8 m. The particle size of the gravel is 10-15 mm, the particle size of the volcanic rock is 10-80 mm, and the void ratio of the mixed filler is 30%-35%. One side of the water outlet area 22 is connected to the water collection channel 26. The water collection channel 26 includes a water collection flower wall 261 and a water outlet pipe 262. The water collection flower wall 261 is connected to the water outlet area 22. The opening rate of the water collection flower wall 261 is 30%, and the hole diameter is 115*53 mm. A stainless steel mesh 263 is arranged between the water collection flower wall 261 and the water outlet area 22. The water outlet pipe 262 is arranged in the water collection channel 26. The water outlet pipe 262 is connected to the water collection channel 26. The water outlet pipe 262 is an adjustable water outlet pipe 262, which is used to adjust the water level in the A-O improved wetland 2. A submersible pump 264 is arranged between the anaerobic subsurface flow wetland 2 and the oxygen-enriched submerged plant surface flow wetland 3. The effluent from the oxygen-enriched submerged plant surface flow wetland treatment area is used for backwashing the anaerobic subsurface flow wetland treatment area.

[0077] The water inlet pipe 311 and the riprap 312 are arranged at the water inlet end of the oxygen-enriched submerged plant surface flow wetland treatment area 3. The canna indica 321 is planted on the upper part of the water inlet end. The planting soil layer 331 is arranged at the bottom. The bottom end of the planting soil layer 331 is provided with a 0.5 mm thick HDPE geomembrane 332. The bottom of the HDPE geomembrane 332 is provided with plain soil 333. The thickness of the planting soil layer 331 is 500 mm. The needle rush 322 and the hygroryza ovals 323 are planted on the planting soil layer 331 in sequence. The compaction degree of the plain soil is greater than 0.93. The drop wall 313 is arranged at the water outlet end of the oxygen-enriched submerged plant surface flow wetland treatment area 3.

[0078] The upper end of the water inlet area 21, the purification area 27 and the water outlet area 22 is provided with a planting soil layer 28 for planting plants, the thickness of the planting soil layer 28 is 200-300 mm, the bottom of the planting soil layer 28 is provided with a geotextile 291 with a density of 200 g / m2, the lower end of the purification area is paved with an HDPE geomembrane 292, the lower end of the HDPE geomembrane 292 is filled with a plain soil 293, the compaction degree of the plain soil 293 is greater than 0.93, the particle size of the modified zeolite filler is 4-8 mm, the thickness of the modified zeolite filler is 1200 mm, and the thickness of the HDPE geomembrane 292 is 0.5 mm.

[0079] As shown in Figure 6 The ecological conservation wetland 4 in the fourth step is formed by terrain and is in the form of deep pool and shallow beach, natural habitat is created, multiple types of plants are planted, aquatic animals are raised, and biological diversity is enriched.

[0080] The terrain forming process includes multiple grooves, modified zeolite 411 is paved in the groove near the water inlet end of the ecological conservation wetland 4, modified zeolite 441 is paved in the groove near the water outlet end of the ecological conservation wetland 4, denitrification type biological filter material 412 is paved on both sides of the secondary groove near the water inlet end and the water outlet end, composite biological filler 413 is paved on one side of the central groove of the ecological conservation wetland, and stone cage fish nest 414 is paved at the bottom of the other side; purple yam 421, water chestnut 422, Chinese senna or canna 423, purple yam 426, elodea 427, mulberry 424, vetiver 425 and needle kandelia 428 are planted in the ecological conservation wetland 4 from the water inlet end to the central groove.

[0081] The multi-stage A-O type oxidation pond in the fifth step includes floating leaf plant pond 5 and emergent plant pond 6, the floating leaf plant pond 5 and the emergent plant pond 6 are connected in series and communicated through waterfalls, and multiple stages are arranged; the water inlet end of the first-stage floating leaf plant pond 5 of the multi-stage A-O type oxidation pond is connected with the water outlet end of the ecological conservation wetland 4, and the water outlet end of the last-stage emergent plant pond 6 of the multi-stage A-O type oxidation pond is connected with the ecological river and lake self-purification area 7.

[0082] As shown in Figure 7As shown, the water inlet end of the floating leaf plant pond 5 is provided with a water inlet pipe 511 which is communicated with the water outlet pipe of the ecological conservation wetland 4, and the bottom of the water inlet end is provided with riprap 512, and the water outlet end is provided with a waterfall wall 513; the bottom of the floating leaf plant pond is provided with a planting soil layer 533, the bottom end of the planting soil layer 533 is provided with a 0.5mm HDPE geomembrane 532, the bottom of the HDPE geomembrane 532 is provided with plain soil 531, the thickness of the planting soil layer 533 is 500mm, and the compaction degree of the plain soil 531 is greater than 0.93; evergreen iris 521 and arrowhead 522 are planted on the upper part of the water inlet end of the floating leaf plant pond, and the upper end of the planting soil layer in the floating leaf plant pond is planted with lemnus 524 and nymphaea 523.

[0083] As shown in the figure, Figure 8 As shown, the water inlet end of the floating leaf plant pond 5 is provided with a water inlet pipe 511 which is communicated with the water outlet pipe of the ecological conservation wetland 4, and the bottom of the water inlet end is provided with riprap 512, and the water outlet end is provided with a waterfall wall 513; the bottom of the floating leaf plant pond is provided with a planting soil layer 533, the bottom end of the planting soil layer 533 is provided with a 0.5mm HDPE geomembrane 532, the bottom of the HDPE geomembrane 532 is provided with plain soil 531, the thickness of the planting soil layer 533 is 500mm, and the compaction degree of the plain soil 531 is greater than 0.93; evergreen iris 521 and arrowhead 522 are planted on the upper part of the water inlet end of the floating leaf plant pond, and the upper end of the planting soil layer in the floating leaf plant pond is planted with lemnus 524 and nymphaea 523.

[0084] As shown in the figure, Figure 9 As shown in the figure,

[0085] The above-mentioned purified water is recycled, which specifically includes greening irrigation water, road washing water, and surrounding landscape water supplement source.

[0086] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by the equivalent ones without departing from the spirit of the technical solutions of the present application, and all of them should be covered in the technical solution range claimed by the present application.

Claims

1. A method for constructing a low-carbon landscape-type ecological system for reducing nitrogen and phosphorus in surface river and lake water bodies, characterized in that, The method specifically comprises the following steps: Firstly, according to the target discharge of the water body to be treated, the water supplement calculated based on the water balance in the site, and a suitable adjustment coefficient, the total treatment scale of the ecological system is determined; The water quality of the water body to be treated is determined; The water quality target of the treated water is determined; Secondly, the water body to be treated is introduced into a multifunctional diversion and sedimentation channel to perform sedimentation treatment on the silt and suspended matter in the water body; The multifunctional diversion and sedimentation channel in the second step is in a long strip shape, the main structure is built by rubble retaining wall, the bottom is paved with 500mm planting soil after anti-seepage treatment, the bottom is sloped at 4‰ from the water inlet end to the water outlet end, and the egg stones, planting chrysanthemum and goldfish algae, and volcanic rock cage filter tank are scattered and paved in sequence to realize the sedimentation treatment on the silt and suspended matter in the surface river and lake water body, and reduce the silt and suspended matter content in the water inlet of the rear end A-O improved wetland; Thirdly, the water body treated by the multifunctional diversion and sedimentation channel is introduced into the A-O improved wetland to perform nitrogen reduction and phosphorus removal purification treatment on the water body by the A-O improved wetland; The A-O improved wetland in the third step comprises an anaerobic subsurface wetland treatment area and an oxygen-rich submerged plant surface flow wetland treatment area; the anaerobic subsurface wetland adopts horizontal flow form, and the sewage is purified by the physical, chemical and biological effects of the filler bed, plants and microorganisms in the wetland; Fourthly, the water body purified by the A-O improved wetland is introduced into the ecological conservation wetland to remove the nitrogen and phosphorus nutrients in the water body by the water purification filter material paved in the ecological conservation wetland, and a plurality of terrains are created in the ecological conservation wetland to create a natural habitat; The ecological conservation wetland in the fourth step is set in the form of deep pool and shallow beach by terrain creation to create a natural habitat, and a plurality of types of plants are planted and aquatic animals are raised; A plurality of grooves are arranged in the terrain creation, modified zeolite is paved in the grooves near the water inlet end and the water outlet end of the ecological conservation wetland, denitrification type biological filter material is paved on both sides of the second grooves near the water inlet end and the water outlet end, composite biological filler material is paved on one side of the central groove of the ecological conservation wetland, and stone cage fish nest is paved on the bottom of the other side; Fifthly, the water body purified by the ecological conservation wetland is introduced into the multi-stage A-O type oxidation pond to further perform nitrogen reduction and phosphorus removal purification treatment on the water body; Sixthly, the water body treated by the multi-stage A-O type oxidation pond is introduced into the ecological river and lake self-purification area, a stable aquatic plant purification system and an aquatic animal control system are constructed in the ecological river and lake self-purification area to realize in-situ purification of the incoming water, the water in the ecological river and lake self-purification area is purified for reuse to complete the nitrogen reduction and phosphorus removal purification target of the surface river and lake water body and the water recycling; The multi-stage A-O type oxidation pond in the fifth step comprises a floating leaf plant pond and an emergent plant pond, the floating leaf plant pond and the emergent plant pond are connected in series through drop water form and are provided with multiple stages; the water inlet end of the first-stage floating leaf plant pond of the multi-stage A-O type oxidation pond is connected with the water outlet end of the ecological conservation wetland through a connecting pipe, and the water outlet end of the last-stage emergent plant pond of the multi-stage A-O type oxidation pond is connected with the ecological river and lake self-purification area.

2. The method according to claim 1, wherein the method is characterized in that, Total processing scale of the ecosystem W in the first step z Target discharge water volume Q of the water body to be treated p The sum of the calculated water supplement W based on the water balance in the site, multiplied by an appropriate adjustment coefficient k, that is, W z =k*(Q p +W); the adjustment coefficient is comprehensively valued according to the site comprehensive land index and local rainfall, and is 1.1-1.3; the specific calculation formula of the water supplement is: , wherein W is the water supplement; is the landscape greening irrigation volume; is the lake bottom leakage volume of the water purification unit; is the evaporation water volume; is the water surface precipitation volume; is the surface runoff volume; the landscape greening irrigation volume includes the greening and road sprinkling volume.

3. The method according to claim 2, wherein the method is characterized in that, The specific calculation formula of the water purification unit lake bottom leakage amount is: Wherein m is the permeation amount 3 ; K is the permeation coefficient, m / s; J is the hydraulic slope, and the value of J is 1; s m is the effective permeation area 2 ; T s is the permeation time, s.

4. The method according to claim 1, wherein, The water source access total water inlet pipe is arranged on the retaining wall structure of one side of the multifunctional shunt sedimentation channel, the total water inlet pipe is arranged according to the total treatment scale of the ecological system and the shunt arrangement of the shunt sedimentation channel, so that the water flow velocity in the channel is 0.15-0.30 m / s, and the residence time is 45-60 s; pebbles are laid at the bottom of the water inlet end of the multifunctional shunt sedimentation channel, and the water inlet of the multifunctional shunt sedimentation channel is buffered; The water outlet pipe is arranged at the water outlet end of the multifunctional shunt sedimentation channel and is connected with the A-O improved wetland water inlet channel.

5. The method according to claim 1, wherein the method is characterized in that, The water body in the anaerobic subsurface wetland flows at the bottom of the soil and is prone to be anoxic, so the submerged plant surface flow wetland treatment area is arranged at the rear end of the anaerobic subsurface wetland; Vallisneria spinulosa and Hydrilla verticillata are planted in the submerged plant surface flow wetland treatment area, the roots of Vallisneria spinulosa and Hydrilla verticillata are embedded in the mud, the whole plant is submerged under the water surface, the root system and the whole leaf surface of the submerged plant directly absorb the nutrients in the water body and silt, the required carbon source is directly absorbed from the water body, and O2 generated by photosynthesis is directly dissolved in the water, so that the water body oxygen enrichment target is achieved.

6. The method according to claim 5, wherein the method is characterized in that, The anaerobic subsurface wetland treatment area and the oxygen-enriched submerged plant surface flow wetland treatment area are sloped according to the water flow direction, and the longitudinal slope i is 1‰-5‰; the anaerobic subsurface wetland treatment area comprises a water distribution channel, a water inlet area, a purification area, a water outlet area and a water collection channel; the water inlet area and the water outlet area are respectively arranged at the two sides of the purification area, the water inlet area is communicated with the water distribution channel, the water distribution channel is connected with the multifunctional shunt sedimentation channel through a water distribution pipe, and a valve well is arranged on the water distribution pipe; a stop valve and a check valve are arranged in the valve well; the water outlet area is connected with the water collection channel, the water collection channel is provided with a water outlet pipe and a submersible pump, and the water outlet pipe and the submersible pump are communicated with the oxygen-enriched submerged plant surface flow wetland treatment area.

7. The method according to claim 6, wherein the method is characterized in that, One end of the water distribution channel is connected with the water distribution pipe, the other end of the water distribution channel is connected with the water inlet area, a 1500mm-thick paddle stone retaining wall is arranged at the one end of the water distribution channel connected with the water distribution pipe, a water distribution flower wall is arranged at the one end of the water distribution channel connected with the water inlet area, the thickness of the water distribution flower wall is 1200mm, the opening rate of the water distribution flower wall is 30%, the hole diameter of the water distribution flower wall is 115*53mm, and a stainless steel mesh is arranged on the water distribution flower wall close to the water inlet area; the water body in the multifunctional shunt sedimentation channel enters the water distribution channel through the water distribution pipe and then enters the water inlet area through the water distribution flower wall; a cover plate is arranged at the upper end of the water distribution channel, and the cover plate is made of 150mm-thick reinforced concrete.

8. The method according to claim 7, wherein the method is characterized in that, The two sides of the multifunctional shunt sedimentation channel are rough stone retaining wall structures, the slope ratio of the retaining wall structure is 10:1, and waterproof mortar is arranged on the inner side of the retaining wall structure; HDPE geomembrane is laid at the bottom of the multifunctional shunt sedimentation channel for anti-seepage treatment, a fine sand leveling layer is arranged at the bottom of the HDPE geomembrane, the bottom of the fine sand leveling layer is rammed with plain soil, a fine sand leveling layer is arranged at the upper part of the HDPE geomembrane, and a planting soil layer is arranged on the upper part of the fine sand leveling layer; a concrete coping is arranged at the upper end of the retaining wall structure, a concrete foundation is arranged at the bottom end of the retaining wall structure, and a plain concrete cushion layer is arranged at the lower end of the concrete foundation.

9. The method according to claim 8, wherein the method is characterized in that, The thickness of the HDPE geomembrane laid at the bottom of the multifunctional diversion sedimentation channel is 0.5 mm, the thickness of the fine sand leveling layer is 100 mm, the thickness of the planting soil layer is 500 mm, and the compaction degrees of the planting soil layer and the plain soil are both greater than 0.93; the thickness of the waterproof mortar is 30 mm, the thickness of the concrete pressure top is 100 mm, the thickness of the concrete foundation is 200 mm, and the thickness of the plain concrete cushion layer is 100 mm.

10. The method according to claim 9, wherein the method is characterized in that, The water inlet area is filled with gravel and volcanic rock mixed fillers, the width of the mixed fillers is 1 m, the particle size of the gravel is 15-25 mm, the particle size of the volcanic rock is 10-80 mm, and the void ratio of the mixed fillers is 40%-50%.

11. The method according to claim 9, wherein the method is characterized in that, The water outlet area is filled with gravel and volcanic rock mixed fillers, the width of the gravel and volcanic rock mixed fillers is 0.8 m, the particle size of the gravel is 10-15 mm, the particle size of the volcanic rock is 10-80 mm, the void ratio of the mixed fillers is 30%-35%, one side of the water outlet area is connected with the water collecting channel, the water collecting channel comprises a water collecting flower wall and a water outlet pipe, the water collecting flower wall is connected with the water outlet area, the opening rate of the water collecting flower wall is 30%, the hole diameter of the water collecting flower wall is 115*53 mm, and a stainless steel mesh is arranged between the water collecting flower wall and the water outlet area; a water outlet pipe is further arranged in the water collecting channel, the water outlet pipe is connected with the water collecting channel, the water outlet pipe is an adjustable water outlet pipe, and the water outlet pipe is used for adjusting the water level in the A-O improved wetland; a submerged pump is arranged between the anaerobic subsurface flow wetland and the oxygen-rich submerged plant surface flow wetland, and the effluent of the oxygen-rich submerged plant surface flow wetland treatment area is used for backwashing the anaerobic subsurface flow wetland treatment area.

12. The method according to claim 1, wherein the method is characterized in that, The water inlet area is filled with gravel and volcanic rock mixed fillers, the width of the mixed fillers is 1 m, the particle size of the gravel is 15-25 mm, the particle size of the volcanic rock is 10-80 mm, and the void ratio of the mixed fillers is 40%-50%.

13. The method according to claim 9, wherein the method is characterized in that, The water inlet area, the purification area and the water outlet area are provided with a planting soil layer at the upper end, the planting soil layer is used for planting plants, the thickness of the planting soil layer is 200-300 mm, geotextile is arranged at the bottom of the planting soil layer, the density of the geotextile is 200 g / m2, the purification area is filled with modified zeolite fillers, a fine sand leveling layer is laid at the lower end of the modified zeolite fillers, the lower end of the water inlet area and the lower end of the water outlet area, an HDPE geomembrane is laid at the lower end of the fine sand leveling layer, a fine sand leveling layer is laid at the lower end of the HDPE geomembrane, plain soil is arranged at the lower end of the fine sand leveling layer, the compaction degree of the plain soil is greater than 0.93, the particle size of the modified zeolite fillers is 4-8 mm, the thickness of the modified zeolite fillers is 1200 mm, the thickness of the HDPE geomembrane is 0.5 mm, and the thickness of the fine sand leveling layer is 100 mm.

14. The method according to claim 1, wherein the method is characterized in that, The ecological conservation wetland is planted with purple canna, cattail, Chinese milkvetch, or canna, cattail, common club-rush, mulberry, vetiver, and spiked sedge from the water inlet end to the middle groove.

15. The method according to claim 1, wherein the method is characterized in that, The single pond length-width ratio of the floating leaf plant pond and the emergent plant pond is 4:1; the effective water depth of the floating leaf plant pond is 1200-1500 mm, the silt layer is 200 mm, and the super height is 300-500 mm; the effective water depth of the emergent plant pond is 300-500 mm, the silt layer is 100 mm, and the super height is 300 mm; the hydraulic retention time of the floating leaf plant pond is 15 days, and the hydraulic retention time of the emergent plant pond is 10 days.

16. A method for creating a low-carbon landscape ecosystem for nitrogen and phosphorus removal in surface rivers and lakes according to claim 15, characterized in that, The water inlet end of the floating leaf plant pond is provided with a water inlet pipe, which is communicated with the water outlet pipe of the ecological conservation wetland, and the bottom of the water inlet end is provided with riprap, and the water outlet end is provided with a drop wall; the bottom of the floating leaf plant pond is provided with a planting soil layer, the bottom end of the planting soil layer is provided with a 0.5 mm HDPE geomembrane, the bottom of the HDPE geomembrane is provided with plain soil, the thickness of the planting soil layer is 500 mm, and the compaction degree of the plain soil is greater than 0.93; evergreen iris and arrowhead are planted on the upper part of the water inlet end of the floating leaf plant pond, and the upper end of the planting soil layer in the floating leaf plant pond is planted with duckweed and water lily.

17. A method for creating a low-carbon landscape ecosystem for nitrogen and phosphorus removal in surface rivers and lakes according to claim 15, characterized in that, The water inlet end of the emergent plant pond is provided with a drop wall, and the water outlet end is provided with a water outlet pipe and riprap; the bottom of the emergent plant pond is provided with a planting soil layer, the bottom end of the planting soil layer is provided with a 0.5 mm HDPE geomembrane, the bottom of the HDPE geomembrane is provided with plain soil, the thickness of the planting soil layer is 500 mm, and the compaction degree of the plain soil is greater than 0.93; the water inlet end of the emergent plant pond is planted with umbrella grass, and the water outlet end is planted with alisma orientale.

18. The method according to claim 1, wherein the method is characterized in that, The bottom of the ecological river and lake self-purification area is provided with a planting soil layer, the thickness of the planting soil layer is 500 mm, the upper end of the planting soil layer is a constant water level area, the center water depth is 1500-3000 mm, and the bottom end of the planting soil layer is provided with anti-seepage treatment measures; the middle part of the ecological river and lake self-purification area is selectively planted with a community of spiked sedge, small nuphar, large nuphar, common club-rush, and hygroryza ovals; the shore zone around the ecological river and lake self-purification area is sequentially planted with a community of sphaerocarpus, iris, spikerush, and dwarf cold-tolerant sedge; the water inlet end of the ecological river and lake self-purification area is provided with a water inlet pipe and riprap; aquatic animals including fish, snails, shrimps, shellfish, and plankton are put into the ecological river and lake self-purification area.

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