A horizontal flow artificial wetland and construction method thereof

Abstract

The present application relates to a horizontal flow artificial wetland and a construction method thereof, and to the technical field of artificial wetlands. The horizontal flow artificial wetland comprises a unit pool and an anti-seepage structure laid on the bottom of the unit pool. The unit pool is surrounded by side walls, and an inlet area and an outlet area are respectively arranged on the anti-seepage structure on the inner sides of the two side walls. A water distribution pipe is arranged in the inlet area, a water collection pipe is arranged in the outlet area, and a biological purification area is arranged between the inlet area and the outlet area. The biological purification area comprises a coarse volcanic rock layer, a biological ceramsite layer and a coarse gravel layer arranged in sequence from the inlet area to the outlet area. The present application has the effect of reducing the blockage phenomenon of the artificial wetland.

Description

Technical Field

[0001] The present application relates to the field of artificial wetlands, and in particular to a horizontal flow artificial wetland and a construction method thereof. Background Art

[0002] Wetlands are transitional zones between terrestrial and aquatic ecosystems and are ecosystems with the highest primary productivity. Artificial wetlands are essentially a comprehensive ecosystem that is derived from the simulation of natural wetlands. They mainly utilize the regeneration of energy and material cycles of various symbiotic species in the ecosystem. On the premise of promoting the benign cycle of pollutants in wastewater, they give full play to the resource production potential, obtain the best benefits of sewage treatment and resource utilization, and prevent sewage from causing secondary pollution to the environment.

[0003] Wetland sewage treatment system is a better way to treat wastewater, especially it gives full play to the production potential of resources, prevents environmental re-pollution, and obtains the best benefits of sewage treatment and resource utilization, so it has high environmental benefits, economic benefits and social benefits. With the continuous research on wetland sewage treatment system, the unique and complex purification mechanism of wetlands enables it to play a good role in the treatment of heavy metal industrial wastewater and non-degradable organic wastewater. Therefore, the application of artificial wetland sewage treatment system has gradually shifted from domestic sewage, industrial wastewater and agricultural sewage treatment. It can be said that wetland sewage treatment technology will be more and more valued by people and will be increasingly widely used.

[0004] After a period of operation, the matrix of an artificial wetland is prone to clogging, which will cause a sharp drop in the permeability coefficient of the wetland matrix, reduce the water flow capacity, cause odor, breed mosquitoes and flies, deteriorate the operating environment, and reduce the removal effect of pollutants. Summary of the invention

[0005] In order to alleviate the clogging phenomenon of artificial wetlands, the present application provides a horizontal flow artificial wetland and a construction method thereof.

[0006] In a first aspect, the present application provides a horizontal flow artificial wetland, which adopts the following technical solution:

[0007] A horizontal flow artificial wetland comprises a unit pool and an anti-seepage structure laid on the bottom layer of the unit pool, wherein the unit pool is surrounded by side walls, and an inlet area and an outlet area are respectively arranged on the anti-seepage structure on the inner sides of the two side walls, wherein a water distribution pipe is arranged in the water inlet area, a water collecting pipe is arranged in the water outlet area, and a biological purification area is arranged between the water inlet area and the water outlet area, wherein the biological purification area comprises a coarse volcanic rock layer, a biological ceramsite layer and a coarse crushed stone layer which are arranged in sequence from the water inlet area to the water outlet area.

[0008] By adopting the above technical scheme, the anti-seepage structure can prevent water seepage from the bottom of the unit pool. The biological purification area is used to purify the water quality. The water inlet area, biological purification area and water outlet area are arranged horizontally, and the lower pressure is small, which is conducive to the flow of water. The coarse volcanic rock layer, biological ceramsite and coarse crushed stone layer used in the biological purification area are all fillers with larger particle size, larger gaps, strong adhesion ability, not easy to be blocked, and long service life. In addition, the horizontal arrangement of the layer structure can facilitate the replacement of fillers in any area and facilitate later maintenance.

[0009] Optionally, the anti-seepage structure includes a lower protective fine-grained soil layer, an anti-seepage membrane and an upper protective fine-grained soil layer arranged in sequence from bottom to top.

[0010] By adopting the above technical solution, the upper protective fine-grained soil layer and the lower protective fine-grained soil layer can protect the anti-seepage membrane.

[0011] Optionally, non-woven fabric is arranged between the anti-seepage structure and the water inlet area, biological purification area and water outlet area above the anti-seepage structure.

[0012] By adopting the above technical solution, the non-woven fabric can play an isolating role and prevent material mixing.

[0013] Optionally, the bottom of the unit pool is inclined, and the water inlet area is higher than the water outlet area.

[0014] The adoption of the above technical solution is conducive to the flow of water from the water inlet area to the water outlet area.

[0015] Optionally, the water inlet area and the water outlet area are both paved with fine crushed stones.

[0016] By adopting the above technical solution, the fine crushed stone is conducive to water infiltration and can perform preliminary and final filtering functions.

[0017] Optionally, partitions are provided between any two adjacent areas of the water inlet area, the coarse volcanic rock layer, the biological ceramsite layer, the coarse gravel layer and the water outlet area.

[0018] By adopting the above technical solution, the partition plays a supporting and isolating role, and when filling the base material of the layer structure on both sides of the partition, mixing of materials can be prevented to avoid affecting the water purification effect.

[0019] Optionally, the partition includes two layers of isolation nets and a partition plate clamped between the two layers of isolation nets, and the partition plate can be pulled out from above.

[0020] By adopting the above technical solution, after the layer structures on both sides of the partition are filled, the partition is pulled out from the top, and the two layers of isolation nets are closed together under the pressure of the base material, which can penetrate water and play an isolation role to prevent mixing during later use.

[0021] Optionally, the bottoms of the two layers of isolation nets extend in opposite directions respectively.

[0022] By adopting the above technical solution, the bottom of the isolation net is pressed by the base material, which can prevent the isolation net from being taken out when the partition is pulled out.

[0023] In a second aspect, the present application provides a construction method for a horizontal flow artificial wetland, which adopts the following technical solution:

[0024] A construction method for a horizontal flow artificial wetland comprises the following construction steps:

[0025] S1. Fill the unit pool with anti-seepage structure according to the water inlet direction, and install the water distribution pipe when laying the water inlet area;

[0026] S2. A cross-wall road is laid on the top of the unit pool to facilitate the use of loaders, excavators and other machinery to fill the biological purification area and the water outlet area in the deep of the unit pool. The cross-wall road and the upper layer of the paved filler in the unit pool are protected and separated by non-woven fabrics and protective plates;

[0027] S3. During the paving process, partitions are set at the boundaries of the water inlet area, coarse volcanic rock layer, biological ceramsite layer, coarse crushed stone layer and each layer of structural filler in the water outlet area. The fillers on both sides of the partition rise evenly, and the partition plates of the partition are slowly lifted as the fillers rise;

[0028] S4. When laying the outlet area, it is divided into two layers, the upper and lower layers are filled to the height of the first layer, the pipe trench is dug manually, the water collecting pipe is installed, and the pipe trench is backfilled manually. After the pipe trench is backfilled, the second layer of filling is carried out to the designed elevation;

[0029] S5. Push small loaders, small single-bucket excavators and other machinery out of the unit pool along the cross-wall road, and then clear the cross-wall road.

[0030] By adopting the above technical solution, the paving of the cross-wall road can provide machinery for walking and realize mechanized filling, thereby improving construction efficiency. The partition is set between adjacent layer structures to prevent mixing of materials. The fillings on both sides of the partition rise evenly, so that the partition is evenly stressed to avoid tipping over. The partition is slowly lifted as the filling rises to avoid difficulty in lifting due to excessive friction.

[0031] Optionally, in step S2, non-woven fabric and protective panels are used to separate the cross-wall road and the paved unit pool filler.

[0032] By adopting the above technical solution, the cross-wall road is prevented from mixing with the fillers of the unit pool, and it is convenient to clear the cross-wall road.

[0033] In summary, the present application includes at least one of the following beneficial technical effects:

[0034] 1. The coarse volcanic rock layer, biological ceramsite and coarse crushed stone layer used in the biological purification area are all fillers with larger particle size, larger gaps, strong adhesion ability, not easy to be blocked, and long service life;

[0035] 2. After the layer structures on both sides of the partition are filled, the partition is pulled out from the top. The two layers of isolation nets are close together under the pressure of the base material, which can penetrate water and play an isolation role to prevent mixing during later use;

[0036] 3. During the filling construction, laying a cross-wall road can provide space for machinery to travel, thus realizing mechanized filling and improving construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the overall structure of a horizontal flow artificial wetland;

[0038] Figure 2 It is a schematic diagram of the anti-seepage structure and partition of the horizontal flow artificial wetland;

[0039] Figure 3 An overhead view of the paved cross-wall road in the horizontal flow constructed wetland.

[0040] Explanation of the reference numerals in the accompanying drawings: 1. Side wall; 2. Anti-seepage structure; 21. Lower protective fine-grained soil layer; 22. Anti-seepage membrane; 23. Upper protective fine-grained soil layer; 3. Water inlet area; 31. Water distribution pipe; 4. Biological purification area; 41. Coarse volcanic rock layer; 42. Biological ceramsite layer; 43. Coarse gravel layer; 5. Water outlet area; 51. Water collecting pipe; 6. Non-woven fabric; 7. Partition; 71. Partition board; 72. Isolation net; 8. Cross-wall road. DETAILED DESCRIPTION

[0041] The present application is further described in detail below in conjunction with the accompanying drawings.

[0042] The present application embodiment discloses a horizontal flow artificial wetland. Figure 1 The horizontal flow artificial wetland includes a plurality of unit pools with the same structure and arranged in parallel. Each unit pool includes a concrete side wall 1 and an impermeable structure 2 laid on the bottom of the unit pool. The filler laid above the impermeable structure 2 is divided into an inlet area 3, a biological purification area 4 and an outlet area 5. The inlet area 3 and the outlet area 5 are respectively arranged on the inner sides of the two opposite side walls 1, and the biological purification area 4 is arranged between the inlet area 3 and the outlet area 5. Water flows from the inlet area 3 through filtration in the biological purification area 4 to the outlet area 5.

[0043] Reference Figure 1 and Figure 2The bottom of the unit pool is tilted at a certain angle so that the side of the water inlet area 3 is higher than the side of the water outlet area 5. The anti-seepage structure 2 includes a lower protective fine-grained soil layer 21, an anti-seepage membrane 22, and an upper protective fine-grained soil layer 23 arranged from bottom to top. The lower protective fine-grained soil layer 21 also serves as a leveling layer, and the thickness can be set to 100mm, the thickness of the anti-seepage membrane 22 can be set to 1mm, and the thickness of the upper protective fine-grained soil layer can be set to 300mm-400mm. Non-woven fabric 6 can be laid above the upper protective fine-grained soil layer to separate it from the upper water inlet area 3, biological purification area 4 and water outlet area 5 to prevent mixing.

[0044] Reference Figure 1 The water inlet area 3 and the water outlet area 5 are both paved with fine crushed stones, and the particle size of the fine crushed stones can be selected to be 16-32 mm. The water inlet area 3 is provided with a water distribution pipe 31, one end of which is located in the water inlet area 3 and is set as a porous structure, and the other end passes through the side wall 1 on one side of the water inlet area 3. The water outlet area 5 is provided with a water collecting pipe 51, one end of which is located in the water outlet area 5 and is set as a porous structure, and the other end passes through the side wall 1 on one side of the water outlet area 5. The position of the water distribution pipe 31 is higher than the water collecting pipe 51, and both the water distribution pipe 31 and the water collecting pipe 51 can adopt dn200PVC~U pressure pipes.

[0045] The biological purification area 4 includes a coarse volcanic rock layer 41, a biological ceramsite layer 42 and a coarse crushed stone layer 43 which are arranged transversely in sequence from the water inlet area 3 to the water outlet area 5, and the particle size of each of them can be selected to be 8-16 mm.

[0046] Fine crushed stone and coarse crushed stone are natural or artificial crushed granular materials with a certain grade, such as limestone crushed stone, which are formed by natural granular ore or artificial crushing. Main technical requirements:

[0047] (1) Main components: natural ore components containing calcium (calculated as CaCO3) by mass ratio ≥ 60%; crushed stone density: > 2.5t / m3, without visible soil, powder, or organic impurities;

[0048] (2) Chemical properties: It has strong stability, does not dissolve in water, and does not contain toxic substances;

[0049] (3) Particle size range: In a crushed stone particle size range as required by the construction drawings, the amount of particles larger than the maximum particle size is less than 5%, and the amount of particles smaller than the minimum particle size is less than 5%;

[0050] (4) Non-uniformity coefficient: The non-uniformity coefficient refers to the ratio of the sieve holes through which 80% of the mass of the crushed stone filter material passes to the sieve holes through which 10% of the mass passes. The non-uniformity coefficient is ≤1.6.

[0051] The coarse volcanic rock layer 41 utilizes its porous, loose, and rough natural properties to increase the biofilm-forming capacity of microorganisms, increase the number of microorganisms, and improve the wetland purification efficiency. The technical requirements are as follows:

[0052] (1) Bulk density: 0.7-0.9 g / cm3, inspect and constrain the material: because there is a difference between the apparent density and the bulk density, the void ratio can generally reach more than 50%, that is, the apparent density is about twice the bulk density;

[0053] (2) The void ratio is ≥50%, which limits the looseness of the filler and ensures the residence time of wetland water;

[0054] (3) Mud content ≤ 1%, limiting the purity and voids of the filler to ensure the residence time of wetland water;

[0055] (4) The compressive strength or cylinder pressure strength is ≥5.0MPa, which can restrict the quality of the packing and ensure the service life of the packing;

[0056] (5) Specific surface area>5m2 / g, restricting the roughness of the filler to ensure the wetland water purification effect;

[0057] (6) Particle size range: The amount of particles with a size larger than the maximum particle size is less than 5%, and the amount of particles with a size smaller than the minimum particle size is less than 5%.

[0058] The main function of the biological ceramsite layer 42 is to introduce initial microorganisms, domesticate and guide the wetland microbial ecology, increase the number of initial filler microorganisms, improve the wetland purification efficiency, shorten the wetland maturity time, and maximize the wetland water purification capacity as soon as possible. Biological ceramsite is a composite filler formed by a layer of microbial film wrapped around aggregate with a rough surface. It is a semi-stable process product with no fixed standards and specifications. It is mainly controlled by experience. The effective microbial flora of the proposed film-coated microbial raw material and the film thickness are used as the main control indicators. Its technical requirements are as follows:

[0059] (1) The total number of viable bacteria is ≥ 2 billion CFU / g. To ensure that the colonies are effective bacteria, they can be enumerated as appropriate, that is, the number of specific effective bacteria, such as lactic acid bacteria, yeast, etc., can be tested;

[0060] (2) Aggregate particle coating thickness ≥ 0.5 mm;

[0061] (3) The carrier structure is selected from one or more of crushed stone, regenerated stone, and limestone, and the applicable particle size is 8 to 16 mm;

[0062] (4) The content of particles that do not meet the requirements of particle grading is ≤5%, the mud content (by mass) is ≤1.0%, and there should be no debris such as grass roots, leaves, branches, plastics, coal blocks and slag;

[0063] (5) It has strong stability, does not dissolve in water, does not contain toxic substances, does not dissolve harmful substances, and does not cause secondary pollution.

[0064] Reference Figure 2 A vertical partition 7 is provided between any two adjacent areas of the water inlet area 3, the coarse volcanic rock layer 41, the biological ceramsite layer 42, the coarse gravel layer 43 and the water outlet area 5 to prevent mixing of adjacent areas. The partition 7 includes a partition 71 and two layers of isolation nets 72. The partition 71 can be a hard plywood, and the two layers of isolation nets 72 are respectively attached to both sides of the partition 71. The partition 71 plays a supporting role during the filling construction process. After the filling construction is completed, the partition 71 is pulled out from the top. The two layers of isolation nets 72 are closed under the pressure of the layer structures on both sides, which can seep water and continue to prevent mixing of the two sides. The bottoms of the two layers of isolation nets 72 can extend to the opposite sides respectively, pressed between the non-woven fabric 6 and the layer structure above, to prevent the isolation nets 72 from being taken out when the partition 71 is pulled out.

[0065] The implementation principle of a horizontal flow artificial wetland in an embodiment of the present application is as follows: the water inlet area 3, the biological purification area 4 and the water outlet area 5 adopt a horizontal layer structure, and the lower pressure is relatively small, which is conducive to maintaining the gap between the base materials, thereby facilitating the flow of water. The coarse volcanic rock layer 41, biological ceramsite and coarse crushed stone layer 43 used in the biological purification area 4 are all fillers with larger particle sizes, larger gaps, strong adhesion ability, not easy to be blocked, and long service life. In addition, the horizontal arrangement of the layer structure can facilitate the replacement of fillers in any area, which is easy for later maintenance.

[0066] The present application also discloses a method for constructing a horizontal flow artificial wetland. The method for constructing a horizontal flow artificial wetland is used to lay the unit pool of the horizontal flow artificial wetland, and includes the following construction steps:

[0067] S1. Fill the unit pool with the anti-seepage structure 2 in the direction of water inflow. First, use an excavator to fill the unit pool directly from the top of the side wall 1 on one side of the water inlet area 3, and manually level the material. When laying the water inlet area 3, divide it into two layers, fill it to the height of the first layer, manually dig out the pipe trench, install the water distribution pipe 31, and manually backfill the pipe trench. After the backfilling of the pipe trench is completed, the second layer of filling is carried out to the designed elevation.

[0068] S2, reference Figure 3, pave the cross-wall road 8, so that the biological purification area 4 and the water outlet area 5 can be filled with loaders, excavators and other machinery in the deep of the unit pool. First, backfill the partition side wall 1 with a width of 4m and a height consistent with the top height of the side wall 1. Crushed stones are used to pave the cross-wall road 8 above the top of the side wall 1. The cross-wall road 8 is 4m wide. The cross-wall road 8 and the upper layer of the paved filler in the unit pool are protected and separated by non-woven fabrics 6 and protective plates to prevent the crushed stones of the cross-wall road 8 from mixing with the filler in the middle structure of the unit pool. The filler in the deep of the unit pool is carried out by a small loader, and a small single-bucket excavator is used to cooperate with manual leveling to fill the filler to the designed elevation at one time. The working surface and walking place of the small loader and small single-bucket excavator are planned in advance, and protective plates are added on both sides of the cross-wall road 8.

[0069] S3. During the paving process, partitions 7 are set at the boundaries of the structural fillers in the water inlet area 3, the coarse volcanic rock layer 41, the biological ceramsite layer 42, the coarse crushed stone layer 43 and the water outlet area 5. The fillers on both sides of the partition 7 rise evenly, and the partition 71 of the partition 7 is slowly lifted along with the rising speed of the fillers until the fillers reach the designed elevation.

[0070] S4, when laying the water outlet area 5, it is divided into upper and lower layers, filled to the height of the first layer, the pipe trench is dug manually, the water collecting pipe 51 is installed, the pipe trench is backfilled manually, and after the pipe trench is backfilled, the second layer of filling is carried out to the designed elevation.

[0071] S5, push small loaders, small single-bucket excavators and other machinery out of the unit pool along the cross-wall road 8, and then clear the cross-wall road 8.

[0072] In the above-mentioned horizontal flow artificial wetland construction method, the laying of cross-wall roads is adopted to realize mechanized construction deep in the unit pool, thereby ensuring construction efficiency.

[0073] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A construction method for a horizontal flow artificial wetland, characterized in that: The horizontal flow artificial wetland comprises a unit pool and an anti-seepage structure (2) laid on the bottom of the unit pool. The unit pool is surrounded by side walls (1). An inlet area (3) and an outlet area (5) are arranged on the anti-seepage structure (2) on the inner sides of the two side walls (1). The inlet area (3) and the outlet area (5) are both paved with fine crushed stones. A water distribution pipe (31) is arranged in the inlet area (3), and a water collection pipe (51) is arranged in the outlet area (5). A biological purification area (4) is arranged between the inlet area (3) and the outlet area (5). The biological purification area (4) comprises coarse fire slurry arranged in sequence from the inlet area (3) to the outlet area (5). A mountain rock layer (41), a biological ceramsite layer (42) and a coarse crushed stone layer (43); a partition (7) is arranged between any two adjacent areas of the water inlet area (3), the coarse volcanic rock layer (41), the biological ceramsite layer (42), the coarse crushed stone layer (43) and the water outlet area (5); the partition (7) comprises two layers of isolation nets (72) and a partition (71) clamped between the two layers of isolation nets (72), and the partition (71) can be pulled out from the top; a non-woven fabric (6) is arranged between the anti-seepage structure (2) and the water inlet area (3), the biological purification area (4) and the water outlet area (5) above it, and the bottoms of the two layers of the isolation nets (72) are oriented in opposite directions. The construction method comprises the following construction steps: S1, filling the unit pool with the anti-seepage structure (2) in the direction of water inlet, and installing the water distribution pipe (31) when laying the water inlet area (3); S2, laying a cross-wall road (8) on the top of the unit pool, so as to facilitate the use of loaders, excavators and other machinery to fill the biological purification area (4) and the water outlet area (5) in the deep of the unit pool, and the cross-wall road (8) and the upper layer of the filling material laid in the unit pool are protected and separated by non-woven fabric (6) and protective plates; S3, during the paving process, the water inlet area (3), partitions (7) are set at the boundaries of the coarse volcanic rock layer (41), the biological ceramsite layer (42), the coarse crushed stone layer (43) and the water outlet area (5), and the fillers on both sides of the partition (7) rise evenly, and the partition (71) of the partition (7) is slowly lifted along with the rising speed of the fillers; S4, when laying the water outlet area (5), it is divided into upper and lower layers, filled to the height of the first layer, manually digging a trench, installing a water collection pipe (51), and manually backfilling the trench. After the trench is backfilled, the second layer of filling is carried out to the designed elevation; S5, small loaders and small single-bucket excavators and other machinery are pushed out of the unit pool along the cross-wall road (8), and then the cross-wall road (8) is cleared away.

2. The construction method of horizontal flow artificial wetland according to claim 1, characterized in that: The anti-seepage structure (2) comprises a lower protective fine-grained soil layer (21), an anti-seepage membrane (22) and an upper protective fine-grained soil layer (23) which are arranged in sequence from bottom to top.

3. The construction method of horizontal flow artificial wetland according to claim 1, characterized in that: The bottom of the unit pool is arranged to be inclined, and the water inlet area (3) is higher than the water outlet area (5).

4. The construction method of a horizontal flow artificial wetland according to any one of claims 1 to 3, characterized in that: In step S2, the cross-wall road (8) and the paved unit pool filler are separated by non-woven fabric (6) and a protective plate.

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